Source: http://www.sumobrain.com/patents/wipo/Helmet/WO2019134973A1.html
Timestamp: 2019-08-17 11:38:05
Document Index: 662844614

Matched Legal Cases: ['art 51', 'art 52', 'art 51', 'art 52', 'art 51', 'art 52', 'art 52', 'art 51', 'art 52', 'art 77', 'arts 78', 'art 77', 'arts 77', 'arts 77', 'arts 77']

WIPO Patent Application WO/2019/134973
A helmet comprising: an inner shell (22); an outer shell (21); a sliding interface (23) between the inner shell and the outer shell; and a switch (20) configured to be selectively switchable between first and second discrete modes, the first mode allowing relative sliding between the inner shell and the outer shell at the sliding interface in response to an impact to the helmet, the second mode preventing relative sliding between the inner shell and the outer shell at the sliding interface.
HALLDIN, Peter (C/O MIPS AB, Källtorpsvägen 2, Täby, SE-183 71, SE)
LINDBLOM, Kim (C/O MIPS AB, Källtorpsvägen 2, Täby, SE-183 71, SE)
EP2019/050171
US20170112220A1 2017-04-27
a sliding interface between the inner shell and the outer shell; and
a switch configured to be selectively switchable between first and second discrete modes, the first mode allowing relative sliding between the inner shell and the outer shell at the sliding interface in response to an impact to the helmet, the second mode preventing relative sliding between the inner shell and the outer shell at the sliding interface.
2. A helmet according to claim 1, wherein the switch comprises a moveable lock; the first and second modes correspond to the first and second positions, respectively, of the moveable lock;
in the first position, the lock does not engage with least one of the inner shell and the outer shell; and
in the second position, respective parts of the lock engage with the inner shell and the outer shell to prevent relative sliding between the inner shell and the outer shell.
3. A helmet according to claim 2, wherein the movable lock is mounted to one of the inner shell and the outer shell; and, when the moveable lock is in the second position, a part of the movable lock is inserted in a recess in the other of the inner shell and outer shell.
4. A helmet according to claim 3, wherein an end of the moveable lock is rotably attached to one of the inner shell and the outer shell; and,
in moving from the first position and the second position, the moveable lock is rotated about said end of the moveable lock.
5. A helmet according to claim 3, wherein the moveable lock is slidably mounted to said one of the inner shell and outer shell to enable the lock to move from the first position to the second positon.
6. A helmet according to claim 5, wherein the moveable lock is configured such that, in sliding from a first position to the second position, a protrusion of the moveable lock may extend at an angle relative to a direction in which the movable lock slides; and,
in the second position, said protrusion is inserted in said recess.
7. A helmet according to claim 5, wherein the moveable lock comprises a protrusion arranged such that, when the moveable lock is in the first position, the protrusion is not aligned with the recess and the movable lock is configured such that, when the movable lock slides to the second position, the protrusion is aligned with and is biased to enter said recess.
8. A helmet according to claim 3, wherein a first part of the movable lock is fixedly secured to said one of the inner shell and outer shell on which the movable lock is mounted; and a second part of the moveable lock may be inserted into said recess in the other of the inner shell and the outer shell by deforming part of the moveable lock.
9. A helmet according to any one of claims 2 to 8, wherein said movable lock is mounted at the edge of the inner and outer shells.
10. A helmet according to any one of claims 2 to 9, comprising a plurality of said movable locks.
11. A helmet according to claim 10, wherein a first of said plurality of moveable locks restricts movement of the inner shell relative to the outer shell in a first direction; and a second of said plurality of moveable locks restricts movement of the inner shell relative to the outer shell in a second direction, different from said first direction.
12. A helmet according to claim 1, wherein the switch comprises an interface engagement lock configured such that, in the second mode, it fixes a portion of an outer surface of the inner shell to a portion of an inner surface of the outer shell such that the interface engagement lock prevents relative sliding between the portion of the surface of inner shell and the portion of the surface of the outer shell.
13. A helmet according to claim 12, wherein the interface engagement lock comprises a friction pad mounted on one of the inner shell and outer shell; and
the interface engagement lock is configured such that, in the second mode, the friction pad contacts the other of the inner shell and the outer shell with sufficient force that the friction prevents relative sliding between the inner shell and the outer shell.
14. A helmet according to claim 13, wherein the interface engagement lock comprises a rotating actuator that, on rotation in respective first and second directions, retracts and advances the friction pad in order to switch the interface engagement lock between the first and second modes, respectively.
15. A helmet according to claim 13, wherein the interface engagement lock comprises a push button switch that, when pressed, advances the friction pad in order to set the interface engagement lock to the second mode.
16. A helmet according to claim 1, wherein the switch comprises a connector for connecting the inner shell and the outer shell; and the connector is configured such that, in the first mode, it permits relative sliding between the inner shell and the outer shell.
17. A helmet according to claim 16, wherein the switch further comprises a removable insert member;
in the first mode, the insert member is positioned such that no part of the insert member is engaged with the connector; and
in the second mode, the insert member is engaged with the connector such that the connector no longer allows relative sliding between the inner shell and the outer shell at the sliding interface.
18. A helmet according to any one of the preceding claims, wherein the switch is configured to be manually switchable between the first and second modes by a wearer of the helmet.
19. A helmet according to any one of the preceding claims, wherein the switch is configured to be switchable without requiring the use of a tool.
20. A helmet according to any one of the preceding claims, wherein the inner shell is configured to contact the head of the wearer, and the outer shell is an energy absorbing shell for absorbing impact energy.
21. A helmet according to any one of claims 1 to 19, wherein the inner shell is a first energy absorbing shell for absorbing impact energy and the outer shell is a second energy absorbing shell for absorbing impact energy. 22. A helmet according to any one of claims 1 to 19, wherein the inner shell is an energy absorbing shell for absorbing impact energy and the outer shell is a hard shell formed from a hard material relative to a material forming the energy absorbing shell.
Helmets are also common in sporting activities. For example, protective helmets may be used in ice hockey, cycling, motorcycling, motor-car racing, skiing, snow-boarding, skating, skateboarding, equestrian activities, American football, baseball, rugby, cricket, lacrosse, climbing, golf, airsoft and paintballing.
Helmets can be of fixed size or adjustable, to fit different sizes and shapes of head. In some types of helmet, e.g. commonly in ice-hockey helmets, the adjustability can be provided by moving parts of the helmet to change the outer and inner dimensions of the helmet. This can be achieved by having a helmet with two or more parts which can move with respect to each other. In other cases, e.g. commonly in cycling helmets, the helmet is provided with an attachment device for fixing the helmet to the user’ s head, and it is the attachment device that can vary in dimension to fit the user’s head whilst the main body or shell of the helmet remains the same size. In some cases, comfort padding within the helmet can act as the attachment device. The attachment device can also be provided in the form of a plurality of physically separate parts, for example a plurality of comfort pads which are not interconnected with each other. Such attachment devices for seating the helmet on a user’s head may be used together with additional strapping (such as a chin strap) to further secure the helmet in place. Combinations of these adjustment mechanisms are also possible.
Helmets are often made of an outer shell, that is usually hard and made of a plastic or a composite material, and an energy absorbing layer called a liner. Nowadays, a protective helmet has to be designed so as to satisfy certain legal requirements which relate to inter alia the maximum acceleration that may occur in the centre of gravity of the brain at a specified load. Typically, tests are performed, in which what is known as a dummy skull equipped with a helmet is subjected to a radial blow towards the head. This has resulted in modem helmets having good energy- absorption capacity in the case of blows radially against the skull. Progress has also been made (e.g. WO 2001/045526 and WO 2011/139224, which are both incorporated herein by reference, in their entireties) in developing helmets to lessen the energy transmitted from oblique blows (i.e. which combine both tangential and radial components), by absorbing or dissipating rotation energy and/or redirecting it into translational energy rather than rotational energy.
As discussed in the above-referenced patent applications, helmets have been developed in which a sliding interface may be provided between two shells of the helmet in order to assist with management of an oblique impact. However, the present inventors have identified that, in some situations, in particular those during which the wearer of the helmet is not exposed to the more serious risks for which the helmet is designed, the sliding of one part of the helmet to another may inconvenience the user, in particular if the extent of sliding of one part to another becomes too large.
The present invention aims to at least partially address this problem.
According to the present invention, there is provided a helmet comprising an inner shell, and outer shell, and a sliding interface between the inner shell and the outer shell. The helmet further includes a switch, configured to be selectively switchable between first and second discrete modes. In the first mode, relative sliding between the inner shell and the outer shell at the sliding interface in response to an impact to the helmet may be permitted. In the second mode, sliding between the inner shell and the outer shell at the sliding interface in response to an impact to the helmet may be prevented.
The invention is described below by way of non-limiting examples, with reference to the accompanying drawings, in which: Fig.l depicts a cross section through a helmet for providing protection against oblique impacts;
Figs 3 A, 3B & 3C show variations of the structure of the helmet of Fig. 1;
Fig. 4 is a schematic drawing of a another protective helmet;
Fig. 5 depicts an alternative way of connecting the attachment device of the helmet of Fig. 4;
Fig. 6 depicts an arrangement of a moveable lock;
Fig. 7 depicts an arrangement of a moveable lock;
Fig. 8 depicts an arrangement of a moveable lock;
Fig. 9 depicts an arrangement of a moveable lock;
Fig. 10 depicts an arrangement of a moveable lock;
Fig. 11 depicts an arrangement of a moveable lock;
Fig. 12 depicts an arrangement of an interface engagement lock;
Fig. 13 depicts an arrangement of an interface engagement lock;
Fig. 14 depicts an arrangement in which a lock is provided in conjunction with a connector between two shells of a helmet and;
Fig. 15 depicts and arrangement in which a connector between two shells of a helmet includes an integrally formed switch.
Arranged between the outer shell 2 and the inner shell 3 is a sliding layer 4 or a sliding facilitator, and thus makes possible displacement between the outer shell 2 and the inner shell 3. In particular, as discussed below, a sliding layer 4 or sliding facilitator may be configured such that sliding may occur between two parts during an impact. For example, it may be configured to enable sliding under forces associated with an impact on the helmet 1 that is expected to be survivable for the wearer of the helmet 1. In some arrangements, it may be desirable to configure the sliding layer or sliding facilitator such that the coefficient of friction is between 0.001 and 0.3 and/or below 0.15.
Inner shell 3 is designed for absorbing the energy of an impact. Other elements of the helmet 1 will absorb that energy to a limited extend (e.g. the hard outer shell 2 or so- called‘comfort padding’ provided within the inner shell 3), but that is not their primary purpose and their contribution to the energy absorption is minimal compared to the energy absorption of the inner shell 3. Indeed, although some other elements such as comfort padding may be made of‘compressible’ materials, and as such considered as‘energy absorbing’ in other contexts, it is well recognised in the field of helmets that compressible materials are not necessarily‘energy absorbing’ in the sense of absorbing a meaningful amount of energy during an impact, for the purposes of reducing the harm to the wearer of the helmet.
A number of different materials and embodiments can be used as the sliding layer 4 or sliding facilitator, for example oil, Teflon, microspheres, air, rubber, polycarbonate (PC), a fabric material such as felt, etc. Such a layer may have a thickness of roughly 0.1-5 mm, but other thicknesses can also be used, depending on the material selected and the performance desired. The number of sliding layers and their positioning can also be varied, and an example of this is discussed below (with reference to Fig. 3B).
Other arrangements of the protective helmet 1 are also possible. A few possible variants are shown in Fig. 3. In Fig. 3a, the inner shell 3 is constructed from a relatively thin outer layer 3" and a relatively thick inner layer 3'. The outer layer 3" is preferably harder than the inner layer 3', to help facilitate the sliding with respect to outer shell 2. In Fig. 3b, the inner shell 3 is constructed in the same manner as in Fig. 3a. In this case, however, there are two sliding layers 4, between which there is an intermediate shell 6. The two sliding layers 4 can, if so desired, be embodied differently and made of different materials. One possibility, for example, is to have lower friction in the outer sliding layer than in the inner. In Fig. 3c, the outer shell 2 is embodied differently to previously. In this case, a harder outer layer 2" covers a softer inner layer 2'. The inner layer 2' may, for example, be the same material as the inner shell 3.
However, it is equally conceivable that the sliding facilitator 4 may be provided on or integrated with the outer surface of the attachment device 13, for the same purpose of providing slidability between the energy absorbing layer 3 and the attachment device 13. That is, in particular arrangements, the attachment device 13 itself can be adapted to act as a sliding facilitator 4 and may comprise a low friction material.
The attachment device 13 can be fixed to the energy absorbing layer 3 and / or the outer shell 2 by means of fixing members 5, such as the four fixing members 5a, 5b, 5c and 5d in Fig. 4. These may be adapted to absorb energy by deforming in an elastic, semi elastic or plastic way. However, this is not essential. Further, even where this feature is present, the amount of energy absorbed is usually minimal in comparison to the energy absorbed by the energy absorbing layer 3 during an impact.
Fig. 5 shows an embodiment of a helmet similar to the helmet in Fig. 4, when placed on a wearers’ head. The helmet 1 of Fig. 5 comprises a hard outer shell 2 made from a different material than the energy absorbing layer 3. In contrast to Fig. 4, in Fig. 5 the attachment device 13 is fixed to the energy absorbing layer 3 by means of two fixing members 5a, 5b, which are adapted to absorb energy and forces elastically, semi-elastically or plastically.
In an arrangement of the present invention, a helmet is provided with a switch configured to be selectively switchable between two discrete modes. In the first mode, relative sliding between an inner shell and an outer shell of the helmet may be possible in response to an impact to the helmet. In the second mode, relative sliding between the inner shell and the outer shell is prevented. The inner and outer shells of the helmet for which the switch controls relative sliding may, in general, be any two layers of a helmet between which a sliding interface is provided. In particular, such a switch may be provided to any of the helmet arrangements discussed above.
For example, in an arrangement, the inner shell may be a layer that is configured to contact the head of the wearer and/or to be mounted to the head of the wearer and the outer shell may be an energy absorbing layer for absorbing impact energy. In another arrangement, the inner shell may be a first energy absorbing layer for absorbing impact energy and the outer shell may be a second energy absorbing layer for absorbing impact energy. In a further example, the inner shell may be an energy absorbing layer for absorbing impact energy and the outer shell may be a relatively hard shell, for example formed from a material that is harder than the material used to form the energy absorbing layer.
As is explained below in relation to specific examples of arrangements of the switch, the switch may be configured such that it can be manually switched between the first and second modes by a wearer of the helmet. Accordingly, the switching between the first and second modes may be performed after a user has purchased a helmet rather than being set, for example, in the manufacturing/assembly process. A user may also be able to repeatedly switch backwards and forwards between the first and second modes.
In some arrangements, a tool may be used in order to complete switching between the first and second modes. In other arrangements, the switch may be configured such that the user can switch between the first and second modes without requiring the use of a tool. For example, the switch may be configured such that switching between the first and second modes may be effected using their hands/fingers.
In general, a switch may be provided at any convenient point on a helmet. In some arrangements, the switch may be provided at the edge of a helmet. This may be convenient for providing access for a user to the switch. For example, this may permit the user to switch between the first and second modes while wearing the helmet. Alternatively or additionally, providing a switch at an edge of a helmet may facilitate the manufacture of a helmet with such a switch.
Figure 6 depicts an example of a helmet having a switch 20 provided at an edge of a helmet. In the arrangement shown, the helmet includes an outer shell 21 and an inner shell 22 with a sliding interface 23 provided between the two shells. The switch 20 includes a moveable lock 25 that can move between first and second positions that correspond to the first and second modes of the switch 20.
Figure 6 depicts the lock 25 in the first position. As shown, The lock 25 is mounted to the outer shell 21 by a rotatable mounting point 26. In the first position, the lock 25 is not engaged with the inner shell 22. Consequently, the inner shell 22 may slide relative to the outer shell 21 at the sliding interface.
The lock 25 may be moved to the second position by rotating the lock 25 about the rotatable mounting point 26. When the lock 25 is rotated to the second position, an end 28 of the lock 25 engages with a recess 27 within the inner shell 22. The engagement of the lock 25 with the inner shell 22 may be configured to prevent movement of the inner shell 22 relative to the outer shell 21. In this way, relative sliding between the inner shell 22 and the outer shell 21 at the sliding interface 23 may be prevented, setting the switch 20 to the second mode.
It should be appreciated that variations of the arrangement shown in Figure 6 may be provided. For example, the lock 25 may be rotatably mounted to the inner shell and configured such that it can engage with, and disengage from, the outer shell. Alternatively or additionally, the end of the lock may be configured to engage with the shell to which it is not mounted by a means other than by entering a recess in that shell. For example, the moveable lock may be configured to engage with a protrusion that protrudes from the shell. In general, a variety of forms of detachable connection may be provided between the lock and the shell other than the shell to which it is mounted.
In an arrangement, the moveable lock 20 may be configured such that it can engage with the shell other than the shell to which it is mounted in order to prevent relative sliding between the shells without requiring a part of the lock to be inserted within a recess. For example, in the arrangement depicted in Figure 7, the lock 20 may include a tab 29 that is rotatably mounted on the edge of the outer shell 21. In a first position, the tab 29 may be arranged adjacent to the outer surface of the outer shell 21. In the second position, the tab 29 may abut the edge of the inner shell 22, preventing the inner shell 22 from sliding relative to the outer shell 21.
As shown in Figure 7, although in such an arrangement the rotatably mounted tab 29 may engage with the inner shell 22 without being inserted into a recess in the inner shell 22, a shallow recess may in any case be provided to receive the tab 29 in the second position. For example, this may reduce the likelihood of the tab 29 being accidentally flipped back to the first position.
Figures 8 and 9 depict alternative arrangements of a moveable lock 20. The arrangements shown in Figures 8 and 9 differ from the arrangement shown in Figure 6 in that the lock 20 includes a component that is slidably mounted to the outer shell 21 rather than rotatably mounted as in the arrangement shown in Figure 6.
In this context, a slidably mounted component may be one that is arranged such that it can move in a substantially linear direction approximately parallel to the surface of the shell to which it is mounted. It will be appreciated that the movement may not be perfectly linear, namely in a straight direction, because it may correspond to the local curvature of the shell of the helmet. In the arrangement shown in Figures 8 and 9, the slidably mounted components 31, 35 are mounted to the outer shell 21. However, with appropriate modifications it will be appreciated that these components may alternatively be mounted to the inner shell 22.
In arrangement such as that depicted in Figure 8, the lock 20 may have a protrusion 32 connected to the slidably mounted component 31 that is arranged such that, as the lock 20 is moved from the first position to the second position and back again, the protrusion 32 is inserted into, and withdrawn from, respectively, a recess 33 within the inner shell 22.
As shown, the protrusion 32 is arranged such that, at least when it is inserted into the recess 33, it extends at an angle relative to the direction in which the slidably mounted component 31 moves when it is moved between the first and second positions. In a corresponding manner to the arrangement discussed above shown in Figure 6, when the protrusion 32 is inserted into the recess 33, it engages with the inner shell 22 in order to restrict movement of the inner shell 22 relative to the outer shell 21.
The arrangement depicted in Figure 9 operates in a similar manner to the arrangement shown in Figure 8, having a protrusion 36 connected to the slidably mounted component 35 that, upon operation of the lock 20 may be inserted into, and retracted from, a recess 37 within the inner shell 22.
The key functional difference between the arrangement depicted in Figures 8 and 9 are that, in the arrangement depicted in Figure 8, sliding the slidably mounted component 31 in a direction from the top of the helmet to the edge of the helmet moves the lock 20 to the first position whereas, in the arrangement depicted in Figure 9, moving the slidably mounted component 35 in a direction from the top of the helmet to the edge of the helmet moves the switch 20 to the second position.
Figure 10 depicts a further alternative arrangement of a slidably mounted lock 20. As shown, in this arrangement, the lock 20 includes a slidably mounted component 40, mounted on the outer surface of the outer shell 21, that includes a protrusion 41. In the arrangement depicted, when the slidably mounted component 40 is moved to the second position, the protrusion 41 passes through an opening 42 in the outer shell 21 and enters a recess 43 in the inner shell 22. The presence of the protrusion 41 within the recess 43 in the inner shell 22 may restrict sliding movement between the inner shell 22 and the outer shell 21.
The lock 20 may be configured such that the protrusion 41 is biased towards passing through the opening 42 in the outer shell 21 and entering the recess 43 in the inner shell 22 when the slidably mounted component 40 is moved to the second position. In an arrangement, this may be provided by providing a resilient member 44 between the slidably mounted component 40 and the protrusion 41 that biases the protrusion 41 towards the recess 43.
Alternatively or additionally, the slidably mounted component 40 may itself be resilient and arranged such that, in the first position, the slidably mounted component is deformed and presses the protrusion 41 against the outer surface of the outer shell 21. Once the protrusion 41 is aligned with the opening 42, the slidably mounted component 40 is biased to return to its undeformed state, forcing the protrusion 41 through the opening 43 and into the recess 43.
As shown in Figure 10, in one arrangement, the surface of the protrusion 41 that engages with the inner shell 22 may have a rounded edge such that, as the slidably mounted component 40 is pushed back to the first position, namely slid in a substantially linear direction parallel to the surface of the outer shell in the region of the opening 42, the protrusion 41 is withdrawn from the recess 43 in the inner shell 22 and through the opening 42 in the outer shell 21. In other words, the engagement of the rounded edge of the protrusion with the edge of the recess 43 and/or opening 42 may force the protrusion in a direction substantially perpendicular to the surface of the outer shell 21 in the region of the opening 42. This may overcome the force biasing the protrusion into the recess 43.
In an arrangement, the moveable lock 20 may have a first part 51 mounted to one of the inner shell and the outer shell and a second part 52 that may be inserted into a recess 53 in the other shell by deforming a part of the lock 20.
Figure 11 depicts such an arrangement. In the arrangement depicted in Figure 11, the first part 51 of the lock 20 is mounted to the inner shell 22. A second part 52 of the lock 50 may be inserted into a recess 53 in the outer shell 21. This may be effected by deformation of part of the lock 20, in particular, for example, a part of the lock between the first part 51 and second part 52. By insertion of the second part 52 of the lock 20 into the recess 53, sliding of the inner shell 22 relative to the outer shell 21 may be restricted.
It will be appreciated that, although in the arrangement depicted in Figure 11 the first part 51 is mounted to the inner shell and the lock 20 is configured such that the second part 52 may be inserted in a recess 53 in the outer shell 21, this arrangement may be reversed. Similarly, it will be appreciated that, although Figure 11 depicts an example of a lock applied to a helmet in which the inner shell 22 is relatively thin, for example configured to mount the helmet to the head of the wearer, and the outer shell 21 is an energy absorbing layer that is thicker than the inner shell 22, as with the other
arrangements discussed above, this moveable lock may equally be applied to other helmet configurations.
In an arrangement, a helmet may have a plurality of locks 20 such as any of those discussed above. A helmet may have a plurality of locks 20 of one arrangement or may have plural locks constructed according to two or more of the arrangements discussed above.
In some arrangements, a single lock may, when in the second position, restrict movement of the inner shell relative to the outer shell in a first direction. The helmet may include a second lock that, when it is in its second position, restricts movement of the inner shell relative to the outer shell in a second direction that is different from the first direction.
For example, a helmet may have one or more locks that, in the second position, restrict rotation of the outer shell relative to the inner shell about an axis that extends from the front to the back of the head of the wearer and one or more locks that, in the second position, restrict rotation of the outer shell relative to the inner shell about an axis that extends from one side to a second side of the head of the wearer.
In an arrangement, a helmet may include a switch that comprises an interface engagement lock 60. The interface engagement lock 60 may be configured such that, in the second mode, it secures part of an outer surface of the inner shell 22 to a portion of the inner surface of the outer shell 21. This engagement between the surfaces of the inner shell 22 and the outer shell 21 may be configured to prevent sliding between the respective portions of the surfaces of the inner shell 22 and the outer shell 21. In turn this may restrict sliding of the inner shell 22 relative to the outer shell 21.
Figure 12 depicts an arrangement of an interface engagement lock 60. In the arrangement depicted in Figure 12, the interface engagement lock 60 includes a friction pad 61 that is mounted to the inner shell 22. The interface engagement lock 60 is arranged such that, in the first mode, the friction pad 61 either has no contact with the inner surface of the outer shell 21 or contacts it with sufficiently small force that the friction force between the friction pad 61 and the inner surface of the outer shell 21 does not
significantly prevent sliding of the outer shell 21 relative to the inner shell 22 in the event of an impact to the helmet for which the helmet is designed. In the second mode, the friction pad 61 is pressed against the inner surface of the outer shell 21 such that a sufficient friction force is provided between the friction pad 61 and the inner surface of the outer shell 21 that sliding of the outer shell 21 relative to the inner shell 22 is prevented in at least normal use of the helmet.
In the arrangement depicted in Figure 12, a rotating actuator 62 is provided to adjust the position of the friction pad 61 and/or the reaction force between the friction pad 61 and the inner surface of the outer shell 21. The rotating actuator 62 may be rotated between a first position, in which the switch operates in the first mode, and does not restrict relative sliding between the outer shell 21 and the inner shell 22, and the second mode, in which relative sliding is restricted.
The rotating actuator 62 may include finger holes (not shown in Figure 12) to enable the user to rotate the rotating actuator between first and second positions.
Alternatively or additionally, the rotating actuator 62 may be configured to receive a tool that a user may use in order to turn the rotating actuator 62. Any of any variety of configurations may be used to convert the rotary motion of the rotating actuator 61 into a linear motion that advances and retracts the friction pad 61, including for example a screw thread.
Figure 13 depicts a variation of the arrangement shown in Figure 12. In this arrangement, the friction pad 61 is driven by a push button 63. The push button
mechanism may be configured such that, when first pressed, it advances the friction pad 61 towards the outer shell 21 in order to set the interface engagement locks 60 to the second mode, restricting sliding of the outer shell 21 relative to the inner shell 22. The push button mechanism may be further configured such that, when pressed a second time, the friction pad 61 is retracted from the outer shell 21, setting the interface engagement lock to the first mode.
As discussed above, one or more connectors may be provided between the first and second shell of a helmet that is configured to permit sliding between the two shells in the event of an impact on the helmet. Such connectors may be configured to permit sliding between the two shells in the event of a substantial impact but may minimise or reduce movement between the shells in the absence of an impact and/or may be configured to prevent the two shells from separating in the absence of an impact. In an arrangement, the switch that is configured to switch between first and second modes enabling and restricting sliding of the inner shell relative to the outer shell of the helmet, may include such a connector. Although such a connector may be configured to prevent the inner shell and the outer shell from separating in the absence of an impact, the connector may permit relative sliding in the event of an impact to the helmet.
Figure 14 depicts an arrangement in which a connector 71 is combined with a switch 72. In the arrangement shown, the connector 71 is provided by elongate resilient components connected at a first end 73 to one shell of the helmet and at the second end 74 to another shell of the helmet. During relative sliding of the two shells, the resilient elements flex, permitting the separation between the first and second ends 73, 74 of the connector 71 to change, in turn permitting relative sliding of the two shells.
As shown, the lock 72 associated with the connector 71 may be arranged such that it is mounted at one end 73 of the connector to one of the shells of the helmet. The lock 72 is further configured such that it can be switched between a first position, in which it does not engage with the helmet shell 75 other than the shell to which it is mounted, and a second position, in which the lock 72 engages with the shell other than the one to which it is mounted such that the lock 72 prevents movement between the first and second ends 73, 74 of the connector 71. Accordingly, in the second position, the lock 72 prevents relative sliding of the two shells of the helmet. In the arrangement shown in Figure 14, the lock 72 is configured as a rotatably mounted lock 72 that engages with a recess 76 in the opposing shell 75. However, it should be appreciated that, with appropriate modifications, any of the lock arrangements discussed above may be used in combination with a connector.
In an arrangement, the switch may be configured such that, rather than being merely provided in conjunction with a connector 71, the switch is integrally formed with the connector. In particular, the switch may be configured such that, in the first mode the connector functions unimpeded but, in the second mode, the switch prevents the connector from functioning in a way that permits relative sliding of the shells of the helmet.
Such an arrangement may be provided, for example, in an arrangement such as that depicted in Figure 15, in which the connector 71 is formed from a plurality of elongate resilient elements that, under loading, may deform to permit movement between a first part 77 of the connector 71, mounted to a first helmet shell 76, and one or more parts 78, connected to a second shell 75. The switch may comprise one or more removable inserts 79 that may fill the space between the first part 77 of the connector 71 and the second part of the connector 78.
The one or more removable inserts 79 may be stiffer than the resilient elements forming the connector such that it prevents movement between the first and second parts 77, 78 of the connector 71, namely prevents the resilient elements from deforming.
In the first mode, the one or more insert members 79 may be positioned such that they do not engage with the connector 71 and therefore do not prevent movement between the first and second ends 77, 78 of the connector. Accordingly, sliding between the helmet shells may not be restricted.
In the second mode, the one or more insert members 79 engage with the connector 71 such that the first and second parts 77, 78 may not move relative to one another, which restricts sliding between the two shells of the helmet.
It should be appreciated that, although the arrangement depicted in Figure 15 appears to show a plurality of insert members 79, these may be connected together above the plane of the figure in order to provide a single insert member that may be inserted into, and removed from, the connector by a user. It should also be appreciated that, in the first mode, the one or more insert members may be retained in the helmet and/or connector in a position that does not prevent relative movement of the first and second parts 77, 78 of the connector. Alternatively, the one or more insert members 79 may be configured such that, in the first mode, the user completely removes the one or more insert members from the helmet.
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