Clamp type galvanometer

• US 4,283,677 A
• Filed: 05/18/1979
• Issued: 08/11/1981
• Est. Priority Date: 05/18/1979
• Status: Expired due to Term

• Current Assignee: Shoji Niwa
• Original Assignee: Shoji Niwa
• Inventors: Niwa, Shoji
• Primary Examiner(s): Karlsen, Ernest F.
• Application Number:
  US06/040,324
• Time in Patent Office: 816 Days
• Field of Search: 324/127, 324/129, 324/157, 336/84 M, 336/176
• US Class Current: 324/127
• CPC Class Codes: G01R 1/22 Tong testers acting as secondary windings of current transformers
• CPC Class Codes: G01R 15/12 Circuits for multi-testers , i.e. multimeters, e.g. for measuring voltage, current, or impedance at will

Abstract

A clamp type galvanometer comprising a current transformer constituted from a coil-wounded split iron core pivotally secured so that it can be opened or closed, a lever for opening or closing said split iron core, a meter assembly consisting of a pointer and graduations for indicating the output of said current transformer through a cut-over circuit in the measuring range, and a grip for actuating said cut-over circuit in the measuring range. The device is compactly housed in a case of a size portable with one hand.

Claims

1. A clamp type galvanometer, comprising:

(a) current transformer means (5) including a core assembly of laminated plates made of an alloy of about 78.5% nickel and about 21.5% iron, said core assembly being split to provide two half core segments (8), said segments being pivotally secured at one end and overlapping each other at the other end, a portion of each plate where a coil is to be wound being reduced in width;

(b) a coil (9) wound around each segment at such reduced width portion;

(c) a shield plate (10) disposed over each coil;

(d) a lever (14) for opening or closing the overlapping other end of said segments;

(e) a case wherein said one end of said segments are pivotally secured, said case being of a size carriable with one hand, said lever extending out of said case;

(f) a meter assembly (19) with a pointer and graduations for indicating the output of said current transformer means displayed on said case, and including first circuit means with current measuring means operatively coupled to said current transformer means (5) to indicate the output of said current transformer means with said pointer and graduations;

(g) a printed circuit (25) having shunt circuit means in said meter assembly for measuring various ranges of current;

(h) a circular switching knob (27) coupled to said shunt circuit means for operating said printed circuit so as to determine the measuring range being measured; and

,

(i) a lock bar (29) disposed for being in contact with or separate from said pointer with a second knob (33) for operating said lock bar, said second knob being at the side of the case.

2. A clamp type galvanometer according to claim 1, wherein graduations for voltage and graduations for resistance are provided in addition to graduations for amperage on the scale in the meter assembly, and a jack for measurement of voltage and a jack for measurement of resistance are provided in the case, with an attaching plug being screwed into each said jack to secure it in position.

3. A clamp type galvanometer as claimed in claim 1 having a looped hang strap allowing passage of a human hand and wrist is attached to the case.

4. A clamp type galvanometer as claimed to claim 3 including covers over said segments, said covers having each an inner side with a recession formed therein, said shield plates being disposed in the respective recessions, and bonding means bonding said shield plates to said covers.