Abstract:
A latch assembly for maintaining a seat back in upright position responsive to inertial loads. Support plates include hinged upwardly extending arms defining a seat back. A latch gear includes a first plurality of exteriorly arrayed teeth. A first cam operates a second pivotal cam so that, upon rotation, the second cam rotates in an opposite direction to move into and out of contact with a pawl. The pawl is pivotally and translatably secured to the support plates and includes additional teeth arrayed opposite to the latch gear teeth and an extending end with an upwardly/arcuate shape. A wedge block defines first and second shoulder supports. In operation, the pawl engages the first support surface of the block. In response to inertial loads, the pawl shifts radially to be engaged upon the second support surface, the pawl teeth being forcibly interengaged with the latch gear teeth.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. application Ser. No. 09/758,780, filed Jan. 11, 2001, for a Seat Integrated Latch Recliner Assembly with Inertial Locking Mechanism. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to seat integrated recliner latch assemblies. More particularly, the present invention is directed to a further improved recliner latch assembly incorporating a radially shiftable and yielding pawl, incorporating a deformable and substantially “peanut shaped” configuration, and within which is mounted a solid rivet, in combination with a fixedly positioned wedge block for creating an upward directing force on the pawl to maintain a toothed engagement with an upwardly extending and rotatably mounted seatback. 
     2. Description of the Prior Art 
     The prior art is well documented with examples of vehicle seat recliner mechanisms and, in particular, those which employ some form of inertial locking or restraining mechanism responsive to a determined force exertion and for the purpose of maintaining the seat back in an upright locked position. U.S. Pat. No. 5,163,735, issued to Aljundi, discloses an inertia latch for a vehicle seat backrest which includes a wheel having a pinion gear formed thereon and which engages sector plate teeth of a backrest bracket portion. As the backrest is shifted on rapid deceleration, the wheel rapidly drives a locking tooth into engagement with a locking pawl at the lower end of the inertia pendulum. The inertia pendulum is rotated upon application of an inertial load into an interlocking relationship with the locking tooth. A tilt control pinion gear engages a tilt sector plate to adjust the orientation of the seat back relative to the seat bottom. 
     U.S. Pat. No. 4,082,353, issued to Hollowell, teaches another variation of an inertia-responsive vehicle seat back latch mechanism for a vehicle seat assembly and including a seat back pivotally supported for forwardly tilting movement. The latch mechanism includes a seat back stud movable with the seat back, a locking pawl pivotally attached to the seat cushion support which is adapted to engage the seat back stud, and a latching pawl pivotally attached to the seat cushion support for preventing rotation of the locking pawl. The locking pawl is disposed to engage the seat back stud, but is cammable free of the seat back stud thereby allowing forward tilting of the seat back. During a vehicle deceleration greater than a predetermined value, the latching pawl prevents rotation of the locking pawl by engaging the locking pawl with the seat back and preventing forward tilting of the seat back. 
     Additional examples of vehicle seat back inertial locking devices are illustrated by U.S. Pat. No. 5,460,429, issued to Whalen, and U.S. Pat. No. 4,225,177, issued to Klutting. U.S. Pat. No. 5,328,241, issued to Haider, teaches a recliner for a vehicle seat assembly in which the locking pawl of the recliner is formed with teeth configured to resist damage when the seat back is rotated to a forward dump position. The pawl teeth are disclosed as being progressively longer, from the end of the pawl inward, over a selected number of teeth and so that the teeth resist bending deformation caused by impact with the latch gear end face. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention is a novel seat integrated restraint latch assembly with built-in inertial locking mechanism for maintaining a seat back of the seat in an upright position responsive to an experienced inertial load (also referenced as a “crash load”). Applicant further believes the design of the instant invention to set a new industry standard of load capability for a belted seat back latch/recliner mechanism. 
     The seat includes a frame constructed of a seat bottom and an upwardly extending and pivotally secured seat back. One or more pairs of spaced apart support plates are fixedly secured to the seat bottom and define a portion of the seat assembly. 
     The seat back is further defined in part by an extending arm pivotally connected to the support plates. The extending arm is preferably reinforced proximate the hinged and pivotal connection and so that, upon experiencing the inertial load, engages against an extending flange of one or both of the support plates and to prevent the arm from bending. A spring biased latch gear is mounted to the arm at the hinged connection and includes an exterior facing surface defied, in part, by a first plurality of teeth. 
     A first cam is actuated by a lever projecting from one facing side of a selected support plate of the seat frame. The first cam is pivotally secured between the support plates at a first specified location and is spring biased in a selected rotation direction. A second cam is likewise pivotally secured between the support plates at a second location. The first and second cams are configured with associated and matingly engaging, spaced apart finger portions such that, upon actuation and rotation of the first cam in a given direction, the second cam is influenced to rotate in an opposite direction. 
     A pawl is pivotally secured to the support bracket at a third location and is engageable by the second cam during normal operation. A solid pin extends through substantially “peanut shaped” apertures defined in the plates and the pawl disposed therebetween. The pawl further includes a second plurality of teeth arrayed in opposing fashion relative to the first plurality of teeth of the latch gear and an extending end configuration further defined by an upwardly and arcuately extending surface. 
     A wedge block is fixedly secured between the support plates at a fourth location. The wedge block includes, in the preferred variant, first and second shoulder support shoulder support surfaces which are configured in a stepped arrangement in opposing fashion to the extending end configuration of the pawl. The extending end configuration of the pawl is arrayed in slightly spaced and proximate fashion relative to the step in the wedge block, as defined by the support surfaces upon being rotated from a first latched position to a second disengaged position, and at which point the seat back may be rotationally readjusted relative to the support plates of the seat bottom. 
     The substantially “peanut shaped” apertures defined in the spaced apart support plates further include a first substantially circular shaped section and a second substantially circular shaped section communicating with the first circular section by a narrowed boundary disposed therebetween. The second circular shaped section is, in the preferred embodiment, substantially smaller in dimension than the first circular section and so that, upon inertial shifting of the pawl, the solid rivet tends to intentionally deform the support plates as it forces its way past the narrowed boundary and into the smaller dimensioned and second substantially circular shaped section and to thereby prevent any undesirable rebounding/backwards motion of the seat resulting from recoil forces following the initial forward impact. Also, the provision of a solid pin (or rivet), and as opposed to one that it hollowed internally, prevents shearing of the pin and resulting loss of integrity of the seatback in the crash position. 
     At this point, the extending end configuration engages upon the second and succeeding shoulder support surface and the second arrayed plurality of teeth of pawl are forcibly pressed into inter-engaging contact against the first plurality of teeth of the latch gear. Additional upward engagement against the pawl is further contributed by at least the second cam in the deformed and inertial loaded position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which: 
     FIG. 1 is an elevational view of the components of the seat frame within which the present latch assembly is incorporated, the seat frame including the pair of spaced apart support plates defining part of the seat bottom and the upwardly extending and rotatably associated arm forming a portion of the vehicle seat back; 
     FIG. 2 is a first plan view of the seatback arm latch gear, first and second cams, laterally shiftable pawl and fixed wedge block mounted in sandwiched fashion between the support plates and illustrated in a first latched and maximum reclined position; 
     FIG. 3 is a second plan view illustrating the seatback in a further and forwardly rotated and latched position; 
     FIG. 4 is a third plan view illustrating the pawl, by virtue of the first and second cams, being actuated to a disengaged position relative to the latch gear; and 
     FIG. 5 is fourth plan view illustrating the pawl in a laterally shifted position in response to a deformed and inertial loaded position and in which an extending end configuration of the pawl is seated upon the stepped shoulder support surface of the wedge block and so that an arrayed plurality teeth of the pawl are forcibly inter-engaged with an arrayed plurality of teeth of the latch gear to immovably restrain the arm. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference now to FIG. 1, a portion of a vehicle frame is illustrated at  10  and which incorporates an improved and inertial locking latch assembly according to the present invention. As previously described, the latch assembly according to the present invention also provides an additional factor of safety in that its construction prevents reverse/rebounding actuation of a seatback following the experience of an inertial collision force. 
     The frame  10  includes, in the preferred embodiment, a lower support bracket defined by a pair of generally planar shaped and supporting plates  12  and  14 . The support plates  12  and  14  are each preferably constructed of a sturdy, yet deformable steel material, and are preferably separated a spaced distance from one another by one or more spacer elements such as rivets  16 . 
     It is however further understood that a suitable support plate or bracket can be configured in other shapes without departing from the scope of the invention and it also envisioned that, rather than a pair of spaced apart plates  12  and  14 , a single appropriately configured plate can be utilized with the latching assembly according to the present invention and which will be subsequently described. It is further envisioned that the support plates  12  and  14  (and associated latching assembly) can be provided on a single side of a vehicle seat; however, and for larger 60/40 rear seat constructions (and such as is commonly used for second and third row seats in sport utility vehicles) a pair of support plates/latching assemblies may be provided on both sides of the seat. 
     Additionally, and while not illustrated, it is understood that the support plates may further be defined by an appropriate extending flange edge to provide an added measure of reinforcement against twisting forces of the seatback. Although not further shown, the support plates  12  and  14  are also understood to define a part of a conventional seat bottom of the seat frame and may also be secured to a floor of the vehicle interior, such as with the use of rivets, collar spacers and/or bolt fasteners (not shown) engaged through apertures  18  arranged in aligning fashion through selected and spaced apart plates  12  and  14 . 
     Referring again to FIG. 1, an additional plurality of aligning apertures are defined within the spaced apart support plates  12  and  14  and at selected locations. Specifically, aligning and spaced apart pairs of apertures  20 ,  22 ,  24 ,  26  (corresponding with rivet  16 ),  28  (corresponding with additional rivet  16 ),  30  and  32  are indicated. It is further understood that each pair of aligning apertures may further be defined by a projecting collared portion extending between the spaced apart plates  12  and  14  and the purpose for the arrangement and placement of the additional plurality of apertures will be further described below. 
     An upwardly extending arm  34  is provided, constructed of an appropriate grade steel or like material, and hingedly/pivotally connected in sandwiching fashion between the support plates  12  and  14 , such as through the use of a mounting collar of fastener (not shown) located at the lower end of the arm  34 . The arm  34  is reinforced by first  36  and second  38  projecting and axially extending edges which terminate in a conjoined edge (see as best illustrated at  40 ) projecting around the hinged connection and which, upon experiencing an inertial load, engages against a flange edge of one of the support plates  12  and  14  to prevent the arm  34  from bending. 
     Referring to FIGS. 2,  3  and  4  in succession, a latch gear  42  is illustrated which is secured to the arm  34  at the hinged connection and such as by pins, mounting fasteners or the like (not shown). The latch gear  42  includes a substantially rounded exterior surface and which is defined, over a selected range, by a selected plurality of teeth  44 . 
     A coil spring, illustrated at  46  in FIG. 1, spring biases the latch gear  42  (and overall seatback arm  34 ) in a given rotational direction, such as a counterclockwise direction as evidenced by directional arrow  48  in FIG.  1  and throughout the drawing figures. The spring  46  surrounds the pivotal mounting location of the latch gear  42 , and in one preferred embodiment is located on the outwardly facing side of the first (or outer) support plate  12 . An outermost spiraled and coiled end (or tang)  50  of the spring  46  is illustrated in FIG. 1 engaging in abutting fashion against a tabbed portion  52  extending from the support plate  12  and which influences the seat back  34  to pivot in a forward direction. 
     Having described in sufficient detail the aspects of the seat frame and seat back components, discussion will now be had as to the construction of the latch assembly according to the present invention. Specifically, a first cam  54  (refer to selected views FIGS. 2 and 4) is mounted over collared portion or like pin fastener or rivet associated with the pair of apertures  20  in the first  12  and second  14  plates and preferably in sandwiched fashion between the plates. The first cam  54  is further spring biased (by coil spring  56  illustrated in phantom in FIG.  2  and tabbed against phantom illustrated aperture  58  in plate  12 ) in a counterclockwise direction. In the preferred embodiment, the first cam  54  forms a portion of a rotatably actuated lever (not illustrated) projecting from the side of the seat bottom and by which the user may actuated the latch assembly in normal operation. 
     A second cam  60  is mounted over the collared portion or other suitable fastener extending between aligned apertures  22  in the plates  12  and  14  and in similar fashion as the first cam  54  and so that the first cam  54  and second cam  60  rotatably engage one another. This is accomplished by an exterior configuration of the first cam  54  being defined, in part, by a first plurality of spaced apart fingers  62  which meshingly and matingly engaged a corresponding second plurality of spaced apart fingers  64  arranged at a specified external configuration location of the second cam  60  and so that, upon rotation of the first cam  54  in such as a clockwise direction, the second cam  60  is engageably rotated in a reverse and counterclockwise fashion. The external configuration of the second cam  60  is further defined by a first projecting location  66  and a second projecting location  68 , the purpose for which will be subsequently described. 
     A pawl  70  is provided as a substantially elongated member and which is mounted by a solid rivet  72  extending through the pawl  70  and engaging through each of the aligning apertures generally illustrated at  24  for the first  12  and second  14  support plates and so as to mount the pawl  70  in likewise sandwiching fashion between the support plates  12  and  14  and in both pivotal and translational fashion. Each of the apertures  24  is further constructed as a substantially “peanut shaped” aperture as best illustrated in FIG. 1 and a more detailed description will be had below, and with further reference to the crash position of the latch assembly of FIG. 4, of the interacting of the peanut shaped apertures  24  and the solid extending rivet  72 . 
     The elongate extending body of the pawl  70  includes a substantially rounded end  74  which it is rotatably engaged to the solid rivet  72 . Additional characteristics of the pawl  70  include a uniquely configured projections  76  and  78  and alternating recess  80  defined in a downwardly facing surface and which precedes a substantially arcuate extending surface  82  terminating in an extending end configuration. The end configuration of the pawl  70  is further defined by a stepped support surfaces  84  and  86 . Defined in an opposite and upwardly facing surface of the pawl  70 , and along a selected range, is a plurality of teeth  88 . 
     A wedge block  90  is fixedly secured in sandwiching fashion between the support plates  12  and  14  at the location defined by the rivets  16  extending through the apertures  26  and  28 , as well as additional collared projections (see in particular FIG. 2,  3  or  5 ), spacers or like fasteners associated with corresponding spaced apart apertures  30  and  32 . Again, mounting pins or the like (not shown) may be employed to securely mount the wedge block  90  in place and it is understood that the wedge block  90  is fixedly secured between the plates  12  and  14 . 
     The wedge block  90  is arranged in an opposing fashion relative to the extending end configuration (stepped surfaces  84  and  86 ) of the pawl  70  and the wedge block  90  likewise includes a first shoulder support surface  92  and a second shoulder support surface  94  stepped upwardly from the first support surface  88 . The wedge block  90  also includes an extending and abutment portion  96  which is angled in an upward and forward direction towards the seatback arm  34  and which terminates in a rounded edge  98 . 
     As best illustrated in FIG. 1, a rear location  100  of the seatback  34  abuts the rounded upper edge  98  of the wedge block  90  and to prevent the seatback  34  from being reclined beyond a certain point. This is especially significant when considering the application of the seat reclining mechanisms in second and third row vehicle seats and one preferred variant contemplates a maximum of approximately 16° incline of the seatback relative to a vertical axis. It is however understood that the degree of inclination permitted of the seatback  34  may be adjusted and/or the extending portion  96  deleted from the wedge block  90  without departing from the scope of the invention. 
     Referring again to FIG. 2, the configuration of the downwardly facing surface of the pawl  70  (and in particular a succeeding projection location  102   78 ) is illustrated seated upon second projecting location  68  of the second cam  60  and so that the plurality of upwardly facing teeth  88  are maintained in the specified and interengaging relationship with the opposing plurality of teeth  44  associated with the latch gear  42 . Referring further to FIG. 3, a succeeding latched position of the seatback  34  is again shown and in which the first projecting location  66  of the second cam  60  is seated within associated recess  80  in the underside of the pawl  70 . The first cam  54  is deleted from the illustrations of FIGS. 3 and 5 for purposes of clarity of illustration, however it is understood that the first cam  54  may be rotated by the user (through engagement of the corresponding handle) and in order to actuated the cams  54 ,  60  and pawl  70  in normal operation of the latch assembly. 
     Upon actuating the first  54  and second  60  cams in the manner illustrated by FIG. 4, the first  66  and second  68  projecting locations of the second cam  62  are rotated in the counterclockwise direction relative to the pawl  70 , thus unseating from the recess  80  in the downwardly facing surface and in which the first projecting location  66  engages configured projection  76  of the pawl and the second projecting location  68  likewise engages against projection  78 . This in turn causes the upwardly facing teeth  88  of the pawl  70  to drop out of engagement with the teeth  44  of the latch gear  42 . Concurrently, the arcuately extending surface  82  (and proximate the end configuration  84  and  86  of the pawl  70 ) is illustrated in slightly spaced apart and proximate fashion relative to the first  92  of the stepped shoulders associated with the wedge block  90 . 
     Referring now to FIG. 5, an explanation will now be provided as to how, upon the occurrence of an inertial load (or which is otherwise termed a “crash load”), the latch assembly of the present invention provides a securely seating or wedging support of the teeth  88  of the pawl  70  against the teeth  44  of the opposing latch gear  42 . Specifically, and referring again to FIG. 1, the aligning and generally indicated, peanut shaped apertures  24  are again illustrated in both the support plates  12  and  14 . As also previously described, the solid rivet  72  extends through an aperture (not shown) through the pawl  70  at the location of the rounded end  74 . Alternatively, the rivet  72  may be fixedly secured in oppositely extending fashion to both sides of the pawl  70  without departing from the scope of the invention. 
     The peanut shaped apertures  24  in the plates  12  and  14 , again best illustrated in FIG.  1  through the first such plate  12 , further includes a first substantially circular shaped section  104  and a second substantially circular shaped section  106  communicating with the first circular section by a narrowed boundary  108  disposed therebetween. The pin  72  remains seated in the first  104 , and larger, circular shaped section and so that the pawl  70  may operate in its normally pivoting manner as illustrated throughout FIGS. 2-4. 
     The second circular section  106 , as clearly illustrated, is substantially smaller in dimension than the first circular section  104  such that, upon the occurrence of the inertial load, the solid pin or rivet  72  radially shifts across the narrowed boundary  108  to a position in which it substantially lies within the second circular section  106  (see again FIG.  5 ). At this point, the pawl  70  shifts in substantially translational fashion to the right and so that its succeeding stepped surface  86  is wedged in supporting fashion against the boundary between the stepped locations  92  and  94  of the opposing wedge block surface. Concurrently, projections  66  and  68  of the second cam  60  abuttingly engage the underside of the pawl  70  at the same locations previously identified in FIG.  3  and corresponding to the second normally latched position. 
     As discussed previously, an advantage of the present design includes the ability of the support plates  12  and  14  (as opposed to the pawl  70  and/or rivet  72 ) to deform in response to the solid rivet  72  forcibly shifting across the narrowed boundary  108  and to the second and smaller circular section  106 . Deformation of the plates  12  and  14  is preferable to deformation and/or shearing of the pawl  70  or rivet  72  in that, upon occurrence of the latter, the mating teeth of the pawl  88  would disengage from those of the latch gear  42 , with the result being the seatback  34  being free to rotate in a recoiling and reverse fashion in response to an initial crash load. 
     Having described our invention, it is apparent that it discloses a novel latch assembly a seat reclining mechanism and which is a novel improvement over the prior art in that it further provides an increased degree of holding support between the pawl and latch gear of the seat back and prevents accidental shearing of the pin/rivet  72  and/or release of the seatback  34  in a reverse/recoiling direction in response to a crash load. Additional preferred embodiments of the present latch assembly will become apparent to those skilled in the art and without deviating from the scope of the appended claims. In particular, it is envisioned that the latch assembly could be reconfigured to operate with a single cam element in place of the two cams disclosed in the preferred embodiment. Further, the shaping of the pawl, wedge block and range and positioning of the interengaging teeth can also be modified within the scope of the invention and it is again envisioned that the latch assembly could be configured for use with any of a single support plate, a pair of spaced apart support plates located on a given side of a vehicle seat. It is again envisioned that multiple latch assemblies could be configured for use with individual pairs of support plates located on either side of a vehicle seat or even at an intermediated location of a larger sized seat.