Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1998-12-10
2001-06-12
Gandhi, Jayprakash N. (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S756000, C361S801000, C361S802000, C439S377000
Reexamination Certificate
active
06246585
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention pertains to a card-holding device for the locking of a printed circuit card in a guide rail/rack of a subassembly/subrack or such, with a retaining element, that in case of a printed circuit card having been inserted into the guide rail lies in front of the front edge of the card and for withdrawing the printed circuit card can be swiveled out of the way against an elastic restoring force.
Printed circuit cards with electric or electronic components, which are mounted in subracks or other housings of the insertion technology, are normally guided on their longitudinal edges in guide rails, which makes it possible that they may simply be pushed into the subrack or the housing and pulled out again as needed.
Normally, the printed circuit card-holding devices are provided at their rear edge with plug and socket transfer connectors which establish the electrical connection with the subrack or the housing. Although the pinching effect of the plug and socket transfer connector, especially for multipole designs, holds the printed circuit cards in their inserted position, additional safety measures are required to hold the printed circuit card in its inserted position particularly for printed circuit cards not provided with a frontal plate piece and which, depending on the application, may be subjected to vibrations or irregular transverse accelerations. Separate card-holding devices serve this purpose.
A card-holding device of the type mentioned in the beginning is, e.g., known from the publication Hoffman/Schroff: “Katalog für die Elektronik 96/97” (Catalog for electronics), pages 37.46 and 37.47: The card-holding device depicted there includes as retaining element an elastically deformable safety latch (shackle) that as a matter of choice has to be swiveled out of the way either by hand (e.g., with the thumb) or with an in/out lifting handle to allow pulling the printed circuit card out. The safety latch is here part of a component mounted in front of the guide rail in the area of a front module rack of a subassembly/subrack.
The disadvantage of the known card-holding devices is noticeable on insertion (push-in) of a printed circuit card into its guide rails: Since the safety latch of such a card-holding device, due to the elastic restoring force acting on it, reverts (moves) back to its idle position, i.e. the latched (locked) position as soon as the printed circuit card is completely pulled out, it interferes appreciably with the insertion of the printed circuit card: The printed circuit card must then not only be introduced into its two guide rails, but additionally the safety latch of the card-holding device has to be swiveled out of the way against the elastic restoring force in order to allow the insertion of the printed circuit card at all. This process gets to be especially cumbersome if card-holding devices are mounted on both guide rails for the acceptance of the printed circuit card.
Starting with this state of the art, the invention is based on the objective to improve a card-holding device of the type mentioned at the beginning such that it is only activated if a printed circuit card has been inserted into the associated subassembly/subrack or housing; i.e. the card-holding device should not hinder the push-in (insertion), especially the feeding of a printed circuit card into the associated guide rails.
SUMMARY OF THE INVENTION
A card-holding device according to the invention for the securing of a printed circuit card in a guide rail of a subassembly/subrack or such contains, therefore, not only a retaining element that in case of a printed circuit card inserted in the guide rail is located in front of its front edge and can be swiveled out of the way against an elastic restoring force, but also an activating element that is elastically coupled with the retaining element and in case of an inserted printed circuit card inflicts upon it the elastic restoring force while it lies against a longitudinal edge of the inserted printed circuit card. In case of the printed circuit card having been removed (pulled out), the activating element is freely movable and the elastic restoring force onto the retaining element is eliminated.
The securing property of the card-holding device according to the invention is unchanged compared to the state of the art, but the disadvantages of the known card-holding devices described above are eliminated: The card-holding device according to the invention is automatically engaged by its activating element as soon as a printed circuit card is being inserted into the respective guide rail; however, if no printed circuit card is present in the associated guide rail, then the card-holding device according to the invention is inactive. Since the activating element in the latter case exerts no elastic restoring force onto the retaining element, the retaining element remains in the opened position; an insertion of a printed circuit card is problem-free and possible without interference by the retaining element.
Therefore, the invention makes available a card-holding device with alternately stable end positions, i.e. an open position of the retaining element and a latched position. The always stable final (end) position of the card-holding device is in each case created automatically by the insertion (push-in) or the withdrawal (pull-out) of a printed circuit card.
A preferred execution of the invention consists of the retaining element and the activating element having a common pivot point. It is here especially advantageous, if the retaining element and the activating element form a ductile rocker: The rear part of the rocker projects in case of an opened card-holding device beyond the insertion plane of the guide rail and is pressed down by a printed circuit card being pushed into the guide rail. By this, due to the elastic ductility of the rocker, a force is generated onto the proximal (front) part of the rocker—the retaining element—whereby it after the passing of the front edge of the printed circuit card snaps upward. Hence, according to this preferred design form of the invention, the retaining element and the activating element are made in one piece, where additional components like, e.g., springs, are eliminated for an elastic coupling between these parts. The mounting of the rocker on or in front of the guide rail occurs in a suitable manner with a bearing/support element that is fastened at the installation point and in which the rocker is supported at its pivot point.
Useful is an in/out lifting handle for the printed circuit card, with which the retaining element—with utilization of the laws of leverage (levers)—can be swiveled away from the front edge of the printed circuit card to make a withdrawal of the printed circuit card feasible. If the retaining element and the activating element of the invention are constructed as a rocker that is supported in a bearing element, it is advantageous if a first and preferably also a second push-off shoulder is provided for the in/out lifting handle, where the in/out lifting handle supports itself on the first push-off shoulder in order to facilitate the withdrawal of the printed circuit card, whereas it supports itself on the second push-off shoulder to aid the insertion of the printed circuit card.
The retaining element can be a safety latch, the construction (design) of which can be realized particularly simple. The activating element can also be constructed as a shackle, and appropriately has a run-up ramp for the printed circuit card.
If the activating element structured as a shackle is part of a spring frame formed onto the retaining element, the card-holding device according to the invention can be especially advantageously realized: The retaining element may then possess the internal stability required for the securing (latching) effect, where the activating element constructed as a shackle (latch)—due to the elastic ductility of the spring frame—is elastically coupled with the retaining element. The such structured card-holding device can also be man
Gunther Hans-Ulrich
Haag Volker
Joist Michael
Mazura Paul
Pfeifer Klaus
Gandhi Jayprakash N.
Merchant & Gould P.C.
Schroff GmbH
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