Abstract:
An electrical plug connection is provided having a plug housing and a complimentary contact housing. A transverse slide is slidably coupled to the contact housing between a closed position and an open position. The transverse slide locks the plug housing to the contact housing in the closed position. At least one movable carriage is slidably coupled to the contact housing. At least one spring element exerts a force between the movable carriage and the transverse slide during closing of the transverse slide. The spring element pushes the transverse slide to the open position when there is an incomplete closing of the transverse slide. The transverse slide is locked in the closed position only on complete closing of the transverse slide.

Description:
FIELD OF THE INVENTION 
     The invention relates to an electrical plug connection, particularly for motor vehicle applications, with a plug housing, a contact housing complementary to the plug housing and a transverse slide for locking the plug housing in the contact housing. 
     BACKGROUND OF THE INVENTION 
     Plug connections of this kind are mainly used in a wall of a housing in order to connect to external conductors electrical connections of a device in the housing. For example, plug connections of this kind are used for pre-cabling for motor vehicle transmissions. It is particularly in the area of motor vehicle transmissions that intense vibrations occur in addition to relatively high operating temperatures and may result in the plug connections loosening or breaking away. 
     To secure the connection, known plug connections have locking devices which are intended to ensure that the plug housing is secured in the contact housing. On assembly, of course, care must be taken to ensure that the locking device really is engaged. In practice it may happen that the fitter brings the locking device only into an intermediate position in which although the plug housing has been pushed into the contact housing the locking device is not in its catch position. In that case the plug connection may automatically break away due to the high vibrations occurring in the operation of the motor vehicle. 
     The object of the invention is to provide an electrical plug connection wherein assembly faults caused by incomplete closure or engagement of the locking device are reliably avoided. 
     This problem is solved by the features of claim  1 . 
     SUMMARY OF THE INVENTION 
     The plug connection according to the invention comprises a plug housing, a contact housing complementary to the plug housing and a transverse slide for locking the plug housing in the contact housing. At least one spring element acts on at least one movable carriage, said spring element exerting an increasing stress on the slide during the closing of the latter and pushing it back into its open position in the event of an incomplete closing operation. The slide is locked in its closed position only on complete closure. 
     The co-operation of the slide, spring element and carriage according to the invention has the effect that the electrical plug connection and its locking device are always in a defined state and this state is unmistakably indicated to the fitter. If the slide is inserted only incompletely, coupling of the carriage to the slide by way of the spring element causes the latter to exert a force on the slide which, after the manual insertion force has ceased, automatically pushes it back into its open position. This indicates to the fitter that the locking device has not been engaged and hence cannot fulfil its securing function. 
     Another special feature of the invention is that on the insertion of the slide the two main parts of the plug connection, namely the plug housing fixed on a housing wall, and the contact housing, are clamped together, this being achieved by the configuration of guides in the slide to receive studs on the plug housing. 
     This leads to the advantageous possibility of making the connection between electrical contacts of the plug part and the electrical contacts of the contact part only when the slide is inserted. If the housings are simply plugged together (plug housing, contact housing) and the slide is in the open position, there is no electrical connection between the contacts. Because of the restoring force of the spring element the slide occupies two defined positions, namely the open position and the closed position. The configuration of the guide groove has the effect that the two housings are guided together on insertion of the slide and are separated on the rise of the slide. Similarly, the electrical contacts of the main parts are brought into electrical connection on the insertion and separated from one another on the rise of the slide. There is consequently a direct relationship between the position of the slide and the electrical connection of the corresponding electrical contacts. Thus in the closed position the contacts are interconnected while in the open position they are not. If current now flows through the plug connection, that simultaneously confirms that the slide is completely closed. 
     Preferred embodiments of the invention are indicated in the sub-claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     One preferred exemplified embodiment of the plug connection according to the invention is described below in detail with reference to the drawing, wherein: 
     FIG. 1 shows the main parts of a plug connection with a perspective front view of the contact housing and plug housing. 
     FIG. 2 shows a slide in the form of a yoke in perspective. 
     FIG. 3 is a perspective view of one limb of the slide of FIG. 2 without a carriage. 
     FIGS. 4 a  and  4   b  show the slide carriage in perspective in top and bottom plan view respectively. 
     FIG. 5 is an enlarged-scale perspective view of the partially sectioned limb with the carriage. 
     FIGS. 6 a - 6   c  show the contact housing with the slide in different positions and 
     FIGS. 7 a - 7   d  show the mode of operation of the exemplified embodiment of a tongue. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The electrical plug connection shown in FIG. 1 is designed as a pre-cabling for the transmission of motor vehicles and consists of a plug part I fixed in a wall opening of a vehicle part and a contact part II which can be plugged therein and which is constructed according to the invention and will be described in detail hereinafter. 
     The contact part II comprises a contact housing  1  with an annular front part  2  in which there is incorporated a disc-shaped contact insert  3  and a profiled sealing ring  4  is snapped on the outside thereof. A locking device for securing the contact housing  1  in the plug housing of the plug part I is constructed as a slide  5  in the form of a yoke with two limbs  6 ,  7 . A C-shaped yoke  9  is formed on the substantially square back part  8  of the slide  5 , and its arms  10 ,  11  extend over and parallel to the two limbs  6 ,  7  and each has at its flat inside a guide groove  12 , the arms  10 ,  11  being guided transversely of the plug axis in two parallel guides  42 ,  43  formed on the contact housing  1 . 
     As will be seen particularly from FIGS. 2 and 3, each limb  6 ,  7  has two side walls  21 ,  22  which extend in parallel in the sliding direction and which together with a partition  23  formed on one side each define an elongate recess  13 ,  14 . An axial stud  15 ,  16  is formed on the inner end wall  24  of each recess  13 ,  14  and apertures  17 ,  18  are provided on both sides in the two side walls  21 ,  22  into each of which there projects on one side a tongue  19 ,  20  with an oblique ramp surface. 
     Each limb  6 ,  7  of the slide  5  has an associated carriage  25  shown in FIGS. 4 a  and  4   b . Each carriage  25  has a substantially rectangular elongate baseplate  26 , at one end of which there is integrally formed a support plate  27  perpendicular thereto with a pin  28  extending parallel to the baseplate  26 . Parallel to both sides of the baseplate  26  there extend webs  30 ,  31  in the form of tongues which at the ends are integrally connected to the widened end part  29  of the baseplate  26 . Formed in each web  30 ,  31  is a downwardly open cut-out  32 ,  33 , which is defined at one end by an oblique surface  34 ,  35  and at the other end by a vertical surface  36 ,  37 . The undersides of the baseplate  26  and of the webs  30 ,  31  lie in one plane. 
     FIG. 5 shows one limb  6  of the slide  5  of FIG. 3 together with a built-in carriage  25  according to FIG. 4 a ,  4   b  without an expanding spring. The carriage  25  is an end position in which its support plate  27  bears against the end partition  23  of the limb  6 . The width of the carriage  25  corresponds to the width of the limb  6  so that the two tongue-shaped elastically deformable webs  30 ,  31  are situated opposite the tongues  19 ,  20  projecting into the apertures  17 ,  18 . The top of the support plate  27  is in line with the upper surfaces of the walls  21  to  24  of the limb  6 . The height of the webs  30 ,  31  of the carriage  25  is smaller than the height of the support plate  27 , so that the front zone  21   a ,  22   a  of the side walls  21 ,  22  can slide on the upper side of the webs  30 ,  31 . The width of the side walls  21 ,  22  corresponds to the width of the webs  30 ,  31 . The middle zone  21   b ,  22   b  of the side walls  21 ,  22  has the already mentioned apertures  17 ,  18  to receive the webs  30 ,  31  so that the height of the middle zone  21   b ,  22   b  turns out smaller than the height of the front zone  21   a ,  22   a . This middle zone  21   b ,  22   b  is continued by the rear zone  21   c ,  22   c  of the side walls  21 ,  22  so that the undersides of the webs  30 ,  31 , of the tongues  19 ,  20  and of the rear zone  21   c ,  22   c  of the side walls  21 ,  22  are in one plane. 
     FIGS. 6 a  to  6   c  show the back of the contact housing  1  with a slide  5  in different positions, two built-in carriages  25  and two expanding springs  40 ,  41  each disposed in a recess  13 ,  14  in the limbs  6 ,  7  and clamped between the pin  28  and the axial studs  15 ,  16 . As will be clear particularly from FIGS. 7 a  to  7   d , which illustrate a section on the line A—A included by way of example in FIG. 6 c , the upper side of the side walls  21 ,  22  of the limbs  6 ,  7  are guided by guide rails  44 ,  45  formed integrally on the contact housing  1 . 
     It will also be seen that the height of the end wall  24  turns out smaller than the height of the rear zone  21   c  of the side wall  21 , so that on actuation of the slide  5  the baseplate  26  can slide under this end wall  24 . Also formed on the back of the contact housing  1  for each cut-out  32 ,  33  of the carriage  25  is a matching catch  48  which at one end is defined by an oblique surface  49  and at the other end by a vertical surface  50 . 
     The co-operation of the slide  5  according to FIGS. 2 and 3, of the carriage  25  according to FIGS. 4 a ,  4   b , and of the contact housing II according to FIG. 1, will now be described with reference to FIGS. 6 and 7. 
     FIG. 6 a  shows the slide  5  in the open position as the fitter receives the contact housing I before insertion, while FIG. 7 a  shows the corresponding sectional drawing to FIG. 6 a . In this open position, the support plate  27  abuts the partition  23 . The catch  48  of the contact housing  1  is situated in the cut-out  33  of the web  31 . The underside of the web  31  rests on the back of the contact housing  1 . The distance between the support plate  27  and the end plate  24  is at the maximum in this state of the slide so that the expanding spring  41  situated therebetween is relieved of stress. 
     The matching plug part I (see FIG. 1) is now plugged on to the front of the contact part II. To lock the plug connection, the fitter must press the slide  5  in the direction of arrow G. In these circumstances the upper side of the side walls  21 ,  22  is guided by the guide rails  44 ,  45 . As will be clear particularly from FIG. 7 a , the underside of the front zone  21   a  of the side wall  21  slides on the upper side of the web  31 . The entire carriage  25  does not change its position, since the catch  48  holds the web  31  fast. The end wall  24  slides over the baseplate  26 . The distance between the support plate  27  and end plate  24  is reduced, i.e. the expansion spring  41  is stressed. The catch elements (not shown) of the slide  5  and of the contact housing  1  do not interlock until the slide  5  is completely pushed into the contact housing  1 , as shown in FIG. 6 b , FIG. 7 b  being the corresponding sectional drawing. The distance between the support plate  27  and the end plate  24  is then the smallest. Consequently the force acting on the end wall  24  and produced by the expanding spring  41  is at maximum. If the catch elements (not shown) are so designed as to withstand this force, the slide  5  remains in the closed position, but with the disadvantage that the expanding spring  41  is constantly stressed. To obviate this unwanted effect, the springs  41 ,  40  must be relieved of stress. 
     As will be seen particularly from FIG. 7 a , for this purpose the tongue  19  projects into the aperture. As soon as the catch elements (not shown) engage, the oblique ramp surface of the tongue  19  passes beneath the web  31  (see FIG. 7 b ). The ramp  38  of the web  31  facilitates the insertion of the tongue  19  thereunder. As a result, the web  31  is lifted over the catch  48  into the aperture  17  and is slightly elastically deformed. Since the slide  5  is connected to the contact housing  1  because of the catch elements (not shown), the expanding spring  41  can only be relieved of stress by the carriage  25  moving together with the webs  30 ,  31  in the direction of the partition  23 . After overcoming the catch  48  the web  31  again comes on to the back of the contact housing  1  because of its elastic deformation (see FIG. 7 c ). 
     It is also feasible for the force directed towards the back of the contact housing  1  to be generated by rigid webs  30 ,  31  and a flexible baseplate  26 . In that case (not shown), the support plate  27  would also be lifted and the webs  30 ,  31  would not undergo deformation. Instead the baseplate  26  would be elastically deformed. 
     After the webs  30 ,  31  have reached the back of the contact housing  1 , i.e. as shown in FIG. 7 c , they slide beneath the underside of the front zone  21   a  of the side walls  21  until the support plate  27  meets the partition  23 . The distance between the support plate  27  and the end plate  24  is now again at a maximum, i.e. the expanding spring  41  is relieved of stress. This“stress-relieved” closed position is shown both in FIG. 6 c  and in FIG. 7 d.    
     It should be noted that FIG. 7 c  shows an intermediate position of FIG. 7 b , which is the sectional view of FIG. 6 b , and of  7   d , which is the sectional view of FIG. 6 c . None of the FIGS. 6 a  to  6   c  shows the position of FIG. 7 c.    
     Of course if the slide  5  is not completely pushed in, i.e., before the catch elements (not shown) can engage, the expanding spring  41  presses the slide  5  back into its open position, since the carriage  25  is connected to the catch  48  as shown in FIG. 7 a.    
     It should also be noted that in the“unstressed” closed position the carriage  25  and support plate  27  abut the partition  23 , the spring being somewhat prestressed between the pin  27  and the axial stud  16  so that a vibration of the carriage  25  can be effectively suppressed. The clearance between the guide rail  44  and the back of the contact housing  1  is so minimal that there is hardly any vibration of the side walls  21 ,  22  and of the webs  30 ,  31 . 
     On the opening of the plug connection, with the slide  5  being pulled out of the contact housing  1 , the slide  5  entrains the carriage  25  since the support plate  27  abuts the partition  23 . As soon as the ramp  38  comes on to the oblique surface  49 , the web  31  is lifted over the catch  48  into the aperture  17 . After overcoming the catch  48  it passes into the cut-out  33  as shown in FIGS. 7 a  and  6   a . The distance between the support plate and the end plate does not change during the opening of the plug connection and is at maximum. The plug connection is thus again prepared for re-locking. 
     It should be noted that the above-described features of the exemplified embodiments can be combined with one another in any desired manner.