Magnetic relay

• US 4,225,836 A
• Filed: 08/18/1978
• Issued: 09/30/1980
• Est. Priority Date: 08/18/1978
• Status: Expired due to Term

• Current Assignee: Continental Bank NA
• Original Assignee: C.P. Clare International N.V.
• Inventors: Geelen, Evrard, DeMaesschalck, Etienne
• Primary Examiner(s): Braun, Fred L.
• Application Number:
  US05/934,805
• Time in Patent Office: 774 Days
• Field of Search: 35/151, 35/153, 35/154, 29/622
• US Class Current: 335/153
• CPC Class Codes: H01H 2050/446 Details of the insulating support of the coil, e.g. spool, bobbin, former
• CPC Class Codes: H01H 50/44 Magnetic coils or windings
• CPC Class Codes: H01H 51/282 Constructional details not covered by H01H51/281
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

A magnetic relay having an electromagnetic coil with an open center extending lengthwise therethrough and an outer tube of magnetic material enclosing it lengthwise. A pair of radially expandable disks of magnetic material are positioned in the outer tube across the ends of the coil and a pair of inner tubes of magnetic material are positioned axially aligned with each other through the central openings in the disks and in the open center of the coil about a switch contact, e.g. a reed switch capsule. The adjacent ends of the inner tubes are spaced apart to form a gap adjacent the coacting ends of the switch contact. These inner tubes are of a size in the open center of the coil to pass freely through the central openings in the disks and of a larger size at the location of the disks such that these inner tubes urge the disks to expand radially into tight contact with the inside of the outer tube.

Claims

1. In a magnetic relay having an electromagnetic coil with an open center extending lengthwise therethrough and switch contact means having coacting ends disposed lengthwise in said open center of said coil, the improvement which comprises:

an outer tube of magnetic material enclosing said coil lengthwise;

a pair of radially expandable disks of magnetic material positioned in said outer tube, across each end of the coil, each disk having a central opening aligned with said open center of the coil; and

a pair of inner tubes of magnetic material positioned axially aligned with each other through said central openings in said disks and in said open center of said coil about said switch contact means with the adjacent ends of said inner tubes spaced apart to form a gap adjacent said coacting ends of said switch contact means, said inner tubes being of a size in said open center of said coil to pass freely through said central openings in said disks and of a larger size at the location of said disks whereby said inner tubes urge said disks to expand radially into tight contact with the inside of said outer tube.

2. The improvement according to claim 1 in which each said inner tube terminates at the outer end thereof at the location of one of said disks and in which said larger size at the location of said central opening of said disk is in the form of an outward flare at said outer end of said inner tube.

3. The improvement according to claim 2 in which each said disk comprises a pair of plates, each generally in the form of a circular segment, said plates being coplanar and disposed symmetrically with respect to each other and with the chordal portions thereof confronting whereby said central opening is in the form of a pair of confronting openings, one in each said plate at the center of the chordal portion thereof.

4. The improvement according to claim 3 which further includes a bobbin of non-magnetic material having flanged ends and an open center, said electromagnetic coil being positioned on said bobbin with said switch contact means and said inner tubes being positioned in the open center of said bobbin, and means defining a pair of coplanar circular segmental slots in each flanged end of said bobbin, said slots having a depth intercepting the open center of the bobbin, said plates forming the said disks being positioned in said segmental slots in the flanges of said bobbin.

5. The improvement according to any one of claims 1, 2, 3 or 4 in which said gap between the adjacent ends of said inner tubes has a predetermined axial length such that the ratio of said axial length to the diameter of the inner tubes is comprised in the range extending from about 0.45 to about 0.85 thereby to maximize the sensitivity of said switch contact means.

6. A method of assembling a magnetic housing for a magnetic relay having an electromagnetic coil with an open center extending lengthwise therethrough and switch contact means having coacting ends disposed lengthwise in said open center of said coil which comprises positioning an outer tube of magnetic material to enclose said coil lengthwise, positioning a radially expandable disk of magnetic material in said outer tube across each end of said coil, each disk having a central opening which is aligned with the open center of the coil, and inserting a pair of inner tubes of magnetic material, one at each end of said open center of said coil, with said tubes axially aligned with each other through said central openings of said disks, said inner tubes being sized along the length thereof to pass through said central openings and the outer ends thereof being enlarged whereby, as said inner tubes are positioned with their inner ends adjacent each other forming a gap therebetween and the outer ends of said inner tubes are received in said central openings, said outer ends urge said disks to expand radially into tight contact with the inside of said outer tube.