Heat sink and transistor retaining assembly

• US 5,450,284 A
• Filed: 02/17/1994
• Issued: 09/12/1995
• Est. Priority Date: 02/17/1994
• Status: Expired due to Fees

• Current Assignee: Spacelabs Medical Incorporated (OSI Systems Incorporated)
• Original Assignee: Spacelabs Medical Incorporated (OSI Systems Incorporated)
• Inventors: Wekell, William O.
• Primary Examiner(s): Thompson, Gregory D.
• Application Number:
  US08/198,136
• Time in Patent Office: 572 Days
• Field of Search: 174/16.3, 257/718, 257/719, 257/726, 257/727, 361/704, 361/707, 361/709-718, 361/722
• US Class Current: 361/710
• CPC Class Codes: H01L 2023/4031 Packaged discrete devices, e.g. to-3 housings, diodes
• CPC Class Codes: H01L 2023/4081 Compliant clamping elements not primarily serving heat-conduction
• CPC Class Codes: H01L 23/4006 with bolts or screws
• CPC Class Codes: H01L 23/4093 Snap-on arrangements, e.g. clips
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A heat sink and transistor retaining assembly for installation onto a printed circuit board. The assembly has a thermally conductive base plate forming a heat sink adapted to be disposed adjacent to the board, a first electric insulator attached to the base plate, a plurality of transistors positioned at predetermined positions against the first electric insulator so as to be electrically insulated from the base plate, a second electric insulator adjacent to the transistors with the transistors sandwiched between the insulators, and a resilient clamp attached to the base plate with the electric insulators and transistors positioned therebetween. The clamp has a plurality of retaining fingers that exert a retaining force on the transistors between the first and second insulators to retain the transistors in predetermined positions relative to the board. The assembly is secured together as a unit after its several components have been positioned in a fixture that supports and retains the component in predetermined positions.

Claims

1. A heat sink and transistor retaining assembly that is adapted to be installed onto a printed circuit board coupled to a source of electricity, comprising:

a heat sink having a bottom edge portion adapted to be disposed adjacent said printed circuit board when said heat sink projects perpendicularly from a surface of said printed circuit board, said heat sink having a planar mounting surface and being a thermally conductive material;

a first electric insulator mounted on said planar mounting surface of said heat sink said first electric insulator being thermally conductive;

a plurality of transistors positioned against said first electric insulator, whereby said transistors are electrically insulated from said heat sink, each of said transistors having electric leads that extend below said bottom edge of said heat sink and that are adapted to engage said printed circuit board, said transistors generating heat when the electricity is passed therethrough, whereby said heat passes through said first electric insulator to said heat sink and dissipates from said heat sink;

a second electric insulator positioned adjacent said transistors with said transistors sandwiched between said first and second electric insulators; and

a resilient clamp attached to said heat sink, said clamp having a resilient retaining member that exerts a retaining force on said transistors through said second electric insulator to retain said transistors between said first and second electric insulators in predetermined positions, whereby said transistors are supported in the predetermined positions prior to being connected to said printed circuit board, said resilient retaining member having a respective resilient retaining finger for each of said transistors, said retaining fingers being connected to a common support plate that is secured to said heat sink, said retaining fingers exerting said retaining force on said transistors.

2. The heat sink and transistor assembly of claim 1 wherein at least one of said clamp and heat sink has means for mounting said assembly onto said printed circuit board.

3. The heat sink and transistor retaining assembly of claim 1 wherein each of said transistors is supported in a selected one of the predetermined positions, the predetermined positions being at a same distance above the bottom edge of the heat sink.

4. The heat sink and transistor retaining assembly of claim 1 wherein each of said transistors is supported in a selected one of the predetermined positions, the predetermined positions being more than one distance above the bottom edge of the heat sink.

5. The heat sink and transistor retaining assembly of claim 1 wherein said heat sink has at least one fin.

6. The heat sink and transistor retaining assembly of claim 1 wherein said heat sink is aluminum.

7. The heat sink and transistor retaining assembly of claim 1 wherein said first and second electric insulators are plastic.

8. The heat sink and transistor retaining assembly of claim 1, further comprising alignment means connected to said heat sink and adapted to align said first electric insulator against said base plate.

9. A printed circuit board assembly comprising:

a printed circuit board having a plurality of lead apertures and at least one retaining aperture said printed circuit board being adapted to connect to a source of electricity;

a heat sink having a bottom edge portion adapted to be disposed adjacent said printed circuit board when said heat sink projects perpendicularly from a surface of said printed circuit board, said heat sink having a planar mounting surface and being a thermally conductive material;

a first electric insulator mounted on said planar mounting surface of said heat sink, said first electric insulator being thermally conductive;

a plurality of transistors positioned against said first electric insulator, whereby said transistors are electrically insulated from said heat sink, each of said transistors having electric leads that extend below said bottom edge of said heat sink and through said lead apertures in said printed circuit board, said transistors generating heat when the electricity is passed therethrough, whereby said heat passes through said first electric insulator to said heat sink and dissipates from said heat sink;

a second electric insulator positioned adjacent said transistors with said transistors sandwiched between said first and second electric insulators; and

a resilient clamp attached to said heat sink, said clamp having a resilient retaining member that exerts a retaining force on said transistors through said second electric insulator to retain said transistors between said first and second electric insulators in predetermined positions, whereby said transistors are supported in the predetermined positions prior to being connected to said printed circuit board, said resilient retaining member having a respective resilient retaining finger for each of said transistors, said retaining fingers being connected to a common support plate that is secured to said heat sink, said retaining fingers exerting said retaining force on said transistors.

10. The printed circuit board assembly of claim 9 wherein at least one of said clamp and heat sink has means engaging said printed circuit board at said at least one retaining aperture for mounting said assembly onto said printed circuit board.

11. The printed circuit board assembly of claim 9 wherein each of said transistors is supported in a selected one of the predetermined positions, the predetermined positions being at a stone distance above the bottom edge of the heat sink.

12. The printed circuit board assembly of claim 9 wherein each of said transistors is supported in a selected one of the predetermined positions, the predetermined positions being more than one distance above the bottom edge of the heat sink.

13. The printed circuit board assembly of claim 9 wherein said heat sink has at least one fin.

14. The printed circuit board assembly of claim 9 wherein said heat sink is aluminum.

15. The printed circuit board assembly of claim 9 wherein said first and second electric insulators are plastic.

16. The printed circuit board assembly of claim 9, further comprising alignment means connected to said heat sink and adapted to align said first electric insulator against said heat sink.

17. A heat sink and transistor retaining assembly that is adapted to be installed onto a printed circuit board coupled to a source of electricity, comprising:

a heat sink having a bottom edge portion adapted to be disposed adjacent said printed circuit board when said heat sink projects perpendicularly from a surface of said printed circuit board said heat sink having a planar mounting surface and being a thermally conductive material;

a first electric insulator mounted on said planar mounting surface of said heat sink, said first electric insulator being thermally conductive;

a plurality of transistors positioned against said first electric insulator, whereby said transistors are electrically insulated from said heat sink, each of said transistors having electric leads that extend below said bottom edge of said heat sink and that are adapted to engage said printed circuit board said transistors generating heat when the electricity is passed therethrough, whereby said heat passes through said first electric insulator to said heat sink and dissipates from said heat sink;

a second electric insulator positioned adjacent said transistors with said transistors sandwiched between said first and second electric insulators;

a resilient clamp attached to said heat sink, said clamp having a resilient retaining member that exerts a retaining force on said transistors through said second electric insulator to retain said transistors between said first and second electric insulators in predetermined positions, whereby said transistors are supported in the predetermined positions prior to being connected to said printed circuit board; and

alignment means connected to said heat sink and adapted to align said first electric insulator against said base plate.

18. The heat sink and transistor assembly of claim 17 wherein at least one of said clamp and heat sink has means for mounting said assembly onto said printed circuit board.

19. The heat sink and transistor retaining assembly of claim 17 wherein each of said transistors is supported in a selected one of the predetermined positions, the predetermined positions being at a same distance above the bottom edge of the heat sink.

20. The heat sink and transistor retaining assembly of claim 17 wherein each of said transistors is supported in a selected one of the predetermined positions, the predetermined positions being more than one distance above the bottom edge of the heat sink.

21. The heat sink and transistor retaining assembly of claim 17 wherein said heat sink has at least one fin.