Abstract:
The apparatus ( 2 ) for vibrationproof locking of a plug ( 3 ) in its plugged-in position inside a unit, in particular inside a clutch actuator ( 1 ), encompasses a housing ( 4 ) that has a housing top shell ( 16 ) and a housing bottom shell ( 6 ), by means of at least one locking element ( 30 ) that engages the plug ( 3 ). The locking element ( 30 ) has a blocking section ( 52 ), which is kept in a blocking position by the plug ( 3 ) when this plug is not completely plugged in—thus preventing the housing shells ( 6 ) from being joined—and which can be brought into a position that permits the housing shells ( 6 ) to be joined only when the plug ( 3 ) is completely plugged in.

Description:
BACKGROUND OF THE INVENTION 
     The invention is based on an apparatus for vibrationproof locking of a plug in its plugged-in position inside a unit, in particular inside a clutch actuator, with a housing that has at least two housing shells. 
     A known clutch actuator for engaging and disengaging a vehicle clutch according to DE 197 01 739 A1 is integrated into a dual-shelled housing, which is comprised of a housing bottom shell and a housing top shell, which can be pivoted in relation to each other around a pivot axis so that two flanges formed onto each housing shell rest against each other with a seal between them. The housing bottom shell contains an electric motor for driving a tappet that is connected to a piston of a hydraulic master cylinder. In order to supply power to the electric motor, electrical plug connections are required, that are produced, for example, by plug connectors that are disposed at the end of power cables and are plugged into associated sockets or plugging locations on the electric motor. 
     Clutch actuators of this kind are subjected to vehicular vibrations, which leads to the problem of the plugs coming loose over time due to the vibration. As a result, plugs that are subjected to vibrations are often secured with additional locking elements such as screw connections, pin connections, clips, or the like, which are intended to secure the plug in the plugged-in position. Locking elements of this kind, however, usually do not prevent the plug from being plugged in incompletely or in a tilted fashion, which brings the danger of an electrical contact not being produced or only being produced to an insufficient degree. 
     SUMMARY OF THE INVENTION 
     The apparatus according to the invention for vibrationproof locking of a plus in its plugged-in position, has the advantage that a further assembly of the unit is prevented if the plug is not in its final plugged-in position so that a correction installation of the plug is assured every time. In addition, no additional parts are required since the blocking section of the locking element that is already provide performs the blocking function. 
     A particularly preferable modification of the invention provides that only after the plug is completely plugged in is a section of the plug flush with an associated section of the locking element and only then can the locking element be moved in relation to the housing into a locking position in which the section of the plug is overlapped by the associated section of the locking element in order to secure the plug in the plugged-in position. Since a locking is only possible in a correct plugged position, incorrect plugged positions of the plug become immediately apparent. 
     Another preferable measure provides that the locking element is held in the locking position by the housing top shell that is placed onto the housing bottom shell. Since the mounted housing top shell prevents an unlocking, the locking of the plug is self-securing and cannot unintentionally come loose, which is particularly advantageous in plug connections that are subjected to vibration. 
     According to one modification, the blocking section simultaneously serves as a grasping section for actuating the locking element and is flat in design. This achieves an advantageous functional combination because it saves space. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are shown in the drawings and will be explained in detail in the subsequent description. 
     FIG. 1 is a top view of a housing bottom shell of a clutch actuator, into which an exemplary embodiment of an apparatus according to the invention for vibrationproof locking of a plug is integrated; 
     FIG. 2 shows an enlarged sectional depiction along the line II—II of FIG. 1; 
     FIG. 3 shows a cross section through the clutch actuator from FIG. 1, in which the apparatus according to the invention is disposed in an unlocked position; 
     FIG. 4 shows a cross section through the clutch actuator from FIG. 1, in which the apparatus according to the invention is disposed in a locked position 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The clutch actuator  1  shown in FIG. 1, which is for engaging and disengaging a vehicle clutch, has an exemplary embodiment of an apparatus  2  for vibrationproof locking of a plug  3  in its plugged-in position integrated into it. The clutch actuator  1  is comprised of a dual-shelled housing  4 , of which only a housing bottom shell  6  is shown in the top view FIG. 1, which contains an electric motor  8  with a crank mechanism  10  and a tappet  12 , which is connected to a hydraulic master cylinder  14 . The housing bottom shell  6  and the housing top shell  16 , a cross section of which is depicted in FIGS. 3 and 4, each have an outer flange  18  formed onto them on which eyes  20  with through bores or threaded bores are embodied in order to be able to screw the two housing shells  6 ,  16  to each other with a seal between them. The function of a clutch actuator  1  of this kind is known to a sufficient degree from DE 197 01 739 A1 and therefore requires no further explanation. 
     In order to be supplied with power, the electric motor  8  has a connecting block  22  connected to it, with sockets into which plugs  26  connected to the ends of electrical lines  24  are plugged (FIG.  1 ). For vibrationproof locking of one of the plugs  3 , a locking element is provided in the housing bottom shell  6  and can be guided, for example, by means of a linear guide  28 ; in the preferred embodiment, this locking element is a slider  30 . The linear guide  28  of the slider  30  is produced by virtue of the fact that a pin  34 , which is disposed next to the connecting block  22 , protrudes from a wall  32  of the housing bottom shell  6 , e.g. at right angles, and engages in an oblong hole  36  of a guide section  38  of the slider  30 , which permits the slider  30  to move toward the plug  3  and away from it, preferably in a direction lateral to it. The pin  34  is secured in the oblong hole  36  of the slider  30  by a spring lock washer  40  press-fitted onto it from the outside, as best shown in the enlarged cross section in FIG.  2 . 
     FIG. 3 shows a broken lateral cross sectional view of the clutch actuator  1 , in an installation state before the joining of the two housing shells  6 ,  16 , in which the plug  3  is not completely plugged into its associated socket  22 . By contrast, FIG. 4 shows the correctly installed position after the joining of the two housing shells  6 ,  16 . 
     The end of the plug  3  is preferably connected to a tab  42 , which projects toward the slider  30  and whose underside facing away from a bottom of the housing bottom shell  6  has a for example horizontal locking surface  44  for a hold-down surface  46  on the underside of the guide section  38  of the slider  30 , with which it can slide along a guide surface  48  embodied on the housing bottom shell  6 . Consequently, the guide surface  48  for the slider  30  is preferably disposed in a plane with the hold-down surface  46  of the slider  30 . In the completely plugged-in position of the plug  3  according to FIG. 4, the surface of the tab  42  oriented toward the bottom of the housing bottom shell  6  rests against a stop surface  50  of the housing bottom shell  6 . The hold-down surface  46  on the slider  30  is only flush or coplanar with the locking surface  44  of the plug  3  when the plug is completely plugged in (FIG.  4 ). Only then can the slider  30  be slid toward the plug  3  and the hold-down surface  46  of the slider  30  overlap the locking surface  44  of the plug  3  in order to affix it to the connecting block  22 . 
     On the side oriented away from the plug  3 , the guide section  38  of the slider  30  is provided with a flat grasping section  52  in order to manually slide the slider  30  from the position shown in FIG. 3 in which the plug  3  is unlocked, into the position shown in FIG. 4 in which the plug  3  is locked. However, if the plug  3  is not completely plugged in, as in FIG. 3, or is plugged into the associated socket of the connecting block  22  in a tilted position, then the underside of its tab  42  is spaced apart from the stop surface  50 , as a result of which the tab  42  of the plug  3  projects beyond the guide surface  48  for the slider  30  by a distance and as a result, prevents the slider  30  from sliding toward the plug  3 . 
     With regard to its vertical span, a lower edge  54  of the grasping section  52  of the slider  30  oriented toward the bottom of the housing bottom shell  6  protrudes beyond the outer flange  18  of the housing bottom shell  6  independent of whether the locking position has been assumed or not. Moreover, the overhanging length of the grasping section  52 , the relative position of the oblong hole  36  of the slider  30 , and the length of this oblong hole  36  are selected so that in the unlocked or unlockable state of the plug  3 , the grasping section  52  protrudes laterally beyond the outer contour of the housing bottom shell  6  constituted by the outer flange  18  so that in this case, it is not possible to join the two housing shells  6 ,  16 . Consequently, the grasping section  52  simultaneously serves as a blocking section in order to prevent a further assembly of the clutch actuator  1  when the plug  3  is not completely plugged into the socket  22 . By contrast, when the plug  3  is completely plugged in as shown in FIG.  4  and is disposed in the correct operating position, the hold-down surface  46  of the slider  30  can then overlap the coplanar locking surface  44  of the plug  3  and the slider  30  can travel into the locked position. The sliding motion of the slider  30  is determined among other things by the length and relative position of the oblong hole  36 ; these parameters are selected in such a way that when the slider  30  is in the locked position, its end surface  56  preferably contacts a side surface  58  of the plug  3  and the blocking section  52  no longer overlaps the outer flange  18  of the housing bottom shell  6 . Then the blocking section  52  is disposed within the clutch actuator  1  periphery, which is predetermined by the outer contour. With regard to its vertical span, an upper edge  60  of the blocking section  52  is disposed underneath an upper wall  62  of the housing top shell  16  so that the latter can be joined to the housing bottom shell  6 . 
     When mounted in place, the housing top shell  16  prevents the slider  30  from coming out of the locked position by virtue of the fact that the distance between the free end  64  of the blocking section  52  of the slider  30  and a side wall  66  of the housing top shell  16  is shorter than the sliding distance required for the unlocking. This produces a self-securing locking of the plug  3 ; it can only be unlocked after the housing shells  6 ,  16  are disassembled. 
     The apparatus  2  according to the invention is not limited to the locking of a single plug  3 ; instead, a number of plugs  26  can be locked by simply widening the slider  30  or by using several sliders  30 .