GB2111758A - Plug in module connector mount - Google Patents

Abstract

Plug-in modules such as printed circuit boards 30 mounted on cold plates 31 are received in opposed pairs of slots in spaced parallel heat- conductive metal plates, the inner edge of each module having electrical contacts to mate with a connector mounted at the inner end of the respective pair of slots and each module being firmly locked in its slots. The locking means may be carried by the edges of the module which engage in the slots. <IMAGE>

Description

SPECIFICATION Plug in module connector mount This invention relates to electrical (which term includes electronic) equipment practice, especially for use in data processing or telecommunication systems particularly military.

In such systems it is common practice for most if not all of the circuitry to be mounted on plug in modules which have contacts along one edge. Such boards are usually received in slotted guides in the equipment racks, with the contacts along one edge received in connectors at the ends of the slots. Plug in module location in such assemblies usually relies on close tolerances between the module guide slots and the rear assembly, plus the ability of a module to float to a certain extent in its guide slots. However, increasing problems with vibration and heat dissipation (especially with the high packing densities now used) necessitates the use of special devices to lock a module against vibration and to allow good head dissipative characteristics. Such devices create large alignment tolerances on engagement, but virtually zero float on locking.

An object of the invention is to provide an electrical equipment practice which enables the above difficulties to be overcome in a relatively inexpensive way.

According to the invention, there is provided an electrical equipment rack arrangement, which includes two parallel spaced-apart plates of heat conductive metal with slots in them on the facing surfaces thereof, which slots are in aligned pairs, a plurality of plug in modules each of which can be received in one of said aligned pairs of slots, contacts on that edge of each said module which is innermost of the module when fitted in the rack, and connectors each located in a connector support at the inner ends of a pair of slots for the reception of contacts on one of said plug in modules, wherein each said module is firmly locked in its said pair of slots and each said module has a backing plate of a heat conductive material in heat-conductive contact with said spaced apart plates when its module is in the rack, wherein each said connector support is a girder-like member which extends between the ends of the slots for one of said modules, and wherein said connector support is so arranged as to have a degree of guidance in both the vertical (i.e. between said plates) direction and in a direction of rightangles thereto, which arrangement facilitates the engagement of each said module's contacts with the appropriate one of said connector contacts and said connector support allows said mounted connector to flat sufficiently radially to compensate for nominal misalignment when said plug-in unit is clamped to its said pair of slots.

An embodiment of the invention will now be described with reference to the accompanying highly schematic drawings, in which: Figure 1 is a view from one face of a slotted rack arrangement for receiving modules, in this case printed circuit boards.

Figures 2 and 3 are two views of how a 'card-lok' (Trade Mark) device is used on each edge of a plug-in module to firmly clamp it in a guide slot.

Figure 4 is a view of on end of a connector support, which shows how it is secured in place.

Figures 5 and 6 are plan and side views of one end of a connector support, Figure 6 having portions cut away and being partly sectioned.

Figures7and8areviewssimilarto Figures 5 and 6 of the other end of a connector support.

Figure 9 is a view of a plug in module with a printed board and a heat dissipating metal plate.

Figure 10 is a side view, part-sectioned, of a component mounting as usable in an embodiment of the invention.

The rack into which the modules, in this case printed circuit boards, fit is shown in Figure 1, and consists of top and bottom plates 1, 2 of a good heat-conductive material, such as an aluminium alloy, having convection devices such as fins on the outer faces. These plates 1, 2, are formed with slots on their inner faces, each pair of slots, one in each plate, being able to receive a printed circuit board.

These two plates 1 and 2 are interconnected by end walls 3, 4.

At one end of the support, see Figures 5 and 6, there is on one side of the support a small collapsible feature or pimple 18a. At the other end there are similarfeatures 18b on one side, and similar features 17 on the end. These features ensure that the connector carrier faces opposite the features are in intimate contact with the slots, thus eliminating the need for expensive jigging arrangements. The con nectorcarriers are then locked in position either by screws or by rivets.

When the supports such as that of Figures 5 to 8 are used each has an end in to opposed slots in the plates 1,2, Figure 1. The module is slid into a pair of aligned slots until its connector engages with the support. The various sloping and other surfaces 19, 20 and 21 etc. provide primary guidance for the module on plug in.

When the module connector has engaged with the backplane connector the 'card-loks' are operated to clamp the module in place. Figures 2 and 3 show in simplified form how the 'card-bk' devices referred to above function. Each such device, as can be seen in Figure 3, is in several portions 7, 8 and 9, which are on a long threaded shaft 10. The width of this is such that when in the condition shown it fits into a slot in one of the plates 1, 2, see Figure 1. One such device is on each of two parallel edges of a printed circuit board, as can be seen in Figure 2.

Where thermal dissipation is a requirement for one of the circuit components, that component is fitted to a metal plate that is in direct thermal contact with the heat dissipating component. If the plug-in module is a printed circuit board the metal plate, known as a cold plate, has holes cut in it allowing component leads to pass through it to the printed circuit board, as can be seen from Figure 10.

When the board is fitted into a pair of slots in the plates 1 and 2, Figure 1, it is a relatively loose fit therein. However, when it is properly positioned in the slots, the screws such as 10 of its two 'card-lok' devices are rotated to move the portions together, with the result that the portions 7, 8 and 9 receive sideways motion. This causes the plug-in module to be locked into its slots, the contacts on the edge of the module being now rigidly fixed in relation to the position of the slots.

In Figures 5 to 8, the connector or connectors are located between the end portions of the support fitting through the slotted regions 15 and 16 of the support and fixed through the hole 22 in such a manner that radial float of the connector is guaranteed (by use of a threaded bush of example).

The arrangement of the cold plate is shown in Figure 9, where we see a module (printed circuit board) 30, mounted on a cold plate 31,which is held in place in the slots by 'card-bk' devices 32, 33.

Claims (4)

1. An electrical equipment rack arrangement, which includes two parallel spaced-apart plates of heat-conductive metal with slots in them on the facing surfaces thereof, which slots are in aligned pairs, a plurality of plug-in modules each of which can be received in one of said aligned pairs of slots, contacts on that edge of each said module which is innermost of the module when fitted in the rack, and connectors each located in a connector support at the inner ends of a pair of slots for the reception of contacts on one of said plug-in modules, wherein each said module is firmly locked in its said pair of slots and each said module has a backing plate of a heat conductive material in heat-conductive contact with said spaced apart plates when its module is in the rack, wherein each said connector support is a girder-like member which extends between the ends of the slots for one of said modules, and wherein connector support is so arranged as to have a degree of float in both the vertical (i.e. between said plates) direction and in a direction at right-angles thereto, which arrangement facilitates the engagement of each said modules contacts with the appropriate one of said connector contacts and said connector support allows said mounted connector to float sufficiently radially to compensate for nominal misalignment when said plug-in unit is clamped to its said pair of slots.

2. A rack arrangement as claimed in claim 1, and in which each said connector support has collapsible portions at its ends and sides to give said float.

3. An electrical equipment rack arrangement substantially as described with reference to the accompanying drawings.

New claims or amendments to claims filed on 4th October 1982 Superseded claims None New claim:

4. An electrical equipment rack arrangement, which includes two parallel spaced-apart plates of heat-conductive metal with slots in them on the facing surfaces thereof, which slots are in aligned pairs, a plurality of plug-in modules each of which can be received in one of said aligned pairs of slots, contacts on that edge of each said module which is innermost of the module when fitted in the rack, and connectors each located in a connector support at the inner ends of a pair of slots for the reception of contacts on one of said plug-in modules, wherein each said module when inserted into a pair of said slots is firmly locked in its said pair of slots, wherein each said module has a backing plate of a heatconductive material in heat-conductive contact with said spaced apart plates when its module is in the rack, wherein each said connector support is a girder-like member which extends between the ends of the slots for one of said modules, wherein a said connector support has on one of its ends a bent-over portion which has a degree of flexibility, so that the support has a degree of float in the vertical (i.e.

between said plates) direction, wherein the connector support also has on its sides at the ends thereof collapsible portions such that the connector support also has a degree of float in a direction at rightangles to the first direction of float, which arrangement facilitates the engagement of each said module's contacts with the appropriate one of said connector contacts, and wherein the float-providing arrangements for said connector support allow the mounted connector to float sufficiently radially to compensate for nominal misalignment when a said plug-in unit is clamped to its said pair of slots.