Abstract:
The invention is related to an actuator, especially for seat adjusting devices with at least one electrical engine having subordinated reduction gear and a disconnecting device for manual operation. The task of the present invention is to provide a generic actuator with a disconnecting device that can be used in all operating processes in a large number of different applications and that guarantees reliable functioning of the disconnecting device without being over-dimensioned and thus uneconomical. This problem is solved according to the invention as follows: The disconnecting device has a coupling insertion spring which determines the release force of the disconnecting device and a reset spring is provided which resets an actuating means.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (1) Field of the Invention 
         [0002]    The invention is related to an actuator, especially for seat adjusting devices having at least one electric motor with a subordinate reduction gear and a disconnecting device for manual operation. 
         [0003]    (2) Description of the Related Art 
         [0004]    Electrical actuators are for comfort or adjustment of inaccessible adjusting links. In case of a voltage failure or other such defects, it should be possible to adjust the links manually; this is normally the case with seat elements too. As actuators usually have high-reduction, partly self-locking reduction gears, a manual adjustment to create the required torque is possible only with the help of a coupling between the electric motor and the reduction gear or within the reduction gear. 
         [0005]    An actuator for seat adjustment devices is known from DE-OS 102 30 591, in which the drive path between an electric motor and an output means of the actuator can be interrupted manually, where a traction rope transfers the force of a manually activated lever to a disconnecting device, which blocks the gear ring of a planetary gear against rotation during the operation of the electric motor, but allows rotation in the manual mode. 
         [0006]    The known disconnecting device covers a single reset spring which tries to maintain the engaged position of the disconnecting device on the one hand, and resets the manually operated lever on the other hand. As such disconnecting devices are not designed for a single application for economical reasons, and it must be possible to adapt them to a large number of installation geometries, the disconnecting device must be designed to withstand all expected forces. Traction ropes have the unique property that the rope length protruding from a rope supporting system changes according to the number and amount of bending angles in the rope course. This longitudinal change leads to a partial disengagement of the disconnecting device so that under unfavorable conditions, the gear ring can be released without activating the manually operated lever, while it remains securely locked in other installation geometries. Moreover, the friction ratios of the traction rope can be influenced by different bending angles so that the insertion force which feeds the reset spring is not adequate in each and every case to ensure a safe insertion of the disconnecting device. In applications in which the traction rope of the Bowden control cable follows the movement of the adjustment, this factor can lead to situations in which the coupling disengages. This would make the actuator ineffective. 
         [0007]    Hence, the task of the present invention is to provide a generic actuator with a disconnecting device that can be used for a large number of different applications and installation conditions and that guarantees a reliable function of the coupling device in all processes and methods without being over-dimensioned and therefore uneconomical. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    According to the invention, this problem is solved by the fact that the disconnecting device has a coupling insertion spring that defines the release force of the disconnecting device and that a reset spring is provided which resets an actuating means. An additional spring can be used to make the insertion movement of the disconnecting device and a resetting of the actuating means independent of each other, so that the insertion force of the coupling becomes independent of the use location and use type. 
         [0009]    In a specially preferred design model of the invention, the actuating means is connected to the disconnecting device through a free movement device. This arrangement enables the following: the movements or arrangements of the Bowden control cable do not have any influence on the disconnecting device, especially on the coupling means. Thus, for instance, even if the Bowden control cable moves during the adjustment, no inadvertent undesirable interruptions are caused in the adjustment, because the clearance compensates any possible longitudinal change of the traction rope. 
         [0010]    The invention envisages that the free movement device be designed as a free swivel device, where the free swivel device consists of a traction lever and a driver lever, both having a common swivel axis. 
         [0011]    An especially simple structure is possible if a traction rope of a Bowden control cable is connected to a traction lever on the one hand and to an actuating means on the other hand, especially if the reset spring is guided through the traction rope of the Bowden control cable. This way the longitudinal axis of the reset spring too can describe an arc without limiting its effectiveness. In this arrangement, the reset spring is supported by the traction lever on one side and by a supporting surface fixed permanently to the housing on the other side. 
         [0012]    Similarly as in the state of the art, it is provided in a design model of the invention that a counter-coupling means is mounted on a coupling means of the disconnecting device in swivel condition around the swivel axis. This arrangement is simple to implement and it allows a reliable operation of the disconnecting device. The swivel mounting of the counter-coupling means permits a large number of possible installation locations for the coupling insertion spring. 
         [0013]    It is preferred that the coupling insertion spring be connected to a drive lever through a coupling shaft or to a one-piece supporting means, on one hand, and to a supporting surface attached permanently to the housing, on the other hand. The coupling insertion spring can be supported on an extension mandrel in this context. Alternatively, the coupling insertion spring can be supported on the drive lever on the one hand and on a supporting surface attached permanently to the housing on the other hand. 
         [0014]    A compression spring, a spring clip or a spiral spring is ideally suited to function as the coupling insertion spring. A compression spring is preferably used for the reset spring. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    A design model of the invention is described in greater detail in the following pages with the help of the drawing. The following figures are displayed: 
           [0016]      FIG. 1  is a perspective view of a disconnecting device according to the state of the prior art, 
           [0017]      FIG. 2  is a perspective view of an actuator with a corresponding disconnecting device according to the state of the prior art, 
           [0018]      FIG. 3   a  is a schematic representation of a disconnecting device according to the invention, in a normal status, 
           [0019]      FIG. 3   b  is a schematic representation of the disconnecting device according to the invention, in an intermediate status, 
           [0020]      FIG. 3   c  is a schematic representation of the disconnecting device according to the invention, in a disengaged condition and with drawn actuating means, and 
           [0021]      FIG. 3   d  is a schematic representation of the disconnecting device according to the invention, in a disconnected condition and with reset actuating means. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
         [0023]      FIG. 1  shows parts of an actuator  1  according to the state of the prior art, with a planetary gear  9  consisting of a sun gear  20  attached to a shaft  22 , planet gears  21  that are mounted on a planet carrier (not shown) and a gear ring  5  that is simultaneously an integral part of a disconnecting device  4 . The gear ring  5  has a coupling means  7  formed from a ring  17  on its peripheral side  6  as cutouts in which the counter-coupling means  8  intervenes on being impacted by a spring. The coupling means  7 ,  8  are mutually coordinated in such a way that a clearance-free coupling connection results in the coupled condition. The counter-coupling means  8  is a part of a swivel device  23  consisting of a coupling shaft  18 , the ends of which are either integrated into one piece, or connected permanently to a traction lever  11  on one side and a counter-coupling means  8  on the other side. Together with one of these rotary bearings fixed to the housing, the coupling shaft  18  forms a swivel joint  15 , where the swivel device  23  consisting of a coupling shaft  18 , traction lever  10  and counter-coupling means  8  can swivel around a swivel axis  19 . The coupling shaft  18  has a supporting means  24  facing the counter-coupling means  8  which is impacted by a coupling insertion spring  12  guided to an expansion mandrel  13  in such a way that the gear ring  5  of the planetary gear  9  is locked against rotation in the normal operation mode. The expansion mandrel  13  has a set base  14  that supports the coupling insertion spring  12  as a compression spring. The disconnecting device  4  can be disengaged manually over a Bowden control cable  10  (only indicated here). 
         [0024]      FIG. 2  illustrates an actuator  1  according to the state of the prior art, having a housing  16  (displayed as opened) in which the following items are arranged: planetary gear  9  with the sun gear, planet gears, a planet carrier  25  and the gear ring  5 , the coupling means  7  arranged on the peripheral side of the gear ring as a first component of the disconnecting device  4 , the swivel device  23  consisting of the counter-coupling means  8 , the coupling shaft  18  that is mounted in the housing  16  and the traction lever  11  that is in active connection with the Bowden control cable  10 . 
         [0025]    The Bowden control cable  10  that is held in place by a support  26  impacts the traction lever  11  and swivels the coupling shaft in the process and therefore, also the counter-coupling means  8  against the force of the coupling insertion spring  12  from the coupling means  7 . To achieve zero clearance, coupling means  7  and counter-coupling means can be designed in the shape of a trapezium, so that the spring force of the coupling insertion spring  12  always takes care of adjacent coupling surfaces. 
       Existing Functioning According to the State of the Art 
       [0026]    With the Bowden control cable not activated, the compression spring  12  holds the counter locking means  8  in its grip without any clearance with one of the latching means  7  and ensures that the gear ring  5  is quasi attached to the drive housing. This enables the operation of a customary actuator consisting of an electric motor and a reduction gear for setting an adjusting unit, e.g., a seat element, where the sun gear  20  drives the planet gears  21  interlocked with the gear ring  5  and therefore, the planet carrier that functions as the output of this gear level of the actuator. If the Bowden control cable is activated, the traction lever  11  swivels, and the counter-coupling means  8  connected via the coupling shaft  18  with the traction lever  11  around the swivel axis  19 , where the counter-coupling means swivels away laterally from the coupling means  7 . The swivel movement displaces the expansion mandrel  13  in its axial direction by the supporting means  24 , which presses the compression spring  12  over the base  14 , stretching it, so that an insertion movement of the counter coupling means with the Bowden control cable released takes place automatically. If necessary, the gear ring is locked only after activating the electric motor, as soon as the counter-coupling means  8  is brought in agreement with one of the coupling means  7 . 
         [0027]    In the disconnected condition, the gear ring  5  can be rotated freely in the housing. A reverse counter force from the adjusting unit can no longer be accepted by the gear ring  5  in this condition, hence the planet gears  21  roll during manual activation of the adjusting unit (e.g., seat element) and the planet carrier driven by it on the sun gear, and carry the gear ring along. The Bowden control cable enables or simplifies manual activation. 
         [0028]    The protective scope of the invention is not limited to the displayed example, because it is possible to think in terms of a large number of alternative design models that also have different gear or coupling arrangements. 
         [0029]      FIG. 3   a  illustrates a schematic representation of a disconnecting device  4  according to the invention in a normal operation condition in which an actuating means  30  is in its normal position and the coupling that can be designed according to the state of the art, is locked. The actuating means  30  is connected to a traction lever  11  through a traction rope  27  of a Bowden control cable  10 , where the traction lever  11  is in a non-working position through a reset spring  33  that is guided from the traction rope  27 . The traction lever  11  is mounted on a coupling shaft  18  of the disconnecting device  4  around a swivel axis  19 , so that it can swivel. A drive lever  28  is stiffly fixed on the coupling shaft  18 . The coupling shaft  18  is mounted around the swivel axis  19  with the help of the drive lever  28  in such a way that it can swivel. The bearing positions (not shown here) are located in a housing of the actuator. The traction lever  11  can be swiveled against the drive lever  28 . 
         [0030]      FIG. 3   a  also shows a clearance  29  between traction lever  11  and drive lever  28 , which enables a limited free movement of the traction lever  11  without changing the insertion condition of coupling means  7 ,  8  of the disconnecting device  4 . A coupling insertion spring  12  supported on an expansion mandrel  13  works on the drive lever  28 . The coupling insertion spring is supported by a supporting surface  32  attached to the housing. The actuating means  30  is designed here in the form of a manually operated lever. In case of use in a seat adjustment device, the actuating means is arranged, e.g., in the top area of the backrest, so that a seat backrest adjustment may be possible manually in case of a power failure. 
         [0031]      FIG. 3   b  is a schematic representation of the disconnecting device according to the invention in the intermediate position in which the clearance  29  from  FIG. 3   a  is overcome and the dead movement clearance is removed from the arrangement. On activating the actuating means  30  further, the drive lever  28  also moves and with it the counter-coupling means  8 , as is known from DE 102 30 591 A1, starts disconnecting from the coupling means  7 . 
         [0032]    This movement is continued till the end status of  FIG. 3   c  is reached, in which the actuating means  30  is fully activated and the disconnecting operation is completed. In this condition, the element to be activated, i.e., a back support of an automobile or airplane seat can be brought to the desired position through manual adjustment. In the given example from DE 102 30 591 A1 (referring to  FIG. 1  and  FIG. 2 ), the gear ring moves during the manual adjustment to an intermediate position or incidentally in a locking position. If the actuating means  30  is allowed to go to an intermediate position, the status as illustrated in  FIG. 3   d  is maintained. 
         [0033]    The coupling is disengaged in  FIG. 3   d , where the drive lever  28  waits in an extreme position till the motor is activated again and it effects a synchronization of the coupling while the traction lever  11  was returned to its normal position by the reset spring  33 . The clearance  29  is now bigger than in the normal condition. During the synchronization however, the movement of the driver lever  28  is limited by the lock  7 ,  8  ( FIG. 1 ), so that the drive lever  28  is then reset to a position according to  FIG. 3   a  by the coupling insertion spring  12 . 
         [0034]    The schematic representation illustrates only one of the several possible variants. The arrangement and type of the coupling insertion spring  12  and the reset spring  33  can vary. It is also possible to use a linear movement device in place of the swivel device to release the coupling on the one hand and to represent a clearance between a traction means and a driver means on the other hand. Additionally, Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
         
           
               1  Actuator 
               2  Electrical engine 
               3  Reduction gear 
               4  Disconnecting device 
               5  Gear element (gear ring) 
               6  Peripheral side 
               7  upling means 
               8  Counter-coupling means 
               9  Planetary gear 
               10  Bowden control cable 
               11  Traction lever 
               12  Coupling insertion spring 
               13  Expansion mandrel 
               14  Base 
               15  Swivel joint 
               16  Housing 
               17  Ring 
               18  Coupling shaft 
               19  Swivel axis 
               20  Sun gear 
               21  Planet gear 
               22  Shaft 
               23  Swivel device 
               24  Supporting means 
               25  Planet carrier 
               26  Support 
               27  Traction rope 
               28  Drive lever 
               29  Clearance 
               30  Actuating mean 
               31  Free movement device 
               32  Supporting surface 
               33  Reset spring