MAGNETIC TIME DELAY SWITCH

• US 3,602,851 A
• Filed: 04/02/1970
• Issued: 08/31/1971
• Est. Priority Date: 04/02/1970
• Status: Expired due to Term

• Current Assignee: John R. Wiegand
• Original Assignee: John R. Wiegand
• Inventors: Wiegand, John R.
• Primary Examiner(s): Gilheany, Bernard A.
• Assistant Examiner(s): Envall, Jr., R. N.
• Application Number:
  US05/025,195
• Time in Patent Office: 516 Days
• Field of Search: 317/133 335/146,151,154,208 336/179,73,75 338/183
• US Class Current: 335/146
• CPC Class Codes: H01H 51/281 Mounting of the relay; Encapsulating; Details of connections

Abstract

A magnetic reed switch comprises an insulative housing in which are laterally spaced magnetic reeds. A coil of magnetic wire is wound around the housing. An adjustable clamp encircles the coil. The reeds, coil and clamp can be connected in a circuit to perform a time delay switching function which is variable over a wide range by adjustably positioning the clamp.

Claims

1. A time delay switching device, comprising a cylindrical insulative support;

a helical coil of magnetic wire wound on said support;

said coil wire composed of material which loses its magnetic permeability upon heating a pair of flexible magnetic reeds secured to opposite ends of said support and extending longitudinally inside said support, said reeds having inner overlapping laterally spaced free inner ends, said reeds having outer ends extending outwardly of opposite ends of said cylindrical support, the outer end of one reed being connected to one end of said coil, the other end of said coil being free; and

a conductive member mounted on said support and slidable along said coil in contact therewith, and means for connecting said conductive member and the outer end of the other one of said reeds is series with a source of electrical voltage and a resistive load, whereby momentary electrical connection of the outer ends of said reeds will pass electrical current through a part of said coil to generate a magnetomotive force, which causes said inner ends of the reeds to contact each other, and whereby opening said electrical connection will leave said inner ends of the reeds contacting each other for a certain time duration while power is supplied to said load, whereupon said magnetomotive force will decrease due to current through said coil, which causes heating thereof, until the contacting inner ends of the reeds separate and cut off the power supplied to said load.

2. A time delay switching device as defined in claim 1, further comprising a switch having normally open contacts respectively connected to the outer ends of the reeds, whereby closure of said switch to close said contacts establishes said electrical connection between the outer ends of the reeds.

3. A time delay switching device as defined in claim 2, wherein said switch is a manually operable pushbutton switch.

4. A time delay switching device as defined in claim 1, wherein said conductive member has the form of a cylindrical clamp encircling said support and coil in contact with the coil, whereby said certain time duration is determined by the position of said clamp axially along the coil.

5. A time delay switching device as defined in claim 4 further comprising a switch having normally open contacts respectively connected to the outer ends of the reeds, whereby closure of said switch to close said contacts establishes said electrical connection between the outer ends of the reeds.

6. A time delay switching device as defined in claim 1, further comprising an electrical voltage source and a resistive load connected in series circuit with each other, said circuit having two terminals respectively connected to said conductive member and said outer end of the other one of the reeds, said coil having an impedance which is smaller that that of said load so that substantially all of the power generated by said voltage source is consumed in said load.

7. A time delay switching device as defined in claim 6, wherein said voltage source supplies alternating current to the load and coil, said device further comprising a permanent magnet movable disposed adjacent said coil for generating a magnetomotive force field between the spaced inner ends of the reeds when the magnet is momentarily disposed sufficiently close to the coil to cause said inner ends of the reeds to contact each other.

8. A time delay switching device as defined in claim 5, further comprising an electrical voltage source and a resistive load connected in series circuit with each other, said circuit having two terminals respectively connected to said clamp and the outer end of said other one of the reeds, said coil having an impedance which is smaller than that of said load so that substantially all of the power generated by said voltage source is consumed in said load.

9. A time delay switching device as defined in claim 8, wherein said switch is a manually operable pushbutton switch.

10. A time delay switching device as defined in claim 9, wherein said voltage source supplies alternating current to the load and coil, said device further comprising a permanent magnet movable disposed adjacent said coil for generating a magnetomotive force field between the spaced inner ends of the reeds when the magnet is momentarily disposed sufficiently close to the coil to cause said inner ends of the reeds to contact each other.