Abstract:
Hinge mechanism comprising first and second frames rotatably mounted relative to one another, the first frame comprising a collet, a control member rotatably mounted in the collet of the first frame and controlling a relative rotation between the two frames, and a brake unit comprising an operating member connected to the control member with angular play. The brake unit is housed in the collet of the first frame and fitted with a braking member adapted to brake the control member when the operating member is not activated and to allow the operating member to rotationally drive the control member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under the Paris Convention to the French Patent Application No. 10 56279, filed on Jul. 29, 2010. 
     FIELD OF THE INVENTION DISCLOSURE 
     The invention relates to hinge mechanisms and to vehicle seats comprising such mechanisms. 
     More specifically, the invention concerns a hinge mechanism comprising:
         first and second frames rotatably mounted relative to one another, the first frame comprising an end-plate parallel to the second frame and a collet centered around a first axis perpendicular to said end-plate of the first frame,   a control member rotatably mounted in the collet of the first frame and adapted to control the relative rotation between the first and second frames,   a brake unit comprising at least one operating member connected with angular play to the control member and fitted with a braking member adapted to brake the control member when the operating member is not activated and to allow said operating member to drive the control member when said operating member is activated.       

     BACKGROUND OF THE INVENTION DISCLOSURE 
     Document DE-A-10 2008 028 086 describes an example of a hinge mechanism of this type, in which the hinge mechanism consists of:
         a first hinge housing comprising the first and second frames connected together by gears,   and the brake unit, which comprises a second housing laterally attached to the exterior of the first housing.       

     The drawback of this particularly bulky hinge mechanism is the presence of the second attached housing. 
     Another similar mechanism is known from document DE102005028779 but the braking arrangement is not designed as a module and is somewhat bulky. 
     OBJECTS AND SUMMARY OF THE INVENTION DISCLOSURE 
     The purpose of this invention is to overcome this disadvantage. 
     To that end, a hinge mechanism of the invention comprises a friction ring which is press-fitted in the collet of the first frame, the brake unit being at least partially contained in the collet. 
     This avoids an increase in the overall dimensions of the hinge mechanism. 
     In various embodiments of the hinge mechanism of the invention, one or more of the following arrangements may be used:
         the collet is integrally formed with the first frame;   the braking member of the brake unit comprises a brake coil spring having a winding which extends between first and second terminating arms, said winding being centered around the first axis and working by friction with a cylindrical friction surface of the friction ring (the ring attached to the collet or a part of the collet) and is centered around the first axis, said friction surface surrounding the brake coil spring, the operating member comprising unlocking stop elements which act on one of the first and second terminating arms in an angular direction corresponding to a decrease in the diameter of the winding when said operating member is activated to rotate around the first axis, and the control member comprising locking stop elements which act on one of the first and second terminating arms in an angular direction corresponding to an increase in the diameter of the winding when said control member is activated to rotate around the first axis without activation of the operating member;   the operating member is fixed axially to the control member, and the friction ring and brake coil spring are held axially between said operating member and said control member;   the first and second frames are linked together by a gear unit, and said hinge mechanism also comprises an eccentric cam rotatably mounted in the collet of the first frame, the control member being mounted to rotate around a second axis relative to the second frame, said second axis being parallel to the first axis and distinct from said first axis, and the control member being adapted to rotationally drive the eccentric cam;   the gear is hypocycloidal;   the gear comprises first and second circular gear teeth which mutually engage and which are mechanically linked to the first and second frames respectively, said first and second gear teeth being respectively centered around the first and second axis.       

     Another object of the invention is a vehicle seat comprising first and second parts connected by a hinge mechanism as defined above, the first and second frames being attached, one to the first part and other to the second part. The first and second seat parts may possibly a seat bottom and a backrest. The seat advantageously has first and second sides, with said hinge mechanism being arranged on the first side and the second side of the seat comprising an additional hinge mechanism without a brake unit, said additional hinge mechanism comprising:
         first and second frames mounted to rotate relative to each other, one integrally attached to the seat bottom and the other to the backrest,   a control member mounted to rotate relative to the first frame of said additional hinge mechanism, said control member being able to control a relative rotation between the first and second frames, said control member of the additional hinge mechanism being rotationally fixed to said control member of the hinge mechanism situated on the first side of the seat.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given as a non-limiting example and represented in the attached drawings. 
       Concerning the drawings: 
         FIG. 1  is a schematic view of a vehicle seat that can be equipped with a hinge mechanism of the invention, 
         FIGS. 2 and 3  are perspective views of one embodiment of the invention, seen from two opposing directions, showing the hinge mechanism which can be fitted to a first side of the seat in  FIG. 1 ; this hinge mechanism is partially exploded, with its braking module shown outside the collet in which it is normally housed, 
         FIGS. 4 and 5  are exploded perspective views of the hinge mechanism in  FIG. 2 , viewed in the respective directions IV and V in  FIG. 2 , 
         FIG. 6  is an axial cross-sectional view of the hinge mechanism in  FIG. 2  and of an additional hinge mechanism situated on a second side of the seat, 
         FIG. 7  is a view similar to  FIG. 4 , showing the additional hinge mechanism, 
       and  FIGS. 8 and 9  are transverse cross-sectional views of the hinge mechanism in  FIG. 2 , the cross-sections being viewed along the respective lines indicated as VIII-VIII and IX-IX in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     The same references in the different figures denote identical or similar elements. 
       FIG. 1  represents a front seat  1  of an automobile, comprising a backrest  2  mounted to pivot on a seat bottom  3  around an axis Y 1 , with the seat bottom being mounted on the floor  4  of the vehicle, for example by means of rails  5 . 
     The incline of the backrest  2  is manually adjustable using a button or a pivoting control handle  6   a  or similar device which drives a geared hinge mechanism  6  (therefore a mechanism which positively controls the rotation of the backrest) situated on one side of the seat. A first embodiment of this is illustrated in  FIGS. 2-6 ,  8 , and  9 . Alternatively, the hinge mechanism  6  can be driven by a motor or other means instead of the control button. This hinge mechanism  6  can be associated with an additional hinge mechanism  6 ′ which can be situated on the other side of the seat and which will be described below. 
     The hinge mechanism  6  comprises (see  FIGS. 2-6 ):
         a first frame  7  comprising a first disk-shaped metal end-plate  7   a  extending in a plane perpendicular to the axis Y 1  and which, in the example shown, may be integrally attached to the frame of the seat bottom  3 ,   a second frame  8  formed by a second disk-shaped metal end-plate parallel to the first end-plate  7   a , said second end-plate  8  being fixed for example to the frame of the backrest  2  (particularly by soldering or another method) and being held against the first end-plate by any known available means, for example by means of a metal locking ring  9  crimped onto said second frame and surrounding the first frame  7  (alternatively, the locking ring  9  can be replaced with a flat ring soldered onto the second frame  8  and surrounding the first frame  7 ),   a hypocycloidal gear  10  linking the first and second frames  7 ,  8  (see  FIG. 6 ),   and a control member  11 , also called a control shaft, which controls the hypocycloidal gear  10 .       

     The control member  11 , clearly visible in  FIGS. 2-7 , can, for example, be a single molded part made of plastic or a light alloy. This input means  11  comprises a central shaft  12  extending longitudinally along a central axis Y 2  parallel to the above-mentioned axis Y 1  but offset relative to this axis Y 1 . 
     The interior of the central shaft  12  may possibly be pierced with an opening  13  that is square-shaped (or ribbed or another shape). The utility of this opening will be seen below. 
     The end of the central shaft  12  opposite the second end-plate  8  extends radially outwards in a collar  14  parallel to the end-plates  7   a ,  8 . The internal face of the collar  14  extends towards the hypocycloidal gear  10  by at least one stop element  15 , and in this example by two stop elements  15  which are pins parallel to the axis Y 2  and extending towards the second end-plate  8 . The utility of said stop element or elements will be seen below. 
     The central shaft  12  is cylindrical in shape and its revolution is centered around the axis Y 2  and pivots within a bearing which is an integral part of the second end-plate  8  and which is itself centered around the axis Y 2 . Here, this bearing is formed by a cylindrical passage  8   b  through the second end-plate  8  and through a collet  8   a  which is an integral part of this second end-plate. The collet  8   a  can be formed for example as a single part with the second end-plate  8  and it extends axially from second end-plate  8  towards the first end-plate  7 . 
     In this example, the hypocycloidal gear  10  is a single gear train (but it could also be a planetary hypocycloidal gear train) which for example comprises:
         a first circular gear teeth  7   b  centered around the axis Y 1 , with these gear teeth facing radially outwards and formed in the periphery of the end-plate  7   a  of the first frame,   a second circular gear teeth  8   c  formed in the inner face of the second frame  8  and facing radially inwards, said second gear teeth  8   c  being centered around the axis Y 2  and having an internal diameter greater than the external diameter of the first gear teeth  7   b,      and an eccentric cam  29 , for example of metal, perpendicular to the axis Y 1  and driven by the input device  11 ; this cam revolves around the collet  8   a  in a cylindrical housing  30   a  which is an integral part of the first frame  7  and passes through the end-plate  7   a , said housing  30   a  being centered around the axis Y 1 . In particular, the cylindrical housing  30   a  is formed by the smooth and cylindrical inner surface of a metal collet  30  which is rigidly fixed to the end-plate  7   a . A gusset (not shown) may possibly be soldered around the collet  30 , said gusset being fixed to the frame of the seat bottom  3 . As shown in  FIGS. 3-7 , the collet  30  is integrally formed with the first frame as a single part.       

     A ring  31  acting as a bearing can be radially interposed when necessary between the eccentric cam  29  and the housing  30   a , said ring being press-fitted in place inside the housing  30   a.    
     The control member  11  is rotationally linked to the eccentric cam  29 . The rotation of the control member  11  around the second axis Y 2  thus rotationally drives the camshaft  29  around the second axis Y 2 , causing relative rotation between the first and second frames  7 ,  8 . 
     The cam  29  can be formed of a single part, but in the case considered here, it is made (see  FIGS. 4-6 ) of two wedge-shaped metal half-cams  29   a ,  29   b , each having a radial thickness which increases in the direction of the other half cam. The half-cams  29   a ,  29   b  can be relatively rotated between a position of minimum eccentricity (position in which they are closest together) and a position of maximum eccentricity (position in which they are furthest apart). 
     The half-cams  29   a ,  29   b  are elastically forced towards their position of maximum eccentricity by a spring  35 , for example a compression spring placed between the two half-cams  29   a ,  29   b . In the rest position of the hinge mechanism, the half-cams  29   a ,  29   b  serve to eliminate the internal play in the hypocycloidal gear  10 . 
     The half-cams  29   a ,  29   b  could also be replaced by superimposed disk-shaped half-cams, also known to a person skilled in the art. 
     The hinge mechanism  6  is fitted with a braking module  16  which comprises, in addition to said control member  11 :
         an operating member  17  which, as will be explained below, is axially fixed to the control member  11  and is rotatably mounted on the control member  11  with lost motion, with a small play of a few degrees, said control button  6   a  being fixed to the operating member  17  by any known means (particularly by clip-on or similar means),   a metal friction ring  18  which is axially retained between the collar  14  of the control member  11  and a collar  17   a  of the operating member  17 , said friction ring  18  being press-fitted in place inside the internal surface  30   a  of the collet  30  in order to become an integral part of said collet  30 , and said friction ring  18  delimiting an internal cylindrical friction surface  18   a  centered around the first axis Y 1 , this friction surface  18   a  extending axially between an internal shoulder  19  formed by the friction ring  18  and an end opening towards the operating member  17 ,   and a brake coil spring  20  which comprises a winding  21  and first and second terminating arms  22 ,  23  extending radially inwards, said winding  21  being centered around the first axis Y 1  and exerting friction against the friction surface  18   a  of the friction ring  18 , said winding  21  extending in a first angular direction  39  from the first terminating arm  22  to the second terminating arm  23 .       

     The control member  11  comprises retaining lugs  24 , for example three in number, which are arranged around the first axis Y 1  at a diameter which is less than the diameter of the collar  14 . These lugs  24  extend axially from said collar, away from the shaft  12 , each terminating in a free end having a hook  25  projecting radially outwards. 
     The lugs  24  and hooks  25  of the control member  11  are able to be clipped, with backlash, into indentations  26  in a central opening  27  arranged in a collar  17   a  of the operating member  17 . 
     The central opening  27  in the operating member  17  can be extended axially towards the control member  11  by a substantially annular wall  27   a  comprising crenellations  28  projecting radially outwards and delimiting said indentations  26 . 
     One of these crenellations  28  is arranged between the two terminating arms  22 ,  23  of the brake coil spring  20 , both lateral faces of this crenellation  28  forming unlocking stop elements  28   a ,  28   b  which are respectively positioned next to the second terminating arm  23  and the first terminating arm  22  of the brake coil spring (see  FIG. 9 ). 
     The collar  14  of the control member  11  also comprises an annular wall  32  which extends axially towards the operating member  17  and which comprises the first and second locking stop elements  33 ,  34  projecting axially towards the operating member  17  and radially outwards relative to the annular wall  32 , these first and second locking stop elements  33 ,  34  respectively bracketing the first and second terminating arms  22 ,  23  of the friction coil spring  20 , as can be seen more clearly in  FIG. 9 . 
     Finally, as shown in  FIG. 6 , the control member  11  of the hinge mechanism  6  is rigidly fixed to a rigid connecting rod  36  which is fitted into the opening  13  inside the shaft  12 , the end opposite the connecting rod  36  being fitted into the opening  13  inside the shaft  12  of the additional hinge mechanism  6 ′ situated on the other side of the seat. This additional hinge mechanism  6 ′, visible in  FIGS. 6 and 7 , is similar to the hinge mechanism  6  described above, although it does not include a braking module  16 . The control member  11  of the additional hinge mechanism  6 ′ is identical to the control member  11  of the hinge mechanism  6  at least in its portion facing the second frame  8 , but the collar  14  of the additional hinge mechanism  6 ′ does not have lugs  24  or an annular wall  32  opposite the second frame  8  (although the control member  11  of the additional hinge mechanism  6 ′ could be completely identical to that of the hinge mechanism  6 ). 
     One will note from the above that the braking module  16  uses only one side of the seat while being incorporated with the pre-existing hinge mechanism: this braking module therefore reduces the cost and weight of the seat, while providing a compact hinge mechanism. 
     In addition, the braking module  16  is in the form of an independent package which can be manufactured and stored separately from the rest of hinge mechanism  6 : during the manufacture of hinge mechanisms  6  and  6 ′, this manufacturing can be standardized in the production and assembly of the first and second frames  7 ,  8 , the locking ring  9 , and the cam  29 , until the installation of either the braking module  16  portion of the hinge mechanism  6 , or the control member  11  of the additional hinge mechanism  6 ′. 
     The hinge mechanism which has just been described functions as follows. 
     In the absence of activation of the operating member  17  by the control button  6   a , the brake spring  20  blocks the connecting rod  36  and the control devices  11  of both hinge mechanisms  6 ,  6 ′ by rubbing against the friction surface  18   a . If the control member  11  of one of hinge mechanisms  6 ,  6 ′ is subjected to torque in the first angular direction  39  due to external force applied to the backrest, the first locking stop element  33  acts on the first terminating arm  22  of the brake spring  20  in a direction which tends to increase the diameter of said spring, reinforcing the stopping action of this spring. The same is true for torque in the second angular direction  40  opposite the first direction, as in this case it is the second locking stop element  34  which acts on the second terminal arm  23  of the brake spring  20  in a direction which tends to increase the diameter of said spring. 
     When a user activates the control member  11  by using said button  6   a , in the first angular direction  39 , the first unlocking stop element  28   a  acts on the second terminating arm  23  of the brake spring  20  in a direction tending to decrease the diameter of said spring, which eliminates the stopping action of the brake spring and allows the operating member  17  to drive the control member  11  of both hinge mechanisms  6 ,  6 ′. One of the stop elements  15  of each control member  11  then exerts angular pressure against the narrow end of one of the half-cams  29   a ,  29   b , turning the cam  29  within the housing  30   a  of the collet, driving the gear  10 , such that the second frame  8  turns with the backrest  2  relative to the first frame  7  and to the seat bottom  3 . The operation is the same, but with the appropriate modifications, when a user activates the control member  11  by means of said button  6   a , in the second angular direction  40  (then it is the second unlocking stop element  28   b  which acts on the first terminating arm  22  of the brake spring).