JPH0645011A - Contact element of spring steel plate - Google Patents

Abstract

PURPOSE: To provide a contact element manufactured simply and at a low cost by which a front panel and a screw hole frame can be brought into contact mutually without impeding fastening coupling among the front panel, the screw hole frame, and a module rail. CONSTITUTION: A contact element made of a spring steel plate is used for conductive coupling between a screw hole frame 13 which is inserted into the front open receiving slit 12 of the module rail 11 of an assembly support body and a front panel element piece 15. The contact piece 1 is formed into U-shaped, supports contact tip portions 5 arranged symmetrically outside a U-shaped back portion 2, and two U-shaped leg portions are formed as spring legs 4 with fastening protrusion portions 6 which are for being inserted into the screw hole 14 of the screw hole frame 13. The proposed contact piece 1 is made of a single piece of thin steel plate, and can be later inserted into the screw hole frame 13 in the simplest way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a contact tip portion that pushes the back surface of an upper mounted front panel element by spring stress, and inserts it into a receiving groove opened forward of a module rail of an assembly support. The present invention relates to a contact element made of a spring steel plate for conductively coupling an existing screw hole frame to a front panel element.

[0002]

2. Description of the Related Art In an assembly support used for housing electrical and electronic assemblies, a front panel piece (a front panel piece of each part constituting the front panel) for closing the front part of the equipment is often It must be conductively coupled to other metal parts, in particular the module rail, in a reliable manner. By doing so, a protective conductor function can be achieved, which contributes to the safety of the operator or protects the electronic device incorporated therein. Furthermore, if the built-in electronic device has to be shielded against interfering electromagnetic waves, it is necessary to electrically couple all casing parts to one another.

The desired electrical connection between the module rails of the assembly support and the front panel pieces can be achieved in various ways. For example, various fixing screws can be used on the front panel pieces to simultaneously make an electrical connection. For this purpose, of course, the screw must have a metal connection (metal-to-metal connection) both to the front panel part and to the screw hole frame inserted in the module rail. However, since the front panel is usually coated with a non-conductive anticorrosion coating such as paint, only when special measures are taken to penetrate this surface film, the front panel and the module rail are fixed with the fixing screw. Conductive coupling is achieved.

There is known a spring element that is inserted into a groove of a module rail and has a contact tip portion that contacts the module rail and the front panel or the front panel element. The disadvantage of these spring elements is their relatively large size,
Therefore, it cannot be incorporated into a small assembly. Moreover, it is very difficult to retrofit a finished device with such a spring element.

Finally, West German Patent Application Publication No. 371721
No. 9 discloses a sleeve-shaped contact spring with a longitudinal slit. From the front side, this contact spring can engage with an extension of the receiving groove of the module rail provided in front of the screw hole frame. Next, when the front panel is screwed, the contact portion is elastically deformed and supported by the inward side surface of the expansion groove. The disadvantage of this device is
This is a point that manufacturing error directly affects contact. For example, tightening the fixing screw ensures that the front panel and the screw hole frame make contact through the contact element, but the tightening between the front panel, the screw hole frame and the module rail is no longer guaranteed, so that the mounting frame is securely connected. Electrical coupling is not always achieved. Furthermore, the contact springs, which are rather complicatedly shaped, have the disadvantage that they can only be inserted into module rails with special expansion grooves. Moreover, it is only possible with great difficulty to remove the contact element once engaged again from the expansion groove.

Contact elements are known which have an H-shaped cross section and are inserted into the receiving groove in front of the screw hole frame of the module rail, for making a conductive connection between the front panel and the module rail of the assembly support. There is. Triangular contact points on both sides connect the front panel and the screw hole frame by their tips. However, the production of this contact is not so easy and the assembly is complicated (DE-GM890).
6 492).

Further known is a conductive locking device consisting of a flat spring for making a conductive connection between the front panel of the plug assembly and the front face of the module rail of the assembly support. However, in this case, since the screw hole frame does not directly conductively couple with the back surface of the front panel, in many cases, sufficient attenuation of jamming radio waves cannot be achieved (DD-PS 241176).

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to enable a secure contact between a front panel and a screw hole frame without disturbing the tightening connection between the front panel, the screw hole frame and the module rail. To provide a contact element that can be retrofitted quickly and easily to an existing assembly support without tools and can be removed again without problems if necessary, and is particularly simple and inexpensive to manufacture. Is.

[0009]

The solution to this technical problem is premised on a contact element made of a spring steel plate, as described at the beginning. For the above purpose, the contact element is essentially U-shaped, with the U-shaped back part supporting the contact tip on the outside thereof and the two U-shaped legs for being inserted into the screw holes of the screw hole frame. Achieved by being formed as legs.

The contact element formed according to the invention can be manufactured from spring steel plates in a simple manufacturing technique while saving material. This contact element allows the spring legs to be most easily inserted into the two screw holes of the screw hole frame without any structural modification of the module rail. In this way, it is possible without problems to retrofit existing equipment.

For assembly, the contact element is held by fingers and the spring leg is inserted into the screw hole frame. The length of the U-shaped back, and thus the distance between the two spring legs, is then selected to correspond to the distance between the holes of the screw hole frame. It has been found suitable to straddle one unthreaded screw hole of the contact element.

The U-shaped back has an outwardly directed arched curve, where appropriate such that the outwardly directed contact tips are symmetrically arranged with respect to this curve. Is desirable. If the radius of curvature is chosen so that the contact tip protruding outwards when the contact element is inserted projects above the end face of the module rail, the contact element will be elastic when screwing the front panel piece. It deforms, the contact tip being pressed against the back side of the front panel and the spring force is large enough to penetrate the non-conductive coating.

In a preferred construction of the invention, the spring legs are provided with outwardly directed clamping projections. This makes assembly particularly easy, as will be described below. For installation, the contact element is held between the thumb and forefinger and first the free ends of the appropriately chamfered spring legs are inserted into the screw holes of the screw hole frame. The spring legs are then of such a length that they are already reliably guided into the screw holes when the rest of the contact element is still outside the rail profile and therefore still well retained. When the spring leg is firmly supported in the hole, the rest of the assembly can be done by pressing the highest point of the returned U-shaped back with a fingertip. Thereby, the elastic resistance of the clamping projection is overcome and the contact element is snap-fitted in its intended assembly position.

Since the spring legs are folded back inward from the U-shaped back at an acute angle, it is sometimes advantageous to have a hands-on manner in which the ends of the spring legs face each other closer than the corner area formed by the U-shaped back. This geometry simplifies the insertion of the contact element into the screw hole, and the spring leg is reached a few millimeters as soon as it is inserted into the hole. An inclination of about 10 degrees with respect to the spring legs is sufficient.

Conveniently, the U-shaped back is wider than the spring legs. The resulting transition between the spring leg and the U-shaped back can form an acute angled corner. These corners, by themselves, rest in contact with the front surface of the screw hole plate, even if there is a flash in the edge area of the screw hole. It is sufficient that the angle formed by these corners is about 85 °.

The contact element formed according to the invention is manufactured by stamping and bending from a single piece of thin spring steel. The contact tip can then be formed as a triangular tongue spring, which is preferably bent outwards from the U-shaped back.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

According to FIG. 1, the contact element 1 is in the form of an inverted capital U. In this case, the U-shaped back part 2 has an arch-shaped curved part 3 facing outwards, and the two U-shaped legs are formed as spring legs 4. Two contact tips 5 are arranged symmetrically outwardly with respect to the curved portion 3. The spring leg 4 is provided with an outwardly directed clamping projection 6. The free end 7 of the spring leg 4 is chamfered.

The contact element 1 consists of a single thin spring plate (see FIG. 2).
It can be manufactured by punching and bending. The contact tip portion 5 is formed as a triangular tongue-shaped spring piece bent outward from the U-shaped back portion 2.

The spring leg 4 is folded back inwardly from the U-shaped back 2 at an acute angle so that the end 7 of the spring leg 4 faces closer than the corner area 8 formed by the U-shaped back 2. Thereby, the spring legs 4 are inclined with respect to each other at an angle of about 10 degrees. The width of the U-shaped back 2 is
As is particularly apparent in FIG. 2, it is about twice the width of the spring leg 4 formed integrally therewith. The corner 9 formed by the transition between the spring leg 4 and the U-shaped back 2 is about 85
It forms an acute angle of 10 degrees.

An assembly support for accommodating an electronic assembly is shown in excerpt in FIGS. 3 and 4. Front module rail 11 of this assembly support
Has a receiving groove 12. A screw hole frame 13 having screw holes 14 at equal intervals is inserted into the receiving groove 12. The assembly support is closed at the front by a plurality of front panel pieces 15 which together form the front of the device. Each front panel 15 is fixed by a fixing screw 16.
Since it is screwed to the screw hole frame 13, a tightening connection occurs between the front panel element 15, the screw hole frame 13 and the module rail 11.

Before the front panel element 15 is screwed, the contact element 1 can be fitted into each of the two screw holes 14 of the screw hole frame 13. For this purpose, the contact element 1
Insert the spring leg 4 into the screw hole 14,
Must be pressed to clip.

The attached contact element 1 is held in the screw hole frame 13 by means of a clamping projection 6 provided on the spring leg 4. The curved portion 3 of the U-shaped back portion 2 is defined so that the contact tip portion 5 projects slightly forward from the module rail 11. As a result, the contact tip 5 is pressed against the back surface of the front panel piece 15 to be screwed next, and penetrates into the surface layer of the front panel piece 15.

The contact element 1 ensures an electrically conductive connection between the front panel element 15 and the screw hole frame 13, the front panel element 15 and the screw hole frame 13 themselves being again connected to the module rail 11 by clamping. To be done. The spring process realized by the bend 3 compensates for possible dimensional tolerances.

[Brief description of drawings]

FIG. 1 is a view in which a contact element is significantly enlarged, a is a front view,
b is a side view.

2 is a plan development of the contact element according to FIG.

FIG. 3 is a front view (partially sectional view) of two contact elements used in one assembly support.

FIG. 4 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contact element 2 U-shaped back part 3 Bending part 4 Spring leg 5 Contact tip part 6 Clamping protrusion part 7 End part 8 Corner area 9 Corner 10 Angle 11 Module rail 12 Receiving groove 13 Screw hole frame 14 Screw hole 15 Front panel element 16 Fixing screw

Claims (5)

[Claims] 1. A contact tip portion for pressing a back surface of a front panel element mounted on the back surface by spring stress,
In the contact element of the spring steel plate for electrically conductively coupling the screw hole frame and the front panel piece inserted in the receiving groove open to the front of the module rail of the assembly support, the contact element is essentially It is formed in a U-shape, in which case the U-shaped back (2) bears the contact tip (5) on its outside and two U-shaped legs are provided in each screw hole (14) of the screw hole frame (13). ) Spring legs (4) for insertion into
A contact element characterized by being formed as. 2. Contact element according to claim 1, wherein the U-shaped back (2) has an outwardly facing arched curve (3). 3. Two outwardly facing contact tips (5)
3. The contact element according to claim 2, wherein the contact elements are arranged symmetrically with respect to the curved portion (3). 4. The contact element according to claim 1, wherein the spring leg (4) comprises an outwardly directed clamping projection (6). 5. The end (7) of the spring leg (4) is
Corner section (8) configured with a U-shaped back (2)
5. Contact element according to any one of the preceding claims, wherein the spring legs (4) are folded back inwardly from the U-shaped back (2) at a sharp angle so as to face each other closer.