Patent Publication Number: US-9833074-B2

Title: Functional chair

Description:
RELATED APPLICATIONS 
     This application is a national phase of International Patent Application No. PCT/EP2013/000702, filed Mar. 8, 2013, which claims the filing benefit of German Patent Application No. 10 2012 002 288.1, filed Mar. 8, 2012, the contents of both of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a functional chair having a foot part and a seat part with a supporting mechanism which connects the seat part to the foot part. 
     BACKGROUND OF THE INVENTION 
     Functional chairs of this kind are known in varying form of embodiment. They offer possibilities for setting the position and orientation of the seat and of parts of the latter, with the aim of making it possible to sit in a variable and fatigue-free manner. 
     In functional chairs of this kind, a seat-surface section and a backrest section of the seat are, as a rule, capable of being displaced and set in relation to one another. 
     This leads to the occurrence, at the rear end of the seat-surface section and at the lower end of the backrest section, of translatory relative movements which are perceived as unpleasant. 
     SUMMARY OF THE INVENTION 
     An intention of the present invention is to further develop a functional chair of the kind initially discussed, in such a way, by means of the present invention, that it continues to make it possible to set the seat but, on the other hand, without any translatory relative movements taking place in the transitional region between the seat-surface section and the backrest section. 
     This object may be achieved, according to the invention, by means of a functional chair having a supporting mechanism which has: a cantilever part which is connected to the foot part by an internally located end and which extends away from the foot part with a radial component of extension, a supporting part which is attached in an articulated manner to the cantilever part at a point which is remote from the ends of the cantilever part and is connected, by a free end, to a region of a seat part which is distant from a front edge of the seat part, and a sliding mounting which is provided at the free end of the cantilever part and via which a section of the seat part which is adjacent to the front edge of the seat part is carried by the cantilever part. 
     In the functional chair according to the invention, a substantially constant relative position and relative inclination exists between the seat-surface section and the backrest section. This constant relationship would be provided in a precise manner if the seat-surface section and the backrest section were manufactured from rigid material. If they are manufactured from elastically deformable material, minor changes in the angle included between the seat-surface section and the backrest section can take place against spring force. 
     With the aid of the functional chair according to the invention it is possible to lower the rear end of the seat-surface section, with the front edge of said seat-surface section remaining substantially at the same height. The backrest section is inclined with said seat-surface section, in accordance with the angular adjustment of the latter. 
     As a result of the mechanism indicated, the desired setting of the seat can be carried out reliably and with simple means. 
     Advantageous further development of the invention form the subject of additional aspects of the invention. 
     What is achieved by means of the further development of the invention according to another aspect of the invention is that the seat is satisfactorily supported by the supporting part, even against tipping movements about an axis extending in the direction of the depth. Under these circumstances, a connection between the free ends of the supporting arms makes it possible to guarantee support having a strong load-bearing capacity, while using little material. 
     The further development of the invention according to another aspect of the invention makes it possible to fasten a backrest part to the supporting part in a simple manner. 
     In a functional chair according to another aspect of the invention, armrest parts can be attached in a very simple manner. Under these circumstances, the space located under the armrest part is free, so that jackets cannot get caught at that point. 
     In a functional chair according to an additional aspect of the invention, the sliding bearing, and thereby the front section of the seat part, is satisfactorily protected against tilting. 
     In a functional chair according to yet another aspect of the invention, the seat can be moved, against spring force, out of its normal position in which its seat-surface part is oriented approximately horizontally. 
     By means of the further development of the invention according to another aspect, a sliding bearing which is simple and capable of bearing loads is obtained for the seat part. 
     In a functional chair according to another aspect of the invention, the pin-and-slot connection which is already provided for guiding the front end of the seat part may also serve to lock the seat in its normal position with the seat surface extending approximately horizontally. 
     By means of the further development of the invention according to another aspect, a secure connection between the sliding bearing and the seat is obtained. 
     Under these circumstances, a settable restoring force for the seat part is obtained in a very simple manner according to another aspect of the invention. 
     The further development of the invention according to another aspect of the invention is advantageous with respect to identical support for the two lateral regions of the front section of the seat part. If, under these circumstances, the free ends of the cantilever arms are connected by a cross-piece, there is once again obtained, while using little material, a framework which is suitable for absorbing major forces. 
     In a functional chair according to another aspect of the invention, the cross-piece connecting the cantilever arms may serve, at the same time, as a spring seat and a base part for fitting-on further elements of the chair. 
     What is achieved by means of the further development of the invention according to another aspect of the invention is that the seat-surface part is able to deform elastically somewhat when the seat is subjected to load and lowered. By this means, the rear section of the seat-surface part can be inclined to a greater extent, while the front section of said seat-surface section is tilted only a little. This is advantageous with respect to avoiding pressure loadings on that region of the user&#39;s thigh which is adjacent to the knee. 
     The further development of the invention according to yet another aspect of the invention also serves for the user&#39;s comfort, since the seat surface is softer in the region of a user&#39;s ischial tuberosities. 
     It is to be understood that the aspects and objects of the present invention described above may be combinable and that other advantages and aspects of the present invention will become apparent upon reading the following description of the drawings and detailed description of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in greater detail below with the aid of an exemplary embodiment and with reference to the drawings, in which: 
         FIG. 1  shows a lateral view of a functional chair in a non-loaded normal position (in solid lines) and a lowered rest position (in broken lines); 
         FIG. 2  shows a vertical section through a seat-surface part of the functional chair according to  FIG. 1 , together with a supporting mechanism via which the seat part is mounted on a foot part of said functional chair; 
         FIG. 3  shows a similar view to that in  FIG. 1 , showing details of a sliding mounting for the front end of the seat part and details of a fastening of the rear end of said seat part to the supporting mechanism; 
         FIG. 4  shows a perspective plan view of the underside of the seat part, viewed obliquely from behind; 
         FIG. 5  shows a perspective plan view of the underside of the seat part, viewed obliquely from the front; and 
         FIG. 6  shows a perspective plan view of the front side of a modified functional chair without cushions. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. 
     In the present description and the claims, use is made of various indications of direction; these relate to an observer standing in front of the functional chair. The direction of the width therefore extends perpendicularly to the plane of the drawing in  FIG. 1 . The direction of the depth extends from left to right in  FIG. 1 , and the direction of the height extends from bottom to top in  FIG. 1 . 
       FIG. 1  shows a functional chair which has, as its main components, a foot part  10 , a seat part  12  and also a supporting mechanism  14 , via which said seat part  12  is connected to said foot part  10 . 
     Typically, there are also attached to the seat part  12  a back cushion  16  and a seat cushion  18 , which cushions are indicated only diagrammatically in outline. 
     The foot part  10  has a foot-spider  20  with castors  22 . The centre of the foot-spider  20  carries a vertical tube  24 . 
     The supporting mechanism  14  comprises a cantilever arm  26  whose lower end, which is located on the inside radially, is seated in a rotatable manner on the upper end of the vertical tube  24 . Said cantilever arm  26  extends obliquely leftwards and upwards in  FIG. 1 . Via a sliding mounting, which is designated as a whole by  30 , the free end of the cantilever arm  26  carries a front section of the seat part  12 . 
     Approximately in the middle of the cantilever arm  26 , a supporting part  34  is attached in an articulated manner via a pivot bearing  32 . As can be seen particularly from  FIGS. 4 and 5 , the supporting part  24  comprises two supporting arms  36 ,  38  which extend away from the axis of the foot part and the free ends of which are connected by a connection-carrier  40  to form an isosceles triangle. As can be seen from  FIG. 5 , said connection-carrier  40  has a slightly arcuate geometry. 
     Similarly, the cantilever part  26  has two cantilever arms  42 ,  44  which extend away from the axis of the foot part  10  in a diverging manner and are connected at their free ends by a cross-piece  46 . There is thus obtained, once again, a triangular framework which has a good load-bearing capacity, even while using little material. 
     For its part, the seat part  12  has a seat-surface section  48  which extends approximately horizontally when in the normal position and in which a bending section  50  is provided at approximately two thirds of its extension in terms of depth. This section is provided in the shape of a number of adjacent transverse triangular grooves  52 . 
     As can be seen particularly from  FIGS. 2, 4 and 5 , a bearing strip  54  extends in the direction of the width (the transverse direction) at a point on the seat-surface section  48  which amounts to about 20 to 25% of its dimension in depth. Said bearing strip  54  has a foot section which has a rectangular cross-section and is seated in a complementary depression  56  constructed in the underside of the seat-surface section  48 . Lateral ribs  58 ,  60  belonging to the bearing strip  54 , which have a triangular cross-section, overlap the edges of the depression  56 . 
     Slots  64  are constructed in end sections  62  of the bearing strip  54  which hang down at the sides. Engaging in said slots is a guide pin  64  which is carried by a bearing tab  66  belonging to the cantilever part  26 , which bearing tab is raised at the sides. 
     The bearing tab  66  is, at the same time, located with slight clearance opposite the end section  62  of the lattice strip  54  in which the slot  64  is constructed. 
     As can be seen particularly from  FIG. 2 , the supporting part  34  has a formed-on driving lever  68  which works on a spring cartridge which is designated, as a whole, by  70 . 
     Said spring cartridge comprises a cup-shaped housing  72  which has a central tubular section  74 . A helical compression spring  76  is arranged in the annular space which lies between the tubular section  74  and the peripheral wall of the housing  72 . Said spring acts upon a spring seat  78  which is connected to the end of the driving lever  68  in an articulated manner via a pin  80 . 
     The spring seat  78  has a guide bar  82  which extends within the interior of the tubular section  74 . 
     The base of the housing  72 , which base is located on the left in  FIG. 2 , is provided with a threaded bush  84  within which a setting screw  86  can be adjusted. 
     At its end that lies outside the spring cartridge  70 , the setting screw  86  has a strip-shaped head section with a circular cross-section which serves as a rolling bearing. The appertaining bearing seat is formed by two legs  90 ,  92  of the cross-piece  46  as well as a prismatic masking part  94  with a triangular cross-section, which part is carried by the upper end of the leg  92 . 
     As can be seen from  FIG. 3 , that end of the supporting part  34  which is located on the right in the drawing is provided with a stepped contact surface  96  for the rear end of the seat-surface section  50  which is fixed at that point by means of screws  98 . 
     That end of the connection-carrier  40  which is located on the right in  FIG. 3  is provided, at its centre, with a projecting tongue  100  which is capable of cooperating with a complementary clearance  102  which is constructed in an insert  104  embedded in the lower end of a backrest section  105 . 
     The supporting part  34  has laterally protruding projections  106  which are formed on at the two sides of the rear connection-carrier  40  and which combine with clearances  108  provided in armrest parts  110  to form a push-in connection. In this way, the armrest parts  110  can be easily taken off and put on. 
     A locking pin  112 , which can be moved in and out of the track of a slot  64  by a slide  114  ( FIG. 4 ), is provided for locking the seat part  14  in the normal position. Said locking pin  112  is indicated in outline in broken lines in  FIG. 3 . 
     For the purpose of setting the spring pretensioning for the seat part  12 , the outside of the housing  72  of the spring cartridge  70  is provided with knurling or a friction coating. It is thus possible to set the pretensioning of the helical compression spring  76  by rotating the housing  72  (with the setting screw  86  fixed in the direction of rotation). 
     The functional chair described above can be packed in a compact manner, since the backrest section  105  and the seat-surface section  48  can be easily mounted on, and demounted from, the supporting part  34 . 
     The supporting mechanism described permits sitting both in an upright manner and in a backwardly inclined manner. In the course of transition between the two sitting positions, no appreciable relative movement occurs between the seat-surface section  48  and the backrest section  105 . 
     The mechanism described is of simple and robust design. 
     The parts of the supporting mechanism  14  may be predominantly injection-moulded parts made of aluminium or an aluminium alloy. The seat part  12  and its seat-surface section  48 , as well as its backrest section  105 , may be moulded parts which are substantially rigid and exhibit only a slightly resilient behaviour which can be predetermined via the choice of material and the geometry, as is known to the person skilled in the art in the field of moulding plastic parts. As materials, use may preferably be made, for the backrest section, of a polyamide with short glass-fibre reinforcement (preferably PA6 GF 15) and, for the seat-surface section, of a polypropylene. 
     In the case of the slightly modified exemplary embodiment according to  FIG. 6 , only the differences in relation to the exemplary embodiment described above will be explicitly described. The remaining components are to be regarded as similar. The reference numerals in  FIGS. 1 to 5  are also used. 
     The backrest section  105  of the seat part  12  is firmly slipped, by means of lower clearances  102 , onto two lateral radial tongues  100  belonging to the connection-carrier  40 , said clearances being moulded-in at the same time as the backrest section  105  is injection-moulded. 
     Shown on the front side of said backrest section  105  are fastening eyes  118  onto which a back cushion  16  can be pushed, buttoned or latched. The seat-surface part  48  carries similar fastening eyes  120  for a seat cushion  18 . 
     The bending section  50 , which is located on the underside of the seat-surface section  48 , is indicated in outline in broken lines. 
     That part of the seat-surface section  48  which lies behind the bending section  50  is, once again, connected rigidly to the connection-carrier  40  and thus pivots, together with the seat-rest part  105 , while that part of the seat-surface part  48  which lies in front of the bending section  50  may have a different inclination from, and as a rule is less steep than, the part that lies behind said bending section. 
     In the case of a given material for the seat-surface section  48 , it is possible to set the resilient properties of the bending section  50  via the width of the strip-shaped bending section  50  (dimension in the direction from “front” to “back”) and via the depth and cross-sectional shape of the grooves  52 . 
     It is to be understood that additional embodiments of the present invention described herein may be contemplated by one of ordinary skill in the art and that the scope of the present invention is not limited to the embodiments disclosed. While specific embodiments of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.