Abstract:
The invention relates to a rotating catch lock, wherein a closing member ( 10 ) interacts with a catch ( 20 ), which can be rotated between a closing position accommodating the closing member ( 10 ) and an open position which releases said member. The catch ( 20 ) is force-loaded ( 22 ) in an open position and is held by a spring-loaded ( 33 ) rotating latch ( 30 ) in the close position. Said latch ( 30 ) is moved by a motor ( 50 ) between the locking position retaining the catch ( 20 ) and a stand-by release position in which the spring-loaded latch ( 30 ) is propped up by the catch ( 20 ) as long as it remains in an open position. In order to use small compact motors ( 50 ), the invention provides that the stored energy ( 61 ) exerted by an energy storage mechanism ( 60 ) is transmitted to the latch ( 30 ) via a storage lever ( 40 ). Normally, the latch ( 30 ) is shifted into its stand-by position by the storage lever ( 40 ). When the latch ( 30 ) is in a stand-by position, the storage lever ( 40 ) is supported on a control tappet ( 51 ) which is rotationally driven by the motor ( 50 ). The motor ( 50 ) can be driven by an electrical control logic in both a forward mode ( 56 ) unloading the energy storage ( 60 ) and a reverse mode (56′) loading the energy storage ( 60 ), i.e. in opposite directions. In the reverse mode (56′) the control tappet ( 51 ) releases the latch ( 30 ), moves towards the storage lever ( 40 ) and guides it back into a starting position which corresponds to the stand-by position of the latch ( 30 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to a rotary catch lock of the general type indicated in the following. After being rotated into its end position, that is, its closed position, the rotary catch accepts a closing element; this closed position is maintained by a spring-loaded, pivoting latch. In this situation, the latch is in its locking position. When the latch is moved into a release position to release the rotary catch, the rotary catch can then be moved by a restoring force back into its other rotational end position, namely, the open position, where it releases the closing element. As the catch moves into this open position, the spring-loaded latch is moved into a stand-by position, in which it rests against the open rotary catch. The latch is thus ready to move back into its locking position or pre-catch position with respect to the rotary catch when the rotary catch is rotated back into its closed position or into a previous pre-catch position. A motor and an energy storage mechanism are used to move the latch from one position to the other. Provided that the user has been granted access, the motor starts to operate as soon as the handle belonging to the rotary catch lock is operated. 
     2. Description of the Related Art 
     In the known rotary catch lock (DE 4,221,671 A1), the motor serves only to move the latch from its locking position, in which it holds the rotary catch, to a release position, in which it releases the rotary catch, whereas an energy storage mechanism, which serves as a restoring spring to return the driver which serves to move the latch, is used to move the latch into a stand-by position in preparation for the future locking position. In the known lock, the energy storage mechanism discharges its energy while the rotary catch is in its release position and thus moves the driver back into a starting position corresponding to the locking position of the rotary catch, whereas the latch initially remains in its stand-by position with respect to the rotary catch, which is still in the open position. 
     The disadvantage of the known rotary catch lock is the relatively large amount of power required to operate the motor. The motor must consume energy not only to shift the positions of the latch and the associated working elements, i.e., to move them from the locking position to the release position, but also to load the energy storage mechanism, so that, after the motor has been turned off, the mechanism has enough energy to move the driver that controls the latch back into its starting position. When the known rotary catch lock is used in a motor vehicle and the vehicle is involved in a crash, the various components of the lock are deformed, and thus more energy is required to move the latch from the locking position to the release position; if the motor is not powerful enough, it will be unable to operate the rotary catch lock, and the occupants will be trapped in the vehicle. The known rotary catch locks require powerful motors, which are not only expensive but also very bulky. This is a problem because of the limited amount of room available in the area of a rotary catch lock. 
     SUMMARY OF THE INVENTION 
     The invention is based on the task of developing a reliable rotary catch lock of the aforementioned general type which can be operated by a low-power motor and which remains functional even after a crash. This is achieved according to the invention in that the energy storage mechanism acts on a pivoting lever (storage lever), which transfers the stored energy to the latch in order to pivot it into its release position, this energy transmission occurring at least during the final phase of the pivoting motion of the latch under the action of the energy being unloaded from the energy storage mechanism; whereas, while the latch is in the stand-by position and during the initial phase of the pivoting motion of the storage lever, the storage lever rests against a tappet, which is driven rotationally by the motor; and in that the motor can be driven by electronic control logic in either direction of rotation to either of two end positions; that is, either in the forward direction to allow the energy stored in the energy storage mechanism to be unloaded, during which the tappet follows or supports the pivoting motion of the latch under the action of the storage lever, or in reverse to reload the energy storage mechanism, during which the tappet releases the latch, moves toward the storage lever, and moves it into a starting position corresponding to the stand-by position of the latch. 
     First, the invention shifts the loading of the energy storage mechanism by the motor into a time phase different from the reversing movement by which the latch leaves its blocking position and returns to its release position with respect to the rotary catch. The latch is returned while the motor is operating in the forward direction, whereas the energy storage mechanism is now loaded while the motor is operating in reverse. The energies required for these two measures are therefore not additive but separate, and this makes it possible to use low-power motors. Such motors are inexpensive and space-saving. 
     In addition, the energy storage mechanism acts on a special pivoting lever, which, while the energy storage mechanism is being loaded during the reverse operation of the motor, is moved by a tappet into a starting position which corresponds to the stand-by position of the latch. Because the energy storage mechanism is being loaded during this movement, this lever is referred to in brief below as the “storage lever”. While the motor is in forward drive, the tappet normally acts only with a braking action during the initial phase of the pivoting motion of the storage lever, i.e., in the phase before the storage lever strikes an adjusting arm belonging to the latch. In this second phase, the energy being released by the unloading of the energy storage mechanism can be used to help move the latch. In a special case, which can be the result of a crash, for example, the tappet pushes against an adjusting arm provided on the latch and thus helps to shift the latch out of its locking position into its release position. In cases such as this where the components cannot move easily, two different energy sources are therefore available: first, the energy of the loaded energy storage mechanism, which is being released by way of the storage lever, and, second, and energy of the motor operating in the forward direction, which acts directly on the latch by way of the tappet. Thus the energies supplied by the motor in two different phases of its operation can be utilized simultaneously to move the latch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Additional measures and advantages of the invention can be derived from the claims, from the following description, and from the drawings. The invention is explained in greater detail below with reference to the drawings, which show an exemplary embodiment and a suggested alternative: 
     FIG. 1 shows a top view of the catch lock according to the invention while the latch is in a blocking position, in which it holds the rotary catch in its closed position; 
     FIGS. 2-4 show the various other positions of the latch and the working positions of the rotary catch up to and including its open position on the basis of the most essential components of the catch lock shown in FIG. 1; the other components shown in FIG. 1 would have to be added here for the sake of completeness; 
     FIGS. 5 and 6 show the return motion of the essential components of the rotary catch lock leading to the stand-by position of the spring-loaded latch on the rotary catch, which is still in its open position; 
     FIG. 7 shows an operating position of the lock according to the invention comparable to that of FIG. 2 except that a crash or the like has made it difficult for the latch to move; 
     FIGS. 8 and 9 show two additional working positions of the components in the special situation of FIG. 7; FIG. 9 shows the positions and locations of the latch and the catch for the special case in comparison with those of normal operations shown in FIGS. 4 and 5; 
     FIG. 10 shows a schematic circuit diagram of some of the electrical components of the lock shown in FIGS. 1-9; and 
     FIG. 11 shows a control diagram of the electrical circuit shown in FIG. 10, from which it is possible to derive the changes in voltage over time and their relationships as established by circuit logic. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The rotary catch lock comprises a closing element  10 , designed here as a bolt, which is attached permanently to a stationary door post of a motor vehicle body and which is emphasized by shading in the figures for the sake of clarity. The other components of the rotary catch lock are installed in a housing  11  of a movable motor vehicle door, to which a rotary catch  20  in particular belongs. Rotary catch  20  can be rotated between two end positions, one of which is shown in FIG. 1, the other in FIG.  6 . In between these two end positions there are several other important intermediate positions, which are shown in FIGS. 2-4. The rotary catch is seated on an axle  21  and is subject to a restoring force acting upon it, which can arise in various ways and which is illustrated by a force arrow  22  in the figures. Restoring force  22  tries to rotate rotary catch  20  into the rotational end position shown in FIG. 6, where it is held in a defined position by a stop  12 . 
     The rotary catch has a shaped radial cutout  23 , into which, when the vehicle door is closed in the direction of the closing motion arrow  13  shown in FIG. 6, the closing element  10  enters and holds the catch  20  in the rotational end position shown in FIG.  1 . The motor vehicle door is now shut, for which reason the position of the rotary catch  20  shown in FIG. 1 is referred to as the “closed position”. When the rotary catch  20  rotates to the other rotational end position, which is suggested in dash-dot line in FIG. 4, the closing element  10  is released, and it is possible for relative motion to occur between the closing element and the door in the direction of the motion arrow  13 ′ shown in FIG.  4 . The closing element is now free and can be moved from the closed position  10  in the cutout  23  of rotary catch  20  into its release position  10 ′. Thus the rotational end position of the catch  20  shown in FIGS. 5 and 6 is called the “open position”. 
     Another component of the lock is a latch  30 , designed here with two arms  31 ,  32 ; it is mounted in a pivoting manner on an axle  34  in housing  11 . One arm  31  of latch  30  cooperates with rotary catch  20  and is therefore referred to as the “working arm”, whereas the other arm  32  is used to adjust the various positions of the latch  30  and is therefore referred to below as the “adjusting arm”. Latch  30 , as can be seen from the force arrow  33  of FIG. 1, is acted on by a spring, which tries to push the working arm  31  elastically against the rotary catch  20 . In the closed position of FIG. 1, the working arm  31  of the latch engages with a first flank  24  of the rotary catch  20  and thus holds it against its restoring force  22 . In FIG. 1, latch  30  is therefore in a position in which it effectively blocks any movement, for which reason this is referred to in brief below as the “blocking position”. 
     This flank  24  is produced by providing the previously mentioned radial cutout  23  for the closing element  10  with a suitable shape. In the exemplary embodiment shown, a similar retaining effect would also be obtained in an intermediate position of the rotary catch, which can also be seen in FIG. 3, if the working arm  31  of the latch  30 , in contrast to what is shown in the diagram, were able, after it had been released, to engage with another flank  25  of the rotary catch  20  set back even farther, as illustrated in dotted line in FIG.  3 . In this case, closing element  10  would again be caught in the radial cutout  23  of rotary catch  20 . The rotary catch  20  would now be in a “pre-catch position”. Thus, the previously described flank  24 , which performs its function when the rotary catch  20  is in the completely closed position as shown in FIG. 1, is called the “main catch flank”. It is obvious that it would also be possible to define yet other intermediate positions of the rotary catch by providing additional flanks of appropriate design on the rotary catch  20 , against which the working arm  31  of the latch would fall with a blocking action in order to secure the catch  20  in the rotational position reached at that point. 
     A direct-current motor  50 , which serves to rotate a tappet  51  by way of a set of gears  52 ,  53 , is also provided in the lock housing  11 . In the present case, a worm  52  is mounted on the motor shaft; this gear engages with a worm wheel  53 . Motor  50  is connected via a central control  14  to a control logic circuit (not shown in detail) by its two lines designated  54  and  55  in the schematic circuit diagram of FIG. 10; the way in which the logic circuit works will be explained again in greater detail on the basis of the control program of FIG.  11 . There are two additional electrical components  15 ,  16  (sensors) in the housing  11 , which are also connected via central connector  14  by lines  17 - 19  shown in the circuit diagram of FIG.  10 . These components also cooperate with the control logic and consist of sensors  15 ,  16 , which, in the present case, are microswitches. Because one sensor  15  cooperates with the catch  20 , it is referred to in brief below as the “catch sensor”, whereas the other sensor  16  is referred to analogously as the “lever sensor”, because it cooperates with a lever  40 , which will be fully described below. 
     Lever  40  is mounted on the same axle  40  as latch  30  and is thus acted on by energy storage mechanism  60 . The storage mechanism  60  exerts a stored force acting in the direction of arrow  61  of FIG. 1 on the lever  40 , for which reason this is referred to in brief as the “storage lever”. In the embodiment illustrated here, the energy storage mechanism  60  is designed as a compression spring, one end  62  of which is supported permanently in housing  11 , whereas the other end of the spring is free to act on storage lever  40 . In the closed position of the rotary catch of FIG. 1, the storage lever rests against the tappet  51 , for which reason the force  61  of the loaded energy storage mechanism  60  acting on it cannot be unloaded. When the energy storage mechanism  60  is under maximum load, the storage lever  40  is in its end pivot position. 
     If we assume the closed position of the rotary catch shown in FIG. 1, in which the motor vehicle door is closed, then, to open the door, a handle (not shown) must be operated. This can be done either mechanically or preferably electrically, as in the present case. This handle is integrated into the previously mentioned control logic circuitry. A handle such as this can be switched by electric or mechanical means between a functional state and an nonfunctional state. In the case of a lock cylinder, for example, this can be done from the outside of the door by turning a key or from the inside of the door by actuating a locking bar, the components in the lock cylinder being moved between a so-called “secured” position and an “unsecured” position or even a so-called “super-secured” position. This principle could also be used in the present rotary catch lock. But there are also other possibilities, e.g., electronic means, which the user must use to prove that he/she is “authorized” to open the vehicle door. Once the user has proven his/her right to access, the handle can be made functional mechanically or, as previously stated, electronically. The handle can now be operated successfully and, as will be explained in greater detail on the basis of FIG. 11, the motor  50 , which is initially at rest, will start to operate in forward drive, as illustrated by the motion arrow  56 . 
     As indicated by the circuit shown in FIG. 10, only five pins are needed for electrical control; these pins are represented by the previously mentioned lines  54 ,  55 , and  17 - 19 . FIG. 11 shows, as a function of time, the electrical drives at four of these pins  54 ,  55 ,  17 ,  19  along the time axis t shown in the drawing. The fifth pin  18  is not shown in the control program of FIG. 11, because, as FIG. 10 shows, it is under a negative voltage at all times. The curve  45  at the top is the control curve of the handle. The operation of the handle acts on the control logic. 
     In FIG. 11, the handle is operated at time t, which generates a pulse  46 , clearly marked on the course of curve  45 , the length of which depends on the duration of operation. At t 0 , the control logic responds to the start of the pulse triggered by the handle and reverses the potential of pin  54 , which had been negative until then, as indicated in FIG. 11, to positive at time t 1 . The time difference between t 0  and t 1  is only a few microseconds. This reversing effect which the handle, as represented by control curve  45 , exerts on pin  54  via the control logic is illustrated in FIG. 11 by an action arrow  47 . 
     At time t 1 , as shown in FIG. 11, the two pins  54 ,  55  are now at different potentials, because the other pin  55  of the motor  50  remains at a negative potential. As a result, the motor  50  starts to operate, and the forward driving  56  already mentioned in connection with FIGS. 1 and 2 begins. During this forward motion  56 , the tappet  51 , as can be seen in FIGS. 1 and 2, slides along the inside edge of the storage lever  40 , which is provided with a suitable control section  41 . This control section  41  has a beginning portion which is circular and conforms to the rotational path of the tappet  51  on the worm wheel  53 ; for this reason, the storage lever  40  does not move at first even though the stored force  61  is acting upon it. As the forward motion  56  continues, however, tappet  51  arrives at areas of the control section  41  which extend in a more nearly radial direction, for which reason the stored energy  61  can now be used to pivot the storage lever  40  increasingly in the direction of arrow  43  and thus toward the third working arm  31 . 
     In the closed position of the rotating catch  20  of FIG. 1, the lever sensor  16  is in the position shown in FIG. 10, i.e., the position in which the electrical contacts are disconnected. This means that microswitch  16  is open. In the exemplary embodiment of FIG. 1, it is the outside edge  42  of the storage lever  40  opposite control section  41  which takes care of doing this. Alternatively, this could also be done by a control projection  57  provided on the worm wheel  53 , as indicated in dash-dot line in FIG. 1; in the starting rotational position, this control projection keeps the actuating element on lever sensor  16  pushed in. The position of the switch of the lever sensor  16  can be determined by the motor drive acting through the worm gear  53  with a very high degree of precision. The starting rotational position of worm wheel  53  can also be determined by a stationary rotation stop  58  in the lock housing  11 , against which a radial finger  59  projecting from on worm wheel  53  can strike. This stop action at  58 ,  59  is not absolutely necessary, however. It would also be possible to provide a space here, as it would be in the normal case, which avoids the creation of noise during the control movements of the components. As FIG. 11 shows, the two pins  54 ,  55  of the motor are at the same negative level in the period of time before t 0 ; the electrical lines of the motor are short-circuited, for which reason the motor does not turn. 
     The pivoting motion  43  of the storage lever  40  comes about as a result of the unloading of the energy storage mechanism  60 , whereas the tappet  51  controls this pivoting motion  43  only in a “braking” manner as it is driven forward  56 . FIG. 2 shows that, during this pivoting motion  43 , the actuating element of the lever sensor  16  will ultimately be released, which is shown in FIG. 11 to occur at time t 2 . Pin  17  of the circuit in FIG. 10, which up until now has been at a positive potential, arrives at the negative level of pin  18 , which now leads to further effects. 
     In FIG. 2, contact has occurred at point  35  between the two parts  30  and  40 . Whereas up to now the tappet  51  has prevented the stored energy  61  of energy storage mechanism  60 , which acts on control lever  40 , from acting on the latch  30  as well, the stored energy  61  is now transferred via contact point  35  to the working arm  31  of the latch, and the adjusting arm  32  is thus pivoted in the direction of the pivot arrow  36  shown in FIG.  3 . This means that the working arm  31  of the latch, which until now has been resting against the main catch flank  24  of the rotary catch  20 , becomes gradually disengaged. Disengagement has just occurred in the pivot position of the latch  30  shown in FIG. 3; the working arm  31  of the latch  30  has released the catch, for which reason the catch is now able to rotate further in the direction of its open position of FIG.  5 . In FIG. 3, the actuating element of the catch sensor  15  is still being pressed in by a suitable rotary catch control section  26 , and therefore the contacts of the sensor are still being held in the open position, as indicated in FIG. 10; that is, a positive potential is present at pin  19  of the circuit of FIG. 10, as can be seen from the curve at the bottom of the control diagram of FIG.  11 . This action of the control section  26  was also present, of course, in the preceding illustrations of FIGS. 1 and 2. 
     This situation does not change until the limit position is reached, shown in solid line in FIG.  4 . The rotary catch  20  has now turned to such an extent under the action of its restoring force  22  that the actuating element of the catch sensor  15  is released by the associated control section  26 . The closing of the contact of the catch sensor  16  in FIG. 10 puts pin  19  at the negative potential of pin  18 , which corresponds to time t 3  in the control program of FIG.  11 . In FIG. 4, the latch  30  has already arrived in its end pivot position under the action of the stored energy  61 , for which reason the latch  30  and the storage lever  40  remain at rest for the time being. Up until time t 3 , the tappet  51  has been rotating in the direction of arrow  56  and has thus broken contact with the storage lever  40 . 
     The control logic of the rotary catch lock responds to the reversal of the catch sensor  15  at time t 3  of FIG. 11 and, after a short reaction time, namely, at time t 4  of FIG. 11, puts the two pins  54 ,  55  of the motor  50  at mirror-image potentials. This is indicated by the two action arrows  48  of FIG.  11 . Thus pin  54  is switched to a negative potential and pin  55  to a positive potential. This has the result that the motor  50 , which up to now has been driving forward, brakes as a result of the opposite voltages. This change occurs at the rotational position which the tappet  51  has just reached in FIG.  4 . At this point, however, the motor starts to rotate in the opposite direction, so that now the motor begins to drive in reverse and thus the tappet  51  also starts to moves backwards, as indicated by rotation arrow  56 ′ in FIGS. 4 and 5. In the meantime, the restoring force  22  acting on the rotary catch  20  rotates the catch to its fully open position, illustrated in dash-dot line in FIG. 4, which allows the door of the vehicle to be opened. Closing element  10  can leave its radial cutout  23  in the catch  20 ; the opening movement illustrated by the arrow  13 ′ in FIG. 4 occurs, which allows the closing element to reach its release position  10 ′. 
     With the vehicle door open, the rotary catch  20  in FIG. 5 is still in the open position, which is determined by the previously mentioned stop  12 . During this time, however, the motor has continued to move tappet  51  backwards in direction  56 ′. The tappet  51  meets the control section  41  of the storage lever  40  again and pivots the lever back in the direction of pivot arrow  43 ′ of FIG.  5 . As a result, the motor works in the direction opposite that of the stored energy  61 , and the loading of the energy storage mechanism  60  begins. The motor  50 , however, does not need to perform any other work during this reverse driving  56 ′, for which reason all of the motor&#39;s energy can be used to load the energy storage mechanism  60 . The latch  30  remains at rest, even though the previously mentioned spring force  33  is acting on it, as also shown in FIG.  5 . This reason for this is that the working arm  31  of the latch has a locking tooth  37 , which rests against the previously mentioned control section  26  of the rotary catch  20 . The spring force  33  exerted by the latch  30  therefore presses the locking tooth  37  elastically against the control surface  26 . The spring-loaded latch is thus now in its “stand-by position” as shown in FIG.  5  and also in FIG.  6 . Even though its locking tooth  37  wants to pass radially into the appropriate flank of the rotary catch  20 , it is initially prevented from doing so at this point by the control section  26  on the catch. 
     In FIG. 6, the reverse motion  56 ′ of the tappet  51  has pushed storage lever  40  back into its starting position as shown in FIG.  1 . As a result, the actuating element on the associated lever sensor  16  is actuated. As already mentioned in conjunction with FIG. 1, the outside edge  42  of the storage lever accomplishes this actuation in the exemplary embodiment; alternatively, however, it would also be possible to use a control projection  57  seated nonrotatably on the worm wheel  53 . When lever sensor  16  is actuated, its contacts open again, as can be seen in FIG.  10 . The connection to pin  18  is interrupted, and pin  17 , as can be seen at time t 5  in the next-to-last curve, is again at a positive potential. This change in voltage is evaluated by the control logic, and after a short reaction time, the potential at pin  55  of motor  50  also changes, namely, at time t 6  of FIG.  11 . This effect of the control logic is illustrated in FIG. 11 by an action arrow  49 . Pin  55  thus assumes a negative potential, as shown by the control program of FIG.  11 . The two pins  54 ,  55  belonging to the motor  50  therefore again have the same potential, namely, a negative one, for which reason the motor  50  is short-circuited and brakes. The motor thus comes to an exact stop without any need for the action of mechanical end stops. 
     FIG. 6 shows an end situation of this type with the door open. The energy storage mechanism  60  is now fully loaded again, so the maximum amount of stored energy  61  is available. While storage lever  40  is in its starting position, which is also present when the door is closed, the latch  30  is in its previously described stand-by position as long as the closing element is in its release position  10 ′ outside the rotary catch  20 . If, while the door remains open, the handle is actuated again by mistake, the control logic ensures that the motor  50  remains idle. The control logic detects this on the basis of the fact that the catch sensor  15  of the catch  20  has not been actuated. 
     As FIG. 6 illustrates, the spring force  33  acting on the latch  30  can be achieved by means of a spring element  27 , which acts between the latch  30  and the storage lever  40 . A two-shank torsion spring can be used for this, which is attached to the common axle  34  of the latch  30  and the storage lever  40  and which, with its two shanks  28 ,  29 , tries to push the working arm  31  of the latch and the storage lever  40  toward each other. The two components  40 ,  31  are prevented from approaching each other, however, because the storage lever  40  rests against the tappet  51  and the latch  30  rests against the control section  26  on the catch. Of course, the latch  32  could obtain the elastic force  33  described above from its own spring. The energy storage mechanism  60  acting on the storage lever  40  is indicated only schematically in the drawings; in an actual case, it could consist of a two-shank spring, one end of which is supported against the housing, while the other end transfers the stored energy  61 . 
     This latter situation does not change until the door is to be closed, which means that the closing element  10 ′ now moves in the direction of closing motion arrow  13  of FIG.  6  and pushes against the flank  24  in the radial cutout  23  in the rotary catch  20 . The closing element thus rotates the catch back again against the restoring force  22 . As a function of the extent to which the catch is rotated, the latch  30 , which is in its stand-by position, can now engage either with flank  25  of the pre-catch or with flank  24  of the main catch and thus arrive in either the previously mentioned pre-catch position or the final closing position shown in FIG.  1 . Thus the working cycle is completed. 
     As can be derived from FIGS. 1-6, the tappet  51  moves back and forth in the space, designated  44  in FIG. 6, between the storage lever  40  and the latch adjusting arm  32  during the forward and reverse driving  56 ,  56 ′ of the motor. Thus, during forward driving  56 , there is only a passive adjusting movement of the tappet  51  on storage lever  40  and no interaction between the tappet  51  and the latch  30 . There is active interaction between the tappet  51  and the control section  41  on the storage lever only during the reverse pivoting motion  43 ′ illustrated in FIG.  5 . This applies, however, only to the normal case described in FIGS. 1-6 and not to the special case now to be explained on the basis of FIGS. 7-9. 
     The special case shown in FIG. 7 represents a rotational position of the rotary catch which corresponds to the relationships of the normal case described in FIG.  2 . The only difference is that it is now difficult for the latch adjusting arm  32  to execute its pivoting motion  36 , which could be the result of a crash, for example, in which the motor vehicle was involved. The friction between the locking tooth  37  of the latch  30  and the flank  24  in the cutout  23  of the catch  20  is so great that the stored energy  61  acting on the storage lever  40  described in conjunction with FIG. 2 is not strong enough to disengage the latch  30  from the rotary catch  20  by way of the contact point  35 . Even if, in spite of the opening forces  22 ,  61  acting upon them, the components  20 ,  40 , and  30  are initially immobile in this special case, the motor can still continue to move the tappet  51  in the intermediate space  44 . It can be seen in FIG. 7 that, as a result of its forward movement  56 , the tappet  51  has left the storage lever  40  and is now approaching the latch adjusting arm  32 . 
     In FIG. 8, a limit situation has just been reached in which the continued forward movement  56  of the tappet  51  has led to contact between the tappet and the control section  39  on the inside edge of the latch adjusting arm  32 . The tappet then proceeds along this edge, as can be seen in FIG.  9 . As this rotational movement  56  continues, the tappet  51  exerts an additional opening force  63 , shown in FIG. 8, which is added to the stored energy  61  exerted by the storage lever  40  via the contact point  35 . The energy now available, which is practically double the original amount, is sufficient to overcome the jamming of the components and to bring about the desired pivoting motion  36  of the latch  30 . 
     This successful result is illustrated in FIG.  9 . The working arm  31  of the latch has left the original position of the rotary catch illustrated in dash-dot line and has arrived under the action of its restoring force  22  in its open position, shown in solid line. The closing element can now be moved into its release position  10 ′. 
     FIG. 9 illustrates relationships which are similar to those of the normal case presented in FIG.  4 . The agreement consists namely in that, in both FIGS. 9 and 4, the actuating element of the catch sensor  15  has been released and that therefore at this point the motor begins to operate in reverse, with backward rotation  56 , as already described in conjunction with FIG. 5. A comparison, however, shows that, in the special case of FIG. 9, the motor has driven the worm wheel  53  forward over a much greater angular range  64  than in the situation of FIG. 4 corresponding to the normal case. This angle  64  means that a correspondingly greater amount of energy has been consumed by the motor  50  to open the difficult-to-move rotary catch  20  in the special case. A comparison of FIGS. 4 and 9 also shows that, in the special case of FIG. 9, the energy storage mechanism  60  has also been unloaded to a much greater extent and that therefore additional stored energy  61  has also been supplied to open the rotary catch  20 . All this is possible while making only modest demands on the energy to be supplied by the motor  50 ; the motor can therefore have a low power rating and will thus occupy only a modest amount of space. 
     The end position of the forward driving  56  of the tappet  51  shown in FIG. 9 can also be defined by the action of an additional rotation stop  38 . The finger  59  on worm wheel  53 , already mentioned in conjunction with FIG. 1, has made contact with its rotation stop  38  and thus stops the motor  50  from turning under any possible circumstances. As a support measure, the control logic can also respond to this stop situation, which it detects by electrical means, i.e., from the increase in the amount of power drawn by the motor after contact has been made with the stop. At this point, the motor  50  will always begin to operate in reverse, and thus the tappet  51  will also begin its reverse operation  56 ′, as previously described in conjunction with FIGS. 4 and 5; in this special case, too, the tappet ultimately brings the latch  30  into the stand-by position of FIG. 6 with the rotary catch  20  in the open position, in the same way as in the normal case. As this is happening, the energy storage mechanism  60  becomes loaded again. In the special case of FIG. 9, the angular range around which this charging occurs is larger than that of the reverse driving  56 ′ described in FIG.  5 . 
     LIST OF REFERENCE NUMBERS 
       10  closing element (while being held in  20 ) 
       10 ′ release position of  10   
       11  lock housing 
       12  stop for  20   
       13  arrow of the closing motion between  10 ′ and  10   
       13 ′ arrow of the opening motion between  10  and  10 ′ 
       14  central plug at  11   
       15  first sensor, catch sensor 
       16  second sensor, lever sensor 
       17  line from  15 , pin 
       18  line from  15  and  16 , pin 
       19  line from  16 , pin 
       20  rotary catch 
       21  axle of  20   
       22  arrow of the restoring force acting on  20   
       23  radial cutout in  20 , receptacle for  10   
       24  flank in  23 , main catch 
       25  pre-catch flank on  20   
       26  control section on  20  for  15  and  37   
       27  spring element between  30  and  40   
       28  first shank of  27   
       29  second shank of  27   
       30  latch 
       31  working arm of  30   
       32  adjusting arm of  30   
       33  arrow of the spring force acting on  30   
       34  axle for  30  and  40   
       35  contact point between  31  and  40   
       36  arrow of the pivoting motion of  31   
       37  locking tooth on  31   
       38  second rotation stop for  59  (FIG. 9) 
       39  control section on  32  (FIGS. 8,  9 ) 
       40  storage lever 
       41  control section on  40   
       42  outside edge of  40   
       43  arrow of the pivoting motion of  40   
       43 ′ arrow of the reverse pivoting motion of  40   
       44  intermediate space between  32  and  40   
       45  course of the voltage curve upon operation of the handle (FIG. 11) 
       46  pulse upon operation of the handle (FIG. 11) 
       47  action arrow between  45  and  54  at t 0 /t 1  (FIG. 11) 
       48  two action arrows between  19 / 54  and  19 / 55  at t 3 /t 4   
       49  action arrow between  17 / 55  at t 5 /t 6   
       50  direct-current motor 
       51  tappet 
       52  gear component, worm 
       53  gear component, worm wheel 
       54  first line of  50 , pin 
       55  second line of  50 , pin 
       56  arrow of the forward driving of  51   
       56 ′ arrow of the reverse driving of  51   
       57  alternative control projection on  53   
       58  first rotation stop for  59   
       59  finger on  53   
       60  energy storage mechanism 
       61  stored energy of  60   
       62  stationary end of spring  60   
       63  motor-generated opening force at  32  (FIG. 8) 
       64  angular range of the further rotation of  51  in the special case (FIG. 9) 
     t time axis 
     t 0  time at which handle is operated 
     t 1  time at which forward driving  56  of  50  begins 
     t 2  time at which  16  closes 
     t 3  time at which  15  closes 
     t 4  time at which reverse driving  56  of  50  begins 
     t 5  time at which  16  opens 
     t 6  time at which reverse driving  56  of  50  ends