Fuse wire switch

• US 4,906,962 A
• Filed: 01/05/1989
• Issued: 03/06/1990
• Est. Priority Date: 01/05/1989
• Status: Expired due to Fees

• Current Assignee: Babcock University (Microchip Technology Incorporated)
• Original Assignee: Babcock University (Microchip Technology Incorporated)
• Inventors: Duimstra, Frederick A.
• Primary Examiner(s): Broome, H.
• Application Number:
  US07/293,623
• Time in Patent Office: 425 Days
• Field of Search: 337/239, 337/238, 337/240, 337/218, 337/219, 337/217, 337/143, 337/148, 335/194
• US Class Current: 337/239
• CPC Class Codes: H01H 37/767 Normally open
• CPC Class Codes: H01H 61/04 wherein the thermally-sensitive member is only heated directly

Abstract

A spring powered switching mechanism in which the energy required to complete switching is stored in a spring (or springs) which are constrained in a "cocked" or stressed condition by a fuse wire. The fuse wire has the characteristic of having a relative flat coefficient of resistivity over a large temperature range. The mechanism is operative to close (or open) electrical circuits permanently upon receipt of the appropriate electrical signal to the "fuse" or "bridge" wire which is caused to break as a result of the receipt of the electrical signal.

Claims

1. A spring powered switch mechanism comprising;

a first pair of electrically conductive terminals which are spaced apart from each other,

a second pair of electrically conductive terminals which are spaced apart from each other and from said first pair of electrically conductive terminals,

contact means adapted to be selectively moved into electrical contact with said first pair of electrically conductive terminals to effect electrical connection between said first pair of electrically conductive terminals via said contact means,

spring means adapted to selectively exert force on said contact means to move said contact means,

said spring means includes a leaf-spring which is selectively flexed to apply force to move said contact means,

said spring means further includes a coil spring which is flexed to apply a force to move said leaf-spring, and

a fusible link connected between said second pair of electrically conductive terminals,

said fusible link adapted to restrain said spring means and said contact means in a position separated from said first pair of electrically conductive termainals.

2. The mechanism recited on claim 1 wherein,

said fusible link is adapted to be broken by the application of a control signal thereto via said second pair of electrically conductive terminals.

3. The mechanism recited in claim 1 including,

supporting means for supporting said spring means.

4. The mechanism recited in claim 1 wherein,

said first pair of electrically conductive terminals include contact surfaces joined thereto.

5. The mechanism recited in claim 4 wherein,

said first pair of electrically conductive terminals are capable of carrying a current of up to 50 amperes.

6. The mechanism recited in claim 1 including,

housing means for enclosing the switch mechanism.

7. The mechanism recited in claim 6 including,

an inert gas included within said housing.

8. The mechanism recited in claim 2 wherein,

said contact means includes a V-shaped portion for selectively contacting said first pair of electrically conductive terminals.

9. The mechanism recited in claim 1 wherein,

said fusible link passes axially through said coil spring.

10. The mechanism recited in claim 1 including,

mounting means connected to said contact means,

said fusible link engages said mounting means to restrain said contact means.

11. The mechanism recited in claim 1 wherein,

said fusible link comprises a thin wire which can be selectively broken by application of an electrical signal to said second pair of electrically conductive terminals.

12. The mechansim in claim 3 wherein,

said support means provides a pair of end posts which support the ends of said leaf-spring.

13. The mechanism recited in claim 10 wherein,

said mounting means includes a support wire attached to said contact means and a ceramic spool mounted on said support wire.

14. The mechanism recited in claim 6 wherein,

said housing means includes a support header as the base thereof.

15. The mechanism recited in claim 14 wherein,

at least one terminal of each of said first and second pair of terminals is isolated from said header means by a glass-ceramic insulation bead.

16. The mechanism recited in claim 3 wherein,

said support means is a unitary bracket for supporting both said leaf-spring and said coil spring.

17. The mechanism recited in claim 3 wherein,

said coil spring is disposed between said support means and the middle of said leaf-spring in order to selectively apply force to said leaf-spring.