US Patent No. 5,414,219

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Issue Date: 05/09/1995

Abstract: A circuit control device includes two intermating foil pads separated from one another by a narrow gap having a maximum dimension of 0.006 inches. A circuit path having one side connected to one of the pads and a second side connected to the other of the pads is selectively closed and opened by solder application and removal operations. Interdigitated, triangular fingers which are intermated to form the device ensure the formation of acutely angled junctures along the gap to ensure solder bridging of the gap. Emergency control elements are coupled to the circuit control device to permit control of an associated circuit path if the circuit control device itself fails. In that event, an emergency control device is coupled to the emergency control elements to control opening and closing of the circuit path.

What is claimed is:
1. A circuit control device for a printed circuit board comprising:
a first foil pad secured to the circuit board and electrically connected to a first side of an electrical circuit to be selectively opened and closed by said circuit control device; and
a second foil pad secured to the circuit board and electrically connected to a second side of said electrical circuit to be selectively opened and closed by said circuit control device, said first and second foil pads being separated from one another by a gap which is bridged by solder during an automated solder processing of said printed circuit board to close said electrical circuit, said circuit control device being opened by removal of said solder and reclosed by replacement of said solder.

2. A circuit control device for a printed circuit board as claimed in claim 1 wherein said first and second foil pads are sized to remain secured to said printed circuit board through a plurality of soldering and desoldering operations.

3. A circuit control device for a printed circuit board as claimed in claim 2 wherein said gap is a maximum of 0.006 of an inch.

4. A circuit control device for a printed circuit board as claimed in claim 2 wherein said first and second foil pads form interdigitated portions which are separated from one another by said gap such that said interdigitated portions are bridged by solder during an automated solder processing of said printed circuit board to close said electrical circuit.

5. A circuit control device for a printed circuit board as claimed in claim 2 wherein said first and second foil pads form juxtaposed fingers which are separated from one another by said gap such that said juxtaposed fingers are bridged by solder during an automated solder processing of said printed circuit board to close said electrical circuit.

6. A circuit control device for a printed circuit board as claimed in claim 2 wherein said first and second foil pads comprise buses separated from one another by interdigitated fingers alternately extending from said buses, said fingers being separated from one another by said gap such that said interdigitated fingers are bridged by solder during an automated solder processing of said printed circuit board to close said electrical circuit.

7. A circuit control device for a printed circuit board as claimed in claim 2 wherein said first foil pad comprises a first bus and said second foil pad comprises a second bus, said foil pads each further comprising at least one finger extending therefrom and pointing toward the other foil pad, said fingers being separated from one another and from the foil pads which they face by said gap.

8. A circuit control device for a printed circuit board as claimed in claim 7 wherein said fingers are generally triangular in shape and connected to their corresponding bus by a triangle vertex.

9. A circuit control device for a printed circuit board as claimed in claim 2 further comprising emergency control elements electrically connected to said first and second foil pads for receiving an emergency control device for electrically connecting said first side of said electrical circuit to said second side of said electrical circuit.

10. A circuit control device for a printed circuit board as claimed in claim 9 wherein said emergency control elements comprise:
a first conductor receiving pad connected to said first foil pad for receiving a first end of an emergency control device; and
a second conductor receiving pad connected to said second foil pad for receiving a second end of an emergency control device.

11. A circuit control device for a printed circuit board as claimed in claim 10 wherein said emergency control device comprises an electrically conducting strap.

12. A circuit control device for a printed circuit board as claimed in claim 2 wherein said gap defines at least one angled juncture to ensure solder bridging between said first and second foil pads.

13. A circuit control device for a printed circuit board as claimed in claim 12 wherein at least one of said at least one angled juncture defines an acute angle.

14. A device for opening and closing a circuit path on a printed circuit board, said device comprising:
a first foil pad connected to a first side of the circuit path to be opened and closed by said device; and
a second foil pad connected to a second side of the circuit path to be opened and closed by said device, said first and second foil pads being separated by a gap which is bridged by solder to close the circuit path and cleared of solder to open the circuit path.

15. A device for opening and closing a circuit path on a printed circuit board as claimed in claim 14 wherein said first and second foil pads are sized to remain secured to said printed circuit board after a plurality of soldering and desoldering operations.

16. A device for opening and closing a circuit path on a printed circuit board as claimed in claim 15 wherein said gap defines at least one sharply pointed juncture to ensure solder bridging between said first and second foil pads.

17. A device for opening and closing a circuit path on a printed circuit board as claimed in claim 16 wherein:
said first foil pad defines a first bus and at least one generally triangular peninsular area connected to said first bus by a vertex of said peninsular area of said first foil pad such that it expands as it extends from said first bus; and
said second foil pad defines a second bus and at least one generally triangular peninsular area connected to said second bus by a vertex of said peninsular area of said second foil pad such that it expands as it extends from said second bus, said at least one generally triangular peninsular areas of said first and second buses being formed to interengage with one another such that said gap is formed between said triangular peninsular areas.

18. A device for opening and closing a circuit path on a printed circuit board as claimed in claim 17 further comprising emergency control elements electrically connected to said first and second foil pads for receiving an emergency control device for electrically connecting said first side of said electrical circuit to said second side of said electrical circuit.

19. A device for opening and closing a circuit path on a printed circuit board as claimed in claim 18 wherein said emergency control elements comprise:
a first conductor receiving pad connected to said first foil pad for receiving a first end of an emergency control device; and
a second conductor receiving pad connected to said second foil pad for receiving a second end of an emergency control device.

20. A device for opening and closing a circuit path on a printed circuit board as claimed in claim 17 wherein said gap is a maximum of 0.006 of an inch.