Method and apparatus for isolating electronic boards from shock and thermal environments

• US 5,285,559 A
• Filed: 09/10/1992
• Issued: 02/15/1994
• Est. Priority Date: 09/10/1992
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Sundstrand Corporation (Rtx Corporation)
• Inventors: Thompson, Craig, Eakin, Lawrence L.
• Primary Examiner(s): Arbes, Carl J.
• Application Number:
  US07/943,047
• Time in Patent Office: 523 Days
• Field of Search: 29/841, 29/840, 29/832, 174/16.3, 257/697, 206/334, 206/523
• US Class Current: 29/841
• CPC Class Codes: H05K 5/021 specially adapted for data recorders, e.g. for flight recorders
• CPC Class Codes: H05K 5/0213 Venting apertures; Constructional details thereof
• CPC Class Codes: H05K 7/1417 having securing means for mounting boards, plates or wiring boards H05K7/1461 takes precedence
• CPC Class Codes: Y10T 29/49146 with encapsulating, e.g., potting, etc.

Abstract

A method and apparatus for isolating electronic devices from mechanical shock and thermal environments utilizes a metal outer protective shell surrounding the electronic device to be protected. Interposed between the protective shell and the electronic device are a thermal insulating layer, a layer of phase change material and a layer of mechanical shock absorbent material.

Claims

1. A method of isolating an electronic device from mechanical shock and thermal environments, comprising the steps of:

providing a mass of wax-like material having a high heat of fusion for absorbing a substantial quantity of heat before rising above a critical temperature limit, said mass taking the form of two pre-formed sections, one of said sections having an accessible cavity formed therein;

filling said cavity with a fluid that subsequently cures into a solid having a rubber-like consistency;

placing said electronic device into the fluid-filled cavity;

assembling said two sections to render the cavity inaccessible;

applying heat insulating material around an outer surface of said mass of wax-like material for minimizing heat transfer to said electronic device; and

surrounding said heat insulating material with a metal shell for minimizing impact forces directed toward said memory device from outside said shell.

2. The method of claim 1, including the step of:

curing said fluid to form a resilient layer of shock resistant material for protecting said memory device against mechanical shock forces.

3. The method of claim 1, wherein:

said fluid is a silicone rubber of a type that cures in time to form a layer of rubber-like consistency.

4. The method of claim 3, wherein:

said silicone rubber has a non-adhesive property after curing so as to be readily peeled away from said electronic device.

5. The method of claim 3, including the step of:

curing said silicone rubber for a period of approximately twenty-four hours after said cavity has been filled.

6. The method recited in claim 5, wherein said silicone rubber is cured at room temperature.

7. A method of isolating a heat and mechanical shock sensitive device from heat and mechanical shock, comprising:

pre-forming a heat sink from a quantity of material having a high heat of fusion into a structure having a cavity capable of receiving said device;

filling said cavity with a fluid that is transformed over time to a solid having a resilient, shock absorbing consistency;

placing said device into said fluid; and

closing said cavity.

8. The method recited in claim 7 further including surrounding said heat sink with heat insulating and physical penetration resistant material.