US3793495A - Pressure switch with diaphragm formed of flexible compressible material containing discrete electrically conductive particles which make and break the circuit - Google Patents

Pressure switch with diaphragm formed of flexible compressible material containing discrete electrically conductive particles which make and break the circuit Download PDF

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Publication number
US3793495A
US3793495A US00329346A US3793495DA US3793495A US 3793495 A US3793495 A US 3793495A US 00329346 A US00329346 A US 00329346A US 3793495D A US3793495D A US 3793495DA US 3793495 A US3793495 A US 3793495A
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diaphragm
contact
contact member
electrically conductive
passage
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US00329346A
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A Heap
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Lucas Electrical Co Ltd
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Lucas Electrical Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/021—Composite material
    • H01H1/029—Composite material comprising conducting material dispersed in an elastic support or binding material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/34—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by diaphragm
    • H01H35/346—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by diaphragm in which the movable contact is formed or directly supported by the diaphragm

Definitions

  • a fluid pressure operated switch comprises an electrically conductive body having a passage therethrough, a diaphragm engaging a shoulder on the body around the passage and lying across the latter, and a contact plate spring biassed into engagement with the diaphragm.
  • the diaphragm is formed of a flexible, compressible material which becomes electrically conductive when compressed.
  • the pressure applied by the spring acts on a portion of the diaphragm lying against the shoulder and is normally sufficient to render that portion electrically conductive so that the contact plate is normally electrically connected with the body.
  • the pressure applied by the spring on the said portion of the diaphragm is reduced to an extent such that the diaphragm is no longer electrically conductive and the contact plate is electrically isolated from the body.
  • a fluid pressure operated switch in accordance with the invention comprises a body having a passage therethrough and at least a contact portion which is of conductive material, a diaphragm extending across said passage and formed of a flexible compressible material containing discrete particles of electrically conductive material which are brought into contact with one another to establish conductive paths through the material when the material is compressed, a contact member spring biased into engagement with said diaphragm so as to compress a portion of said diaphragm between the contact member and the contact portion of the body, the arrangement being such that the application of sufficient fluid pressure to said passage to overcome spring bias on the contact member deforms the diaphragm so that the portion thereof which is compressed between the contact member and the contact portion of the body is disengaged from the contact member so as to break the electrical connection between the contact member and the contact portion of the body.
  • the switch shown includes a body formed of an electrically conductive material, such as aluminium.
  • the body 10 has a passage 11 therethrough which terminates at a shoulder 12 defining a contact portion.
  • Mounted on the body is an insulating cap-shaped member 13 which carries a terminal 14 connected to a conductive contact disc 15 through the intermediary of a spring 16 which urges the contact member 15 towards the open end of the passage 11.
  • a diaphragm 17 Overlying the shoulder 12 on the body 10 is a diaphragm 17 formed of a known material consisting of discrete particles of a conductive material in a compressible matrix such that compression of the matrix between contact portion of the body and the contact member 15 will cause an electrical path to be established between said contacts only through the com pressed portion of the matrix.
  • the contact member 15 is of larger diameter than the passage 1 1 so that it overlies a portion of the shoulder 12 forming the contact portion of the body.
  • the spring 16 urges the contact member into engagement with the diaphragm 17 and compresses a portion of it overlying the contact portion of the body.
  • the cup-shaped member 13 has a counter-bore at its end which slidably receives the contact member 15.
  • the outer end of this counter-bore has a flared mouth 18 so that the diaphragm 17 is free outwardly of the contact member 15 to be displaced towards the terminal 14.
  • a fluid pressure operated switch comprising a body having a passage therein and at least a contact portion which is of conductive material, a diaphragm extending across said passage and formed of a flexible compressible material containing discrete particles of electrically conductive material which are brought into contact with one another to establish conductive paths through the material when the material is compressed, a contact member spring-biased into engagement with said diaphragm so as to compress a portion of said diaphragm between the contact member and the contact portion of the body, the arrangement being such that the application of sufficient fluid pressure to said passage to overcome spring bias on the contact member deforms the diaphragm so that the portion thereof which is compressed between the contact member and the contact portion of the body is disengaged from the contact member so as to break the electrical connection between the contact member and the contact portion of the body.

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  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
  • Push-Button Switches (AREA)

Abstract

A fluid pressure operated switch comprises an electrically conductive body having a passage therethrough, a diaphragm engaging a shoulder on the body around the passage and lying across the latter, and a contact plate spring biassed into engagement with the diaphragm. The diaphragm is formed of a flexible, compressible material which becomes electrically conductive when compressed. The pressure applied by the spring acts on a portion of the diaphragm lying against the shoulder and is normally sufficient to render that portion electrically conductive so that the contact plate is normally electrically connected with the body. When a sufficient pressure exists in the passage, the pressure applied by the spring on the said portion of the diaphragm is reduced to an extent such that the diaphragm is no longer electrically conductive and the contact plate is electrically isolated from the body.

Description

United States Patent 1191 Heap 1451 Feb. 19, 1974 [75] Inventor:
[73] Assignee: The Lucas Electrical Company, Limited, Birmingham, England 22 Filed: Feb. 5, 1973 21 Appl. No.: 329,346
Alec John Heap, Burnley, England [30] Foreign Application Priority Data Feb. 5, 1972 Great Britain 5476/72 [52] US. Cl. 200/83 B, 200/83 N, 338/42 [51] Int. Cl. H0lh 35/34, "016 9/06 [58] Field of Search.... 200/83 N, 83 B, 83 R, 83 V; 338/36, 42, 99
[56] References Cited UNITED STATES PATENTS 2,474,662 6/1949 Fuller 338/42 2,752,558 6/1956 Kane 338/42 X 3,394,345 7/1968 Thomas 200/83 V X 3,455,165 7/1969 Huet 338/42 X 3,509,296 4/1970 Harshman et al 338/99 X 3,573,725 4/1971 Shellhause 200/83 B X FOREIGN PATENTS OR APPLICATIONS 1,177,677 7/1957 France 338/42 OTHER PUBLICATIONS IBM Technical Disclosure, Vol. 6, No. 5, p. 47; October, 1963; Pneumatic to Electric Transducer by Meier.
Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney, Agent, or Firm-I-Iolman and Stern [5 7] ABSTRACT A fluid pressure operated switch comprises an electrically conductive body having a passage therethrough, a diaphragm engaging a shoulder on the body around the passage and lying across the latter, and a contact plate spring biassed into engagement with the diaphragm. The diaphragm is formed of a flexible, compressible material which becomes electrically conductive when compressed. The pressure applied by the spring acts on a portion of the diaphragm lying against the shoulder and is normally sufficient to render that portion electrically conductive so that the contact plate is normally electrically connected with the body. When a sufficient pressure exists in the passage, the pressure applied by the spring on the said portion of the diaphragm is reduced to an extent such that the diaphragm is no longer electrically conductive and the contact plate is electrically isolated from the body.
5 Claims, 1 Drawing Figure 1 PRESSURE SWITCH WITH DIAPHRAGM FORMED OF FLEXIBLE COMPRESSIBLE MATERIAL CONTAINING DISCRETE ELECTRICALLY CONDUCTIVE PARTICLES WHICH MAKE AND BREAK THE CIRCUIT This invention relates to a fluid pressure operated switch.
A fluid pressure operated switch in accordance with the invention comprises a body having a passage therethrough and at least a contact portion which is of conductive material, a diaphragm extending across said passage and formed of a flexible compressible material containing discrete particles of electrically conductive material which are brought into contact with one another to establish conductive paths through the material when the material is compressed, a contact member spring biased into engagement with said diaphragm so as to compress a portion of said diaphragm between the contact member and the contact portion of the body, the arrangement being such that the application of sufficient fluid pressure to said passage to overcome spring bias on the contact member deforms the diaphragm so that the portion thereof which is compressed between the contact member and the contact portion of the body is disengaged from the contact member so as to break the electrical connection between the contact member and the contact portion of the body.
An example of the invention is shown in the accompanying drawing which is a longitudinal cross-section through a switch according to the present invention.
The switch shown includes a body formed of an electrically conductive material, such as aluminium. The body 10 has a passage 11 therethrough which terminates at a shoulder 12 defining a contact portion. Mounted on the body is an insulating cap-shaped member 13 which carries a terminal 14 connected to a conductive contact disc 15 through the intermediary of a spring 16 which urges the contact member 15 towards the open end of the passage 11.
Overlying the shoulder 12 on the body 10 is a diaphragm 17 formed of a known material consisting of discrete particles of a conductive material in a compressible matrix such that compression of the matrix between contact portion of the body and the contact member 15 will cause an electrical path to be established between said contacts only through the com pressed portion of the matrix. The contact member 15 is of larger diameter than the passage 1 1 so that it overlies a portion of the shoulder 12 forming the contact portion of the body. The spring 16 urges the contact member into engagement with the diaphragm 17 and compresses a portion of it overlying the contact portion of the body. Thus, when there is no pressure applied in the passage 11, a conductive path is established between the terminal 14 and the body 10.
The cup-shaped member 13 has a counter-bore at its end which slidably receives the contact member 15. The outer end of this counter-bore has a flared mouth 18 so that the diaphragm 17 is free outwardly of the contact member 15 to be displaced towards the terminal 14. Thus, when a sufficient fluid pressure is applied to the passage 11 to overcome the biasing of the spring 16 the diaphragm 17 is deformed to a shallow cup shaped configuration with the contact member 15 engaging the centre portion of the diaphragm 17 but not the portion thereof overlying the shoulder 12.
It will be appreciated that when there is no pressure applied to the passage 1 1 the entire force applied to the contact member 15 by the spring 16 is absorbed through a narrow annular portion of the diaphragm l2 overlying the contact portion on the body. When the diaphragm is deformed, however, the force of the spring 16 is taken by the centre portion of the diaphragm, and insufficient pressure is applied to the diaphragm over the contact portion-on the body to compress the diaphragm sufficiently to cause conductive paths to be established through it.
I claim:
1. A fluid pressure operated switch comprising a body having a passage therein and at least a contact portion which is of conductive material, a diaphragm extending across said passage and formed of a flexible compressible material containing discrete particles of electrically conductive material which are brought into contact with one another to establish conductive paths through the material when the material is compressed, a contact member spring-biased into engagement with said diaphragm so as to compress a portion of said diaphragm between the contact member and the contact portion of the body, the arrangement being such that the application of sufficient fluid pressure to said passage to overcome spring bias on the contact member deforms the diaphragm so that the portion thereof which is compressed between the contact member and the contact portion of the body is disengaged from the contact member so as to break the electrical connection between the contact member and the contact portion of the body.
2. A switch as claimed in claim 1, wherein the contact portion of the body is provided by a shoulder therein against which the diaphragm abuts.
3. A switch as claimed in claim 2, wherein the diaphragm is lodged between the shoulder and an electrically insulating hollow member in which is disposed the contact member.
4. A switch as claimed in claim 3, wherein the hollow member carries a terminal electrically connected with the contact member via the spring which is lodged in the hollow member.
5. A switch as claimed in claim 3, wherein a portion of the hollow member surrounding the contact member is defined by a flared mouth which engages the diaphragm.

Claims (5)

1. A fluid pressure operated switch comprising a body having a passage therein and at least a contact portion which is of conductive material, a diaphragm extending across said passage and formed of a flexible compressible material containing discrete particles of electrically conductive material which are brought into contact with one another to establish conductive paths through the material when the material is compressed, a contact member spring-biased into engagement with said diaphragm so as to compress a portion of said diaphragm between the contact member and the contact portion of the body, the arrangement being such that the application of sufficient fluid pressure to said passage to overcome spring bias on the contact member deforms the diaphragm so that the portion thereof which is compressed between the contact member and the contact portion of the body is disengaged from the contact member so as to break the electrical connection between the contact member and the contact portion of the body.
2. A switch as claimed in claim 1, wherein the contact portion of the body is provided by a shoulder therein against which the diaphragm abuts.
3. A switch as claimed in claim 2, wherein the diaphragm is lodged between the shoulder and an electrically insulating hollow member in which is disposed the contact member.
4. A switch as claimed in claim 3, wherein the hollow member carries a terminal electrically connected with the contact member via the spring which is lodged in the hollow member.
5. A switch as claimed in claim 3, wherein a portion of the hollow member surrounding the contact member is defined by a flared mouth which engages the diaphragm.
US00329346A 1972-02-05 1973-02-05 Pressure switch with diaphragm formed of flexible compressible material containing discrete electrically conductive particles which make and break the circuit Expired - Lifetime US3793495A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB547672A GB1409783A (en) 1972-02-05 1972-02-05 Fluid pressure operated switch

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US3793495A true US3793495A (en) 1974-02-19

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US (1) US3793495A (en)
JP (1) JPS4888479A (en)
DE (1) DE2305300A1 (en)
FR (1) FR2170262B1 (en)
GB (1) GB1409783A (en)
IT (1) IT977166B (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899766A (en) * 1974-03-29 1975-08-12 Tyco Laboratories Inc Pressure transducer
US3935636A (en) * 1974-03-29 1976-02-03 Tyco Laboratories, Inc. Method of making a pressure transducer
US4083332A (en) * 1975-06-30 1978-04-11 Societe Anonyme Francaise De Ferodo Fitting of a fluid temperature switch in a wall
US5045829A (en) * 1990-02-23 1991-09-03 Hiroshi Kuramochi Pressure sensor utilizing extension type conductive rubber
US5619022A (en) * 1995-06-21 1997-04-08 Micro Pneumatic Logic, Inc. Pneumatic snap action switch

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2474662A (en) * 1945-12-19 1949-06-28 Fuller Reginald Cyril Electric pressure indicator
US2752558A (en) * 1953-04-22 1956-06-26 Ernest M Kane Electric transducer
FR1177677A (en) * 1956-08-27 1959-04-28 Bendix Aviat Corp Pressure converter
US3394345A (en) * 1965-09-17 1968-07-23 Edward M. Thomas Signal means for indicating residual hydraulic pressure in a brake system
US3455165A (en) * 1965-12-22 1969-07-15 Pierre Huet Pressure sensitive devices
US3509296A (en) * 1967-10-23 1970-04-28 Ncr Co Resilient variable-conductivity circuit controlling means
US3573725A (en) * 1969-06-25 1971-04-06 Gen Motors Corp Resilient accumulator reservoir with failure switch

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2474662A (en) * 1945-12-19 1949-06-28 Fuller Reginald Cyril Electric pressure indicator
US2752558A (en) * 1953-04-22 1956-06-26 Ernest M Kane Electric transducer
FR1177677A (en) * 1956-08-27 1959-04-28 Bendix Aviat Corp Pressure converter
US3394345A (en) * 1965-09-17 1968-07-23 Edward M. Thomas Signal means for indicating residual hydraulic pressure in a brake system
US3455165A (en) * 1965-12-22 1969-07-15 Pierre Huet Pressure sensitive devices
US3509296A (en) * 1967-10-23 1970-04-28 Ncr Co Resilient variable-conductivity circuit controlling means
US3573725A (en) * 1969-06-25 1971-04-06 Gen Motors Corp Resilient accumulator reservoir with failure switch

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
IBM Technical Disclosure, Vol. 6, No. 5, p. 47; October, 1963; Pneumatic to Electric Transducer by Meier. *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899766A (en) * 1974-03-29 1975-08-12 Tyco Laboratories Inc Pressure transducer
US3935636A (en) * 1974-03-29 1976-02-03 Tyco Laboratories, Inc. Method of making a pressure transducer
US4083332A (en) * 1975-06-30 1978-04-11 Societe Anonyme Francaise De Ferodo Fitting of a fluid temperature switch in a wall
US5045829A (en) * 1990-02-23 1991-09-03 Hiroshi Kuramochi Pressure sensor utilizing extension type conductive rubber
US5619022A (en) * 1995-06-21 1997-04-08 Micro Pneumatic Logic, Inc. Pneumatic snap action switch

Also Published As

Publication number Publication date
FR2170262B1 (en) 1976-11-05
IT977166B (en) 1974-09-10
AU5174773A (en) 1974-08-08
JPS4888479A (en) 1973-11-20
FR2170262A1 (en) 1973-09-14
GB1409783A (en) 1975-10-15
DE2305300A1 (en) 1973-08-16

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