GB2316549A

GB2316549A - Sealed electrical coupling

Info

Publication number: GB2316549A
Application number: GB9717198A
Authority: GB
Inventors: Wilfried Weigel
Original assignee: DBT GmbH; DBT Deustche Bergbau Technik GmbH
Current assignee: Caterpillar Global Mining Europe GmbH
Priority date: 1996-08-21
Filing date: 1997-08-13
Publication date: 1998-02-25
Also published as: DE29614501U1; GB9717198D0

Abstract

A coupling has a connector 1 with a circumferential seal 16 and a counterpart 2 with a seal seat 14 and a circumferential seal support collar 15 extending towards the connector 1. The connector and counterpart are kept together by a screw 10 and nut 13. The nut 13 is moulded into the counterpart 2. A multi-core cable exits the connector 1 at right angles through guide 7. The counterpart 2 has external terminals.

Description

Pluq-and-Socket Connection for Electronic Device and the like The invention relates to a plug-and-socket connection for electronic devices and the like, in particular for devices in underground mining such as, chiefly, electrohydraulic lining controls, in accordance with the type specified in the preamble of Claim 1.

Electric plug-and-socket connections of the aforesaid type are known and are used to effect the electric cable connections in electrohydraulic lining controls for underground mining such as are known, for example, from DE 37 08 902 C2. Conventional electric plug-and-socket connections have not always proved to be sufficiently watertight in long-term use in moist surroundings and especially in areas at risk from splash water such as occur in underground mining extraction operations. Leaks in the plug-and-socket connections can lead to serious breakdowns.

It is therefore the object of the invention to design the electric plug-and-socket connections known per se in a simple way such that the required tightness is reliably provided even in the case of long-term use in moist surroundings and, in particular, in splash water areas such as occur, above all, in underground mining operations.

According to the invention, on the plug-on side of the male connector the electric terminal fitting has on its plastic housing a circumferential collar, which projects towards the plug-on side of the male connector over a sealing seat, serving to support the circumferential seal, of the terminal fitting, and which embraces the plugged-on male connector at the opening of its plastic housing.

Thus, according to the invention the terminal fitting of the plug-and-socket connection has on its e.g. plastic housing an integrally formed collar which sur rounds its sealing seat for the circumferential sealing ring and projects over the sealing seat towards the plugon side of the male connector arranged at the cable end, and into which, in conjunction with screwing in and tightening the central locking screw, the male connector is pressed in with the opening, serving the purpose of sealing mounting, of its housing, with the result that the seal consisting of rubber or deformable plastic material is deformed with strong pinching by the screwing force between the sealing seat of the terminal fitting and the seating surface of the male connector to such an extent that the circumferential gap at the inner circumference of the collar can be reliably closed, and thus a reliable seal can be achieved. In this case, in the nondeformed state the seal preferably has a width such that in the plugged-on state of the male connector a circumferential gap forming the specific pinching deformation of the seal is present between this seating surface and the inner surface of the collar. Furthermore, with regard to the required high degree of tightness of the plug-andsocket connection it is advantageous when the circumferential seal has a comparatively high volume. Consequently, in the non-deformed state the seal can have a thickness which is larger than the height of the collar.

In any case, the circumferential collar limits the degree of deformation of the seal in the circumferential region of the sealing seat, with the result that under the action of the force of the locking screw the seal is specifically deformed such that, above all, it is pinched towards the free end of the collar and, in the process, reliably surrounds the gap region towards the end of the collar, it also being possible to pinch it over the collar given an appropriate setting of its thickness. The collar can be given a height which corresponds at least approximately to the width of the sealing seat.

In detail, the arrangement can be made advantageously such that the circumferential seal is arranged on the connection side of the plastic housing of the male connector and surrounds an inserted piece, receiving the electric male elements, of the plastic housing of the male connector. The threaded sleeve into which, with the male connector plugged on, the locking screw penetrating an opening in said male connector is screwed preferably comprises a metal sleeve which has an inner thread and is fixed on the plastic housing of the terminal fitting, for example, by welding, as a result of which it is possible to achieve a screwing force which is advantageously high with regard to the pinching deformation and sealing of the plug-and-socket connection.

As is known per se, the said terminal fitting can be designed as a plug-in connector whose electric plug pins consisting of metal project from the plastic housing of the terminal fitting on the side opposite the plug-on side of the male connector, with the result that, for the purpose of producing the electrical connections, said terminal fitting can be plugged onto an electric device, for example onto a valve control block of an electrohydraulic lining control known per se. Furthermore the projecting collar may have an approximately square contour with bevelled corners, to correspond to the shape of the plastic housing of the male connector and of the terminal fitting, the above-mentioned seal then comprising a correspondingly-shaped square ring of deformable rubber or plastic material.

The invention is explained in more detail in conjunction with the exemplary embodiment shown in the drawings, in which: Figure 1 shows, greatly enlarged, a plug-andsocket connection according to the invention, in which the male connector is detached from the electric terminal fitting, the male connector and the terminal fitting each being shown in section; Figure 2 shows, in the sectional representation of Figure 1, the terminal fitting with the sealing arrangement according to the invention, before its pinching deformation, the male connector being shown only diagrammatically in the region of its opening arranged on the plug-on side of the plastic housing.

The basic design of the plug-and-socket connection shown in the drawing is shown and comprises an electric male connector 1 and an electric terminal fitting 2 to which it is possible to connect the male connector 1, which is connected to the end of an electric cable, for the purpose of producing the electric line connections. The male connector 1 has a plastic housing 3 which accommodates a plurality of, here four electric male elements 4 which consist of metal, are arranged at the corner points of a square, and are located on an inserted piece 5, which consists of plastic, is plugged from below into an opening of the plastic housing 3 and is fixed in the latter, for example by being clamped or in another way. The male elements 4 are constructed here in each case roughly in the shape of a fork, and have upper terminal lugs 4' to which the electric cable strands of the cable bearing the male connector 1 are connected in the manner known. At right angles to the longitudinal direction of the male elements 4, the housing 3 has a cable entry opening into whose internal thread it is possible to screw a threaded sleeve 7 which is plugged onto the end (not shown) of electric cable and penetrated by the latter, the bared cable strands being electrically connected in the housing 3 to the male elements 4 at the terminal lugs 4'. Located in the cable entry opening is a sealing ring 8, which consists of rubber or elastic plastic material, surrounds the cable end and, by screwing it in the threaded sleeve 7, can be deformed elastically so far that it firmly reclamps the cable at its end where the cable strands are bared, and thus fixes the male connector 1 at the cable end while sealing it with respect to the plastic housing 3. Moreover, the plastic housing 3 is provided in the middle between the four male elements 4 with a plug-through opening 9 for an axial locking screw 10 with the aid of which the male connector 1 connected at the terminal fitting 2 can be detachably connected to the terminal fitting 2.

This embodiment of the male connector 1 is known and therefore requires no further explanation.

The terminal fitting 2 has a plastic housing 11 which accommodates the electric contact elements, corresponding to the male elements 4, in the form of metal plug pins 12, and which has a square contour with bevelled corners. In the exemplary embodiment shown, the terminal fitting 2 is designed as a plug-in connector whose electric plug pins 12 project in a sealed fashion from the plastic housing 11 of the terminal fitting on the side opposite the plug-on side of the male connector 1, with the result that, in order to produce the electric line connections, the terminal fitting can be connected to a component, for example to the valve control block of an electrohydraulic lining control. Arranged fixed in the middle in the plastic housing 11 between the plug pins 12 is a threaded sleeve 13 which is parallel to them and is provided with an internal thread into which the locking screw 10 can be screwed. The threaded sleeve 13 preferably comprises a metal sleeve which is permanently arranged in the plastic housing 11, for example by bonding or welding to the plastic housing 11.

On the plug-on side of the male connector 1, the plastic housing 11 of the terminal fitting 2 has a sealing seat 14 which is formed by a cutout, located here, in the plastic housing 11 and is, like the latter, designed to have an approximately square contour with bevelled corners. The circumferential sealing seat 14 is limited at its outer circumference by a collar 15 which projects towards the plug-on side of the male connector 1 over the circumferential sealing seat 14, and which, in accordance with the contour of the plastic housing 1, has a square contour with bevelled edges of the square.

It may be seen from Figure 1 that on the opening side, facing the terminal fitting, of its plastic housing 3 the male connector 1 has a circumferential seal 16 made from rubber, or an elastically deformable plastic material, which surrounds the inserted piece 5 to provide a sealing mounting and which, at the rear, is located bearing against a seating surface 17 of the plastic housing 3. The seal 16 comprises a circumferential sealing ring which is designed in a square fashion with bevelled edges in accordance with the contour of the seating surface 17 and of the inserted piece 5.

When the plug-and-socket connection is being produced, the male connector 1 fixed on the cable end is plugged with its inserted piece 5, partially projecting from the plastic housing 3, into the correspondingly adapted inner opening of the terminal fitting 2, it being the case that the fork-shaped male elements 4 are pushed, producing the electrical connection, onto the plug pins 12 located in the plastic housing 11 of the terminal fitting 2, and the circumferential seal 16 is simultaneously pushed into the region of the sealing seat, surrounded by the collar 15, of the terminal fitting 2, with the result that, as shown in Figure 2, the seal 16 bears against the sealing seat 14 of the terminal fitting 2.

Subsequently, the locking screw 10 is plugged through the plug-through opening 9 on the plastic housing 3 of the male connector 1 and screwed with its screwed shank into the internal thread of the threaded sleeve 13 of the terminal fitting 2. When the locking screw 10 is screwed in and tightened, the circumferential seal 16 is clamped between the sealing seat 14 and the seating surface 17 and is deformed in the radial direction towards to the circumferential collar 15 and so strongly pinched in the process that it is pressed under the action of the screwing force against the inner surface of the collar 15 and in so doing produces a reliable seal between the male connector 1 and the terminal fitting 2. It is expedient for the seal 16, like its seating surface 17 as well to have transverse to the plug-on direction of the male connector 1 a width which is smaller than the width of the sealing seat 14 on the terminal fitting 2, so that when the male connector 1 is plugged onto the terminal fitting 2 there is present between the seal 16 when it is not as yet deformed and the inner surface of the collar 15 a gap into which, when the locking screw 10 is screwed in and tightened, the material of the seal 16 is pinched, being pressed in a sealing fashion against the inner surface of the collar in the process. In this case, the circumferential seal 16 can advantageously have in the non-deformed state a thickness d which is equal to, or else larger than the height of the collar, that is to say the measure by which the collar 15 projects over the sealing seat 14. In this case, the seal 16 has a volume such that when the locking screw 10 is tightened said seal is subjected to such a strong pinching deformation that not only is the gap towards the inner surface of the collar 15 closed, but in some circumstances the seal is pinched via the free outer edge of the collar 15, covering said outer edge, the result being to achieve a particularly reliable seal at the point of connection of the male connector 1 to the terminal fitting 2. For the rest, the locking screw 10, which is screwed into the threaded sleeve 13, is used for the purpose of connecting the plugged-on male connector 1 reliably to the terminal fitting 11, and thus the electric line connection is ensured.

The threaded sleeve 13 and the central locking screw 10, which can be screwed into it, are expediently produced from high-grade stainless steel.

The plug-and-socket connection according to the invention can be used in a versatile fashion for electrically connecting electric devices and other parts and, as described, permits a reliably tight connection of the male connector 1 to the assigned electric terminal fitting 2, with the result that this plug-and-socket connection can be used with particular advantage wherever, such as in splash water areas, in particular, high demands are placed on tightness. The plug-and-socket connection is preferably used for electrically connecting electronic devices in underground mining, specifically, in particular, in conjunction with electrohydraulic lining controls such as are used in underground mining extraction operations. In a departure from the exemplary embodiment described, the terminal fitting 2 can also be a permanent component of a device, for example of a valve control block known per se as is customary in electrohydraulic lining controls.

Claims

Claims:

1. Plug-and-socket connection for electronic devices and the like comprising a male connector, whose plastic housing has a plurality of electric male elements, arranged parallel to one another, and, at right angles thereto, a cable entry opening for a multi-strand electric cable whose cable strands are connected in the plastic housing to the electric male elements, and which is fixed in the cable entry opening under a seal, and having an electric terminal fitting which is constructed in the fashion of a socket-outlet and has metal plug pins or the like arranged in its plastic housing in alignment with the male elements of the male connector, as well as, in the middle, a central threaded sleeve into which, with the male connector plugged in, a locking screw arranged parallel to its male elements can be screwed, a circumferential, compliant seal being provided between the plastic housings of the terminal fitting and the pluggedin male connector, wherein on the plug-on side of the male connector the terminal fitting has on its plastic housing a circumferential collar, which projects over a sealing seat, serving to support the circumferential seal, of the terminal fitting, and which embraces the plugged-on male connector at the opening of its plastic housing.

2. Plug-and-socket connection according to Claim 1, wherein in the non-deformed state the circumferential seal has a thickness which is larger than the height of the collar.

3. Plug-and-socket connection according to Claim 1 or 2, wherein, in the non-deformed state, the seal which bears against a seating surface of the plastic housing of the male connector, has a width such that a gap for the pinching deformation of the seal is present between the seal and the inner surface of the collar.

4. Plug-and-socket connection according to any one of Claims 1 to 3, wherein the circumferential seal is arranged on the connection side of the plastic housing of the male connector and surrounds an inserted piece, receiving the electric male elements of the plastic housing of the male connector.

5. Plug-and-socket connection according to any one of Claims 1 to 4, wherein the threaded sleeve for the locking screw comprises a metal sleeve which has an internal thread and is fixed in the plastic housing of the terminal fitting, for example by welding.

6. Plug-and-socket connection according to any one of Claims 1 to 5, wherein the terminal fitting is designed as a plug-in connector whose electric plug pins project from the plastic housing of the terminal fitting on the side opposite the plug-on side of the male connector.

7. Plug-and-socket connection according to any one of Claims 1 to 6, wherein the projecting collar of the terminal fitting has an approximately square contour with bevelled corners for the purpose of matching the shape of the plastic housing of the male connector and of the terminal fitting, and the seal comprises a square ring which is made from deformable rubber or plastic material and is appropriately shaped.

8. A plug-and-socket connection substantially as described herein with reference to and/or as illustrated in the accompanying drawings.