Plug-and-socket connection device

The invention relates to a plug-and-socket connection device for the automatic, e.g. multipolar electrical connection of a vehicle trailer, particularly of a semitrailer, to a towing vehicle, particularly to a prime mover. The plug-and-socket connection device comprises a socket and a plug, which can be mounted on the vehicle trailer (e.g. the plug) or on the towing vehicle (e.g. the socket, they can be aligned with one another when coupling the vehicle trailer to the towing vehicle, and can be displaced while being guided by a drive provided in the form of an, e.g. piston/cylinder assembly relative to one another between an (advanced) connecting position and a (retracted) inoperative position. Preferably, a cover of the socket can be opened by displacing, with the aid of the drive, the contact insert, which is accommodated in the socket and which supports the contact sleeves, in the direction of the connecting position, and can be closed once again when retracting the contact insert into the inoperative position. The invention is characterized in that the plug is mounted so that it laterally yields in an elastic manner against the action of at least one retaining spring that is fixed, on one side, to the plug and, on the other side, to a fastening flange that can be fastened to a vehicle (towing vehicle or vehicle trailer).

BACKGROUND OF THE INVENTION

The invention relates to a plug-and-socket connection device for the automatic electrical connection of a vehicle trailer, in particular of a semitrailer, to a towing vehicle, in particular to a prime mover, with a socket and a plug that can be mounted on the trailer and the towing vehicle, whereby as the trailer is being hitched to the towing vehicle the plug and socket can be mutually aligned and by means of a drive, e.g. in the form of a piston/cylinder assembly, can be displaced relative to each other between an advanced connection position and a retracted inoperative position. With the aid of the drive, e.g. a cover of the socket preferably opens automatically by displacement of the contact insert which is accommodated in the socket and carries the contact sleeves towards the connection point and closes again when the contact insert moves back into its inoperative position.

A plug-and-socket connection device of this type has already been proposed and the coupling position is supposed to be ensured by sensors. However, because of the usual large tolerances in vehicle building and the risk of the sensors becoming dirty during driving, the exact alignment of the plug with the socket is not that simple. Automatic operation of the coupling process is therefore called into question.

SUMMARY OF THE INVENTION

The object of the present invention is to propose a plug-and-socket connection device of the type mentioned, which without manual intervention provides considerable and automatic ease of connection between the two connector elements.

With a plug-and-socket connection device of the type mentioned this object is essentially achieved by the fact that the plug is mounted in a way allowing elastic lateral deflection against the action of at least one retaining spring attached both to the plug and to a mounting flange attached to a vehicle (prime mover or trailer).

The solution according to the invention ensures that the automatic union of plug and socket can be effected easily and securely even in the case of larger tolerances or inaccurate sensors.

In this context it should be mentioned that the terms “socket” and “plug” with regard to their respective functions as the two connector elements of a plug-and-socket connection device used in this description are mutually exchangeable i.e. those design features described and presented here for a socket or a plug can also apply in reverse. In order to keep the description simple the terms “socket” and “plug” are used in the following to distinguish between the two connector elements of a plug-and-socket connection.

In a special embodiment of the invention, the retaining spring for the plug is designed as a spiral spring surrounding the plug housing and preferably essentially coaxial with the housing. Furthermore, this spring preferably tapers in a forward direction. However, there may also be more than one retaining spring, e.g. three or four individual single springs acting symmetrically on the plug to re-center it after its lateral deflection. This ensures that after disconnection of the plug-and-socket connection the plug returns reliably to the correct starting position if it has been deflected laterally.

In a further development of the inventive concept the envisaged object is still better attained if the plug housing features a lead-in funnel for the socket, because with its aid the socket can be securely inserted into the plug even in the case of misalignment within the set tolerances.

The lateral deflection of the plug can be ensured in a simple manner if the plug housing is braced at the rear on a retaining plate by means of a ball bearing or simple spherical surfaces.

For further tolerance compensation in an axial direction, it is advantageous if the retaining plate, carried on the mounting flange for the plug housing, is braced by a return spring. This also ensures lateral swivelling of the plug housing against the action of the return spring as well as of the retaining spring(s) for the plug.

In order to largely prevent the contact pins of the plug from becoming dirty and yet ensure automatic establishment of the plug-in connection, the invention further proposes that the plug housing that accommodates the contact mount carrying the contact pins is sealed off in the rest position by a cover plate e.g. behind the lead-in funnel. This cover plate preferably features openings for the contact pins and can move, in particular slide, against the action of a return spring from the forward rest position and with release of the contact pins to a rearward connection position. In this way automatic opening and closing of the plug housing by insertion and retraction respectively of the socket is achieved. In the rest position, i.e. when not in use, the contact pins are protected. The arrangement is preferably so that in the rest position of the cover plate, the contact pins just close the openings. This also means that the contact pins can serve as guides for the to and fro motion of the cover plate.

For the protection of the inner space it may further be provided that the outer edge of the cover plate in rest position is pressed by its return spring against an inner shoulder of the plug housing if necessary by the interposition of a sealing ring.

A sealing ring may be mounted in the plug housing at the front end of a spacer sleeve.

To simplify assembly, the return spring for the cover may be a spiral spring surrounding the contact mount and is preferably fixed at its rear in a ring groove.

In accordance with a further inventive feature, the plug housing is equipped with a stopper accommodating a valve core which in assembled condition points downward. The valve core carries a baffle through which condensation water can drain while the infiltration of water (road spray, steam jets) from outside is prevented.

To secure the plug-in connection of plug and socket in the operative position and to reliably hold the socket in its inoperative position, the drive can be locked in either the operative or the inoperative position.

To facilitate assembly and disassembly, the contact insert can be detachably connected e.g. with a screw connection, to the piston of the drive, which may be a pneumatic piston-cylinder assembly.

In a further development of the invention, to ensure that the contact sleeves remain properly aligned with the contact pins of the plug, the contact insert of the socket may be mounted on a base plate, also serving as mounting plate, to resist torsion.

This base plate may be equipped with a housing section encompassing the contact insert and featuring ball elements distributed over its circumference. This allows the contact insert to be secured in two defined positions (starting position=unlocked, operative position=locked).

Optionally the plug-and-socket connection device of the invention may feature an emergency release which, in the case of power failure, allows mechanical separation of socket and plug. The plug- and-socket connection device may also feature protection of the socket against torsion, code protection of the socket, sensors for position detection, protection of the plug housing against being lifted from the retaining plate, and/or a locking device for the contact insert in inoperative and operative position to further increase the functional reliability.

DETAILED DESCRIPTION OF THE INVENTION

The plug-and-socket connection device shown in the figures which can be used in a truck/semitrailer combination and then must be mounted near the trailer coupling, consists of a plug S, for example mounted on the trailer, and a socket D, for example mounted on the towing vehicle. When the trailer is hitched to the towing vehicle, plug S and socket D must align automatically which is made possible mainly with the aid of sensors determining the position of the trailer relative to the towing vehicle. By means of a drive10in the form of a piston-cylinder assembly the two connector elements D, S are joined. The drive10is designed so that it can move the socket D from a retracted rest position while the connection is not in use to an advanced connection position when the connection must be established whereby the socket D cooperates with the plug S. When the plug-in connection is separated, the direction of movement of the socket D is reversed.

The socket D as shown most clearly inFIG. 1andFIG. 3Ahas a cover5consisting of two flaps. The flaps of the cover5can pivot on swivel pins9of a circular housing section16of a base plate2against the action of return springs4in the form of leg springs. As the contact insert1carried on the base plate2moves into the connection position, the two flaps of the cover5swivel outwards and return to their closing position by means of the return springs4when the contact insert1moves back to its rest position. To ensure tight sealing, the forward end of the contact insert1and of the housing section16is equipped with a sealing disc3against which the flaps of the cover5come to rest in closing position. Torsion-free operation of the contact insert1is ensured at the housing section16by means of an outer longitudinal groove14in the casing of the contact insert1and a corresponding inner longitudinal rib15of the housing section16. The contact insert is disconnectably attached to the front end of the piston17of the piston-cylinder assembly10by means of a hexagon socket screw. A cable7for the supply of the contact insert1is integrally cast into the base plate2and stress-relieved by means of a clamp13. The housing section16of the base plate2carries radially projecting ball elements8divided over its outside circumference which serve to hold the contact insert1in two defined positions (starting position=unlocked, operative position=locked).

The drive10is locked both in the advanced connection position and the retracted rest position of the socket D to secure the socket D against positional change in both positions.

For the tolerance compensation of the orientation of the two connector elements in relation to each other, the plug S as shown in theFIGS. 1,2and4is mounted to provide elastic lateral deflection against the action of a retaining spring213. The retaining spring213for the plug S is a spiral spring surrounding the plug housing29and if it is in the form of a double spiral spring is attached with its free rear ends33to a fastening flange210which can also serve as mounting flange on the vehicle. The retaining spring213tapers toward the front to give it the required reset characteristics.

The plug housing29is equipped at its front with a lead-in funnel30for the socket D for increasing misalignment tolerance. Moreover, the plug housing29is braced on a retaining plate27by means of a ball bearing26or simple spherical surfaces to allow lateral deflection against the action of the retaining spring213.

The plug housing29accommodates the contact mount28which carries the contact pins21,22. In the rest position, shown inFIG. 4, the plug housing29is closed by a cover plate23with openings for the contact pins21,22which just seal the openings in the rest position. The cover plate23is pressed against a sealing ring24in the form of a retaining ring on an inner shoulder31of the plug housing29by a return spring211.

The return spring211is a spiral spring which sits on the contact mount28and is held at its rear in a circumferential groove32of the contact mount28. The cover plate23is concave at the front matching the convex shape of the front of the socket D (seeFIG. 3) so that there is additional centering for the lead-in of the socket D into the plug S. The sealing ring24is mounted on the front end of a spacer sleeve25in the plug housing29. The cable214for the contact mount28is encapsulated in the contact mount28and the plug housing29.

The retaining plate27on which the plug housing29with the contact mount28is braced, is mounted to be axially displaceable against the action of a return spring212on the fastening flange210, which can also serve as mounting flange. The plug S can therefore elastically recede at the insertion of the socket D to compensate for jolts and/or tolerances. The return spring212is also a spiral spring and is accommodated at its front in a ring groove35of the retaining plate27and at its rear in a ring groove36of a fixed cross-plate37of the fastening flange210. In idle position, the retaining plate27rests at the front against stops38of the fastening flange210under pressure of the return spring212.

The plug housing29is equipped with a stopper216holding a valve core215, which points downward when assembled, so that condensation water can drain through a baffle created in the valve core while at the same time preventing the infiltration of water (road spray, steam jets) from outside.

In the embodiment of a plug-and-socket connection device consisting of socket D and plug S as per invention shown inFIG. 5the following particulars are pointed out: The contact insert1features an emergency release310which ensures that in case of system failure the components of the plug-in connection can be separated mechanically. A plastic holding fixture for the exit of the cable217simultaneously serves as protection against torsion and coding protection311of the socket D. The socket D further holds two sensors312which detect the two positions of the socket D (inoperative or operative). Laterally projecting ribs313on the plug housing29mechanically secure it against being lifted from the retaining plate while the socket D is being pulled from the plug S. Instead of the ball locking of the socket D, it is locked in the inoperative and operative position by means of a spring clip arrangement.

The embodiment of a plug S according to the present invention as shown inFIGS. 6 and 6A, essentially differs from those in theFIGS. 1,2and4by the elastically laterally deflecting suspension of the plug S to the fastening flange210. Here four individual springs213′ are used which re-center the plug S after a lateral deflection. The return spring212is divided into individual return springs212′.

Other serviceable spring mountings are of course also possible.

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