United States Patent [19] [ii] Patent Number: 4,765,930
Mashimo et al. [45] Date of Patent: Aug. 23, 1988
[54] PRESSURE-RESPONSIVE VARIABLE ELECTRICAL RESISTIVE RUBBER MATERIAL
[75] Inventors: Satoshi Mashimo, Akashi; Susumu Nagayasu, Kobe; Yoshio Yamaguchi, Kobe; Torn Noguchi, Kobe; Masayoshi Nakajima, Ashiya; Hajime Kakiuchi, Itami; Kijuro Tanida, Ashiya, all of Japan
[73] Assignee: Mitsuboshi Belting Ltd., Kobe, Japan
[21] Appl. No.: 882,083
[22] Filed: Jul. 3, 1986
[30] Foreign Application Priority Data
Jul. 3, 1985 [JP] Japan 60-147160
Sep. 13, 1985 [JP] Japan 60-204020
Nov. 13, 1985 [JP] Japan 60-255652
[51] Int. a." H01B 1/06
[52] U.S. CI 252/511; 252/502;
252/503; 252/504; 252/506; 252/507; 252/508;
252/509; 524/495; 524/496; 524/440; 524/451;
524/445; 524/413; 524/401; 524/425; 524/430;
524/493
[58] Field of Search 252/511, 502, 509, 512,
252/518, 516, 503, 504, 506, 508, 513, 507, 520; 524/495, 496, 440, 401, 451, 445, 413, 425, 430,
493, 500
[56] References Cited
U.S. PATENT DOCUMENTS
3,875,434 4/1975 Harden et al 338/114
4,145,317 3/1979 Sado et al 252/512
4,292,261 9/1981 Kotani et al 252/511
4,302,361 11/1981 Kotani et al 252/511
4,495,236 1/1985 Obara et al 428/172
FOREIGN PATENT DOCUMENTS
2752540 1/1978 Fed. Rep. of Germany . 52-139989 11/1977 Japan .
OTHER PUBLICATIONS
Abstract—Japanese Patents Gazette, vol. 80, No. 24, Jul. 11, 1980, section CH-A85, ref. No. 80-42 324C/24 JP-A-55 58 504.
Chemical Abstracts, vol. 88, No. 20, May 15, 1978, p. 603 ref. No. 145162f; Columbus, Ohio—JP-A-52 139 989 (Inoue—Japan).
Primary Examiner—Josephine Barr
Attorney, Agent, or Firm—Wood, Dalton, Phillips,
Mason & Rowe
[57] ABSTRACT
A pressure-responsive variable electrical resistive rubber material including at least one inorganic filler selected from a group consisting of conductive carbon black, short fibers of nonmetallic inorganic material, powder, and whiskers. The filler is dispersed in a matrix formed of an electrically insulative rubber. The rubber material exhibits a gradually reducing resistance value as a gradually increased pressing force is applied thereto. The rubber material provides a wide range of relationship between the applied force and the electrical resistance thereof. The rubber material is adapted for use as a pressure sensor having excellent fatigue creep resistance.
9 Claims, 4 Drawing Sheets
