SPRING-OPERATED FIELD STRENGTH MEASURING DEVICE IN AN ELECTROMAGNETIC-TYPE AMPEREMETER

• US 3,611,136 A
• Filed: 09/29/1969
• Issued: 10/05/1971
• Est. Priority Date: 09/29/1969
• Status: Expired due to Term

• Current Assignee: Shinobu Hirose, Tomosuke Ito
• Original Assignee: Shinobu Hirose, Tomosuke Ito
• Inventors: Ito, Tomosuke, Hirose, Shinobu
• Primary Examiner(s): Lynch, Michael J.
• Application Number:
  US04/861,931
• Time in Patent Office: 736 Days
• Field of Search: 324/127 24/241PS 294/16,28,100,116,117,104
• US Class Current: 324/127
• CPC Class Codes: H01F 38/30 Constructions

Abstract

A spring-operated field strength-measuring device in an electromagnetic-type amperemeter comprising a stationary core member fixedly mounted on the housing of said amperemeter, a movable core member pivotally mounted on said housing for movement toward and away from said stationary core member, an operation handle portion integrally formed with said movable core member, a cam portion integrally formed with said movable core member, and a spring-loaded cam-engaging member abutting against said cam portion, said cam portion including a cam surface which is adapted to increase its radius of curvature from the rotation axis of said movable core member toward the point of action of the spring of said spring-loaded cam-engaging member.

Claims

1. A magnetic field-strength-measuring device in an electromagnetic clamp-on-type amperemeter which comprises a housing, a stationary core member fixedly mounted at one end on said housing of said amperemeter;

a movable core member, said movable core member pivotally mounted at said same end on said housing as said stationary core;

said movable core member being integrally formed with a handle and a cam portion;

said handle being actuatable to move said movable core member away from said stationary core member from a closed position in which said members are in abutting relation to an open position in which said members are spaced apart, and a spring-loaded cam portionengaging means disposed in abutment against said cam portion, said cam portion including a first, concave cam surface and a second, cam surface the radius of curvature of which increases from the axis of rotation of said movable core member toward the point of abutment of said spring-loaded cam portion-engaging means as the movable core member is pivoted inward toward said closed position where the first cam surface locks the core members in abutting relation.

2. A magnetic field strength measuring device in an electromagnetic amperemeter as set forth in claim 1, in which said cam portion engaging means comprises a casing fixedly mounted on said housing, a rod slidably disposed within said casing, a spring disposed within said casing with one end anchored to one wall of the casing and the other end anchored to one end of said rod and a ball received at the other end of the rod and being urged to abut against said cam portion by said spring thereby to urge the movable core member toward said second position.

3. A magnetic field strength measuring device in an electromagnetic type amperemeter as set forth in claim 1, in which said core sections are normally in juxtaposed position.

4. A magnetic field strength measuring device in an electromagnetic type amperemeter as set forth in claim 1, in which said handle includes said cam portIon, said handle being pivotally mounted with said movable core member, said cam portion extending inward of said housing.

5. A magnetic field strength measuring device in an electromagnetic type amperemeter as set forth in claim 1, in which said core members include coating layers, the coating layer on one said core member extending short of said core member end, the said coating layer on said other core member extending beyond said core member end, said coating layers covering both said core members when said core members are normally juxtaposed.