Abstract:
A manual lever drive for an adjusting device on a seat for converting a lifting movement into a discontinuous rotational movement has a support arm and a step-by step mechanism having an output member and an input member. The output member is configured to be coupled with a rotatingly moveable control member of the adjusting device. A transmission member is connected to the input member for torque transmission onto the input member. A manual lever is connected to the support arm so as to pivot about a first axis of rotation. The manual lever is configured to actuate the transmission member. The transmission member is arranged on the input member providing a second axis of rotation. A pivot angle of the manual lever imparts to the transmission member a pivot movement increasing a corresponding pivot angle of the second axis of rotation.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/EP01/03319, filed on Mar. 23, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a manual lever drive for adjusting devices on seats, in particular, motor vehicle seats, for converting a lifting movement into a discontinuous rotation movement by employing a step-by-step mechanism. 
     2. Description of the Related Art 
     In today&#39;s vehicles, self-locking gears or ratchet gears are used for adjusting different positions, such as, for example, the slant adjustment of the back rest, the seat height adjustment or the adjustment of the seat surface slant. Self-locking gears or ratchet gears, for example, in the form of simple planetary gears, are able, when configured accordingly, to receive loads occurring possibly in an accident situation, independent of whether at the moment of the accident an adjustment process was carried out or not. In many cases, the adjustment in the end is carried out by a rotational movement which however cannot be easily and comfortably performed because of lack of space. As an example, the problem in regard to operating the rotary adjuster for the back rest is mentioned in this context which is to be adjusted by an actuator hand wheel which is often arranged so closely to the inner parts of the car body that an ergonomic operation cannot be realized. 
     Step-by-step mechanisms for converting two-way alternating lifting movements into a discontinuous rotational movement are used already in many variations in the field of motor vehicle seats; frequently, ratchet gears and free wheel brake roller configurations are used. In order to realize an ergonomic operation, in many cases rotatory step-up or step-down gears are used after conversion of the lifting movement into the rotational movement in order to bring the forces and adjusting parameters into the required ratio relative to one another. A plurality of these employed mechanisms require for a correct function internal control paths for their activation; for example, in the case of ratchet gears a pawl must first be brought into engagement before the movement can be finally transmitted. Accordingly, of the entire movement to be provided by the operator only a minimal portion can be utilized for the actual adjustment so that the “total mechanical efficiency” decreases. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a manual lever drive for adjusting devices which eliminates the aforementioned disadvantages of known systems and with which particularly the initial rotational angle relative to the lifting angle introduced by the manual lever is enlarged. 
     In accordance with the present invention, this is achieved in that the output member of the step-by-step mechanism is coupled with a rotating adjusting member of the adjusting device while the input member of the step-by-step mechanism is connected to the transmission member actuated by the manual lever for torque transmission, wherein the manual lever is pivotably supported on a support arm and pivotable about a first axis of rotation and its respective pivot angle imparts to the transmission member, arranged on a second axis of rotation, a pivot movement enlarging the corresponding rotational angle of the second axis of rotation on which the input member of the step-by-step mechanism is arranged. 
     For the transmission of the travel stroke or of the rotational angle, a lever drive, which can be referred to as a kinetic transmission, is connected upstream of the conversion of the lifting movement into a rotational movement; this provides, on the one hand, a very simple inexpensive realization and, on the other hand, with a corresponding selection of the transmission ratio, the control path required in the downstream system is also transmitted so that with regard to the actual actuation element the ratio of effective path to empty run is improved. In this connection, the actuation of such a lever drive can be configured, even for minimal space availability, in a comfortable way. Important in connection with the present solution are the two axes of rotation wherein on the first axis of rotation the manual lever is supported while the second axis of rotation represents the input member for the step-by-step mechanism, wherein the transmission member is fixedly connected with the input member forming the second axis of rotation, wherein the transmission member, in turn, can be actuated by the manual lever. As a result of the spacing of the axes of rotation from one another and as a result of the spacing of the second axis of rotation to the contact point of the manual lever on the transmission member, upon deflection of the manual lever by a certain angle a substantially greater angle results at the transmission member; consequently, a greater rotational angle on the second axis of rotation driving the step-by-step mechanism is realized. This reduces the empty run of the system which can be felt by the operator, the empty run being reduced according to the ratio of the aforementioned spacings. 
     In a first embodiment of the invention, the transmission member is a pivot lever fixedly connected to the input member which, by means of followers engaging opposed sides of the load arm of the manual lever, can be pivoted via the manual lever in one or the other rotational direction. In this connection, the followers of the pivot lever are advantageously pins projecting from the pivot lever and contacting control cutouts on the load arm of the manual lever. 
     In order to return the pivot lever after each switching step and thus also the manual lever into the initial position, the pivot lever has a return arm which is loaded by a stationary spring member and can thus be returned from any rotational position into a zero position. In this connection, the spring member can be in the form of a spiral spring secured on the housing of the step-by-step mechanism which engages with radially projecting spring fingers opposed sides of the return arm of the pivot lever. 
     Conventionally, the person adjusting the vehicle seat is seated on the seat and exerts, because of the person&#39;s weight, a load on the adjusting element against which the position is to be adjusted with fine adjusting steps. For this purpose, a correspondingly great actuation force is to be applied which, however, to the seat occupant appears to be normal and is thus acceptable. However, when the seat is to be adjusted from the outside, i.e., when the operator is stands next to the vehicle, it is desirable to obtain a quick adjustment of the seat with a few pumping movements. These two aforementioned typical different operating states require for a consequent realization also different transmission ratios. A high transmission ratio of, for example, 1:4 in the case of the unloaded seat to be quickly adjusted is desirable while, when the seat is loaded, a minimal transmission ratio is desired for a precise and fine adjustment. For realizing these possibilities, according to a further embodiment of the invention, the pivot lever, which is provided as the transmission member, is formed by a spring saddle and a lever bracket connected thereto which receives in a contacting way between its two spaced-apart spring legs an end portion of the load arm of the manual lever which end portion is provided with curved control surfaces. In this connection, the leaf-spring-like spring legs are fixedly correlated with the pivot lever wherein the contact between the control surfaces on the load arm of the manual lever and the spring legs of the pivot lever is closer to the second axis of rotation than the contact point between the control surfaces and the spring legs for a somewhat pivoted load arm of the manual lever. In this connection, in the case of a great counter load on the pivot lever, the loaded spring leg experiences such a load that bending of the spring about the clamping location occurs and, in cooperation with the correspondingly curved control surfaces on the end portion of the load arm of the manual lever, the spring leg experiences a displacement of the contact point away from the second axis of rotation to the rear. This causes an automatic change of the transmission ratio. The transmission changes load-dependently by using the aforementioned spring legs, which are mentioned only as an example and which form elastic elements within the transmission chain. Accordingly, for such an arrangement first the empty run angle of the step-by-step mechanism arranged downstream is passed quickly with minimal load and thus high transmission while the subsequent loading of the seat adjusting element leads to a continuous reduction of the transmission and thus an ergonomic operation. 
     A further transmission, which is adjustable automatically as a function of the load but in steps, is provided by a spring saddle secured on the lever bracket of the pivot lever which has a U-shaped support body having on the lateral legs engaging the load arm of the manual lever a multi-step spring bracket, respectively, between which the load arm of the manual lever with its contact sections engages continuously during its pivot movement. In this connection, each spring bracket can have, for example, three spaced-apart, successively arranged bracket sections which successively become narrower and engage the clamping projections on the load arm of the manual lever with increasing clamping force. Thus, three load stages are provided wherein the individual bracket sections are configured such that the force required for pressing apart the clamping sections increases with increasing spacing of the corresponding clamping section from the second axis of rotation. For smaller output moments, the force is transmitted via the bracket section closest to the axis of rotation so that for small loads a great transmission is realized. The force which can be transmitted at this location is limited by the opening force of the clamping section. When the output load increases to a level above the transmittable force on the first bracket section, the force is transmitted by the second bracket section which is farther removed from the axis of rotation. Accordingly, the transmission ratio at this location is smaller than before. The aforementioned statements apply analogously to the exemplary third contact location of the corresponding bracket section. 
     Instead of a transmission ratio which changes automatically upon actuation of the manual lever, it would also be possible to provide a device with which the transmission ratio is controlled in a targeted way. This could be realized, for example, in that on the manual lever a pushbutton is arranged which, by means of a sliding linkage, is connected to a connecting link bracket which is movable relative to the load arm of the manual lever as well as with regard to the bracket lever; by means of the connecting link bracket, when the user actuates the pushbutton, a constructively fixed transmission is activated in order to achieve, for example, a quick adjustment at a high transmission ratio. 
     The afore described embodiments of a transmission mechanism are arranged upstream of a step-by-step mechanism. Instead, an embodiment of a lever drive can be provided wherein the step-by-step mechanism is integrated in a special embodiment. For this purpose, according to an advantageous embodiment of the invention, the transmission member is comprised of a spool body fixedly connected on the shaft of the second axis of rotation and a wrap spring surrounding it. The wrap spring has spring ends formed as elastic follower arms between which a curved head of a load arm of the manual lever is received. In this connection, the follower arms of the wrap spring advantageously are loaded by one spring member, respectively, in the direction of a zero position, respectively. The elastic follower arms of the wrap spring serve however not only for controlling the coupling function but, at the same time, are formed as contact surfaces for the curved head on the load arm of the manual lever. These contact surfaces bend load-dependently and enable thus a high functional integration. For a pivot movement of the load arm of the manual lever in one direction, the wrap spring is closed for this movement direction and the spool body, for an initially high transmission, is entrained wherein the transmission ratio as a result of gliding of the curved head on the corresponding follower arm is adjusted automatically to the load. Upon pivoting of the load arm of the manual lever into the initial position, the previously driven follower arm is loaded by the restoring spring member such that the wrap spring is opened and the spool body is no longer driven but instead, as a result of friction in the downstream adjusting element of the seat, remains in this position. Since for a corresponding pivot movement of the load arm of the manual lever in the opposite direction, the aforementioned effect happens also, but in the opposite direction, a step-by-step mechanism acting in both directions is realized with integrated automatic load-dependent transmission. 
     A further embodiment of a step-by-step mechanism integrated with the lever drive can be preferably obtained in that the transmission member is formed by a drum-shaped cup fixedly connected to the shaft of the second axis of rotation and a wrap spring arranged therein. The wrap spring has spring ends in the form of follower arms radially projecting toward the drum-shaped cup center which are received in the receiving space of a pawl arranged on the load arm of the manual lever. Since depending on the configuration of the seat adjusting element, the inner friction is possibly reduced in comparison to the friction upon return of the wrap spring, it may be advantageous to employ two wrap springs acting in opposite directions, respectively, the configuration being identical in other respects, so that restoring springs can be eliminated, if needed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawings: 
     FIG. 1 shows a first embodiment of a manual lever drive for triggering an unchangeably transmitted adjusting stroke in a step-by-step mechanism, illustrated in a schematic, perspective illustration; 
     FIG. 1A shows the lever drive of FIG. 1 in a schematic side view at a reduced scale wherein the lever drive is in the zero position; 
     FIG. 1B shows the lever drive illustrated in FIG. 1A, also in a side view, in a position pivoted out of the initial (zero) position; 
     FIG. 2 shows a further embodiment of a lever drive whose transmission ratio during the lever pivot action is automatically continuously adjustable, also illustrated in a schematic, perspective illustration; 
     FIG. 2A illustrates the lever drive of FIG. 2 in a schematic side view at a reduced scale wherein the manual lever is in the zero position; 
     FIG. 2B shows the lever drive illustrated in FIG. 2A in a side view wherein, upon pivoting of the manual lever, the pivot lever has also been pivoted in a corresponding way; 
     FIG. 3 shows a modification of the lever drive illustrated in FIG. 2 in a schematic, perspective illustration wherein the pivot lever is configured for a multi-step transmission ratio; 
     FIG. 4 is a further embodiment of a lever drive, also in a schematic, perspective illustration wherein the step-by-step mechanism has been integrated into the transmission member by using a wrap spring; 
     FIG. 4A shows the step-by-step mechanism illustrated in FIG. 4 in a schematic side view at a reduced scale in which the load arm of the manual lever provided with a curved head is in the zero position; 
     FIG. 5 shows a further embodiment of a lever drive in a schematic, perspective illustration wherein a wrap spring actuatable by the load arm of the manual lever is arranged within the interior of a drum-shaped cup; 
     FIG. 6 shows an embodiment, modified relative to FIG. 5, in an analog illustration in which the transmission ratio of the lever drive can be selected. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Firstly, it is to be noted that in the illustrated embodiments only those components are illustrated which are required for understanding the subject matter of the invention. Neither the adjusting devices in the form of, for example, the aforementioned adjusting brackets for adjusting and moving the back rest of the vehicle seat or the seat-adjustment or the adjustment of the slant of the seat surface are therefore illustrated since they are not required for understanding the invention, nor are the details of a step-by-step mechanism which can be embodied as is known in the art. 
     The lever drive  1  illustrated in FIG. 1 has a support arm  10  which is stationarily secured by means of fastening bores  12 . Its bearing bore  11  is penetrated by a bearing bolt, not illustrated, which, in turn, supports rotatingly the receiving bore  14  of a manual lever  13 . The manual lever  13  is formed as a two-arm lever relative to its point of rotation and has a force arm  15  provided with a grip part  17  which is separated by the receiving bore  14  from the load arm  16 . At a certain spacing to the receiving bore  14 , this load arm  16  has at its two longitudinal opposed sides control cutouts  18  which are engaged in a contacting way by followers  21  in the form of pins  22  of a pivot lever  20  acting as a transmission member  19 . At a certain spacing to the plane of the pins  22  in the direction toward the first axis of rotation  24  defined by the centers of the bearing bore  11  and of the receiving bore  14 , a follower bore  23  is arranged in the pivot lever  10 ; this follower bore  23  is fixedly connected to the input member  26  forming a second axis of rotation  25  which can be in the form of a shaft provided with profilings for rotational entrainment and extending into a step-by-step mechanism  27 . The rotational movement which is introduced by the input member  26  into the step-by-step mechanism  27  is transmitted by the step-by-step mechanism via an output shaft  28  to a control member of a non-illustrated adjusting device which can be, for example, the joint fitting for slant adjustment of the back rest of a vehicle seat. On the end of the pivot lever  20  projecting past the follower bore  23 , the pivot lever  20  is provided with an angled return arm  29  which can be returned by a stationarily secured spring member  30  from any rotational position into the zero position. As is illustrated in FIG. 1, the spring member  30  can be a spiral spring  31  secured on the housing of the step-by-step mechanism which, by means of radially projecting spring fingers  32 , engages opposed sides of the return arm  29  of the pivot lever  20 . In the embodiment according to FIG. 1, between the pins  22  a follower bore  33  is provided in the pivot lever  20  with which a locking pin  34  of the step-by-step mechanism  27  can be actuated. 
     FIG. 1A illustrates the initial position, which is to be referred to as the zero position, in which the manual lever  13  as well as the transmission member  19  in the form of the pivot lever  20  are not subjected to any angular deflection. Only when the manual lever  13  is pivoted (lifting movement  70 ) by the angle αH illustrated in FIG.  1 B—in the present case in the downward direction—a rotational movement  80  with a pivot angle αA results for the second axis of rotation  25  caused by the entrainment of the pins  22  on the pivot lever  20  functioning as the transmission member  19 . The purely schematic illustration of FIG. 1B shows that the pivot angle αA of the pivot lever  20  is greater by a multiple in comparison to the pivot angle αH of the manual lever  13  pivoted about the first axis of rotation  24 . The magnitude of the transmission depends on the ratio of the spacings between the axes of rotation  24  and  25 , on the one hand, and the spacing between the axis of rotation  25  and the force action point on the loaded pin  22 . 
     In the embodiment illustrated in FIG. 2 the first axis of rotation  24  is also provided by the bearing of the manual lever  13  with its receiving bore  14  relative to the bearing bore  11  of the support arm  10 . The load arm  16  of the manual lever  13  has at its free end an end portion  35  which at its upper side as well as its bottom side has control surfaces  36 . These control surfaces  36  are engaged by a spring saddle  37  which is connected to a lever bracket  38  and together with it forms a pivot lever  20  which functions as the transmission member  19 . In addition to the fastening bores for the spring saddle  37 , the lever bracket  38  has a follower bore  39  which is engaged in a torque-transmitting way by the aforementioned input member of the step-by-step mechanism, not illustrated in FIG. 2, wherein the center of the follower bore  39  and the center of the input member define the second axis of rotation  25 . The spring saddle  37  is U-shaped and has lateral legs  40  projecting relative to its stay which legs  40  contact the control surfaces  36  on the end portion  35  of the load arm  16  of the manual lever  13 . 
     When, starting from the zero position of the manual lever  13  illustrated in FIG. 2A, the manual lever  13  is pushed downwardly by the angle αH, the contact point  41  of the control surface  36  moves on the spring leg  40  relative to the second axis of rotation  25  radially away from it into the position illustrated in FIG.  2 B. When doing so, optionally with bending open of the upper of the spring leg  40  resting against the upper control surface  36 , the pivot lever  20  belonging to the transmission lever  19  is pivoted upwardly about the second axis of rotation  25  in a counterclockwise direction into the angular position αA; at the same time, the second axis of rotation is also rotated by the angle αA. As illustrated particularly in FIG. 2B, the angle αA is greater by a multiple in comparison to the angle αH. Since upon further pivoting of the manual lever  13  the contact point  41  is also further moved in the radial direction, during the pivot movement of the manual lever  13  an automatic continuous change of the transmission ratio takes place so that the force ratios are changed also in the aforementioned sense. 
     An embodiment modified relative to FIG. 2 is illustrated in FIG.  3 . Here, a modified spring saddle  37 ′ is secured on the lever bracket  38  which together with the lever bracket  38  forms the pivot lever  20 . The spring saddle  37 ′ is comprised of a U-shaped support body  42  and of multi-step spring brackets  43  wherein a spring bracket  43  is secured on each leg  44  or  45  of the support member  42 . In the embodiment illustrated in FIG. 3, each spring bracket  43  has three spaced-apart, successively arranged bracket sections or contact sections  46  which are bracket-shaped and which can come into contact with the load arm  16  of the manual lever  13  when the load arm  16  pivots. In this connection, the contact section  46  closest to the first axis of rotation  24  is bent open farther than the following one and the latter, in turn, is again opened somewhat farther than the final one ( 46 ) which is positioned farthest away from the axis of rotation. In this connection, the load arm  16  advantageously has clamping projections  47  at the locations cooperating with the contact sections  46  which, upon corresponding loading, can penetrate between the respective contact sections  46  of the spring bracket  43  and thus pivot the pivot lever  20  by means of the spring bracket  38  such that the second axis of rotation  25  undergoes a corresponding angular rotation and transmits it also to the non-illustrated step-by-step mechanism. For a minimal force introduction by the adjusting device onto the lever drive upon deflection of the manual lever  13 , only the forward contact section  46 , positioned above or below the load arm  16  depending on the pivot direction of the manual lever, is actuated for a pivot movement by the corresponding clamping projection  47 . Only when a greater force acts on the pivot lever  20 , the clamping projections  47  closest to the first axis of rotation  24  penetrates between the spring legs of the corresponding first contact section  46  so that the subsequent second contact section is loaded by the load arm  16  until the force is increased such that finally also the contact section  46  farthest from the first axis of rotation  24  is loaded. Accordingly, with this solution a changeable transmission ratio becomes effective, however, not continuously but so as to be changed in steps. Otherwise, the angular ratios which have been described in the preceding embodiments are also present. 
     In the embodiment illustrated in FIGS. 4 and 4A the manual lever  13  is again supported on a first axis of rotation  24  on the stationary support arm  10 . The load arm  16  of this manual lever  13  has at its free end a curved head  48  which engages between the spring ends  50  of the wrap spring forming elastic followers  21 . The wrap spring  49 , in turn, is arranged on the mantle of a spool body  51  and entrains it by friction as a result of its spring force in the corresponding rotational direction in the case of pivoting of one follower  21 . The spool body  51  has at its center, for example, a profiled follower bore  23  which, in turn, receives an input member for the adjusting device. The center of this follower bore is to be viewed as the second axis of rotation  25  which is arranged at a spacing from the first axis of rotation  24  supporting the manual lever  13  on the support arm  10 . Each follower of the wrap spring  49  is loaded for the purpose of zero position return by a stationarily supported spring member  52  (FIG. 4 a ). Upon introduction of a lifting movement into the manual lever  13 , the respective follower  21  of the wrap spring  49  is pivoted via the curved head  48  so that a rotational entrainment of the spool body  51  in the corresponding pivot direction is realized and, moreover, the drive member forming the second axis of rotation  25  is also rotated. By means of the curve of the curved head  48  and the correspondingly shaped spring end  50 , an automatic continuous change of the transmission ratio, based on the deflection angle of the manual lever  13 , to the deflection angle of the follower  21  of the wrap spring loaded by the curved head  48  takes place during the pivot movement of the manual lever  13 . When the manual lever  13  after deflection is set to be free of force loading, a return of the respective follower  21  and thus a return of the manual lever  13  into the position illustrated in FIG.  4  and FIG. 4A is realized without the spool body  51  being rotated, at least when a self-locking adjusting device is arranged downstream of the spool body  51  and, in this way, the input member connected to the follower bore  23  is secured. 
     The embodiment illustrated in FIG. 5 is again a modification of the embodiment illustrated in FIGS. 4 and 4A. In this case, the manual lever  13  is also supported by means of the first axis of rotation  24  on the stationarily arranged support arm  10 . The second axis of rotation  25  is formed by an input member, not illustrated in FIG. 5, arranged in the follower bore  23  wherein the follower bore  23  is a component of a drum-shaped cup  53  in whose interior a wrap spring  49  is arranged. In this connection, the wrap spring  49  and the drum-shaped cup  53  form the transmission member  19 . This wrap spring  49  has also spring ends forming followers  21  which are engaged by a pawl  54  at the end of the load arm  16  of the manual lever  13 . The function of this embodiment is realized in the same way as in the embodiment of FIGS. 4 and 4A. 
     The embodiment of FIG. 6 illustrates a modification of the embodiment of FIG.  5 . The pawl  54  is configured as a guide rail on the load arm  16  of the manual lever  13  on which a connecting link bracket  57  is slidably arranged wherein the sliding stroke in the direction toward the first axis of rotation  24  is limited by a stop  59  on the load arm  16 . A sliding linkage  56  is connected to the connecting link bracket  57  and is connected to a pushbutton  55  arranged on the grip part  17 . When pressing the pushbutton  55 , the bracket  57  with its contact points  58 , in the form of beads configured for contacting the followers  21 , is moved relative to the second axis of rotation  25  to the rear so that the transmission ratio changes. Accordingly, the operator can select the transmission ratio by means of the actuating device comprised of the components  55 ,  56 ,  57  and maintain it by pressing the pushbutton  55 . Only after releasing the pushbutton  55 , the bracket  57  is returned into the initial position illustrated in FIG. 6 by means of the restoring spring  60  arranged between the bracket  57  and the load arm  16  of the manual lever  13 . The restoring spring could, of course, also be integrated for loading the pushbutton  55  within the grip  17 . 
     As already mentioned, the illustrated embodiments of the subject matter of the invention are only to be understood as examples. The invention is not limited to these embodiments. Instead, several configurations and modifications of the subject matter of the invention are conceivable. In particular, all features which are disclosed in the drawings and in the description are important to the invention even though they are not expressly claimed in the claims. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.