GB1604368A

GB1604368A - Printed circuit board support system

Info

Publication number: GB1604368A
Application number: GB4148780A
Authority: GB
Original assignee: ARD TECH ASS ENG
Current assignee: ARD TECH ASS ENG
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-12-09

Description

(54) IMPROVEMENTS IN OR RELATING TO PRINTED CIRCUIT BOARD SUPPORT SYSTEM (71) We, A.R.D. TECHNICAL ASSIST ANCE AND ENGINEERING SERVICES INTER NATIONAL ANSTALT, of P.O. Box 34.613, 9490 Vaduz, Liechtenstein, a body corporate organised under the laws of Liechtenstein, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state- ment: The invention relates to a support system for one or more printed circuit boards.

According to the invention, there is provided a support system for one or more printed circuit boards, the system comprising a metal channel member having a centre wall and lateral walls, and means on the inner faces of the lateral walls for receiving at least one printed circuit board in a position extending transversely of the channel member between the lateral walls.

The invention is further described below by way of example with reference to the accompanying drawing, in which: Figure 1 is a sectional end view of a support system embodying the invention; and Figure 2 is a side view partially broken away of a circuit board module in combination with the support system of Figure 1.

As shown in Figure 1, the support system of the invention for amplifier or other circuit boards comprises a main channel member 100, which can be extruded or cast, having a centre wall or floor 101 and lateral or side walls 102, with a plurality of inwardly extending spaced parallel flanges 104 on each of the side walls 102. The flanges 104 on the two side walls are transversely aligned and so provide a plurality of supports on or between which circuit boards 10, can be secured. The boards 10 are provided with connector elements 11 at appropriate positions. A plurality of circuit boards received in overlying relationship on different pairs of the flanges 104 can readily be connected together in parallel by appro priate connector devices at their ends.

The channel member 100 provides elec trostatic shielding for the circuit com ponents on the circuit boards, and also provides a heat sink, with a channel be tween the lowermost circuit board and its floor 101. The undersurface of the floor is provided with ridges 105 to space the undersurface from a support surface on which the ridges rest and so provide for a cooling air flow beneath the undersurface.

In addition, there may be provided in the support system of the invention, air or other fluid cooling means. For example, as shown in figure 1, an array of tubing 106 is provided on the floor 101 of the main channel member 100 in good thermal contact therewith; the tubing can extend lengthwise of the member in parallel runs joined at alternate ends. Such an array can be duplicated if required or supple mented by a second array with runs ex tending transversely of the channel mem ber. The tubing ends of the tubing freely communicate with ambient atmosphere at positions which are preferably substantially vertically spaced. Heat from the amplifier circuit components collected by the heat sink arrangement of the support system promotes a conventional air flow through the tubing and thus a cooling effect. Such a cooling system provides a positive flow of air using only power derived from the waste heat which is to be removed.

The main channel member 100 can, as shown, be optionally associated with an auxiliary channel members 110 on one or on each side. The or each auxiliary channel member 110 can be extruded or cast, and has a floor 111 and walls 112 provided with transversely opposed pairs of internally projecting flanges 114. The or each channel member 110 may be in tegrally formed with the main channel as shown on the left of figure 1 or secured thereto in an electrically conductive manner, as shown on the right. Ridges similar to the ridges 105 can be provided on the or each auxiliary channel member.

The or each auxiliary channel member 110 can be employed to contain a power line and one or more power units for sup plying power to components on the board or boards 10 also if required. Instead, the channel member 110 could be employed to receive an output line transformer where the system board or boards 10 comprise an amplifier being employed, for example, for a public address system.

Another use for the auxiliary channels is for accommodating signal input and output lines, which may be in the form of printed circuit boards receiving on the flanges 114, and/or pre-amplifier and/or control means, and the outer side walls of an auxiliary channel used for this purpose can then be apertured to provide for the mounting of variable resistor or another appropriate control units.

If appropriate, the main channel member 100 and/or any such auxiliary channel member 110 associated with it can be enclosed by a cover 120 as shown to complete the heat sink function of the system; the cover, as well as the main and auxiliary channel member can be provided with ridges or other formations on the external surfaces to enlarge the heat radiating area.

The cover improves the electrostatic sheilding but desirably does not form an electrically conductive path right around the circuit elements contained therein to avoid formation of a closed current path. The system, or appropriate parts of it, can be of iron and arranged to provide electromagnetic shrouding of the electric circuit components contained therein if desired.

The flanges 104 and 114 can be used not only to support printed circuit boards but also conductive members to divide the interiors of the channel members into separately shielded or shrouded chambers.

It will be appreciated that the system of figure 1 does not require the boards 10 to be mounted on a mother board, connections to and between the boards 10 being made by way of connector devices. The system offers a compact arrangement of which one dimension, the vertical dimension in the position shown in the drawings, is particularly small compared with the others. The system can of course be employed in any orientation.

The invention also provides an amplifier circuit board module which can be assembled with the support system of figure 1, as shown in figure 2.

The circuit board module comprises a channel shaped member 140 which may again be extruded or cast having a centre or base wall 141 and lateral or side walls 142. Means is provided on the base wall 141 of the member 140 for supporting at least one circuit board 10 to extend generally parallel to the side walls 142. A plurality of the channel members 140 is arranged to be received on the upper pair of inwardly projecting flanges 104 of the main channel member 100, with the side walls 142, and thus the or each circuit board contained between them, extending at right angles to the axis of the main channel member 100. The circuit boards are preferably arranged to have their connecting terminals or other connecting devices located at the ends of the channel member 140 so connection can be made between them by means extending lengthwise of the main channel member.

In as far as the channel member 140 serves only to mount the circuit board or boards it contains in the system of figure 1, the channel member need not necessarily be of conductive material but could be of plastics material instead in some circumstances, particularly if the side walls of the channel member extend higher than as indicated in figure 2.

In a modified form of the circuit board module, the base wall is apertured, so that connection can be made to the or each circuit board 10 in the module by way of a mother board received on the flanges T04 of the main channel member 100.

In another modification of the circuit board module, the apertured base wall of the channel member itself supports a mother board 144 to which the circuit board 10 extending parallel to the side walls is connected. The arrangement is convenient when the module contains more than of the circuit boards 10. Connection between mother boards of adjacent modules can then be made within the channel formed by the circuit module base walls 141, and the floor of the main channel member 100.

It will be evident that the support system of the invention provides a universal construction and assembly system capable of incorporating integrated heat sink electrostatic shielding and electromagnetic shrouding. The system of the invention can be employed to eliminate the use of shielding wires within an amplifier or other device.

It serves to reduce the overall weight of such a device to improve the effectiveness of heat dissipation, to simplify the structure and thus to reduce tooling and engineering costs.

Reference is made to UK Application 25 796/78 (Serial No. 1604367) from which the present application was divided.

WHAT WE CLAIM IS: 1. A support system for one or more printed circuit boards, the system comprising a metal channel member having a centre wall and lateral walls, and means on the inner faces of the lateral walls for

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. The or each auxiliary channel member 110 can be employed to contain a power line and one or more power units for sup plying power to components on the board or boards 10 also if required. Instead, the channel member 110 could be employed to receive an output line transformer where the system board or boards 10 comprise an amplifier being employed, for example, for a public address system. Another use for the auxiliary channels is for accommodating signal input and output lines, which may be in the form of printed circuit boards receiving on the flanges 114, and/or pre-amplifier and/or control means, and the outer side walls of an auxiliary channel used for this purpose can then be apertured to provide for the mounting of variable resistor or another appropriate control units. If appropriate, the main channel member 100 and/or any such auxiliary channel member 110 associated with it can be enclosed by a cover 120 as shown to complete the heat sink function of the system; the cover, as well as the main and auxiliary channel member can be provided with ridges or other formations on the external surfaces to enlarge the heat radiating area. The cover improves the electrostatic sheilding but desirably does not form an electrically conductive path right around the circuit elements contained therein to avoid formation of a closed current path. The system, or appropriate parts of it, can be of iron and arranged to provide electromagnetic shrouding of the electric circuit components contained therein if desired. The flanges 104 and 114 can be used not only to support printed circuit boards but also conductive members to divide the interiors of the channel members into separately shielded or shrouded chambers. It will be appreciated that the system of figure 1 does not require the boards 10 to be mounted on a mother board, connections to and between the boards 10 being made by way of connector devices. The system offers a compact arrangement of which one dimension, the vertical dimension in the position shown in the drawings, is particularly small compared with the others. The system can of course be employed in any orientation. The invention also provides an amplifier circuit board module which can be assembled with the support system of figure 1, as shown in figure 2. The circuit board module comprises a channel shaped member 140 which may again be extruded or cast having a centre or base wall 141 and lateral or side walls 142. Means is provided on the base wall 141 of the member 140 for supporting at least one circuit board 10 to extend generally parallel to the side walls 142. A plurality of the channel members 140 is arranged to be received on the upper pair of inwardly projecting flanges 104 of the main channel member 100, with the side walls 142, and thus the or each circuit board contained between them, extending at right angles to the axis of the main channel member 100. The circuit boards are preferably arranged to have their connecting terminals or other connecting devices located at the ends of the channel member 140 so connection can be made between them by means extending lengthwise of the main channel member. In as far as the channel member 140 serves only to mount the circuit board or boards it contains in the system of figure 1, the channel member need not necessarily be of conductive material but could be of plastics material instead in some circumstances, particularly if the side walls of the channel member extend higher than as indicated in figure 2. In a modified form of the circuit board module, the base wall is apertured, so that connection can be made to the or each circuit board 10 in the module by way of a mother board received on the flanges T04 of the main channel member 100. In another modification of the circuit board module, the apertured base wall of the channel member itself supports a mother board 144 to which the circuit board 10 extending parallel to the side walls is connected. The arrangement is convenient when the module contains more than of the circuit boards 10. Connection between mother boards of adjacent modules can then be made within the channel formed by the circuit module base walls 141, and the floor of the main channel member 100. It will be evident that the support system of the invention provides a universal construction and assembly system capable of incorporating integrated heat sink electrostatic shielding and electromagnetic shrouding. The system of the invention can be employed to eliminate the use of shielding wires within an amplifier or other device. It serves to reduce the overall weight of such a device to improve the effectiveness of heat dissipation, to simplify the structure and thus to reduce tooling and engineering costs. Reference is made to UK Application 25 796/78 (Serial No. 1604367) from which the present application was divided. WHAT WE CLAIM IS:

1. A support system for one or more printed circuit boards, the system comprising a metal channel member having a centre wall and lateral walls, and means on the inner faces of the lateral walls for

receiving at least one printed circuit board in a position extending transversely of the channel member between the lateral walls.

2. A support system as claimed in claim 1 wherein the means on each lateral wall are arranged to support a printed circuit board to extend substantially parallel to the main channel member centre wall.

3. A support system as claimed in claim 1 or 2 wherein the means on each lateral wall comprise a plurality of parallel longitudinaly spaced flanges, each flange being aligned with and equi-spaced from the floor with a like flange on the other lateral wall.

4. A support system as claimed in claim 1, 2 or 3 having a cover member for the main channel member, the cover member being of electrically conductive or of plastics or other non-conductive material.

5. A support system as claimed in claim 1, 2, 3 or 4 having one auxiliary metal channel member extending along one or both lateral walls of the main channel member.

6. A support system as claimed in claim 5 wherein the or each auxiliary channel member is integral with the main channel member or electrically conductively connected therewith.

7. A support system as claimed in claim 5 or 6 wherein the or each auxiliary channel member has means for supporting therein at least one elongate printed circuit board.

8. A support system as claimed in claim 5, 6, or 7 having a cover member for the or each auxiliary channel member.

9. A support system as claimed in claim 8 as dependent on claim 4 wherein the cover member for the or each auxiliary channel member is integral with the cover member for the main channel member.

10. A support system as claimed in any preceding claim having cooling means associated with the centre wall of the main channel member.

11. A support system as claimed in claim 10 wherein the cooling means comprises an air duct through which cooling air flow is induced by convection.

12. A support system substantially as herein described with reference to Figure 1 of the accompanying drawing.

13. A support system as claimed in any preceding claim having received therein at least one printed circuit board module, the module comprising a channel member having a centre wall and lateral walls, and at least one circuit board received therein to extend substantially parallel to the lateral walls and to be spaced therefrom, the module lateral walls extending tranversely of the main channel member.

14. A support system as claimed in claim 13 having a plurality of the circuit boards side-by-side within the or each module, the spacings between the boards and the module lateral walls being substantially equal.

15. A support system as claimed in claim 13 or 14 wherein the or each circuit board in the or each module is connected to a mother board received in an aperture in the module centre wall.

16. A support system as claimed in claim 13 or 14 wherein the module centre wall is apertured to enable connection to be made therethrough to the or each circuit board in the module.

17. A support system as claimed in claim 13, 14, 15 or 16 wherein the module channel member is of electrically conductive material or of plastics or other electrically non-conductive material.

18. A support system substantially as herein described with reference to Figure 2 of the accompanying drawing.