Patent Publication Number: US-11377858-B2

Title: Flooring system provided with a connecting system and an associated connecting device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of Swedish Application No. 1950015-6, filed on Jan. 8, 2019. The entire contents of Swedish Application No. 1950015-6 are hereby incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The disclosure generally relates to a flooring system, such as a decking system, comprising floor elements and a connecting system for connecting the floor elements. More specifically, the flooring system comprises a connecting device for mechanical connection of the floor elements. The disclosure also relates to the connecting device itself. 
     BACKGROUND 
     Separate clips or rails for locking floor panels, such as decking panels, to a support structure, e.g. joists, are known. Typically, a situation arises in which an arbitrary floor panel in a set of installed floor panels needs to be removed, such as when the panel is damaged or when access to an area under the installed panels is desired. The known clips or rails, however, are configured such that it is cumbersome to remove an arbitrary floor panel in the set of installed floor panels. Moreover, it is typically equally cumbersome to reinstall the panel or install a new panel replacing the removed panel. 
     For instance, according to some solutions, such as that disclosed in EP 1 567 731 B1, a floor strip mounting component used for connecting floor boards needs to be irreparably broken in order to remove an installed floor board. 
     Furthermore, EP 3 112 551 A1 discloses a mounting part for fastening visible profiles in a terrace system. The mounting part comprises retaining bars that are configured to engage with a respective recess in a pair of adjacent visible profiles. A rigid structural section is formed on the mounting part for a fixed mounting of a first visible profile, and an elastic structural section is formed on the mounting part for a movable mounting of a second visible profile. However, the elastic structural section is elastic only to a small degree for admitting a pre-tensioning of a retaining bar of the mounting part. Thereby, an arbitrary visible profile in a set of fastened visible profiles cannot be removed without removing a sequence of visible profiles. 
     SUMMARY 
     It is therefore an object of at least exemplary embodiments of the present inventive concept to provide a flooring system, such as a decking system, comprising floor elements and a connecting system comprising a connecting device in which an arbitrary floor element may be removed, in particular without damaging any component of the flooring system, such as a floor element or the connecting device. 
     It is also an object of at least exemplary embodiments of the present inventive concept to provide such a flooring system while providing a reliable connecting strength between the floor elements. 
     Additionally, it is an object of at least exemplary embodiments of the present inventive concept to provide such a flooring system whereby a transverse distance between the floor elements may be controlled in an improved manner. 
     It is also an object of at least exemplary embodiments of the present inventive concept to provide a corresponding connecting device for a flooring system in accordance with any of the objects above. 
     At least some of these and other objects and advantages that will be apparent from the description have been achieved by the various aspects described below. 
     In accordance with a first exemplary aspect of the inventive concept, there is provided a flooring system, such as a decking system, comprising floor elements and a connecting system comprising a connecting device for connecting a first floor element and a second floor element. The connecting device comprises a first and a second connecting portion. An edge portion of the first and second floor elements comprises a first and a second engagement portion, respectively. The first and the second connecting portions are configured to cooperate—for example, engage—with the first and the second engagement portions, respectively, for vertically connecting the first and second floor elements. The connecting device further comprises a displaceable portion which is horizontally displaceable, preferably along a width direction of the connecting device. 
     Due to a reduced horizontal extension of the connecting device, the first and second floor elements may be at least partly, and for example completely, disconnected from each other when the displaceable portion is displaced. In particular, one or both of the first and second floor elements may be removed from the flooring system, such as by angling and/or a vertical displacement of the respective floor element. At least in some embodiments, the disconnection may be achieved without using any tools. 
     Each floor element may be a decking element, such as a decking panel. The floor element, such as the decking element, may comprise wood, such as softwood or hardwood, timber, lumber, treated lumber, pressure treated lumber, composite lumber, composite material, such as wood-plastic composite (WPC), or aluminium. Exemplary embodiments of the present disclosure can be particularly advantageous for, but not limited to, floor elements that are fairly dimensionally stable, e.g. under variations of an ambient temperature and/or humidity. 
     Each floor element may extend in a transverse direction and in a longitudinal direction, both being horizontal directions extending in a horizontal plane. The longitudinal extension preferably is larger than the transverse extension. The horizontal plane may extend in the transverse direction and in the longitudinal direction. The horizontal plane may be parallel with a top side and/or an underside of each floor element. The top side may be a visible side of the floor element. Each floor element may also extend in a vertical direction which is perpendicular to the horizontal plane. By upwards and downwards is meant a direction away from a top side of the floor element and away from an underside of the floor element, respectively. 
     Preferably, the floor elements are essentially identical. 
     The connecting device may have an extension in a width direction and in a depth direction. Moreover, the connecting device may extend in a vertical direction which is perpendicular to the width and depth directions. The depth direction and the width direction of the connecting device may be parallel with the longitudinal direction and the transverse direction of the first and second floor elements, respectively, when the first and second floor elements are connected. The vertical direction of the connecting device may be parallel to the vertical direction of the floor elements when the first and second floor elements are connected. 
     The first and second connecting portions may be disposed on the connecting device at different positions along its width direction, preferably at opposite sides of the connecting device. Each connecting portion may extend along the depth direction. 
     In the first horizontal state, the first connecting portion and/or the second connecting portion may extend essentially in parallel with a top side and/or an underside of the floor elements. Moreover, the first connecting portion and/or the second connecting portion may include a respective surface that is essentially parallel to the top side and/or the underside of the floor elements. The respective surface may be a first and a second bottom surface of a first and a second protrusion on which the first and second connecting portions may be provided. Alternatively, or additionally, the first engagement portion and/or the second engagement portion may extend essentially in parallel with the top side and/or the underside of the floor elements. Optionally, the first and second engagement portions may be provided in the form of a first and a second lower wall of a first groove and a second groove, respectively, of the first and second floor elements. Thereby, a displacement of a connecting portion against a respective engagement portion, such as during a displacement of the displaceable portion, may be facilitated. 
     Each floor element may comprise a first and a second engagement portion which may be arranged at different positions along its transverse direction. Preferably, the first and second engagement portions are arranged at opposite sides of the floor element. Each engagement portion may extend along the longitudinal direction for cooperating with a respective connecting portion. 
     Furthermore, the edge portion of the first floor element and the edge portion of the second floor element may face each other when the first and second floor elements are connected. 
     The displaceable portion may be horizontally displaceable with respect to a body portion of the connecting device. 
     Generally, a first and/or a second side portion of the connecting device may comprise the displaceable portion. 
     A first and/or a second side portion of the connecting device may form the displaceable portion, for varying, preferably decreasing, a relative distance between the first and second side portions. The first and/or second side portion may be displaceable towards and away from the second and/or first side portion, respectively. 
     The displaceable portion may be horizontally displaceable by virtue of being flexible or elastic. The displaceable portion may be more flexible than the body portion. 
     The displaceable portion may be compressible. 
     The body portion may comprise a portion that is horizontally fixed, in particular immobile, when the displaceable portion is horizontally displaced. 
     A portion of the body portion may be configured to be fixed with respect to a support member when the connecting device is connected, preferably removably connected, thereto. The body portion may comprise a bottom portion and, optionally, a first and/or a second side portion of the connecting device. The body portion may be fixed transversely and/or longitudinally to the support member. 
     The connecting device may be configured to assume a first and a second horizontal state, a horizontal extension of the connecting device in the second horizontal state being smaller than a horizontal extension of the connecting device in the first horizontal state. 
     A horizontal extension of the connecting device in each of the first and second horizontal states may be an extension or a length along the width direction. 
     The connecting device may be compressible at least along a horizontal direction, such as the width direction. For example, the connecting device may be compressible along the horizontal direction only. The connecting device may be configured to transition from the first horizontal state to the second horizontal state by horizontally compressing the connecting device by displacing the displaceable portion. The connecting device may be configured to be horizontally compressed by horizontally displacing the first and second floor elements relatively towards each other. 
     The connecting device may be configured to return partly or, preferably completely, from the second horizontal state to the first horizontal state. In particular, the connecting device may be configured to return partly or, preferably completely, to an initial, uncompressed state of the connecting device when the connecting device is no longer compressed. Thereby, the connecting device, in particular the displaceable portion, may remain intact, without being damaged. For example, it may be re-used. 
     The first and second connecting portions may be provided at the same, or substantially the same, height along the vertical direction in the first horizontal state. In some embodiments, however, they are provided at different heights. This may guide a user to install the connecting device correctly. In a first example, the first connecting portion is provided above the second connecting portion. In a second example, the first connecting portion is provided below the second connecting portion. 
     The first and second connecting portions may join and/or extend outwards from a first and a second side portion of the connecting device, respectively. 
     The first and second connecting portions may be horizontally fixed, in particular immobile, with respect to each other when the displaceable portion is horizontally displaced. 
     The body portion may comprise the first and/or the second connecting portion. In non-restrictive examples, the displaceable portion may be provided below the first and/or the second connecting portion. 
     The first and second connecting portions may be displaced horizontally with respect to each other when the displaceable portion is horizontally displaced. 
     The displaceable portion may comprise the first and/or the second connecting portion. 
     The horizontal extension of the connecting device in each of the first and second horizontal states may be: a maximal horizontal extension of the connecting device, such as at a top portion thereof, or a horizontal extension, such as a maximal horizontal extension, between a first abutment portion and a second abutment portion configured to abut the first and second floor elements, respectively, in the first horizontal state, the first and second abutment portions extending at least in a vertical direction, or a horizontal extension between the displaceable portion, such as an outermost surface thereof along a width direction, and a fixed surface of the connecting device, such as a first or a second protrusion, such as an outermost surface thereof along a width direction. 
     A ratio R between the horizontal extension of the connecting device in the second horizontal state and the horizontal extension of the connecting device in the first horizontal state may be less than or equal to 0.95, preferably less than or equal to 0.9, and more preferably less than or equal to 0.85. In non-limiting examples, the ratio R may be less than or equal to 0.80, or even less than or equal to 0.70. 
     The first and second floor elements may be vertically connected in the first horizontal state, and in the second horizontal state a strength of a vertical connection of a pair of floor elements in the flooring system may be reduced compared to a strength of the vertical connection of said pair of floor elements in the first horizontal state. For example, said pair of floor elements may be vertically disconnected in the second horizontal state. Additionally or alternatively, at least one floor element in the pair of floor elements may be removable in the second horizontal state, such as by angling and/or by a vertical displacement of the respective floor element. 
     The vertical connection of a pair of floor elements, for example comprising the first and second floor elements, may comprise a vertical connection between a floor element in said pair, such as the first floor element, and the connecting device. Alternatively, or additionally, the vertical connection of the pair of floor elements may comprise a vertical connection between the other floor element in said pair, such as the second floor element, and the connecting device. The connecting device may in turn be connected to a support member as described elsewhere in this disclosure. 
     A vertical disconnection of a pair of floor elements, for example comprising the first and second floor elements, may comprise a vertical disconnection between at least one floor element in said pair, such as the first floor element and/or the second floor element, and the connecting device. 
     In a first example, the vertical connection of a pair of floor elements may be reduced by providing the connecting device in the second horizontal state per se. In a second example, at least one floor element may, in addition, be displaced for reducing the vertical connection of a pair of floor elements. 
     The pair of floor elements may comprise the first floor element and a floor element adjacent to the first floor element, such as the second floor element which is adjacent to the edge portion of the first floor element or a floor element adjacent to an opposite edge portion of the first floor element. 
     The pair of floor elements may comprise the second floor element and a floor element adjacent to the second floor element, such as the first floor element which is adjacent to the edge portion of the second floor element or a floor element adjacent to an opposite edge portion of the second floor element. 
     In some embodiments, a strength of the vertical connection of two pairs of floor elements in the flooring system may be reduced in the second horizontal state compared to a strength of the vertical connection of said two pairs of floor elements in the first horizontal state. For example, said two pairs of floor elements may be vertically disconnected in the second horizontal state. Additionally or alternatively, at least one floor element in the two pairs of floor elements may be removable in the second horizontal state, such as by angling and/or by a vertical displacement of the respective floor element. As indicated above, at least one floor element might have to be displaced for achieving the reduction of the vertical connection. 
     In a first example, a first pair may consist of the first and second floor elements and a second pair may consist of the first floor element and a floor element adjacent to an opposite edge portion of the first floor element. Optionally, a strength of the vertical connection of a third pair of floor elements may be reduced in the second horizontal state compared to a strength of the vertical connection of said third pair in the first horizontal state. For example, said third pair of floor elements may be vertically disconnected in the second horizontal state. Additionally or alternatively, at least one floor element in the third pair of floor elements may be removable in the second horizontal state, such as by angling and/or by a vertical displacement of the respective floor element. For example, the third pair of floor elements may consist of the second floor element and a floor element adjacent to an opposite edge portion of the second floor element. 
     In a second example, a first pair may consist of the first and second floor elements and a second pair may consist of the second floor element and a floor element adjacent to an opposite edge portion of the second floor element. 
     In a non-limiting embodiment, the strength of the vertical connection of the first and second floor elements may be provided by a cooperation, such as a contact area, between the second engagement portion and the second connecting portion. Thus, the contact area may be smaller in the second horizontal state than in the first horizontal state. Alternatively, or additionally, the strength of the vertical connection may be provided by a cooperation, such as a contact area, between the first engagement portion and the first connecting portion. The contact area may be smaller in the second horizontal state than in the first horizontal state. In particular, the floor elements may be vertically disconnected when the second engagement portion and the second connecting portion disengage, or for example completely disengage, with each other. Alternatively, or additionally, the floor elements may be vertically disconnected when the first engagement portion and the first connecting portion disengage, or for example completely disengage, with each other. 
     Each of said contact areas may be reduced by a relative displacement of the respective engagement portion and connecting portion and/or by the connecting portion in the second horizontal state being angled with respect to the engagement portion as compared to the first horizontal state. 
     In non-restrictive examples, a ratio of the respective strengths T S2 , T S1  of the vertical connection in the second horizontal state and the first horizontal state may be 0≤T S2 /T S1 ≤0.8, preferably 0≤T S2 /T S1 ≤0.5, or more preferably 0≤T S2 /T S1 ≤0.2. For example, T S , and hence T S2 , T S1 , may represent a contact area, e.g., as described above. Indeed, the contact area may be a contact area between first engagement portion and the first connecting portion and/or a contact area between second engagement portion and the second connecting portion. 
     In the second horizontal state, a lower part of one floor element, such as a first lip, may be horizontally spaced from the connecting device. Thereby, the floor element may be removed without contacting the connecting device. 
     The first and second floor elements may also be horizontally connected in at least a first direction, such as in the transverse direction. For example, the edge portion of the second floor element, such as the first lip, may engage with the second side portion, such as the second abutment portion, and/or the edge portion of the first floor element, such as the second lip, may engage with the first side portion, such as the first abutment portion. By these engagements, a displacement of the first and/or second floor elements towards each other may be counteracted or even made impossible. Typically, however, a small displacement may be conceivable, due to an intrinsic flexibility of the connecting device. 
     Moreover, a displacement of the first and second floor elements away from each other may be counteracted or even made impossible. A similar engagement as described for the first and second floor elements may be conceivable between an opposite edge portion of the first floor element and a connecting device connecting the first floor element and a floor element adjacent to the first floor element. Alternatively, or additionally, there may be a similar engagement between an opposite edge portion of the second floor element and a connecting device connecting the second floor element and a floor element adjacent to the second floor element. 
     The first and/or second floor elements may also be horizontally connected to the connecting device per se, such as along the longitudinal direction, by friction connections. This may be implemented by the cooperation between the first and the second connecting portions and the first and the second engagement portions, respectively. 
     The cooperation between the first and the second connecting portions and the first and the second engagement portions, respectively, may be pretensioned. For example, a vertical distance from a bottom portion of the connecting device to the first and/or the second connecting portion may be smaller than a vertical distance from an underside of the respective floor element to the first and/or the second engagement portion. 
     The connecting device may further comprise a locking device for locking the connecting device in the second horizontal state. Thereby, the connecting device may remain in a compressed state, such as the second horizontal state, even after a compression force is no longer applied. This may simplify a removal of a floor element. 
     At least a part of the locking device may be provided on the displaceable portion. 
     The locking device may comprise a first and a second locking element configured to cooperate with each other, such as by a snapping engagement. The first and the second locking elements may be provided on a first and a second arm portion of the connecting device, respectively. Preferably, the first and second arm portions extend horizontally towards each other. 
     The first and the second locking elements may each comprise a sliding surface, each preferably being at least partly planar, configured to slide against each other when the connecting device transitions from the first to the second horizontal state. 
     The first and the second locking elements may be provided as hook elements. 
     The connecting device may comprise a contact portion configured to contact the displaceable portion. 
     The first arm portion and the second arm portion may be connected to each other by a breaking portion. More generally, the displaceable portion may be connected to the contact portion of the connecting device by a breaking portion. For example, the first and second locking elements may be connected to each other by a breaking portion. The breaking portion may be configured to be broken during removal of a floor element, such as when the first and second floor elements are displaced towards each other. 
     The displaceable portion and the contact portion may be provided with a resistance element. For example, the first and the second locking elements may be provided with a resistance element. 
     The locking device may be configured to be unlocked from the second horizontal state by compressing, preferably horizontally compressing, the connecting device and/or by displacing a first arm portion of the connecting device away from a second arm portion of the connecting device, such as by a vertical displacement and/or an angling thereof. For example, the displaceable portion may be displaced. 
     The connecting device may comprise a guiding surface, optionally joining a second locking element of the locking device of the connecting device for locking the connecting device in the second horizontal state. 
     The displaceable portion may comprise an arm portion, such as a first arm portion. The arm portion may be configured to vary, preferably decrease, a relative distance between the arm portion and the first and/or the second side portion. 
     The arm portion may be a first arm portion and the connecting device may further comprise a second arm portion, the first and the second arm portions preferably extending horizontally towards each other. 
     The arm portion may be provided in a first or a second side portion, preferably comprising a first portion extending at least partially in a direction away from a wall portion of the first or second side portion and optionally further comprising a second portion extending at least partially in a direction towards the wall portion. 
     The arm portion may comprise at least two arms, preferably extending at least partially towards a first side portion and preferably being provided symmetrically around a centre line extending along a width direction. 
     The connecting device may comprise a barrier member configured to prevent the displaceable portion, such as an arm portion, from being displaced beyond an obstruction element. The obstruction element may be a contact portion of the connecting device. For example, the obstruction element may be at least a portion of a wall portion of the connecting device. 
     The barrier member may comprise a first barrier element and a second barrier element configured to cooperate with the first barrier element, wherein the first barrier element preferably is provided in the displaceable portion and the second barrier element preferably is provided in a first side portion of the connecting device, such as in a wall portion thereof. 
     The second barrier element may comprise a pocket configured to receive at least a portion of the first barrier element. 
     The displaceable portion may be configured to be displaced beyond the obstruction element when a compression force exceeding a threshold value is applied. 
     The first and second connecting portions may be provided on a first and a second protrusion of the connecting device, respectively. The first and second protrusions may extend along the width direction of the connecting device. Each of the first and second protrusions may extend in a direction away from a centre portion of the connecting device. 
     The connecting device may comprise a top portion comprising the first and second protrusions. 
     The connecting device may comprise a first abutment portion and/or a second abutment portion configured to abut the first and/or second floor elements in the first horizontal state, the first and second abutment portions extending at least in a vertical direction. The first and the second abutment portion may be provided in a first and a second side portion of the connecting device, respectively. 
     In the first horizontal state, the first abutment portion may engage with a first lip of the first floor element, and/or the second abutment portion may engage with a first lip of the second floor element. The first and/or the second abutment portion may be configured to be spaced from the first and/or second floor elements in the second horizontal state, such as spaced from the first lip of the first and/or second floor elements. 
     The first and/or the second abutment portion may comprise at least one curved abutment surface. 
     The first or the second abutment portion may be provided on an arm portion, such as a first arm portion. 
     The connecting device may be flexible, preferably along the width direction. Thereby, the floor elements may be displaced towards each other. A first section of the connecting device may be more flexible, preferably horizontally flexible, than a second section of the connecting device, wherein the first section preferably is provided adjacent to the second floor element and the second section preferably is provided adjacent to the first floor element when the first and second floor elements are connected. The horizontal flexibility may be provided along the width direction of the connecting device. 
     The first section may comprise the displaceable portion. Moreover, the second section may comprise the body portion. 
     A connecting device, such as a flexible connecting device, may be compressed and may return partly or, preferably completely, to an initial, uncompressed state of the connecting device when the connecting device is no longer compressed. 
     It is understood that in some embodiments the second section may be more flexible than the first section. 
     The first and second engagement portions may be provided in a first groove and a second groove, respectively, of the first and second floor elements. 
     The edge portion of each of the first and second floor elements may comprise a first and a second lip provided below and above the first and the second groove of the first and second floor elements, respectively. 
     The second lip of the first floor element may extend horizontally beyond the first lip of the first floor element, and/or the second lip of the second floor element may extend horizontally beyond the first lip of the second floor element. 
     The second lip of the second floor element may comprise a prominence extending beyond an uppermost portion of the edge portion of the second floor element. 
     The second lip of the first floor element and the prominence may at least partially overlap each other in a horizontal plane being parallel with a top side and/or an underside of each floor element. 
     In exemplary embodiments, the features of the edge portion, such as their lip configurations, of each of the first and second floor elements described above may be interchanged. 
     A cross-sectional profile of each floor element may be the same along the longitudinal direction of the floor element. Thereby, a cross-sectional profile of at least one selected from the group of the first groove, the second groove, the first protrusion, and the second protrusion, may be the same along the longitudinal direction. 
     The first and second floor elements may be configured to conceal the connecting device when the floor elements are connected, preferably such that edge portions of the first and second floor elements at least partially overlap each other in a horizontal plane being parallel with a top side and/or an underside of each floor element. 
     The connecting device may be visible when the first and second floor elements are connected. Outermost adjacent portions of the first and second floor elements may be spaced from each other. 
     The connecting device may comprise a protruding element configured to be provided in the first groove, the first groove optionally comprising a recess for accommodating at least a portion of the protruding element. The connecting device may thereby be transversely connected to the first floor element. The protruding element may at least extend vertically upwards. Moreover, the recess may be open downwards in the first groove. The protruding element may be configured to be provided in the first groove in the first and/or the second horizontal state. By virtue of the protruding element, the connecting device may be positioned horizontally with respect to the first floor element. Moreover, the connecting device may be held in position, especially during installation of the floor elements. 
     The connecting device may comprise a friction element, preferably provided in a cavity of the connecting device, and being configured to engage with a floor element, such as the first floor element, in the first horizontal state. For example, the friction element may engage with the first lip of the first floor element, such as with a first lip surface of the first lip. Thereby, the connecting device may maintain an engagement with the first floor element, even under dimensional variations of the floor elements, caused e.g. by temperature or humidity fluctuations. 
     The connecting device may be configured to transition from the first horizontal state to the second horizontal state when a compression force of the connecting device exceeds a predetermined threshold value F TH . Thereby, a transverse distance between the floor elements may be controlled in an improved manner, since a force exceeding a threshold force may be required to displace the floor elements towards each other beyond a certain point. For example, the threshold value may be larger than typical forces caused by strong winds acting on the flooring system. The threshold value may be adapted to a fixed number of connecting devices connecting the first and second floor elements. In particular, a larger number of connecting devices arranged along the longitudinal extension of the floor elements may give rise to an increased resistance and hence may give rise to a smaller threshold value of an individual connecting device. In a non-limiting example, F TH  for compressing the first and second floor elements connected by at least one connecting device may be 20-500 N, such as for polymer-based connecting devices. In another non-limiting example, F TH  for compressing the first and second floor elements connected by at least one connecting device may be 100-500 N/m, such as for polymer-based connecting devices. 
     The connecting device may be provided with a non-linear spring constant along a horizontal direction, the horizontal direction preferably being parallel with a width direction of the connecting device. The non-linear spring constant may be dependent on a degree of compression of the connecting device along the width direction. 
     A non-linear behavior of the connecting device may be activated by a pair of engaging elements of the connecting device configured to engage with each other during compression of the connecting device. For example, the engaging elements may be a respective sliding surface of the first and second locking elements or a first and a second barrier element of the connecting device. 
     A spring constant of the connecting device along a horizontal direction, such as the width direction, may be configured to decrease when compressing the connecting device from a first compression level to a second compression level. Thereby, a risk of an accidental disconnection of the connecting device may be reduced, while facilitating disconnection once such disconnection has been commenced. In a first example, the spring constant may have a linear behavior at both the first and the second compression levels. In a second example, the spring constant may have a non-linear behavior at the first compression level and a linear behavior at the second compression level. 
     The connecting device may be provided with at least a first and a second, optionally also a third, horizontal spring constant. Each horizontal spring constant may be consecutively activated. In non-limiting examples, any of said first, second, or third horizontal spring constants may be a substantially linear or a non-linear horizontal spring constant. 
     The connecting device may have a first horizontal spring constant in or close to the first horizontal state when the displaceable portion does not engage with the first and/or the second side portion, a second horizontal spring constant when transitioning from the first to the second horizontal state by being compressed, such as when the displaceable portion engages with the first and/or the second side portion, and a third horizontal spring constant when the second horizontal state has been reached or passed. 
     The connecting device may be connectable, preferably removably connectable, to a support member, such as by a fastening element provided through a hole in the connecting device. The fastening element may be a screw, a nail, or similarly. 
     Alternatively, or additionally, the connecting device may comprise a coupling portion configured to cooperate with a mounting portion of a support member, preferably by a snapping engagement. 
     The connecting device may be transversely connectable and preferably also longitudinally connectable to the support member. 
     The support member may be a joist. Moreover, the support member may be made of wood or aluminium or may be a polymer-based support member. 
     The flooring system may comprise a first set of connecting devices that are connected to the support member, such as transversely and longitudinally connected thereto, and a second set of connecting devices that are not longitudinally connected to the support member, but may optionally be transversally connected thereto. For example, at least one connecting device of the second set may be provided between a pair of connecting devices according to the first set. A connecting device of the second set may be longitudinally slidable along the support member. 
     The connecting device may be integrally formed, i.e. formed in one piece. For example, the displaceable portion may be integrally formed with the connecting device, such as with the body portion. The connecting device may comprise a single material, such as a metal, preferably steel or aluminium, or a polymer-based material. 
     In some embodiments, the displaceable portion is separately formed from the connecting device, such as from the body portion. The displaceable portion may be attached to the first or the second side portion, such as a wall portion thereof, e.g. by an attaching element. For example, the attaching element may be a snapping element or may comprise a tongue and tongue slot configuration. The connecting device may comprise a first material, such as a metal, such as steel, or a polymer-based material, and a second material, such as a polymer-based material. The separately formed displaceable portion may comprise the first material and the body portion may comprise the second material. The body portion may be a remainder of the connecting device to which the displaceable portion may be attached. 
     In the embodiments of the integrally formed as well as the separately formed connecting devices above the polymer-based material may be polyamide (PA), such as type 6 or 66, polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polyurethane (PU), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), or thermoplastic elastomer (TPE). 
     At least the body portion of the connecting device, or optionally the entire connecting device, may be extruded, injection moulded, 3D-printed, 3D-printed in powder, etc. Moreover, at least the body portion may comprise a reinforcement material, such as a glass-fibre material. 
     According to a second exemplary aspect of the inventive concept, there is provided a connecting device for connecting a first floor element and a second floor element. The connecting device comprises a first and a second connecting portion which are configured to cooperate—for example, engage—with a first and a second engagement portion of the first and second floor elements, respectively, for vertically connecting the first and second floor elements. The connecting device further comprises a displaceable portion which is horizontally displaceable with respect to a body portion of the connecting device, preferably along a width direction of the connecting device. 
     Embodiments and examples of the connecting device in accordance with the second aspect are largely analogous to those of the first aspect, wherein reference is made to the above. In particular, embodiments and examples of at least one selected from the group of the displaceable portion, the body portion, the contact portion, the first and second connecting portions, the first and a second protrusions, the first and second side portions, the first and second abutment portions, the first and second sections, first and/or the second arm portions, the barrier member, first and second barrier element, the pocket, the obstruction element, the locking device, the first and second locking elements, the hole, the coupling portion, the mounting portion, the protruding element, the friction element, the resistance element, the breaking portion, the separate or integral forming, the spring constant, such as the non-linear spring constant, the material, and the configurations of the first and second horizontal states, and their transitions, of the connecting device may be the same. 
     Further exemplary aspects of the inventive concept and embodiments and examples of each of the first and second aspects are provided in an “Exemplary Embodiments” section below. It is emphasized that the embodiments and examples of any aspect may be combined with embodiments and examples of any other aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will in the following be described in connection to exemplary embodiments and in greater detail with reference to the appended exemplary drawings, wherein: 
         FIGS. 1 a - c    illustrate embodiments of floor elements connected by a connecting device in side views. 
         FIGS. 2 a - e    illustrate in side views, a top view, and a perspective view embodiments of flooring systems, connecting devices, and methods of disconnecting floor elements. 
         FIGS. 3 a - f    illustrate embodiments of connecting devices in perspective views and side views. 
         FIGS. 4 a - h    illustrate embodiments of connecting devices in perspective views and side views. 
         FIGS. 5 a - e    illustrate in side views embodiments of methods of removing and installing floor elements in a flooring system. 
         FIGS. 6 a - b    illustrate in a side view and a front view an embodiment of a method of unlocking a connecting device comprising a locking device. 
         FIGS. 7 a - c    illustrate an embodiment of a connecting device in a perspective view and in a side view; the connecting device is also shown in an installed state. 
         FIG. 7 d    illustrates an embodiment of a connecting device in a perspective view. 
         FIGS. 8 a - f    illustrate an embodiment of a connecting device in perspective views, a zoomed-in perspective view, side views, and a top view. 
         FIGS. 9 a - b    illustrate top views of embodiments of a connecting device zoomed in around an end portion of a displacement portion. 
         FIG. 9 c    illustrates a side view of an embodiment of floor elements connected by the connecting device according to  FIGS. 8 a   - f.    
         FIGS. 9 d - f    disclose graphs schematically illustrating non-linear behaviors of various embodiments of the connecting device. 
         FIGS. 10 a - e    illustrate embodiments of connecting devices and their connection to a support member in a perspective view, two side views, and two front views. 
         FIG. 10 f    illustrates an embodiment of a connecting device in a perspective view. 
         FIGS. 11 a - f    illustrate embodiments of a connecting device in top views, bottom views and perspective views. 
         FIGS. 12 a - b    illustrate embodiments of floor elements connected by the connecting device according to any of  FIGS. 11 a - f    in a side view and a perspective view. 
     
    
    
     DETAILED DESCRIPTION 
     Next, embodiments of flooring systems and connecting devices will be described with reference to  FIGS. 1 a - c , 2 a - e , 3 a - f , 4 a - h , 5 a - e , 6 a   - b ,  7   a - d ,  8   a - f ,  9   a - f ,  10   a - f ,  11   a - f  and  12   a - b . Preferably, the flooring system is a decking system, but other flooring systems—preferably for outdoor applications—are equally conceivable, such as flooring systems for verandas, terraces or the like. 
       FIGS. 1 a - c    are side views of embodiments of a flooring system comprising a set of, preferably essentially identical, floor elements comprising a first  100  and a second  200  floor element. The flooring system further comprises a connecting system comprising a connecting device  300  for connecting the floor elements  100 ,  200 . The floor elements may be decking elements, such as decking panels. 
     The first  100  and second  200  floor elements each comprise an edge portion  110 ,  210 , a top side  101 ,  201 , and an underside  102 ,  202 . As illustrated in the embodiment in  FIG. 2 e   , each of the first and second floor elements also comprises an opposite edge portion  114 ,  214  which preferably is essentially identical to the edge portion  210 ,  110  of the second and the first floor elements, respectively. 
     The edge portion  110  of the first floor element comprises a first groove  120 . A first lip  130  and a second lip  140  are provided below and above the first groove, respectively. The second lip  140  extends horizontally beyond the first lip  130 . 
     The edge portion  210  of the second floor element comprises a second groove  220 . A first lip  230  and a second lip  240  are provided below and above the second groove, respectively. The second lip  240  extends horizontally beyond the first lip  230 . 
     Optionally, a lower wall  133 ,  233  of the first lip  130  and/or the first lip  230  may comprise an inclined surface  131 ,  231 . Moreover, an underside  144 ,  244  of any of the second lips  140 ,  240  may be inclined with respect to the respective top side  101 ,  201 . 
     The first and second grooves  120  and  220  comprise a first  122  and a second  222  engagement portion, respectively. In the present embodiment, the first and second engagement portions are provided in the form of a first  123  and a second  223  lower wall of the respective first groove. Each lower wall  123 ,  223  may comprise at least a partially planar portion which, preferably, is essentially parallel with the top side  101 ,  201  and/or the underside  102 ,  202 . More generally, the first  122  and/or the second  222  engagement portion may extend essentially in parallel with the top side  101 ,  201  and/or the underside  102 ,  202  of the floor elements. The lower walls  123  and  223  may be an upper wall of the first lips  130  and  230 , respectively. 
     According to a preferred embodiment, there is a space  10  between upper parts of the edge portions  110 ,  210 . In the embodiment shown in  FIG. 1 a   , the second lip  240  comprises a prominence  242  extending beyond an uppermost portion  212  of the edge portion  210 . The second lip  140  of the first floor element and the prominence  242  may at least partially overlap each other in a horizontal plane HP which is parallel with the top side  101 ,  201  and/or the underside  102 ,  202 . The horizontal plane HP extends in a transverse direction X and in a longitudinal direction Y of the floor elements. Thereby, the connecting device may be concealed from above when the floor elements are connected. In one example, and as illustrated in  FIG. 1 a    and in a top view of the floor elements in  FIG. 2 a   , the overlap may be an overlap OL between a projection of each the second lip  140  and the prominence  242  onto the horizontal plane HP. The second lip  140  and the prominence  242  may be vertically spaced by a separation Q where they overlap. In some embodiments, and as shown e.g. in  FIG. 1 c   , the separation Q, such as a minimal separation in the overlap OL, is larger than or equal to the space  10 , such as a minimal space, between the upper parts. Thereby, debris, dirt or the like having a maximal extension that is smaller than or equal to the space  10  may fall down between floor elements  100 ,  200  more easily. 
     Preferably, the grooves  120 ,  220  and the lips  130 ,  140 ,  230 ,  240  extend along the entire longitudinal direction Y of the first and second floor elements, respectively. 
       FIGS. 3 a  and 3 b    illustrate an embodiment of the connecting device  300  in a perspective view and a side view, respectively. The connecting device extends in a width direction W, a depth direction D, and in a vertical direction V which is perpendicular to the width and depth directions. The vertical direction V may be perpendicular to the horizontal plane HP when the floor elements are connected. 
     Preferably, the connecting device comprises a single material, such as a polymer-based material or a metal, preferably steel. 
     The connecting device comprises a first  330  and a second  340  protrusion comprising a first  332  and a second  342  connecting portion, respectively. The first and second protrusions each extend in a direction away from a centre portion CP of the connecting device along the width direction W, cf.  FIG. 4 b   . In  FIGS. 3 a - b   , the first and second connecting portions are provided in the form of a first  333  and a second  343  bottom surface of the first  330  and the second  340  protrusions, respectively. Each bottom surface  333 ,  343  may comprise at least a partially planar portion which may be essentially parallel with the lower walls  123  and  223  when the floor elements are connected. More generally, the first connecting portion  332  and/or the second connecting portion  342  may include a respective surface, such as the bottom surface  333 ,  343 , that is essentially parallel to the top side  101 ,  201  and/or the underside  102 ,  202  of the floor elements. 
     The first and the second connecting portions are configured to cooperate—for example, engage—with the first  122  and the second  222  engagement portions, respectively, for vertically connecting the first and second floor elements. 
     According to preferred embodiments, the connecting device is removably connectable to a support member  500 . In some embodiments, and as shown in  FIG. 1 a   , a fastening element  400 , e.g. in the form of a screw, is provided through a hole  352  (illustrated in  FIG. 3 a   ) in the connecting device and fastened to the support member. The hole  352  is provided in a bottom portion  350  of the connecting device. Other embodiments of removably connectable connecting devices and associated support members are described further below in relation to  FIGS. 10 a - f , 11 a - f  and 12 a - b    and are equally conceivable instead of a fastening element  400  and a hole  352 . In fact, in some embodiments the connecting device may even be permanently fixed to the support member. For simplicity of presentation, the support member  500  and/or a corresponding mechanism for connecting the connecting device to the support member, such as the fastening element  400  or mounting portion  510 , will often be suppressed in the embodiments shown in the figures of this disclosure, but their presence may be implicitly understood. 
     In the embodiment of  FIGS. 3 a - b   , the connecting device further comprises a first  310  and a second  320  arm portion extending horizontally towards each other. The first arm portion  310  may comprise an opening  312  which may be at least partly, or optionally completely, aligned with the hole  352  when projected in the horizontal plane HP. Thereby, the hole  352  may be accessed through the opening  312 , e.g. by a tool, such as a screw driver. An area of the opening may be larger than an area of the hole. 
     Preferably, the first and second arm portions at least partially extend along each other in the depth direction D. In some embodiments, the first and second arm portions entirely extend along each other as shown in  FIG. 3   a.    
     The connecting device is configured to assume a first horizontal state S 1  and a second horizontal state S 2 . A horizontal extension L 2 , L 2 ′ of the connecting device in the second horizontal state S 2  is smaller than a horizontal extension L 1 , L 1 ′ of the connecting device in the first horizontal state S 1 , see  FIGS. 3 b    and  3   d.    
     The connecting device further comprises a first  360  and a second  370  side portion comprising a first  362  and a second  372  abutment portion, respectively. The protrusions  330  and  340  join and/or extend outwards from the first and the second side portions, respectively. The first and second abutment portions are configured to abut the first  100  and second  200  floor elements, preferably the first lips  130  and  230 , respectively, in the first horizontal state S 1 . The first and second abutment portions extend at least in the vertical direction V and preferably also in the depth direction D. In examples, the first and/or second abutment portion may extend substantially vertically. The first side portion  360  may extend vertically from the bottom portion  350  and may join the second arm portion  320 . Moreover, the second side portion  370  may join the first arm portion  310 . The second side portion may further comprise an inclined portion  374  extending from the bottom portion  350  and joining the second abutment portion  372 . An angle θ between the bottom portion and the inclined portion may be between 15° and 75°, such as between 25° and 65° or between 40° and 50°. 
     The second side portion  370  may form a displaceable portion  316  which is horizontally displaceable with respect to a body portion  314  of the connecting device, preferably along the width direction W. Thereby, a relative distance between the first  360  and second  370  side portions may be varied, preferably decreased. A portion of the body portion may be fixed with respect to the support member  500  when the connecting device is connected thereto, and may comprise the bottom portion  350  and, optionally, the first side portion  360 . 
     Alternatively, or additionally, the displaceable portion  316  may comprise the first side portion  360  which may be horizontally displaceable with respect to the body portion  314 , preferably along the width direction W. In these embodiments, the body portion may comprise the bottom portion  350  and, optionally, the second side portion  360 . 
     Preferably, the first and second protrusions, and hence the first  332  and second  342  connecting portions are horizontally displaceable with respect to each other, such as when the displaceable portion  316  is horizontally displaced. 
     An extension of the first and/or the second connecting portion from the respective side portion  360 ,  370  along the width direction W may be smaller than or substantially equal to the space  10 , such as a minimal space, between the upper parts of the edge portions  110 ,  210 . Thereby, the removal of a floor element may be facilitated as shown in e.g. in the embodiment in  FIGS. 5 a   - c.    
     In some embodiments, a shape of a first lip surface  132  and a second lip surface  232  of the first lips  130 ,  230  corresponds to a shape of the first  362  and the second  372  abutment portions, respectively. The first and/or the second lip surface may extend essentially vertically. 
     As shown in  FIGS. 3 a - f   , the connecting device may comprise a locking device  380  for locking the connecting device in the second horizontal state S 2 . The locking device comprises a first  382  and a second  384  locking element provided on the first  310  and the second  320  arm portion, respectively, preferably at a respective end portion thereof. The locking elements are configured to cooperate with each other, such as by a snapping engagement, and they may be provided as hook elements. 
     Moreover, the first and second locking elements may comprise a respective sliding surface  381 ,  383 , which preferably are at least partially planar. In some embodiments, each of the sliding surfaces  381 ,  383  comprises a first planar portion  381   a ,  383   a  and a second planar portion  381   b ,  383   b  as indicated in  FIG. 3 c   . The sliding surfaces  381 ,  383  may be configured to slide against each other when the connecting device transitions from the first S 1  to the second S 2  horizontal state. 
     There may be a gap  11  between the first  310  and the second  320  arm portion in the first horizontal state S 1 . In some embodiments, however, there may be contact between said arm portions in the first horizontal state S 1 . 
     Optionally, and as shown in  FIGS. 1 a - b , 2 a - d , 3 e - f    the connecting device may comprise a wall element  390  whose characteristics will be described further below. 
     The connecting device may comprise a contact portion  391  configured to contact the displaceable portion  316 . In non-limiting examples, the displaceable portion  316  may comprise the first arm portion  310  and the contact portion  391  may comprise at least one selected from the group of the second arm portion  320 , the wall element  390  and the sliding surface  381 ,  383 . 
     The locking device  380  may be unlocked in the first horizontal state S 1 , see e.g.  FIGS. 1 a - c , 2 a , 2 c , 3 a - b , 3 e - f  and 4 a - h   . Furthermore, the locking device may be locked in the second horizontal state S 2 , see e.g.  FIGS. 2 b , 2 d  and 3 c   - d.    
     As illustrated in  FIGS. 2 a - d  and 3 a - d   , and also in  FIGS. 8 a - f  and 11 a - f   , a horizontal extension L 2 , L 2 ′ of the connecting device in the second horizontal state S 2  is smaller than a horizontal extension L 1 , L 1 ′ of the connecting device in the first horizontal state S 1 . In some embodiments, and as shown in  FIGS. 2 c - d , 3 b , 3 d  and 11 f   , the horizontal extension in the first S 1  and second S 2  horizontal states is a horizontal extension, preferably a maximal horizontal extension, L 1 , L 2  of the connecting device, such as at a top portion  318  thereof. In some embodiments, and as shown in  FIGS. 2 a - d  and 8 a - f   , the horizontal extension in the first S 1  and second S 2  horizontal states is a horizontal extension, preferably a maximal horizontal extension, L 1 ′, L 2 ′ between the first  362  and the second  372  abutment portion. In some embodiments, and as shown in  FIGS. 2 c - d , 8 d , 8 f  and 11 c   , the horizontal extension in the first S 1  and second S 2  horizontal states is a horizontal extension L 1 ″, L 2 ″ between the displaceable portion  316 , such as an outermost surface thereof along the width direction W, and a fixed surface of the connecting device, such as the first  330  or the second  340  protrusion, such as an outermost surface thereof along the width direction W. In  FIGS. 8 d  and 8 f    the fixed surface may be provided in the first abutment portion  362 . In any embodiment of the present disclosure, especially in  FIGS. 8 a - f  and 11 a - f   , the fixed surface may be provided in the contact portion. 
     The connecting device may be configured to transition from the first S 1  to the second S 2  horizontal state by horizontally compressing the connecting device along the width direction W, such as by horizontally displacing the first  100  and second  200  floor elements relatively towards each other along the transverse direction X as illustrated in the embodiments in  FIG. 2 a    and  FIG. 2 e   . In  FIG. 2 e   , a respective gripping portion  602 , such as a hooked gripping portion, of a first and a second displacement tool  600  is provided in contact with the opposite edge portions  114  and  214 , respectively, preferably with upper parts thereof, such as around the second lips  240  and  140 . In some embodiments (not shown), other displacement tools  600  may be utilized. For example, a lever device, such as at least one crowbar, may be provided between a space  10  between the opposite edge portions  114  and  214  of the first and second floor elements, respectively, and a respective adjacent floor element, and the first  100  and second  200  floor elements may be horizontally displaced relatively towards each other by levering or bending the lever device against the respective adjacent floor element. 
     It is understood that in some embodiments there may be at least one floor element, such as one, two or three floor elements, between the first and second displacement tools  600 . Thereby, a pair of transversely outermost floor elements in a set of at least three floor elements may be displaced relatively towards each other for accomplishing a transition from the first S 1  to the second S 2  horizontal state of a connecting device provided between a pair of floor elements in the set of at least three floor elements. 
     Alternatively, or additionally, the first and second floor elements or a pair of transversely outermost floor elements in a set of at least three floor elements may be displaced relatively towards each other by other displacement tools  600 , such as an arrangement of straps, ratchet straps, clamps, or similarly, around a portion of the floor elements, or around them, and then tightening the arrangement. 
     In a first example, and as indicated by the arrow M 1  in  FIG. 2 a   , only the first floor element is displaced. In a second example, and as indicated by the arrow M 2 , only the second floor element is displaced. In a third example, and as indicated by the arrows M 1  and M 2 , both the first and the second floor elements are displaced. As noted above, in some embodiments the displacement of the adjacent first and second floor elements described in any of the examples above may be replaced by a displacement of a pair of transversely outermost floor elements in a set of at least three floor elements. 
     Contact between the floor elements, such as upper parts of the floor elements  100 ,  200 , may prevent the connecting device from being further compressed. 
     The connecting device  300  may transition from the second horizontal state S 2  back to the first horizontal state S 1 . The locking device  380  may be unlocked from the second horizontal state S 2  by compressing, preferably horizontally compressing, e.g. along the width direction W, the connecting device and/or by displacing the displaceable portion  316  away from the contact portion  391 , e.g. displacing the first arm portion  310  away from the second arm portion  320 , such as by a vertical displacement and/or an angling thereof, see the arrows A 0 , V 0  in  FIG. 3   d.    
     Here, and in any other embodiment of the disclosure, the second horizontal state S 2  may be a state such that a ratio R=L 2 /L 1  between the horizontal extension L 2 , L 2 ′, L 2 ″ in the second horizontal state and the horizontal extension L 1 , L 1 ′, L 1 ″ in the first horizontal state is less than or equal to a critical ratio R crit . For example, R crit  may be 0.95, preferably 0.9, and more preferably 0.85. 
     The connecting device may extend only along a portion of the first and second floor elements along their longitudinal direction Y. Preferably, there are a plurality of connecting devices arranged along the longitudinal direction Y for connecting the first and second floor elements. Any embodiment of the connecting device and the first and second floor elements described in the present disclosure is also applicable as embodiments of the plurality of connecting devices. 
     With reference to e.g.  FIG. 3 b   , the connecting device  300  may comprise a first  301  and a second  302  section that are configured to be adjacent to the second  200  and first  100  floor element, respectively, when the first and second floor elements are connected. The first and the second sections may both be flexible, preferably at least horizontally flexible, e.g. along the width direction W. In a first embodiment, the first section  301  is more horizontally flexible, preferably along the width direction W, than the second section  302 . In a second embodiment, the second section  302  is more horizontally flexible, preferably along the width direction W, than the second section  301 . In any of these embodiments, the displaceable portion, such as the first arm portion, may be displaced more easily than the contact portion, such as the second arm portion, when the connecting device is horizontally compressed. 
     Preferably, an entire portion extending along the depth direction D of each of the first  301  and second  302  sections are displaceable. 
     In some embodiments, the connecting device comprises a protruding element  322 . In the embodiments shown in  FIGS. 3 a - f  and 4 a - f    the protruding element  322  is provided on the second arm portion  320 , and preferably extends upwards therefrom. In the connected state, the protruding element may be provided in the first groove  120  as shown in  FIGS. 1 a  and 2 a - b   . In some embodiments, the first groove comprises a recess  124  for accommodating at least a portion of the protruding element. 
     The protruding element  322  may extend along a portion or portions of the connecting device along the depth direction D as illustrated in  FIGS. 3 a - d  and 4 e - f   . For example, the protruding element may be provided at end portions of the connecting device along the depth direction D. In some embodiments, the protruding element may extend along the entire connecting device along the depth direction D as illustrated in  FIGS. 3 e - f  and 4 a   - d.    
     Optionally, the second arm portion  320  may comprise a notch element  324  as illustrated in e.g.  FIGS. 1 a , 2 a - b , 3 a - d  and 4 e - f   . The notch element may extend along the depth direction D at least along a portion of the connecting device, such as alongside of a corresponding protruding element  322 . By virtue of the notch element  324 , the second arm portion  320 , and in particular the protruding element  322 , may be vertically compressed and thereby may reduce its vertical extension. This may simplify an insertion of the second arm portion  320  into the first groove  120  and/or an insertion of the protruding element into the recess  124 . 
     As illustrated in e.g.  FIGS. 1 a - b , 2 a - d , 3 e - f , 4 a - f , and 7 a - c   , the connecting device may in some embodiments comprise a wall element  390 . The wall element may extend from the bottom portion  350  and may join the first protrusion  330  and/or, when present, the second arm portion  320 . The wall element may make portions of the connecting device stiffer. 
     The wall element  390  may comprise a guiding surface  385  which joins the second locking element  384 , such as along the sliding surface  383 , as illustrated in e.g.  FIGS. 3 e - f , 4 a - f  and 7 a - b   . The guiding surface  385  may be configured to guide an elongated, preferably flexible, element  620 , such as a string or a cord, inserted between the wall element  390  and the second side portion  370  towards the second locking element  384  as may be seen in the embodiment in  FIG. 5 b   . Alternatively, or additionally, an inner surface  388  of the first arm portion  310  may be a guiding surface  385 ′ for guiding the elongated element  620 . 
     The wall element  390  may comprise a vertical portion  392  extending essentially vertically from the bottom portion  350 . Optionally, a portion of, or even the entire, vertical portion  392  may be an inclined portion  394 , which preferably comprises a planar surface. A portion of the sliding surface  381  may be an upper surface portion  395  of the vertical portion  392 , such as the inclined portion  394 . Optionally, a planar portion of the upper surface portion may be essentially parallel with a planar portion of the sliding surface  383  as shown in  FIG. 3   f.    
     In some embodiments, the connecting device may comprise a friction element  364 . The friction element may comprise a flexible and/or compressible material. The friction element may comprise a polymer-based material, such as PVC, and preferably comprising plasticizer, an elastoplastic material, or a rubber, preferably a cross-linked rubber, such as an EPDM rubber. In the embodiment illustrated in  FIGS. 4 c - d   , the friction element  364  is provided in a cavity  366  provided in the first side portion  360 . Moreover, the friction element may be configured to engage with the first floor element  100 , such as the first lip  130 , in the first horizontal state S 1 . For example the friction element may engage with the first lip surface  132 . The horizontal extension in the first S 1  and second S 2  horizontal states may be a horizontal extension, preferably a maximal horizontal extension, L 1 ′, L 2 ′ between the second abutment portion  372  and the first abutment portion  362  or the friction element  364 , such as an outermost portion thereof. Alternatively, the horizontal extension may be a horizontal extension, preferably a maximal horizontal extension, L 1 , L 2  of the connecting device, such as at a top portion  318  thereof. 
     The connecting device may comprise a contact portion  391  configured to contact the displaceable portion  316 . The displaceable portion may be connected to the contact portion by a breaking portion  386 .  FIGS. 4 e - f    show an embodiment illustrating that the first  310  and the second  320  arm portions may be connected to each other by a breaking portion  386 . In this particular embodiment, the first  382  and the second  384  locking elements are connected to each other by a breaking portion  386 . The breaking portion connects the sliding surfaces  381 ,  383 . The breaking portion may be configured to be broken when the contact portion and the displaceable portion, such as the first and second arm portions, are displaced relative each other, preferably towards each other. In some embodiments, and as shown in  FIGS. 4 e - f   , there is a single breaking portion, preferably extending along the entire connecting device along the depth direction D. In some embodiments (not shown), there may be at least two breaking portions provided along the depth direction D and being spaced from each other. 
     In some embodiments, the displaceable portion  316  and the contact portion  391  may be provided with a resistance element  387 .  FIG. 4 a    shows an embodiment in which the first and the second locking elements are provided with a resistance element. The first and the second locking elements may comprise ribbed elements  387   a ,  387   b.    
     In some embodiments, and as illustrated in  FIGS. 1 b  and 2 c - d   , the first side portion  360  may comprise an indentation  361 . Thereby, the first abutment portion  362  may comprise a non-planar surface  363 . Furthermore, in some embodiments, and as also illustrated in  FIGS. 1 b  and 2 c - d   , the second side portion  370  comprises a protuberance  371 . Thereby, the second abutment portion  372  may comprise a non-planar surface  376 . For example, an extension of any of the non-planar surfaces  363  and  366  along the width direction W may vary along the vertical direction V. Preferably, a cross-section of the non-planar surface is constant along the entire depth extension of the connecting device. 
     In the first horizontal state S 1 , the non-planar surface  363  may abut at least one selected from the group of the lower wall  123 , an outermost portion of the first lip  130 , and the lower wall  133 , such as an inclined surface  131 . For example, all elements of this group may be selected. Moreover, in the first horizontal state S 1 , the non-planar surface  376  may abut at least one selected from the group of the lower wall  223 , an outermost portion of the first lip  230 , the lower wall  233 , such as the inclined surface  231 , and an inner wall  234  disposed inwardly of the outermost portion. For example, all elements of this group may be selected. 
     In some embodiments (not shown), the second side portion  370  may comprise an indentation  361  and/or the first side portion  360  may comprise a protuberance  371 . The characteristics of the indentation  361  and the protuberance  371  may be the same as for those described in relation to  FIGS. 1 b  and 2 c - d   , whereby reference is made to the above. 
     Other features and functionalities of the embodiments in  FIGS. 1 b  and 2 c - d    may be similar to the embodiments described elsewhere in the present disclosure, such as e.g. in  FIGS. 1 a , 1 c , 2 a - b , 2 e , 3 a - f , 4 a - h , 7 a - d   ,  8   a - f ,  9   a - f  and  10   a - f.    
     In some embodiments, and as illustrated in e.g.  FIGS. 1 a , 2 a - b , 3 a - d , 4 a - f , 7 a - d , 8 a - f   ,  9   c  and  10   b , the first  332  and second  342  connecting portions, e.g. provided in the form of a first  333  and a second  343  bottom surface, respectively, are provided at the same, or substantially the same, height along the vertical direction V in the first horizontal state S 1 . In some embodiments, and as illustrated in e.g.  FIGS. 1 b - c , 2 c - d , 3 e - f , 4 g - h   , but are equally conceivable for the other embodiments, they are provided at different heights. 
     In a similar manner, in some embodiments, the first  122  and second  222  engagement portions, e.g. provided in the form of a first  123  and a second  223  lower wall, are provided at the same, or substantially the same, height along the vertical direction V. In some embodiments they are provided at different heights. In a first example, the first engagement portion is provided above the second engagement portion. In a second example, the first engagement portion is provided below the second engagement portion. 
       FIGS. 1 c  and 4 g - h    illustrate embodiments in which the connecting device is, or comprises components preferably being made of, metal, such as steel or aluminium. The connecting device may be manufactured by bending a blank of metal. The sliding surface  381  of the second arm portion  320  may be provided as a surface that is curved, preferably upwards. The sliding surface  383  of the first arm portion  310  may be provided as a surface that is curved in the opposite direction of the sliding surface  381 , preferably downwards. The sliding surface  381  and/or, as shown in  FIG. 4 h   , the sliding surface  383  may comprise a portion that extends essentially in parallel with a segment of the second arm portion  320  and/or a segment of the first  310  arm portion, respectively. The opening  312  may be provided at an edge of the first arm portion  310  as illustrated. The opening  312  may be sidewardly open along the width direction W. 
     Other features and functionalities of the embodiments in  FIGS. 1 c  and 4 g - h    may be similar to the embodiments described elsewhere in the present disclosure, such as in  FIGS. 1 a - b , 2 a - e , 3 a - f , 4 a - f , 7 a - d , 8 a   - f ,  9   a - f ,  10   a - f ,  11   a - f  and  12   a - b , whereby reference is made thereto. 
       FIG. 5 a    illustrates in an embodiment how to remove a floor element  200  from a flooring system comprising three floor elements  100 ,  200 ,  200 ′ and two connecting devices  300 ,  300 ′. The floor element  200 ′ is adjacent to an opposite edge portion  214  of the second floor element  200 . The connecting device  300  connecting the first  100  and second  200  floor elements is caused to transition from the first S 1  to the second S 2  horizontal state, e.g. by any method described in this disclosure, e.g. in relation to  FIGS. 2 a - b  and 2 e   , such as by horizontally displacing the floor elements  100 ,  200  relatively towards each other. In the present embodiment, the connecting devices  300 ,  300 ′ each comprise a locking device  380 , but this is in no way essential. 
     In the second horizontal state S 2 , a strength of the vertical connection of the floor elements  100 ,  200  may be reduced compared to a corresponding vertical strength in the first horizontal state S 1 . For example, the cooperation, such as a contact area, between the second engagement portion  222  and the second connecting portion  342 , may be reduced. This may be the case when the second side portion  370  comprises or forms the displaceable portion  316 . Alternatively, or additionally, the cooperation, such as a contact area, between the first engagement portion  122  and the first connecting portion  332 , may be reduced. This may be the case when the first side portion  360  comprises or forms the displaceable portion  316 . In fact, the floor elements  100 ,  200  may be vertically disconnected as shown in  FIG. 5 b   , e.g. in the case the second engagement portion  222  and the second connecting portion  342  disengage, or for example completely disengage, with each other. The second floor element  200  may have to be horizontally displaced away from the first floor element  100  for causing the disengagement. In some embodiments (not shown), the floor elements  100 ,  200  may be vertically disconnected in a case in which the first engagement portion  122  and the first connecting portion  332  disengage, or for example completely disengage, with each other. The first floor element  100  may have to be horizontally displaced away from the second floor element  200  for causing the disengagement. 
     Moreover, in the second horizontal state S 2  of the connecting device  300 , a strength of the vertical connection of the floor elements  200 ,  200 ′ may be reduced. For example, the cooperation between the first engagement portion  122  of the second floor element  200  and the first connecting portion  332  of the connecting device  300 ′ may be reduced. The floor elements  200 ,  200 ′ may be vertically disconnected as shown in  FIG. 5 a   , e.g. in a case in which the first engagement portion  122  and the first connecting portion  332  of the connecting device  300 ′ disengage, or for example completely disengage, with each other. Alternatively, or additionally, the cooperation between the second engagement portion  222  of the floor element  200 ′ and the second connecting portion  342  of the connecting device  300 ′ may be reduced. 
     Optionally, or additionally, in the second horizontal state S 2 , a strength of the vertical connection of the first floor element  100  and a floor element  100 ′ adjacent to an opposite edge portion  114  of the first floor element may be reduced in analogy with the vertical connection of the floor elements  200 ,  200 ′ whereby reference is made to the above. This is schematically illustrated in  FIG. 5 e   , whereby the connecting device  300  is put in the second horizontal state S 2  and the first floor element  100  is displaced towards the second floor element  200  for reducing the vertical connection of the floor elements  100 ,  100 ′.  FIG. 5 d    shows an embodiment of installed floor elements  100 ,  100 ′,  200 ,  200 ′ with connecting devices  300 ,  300 ′,  300 ″ schematically illustrated in first horizontal states S 1 . 
     In the second horizontal state S 2 , the floor element  200  provided between the floor elements  100 ,  200 ′, such as its opposite edge portion  214 , may be displaced vertically upwards V 1  and/or angled upwards A 1 , and thereby may be removed, see  FIG. 5 a   . In this configuration, the connecting device  300  may optionally be removed or replaced, e.g. by removing the fastening element  400  from the support member  500  (not shown). 
     In some embodiments, the edge portion  210  may be displaced vertically upwards and/or angled upwards. This may be suitable when the floor elements  100 ,  200  are configured as shown in  FIG. 5 b   , i.e. when the cooperation between portions  222  and  342  are reduced or completely disengaged as described above. It is understood that in some embodiments, both edge portions  210 ,  214  may be displaced. 
     In a non-limiting example, the floor elements  100 ,  200  and the connecting devices  300 ,  300 ′ may be configured such that the first  100  and/or the second  200  floor element is removable when the first and second floor elements, such as their upper parts, make contact. 
       FIGS. 5 a - c    also illustrate in an embodiment how to install a floor element  200  in a flooring system between two floor elements  100 ,  200 ′ using two connecting devices  300 ′ and  300  assuming the first S 1  and the second S 2  horizontal state, respectively. The floor element  200  is provided between the floor elements  100 ,  200 ′, preferably while providing the prominence  242  of the floor element  200  under the second lip  140  of the floor element  100  and/or while letting the second engagement portion  222  of the floor element  200  engage with the second connecting portion  342  of the connecting device  300 . The floor element  200 , preferably the opposite edge portion  214  thereof, is displaced vertically downwards and/or angled downwards, as indicated by the arrows V 2  and A 2 , respectively, in  FIG. 5 a   . When the underside  202  of the floor element  200  is provided on, or is aligned with, the support member  500  (not shown), the floor element  200  may be displaced horizontally towards the floor element  200 ′ so that the first engagement portion  122  of the floor element  200  cooperates with the first connecting portion  332  of the connecting device  300 ′, as shown in  FIG. 5   b.    
     Next, for connecting the floor elements  100 ,  200 , the connecting device  300  may need to transition from the second horizontal state S 2  back to the first horizontal state S 1 . In this embodiment, the locking device  380  thereby needs to be unlocked as described above in relation of  FIG. 3   d.    
     In a first example, and as shown in  FIG. 5 b   , an elongated, preferably flexible, element  620 , such as a string or a cord, may be inserted between the displaceable portion  316  and the contact portion  391  or between the first  360  and second  370  side portions or between the wall element  390  and the second side portion  370  in case the connecting device comprises a wall element as in e.g.  FIGS. 3 c - f   . The elongated element is preferably inserted in this manner before the floor element  200  is provided on the subfloor, but it is equally conceivable to insert it afterwards. The elongated element  620  may then unlock the locking device  380 , e.g. by pulling it upwards. For example, the first arm portion  310  may be displaced away from the second arm portion  320 . The method using the elongated element  620  can be particularly advantageous when the floor elements  100 ,  200  are configured to conceal the connecting device  300  when the floor elements are connected. Indeed, in this case the connecting device may be difficult to operate using a tool  610  from a position above the floor elements. However, it is clear that the method also is conceivable when the connecting device is visible from above and/or is accessible. 
     It is understood that the connecting devices  300 ,  300 ′ may be connected to the support member  500  during the removal and/or installation described above. 
     The embodiment in  FIGS. 6 a - b    illustrates another method for transitioning back to the first horizontal state S 1  which may be utilized when the connecting device is visible from above and/or is operable, preferably with a tool  610 , when the floor elements are connected, for example when there is a space  10  between upper parts of the edge portions  110 ,  210 . Indeed, the vertical displacement V 0  and/or the angling A 0  shown in the embodiment in  FIG. 3 d    for unlocking the locking device  380  may be attained by pushing the first arm portion  310  upwards using the tool  610 , such as a screw driver or a rod. This is illustrated in the side view in  FIG. 6 a    and in  FIG. 6 b    which is a front view as seen from the view C in  FIG. 6 a   . Alternatively, the locking device  380  may be unlocked manually by a similar operation. 
     In some embodiments, and as illustrated in  FIGS. 7 a - c   , the connecting device  300  does not comprise a locking element  380 . In the embodiment in  FIGS. 7 a - c   , there are no first  382  and second  384  locking elements provided on the arm portions  320 ,  310 . The end portion of the first  310  and/or second  320  arm portions may comprise a respective sliding surface  381 ,  383 , which preferably is at least partly planar. Thereby, the second arm portion may be guided over the first arm portion when the connecting device is compressed. A wall element  390  may extend from the bottom portion  350  and may join the second arm portion  320 . 
     The embodiment in  FIGS. 7 a - c    can be particularly advantageous for use with straps, ratchet straps, clamps, or similarly, e.g. in accordance with the discussion elsewhere in this disclosure. Indeed, an external compression force may be needed for maintaining the connecting device  300  in a second horizontal state S 2 . When no external compression force is applied, the connecting device may be in, or may transition back to, the first horizontal state S 1 . 
     Other features and functionalities of the embodiments in  FIGS. 7 a - c    may be similar to the embodiments described elsewhere in the present disclosure, such as in  FIGS. 1 a - c , 2 a - e , 3 a - f , 4 a - h  and 5 a   - c.    
     In some embodiments, the opening  312  may be provided at an edge of the first  310  and second  320  arm portions. Moreover, the opening  312  at each edge may be sidewardly open along the width direction W. In embodiments in which the connecting device comprises a locking device  380 , as illustrated in  FIG. 7 d   , the opening  312  may intersect the first  382  and second  384  locking elements.  FIG. 7 d    also illustrates that the arm portions  310 ,  320  may extend substantially in parallel, for example parallel to the plane HP in the connected state. Moreover,  FIG. 7 d    illustrates that the sliding surfaces  381  and  383  may extend above, for example entirely above, the second  320  and first  310  arm portions, respectively. 
       FIGS. 8 a - f    illustrate an embodiment of a connecting device  300  in two perspective views, a zoomed-in perspective view, two side views, and a top view. The connecting device comprises a first side portion  360  extending vertically from the bottom portion  350  and a second side portion  370 . A first  330  and a second  340  protrusion comprising a first  332  and a second  342  connecting portion, respectively, join and/or extend outwards from the first and second side portion, respectively. 
     The second side portion  370  comprises a first arm portion  310  comprising two arms  311 , preferably extending at least partially towards the first side portion  360  and preferably being provided symmetrically around a centre line CL extending along the width direction W. As illustrated in  FIG. 8 e   , each arm may form an angle ϕ with respect to a normal of the first side portion. In examples, the angle may be 10°≤ϕ≤60°, preferably 15°≤ϕ≤45°. 
     In the present embodiment, the displaceable portion  316  comprises the first arm portion  310  and is horizontally displaceable with respect to a body portion  314  of the connecting device, preferably along the width direction W. Thereby, a relative distance between first  360  and the second  370  side portions may be varied, preferably decreased. A portion of the body portion is fixed with respect to the support member  500  when the connecting device is connected thereto, and may comprise a bottom portion  350  and, optionally, the first side portion  360 . 
     Preferably, the first and second protrusions, and hence the first  332  and second  342  connecting portions, are horizontally fixed, in particular immobile, with respect to each other, such as when the displaceable portion  316  is horizontally displaced. 
     The displaceable portion  316  may be spaced from the second protrusion  340 , such as in the depth direction D. The arms  311  may be connected to the body portion  314 , preferably via an intermediate portion  375 , e.g. provided in the second side portion  370  as shown in  FIG. 8 c   , which may extend upwardly. 
     The displaceable portion  316  may be displaceable towards and away from the first side portion  360  as indicated by the arrows F 1 , F 2 . 
     In a first example, the connecting device comprises a single material, such as a polymer-based material or a metal, preferably steel. In a second example, the displaceable portion comprises a first material, such as a metal, preferably steel, and a body portion of the connecting device comprises a second material, such as a polymer-based material, e.g. PA, PP, PE, PVC, PS, PU, PC, ABS or TPE. In the second example, the displaceable portion may be formed separately from the body portion and may be attached thereto by an attaching element  317 , e.g. by a snapping element or by a tongue and tongue slot configuration. 
     As shown in  FIGS. 8 d  and 8 f   , the connecting device  300  may transition from the first S 1  to the second S 2  horizontal state by compressing the connecting device, preferably along the width direction W. The compression may be accomplished by displacing the displaceable portion  316  towards the first side portion  360 , see the arrow H 0  in  FIG. 8 d   . Embodiments of the horizontal extensions L 1 ′, L 1 ″ and L 2 ′, L 2 ″ have been described elsewhere in the disclosure, whereby reference is made thereto. 
     The connecting device comprises a first  362  and a second  372  abutment portion extending at least in a vertical direction V. The second abutment portion may comprise at least one curved abutment surface, such as two curved abutment surfaces  373 ,  373 ′. Each abutment surface is preferably curved around a vertical axis VA which extends along the vertical direction V. 
     The connecting device may comprise a barrier member  303  which is configured to prevent the displaceable portion  316 , such as the arm portion  310 , from being displaced beyond an obstruction element  304 , which in the present embodiment may be provided as a segment, or segments, of a first wall portion  313  of the first side portion  360 , which preferably is an inner portion thereof. The obstruction element  304  may be a contact portion  391 . Moreover, the barrier member may comprise a first barrier element  305  provided in the displaceable portion, such as the arm portion  310 , preferably in an end portion thereof, and a second barrier element  306  provided in a first wall portion  313  of the first side portion  360 . The first barrier element may be provided on each arm  311  and a corresponding second barrier element may be provided in the first wall portion. The first and second barrier elements are configured to cooperate with each other, preferably by engagement. 
     The end portion of the first arm portion  310  may be straight as shown in  FIGS. 8 a - f   . It is understood, however, and as shown in e.g.  FIGS. 9 a - b   , that in some embodiments the end portion may be curved, such as around the vertical axis VA, preferably outwards. 
     In the embodiment in  FIGS. 8 a - f   , and as further illustrated in a top view in an embodiment in  FIG. 9 a   , the second barrier element  306  may comprise a pocket  307  configured to receive at least a portion of the first barrier element  305 . The pocket may be curved around the vertical axis VA. 
     In some embodiments, however, and as illustrated in a top view in  FIG. 9 b   , the second barrier element  306  may be provided as a segment or segments in the first wall portion  313 . Each segment may be a planar surface. 
     A vertical extension of the end portion of the displaceable portion  316  may be smaller or substantially the same as a vertical extension of the second barrier element  306 . In some examples, and as shown in e.g.  FIGS. 8 b  and 8 d   , the end portion of the first arm portion  310  may have a smaller vertical extension than an inner portion of the first arm portion. 
     In some embodiments, and as shown in  FIG. 9 a   , but is also conceivable for the embodiment in  FIG. 9 b   , there may be a gap  11 ′ between the first wall portion  313  and the displacement portion  316  in the first horizontal state S 1 . In some embodiments, and as shown in  FIG. 9 b   , but is also conceivable for the embodiment in  FIG. 9 a   , there may be contact between said first wall portion and the displaceable portion in the first horizontal state S 1 . 
     In any of the embodiments in  FIGS. 8 a - f  and 9 a - b   , the end portion of the displaceable portion  316  may slide against the first wall portion  313  when the connecting device is compressed. For example, each arm  311  may slide outwards. Each arm  311  may slide out from the corresponding pocket  307  when a compression force exceeding a first threshold value is applied and may thereby slide against the first wall portion  313  provided outside of the pocket along the depth direction D, which may be planar. In some embodiments, when a compression force exceeding a second threshold value is applied, each arm  311  may be displaced beyond the first wall portion  313  along the depth direction D so that the arms  311 , such as end portions thereof, may be positioned in a region  308  beyond the obstruction element  304 . 
     Alternatively or additionally to the embodiments described above, the displaceable portion  316  may comprise the first side portion  360  which may be horizontally displaceable with respect to the body portion  314 , preferably along the width direction W. In these embodiments, the body portion may comprise the bottom portion  350  and, optionally, a portion of the second side portion  370 , such as the intermediate portion  375 . 
     In some embodiments, the connecting device may comprise at least two first protrusions  330  and/or at least two second  340  protrusions. As shown in a perspective view in the embodiment in  FIG. 10 f   , at least two second protrusions  340  may be provided on the displaceable portion  316 , such as the first arm portion  310 , e.g. in a top portion of the arms  311 . Each protrusion  330 ,  340  may be spaced from each other along the depth direction D and may extend in a direction away from a centre portion CP of the connecting device along the width direction W. Other features and functionalities of the protrusions  330 ,  340  may be similar to those described in other embodiments in this disclosure, whereby reference is made thereto. For example, the protrusions  330 ,  340  may join and/or extend outwards from the first  360  and the second  370  side portions, respectively. 
       FIG. 9 c    illustrates a side view of a flooring system comprising a first  100  and a second  200  floor element and a connecting system comprising the connecting device  300  in accordance with any of  FIGS. 8 a - f    or  9   a - b . Features of the embodiments of the floor elements in  FIGS. 9 c    and/or the connecting device may be similar to any of the embodiments described elsewhere in the present disclosure, such as in  FIGS. 1 a - c , 2 a - e , 5 a - c , 6 a - b , 7 c , 10 d  and 12 a   - b , whereby reference is made thereto. In particular, and as discussed in relation to  FIGS. 7 a - c   , an external compression force may be needed for maintaining the connecting device in a second horizontal state S 2 . 
       FIGS. 10 a - c    show in a perspective view, a side view, and a front view an embodiment of a connecting device  300  which is removably connectable to a support member  500 , such as a joist. The connecting device comprises a coupling portion  354  configured to cooperate with a mounting portion  510  of the support member, preferably by a snapping engagement. The mounting portion may be more rigid than the coupling portion.  FIG. 10 d    is a side view of a flooring system in which a first  100  and a second  200  floor element is connected to each other by a connecting device  300  in accordance with the embodiment in  FIGS. 10 a   - c.    
     In  FIGS. 10 a - d    the coupling portion  354  comprises at least one, such as a two, coupling elements  356  extending inwardly towards each other. Moreover, the mounting portion comprises a wing portion  512 . The wing portion may be provided on a vertically extending flank portion and may extend at least outwards from the flank portion. Thereby, the coupling portion  354  may be provided on an outside of the mounting portion  510  when connected thereto. In some embodiments, and as illustrated in  FIG. 10 e   , the coupling portion  354  may comprise at least one, such as two, coupling elements  356  extending outwardly away from each other. Moreover, the wing portion  512  may extend at least inwards from the flank portion. Thereby, the coupling portion  354  may be provided on an inside of the mounting portion  510  when connected thereto. 
     Other features and functionalities of the embodiments in  FIGS. 10 a - e    may be similar to the embodiments described elsewhere in the present disclosure, such as e.g. in  FIGS. 8 a - f , 9 a - c  and 10 f   , whereby reference is made thereto. Moreover, a coupling portion  354  configured to cooperate with a mounting portion  510  according to any embodiment above may replace the bottom portion  350  with the hole  352  in any of the embodiments of the present disclosure, such as those in  FIGS. 2 c - d , 3 a - f , 4 a - h , 7 a - b , 7 d  and 8 a   - f.    
       FIGS. 11 a - c    illustrate an embodiment of a connecting device  300  in a perspective view, a top view, and a bottom view.  FIG. 11 d    illustrates in a bottom view an embodiment of a connecting device wherein the first arm portion is separately formed from a body portion of the connecting device. Other features and functionalities may be similar to those in  FIGS. 11 a - c  and 11 e - f   .  FIGS. 11 e - f    illustrate an embodiment of a connecting device  300  in a perspective view and in a top view. The connecting device comprises a first arm portion that is integrally formed with a body portion of the connecting device. Other features and functionalities may be similar to those in  FIGS. 11 a - d   .  FIGS. 12 a - b    illustrate in a side view and a perspective view embodiments of floor elements  100 ,  200  connected by the connecting device  300  in any of  FIGS. 11 a   - f.    
     The connecting device comprises a first  360  and a second  370  side portion. A first  330  and a second  340  protrusion comprising a first  332  and a second  342  connecting portion, respectively, join and/or extend outwards from the first and second side portion, respectively. 
     As illustrated in  FIGS. 11 a - f   , the first protrusion  330  and/or the second  340  protrusion may comprise a bevel  309 ,  319 . Optionally, a lower wall  133 ,  233  of the first lip  130  and/or the first lip  230  may comprise an inclined surface  131 ,  231  (see, e.g.,  FIG. 1 b   ). An angle of the bevel  309  may correspond to an angle of the inclined surface  231 . Moreover, an angle of the bevel  319  may correspond to an angle of the inclined surface  131 . 
     In some embodiments, and as described above e.g. in relation to  FIG. 10 f   , the connecting device may comprise at least two first protrusions  330  and/or at least two second  340  protrusions. Reference is made to the above for details. 
     The connecting device comprises an arm portion  310  which may be a first arm portion. The displaceable portion  316  comprises the first arm portion which is horizontally displaceable with respect to a body portion  314  of the connecting device, preferably along the width direction W. Thereby, a relative distance between the first arm portion  310  and the second side portion  370  may be varied, preferably decreased. 
     The first  330  and second  340  protrusions may be provided in a top portion  318  of the connecting device. Preferably, the first and second protrusions, and hence the first  332  and second  342  connecting portions, are horizontally fixed, in particular immobile, with respect to each other, such as when the displaceable portion is horizontally displaced. 
     The first arm portion may be provided in the first side portion  360 . Alternatively, however, in some embodiments (not shown) an arm portion, such as a second arm portion, may be provided in the second side portion  370 . Thereby, the second arm portion of the second side portion may form a displaceable portion. In some embodiments (not shown), a first and a second arm portion may be provided in the first and the second side portions, respectively. Thereby, the first and second arm portions may form a displaceable portion. 
     The connecting device may comprise an interstitial portion  351  as shown in  FIGS. 11 a - c   . The interstitial portion is preferably limited by a first  313  and a second  315  wall portion which may be provided in the first and second side portions, respectively. Preferably, the first and second wall portions are provided below the first  330  and second  340  protrusions, respectively. Moreover, the first and second wall portions are preferably provided inwardly of an outermost surface of the first  330  and second  340  protrusions, respectively. 
     In the embodiments in  FIGS. 11 a - f   , the first arm portion  310  comprises one arm  311 , which preferably is curved. The arm may comprise a first portion preferably extending at least partially in a direction away from the first wall portion  313 , which preferably comprises a contact portion  391  and/or an obstruction element  304 . In embodiments where the first arm portion is separately formed from the first wall portion, the first portion may be attached to the first wall portion by an attaching element  317  such as a snapping element as shown in  FIG. 11 b    or a tongue and tongue slot configuration. 
     The arm may further comprise a second portion preferably extending at least partially in a direction towards the first wall portion  313 . The first portion may form an angle, such as a maximal angle, α with respect to an axis extending along the depth direction D. The second portion may form an angle, such as a maximal angle, β with respect to said axis. The angle of the second portion may be larger than the angle of the first portion. In examples, the angles may be 5°≤α≤40°, preferably 15°≤α30°, and 10°≤β≤50°, preferably 20°≤β≤40°. 
     The body portion  314  may comprise portions that are horizontally fixed, in particular immobile, when the displaceable portion is horizontally displaced. The body portion may comprise the bottom portion  350  and/or the interstitial portion  351 , such as the first wall portion  313 . The body portion may comprise the first and the second side portions. 
     At least portions of the displaceable portion  316  may be displaceable towards and away from the first wall portion  313 . 
     The connecting device comprises a first  362  and a second  372  abutment portion extending at least in a vertical direction V. The first abutment portion may be provided on the displaceable portion  316  and may comprise at least one curved abutment surface  373 . Each abutment surface is preferably curved around a vertical axis VA which extends along the vertical direction V. 
     In embodiments (not shown) where an arm portion of the second side portion also forms a displaceable portion as explained above, the second abutment portion may be provided on the displaceable portion and may comprise at least one curved abutment surface. 
     An extension of the first protrusion  330 , in particular the connecting portion  332 , along the width direction W from the first wall portion  313  preferably is larger than an extension of the second protrusion  340 , in particular the second connecting portion  342 , from the second wall portion  315 . Thereby, the first arm portion may be accommodated under the first protrusion while allowing for engagement between the first connecting portion and the first engagement portion  122 . Moreover, a floor element may be displaced by a smaller distance towards the connecting device for compressing the first arm portion and allowing for a removal of the floor element, such as by angling. 
     The connecting device may comprise a barrier member  303  which is configured to prevent the displaceable portion, such as the arm portion  310 , from being displaced beyond the obstruction element  304 , which in the present embodiment may be provided as a segment, or segments, of the first wall portion  313 . Moreover, the barrier member may comprise a first barrier element  305  provided in the displaceable portion, such as the arm portion  310 , preferably in an end portion thereof, and a second barrier element  306  provided in the first wall portion  313 . The first and second barrier elements are configured to cooperate with each other, preferably by engagement. 
     Embodiments of the barrier member may be the same as those described above in relation to e.g.  FIGS. 8 b  and 9 a - b   , whereby reference is made thereto. 
     The end portion of the first arm portion  310  may be straight as shown in  FIGS. 8 a - f , 11 a - c  and 11 e - f   . It is understood, however, that in some embodiments the end portion may be curved as in  FIG. 11   d.    
     As shown in  FIG. 11 d   , the second barrier element  306  may comprise a pocket  307  configured to receive at least a portion of the first barrier element  305 . Embodiments of the pocket are analogous to the embodiments described in relation to  FIGS. 8 a - f  and 9 a   , whereby reference is made to the above. 
     In some embodiments, however, and as illustrated in  FIGS. 11 a  and 11 c   , the second barrier element  306  may be provided as a segment or segments in the first wall portion  313 . The segment may be a planar surface. 
     As described in relation to  FIGS. 8 a - f  and 9 a - b   , in any of the embodiments in  FIGS. 11 a - f    the end portion of the displaceable portion  316  may slide against the first wall portion  313  when the connecting device is compressed. For example, the arm  311  may slide out from the pocket  307  when a compression force exceeding a first threshold value is applied and, in some embodiments, when a compression force exceeding a second threshold value is applied, the arm  311  may be displaced beyond the first wall portion  313 . 
     As illustrated in  FIG. 11 c   , the connecting device  300  may transition from the first S 1  to the second S 2  horizontal state by compressing the connecting device, preferably along the width direction W. The compression may be accomplished by displacing the displaceable portion  316  towards the first wall portion  313 , see the arrow H 1 . A horizontal extension L 2 , L 2 ′, L 2 ″ of the connecting device in the second horizontal state S 2  is smaller than a horizontal extension L 1 , L 1 ′, L 1 ″ of the connecting device in the first horizontal state S 1 . 
     Removal and/or installation of a floor element may be similar to the procedure described in relation to  FIGS. 5 a - c   , whereby reference is made to the above. In particular, the connecting device may be horizontally compressed by horizontally displacing the floor elements relatively towards each other, such as by horizontally displacing the first floor element  100  relatively towards the second floor element  200 , see  FIGS. 12 a - b   . When the connecting device is provided in the second horizontal state S 2 , the floor element  100 , such as its edge portion  210 , may be displaced vertically upwards V 3  and/or angled upwards A 3 , and may thereby be removed. 
     In some embodiments, and as shown in  FIG. 11 c   , the horizontal extension in the first S 1  and second S 2  horizontal states is a horizontal extension L 1 ″, L 2 ″ between the displaceable portion  316 , such as the arm portion  310 , and a fixed surface of the connecting device, such as the second protrusion  340 . The horizontal extension may be a maximal horizontal extension, such as a distance between an outermost surface of the displaceable portion and an outermost surface of the second protrusion along the width direction W. In some embodiments, and as shown in  FIG. 11 f   , the horizontal extension L 1 , L 2  in the first S 1  and second S 2  horizontal states is a maximal horizontal extension of the connecting device, such as at a top portion  318  thereof. 
     The connecting device may be removably connectable to a support member  500 , such as a joist. The connecting device may comprise a coupling portion  354  configured to cooperate with a mounting portion  510  of the support member, preferably by a snapping engagement. For example, the coupling portion  354  and mounting portion  510  may be embodied as in any of  FIGS. 10 a   - e.    
     In some embodiments, and as shown in  FIGS. 11 a - f   , the coupling portion  354  may comprise a plurality of coupling elements  356 , such as two or four coupling elements, that preferably extend inwardly towards each other. Thereby, the coupling portion  354  may be provided on an outside of the mounting portion  510  when connected. With reference to the discussion above in relation to  FIG. 10 e   , it is clear that in some embodiments the coupling portion  354  may comprise a pair of coupling elements  356  extending outwardly away from each other. Thereby, the coupling portion  354  may be provided on an inside of the mounting portion  510  when connected. 
     A portion of the body portion  314  may be fixed to the support member  500  when the connecting device is connected thereto, and may comprise a bottom portion  350  and/or the interstitial portion  351 . 
     Alternatively, or additionally, and as indicated in  FIGS. 11 a - f   , a fastening element  400 , e.g. in the form of a screw, may be provided through a hole  352  in the connecting device and fastened to the support member. The hole may be provided in the interstitial portion  351 . In some embodiments, the connecting device comprises a hole  352  and does not comprise any coupling elements  356 . In such embodiments, a portion provided vertically below the interstitial portion  351  may optionally be removed. 
     Hence, a connecting device comprising a coupling portion  354  and a support member  500  comprising a mounting portion  510  may be replaced by a connecting device configured to be fastened to a support member by a fastening element  400  as described e.g. in any of  FIGS. 1 a - c , 2 a - e , 3 a - f , 4 a - h , 7 a - d , 8 a   - f ,  9   a - c  and  10   f.    
     In a first example, and as illustrated in  FIGS. 11 e - f   , the connecting device may be integrally formed and may comprise a single material, such as a polymer-based material. In a second example, and as illustrated in  FIGS. 11 a - d   , the displaceable portion may comprise a first material, such as a metal, preferably steel, and the body portion of the connecting device may comprise a second material, such as a polymer-based material, e.g. PA, PP, PE, PVC, PS, PU, PC, ABS, or TPE. 
     The connecting device, such as in any of the embodiments in  FIGS. 10 a - f , 11 a - f  and 12 a - b   , may be pretensioned against the support member. Thereby, a longitudinal displacement of the connecting device relative the support member may be counteracted. Embodiments of this are described in WO 2018/169483 e.g. on page 22, line 8 to page 24, line 23 and page 61, line 26 to page 62, line 14, which hereby is incorporated by reference. For example, the support element may comprise at least one retention element for holding at least one friction member. 
     Other features and functionalities of the embodiments in  FIGS. 10 a - f , 11 a - f  and 12 a - b    may be similar to those described in relation to the embodiments in  FIGS. 8 a - f  and 9 a - f   , whereby reference is made to those parts of the disclosure. 
     In non-limiting examples, a width and a depth of the connecting device in any of the embodiments of the present disclosure may be 2 cm≤W≤6 cm, 2 cm≤D≤6 cm and a vertical extension may be 0.5 cm≤V≤4 cm. 
       FIGS. 9 d - f    show in graphs a non-linear behavior of the connecting device in accordance with some embodiments thereof. An applied compression force F, such as either or both of those shown in  FIG. 4 a   , is plotted as a function of a displacement δ of the connecting device during its compression. The origin in these graphs may correspond to the connecting device being provided in the first horizontal state S 1 . The graphs are divided into linear regions L, in which the behavior is linear or substantially linear, and non-linear regions NL. 
     The graph in  FIG. 9 d    may correspond to the behavior of a connecting device in accordance with any of the embodiments in e.g.  FIGS. 2 c - d , 3 a - f , 4 a - d , 4 g - h , 7 a - b , 7 d   ,  8   a - f ,  9   a - b ,  10   a - f  and  11   a - f . A first linear region L near the origin may correspond to a configuration of the connecting device in which there is a gap  11 ,  11 ′ in the first horizontal state S 1  and during an initial compression of the connecting device. 
     A subsequent non-linear region NL may correspond to a configuration of the connecting device wherein the connecting device transitions from the first S 1  to the second S 2  horizontal state by being compressed and whereby the displaceable portion  316  makes contact with a contact portion  391  of the connecting device, such as the first arm portion  310  making contact with the second arm portion  320  or with the first wall portion  313 . In a first example, sliding surfaces  381 ,  383  may slide against each other e.g. as in any of the embodiments in  FIGS. 2 c - d , 3 a - f , 4 a - d , 4 g - h , 7 a - b  and 7 d   . In a second example, the end portion of the arm portion  310  and the first wall portion  313  may contact, such as slide against, each other e.g. as in any of the embodiments in  FIGS. 8 a - f , 9 a - b , 10 a - f  and 11 a   - f.    
     A subsequent linear region L may correspond to a behavior of the connecting device wherein the displaceable portion  316  and the contact portion  391  do not cooperate anymore during compression or when the displaceable portion has been displaced beyond the obstruction element  304 , such as when the first  382  and second  384  locking elements do not cooperate anymore during the compression or when the arm portion  310  has been displaced beyond the obstruction element  304 . In a first example, the sliding surface  383  may pass the sliding surface  381  along the width direction W as conceivable in any of the embodiments in e.g.  FIGS. 2 c - d , 3 a - f , 4 a - d , 4 g - h , 7 a - b  and 7 d   . In a second example, the arm portion  310 , such as each arm  311 , may be displaced beyond the first wall portion  311  along the depth direction D as conceivable in any of the embodiments in  FIGS. 8 a - f , 9 a - b , 10 a - f  and 11 a - f   . In a first example, the linear spring constants in the first linear region L and the subsequent linear region L are essentially the same. Thereby, an applied compression force may be increased substantially constantly for compressing the connecting device, except in the non-linear region NL. In a second example, the linear spring constants in the first linear region L and the subsequent linear region L are different. By having a larger spring constant in the first linear region L than in the subsequent linear region L a risk of an accidental disconnection of the connecting device may be reduced, while facilitating disconnection once such disconnection has been commenced. 
     The graph in  FIG. 9 e    may correspond to the behavior of a connecting device in accordance with any of the embodiments in e.g.  FIGS. 2 c - d , 3 a - f , 4 a - h , 7 a - b , 7 d , 8 a - f   ,  9   a - b ,  10   a - f  and  11   a - f . A non-linear region NL near the origin may correspond to a configuration of the connecting device in which there is contact between the displaceable portion  316  and the contact portion  391  of the connecting device. Hence, the non-linear region NL and the subsequent linear region L in  FIG. 9 e    may correspond to the non-linear region NL and the subsequent linear region L, respectively, as described in relation to  FIG. 9 d    whereby reference is made to the above. 
     The graph in  FIG. 9 f    may correspond to the behavior of a connecting device in accordance with any of the embodiments in e.g.  FIGS. 2 c - d , 3 a - f , 4 a - h , 7 a - b , 7 d , 8 a - f   ,  9   a - b ,  10   a - f  and  11   a - f . A non-linear region NL may correspond to a configuration of the connecting device in which there is contact between the displaceable portion  316  and the contact portion  391  as described above, such as between the first arm portion  310  and the second arm portion  320  or the first side portion  360 , such as the first wall portion, in the first horizontal state S 1  as well as during the compression of the connecting device. 
     F TH  indicates a predetermined threshold value of the compression force needed for transitioning from the first to the second horizontal state and is preferably located in a non-linear region NL. 
     Thus, the connecting device may be provided with a non-linear spring constant along a horizontal direction or, equivalently, a horizontal spring constant. The non-linear spring constant k(δ) may be dependent on a degree of compression of the connecting device along the width direction W. 
     Hence, the connecting device may be provided with at least a first k 1  and a second k 2  horizontal spring constant, optionally also a third horizontal spring constant k 3 . Each horizontal spring constant may be consecutively activated, preferably at different horizontal relative positions of the displaceable portion  316  and the contact portion  391 , for example at different horizontal relative positions between the first  310  and second  320  arm portions, such as the locking elements  382 ,  384 , or between the first arm portion  310  and the first wall portion  313 . In non-limiting examples, any of the horizontal spring constants k 1 , k 2  and k 3  may be a substantially linear or a non-linear horizontal spring constant. In  FIG. 9 d   , k 1  and k 3  are substantially linear and k 2  is non-linear. In  FIG. 9 e   , k 1  is non-linear and k 2  is substantially linear. In  FIG. 9 f   , k 1  is non-linear. 
     The inventive concept has mainly been described above with reference to a few exemplary embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims and the items in an “Exemplary Embodiments” section below. For instance, the edge portions of the floor elements may be configured differently; for example, the embodiments of the second lips  140 ,  240  may be interchanged between the first  100  and second  200  floor elements. Moreover, the contact portion  391  and the displaceable portion  316  may be connected to each other by a breaking portion  386  in any of the embodiments of the disclosure, such as those in  FIGS. 7 a - d , 8 a - f , 9 a - c , 10 a - f  and 11 a - f   . Embodiments of the removal and installation of a floor element described in  FIGS. 5 a - c    may work similarly for other connecting devices disclosed in this disclosure, such as those without a locking element  380 . Finally, it is emphasized that any of the embodiments of the first and second aspects in the summary and of the aspects provided in the “Exemplary Embodiments” section below may be combined with any of the embodiments described in relation to  FIGS. 1 a - c , 2 a - e , 3 a - f , 4 a - h , 5 a - e , 6 a   - b ,  7   a - d ,  8   a - f ,  9   a - f ,  10   a - e ,  11   a - f  and  12   a - b  of the present disclosure. 
     EXEMPLARY EMBODIMENTS 
     Further exemplary aspects of the inventive concept are provided below. Exemplary embodiments of these aspects are largely analogous to the exemplary embodiments as described above, whereby reference is made to the above for a detailed description. 
     Item 1. A flooring system, such as a decking system, comprising floor elements and a connecting system comprising a connecting device ( 300 ) for connecting a first floor element ( 100 ) and a second floor element ( 200 ),
         wherein the connecting device comprises a first ( 332 ) and a second ( 342 ) connecting portion,   wherein an edge portion ( 110 ;  210 ) of the first and second floor elements comprises a first ( 122 ) and a second ( 222 ) engagement portion, respectively,   the first and the second connecting portions being configured to cooperate with the first and the second engagement portions, respectively, for vertically connecting the first and second floor elements, and   wherein the connecting device further comprises a displaceable portion ( 316 ) which is horizontally displaceable, preferably along a width direction (W) of the connecting device.       

     Item 2. The flooring system according to item 1, wherein the displaceable portion ( 316 ) is horizontally displaceable with respect to a body portion ( 314 ) of the connecting device. 
     Item 3. The flooring system according to item 1 or 2, wherein a first ( 360 ) and/or a second ( 370 ) side portion of the connecting device forms the displaceable portion ( 316 ), for varying, preferably decreasing, a relative distance between the first and second side portions. 
     Item 4. The connecting device according to item 2 or 3, wherein a portion of the body portion is configured to be fixed with respect to a support member ( 500 ) when the connecting device is connected, preferably removably connected, thereto, and wherein the body portion comprises a bottom portion ( 350 ) and, optionally, a first ( 360 ) and/or a second ( 370 ) side portion of the connecting device. 
     Item 5. The flooring system according to any of the preceding items 1-4, wherein the connecting device is configured to assume a first (S 1 ) and a second (S 2 ) horizontal state, a horizontal extension (L 2 ; L 2 ′; L 2 ″) of the connecting device in said second horizontal state being smaller than a horizontal extension (L 1 ; L 1 ′; L 1 ″) of the connecting device in said first horizontal state. 
     Item 6. The flooring system according to item 5, wherein the connecting device is configured to transition from the first horizontal state to the second horizontal state by horizontally compressing the connecting device and displacing the displaceable portion. 
     Item 7. The flooring system according to item 6, wherein the connecting device is configured to be horizontally compressed by horizontally displacing the first and second floor elements relatively towards each other. 
     Item 8. The flooring system according to any of the preceding items, wherein said first and second connecting portions joins and/or extends outwards from a first ( 360 ) and a second ( 370 ) side portion of the connecting device, respectively. 
     Item 9. The flooring system according to any of the preceding items, wherein the first ( 332 ) and second ( 342 ) connecting portions are horizontally fixed, in particular immobile, with respect to each other when the displaceable portion is horizontally displaced. 
     Item 10. The flooring system according to any of the preceding items 1-8, wherein the first ( 332 ) and second ( 342 ) connecting portions are displaced horizontally with respect to each other when the displaceable portion is horizontally displaced. 
     Item 11. The flooring system according to any of the preceding items 5-10, wherein the horizontal extension of the connecting device in each of said first and second horizontal states is:
         a maximal horizontal extension (L 1 ; L 2 ) of the connecting device, such as at a top portion ( 318 ) thereof, or   a horizontal extension (L 1 ′; L 2 ′), such as a maximal horizontal extension, between a first abutment portion ( 362 ) and a second abutment portion ( 372 ) configured to abut the first and second floor elements, respectively, in the first horizontal state, said first and second abutment portions extending at least in a vertical direction (V), or   a horizontal extension (L 1 ″; L 2 ″) between the displaceable portion ( 316 ), such as an outermost surface thereof along a width direction (W), and a fixed surface of the connecting device, such as a first ( 330 ) or a second ( 340 ) protrusion, such as an outermost surface thereof along a width direction (W).       

     Item 12. The flooring system according to any of the preceding items 5-11, wherein a ratio (R) between the horizontal extension (L 2 ; L 2 ′; L 2 ″) of the connecting device in said second horizontal state and the horizontal extension (L 1 ; L 1 ′; L 1 ″) of the connecting device in said first horizontal state is less than or equal to 0.95, preferably less than or equal to 0.9, and more preferably less than or equal to 0.85. 
     Item 13. The flooring system according to any of the preceding items, wherein the first and second floor elements are vertically connected in said first horizontal state, and wherein in said second horizontal state:
         a strength of a vertical connection of a pair of floor elements in the flooring system is reduced compared to a strength of the vertical connection of said pair of floor elements in the first horizontal state, such as the pair of floor elements being vertically disconnected, and/or   at least one floor element in said pair of floor elements is removable in said second horizontal state, such as by angling and/or by a vertical displacement of the respective floor element.       

     Item 14. The flooring system according to any of the preceding items, wherein the connecting device further comprises a locking device ( 380 ) for locking the connecting device in said second horizontal state. 
     Item 15. The flooring system according item 14, wherein the locking device comprises a first ( 382 ) and a second ( 384 ) locking element configured to cooperate with each other, such as by a snapping engagement. 
     Item 16. The flooring system according to item 15, wherein the first and the second locking elements are provided on a first ( 310 ) and a second ( 320 ) arm portion of the connecting device, respectively, said first and second arm portions preferably extending horizontally towards each other. 
     Item 17. The flooring system according to any of the preceding items, wherein the displaceable portion is connected to a contact portion ( 391 ) of the connecting device by a breaking portion ( 386 ), such as a first ( 382 ) and a second ( 384 ) locking element being connected to each other by a breaking portion ( 386 ). 
     Item 18. The flooring system according to any of the preceding items 14-17, wherein the first and the second locking elements are provided with a resistance element ( 387 ). 
     Item 19. The flooring system according to any of the preceding items 14-18, when depending on any of the items 5-13, wherein the locking device is configured to be unlocked from said second horizontal state by compressing, preferably horizontally compressing, the connecting device and/or by displacing a first arm portion ( 310 ) of the connecting device away from a second arm portion ( 320 ) of the connecting device, such as by a vertical displacement and/or an angling thereof. 
     Item 20. The flooring system according to any of the preceding items, wherein the connecting device comprises a guiding surface ( 385 ), optionally joining a second locking element ( 384 ) of a locking device ( 380 ) of the connecting device for locking the connecting device in a second horizontal state (S 2 ). 
     Item 21. The flooring system according to any of the preceding items, wherein the displaceable portion comprises an arm portion ( 310 ), such as a first arm portion. 
     Item 22. The flooring system according to item 21, wherein the arm portion ( 310 ) is a first arm portion ( 310 ) and wherein the connecting device further comprises a second arm portion ( 320 ), the first and the second arm portions preferably extending horizontally towards each other. 
     Item 23. The flooring system according to item 21 or 22, wherein the arm portion ( 310 ) is provided in a first ( 360 ) or a second ( 370 ) side portion, preferably comprising a first portion extending at least partially in a direction away from a wall portion ( 313 ;  315 ) of the first ( 360 ) or second ( 370 ) side portion and optionally further comprising a second portion extending at least partially in a direction towards the wall portion. 
     Item 24. The flooring system according to any of items 21-23, wherein the arm portion ( 310 ) comprises at least two arms ( 311 ), preferably extending at least partially towards a first side portion ( 360 ) and preferably being provided symmetrically around a centre line (CL) extending along a width direction (W). 
     Item 25. The flooring system according to any of the preceding items, wherein the connecting device comprises a barrier member ( 303 ) configured to prevent the displaceable portion, such as an arm portion ( 310 ), from being displaced beyond an obstruction element ( 304 ). 
     Item 26. The flooring system according to item 25, wherein the barrier member comprises a first barrier element ( 305 ) and a second barrier element ( 306 ) configured to cooperate with the first barrier element, said first barrier element preferably being provided in the displaceable portion and said second barrier element preferably being provided in a first side portion ( 360 ) of the connecting device, such as in a wall portion ( 313 ) thereof. 
     Item 27. The flooring system according to item 26, wherein the second barrier element comprises a pocket ( 307 ) configured to receive at least a portion of the first barrier element. 
     Item 28. The flooring system according to any of the preceding items, wherein the first and second connecting portions are provided on a first ( 330 ) and a second ( 340 ) protrusion of the connecting device, respectively. 
     Item 29. The flooring system according to item 28, wherein the connecting device comprises a top portion ( 318 ) comprising said first ( 330 ) and second ( 340 ) protrusions. 
     Item 30. The flooring system according to any of the items 5-29, wherein the connecting device comprises a first abutment portion ( 362 ) and/or a second abutment portion ( 372 ) configured to abut the first and/or second floor elements in the first horizontal state (S 1 ), said first and second abutment portions extending at least in a vertical direction (V). 
     Item 31. The flooring system according to item 30, wherein the first ( 362 ) and/or the second ( 372 ) abutment portion comprises at least one curved abutment surface ( 373 ;  373 ′). 
     Item 32. The flooring system according to item 31 or 32, wherein the first ( 362 ) or the second ( 372 ) abutment portion is provided on an arm portion, such as a first arm portion ( 310 ). 
     Item 33. The flooring system according to any of the preceding items, wherein a first section ( 301 ) of the connecting device is more flexible, preferably horizontally flexible, than a second section ( 302 ) of the connecting device, said first section preferably being provided adjacent to the second floor element and said second section preferably being provided adjacent to the first floor element when the first and second floor elements are connected. 
     Item 34. The flooring system according to any of the preceding items, wherein the first and second engagement portions are provided in a first groove ( 120 ) and a second groove ( 220 ), respectively, of the first and second floor elements. 
     Item 35. The flooring system according to item 34, wherein said edge portion ( 110 ;  210 ) of each of the first and second floor elements comprises a first ( 130 ;  230 ) and a second ( 140 ;  240 ) lip provided below and above the first ( 120 ) and the second ( 220 ) groove of the first and second floor elements, respectively. 
     Item 36. The flooring system according to item 35, wherein the second lip ( 140 ) of the first floor element extends horizontally beyond the first lip ( 130 ) of the first floor element, and/or wherein the second lip ( 240 ) of the second floor element extends horizontally beyond the first lip ( 230 ) of the second floor element. 
     Item 37. The flooring system according to item 35 or 36, wherein the second lip ( 240 ) of the second floor element comprises a prominence ( 242 ) extending beyond an uppermost portion ( 212 ) of the edge portion ( 210 ) of the second floor element. 
     Item 38. The flooring system according to item 37, wherein the second lip ( 140 ) of the first floor element and said prominence ( 242 ) at least partially overlap each other in a horizontal plane (HP) being parallel with a top side ( 101 ;  201 ) and/or an underside ( 102 ;  202 ) of each floor element. 
     Item 39. The flooring system according to any of the preceding items, wherein the first and second floor elements are configured to conceal the connecting device when the floor elements are connected, preferably such that edge portions ( 110 ;  210 ) of the first and second floor elements at least partially overlap each other in a horizontal plane (HP) being parallel with a top side ( 101 ;  201 ) and/or an underside ( 102 ;  202 ) of each floor element. 
     Item 40. The flooring system according to any of the preceding items 1-38, wherein the connecting device is visible when the first and second floor elements are connected. 
     Item 41. The flooring system according to any of the items 34-40, wherein the connecting device comprises a protruding element ( 322 ) configured to be provided in the first groove ( 120 ), the first groove ( 120 ) optionally comprising a recess ( 124 ) for accommodating at least a portion of said protruding element. 
     Item 42. The flooring system according to any of the preceding items, wherein the connecting device comprises a friction element ( 364 ), preferably provided in a cavity ( 366 ) of the connecting device, and being configured to engage with the first floor element ( 100 ) in the first horizontal state. 
     Item 43. The flooring system according to any of the items 5-42, wherein the connecting device is configured to transition from the first horizontal state (S 1 ) to the second horizontal state (S 2 ) when a compression force of the connecting device exceeds a predetermined threshold value F TH . 
     Item 44. The flooring system according to any of the preceding items, wherein the connecting device is provided with a non-linear spring constant along a horizontal direction, said horizontal direction preferably being parallel with a width direction (W) of the connecting device. 
     Item 45. The flooring system according to any of the preceding items, wherein a spring constant of the connecting device along a horizontal direction (W) is configured to decrease when compressing the connecting device from a first compression level to a second compression level. 
     Item 46. The flooring system according to any of the preceding items, wherein the connecting device is connectable, preferably removably connectable, to a support member ( 500 ), such as by a fastening element ( 400 ) provided through a hole ( 352 ) in the connecting device. 
     Item 47. The flooring system according to any of the preceding items, wherein the connecting device comprises a coupling portion ( 354 ) configured to cooperate with a mounting portion ( 510 ) of a support member ( 500 ), preferably by a snapping engagement. 
     Item 48. The flooring system according to any of the preceding items, wherein, in the first horizontal state (S 1 ), the first connecting portion ( 332 ) and/or the second connecting portion ( 342 ) extend(s) essentially in parallel with a top side ( 101 ;  201 ) and/or an underside ( 102 ;  202 ) of the floor elements, and, optionally, the first connecting portion ( 332 ) and/or the second connecting portion ( 342 ) include(s) a respective surface that is essentially parallel to the top side ( 101 ;  201 ) and/or the underside ( 102 ;  202 ) of the floor elements. 
     Item 49. The flooring system according to any of the preceding items, wherein the first engagement portion ( 122 ) and/or the second engagement portion ( 222 ) extend(s) essentially in parallel with the top side and/or the underside of the floor elements, the first and second engagement portions optionally being provided in the form of a first ( 123 ) and a second ( 223 ) lower wall of a first groove ( 120 ) and a second groove ( 220 ), respectively, of the first and second floor elements. 
     Item 50. The flooring system according to any of the preceding items, wherein a spring constant of the connecting device along a horizontal direction is configured to decrease when compressing the connecting device from a first compression level to a second compression level. 
     Item 51. The flooring system according to any of the preceding items, wherein the connecting device is integrally formed. 
     Item 52. The flooring system according to item 51, wherein the displaceable portion ( 316 ) is integrally formed with the connecting device, such as with a body portion ( 314 ) of the connecting device. 
     Item 53. A connecting device ( 300 ), independently or according to any of the preceding items 1-52, for connecting a first floor element ( 100 ) and a second floor element ( 200 ) comprising:
         a first ( 332 ) and a second ( 342 ) connecting portion being configured to cooperate with a first ( 122 ) and a second ( 222 ) engagement portion of said first and second floor elements, respectively, for vertically connecting the first and second floor elements, and   a displaceable portion ( 316 ) which is horizontally displaceable with respect to a body portion ( 314 ) of the connecting device, preferably along a width direction (W) of the connecting device.