Electronic conduction cooling clamp

• US 4,298,904 A
• Filed: 12/17/1979
• Issued: 11/03/1981
• Est. Priority Date: 12/17/1979
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Koenig, Philip C.
• Primary Examiner(s): Tolin, Gerald P.
• Application Number:
  US06/104,643
• Time in Patent Office: 687 Days
• Field of Search: 361/381, 361/382, 361/385-389, 361/399, 361/415, 174/16 HS, 211/41, 357/82, 165/80 R, 165/80 A, 165/80 B, 165/80 D
• US Class Current: 361/720
• CPC Class Codes: H05K 7/1404 by edge clamping, e.g. wedges
• CPC Class Codes: H05K 7/20545 Natural convection of gaseous coolant; Heat transfer by conduction from electronic boards

Abstract

Clamp means for securing a printed circuit board to a chassis or "cold wall" with improved heat transfer characteristics. The chassis, which acts as a heat sink, is provided with elongated slots which receive the opposite edges of a heat conductive metallic plate sandwiched between insulating printed circuit layers of the printed circuit card. Disposed within each slot is an elongated clamp which, when set, not only forces the heat conductive plate into contact with a first wall of the elongated slot but also exerts a force against, and is in abutting relationship with, a wall normal to the first wall. This maximizes the cross-sectional area of the path through which heat can flow from the heat conductive metallic plate to the chassis, thus improving the heat transfer characteristics.

Claims

1. A device comprising a clamp mounting an edge portion of a printed circuit board into a channel guide having interior opposing wall surfaces and an interconnecting wall surface, said device comprising:

an elongated bar assembly of rectangular cross-section and having lengthwise a series of end-to-end bar segments with a hole extending longitudinally therethrough;

a bolt having a head, a shank threaded at its end portion and being inserted through said hole in the elongated bar assembly;

said elongated bar assembly having end bar segments at each end thereof wherein said hole is parallel offset from the longitudinal centerline of each of said end bar segments;

one of said end bar segments being located at the head end of said bolt and having a hole diameter approximately equal to that of the bolt shank diameter for a close sliding fit;

the other of said end bar segments being located at the shank end of said bolt and having a threaded hole for screwing onto the threaded shank end portion of said bolt;

intermediate bar segments, between said head end bar segment and said shank end bar segment, wherein said hole is coaxial with the longitudinal centerline of said intermediate bar segments and of a substantially larger diameter than the shank diameter of said bolt extending therethrough;

said intermediate bar segments, comprising in alternate series, a first set and a second set of intermediate bar segments having end facing surfaces abutting along an inclined plane such that said first and second set of intermediate bar segments spread divergently apart with their longitudinal centerlines remaining parallel to the bolt axis upon screwing the bolt into said threaded shank end bar segment and drawing the end bar segments tightly together;

said first set of intermediate bar segments applying a force against said printed circuit board edge portion pressing it firmly against a first interior opposing wall surface of said channel guide and simultaneously bearing against the interconnecting wall surface of said channel guide;

said second set of intermediate bar segments bearing against a second interior opposing wall surface of said channel guide;

whereby said first set and said second set of intermediate bar segments provide a contact area with each of the interior wall surfaces of said channel guide thereby producing three thermal conductive paths between said printed circuit board edge portion and said channel guide.

2. A device comprising a clamp mounting an edge portion of a printed circuit board into a channel guide having interior opposing wall surfaces and an interconnecting wall surface, said device comprising:

a bolt;

an elongated bar assembly comprising a lengthwise series of bar segments, of rectangular cross-section, having a hole extending longitudinally therethrough of substantially larger diameter than the shank diameter of said bolt and being loosely supported on said bolt in an end-to-end relationship;

said bar segments comprising in alternate series, a first set and a second set of bar segments, and each set of bar segments having end facing surfaces contacting along planes inclined to the longitudinal axis of the shank of said bolt;

means for tightening said bolt to apply an end force to said first and second set of bar segments, to draw them together, producing a sliding motion between the end facing surfaces of the bar segments along said inclined planes, to spread said first and second sets of bar segments apart parallel and divergently from the longitudinal axis of said bolt shank;

said first set of bar segments pressing the edge portion of the printed circuit board against one of the interior opposing wall surfaces of the channel guide and simultaneously bearing against the interconnecting wall surface of said channel guide;

said second set of bar segments bearing against the other of the interior opposing wall surfaces of said channel guide; and

thereby, providing thermal conduction paths from the edge portion of the printed circuit board to the three interior wall surfaces of said channel guide.

3. A device comprising a clamp mounting an edge portion of a printed circuit board into a channel guide having interior opposing wall surfaces and an interconnecting wall surface, said device comprising:

a bolt;

an elongated bar assembly comprising a lengthwise series of bar segments, of rectangular cross-section, having a hole extending longitudinally therethrough of substantially larger diameter than the shank diameter of said bolt and being loosely supported on said bolt shank in an end-to-end relationship;

each of said bar segments having an end surface formed by a transverse plane oriented along a line bisecting opposite corner angles of the rectangular cross-section and inclined at an angle of approximately forty-five degrees to the longitudinal centerline of each of said bar segments;

the end surfaces of each of said bar segments being oppositely inclined to said angle of approximately forty-five degrees to the longitudinal centerline of each of said bar segments, forming a truncated equilateral triangle type of bar segment;

said elongated bar assembly comprising in alternate series, a first set and a second set of bar segments;

means for tightening said bolt to apply an end force to said first and second set of bar segments, to draw them together, producing a sliding motion between the end facing surfaces of the bar segments along said inclined planes to spread said first and second sets of bar segments apart divergently parallel from the longitudinal axis of said bolt shank;

said first set of bar segments pressing the edge portion of the printed circuit board against one of the interior opposing wall surfaces of the channel guide and simultaneously bearing against the interconnecting wall surface of said channel guide;

said second set of bar segments bearing against the other of the interior opposing wall surfaces of said channel guide;

thereby providing thermal conduction paths from the edge portion of the printed circuit board to the three interior wall surfaces of said channel guide.