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Publication numberUS2680168 A
Publication typeGrant
Publication dateJun 1, 1954
Filing dateJul 7, 1952
Priority dateJul 7, 1952
Publication numberUS 2680168 A, US 2680168A, US-A-2680168, US2680168 A, US2680168A
InventorsMurphy Frank W
Original AssigneeMurphy Frank W
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Safety switch
US 2680168 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

F. W. MURPHY SAFETY SWITCH June 1, 1954 Filed July 7, 1952 INVENTOR Franic WMur vhy BY MQLM l I I ATTOR NE Y5 Patented June 1, 1954 UNITED STATES SAFETY SWITCH Frank W. Murphy, Tulsa, Okla. Application July 7, 1952, Serial No. 297,474

1 Claim. 1

This invention relates to a safety switch for use in controlling the operator for a pump.

In a well pump, such as a pump for irrigation systems or the like, where a substantial drop ocours in the water supply which results in the pump running without drawing any water, considerable damage may result in the pumping apparatus before the pump is shut down. It is, therefore, an object of this invention to provide an electrical switch connected to the pump operator which under normal pumping conditions will be in circuit closing condition. The switch embodied in this invention is such that if the volume of water being pumped should drop below a safe margin, the operator will be stopped this invention is to provide a safety switch structure which can be initially set so as to start the pump operator in operation, and after the pump has been in normal operation the manual setting will be released so that continued operation of the pump will be under automatic safety conditions.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claim.

In the drawings:

Figure 1 is a detailed side elevation of a safety switch constructed according to an embodiment of this invention mounted on a water pipe or duct for controlling the pump operator connected with the duct.

Figure 2 is a vertical section of the switch or regulator for the operator.

Referring to the drawings, the numeral I designates generally a pipe or duct which is connected between a pump and a well or water supply wherein the pump is operated by means of an operator II which may be an electric motor, or other operator.

In order to provide a means whereby the operator II will be stopped when the water in the pipe or duct I0 drops either below a predetermined level or becomes dry, I have provided a spring-pressed switch I2 which is interposed in the conductors I3 and I4 connected with the operator I I.

The switch I2 is spring-pressed to a normal circuit closing position so that the operator H may operate the pump for drawing water through the pipe or duct Ill. The switch I2 is carried by a support I5 which extends upwardly from a diaphragm housing generally designated as l6.

The diaphragm housing I6 includes upper and lower housing members I1 and I8, with a flexible diaphragm I9 secured between the housing members H and I8. The lower housing member i8 is formed with a boss 20, and the upper end of a pipe 2! is secured in the boss 20.

A scoop 22 is threaded onto the lower end of the pipe 2i and the scoop 22 is mounted in opposed relation to the direction of movement of the water in the pipe I 0 so that as the water moves to the right, as viewed in Figure 1, the water will enter the scoop 22 and rise upwardly in the pipe 2| so as to thereby place the trapped air in pipe ZI and in the space below the diaphragm it under sufficient pressure so as to flex diaphragm I9 upwardly.

A lever operating rod 23 is secured at its lower end to the diaphragm I 9 and slidably engages through the upper housing member operating lever 24 is rockably mounted on a pivot 25 and is formed with an opening 26, through which the rod or bolt 23 loosely engages.

A pair of nuts 21 and 28 are threaded onto the bolt or rod 23 on the lower and upper sides of the lever 24 so that the lever 24 may be regulated as to its movement according to the movement of diaphragm I9 and bolt 23. Switch I2 includes a downwardly projecting switch button 29 disposed in the path of the rocking movement of the short lever arm 30 of lever 24.

A spring IN is interposed between the lever arm 3t and the upper housing member I! so as to constantly urge arm 30 upwardly to circuit breaking position, with arm 30 pushing button 29 upwardly. The outer end of lever 24 is formed with a keeper notch 32, within which a manually adjustable latch member 33 is adapted to initial- ].y engage.

The latch member 33 is mounted on a pivot 34 extending between a pair of upstanding ears 35 carried by the upper housing member I1, and a spring 35 constantly urges the latch member 33 outwardly to released position. A latch operating pin 37, which is spring-pressed outwardly by means of a spring 38, is carried by a hood or cover 39 and is adapted to be manually pushed inwardly for rocking latch member 33 inwardly to engagement with the keeper 32.

When latch member 33 is engaged with keeper 32, lever 24 will be rocked upwardly on its long end and short lever arm 30 will be rocked downwardly so that the switch button 29 may move downwardly to circuit closing position. At this time, pump operator Il may be operated in the normal manner, and after a flow of water has I1. A switch been established in pipe 10 so that pressure in pipe 2| will flex diaphragm l9 upwardly, lever 24 will be raised upwardly by flexing of diaphragm l9 and latch member 33 will be released from keeper 32 so that continued operation of operator H-will be under safety conditions.

In the event, after initial starting of operator E l, the flow of water in pipe [0 should be stopped, diaphragm 19 will be released from air pressure on the lower side thereof and will flex downwardly and, in addition, spring 3| will swing short lever arm 30 upwardly to engage switch button 29 and move switch 12 to a circuit breaking position.

With a safety switch as hereinbefore described the switch may be mounted at any-point in the water duct, such as an irrigationcanal or the like, and if the Water should be exhausted in the canal or duct, the pump which is connected with the canal will be promptly stopped so that the pump will notbe damaged bydry operation.

I do not mean to confine myself to the exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claim.

A safety switch for a pump operator which includes a liquid duct, a vertical pipe projecting into said duct, and a scoop at the lower end of said pipe; said switch comprising a diaphragm housing at the upper end of said pipe, a flexible diaphragm in said housing, a normally closed switch carried by said housing, a spring-pressed lever rockably carried by said housing and constantly urging said switch to circuit breaking position, releasable latch means for holding said lever disengaged from said switch, and means connected with said diaphragm and engageable with said lever to effect release of said latch means by presence of a predetermined liquid level in said duct.

References Cited in the file of thi patent UNITED STATES PATENTS Number Name Date 1,45l,064= Dunajeff Apr. 10, 1923 2,119,783 Harrington June 7, 193?, 2,293,574 Teach et al. Aug. 18, 1%2 2,339,957 Smith Jan. 25, 1944 2,440,981 Smith May 4, 19-l8 2,473,726 Payne June 21, 1949

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1451064 *Jan 31, 1922Apr 10, 1923Dunajeff Leonid ASpeed indicator
US2119783 *Jan 18, 1936Jun 7, 1938Autocall CompanyFlow and pressure responsive indicator
US2293574 *Oct 23, 1940Aug 18, 1942Ingersoll Rand CoControlling device
US2339957 *Oct 26, 1942Jan 25, 1944Shell DevPipe line control system
US2440981 *Dec 29, 1944May 4, 1948Builders Iron FoundryPumping system
US2473726 *Dec 28, 1946Jun 21, 1949Harvey Payne & Co WElectric pump
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2747375 *May 14, 1953May 29, 1956Gen Motors CorpIce making apparatus
US2767277 *Dec 4, 1952Oct 16, 1956Wirth James FControl system for power operated fluid pumps
US2794088 *Jun 16, 1953May 28, 1957Ostby Burton KAutomatic switch
US2810061 *Oct 15, 1956Oct 15, 1957Serrone Peter JReleasable latching assembly for door switches
US2834845 *Mar 12, 1956May 13, 1958Nielsen Axel LSump pump control
US2844678 *Apr 20, 1953Jul 22, 1958Nielsen Axel LSump pump system
US2883485 *Feb 14, 1958Apr 21, 1959Willard David SSafety baroswitch
US2885506 *Apr 28, 1955May 5, 1959Western Electric CoFluid pressure sensitive control devices
US2920469 *Dec 6, 1956Jan 12, 1960Gen ElectricControl system for wash water storage and re-use system
US2922854 *Sep 16, 1957Jan 26, 1960Nielsen Axel LSump pump control
US2923790 *Dec 27, 1957Feb 2, 1960Ernst John JPositive action low pressure pump cutoff switch attachment
US2953659 *May 16, 1955Sep 20, 1960Phillips Petroleum CoShut-down device
US2955173 *Nov 17, 1958Oct 4, 1960Harry KranzSafety device for swimming pool pumps
US2968707 *Nov 20, 1956Jan 17, 1961Perfect Circle CorpControl means for oil well pumps
US2971070 *Aug 4, 1958Feb 7, 1961Robertshaw Fulton Controls CoRefrigerator compressor control
US3054274 *Dec 18, 1959Sep 18, 1962Borg WarnerIce maker controls
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US3278704 *Sep 14, 1964Oct 11, 1966Leo Smith HenryPressure-actuated circuit breaker
US3842224 *Jun 13, 1973Oct 15, 1974Ecodyne CorpPressure switch with diaphragm for liquid bearing solids
US4565488 *Oct 21, 1983Jan 21, 1986Accuspray, Inc.Compressor
US5140113 *May 22, 1991Aug 18, 1992United Electric Controls CompanyDifferential pressure control switch with a pivoting actuating lever and a biasing spring sealed in a housing
US5570481 *Nov 9, 1994Nov 5, 1996Vico Products Manufacturing Co., Inc.Suction-actuated control system for whirlpool bath/spa installations
US6059536 *Jan 21, 1997May 9, 2000O.I.A. LlcEmergency shutdown system for a water-circulating pump
US6342841Apr 9, 1999Jan 29, 2002O.I.A. LlcInfluent blockage detection system
US7931447Nov 17, 2006Apr 26, 2011Hayward Industries, Inc.Drain safety and pump control device
US7988425Jun 6, 2006Aug 2, 2011Stingl David APump and alarm control
US20080003114 *Nov 17, 2006Jan 3, 2008Levin Alan RDrain safety and pump control device
US20090038696 *Jun 27, 2008Feb 12, 2009Levin Alan RDrain Safety and Pump Control Device with Verification
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U.S. Classification200/83.00J, 200/83.00S, 200/81.90R, 62/177, 200/81.00R, 200/84.00R, 392/471, 417/43, 200/318
International ClassificationH01H35/34, H01H35/24, H01H35/26
Cooperative ClassificationH01H35/2607, H01H35/34
European ClassificationH01H35/34, H01H35/26B