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Publication numberUS3636289 A
Publication typeGrant
Publication dateJan 18, 1972
Filing dateOct 20, 1969
Priority dateOct 20, 1969
Publication numberUS 3636289 A, US 3636289A, US-A-3636289, US3636289 A, US3636289A
InventorsPossell Clarence R
Original AssigneePossell Clarence R
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Differential fluid pressure actuated electrical switch
US 3636289 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent Possell [451 Jan. 18,1972

[72] inventor: Clarence R. Possell, 4842 Viane Way, San

Diego, Calif. 92110 22 Filed: Oct. 20, 1969 211 Appl.No.: 867,437

[52] [1.8. Ci. ..200/83 D, 92/34, 92/43, 200/83 B [51] Int. Cl. ..l-i0lh 35/32, F01b 19/04, F16j 3/00 [58] Field of Search ..200/83 D, 83.2 B, 83 C, 81.5;

[56] References Cited UNITED STATES PATENTS 2,427,426 9/1947 Swenson et al. ..200/83.31 X 2,557,929 6/1951 Baak ..200/83.31 X 2,658,392 10/1953 Vannah.... ZOO/83.31 UX 2,685,305 8/1954 Woods ..92/34 X 2,751,457 6/1956 Donaldson... ZOO/83.31 X 2,811,925 11/1957 Crookston ...92/34 X 3,187,639 6/1965 Kelly et al.... ..92/47 2,961,507 11/1960 l-liggs ..200/83.3

FOREIGN PATENTS OR APPLICATIONS 145,323 7/1920 GreatBritain ..92/91 543,922 3/1942 GreatBritain ..200/83.3i

Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney-William C. Babcock [57] ABSTRACT A differential fluid pressure actuated electrical switch that includes first and second resilient hollow deformable bodies, the interiors of which are connected to first and second sources of fluid at variable pressures, with said first source normally being at a higher fluid pressure than that in said second source. Parallel first and second force-exerting members project from said bodies, and bear against an elongate, movable actuator, which actuator when moved in a first direction, moves a spring-actuated member of an electrical switch from a first to a second position to either open or close said switch. The actuating member is moved from said first to said second position only when the pressure of fluid in said second body is at a predetermined, elevated pressure differential relative to the fluid in said first body.

1 Claims, 6 Drawing Figures PATENTEUJANIBIHH 35636289 FIG. Z


CLARENCE E. P035544 flrrole/var DIFFERENTIAL FLUID PRESSURE ACTUATED ELECTRICAL SWITCH- BACKGROUND OF THE INVENTION sure actuated electrical switch of a high degree of reliability has been available for opening or closing an electric circuit. The present invention provides a differential fluid pressure actuated electrical switch which overcomes numerous operational disadvantages found in prior art devices of this type.

SUMMARY OF THE INVENTION A differential fluid pressure actuated electrical switch in which first and second toroidal, hollow resilient bodies are connected to first and second sources of fluid under variable pressures. First and second parallel force-exerting members project from the first and second bodies and bear against a movable actuator. When the actuator is moved in a first direction it in turn moves a spring-loaded actuating member of an electric switch from a first to a second position.

The actuator moves said actuating member from the first to the second position, only when the fluid in the second body is at a predetermined elevated pressure differential relative to the pressure of fluid present in the first body.

A major object of the present invention is to provide a compact, lightweight differential fluid pressure actuated electrical switch of simple mechanical structure, that is temperature stable, has a high degree of reliability in operation, and that requires a minimum of maintenance attention.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view of a first form of differential fluid pressure actuated electrical switch;

FIG. 2 Ba longitudinal cross-sectional view of the switch shown in FIG. 1, taken on the line 2-2 thereof;

FIG. 3 is a transverse cross-sectional view of the switch, taken on the line 3-3 of FIG. 2;

FIG. 4 is an enlarged, transverse cross-sectional view of one of the resilient fluid-pressure deformable bodies used in the actuation of the switch;

FIG. Sis a fragmentary, transverse cross-sectional view of the switch shown in FIG. 2, taken on the line 5-5 thereof; and

FIG. 6 is a longitudinal cross-sectional view of a second form of fluid-actuated electrical switch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A differential fluid pressure actuated switch A is shown in perspective in FIG. 1, and in structural detail in FIGS. 2-5, which includes an electrical connector 8 of conventional design. A housing B is provided that is preferably cylindrical,

A slotted first protuberance 34 is formed at the junction of arms 16 and 18, with the protuberance serving to support a thin elongate metallic member 36 that is stiff but somewhat resilient. An elongate rigid actuator 38 is transversely positioned in housing B, forwardly of frame C. A slotted second protuberance 40 extends rearwardly from substantially the center actuator 38, with the second protuberance engaging the forward end of member 36 to support the actuator therefrom.

A tapped bore 42 (FIG. 2) extends through actuator 38 adjacent arm 16. Bore 42 is engaged by a screw 44 which serves as a first force-receiving member. A lock nut 46 serves to hold the screw 44 in a desired position relative to the actuator 38. A second force-receiving member 48 is mounted on the actuator 38 adjacent to the switch 24, and projects forwardly from the actuator.

A front piece D is provided that includes a square or rectangular mounting plate 50 (FIG. I) in which a number of screw- 7 receiving openings 52 are formed and in spaced relationship. First and second bosses 54 and 56, respectively, extend forwardly from the plate 50, and first and second fluid passages 54a and 56a, respectively, are formed therein. A grooved circular extension 58 extends rearwardly from the mounting plate 50, with this extension supporting a resilient O-ring 60, as shown in FIG. 2. The extension 58 and O-ring 60 are of such diameter as to snugly and slidably engage the side wall 10 adjacent to the open end 12. Front piece D and housing B are removably secured together by conventional means (not shown).

First and second toroidal hollow bodies 62 (FIG. 2) are mounted in the interior of the housing B and located in transversely spaced relationship. Each body 62 includes flat forward and rear central portions 63 and 64, respectively, as shown in FIG. 4. A stiff externally threaded tube 65 is welded to each forward portion 63 and a longitudinally extending bore 66 is formed in each of these tubes that is in communication with the interior of one of the bodies 62. The threaded tubes 65 engage the rear tapped portions of the passages 54a and 56a to place the interiors of the bodies 62 in communication therewith. The tubes 65 are sufficiently stiff as to serve to support the bodies 62 from the front piece D.

A force-imparting member 68 projects rearwardly from the central portion of the first body 62, 64, and member 68 is in longitudinal alignment with the force-receiving screw 44. A second force-imparting member 70 projects from the rear portion 64 of the second body 62, with the member 70 being in longitudinal alignment with the force-receiving member 48. The device is temperature stable. Any variation in temperature results in equal expansion or contraction of the two bodies 62, and as a result such variations cause no differential in the forces exerted by members 68 and 70 on member 48 and screw 44.

comprising a continuous sidewall 10 having a first open end l2, and a second closed end 14 in which the connector 8 is supported.

A cross-shaped frame C is disposed in the rear interior of housing B. Frame C comprises an upwardly extending first arm 16, a second downwardly extending arm 18, and two oppositely extending third and fourth arms 20 and 22. A forwardly extending electric switch 24 is supported on the lower free end of second arm 18, as shown in FIG. 2 and 3.

A spring-loaded actuating member 26 extends forwardly from switch 24, and normally occupies a first forward position (FIG. 2). First, second, and third electrical conductors 28, 30, and 32 lead from switch 24 and are connectedto parallel, spaced pin-receiving sockets supported in fixed positions in connector 8.

A bore 72 extends through the arm 16 and a screw 74 extends therethrough, which screw supports a generally U- shaped stop 76 provided on the forward end thereof. Two locknuts 78 permit the screw 74 and stop 76 to be located at a desired adjusted position relative to the arm 16. The switch 24 is of a type, which when a pronged jack forming a part of an electric circuit (not shown) engage sockets 28a and 30a in connector 8, and the actuating member 26 is in the first position, as shown in FIG. 2, the electric switch 24 maintains the circuit in an open condition. However, if the sockets 30a and 320 are engaged by a pronged jack fonning a part of an electric circuit (not shown) and the actuating member 26 is in the first position (FIG. 2), the switch is closed and completes the circuit.

The source of fluid (not shown) connected to the passage 54a is normally at a pressure higher than that of the source of fluid connected to the passage56a. The pressure of the fluid in the first body 62 longitudinally defonns the same and moves the first force-imparting member 68 rearwardly to exert a force on the force-receiving screw 44. Due to the force received by screw 44, the actuator 38 is moved until a first free end 38a thereof contacts a first surface 760 defined in the stop 76.

Should the pressure on fluid supplied to the second passage 56a rise above the fluid pressure in the first passage 54a and first body 62, the second body will deform longitudinally. Longitudinal deformation of second body 62 results in rearward movement of the second force-exerting member and pivoting the actuator 38 in a counter clockwise direction (FIG. 2). This pivotal movement of actuator 38 causes the actuating member 26 to be moved from a first to a second position to pen or close switch 24. Pivotal movement of actuator 38 in a counter clockwise direction is limited by the end 380 of actuator 38 when it contacts surface 76b of stop 76. Thus, no matter how high the pressure of fluid in second body 62, the force-imparting member 70 cannot move rearwardly to the extent that it pivots actuator 38 to a degree that an excessive force is exerted on actuating member 26 of switch 24.

Two elongate, laterally spaced posts 80 extend rearwardly from extension 58 and are in longitudinal alignment with arms and 22, the rear surfaces of the posts abut against the forward surfaces of the arms 20 and 22. Screws 82, as may be seen in FIG. 3, extend through openings (not shown) in arms 20 and 22 and engage tapped bores (not shown) formed in the rear portions of posts 80. Due to the above described structure, that portion of the invention inside housing B may be removed therefrom when the front piece D is separated from the housing. Conductors 28, 30 and 32 are fabricated with substantial slack therein to permit that portion of the invention in the housing to be removed therefrom through the open end 12.

The use and operation of the differential fluid pressure actuated electrical switch has been previously described in detail and need not be repeated. When the hollow bodies 62 are relatively small, it has been found desirable to form them of electroless nickel. In the larger sizes, the hollow bodies 62 are relatively small, it has been found desirable to form them of electroless nickel. In the larger sizes, the hollow bodies 62 are preferably formed from stainless steel sections, welded together. The wall thickness of the bodies 62 may be relatively thin, and will withstand high fluid pressures without damage. From experience it has been found that when the wall thickness of one of the bodies 62 is but 0.020 inches, the interior ,of the body may be subjected to a fluid pressure of 6,500 pounds per square inch without any detrimental effects. Due to the configuration of the bodies 62, the wall sections thereof are under tension only, when subjected to fluid pressure. Each body 62 as shown in FIG. 4 has a diameter that is twice the maximum thickness of the body. Due to this configuration deformation of each body 62 is linear relative to the pressure applied to the interior thereof.

A second form E of fluid pressure actuated switch is shown in FIG. 6 that includes a housing 82 having an open end 84 that removably receives a plug 86. Plug 86 supports an electric switch 88 which extends into housing 82. Switch 88 is placed in either an open or closed condition by a spring-loaded actuating member 90 disposed in housing 82 that normally occupies the first position shown in FIG. 6. A connector 92 of conventional design projects outwardly from plug 86, and is electrically connected to the switch by means not shown.

Housing 82 includes a continuous side wall 94 and end wall 96. The end wall 96 supports a tubular fitting 95 that is in communication with a hollow toroidal resilient body 62 of the same structure as the body 62 shown in FIG. 4. Body 62 (FIG. 6) is situated inside housing 82, rearwardly from end wall 96. Those portions of the resilient body 62' common to body 62 are identified in FIG. 6 by the same numerals used in FIG. 4, but to which a prime has been added. Force-imparting member 68' extends rearwardly through an opening 98 in a transverse partition 100 in housing 82, with the rear end of member 68' being in abutting contact with actuating member 90 when the actuating member is in a first position.

As the pressure on fluid in body 60' increases, the body deforms longitudinally and moves the actuating member 90 rearwardly from the first position shown in FIG. 6. After the actuating member 90 is moved rearwardly a predetermined distance to a second position, the switch'88 is placed in either an open or closed position. A stop 102 is mounted on forceimparting member 68', as may best be seen in FIG. 6, in such a position that it contacts partition 100 immediately after the actuating member is in the second position. The stop 102 cooperates with partition to limit the rearward longitudinal deformation of body 62, and prevents exertion of an excessive force against the switch 88 as a result of high fluid pressure in body 62'. When the fluid pressure in body 62' is released or lowered, the resiliency of the body returns the force-imparting member 68' to the position shown in FIG. 6,

whereby the actuating member 90 returns to the first position.


1. In a differential fluid pressure actuated, temperature stable, electrical switch assembly:

a. a housing that includes first and second ends and a connecting sidewall, said second end having first and second spaced fluid passages extending therethrough;

b. first and second rigid tubes inside said housing supported from said second end and in communication with said first and second passages, said tubes extending towards said first end;

c. first and second longitudinally deformable hollow resilient toroidal bodies in said housing, which bodies define first and second confined spaces, with each of said bodies having a diameter substantially twice the width thereof, and each of said bodies including flat, parallel first and second spaced center portions, with said first center portions secured to the ends of said tubes most adjacent said first end, and the interior of said bodies in communication with the interior of said tubes;

(1. first and second force-imparting members that extend towards said first end and are secured to said second center portions of said first and second bodies;

e. an elongate actuator inside said housing that includes first and second force-receiving portions that are axially aligned with said first and second force-imparting members;

f. a frame supported in a fixed position inside said housing adjacent said first end thereof;

g. a stiff but somewhat resilient, thin, elongate member that extends towards said second end from said frame and on the end most adjacent said second end is secured to the center of said actuator to hold said actuator in a first position, said member of such length that when said actuator is in said first position said first and second force-imparting and first and second force-receiving portions are in abutting contact when the interiors of said first and second bodies are at ambient pressure, said member preventing the center of said actuator moving longitudinally relative to said housing, but said member allowing said actuator to pivot relative to said housing; an electrical connector mounted on said first end and extending therethrough;

i. an electric switch assembly mounted on said frame, which assembly includes a plurality of wires that extend to said connector, and said assembly including a spring-loaded actuating member which when in a second position maintains said switch in either an open or closed condition, with said actuating member so disposed that it can be moved from said second to a third position to reverse the condition of said switch when contacted by said actuator when said actuator pivots from said first to a fourth position; and

j. stop means supported from said frame for limiting the pivotal movement of said actuator from said first position to fourth and fifth positions, with said first body when fluid therein is at a pressure greater than that of fluid in said second body deforming towards said first end a greater distance than said first body to cause said first force-imparting member to pivot said actuator into said fifth position where said actuating member is not moved, and with said second body when said fluid therein is at a pressure greater than that of said fluid in said first body deforming towards said first end a greater distance than said first body and pivoting said actuator into said fourthposition, which actuator when in said fourth position moves said actuating member to said third position, with said first and second bodies when the pressure on the fluid therein is equal imparting equal forces on said actual l i I

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3922515 *Apr 23, 1973Nov 25, 1975Meisenheimer Jr Daniel TTemperature compensated pressure differential sensing device with switch actuated by pressure capsule
US4446344 *Oct 26, 1981May 1, 1984International Freezer Corp.Pressure operated switch including an expandable flat tube
U.S. Classification200/83.00D, 92/34, 200/83.00B, 92/43
International ClassificationH01H35/32, H01H35/24
Cooperative ClassificationH01H35/32
European ClassificationH01H35/32
Legal Events
Jan 3, 1989ASAssignment
Effective date: 19881129