Capacitor for measuring forces

• US 4,370,697 A
• Filed: 11/03/1980
• Issued: 01/25/1983
• Est. Priority Date: 01/21/1977
• Status: Expired due to Term

• Current Assignee: National City Bank (The PNC Financial Services Group, Inc.)
• Original Assignee: Semperit AG
• Inventors: Kastner, Josef, Haberl, Rainer
• Primary Examiner(s): Goldberg, Elliot A.
• Application Number:
  US06/203,102
• Time in Patent Office: 813 Days
• Field of Search: 361/283, 117/210 C
• US Class Current: 361/283.1
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G08B 13/26 by proximity of an intruder causing variation in capacitance or inductance of a circuit

Abstract

A capacitor comprising at least two electrodes separated from one another by an elastic dielectric for measuring forces acting upon one of the electrodes--the so-called measuring electrode--by detecting the resultant change in capacitance. The dielectric comprises a web having at least at one face thereof protruding nap-shaped protuberances defining a hollow space which is at a reduced pressure in relation to the external pressure.

Claims

1. A capacitor for measuring external pressure comprising:

a pair of electrically conductive electrodes;

an elastomeric dielectric comprising a web arranged between said electrodes;

seal means for sealing said elastomeric dielectric; and

said web having at least at one face thereof protruding nap-shaped protuberances defining a hollow space which is at a reduced pressure in relation to the external pressure.

2. The capacitor as defined in claim 1, wherein:

all of the regions around the protuberances communicate with one another to define said hollow space at which the same pressure conditions prevail.

3. The capacitor as defined in claim 1, wherein:

said elastomeric dielectric comprises a web having protuberances extending from both faces thereof.

4. The capacitor as defined in claim 1, wherein:

said protuberances are of substantially cylindrical configuration.

5. The capacitor as defined in claim 1, wherein:

said protuberances are of substantially conical configuration.

6. The capacitor as defined in claim 1, wherein:

said protuberances are of substantially pyramid like configuration.

7. The capacitor as defined in claim 1, wherein:

said protuberances are essentially uniformly distributed.

8. The capacitor as defined in claim 1, wherein:

the height of the protuberances amounts to approximately two-thirds of the thickness of the dielectric.

9. The capacitor as defined in claim 1, wherein:

the pressure in the hollow space formed by recesses between the nap-like protuberances and one of the electrodes is in the order of about 0.4 to 0.7 bar.