Abstract:
A compact disc recliner mechanism for reducing chucking includes a drum adapted to be fixed to a quadrant for rotation relative to a plate and three locking members having locking surfaces for locking said quadrant relative said plate. At least one locking member moves relative the quadrant from a first position engaging the drum to a second position disengaging the drum. At least one other locking member is fixed relative the plate and movable from a first position engaging the drum to a second position disengaging the drum. A cam moves the first, second, and third locking members from a first position engaging the drum to a second position disengaging the drum. A recliner assembly for use with a seat having a seat back and a seat base includes the compact disc recliner mechanism according to the invention.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a recliner mechanism and, more particularly, to a compact disc recliner mechanism for reducing undesirable movement when the mechanism is locked. 
     Rotary recliner mechanisms generally consist of a first rotary member having a plurality of teeth and a second rotary member including one or more pawls adapted to lockingly engage the teeth to couple the rotary members to one another. Typically, one rotary member is mounted to a quadrant for attachment to a seat back and the second rotary member is mounted to a base plate for attachment to a seat base. The rotary recliner mechanisms are operable to lock the rotary member connected to the seat back to restrict its rotation, or to release the rotary member connected to the seat back to allow it to rotate and to enable the seat back to recline. The mechanism is selectively locked or released by manipulating the one or more pawls, which are mounted for rotation between an engaged position where the teeth of the pawl and the teeth of the rotary member connected to the seat base mesh, and a disengaged position where the pawl retracts and no longer meshes with the teeth of the rotary member connected to the seat base. Locking rotary recliner mechanisms also may include a device, such as a spring, for releasably urging the pawl from the disengaged to the engaged position so that the default position for the mechanism is a locked condition. Further, the rotary recliner typically includes an activating mechanism that moves the pawl from the engaged position to the disengaged position. 
     In reclining seats, the seat back functions as an extremely long lever arm against which various forces are applied. The locking rotary recliner mechanism in a vehicle seat is relatively small compared to the length of the reclining seat back, and vehicle vibration or movement of an occupant may impose various forces upon that lever during use. These forces impose a large moment about the rotary member connected to the seat back when applied along such a lengthy lever arm. If the forces are sufficient, or the rotary recliner mechanism is poorly designed, these forces can overcome the capability of the rotary recliner mechanism to anchor the seat back. In addition, any imperfection in the components of the pivot mechanisms, such as play or backlash between the engaging teeth or tolerances between the mechanism components, may allow the rotary member connected to the seat back to move a miniscule amount even when the mechanism is locked. These small movements are magnified by the length of the lever arm and become noticeable at the upper end of the seat. For example, the seat back of an unoccupied seat may tend to oscillate when the vehicle encounters rough road conditions. Because the motion of the seat back is amplified by the length of the seat back frame, the vibration of the seat back can be relatively large. This magnified play in locking pivot mechanisms has been termed “chucking” and refers to any imperfections or play in the mechanism components that allow movement of the rotary member and attached seat back while the mechanism is in a locked condition. 
     One technique employed to reduce chucking is to form the components of the pivot mechanism with exceedingly close tolerances. This technique reduces play in the mechanism, and thus reduces chucking, but manufacturing to such close tolerance is expensive. Further, close tolerances may bind the components of the system and prevent smooth operation. 
     SUMMARY OF THE INVENTION 
     It is therefore desirable to construct a locking recliner mechanism that is relatively small and simple, operates smoothly without binding, and does not require excessively close tolerances, yet is capable of locking the seat back in a fixed position while inhibiting play or excursions. 
     Accordingly, the compact disc recliner mechanism of the present invention provides a novel configuration to reduce chucking. The present invention provides a novel pawl and pawl carrier configuration with a biasing force applied on a cam urging at least one pawl and the pawl carrier into contact with a drum at three points. These three locking relationships enable firm engagement of the disc recliner mechanism and reduce chucking. 
     These and other advantages and features will become apparent from the following description and claims in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of a locking compact disc recliner mechanism according to the invention secured between a base plate adapted to be fixed to a seat base and a quadrant adapted to be fixed to a seat back; 
     FIG. 2 is an exploded perspective view of the locking compact disc recliner mechanism of FIG. 1; 
     FIG. 3 is a partially sectioned end view of the locking compact disc recliner mechanism of FIGS. 1 and 2 in the locked position; 
     FIG. 4 is a partially sectioned end view of the locking compact disc recliner mechanism of FIGS. 1 and 2 in the unlocked position; 
     FIG. 5 is a section view along lines  5 — 5  of FIG. 4; 
     FIG. 6 is an exploded perspective view of a locking compact disc recliner mechanism according to an alternative embodiment of the invention; 
     FIG. 7 is a partially sectioned end view of the locking compact disc recliner mechanism of FIG. 6 in the locked position; and 
     FIG. 8 is a partially sectioned end view of the locking compact disc recliner mechanism of FIGS. 6 and 7 in the unlocked position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention generally provides a compact disc recliner mechanism that may be used as a seat recliner to reduce play or chucking of a seat back when the mechanism is locked. Referring to the drawings, the disc recliner mechanism, in its locked mode, includes a biasing force applied on a cam urging three locking members, e.g., two pawls and one locking surface on a pawl carrier or one pawl and two locking surfaces on a pawl carrier, into contact with a drum for locking the seat back relative the seat base. The locking members are disengaged from the drum by overcoming the biasing force in the compact disc recliner mechanism&#39;s unlocked mode. The three locking members provide a strong and stable locking mechanism that operates smoothly and reduces chucking without binding or requiring excessively close tolerances. 
     More particularly, FIGS. 1-5 show a recliner assembly that includes a locking disc recliner mechanism  10  secured between a base plate  6  adapted to be fixed to a seat base  2  and a quadrant  8  adapted to be fixed to a seat back  4 . The locking disc recliner mechanism  10  includes a drum  12  adapted to be affixed to the quadrant  8 , a pawl carrier  14  adapted to be affixed to the base plate  6 , pawls  16 ,  18  for selectively locking the pawl carrier  14  relative the drum  12 , and a cam disc  20  for moving the pawls  16 ,  18 . The drum  12  and pawl carrier  14  are disposed generally coaxially about a shoulder  26  of a pivot axle  22  for rotation about the pivot axle  22 . The cam disc  20  is mounted on a keyed end  24  of the pivot axle  22  for fixed rotation with the pivot axle  22 , which can be actuated by an occupant-operable handle or lever (not shown). 
     A ring  32  is fixed to rotate with the drum  12  and together rotate with the quadrant  8  and the seat back  4 . The drum  12  includes a base  34  and a cylindrical wall  36 . The base  34  includes apertures  66  adapted to receive fasteners (not shown) for securing the drum  12  to the quadrant  8 . A central aperture  68  in the base  34  receives the pivot axle  22 , whereby the drum  12  is rotatable about the shoulder  26  of the pivot axle  22 . When the ring  32  is seated in the drum  12 , the outer diameter of the ring  32  abuts the inner diameter surface of a cylindrical drum wall  36 . Preferably, the cylindrical wall  36  includes a channel  82  formed in the inner diameter surface adjacent the outermost edge for seating a lock ring  80 , which retains the pawl carrier  14  and ring  32  within the drum  12 . More particularly, the ring  32  is positioned within the drum  12  such that the cylindrical wall  36  extends laterally beyond the seated ring  32 . After the ring  32  is seated in drum  30 , the pawl carrier  14  is disposed adjacent a surface  38  of the ring  32  and the lock ring  80  is disposed within the channel  82  to secure the assembly. The inner diameter surface of the ring  32  includes teeth  28  adapted for meshing engagement with the pawls  16 ,  18 . 
     The pawl carrier  14  includes an outer rim  54  surrounding a generally cylindrical central portion  58  having a pair of slots  42 , 44  containing pawls  16 ,  18 , respectively, as well as an arcuate slot  46  seating a cam retention spring  50 . The spring  50  biases the cam disc  20  to an engaged position wherein the pawls  16 ,  18  are placed into meshing engagement with the teeth  28  of the ring  32 . The cam disc  20  is movable by the operator against the bias of spring  50  to a disengaged position (FIG. 4) wherein pawls  16 ,  18  are moved away from the teeth  28  of the ring  32 . The pawl carrier  14  includes a central aperture  48  adapted to coaxially receive the pivot axle  22  for rotation thereabout. Like drum  12 , the pawl carrier  14  is disposed generally coaxially about the shoulder  26  of the pivot axle  22 . The central aperture  48  has a diameter slightly larger than the diameter of the shoulder  26 , whereby the pawl carrier  14  is able to move radially relative the pivot axle  22  for locking the pawl carrier  14  relative the drum  12 . Also, multiple mounting apertures  52  are located in the central portion  58  of the pawl carrier  14  to receive mounting pins  40  that support the cam disc  20  and secure the pawl carrier  14  to the base plate  6  (FIGS.  1  and  5 ). The outer rim  54  includes a peripheral surface  96  that is spaced apart from the inner diameter surface of the cylindrical drum wall  36  when the pawls  16 ,  18  disengage the teeth  28  of the ring  32  and engages the wall  36  of the drum  12  when the pawls  16 ,  18  engage the teeth  28  of the ring  32 . The outer diameter of the pawl carrier  14  is preferably approximately 0.5 millimeters smaller than the inner diameter of a drum  12  that is approximately 72 millimeters in diameter. 
     The pawls  16 ,  18  are generally block-like bodies having teeth  30  on one end thereof The pawls  16 ,  18  are slidably contained in the slots  42 , 44 , respectively, of the pawl carrier  14  to selectively engage the teeth  28  of the ring  32 . Further, each pawl  16 ,  18  includes a pin  60  extending in a direction generally transverse to the teeth  30  for engagement by the cam disc  20 , which moves the pawls  16 ,  18  between their engaged and disengaged positions (FIGS. 3 and 4, respectively). 
     The cam disc  20  is a generally tri-lobed plate including a keyed central aperture  70  adapted to receive the keyed end  24  of the pivot axle  22 . Thus, when the pivot axle  22  rotates, the keyed end  24  forces the cam disc  20  to rotate therewith. The cam disc  20  also includes a finger  62  transversely extending from the body thereof for engaging the spring  50 , which biases the cam disc  20  in a counter-clockwise direction (as shown in FIGS.  3  and  4 ). The cam disc  20  further includes cam slots  72 ,  74  for slidably receiving the pins  60  of pawls  16 ,  18 , respectively. More specifically, the cam slots  72 ,  74  include cam surfaces  94  defining the slots  72 ,  74  and abutting the pins  60 . Between the lobes of the cam disc  20  are edge surfaces  76  for abutting the pins  40  mounted in the apertures  52  of the pawl carrier  14 . The pins  40  include annular shoulders  56  (FIG. 2) to secure the cam disc  20  against axial movements relative the pawl carrier  14 , but permit limited rotation of the cam disc  20  relative to the pawl carrier  14 . The magnitude of the rotational movement is defined by the length of the edge surfaces  76  extending between the lobes. Thus, as the pins  40  ride the arcuate edge surfaces  76  upon rotation of the pivot axle  22 , the pins  60  of the pawls  16 ,  18  cam along the edges of cam slots  72 ,  74 , respectively, of the cam disc  20 . As the pins  60  move in the slots  72 ,  74 , the pawls  16 ,  18  slide radially within slots  42 ,  44  into and out of meshing engagement with teeth  28  of the ring  32 . 
     When assembled, the pawl carrier  14  seats in the drum  12  with its central portion  58  disposed generally coaxial with the ring  32  and its outer rim  54  seated on the surface  38  of the ring  32 . The cam retention spring  50  is disposed in the arcuate slot  46 , and the transverse finger  62  of the cam disc  20  extends into the arcuate slot  46  and in abutment with an end of the cam retention spring  50 . The spring  50  normally biases the cam disc  20  to its engaged position forcing the pawls  16 ,  18  into engagement with the teeth  28  of the ring  32 , as shown in FIG.  3 . The cam disc  20  is seated in the central portion  58  and within the inner diameter of the rim  54  of the pawl carrier  14 , whereby the spring  50  is retained within the arcuate slot  46 . The annular shoulders  56  of the pins  40  retain the cam disc  20  in coaxial abutment with the central portion  58  of the pawl carrier  14 . The lock ring  80  is secured within the channel  82  of the drum  12  along the outermost edge of the cylindrical wall  36  such that the assembly of the cam disc  20 , the pawl carrier  14 , and the ring  32  are retained within the drum  12 . 
     In use, the disc recliner mechanism  10  is secured to both a seat back  4  and a seat base  2  through the quadrant  8  and base plate  6 , respectively. More specifically, apertures  66  in the base  34  of the drum  112  are adapted to receive fasteners for securing the drum  12  to the quadrant  8 . Similarly, apertures  78  disposed in the pins  40  for supporting the cam disc  20  are adapted to receive fasteners for mounting the pawl carrier  14  to the base plate  6 . Preferably, the fasteners are rivets  84 , as shown in FIG.  1 . The quadrant  8  is secured to the seat back  4  and the base plate  6  is secured to the seat base  2 . In this manner, the drum  12  is able to rotate relative the pawl carrier  14  when the seat back  4  is rotated relative the seat base  2  and the teeth  30  of the pawls  16 ,  18  are disengaged from the teeth  28  of the drum  12 . 
     As shown in FIG. 3, the cam retention spring  50  biases the cam disc  20  into a position that forces the teeth  30  of the pawls  16 ,  18  into engagement with the teeth  28  of the drum  12 . An operator must rotate the pivot axle  22  and the cam disc  20  against the bias of the cam retention spring  50  to disengage the pawls  16 ,  18  from the teeth  28  of the ring  30 , as shown in FIG.  4 . When the pawl carrier  14  is rotated, the pins  60  of pawls  16 ,  18  slide in cam slots  72 ,  74 , respectively. The cam slots  72 ,  74  are shaped to force the pins  60 , and thus the pawls  16 ,  18 , away from the ring  32  during counterclockwise rotation of the cam disc  20  against the bias of spring  50 . Upon sufficient counterclockwise rotation, the teeth  30  of pawls  16 ,  18  disengage the teeth  28  of the ring  32 , thereby allowing the seat back  4  to be rotatively adjusted relative the seat base  2 . Once disengaged, the drum  12  is able to rotate relative the pawl carrier  14 . 
     When the pawls  16 ,  18  are in meshing engagement with teeth  28  of the ring  32 , an edge  86  of the pawl carrier  14  generally opposite the disposition of the pawls  16 ,  18  is forced against an adjacent portion of the cylindrical wall  36  such that the peripheral surface  96  engages the cylindrical wall  36 . The use of three contact points, i.e., the teeth  30  of pawls  16 ,  18 , and the peripheral surface  96  of the pawl carrier  14 , against the cylindrical wall  36  creates a very strong and stable locking mechanism. Further, because only two of the contact points are movable, i.e., pawls  16 ,  18 , the play in the locking disc recliner mechanism  10  is minimized. Thus, the inclusion of a fixed contact point—surface  96  of the pawl carrier  14 —provides reduction in play or chucking in a relatively small and simple locking mechanism that operates smoothly without binding and does not require excessively close tolerances. 
     An alternative embodiment of the invention is shown in FIGS. 1,  6 - 8  as disc recliner mechanism  110 . Like disc recliner mechanism  10 , the disc recliner mechanism  110  is secured between the base plate  6  adapted to be affixed to the seat base  2  and the quadrant  8  adapted to be affixed to the seat back  4 . The disc recliner mechanism  110  includes a drum  112  adapted to be affixed to the quadrant  8 , a pawl carrier  114  adapted to be affixed to the base plate  6 , a pawl  116  for selectively locking the pawl carrier  114  relative the drum  112 , and a cam disc  120  for moving the pawl  116 . The drum  112  and pawl carrier  114  are disposed generally coaxially about the shoulder  26  of the pivot axle  22 . The cam disc  120  is mounted on the keyed end  24  of the pivot axle  22  for fixed rotation with the pivot axle  22 , which can be actuated by an occupant-operable handle or lever (not shown). 
     A ring  132  is fixed to rotate with the drum  112  and together rotate with the quadrant  8  and the seat back  4 . The drum  112  is similar to the drum  12  and includes a base  134  having apertures  166  for receiving fasteners (not shown) for securing the drum to the quadrant  8 . Similar to the prior embodiment, the ring  132  is seated in the drum  112  such that the outer diameter of the ring  132  abuts the inner diameter surface of a cylindrical drum wall  136  and a lock ring  180  seats in a channel  182  formed in the inner diameter surface to retain the pawl carrier  114  and ring  132  within the drum  112 . The ring  132  is positioned within the drum  112  such that the cylindrical wall  136  extends laterally beyond the seated ring  132 . After the ring  132  is seated in the drum  130 , the pawl carrier  114  is disposed adjacent a surface  138  of the ring  132  and the locked ring  80  is disposed within the channel  182  to secure the assembly. The inner diameter surface of the ring  132  includes teeth  128  adapted for meshing engagement with the pawl  116 . The pawl carrier  114  includes an outer rim  154  surrounding a generally cylindrical central portion  158  having a slot  142  adapted to contain the pawl  116 , as well as a pair of arcuate slots  144 ,  146  seating cam retention springs  150 . The springs  150  bias the cam disc  120  to an engaged position wherein the pawl  116  is placed into meshing engagement with the teeth  128  of the ring  132 . The cam disc  120  is moveable by the operator against the bias of the springs  150  to a disengaged position (FIG. 8) wherein the pawl  116  is moved away from the teeth  128  of the ring  132 . 
     Similar to the prior embodiment, the pawl carrier  114  includes a central aperture  148  adapted to coaxially receive the pivot axle  22  for rotation thereabout. The central aperture  148  has a diameter slightly larger than the diameter of the shoulder  26  of the pivot axle  22 , whereby the pawl carrier  114  is able to move radially relative the pivot axle  22  for locking the pawl carrier  114  relative the drum  112 . Multiple mounting apertures  152  are located in the central portion  158  of the pawl carrier  114  to receive mounting pins  40  that support the cam disc  120  and secure the pawl carrier  114  to the base plate  6  (FIG.  1 ). The outer rim  154  includes peripheral locking surfaces  196 ,  198  that are spaced apart from one another and the cam slot  142 . Preferably, the cam slot  142  and the peripheral locking surfaces  196 ,  198  are equidistantly spaced apart on the pawl carrier  114 . The locking surfaces  196 ,  198  are spaced apart from the inner diameter surface of the cylindrical drum wall  36  when the pawl  116  is disengaged from the teeth  128  of the ring  132  and engage the wall  36  of the drum  112  when the pawl  116  engages the teeth  128  of the ring  132 . Preferably the outer diameter of the pawl carrier  114  is approximately 0.5 millimeters smaller than the inner diameter of an approximately 72 millimeter diameter drum  112 . 
     The pawl  116  is a generally block-like body having teeth  130  on one end thereof and is slidably contained in the slot  142  of the pawl carrier  114  to selectively engage the teeth  128  of the ring  132 . The pawl  116  includes a pin  160  extending in a direction generally transverse to the teeth  130  for engagement by the cam disc  120 , which moves the pawl  116  between its engaged and disengaged positions (FIGS. 7 and 8, respectively). 
     The cam disc  120  is a generally tri-lobed plate including a keyed central aperture  170  adapted to receive the keyed end  24  of the pivot axle  22 . Thus, when the pivot axle  22  rotates, the keyed end  24  forces the cam disc  120  to rotate therewith. The cam disc  120  further includes a pair of spaced apart fingers  162  transversely extending from the body thereof for engaging the springs  150 , which bias the cam disc  120  in a clockwise direction (as shown in FIGS.  7  and  8 ). The cam disc  120  further includes a cam slot  172  for slidably receiving the pin  160  of the pawl  116 . The cam slot  172  includes a cam surface  194  defining the slot  172  and abutting the pin  160 . Between the lobes of the cam disc  120  are edge surfaces  176  for abutting the pins  40  mounted in the apertures  52  of the pawl carrier  114 . The annular shoulders  56  of the pins  40  secure the cam disc  120  against axial movements relative the pawl carrier  114 , but permit limited rotation of the cam disc  120  relative the pawl carrier  114 . The magnitude of the rotational movement is defined by the length of the edge surfaces  76  extending between the lobes. Thus, as the pins  40  ride the arcuate edge surfaces  176  upon rotation of the pivot axle  22 , the pins  160  of the pawl  116  cam along the edge of the cam slot  172  of the cam disc  120 . As the pin  160  moves in the slot  72 , the pawl  116  slides radially within the slot  142  in the pawl carrier  114  into and out of meshing engagement with the teeth  128  of the ring  132 . 
     When assembled, the pawl carrier  114  seats in the drum  112  with its central portion  158  disposed generally coaxial with the ring  132  in its outer rim  154  seated on the surface  138  of the ring  132 . The cam retention springs  150  are disposed in the arcuate slots  144 ,  146 , and the transverse fingers  162  of the cam disc  120  extend into the arcuate slots  144 ,  146  and in abutment with an end of each cam retention spring  150 . The springs  150  normally bias the cam disc  120  to its engaged position forcing the pawl  116  into engagement with the teeth  128  of the ring  132 , as shown in FIG.  7 . The cam disc  120  is seated in the central portion  158  and within the inner diameter of the rim  154  of the pawl carrier  114 , whereby the springs  150  are retained within their slots  144 ,  146 . The annular shoulders  56  of the pins  40  retain the cam disc  120  in coaxial abutment with the central portion  158  of the pawl carrier  114 . The lock ring  180  is secured within the channel  182  of the drum  112  along the outermost edge of the cylindrical wall  36  such that assembly of the cam disc  120 , the pawl carrier  114 , and the ring  132  are retained within the drum  112 . 
     In use, the disc recliner mechanism  110  is secured to both the seat back  4  and the seat base  2  through the quadrant  8  and base plate  6 , respectively, as shown in FIG.  1 . More specifically, apertures  166  and the base  134  of the drum  112  are adapted to receive fasteners for securing the drum  112  to the quadrant  8 . Similarly, apertures  78  disposed in the pins  40  for supporting the cam disc  120  are adapted to receive fasteners for mounting the pawl carrier  114  to the base plate  6 . Preferably, the fasteners are rivets  84 , as shown in FIG.  1 . The quadrant  8  is secured to the seat back  4  and the base plate  6  is secured to the base  2 . In this manner, the drum  112  is able to rotate relative the pawl carrier  114  when the seat back is rotated relative the seat base  2  and the teeth  130  of the pawl  116  are disengaged from the teeth  128  of the drum  112 . 
     As shown in FIG. 7, the cam retention springs  50  bias the cam disc  120  into a position that forces the teeth  130  of the pawl  116  into engagement with the teeth  128  of the drum  112 . An operator must rotate the pivot axle  22  and the cam disc  120  against the bias of the cam retention springs  150  to disengage the pawl  116  from the teeth  128  of the ring  30 , as shown in FIG.  8 . When the pawl carrier  114  is rotated, the pin  160  of the pawl  116  slides in the cam slot  72 , which is shaped to force the pin  160 , and thus the pawl  116 , away from the ring  132  during counterclockwise rotation of the cam disc  120  against the bias of the springs  150 . Upon sufficient counterclockwise rotation, the teeth  130  of the pawl  116  disengage the teeth  128  of the ring  132 , thereby allowing the seat back  4  to be rotatively adjusted relative the seat base  2 . Once disengaged, the drum  112  is able to rotate relative the pawl carrier  114 . 
     When the pawl  116  is in meshing engagement with the teeth  128  of the ring  132 , the locking surfaces  196 ,  198  extending radially from the periphery of the pawl carrier  154  are forced against the cylindrical wall  36 . Because the locking surfaces  196 ,  198  are preferably equidistantly spaced apart from each other and the pawl  116 , three contact points are made to hold the disc recliner mechanism  10  in position. The use of three contact points, i.e., the teeth  30  of the pawl  116  and the spaced apart peripheral locking surfaces  196 ,  198  of the pawl carrier  114 , against the cylindrical wall  36  creates a very strong and stable locking mechanism. Further, because only one of the contact points is moveable, i.e., pawl  116 , the play in the locking disc recliner mechanism is minimized. Thus, the inclusion of a pair of fixed contact points—the locking surfaces  196 ,  198  of the pawl carrier  114 —provide reduction in play or chucking in a relatively small and simple locking mechanism that operates smoothly without binding and does not require excessively close tolerances. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.