Abstract:
Signaling device indicates when a folding backrest of a vehicle seat is in an unlocked position, and includes an actuating knob axially guided in a housing and which is pushed into its locked position by a compression spring. A stop is provided to prevent the actuating knob from extending further outwardly of the housing in its locked position. Actuating knob activates a locking mechanism via a mechanical transmission mechanism thereby allowing the backrest to be unlocked by pressing the actuating knob into the housing. This eliminates the need for a separate indicator device, given that when the actuating knob extends outwardly of the housing, the user can readily tell that the backrest is in its unlocked position. To enhance the signaling effect, the signaling portion of the actuating knob can be painted red, for example.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of German Application No. 10 2004 045 988.6, filed Sep. 22, 2004, and which is incorporated herein by reference. 
   FIELD OF THE INVENTION 
   The invention relates to a device to indicate when a movable or folding backrest of a vehicle seat is not in a locked position. More particularly, the invention relates to a device to indicate when a folding backrest of a vehicle seat is in an unlocked position. 
   BACKGROUND OF THE INVENTION 
   Passenger cars with folding seats have represented the state of the art for many years. In several models the backrest is divided into sections so that certain segments or the entire backrest may be folded down. The arresting and securing of the backrest and/or portions thereof is facilitated by a locking mechanism, which can be released by use of an actuating knob connected to mechanical transmission means such as a cable, rod or lever. The backrest or a portion thereof can be folded forward and down to expand cargo area. The backrest can then be folded back to return the seat to passenger use. When returning the seat to passenger use, it can occur that the backrest does not engage the locking mechanism completely or at all, even though the user may be convinced upon visual examination that the backrest is properly locked. Only by pulling on the backrest can it be determined with absolute certainty whether the backrest is in a properly locked position. However, for reasons of convenience this test is frequently not performed. A backrest that is not properly locked, however, can become a fatal hazard for passengers, since a rear-end collision or heavy breaking can cause objects stored in the cargo space to enter into the passenger cabin like projectiles. 
   To prevent this from occurring, indicator devices have been developed that signal to the driver that the backrest of a backseat is not locked or not locked properly. 
   DE 102 30 637 A1 describes such a display device. The device includes an illuminating device, which signals through illumination whenever a backrest is not locked. In addition to the signal device, an actuating element of the display indicating an unlocked backrest is also provided. In locked position, the upper end of the actuating element is flush with a frame provided on the upper face of the backrest. To unlock the backrest, the actuating element is pulled upward. In this state, the actuating element projects above the upper face of the backrest and remains in this position when the backrest is unlocked. 
   A display of the same type for indicating that a vehicle seat backrest is not in locked position is described in JP 2001097009-A. In this commonly known solution, a separate indicator for signaling that the backrest is not in locked position is provided in addition to the actuation knob. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   An object of the invention is to eliminate the need for such separate indicator devices. 
   This object is achieved with an indicator for signaling that the vehicle seat backrest is not in a locked position in accordance with the teachings of the invention, as described below. 
   The inventive indicator signals when a vehicle seat backrest is not in a locked position; i.e., when the movable backrest of the vehicle seat is in an unlocked position. The indicator includes a housing, and an actuating knob guided axially in the housing. The actuating knob is pushed into its locked position by a compression spring, and a stop is provided and configured to prevent the actuating knob from extending further than a predetermined amount out of the housing. The actuating knob is configured to activate a locking mechanism via a transmission mechanism, thereby causing a backrest of a vehicle seat to be unlocked by pressing the actuating knob into the housing. The stop is displaced axially in the biasing direction of the compression spring during the unlocking process, so that the actuating knob is pressed by the compression spring against the displaced stop into its unlocked signaling position, in which the actuating knob, and hence an unlocked condition signaling portion of the actuating knob, projects substantially further out of the housing than the unlocked condition signaling portion does in the locked position of the actuating knob. 
   In accordance with the invention, an actuating knob, which when pressed down unlocks the backrest, functions at the same time as an indicator for signaling that the backrest is not in its locked position. 
   In accordance with the prior art, a known actuating knob was forwardly biased into its locked position by a compression spring, and a stop prevented the prior art actuating knob from being pressed beyond its locked position and out of its housing. The present invention teaches that a stop can be displaced during the inventive unlocking procedure, so that the compression spring can press the actuating knob against the displaced stop significantly further out of the housing than when it is in its locked position. 
   Advantageous embodiments of the invention are as described above and below. 
   Below the invention is described in further detail with reference to various embodiments. 
   Relative terms such as up, down, left, and right are for convenience and are not intended to be limiting. 
   The term movable is intended to include adjustable and folding, for example, in accordance with the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a cross section through the housing of a locking mechanism for a folding backrest of a vehicle seat with an actuating knob set to locked position according to a first embodiment of the invention. 
       FIG. 2  illustrates an actuating knob in accordance with  FIG. 1  pushed into unlocked position. 
       FIG. 3  illustrates an actuating knob in accordance with  FIG. 1  in a signaling position. 
       FIG. 4  illustrates a cross section through the housing of a locking mechanism for a folding backrest of a vehicle seat with an actuating knob set to locked position according to a second embodiment of the invention. 
       FIG. 5  illustrates an actuating knob in accordance with  FIG. 4  in unlocked position. 
       FIG. 6  illustrates an actuating knob in accordance with  FIG. 4  in signaling position. 
       FIG. 7  illustrates a cross section through the housing of a locking mechanism for a folding backrest of a vehicle seat with an actuating knob set to locked position according to a third embodiment of the invention. 
       FIG. 8  illustrates an actuating knob in accordance with  FIG. 7  in unlocking position. 
       FIG. 9  illustrates an actuating knob in accordance with  FIG. 7  in signaling position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Before the individual embodiments are described in further detail, the features common to all embodiments of the invention will first be stated. 
   Actuating mechanism  1  for unlocking an unillustrated folding backrest of a vehicle seat is provided in a housing  2 , which is secured to an upper portion of the bearing structure of the backrest. At the upper end of the housing  2  an actuating knob  3  is axially guided in the direction of double-ended arrow  4 . Disposed on the housing  2  is a guard  5 , which serves as an axial guide for the actuating knob  3 , and whose flange region  5 . 1  is disposed on the cover of the backrest when the housing  2  is assembled. A compression spring  6  presses the actuating knob  3  into its locked position illustrated in  FIGS. 1 ,  4  and  7 , in which the upper edge  3 . 1  is flush with the flange region  5 . 1  of the guard  5 . 
   The housing  2  also contains a locking mechanism  7 . This includes a rotary latch  8  and a ratchet  9 , which are each mounted in housing  2  pivotally about axes  10  and  11  mounted fixedly to the housing. In locked position ( FIGS. 1 ,  4  and  7 ) a crook  12  provided on rotary latch  8  hooks over a lug  13  from above that is mounted fixedly on the chassis, which runs through a recess  14  in a side wall  2 . 1  of the housing  2 . This locked position of the rotary latch  8  is secured by ratchet  9 , the end of which facing away from the pivot axis provides a catch  15 , which rests in a mating configured recess  16  of the rotary latch  8  shaped to fit it. The ratchet  9  and the rotary latch  8  are pulled toward one another by a tension spring  17 , the ends of which are secured to attachment points  18 ,  19  on ratchet  9  and rotary latch  8 , respectively. Pivoting the rotary latch  8  into its unlocked position ( FIGS. 3 ,  6  and  9 ), in which the crook  12  releases the lug  13  secured fixedly to the chassis, is only possible if the ratchet  9  has first been pivoted counterclockwise. This pivoting is activated by pressing the actuating knob  3  into the housing, wherein the actuating knob  3  is connected to the ratchet  9  via transmission means. These transmission means vary from embodiment to embodiment and are specified below. 
   In the embodiment illustrated in  FIGS. 1 through 3 , the transmission means includes a cable loop  20  to the end of which shoes  21  are clamped, which are pivotally attached to a stud  22  provided on the end opposite the pivot axis  11  of the ratchet  9 . The cable loop  20  is routed around an anchoring stud  23  mounted fixedly in the housing, forming a branch  20 . 1  and another branch  20 . 2 . 
   Attached fixedly on the branch  20 . 2  is a boss  24 , which is hung in a chamber  25  as in a Bowden cable, wherein the chamber  25  is situated on the lower end of the actuating knob  3 . In locked position both cable branches  20 . 1  and  20 . 2  are taut so that the boss  24  suspended in the chamber  25  serves as a stop for the actuating knob  3 . One end of the compression spring  6  makes contact with a ledge  26  mounted fixedly in the housing and the other end makes contact with the lower surface of the actuation knob  3 . Boss  24  prevents the actuating knob  3  from being pressed by the compression spring  6  any further out of the housing  2  than it is in locked position shown in  FIG. 1 , in which the upper surface  3 . 1  is flush with the flange  5 . 1  of the guard  5 . 
   To unlock the backrest the actuating knob  3  must be pressed into the housing  2  against the force of the compression spring  6  as shown in  FIG. 2 . The boss  24  is pulled along by this pressing movement; that is, force is exerted on branch  20 . 1 , in turn causing the ratchet  9  to pivot counterclockwise about the axis  11 . As a result, the catch  15  of the ratchet emerges from the recess  16  of the rotary latch  8  and comes to rest on a catch  27  of the rotary latch  8 , as  FIG. 2  illustrates. From this point on it is no longer necessary to further press the actuating knob  3 , since the tension spring  17  takes over the further opening of the rotary latch  8 . The catch  27  of the rotary latch  8  then slips onto the lower surface of the ratchet  9  as the ratchet  9  continues to pivot counterclockwise toward the turning axis  11  and to fall into a recess  28  of the ratchet, whereby the unlocked position of the rotary latch  8  is fixed. The pivoting of the rotary latch  8  out of the locked position and into the unlocked position causes the lug  13  to become released from the crook  12  of the rotary latch  8 , allowing the backrest to be folded forward. 
   By pivoting the ratchet  9  during the unlocking procedure, the stud  22  and thereby the cable loop  20  along with the boss  24  are displaced further upward in the direction of the compression spring  6  force from their locked state ( FIG. 1 ). The compression spring  6  can thereby press the actuating knob  6  no longer held into position by boss  24  into its signaling position, in which it projects significantly further from the housing  2  and guard  5 , respectively, than it does in its locked position. At least a portion of the outwardly extending region of the knob  3  may be termed an unlocked signaling portion. To enhance the signaling effect, it is advantageous if the actuating knob  3 , except for the upper surface  3 . 1 , is colored red. To prevent the spring  6  from pushing the actuating knob  3  completely out of housing  2 , stops  29  secured to the housing are provided. In signaling position, a bottom flange  30  of actuating knob  3  makes contact with one of the stops, while an upper edge  25 . 1  of housing  25  of boss  24  makes contact with the other stop. 
   When the backrest is moved or folded back to its upright position, the lug  13  mounted fixedly to the chassis strikes the contact surface  12 . 1  of the crook  12  of the rotary latch  8 . As a result, this pivots clockwise, whereby its catch  27  runs along the lower surface of the ratchet  9  until the catch  15  of the ratchet  9  falls back into recess  16  of rotary latch  8 , whereby the locked state as illustrated in  FIG. 1  is achieved. As long as the backrest is not locked and lug  13  mounted fixedly to the chassis is thereby not engaged by the crook  12  of the rotary latch  8 , the actuating knob  3  projects from the guard  5 , signaling that the backrest is not properly locked. 
   In the embodiment illustrated in  FIGS. 4 through 6  the transmission means includes a rocker  31  and a transmission lever  32 . The rocker  31  is pivotally mounted on an axis  33  fixedly mounted in the housing. At the end of one rocker arm  31 . 1  the end of the transmission lever  32  is connected at a pivot point  34  by a swivel joint. The other end of the transmission lever  32  is connected to the end of the ratchet  9  opposite the axis  11  at a pivot point  35  by a swivel joint. 
   At the ends of arms  31 . 1  and  31 . 2  of rocker  31  are a stop  36  and a stop or actuating stop  37 , respectively. When the actuating knob  3  is in locked position, stop  37  makes contact with the lower surface of the actuating knob  3 , while stop  36  abuts an extension  38  of the actuating knob  3  above. 
   To release locking mechanism  7 , the actuating knob  3  is pressed downward into the housing  2  against the force of the compression spring  6  as  FIG. 5  illustrates. Owing to the downward pressing movement of the actuating knob  3 , the rocker  31  is pivoted counterclockwise via the stop  37  provided at the lower surface of the actuating knob  3 . As a result of this pivoting motion, the stop  36  provided on the other arm  31 . 1  of the rocker  31  is displaced upward, while tension is exerted on the transmission lever  32 , which extends to ratchet  9 , and causes it to pivot counterclockwise. The remaining steps of the unlocking procedure are substantially the same as those of the previous embodiment, to which the reader&#39;s attention is directed. 
   Through the unlocking procedure, stop  36  is displaced upward from its position in the locked setting ( FIG. 4 ) in the biasing direction of compression spring  6 . If the actuating knob  3  is released, it is then driven by the compression spring  6  against the stop  36  upward and out of the housing  2  into its signal position illustrated in  FIG. 6 . 
   When the backrest is returned to its upright position and is properly locked, the components automatically return to their initial state illustrated in  FIG. 4 . 
   In the embodiment illustrated in  FIGS. 7 through 9 , the transmission means includes two transmission levers  39 ,  40 . The transmission lever  39  is guided in an axial guide  41  of the housing  2  in the actuation direction of knob  3 . When the actuating knob  3  is in locked position, the upper end of the transmission lever  39  is provided at the lower surface of the actuating knob  3  or is disposed slightly offset therefrom, as  FIG. 7  illustrates. The other end of the transmission lever  39  is connected by use of a swivel joint to the end of the transmission lever  40  at a pivot point  42 , while the other end of the transmission lever  40  is connected at pivot point  43  by a swivel joint to the end of a lever arm  9 . 1 , which is connected to a two-armed ratchet  9  in this embodiment. The lever arm  9 . 1  extends diametrically to the lever arm  9 . 2  of the ratchet  9 , on which a catch  15  is provided as in the previous embodiments. 
   A shock absorber or damper  45  is pivotally connected to the end of the lever arm  9 . 2  of the ratchet  9  via a coupling  44 . This damper  45  includes as usual a housing  46  as well as a compression spring  47  and a piston rod  48  disposed therein. The end of the piston rod  48  is pivotally connected to the actuating knob  3  via an additional coupling  49 . For effective kinematics, the damper  45  is disposed in a guide  50  secured to the housing, so that it cannot exert any pitch on the couplings  44  and  49 . 
   Provided on the end of the piston rod  48  projecting into the housing  46  is a disc  48 . 1 , an end of which makes contact with the compression spring  47 . The other end of the compression spring  47  makes direct contact with the lower front wall  46 . 2  of the housing  46 . In locked position, the compression spring  47  presses the disc  48 . 1  of the piston rod  48  to the upper front wall  46 . 1  of the housing  46 . The disc  48 . 1  and front wall  46 . 1  together form a stop, which prevents the actuating knob  3  from being driven by the compression spring  47  out of locked position ( FIG. 7 ) and the housing  2 . 
   To unlock the locking mechanism  7 , which, except for the above-described variation in the ratchet  9 , is substantially the same as the locking mechanisms  7  of the previous embodiments, the actuating knob  3  is pressed into the housing  2 , as illustrated in  FIG. 8 . As a result of this action, the ratchet  9  is pivoted counterclockwise via the transmission lever  39 ,  40 , while the compression spring  47  of the damper  45  is tensioned. This tensioning of the compression spring  47  results from two movements. It results from the action of the actuating knob  3  being pressed down and thereby driving the piston rod  48  into the housing as well as from the pivoting movement of the ratchet  9 , whereby the entire damper  45  is shoved upward into guide  50 . The shifting of the damper  45  upward is continued by the kinematics of the unlocking process, which are identical with those of the previous embodiments. After the actuating knob  3  is released, the compression spring  47  of the damper  45  can be relaxed, causing the piston rod  48  to be shifted out of the housing  46 . This movement is transmitted via the coupling  49  and exerted on the actuating knob  3 , causing it to extend out of housing  3  and into its signaling position. The signaling position of the actuating knob  3  results from the striking of the disc  48 . 1  on the upper front face  46 . 1  of the housing  46  of the damper  45  ( FIG. 9 ). 
   The locked position as illustrated in  FIG. 7  is achieved by folding the backrest into its upright position, wherein the lug  13  mounted fixedly to the chassis is hooked by the crook  12  of the rotary latch  8 . 
   While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.