FIELD OF THE INVENTION

The invention relates to an arrangement in a telecommunications system for fitting a connection block in a cover so that a complete connecting means is obtained which can be connected to the front edge of a circuit board or in the back plane of a rack containing circuit boards.

DESCRIPTION OF PRIOR ART

In the Philips (Netherlands) data handbook from April 1978, Components and Materials, part 10, Connectors, there is shown under the catalogue number 433202625920 a typical example of how a connection block is at¬ tached in a cover with the help of a plurality of screws. This is the most usual way in the art of fitting a connection block into a cover, the block being provided with rows of terminals to which wires are to be connected. The cover thereby serves as protection for the terminals and wires.

SUMMARY OF THE INVENTION

In known embodiments, the problem occurs that the plastics material in the cover gradually cracks with repeated screwing or tightening with nuts in the material. A further problem is that when a complete con¬ nector, i e connection block and cover, is fitted to a circuit board and the cover needs to be removed, the whole connector must be removed so that the screws will be accessible, the electrical contact between board and connector thus being broken.

The arrangement in accordance with the invention is characterized ac¬ cording to the patent claim and solves the said problem by the cover being so formed that a standardized connection block, e g of the type prescribed in DIN standard 41612 (IEC standard 130-14), is pushed into the cover and thereby obtains guiding by guiding pins in the cover through the screw holes in the block which are normally used for screw¬ ed attachment. The cover is provided with resilient end walls on which projecting bosses directed towards the interior of the cover are ar¬ ranged. When the block is pushed into the cover, said end walls first

deflect outwardly but reassu e their original position when the block is pressed against the bottom of the cover, the bosses then snapping in over the edges of the short ends of the block to lock it to the cover. With the aid of a tool the cover can easily be removed from the block without interrupting the contact between the block and a connect ed circuit board. The advantages of the arrangement in accordance with the invention in relation to known arrangements is that apart from a stronger connector, there are also obtained large gains in time in fit ting and removing the connector, due to the technically simple solutio which in turn give considerable economic advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with the aid of an em¬ bodiment example, while referring to the attached drawing, on which

Fig 1 i llustrates the side of a cover from which a connection block sha be inserted

Fig 2 illustrates the cover seen from one side and

Fig 3 illustrates a cover seen from the back

PREFERRED EMBODIMENT

As is apparent from Figure 1, a cover 1 (a plastic cover according to the example) is provided with guiding pins 2 in the vicinity of each short end, tle task of these pins being to serve as guides for a con- nection block which is pressed into the cover. For said guidance the fact is utilized that the connection block is a standard block and the pins guide the block in the through-holes which in known embodiments.ar utilized for screws. It is thus not the connection block itself which is the inventive subject. It will be seen from the figure that bcth long sides of the cover 1 farthest out towards the end walls are pro¬ vided with slits 5 so that resilient end walls 3 are obtained. Each of the end walls 3 is provided en the inside with a projecting boss 4 directed towards the guiding pin 2. The bosses 4 are at a small

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distance from the pins 2. The task of the bosses is to snap in over the edges of the short ends of the block when the latter is fitted into the cover, thereby locking it in the cover. In conjunction with the respective guiding pin, the cover is provided with a stop projec- tion formed as a wall 6 of given height. The walls 6 have the task of defining the bottom position for the connection block in the cover. On the drawing, reference numerals 8 and 9 refer respectively to the cable inlet of the cover and space for locking means to circuit boards. These details are not connected with the invent concept and are only drawn in to give a complete picture of the appearance of the cover, thereby to facilitate understanding the invention.

Figure 2 illustrates the cover from one side with the details in ques¬ tion in cross-section. When a connection block is inserted into the cover, the guiding pins 2 are located in the screw holes of the block. The end surfaces of the block simultaneously press against the project¬ ing bosses 4 disposed on the resilient end walls 3. These bosses are formed with a slope obliquely outwards towards the bottom of the cover so that the block ends glide along the bosses and press the end walls 3 outwards. When the block comes into contact with the stop walls 6, the resilient end walls 3 deflect back and the bosses 4 snap in over the edge of the respective short end of the block to lock it to the cover.

From Figure 3, which shows the cover from the rear, it will be apparent that the cover is provided with openings 7 at the outer ends, through which openings the cover can easily be released from the block by a tool, without the block needing to be removed from the circuit board to which it is connected.

The object of the arrangement in accordance with the invention is thus to provide a cover with greater strength than in known arrangements, and to achieve a cover from which gives better economy by enabling a simple and rapid procedure when fitting and removing a block in the cover.