US2345757A

US2345757A - Explosion-proof switch housing

Info

Publication number: US2345757A
Application number: US317022A
Authority: US
Inventors: Ray F Lester
Original assignee: Crouse Hinds Co
Current assignee: Crouse Hinds Co
Priority date: 1940-02-02
Filing date: 1940-02-02
Publication date: 1944-04-04
Anticipated expiration: 1961-04-04

Description

April 4, 1944. R LESTER 2,345,757

EXPLOSION PROOF SWITCH HOUSING Filed Feb. 2, 1940 5 Sheets-Sheet l BY iff/Zw MW ATTORNEYS.

April 4, 1944. R F LESTER 2,345,757

EXPLOSION PROOF SWITCH HOUSING Filek-Feb. 2, 1940 3 Sheets-Sheet 2 j? l NVENTOR. @-4- Qjm l f ATTORNEYS.

April 4, 1944.

R. F. LESTER 2,345,757

EXPLOSION PROOF SWITCH HOUSING O HO 55 Ki? ATTORNYS Patented Apr. 4, 1944 PATENT OFFICE EXPLOSION ZIROOI" SWITCH HOUSING Bay F.'Lester, Syracuse, N. Y.. Hinds Company, Syracuse,

vtion of New York assigner to Crouse. N. Y., a corpora- Appucauon February z, loro, semi No. 311,022

2 Claims. This invention relates to switch lhousings designated as the explosion proof type employed to house switches and other electrical apparatus in hazardous locations.

The embodiment of the invention here shown is intended particularly for use in hospital operating rooms where there is likely to be present ether, or other inammable vapors. The structureherein referred to is intended to be mounted in the wall of the'operating room near `or adiacent the floor, and involves a particularly durable structure permitting the switch to be operated by the foot to avoid the necessity of the surgeons, and operating room attendants, operating the switch manually by hand. It Vis desirable in mounting switches in such locations that the exposed surface of the switch be of attractive iinish and be properly mounted so that the cover member of the switch is properly tted against the wall of the room.

'I'he invention has as an object a switch housing of the type refened to embodying a structure by which the body of the housing may be installed in the wall structure and connected in the conduit system during the construction of the building, a cover member in which the switch actuating mechanism is mounted, and an intermediate member carried by the body and in which the switch is mounted, the intermediate member being adjustable toward and from the surface of the wall so that the cover member is properly mounted on the finished wall surface of the room in a neat and attractive manner.

The invention has ,as a further object a switch housing of the type referred to embodying a structure effecting an efllcient flame-tight joint between the cover member and the intermediate member. l

A further object of the invention-is a switch housing embodying a structure whereby the elements -subsequently installed on the body of the fitting and which enclose the switch may be properly sealed as a flame-tight unit-,at the factory with the leads from the switch, or other apparatus, mounted in the housing extending from said unit for connection within the body member to the conductors in the conduit system, and the unit quickly and conveniently installed in the body, ,whereby the complete housing forms a tight explosion proof enclosure for the apparatus mounted therein.

The invention consists in the novel features and in the combinations and constructions herein after set forth and claimed.

In ldescribing this invention, reference is had (Cl. 20o-168) to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure 1v is a top plan view of a switch housing 5 embodying my invention.

Figure 2 is a sectional view taken on line 2 2, Figure 1.

Figure 3 is a top plan view of a switch housing generally similar to that shown in Figures 1 and 2 embodying the modified mounting for the switch and a thermostatic actuating mechanism.

Figure 4 is a. view taken on line 4-4, Figure 3. Figure 5 is a top plan view of a modified form the switch housing shown in Figures 1 and 2. Figure 6 is a sectional view taken on line 6 6, Figure 5.

The invention consists oi.'v a body member in the nature of a conduit outlet box which may be installed in the wall structure and connected in the conduit system. A sleeve is threaded into the outlet boilr and a cover member secured to the outer end of the sleeve. The sleeve is threaded into the box to provide adjustment of the cover member to properly position the same against the wall surface. The switch is mounted within the sleeve member and is actuated to on and od position by switch operating mechanism mounted in the cover member. The construction is such that the body, sleeve, and cover member, form an explosion proof housing for the switch. If it is desired to have the switch housing effectively sealed from the conduit system, the invention further contemplates a cup shaped member arranged in the sleeve embodying a structure whereby the wires connected to the switch are sealed in the bottom of the cup-shaped member and the cover forming a. dame-tight or explosion prooi closure for the open end of the cup shaped member.

The body I may be of any desired form, it being here shown as of circular formation and provided with a pluralityof radially extending hub members II provided with an internally threaded passage I2 to receive the ends of the conduits. The body I0 is provided at one side 45, with an internally threaded opening into which an internally threaded sleeve I3 is threaded. The sleeve I3 is formed at its outer edge with a radial flange I4 formed with a plurality of concentric annular shoulders I arranged in step formation.

In Figures 1 to 4, a cup shaped member I 6 is mounted within the sleeve I3 and is likewise formed with a radial flange I1 formed with an intermediate portion I8 extending in angular relationship to the axis of the cup shaped mem- 65 ber. Both the inner and outer sides of the intermediate portion 'I8 is formed with'a plurality of concentrically arranged annular shoulders, i

extending through thebottom of the member I6 may be connected to the conductors of the conduit systemand the unit comprising the cup shaped member with the cover20 attached thereto inserted in or mounted upon the sleeve I3. as by screws 41.

'l This procedure avoids the necessity of the 'workman disrupting the joint between the cup intermediate portion I8 of flange Il is formed with a step formation 24 complemental to the step formation on the outer surface of the intermediate portion I8. The arrangement is such that the step formation 24 of the cover member is also complemental to the step formation I on sleeve I3. Where it is not necessary to seal off the interior of the switch housing from the conduit system, the cover may be mounted directly on the sleeve I3, as illustrated in Figure 6.

In Figures 1 and 2, the switch 25 is carried by a supporting plate 26 mounted on inwardly extending projections 21 formed on the cup shaped member I6. The switch actuating mechanism is carried by the cover member 20, the cover being formed with a boss 28 extending outwardly and at an angle to the axis of the housing and being formed with an aperture 29, the inner lportion of which is threaded to receive a bushing 30. An operating stem 3| is slidably mounted-in the bushing 30 and a button 32 is secured to the outer end of the stem 3| land is slidably mounted in the recess 29. The stem 3| and button 32 are urged outwardly by a helical compression spring 33 encircling the stem and the outer end of the bushing 30. In Figures 5 and 6, the cover 2|) is provided with a pair of operating buttons 32, and a pair of switches are mounted within'y the sleeve I3 on inwardly extending bosses 34.

In Figures 3 and 4, the cover 20 is of substantially fiat circular formation and is formed with a threaded aperture to receive a which is rotatably mounted a stem 36. A mercury tube switch 31. is secured tothe lowerV end of the stem 36, and the stem is oscillated in the bushing 35 by a thermostat mechanism indicated at 38 enclosed in a housing 39 mountedupon the cover. 4

The bottom wall of the cup shaped member I8 is formed with one or more apertures .to permit the passage of conductors 40 from the interior of the body I0 to the interior of the cup shaped member IB. These apertures are formed in a transversely extending thickened portion 4| formed with internal anges 42 at the top and bottom of each passage. After the conductors 4|) have been extended through the passages, the passages are filled with a sealing medium 43 and the flanges 42 assist in holding the sealing mey dium in the passages. l Preferably, the leads 40 are extended through the passages in the bottom of the cup shaped member and the leads sealed in said passages, the

switch

25, 31 installed, and the cover 20 secured to the flange I1, as by screws 46, all at the factory. To install the switch, itis only necessary for the workman to screw the sleeve I3 into the body I0 the proper distance to bring the flange 22 of the cover in close proximity to the nished wall surface 23. Thereafter, the ends of the leads 40 busting ss in shaped member and the cover and disturbing the factory seal aboutthe leads 43. The sleeve I3 provides a convenient means for adjusting the cover 20 to eifectproper mounting of the same relative toV the'finished wall surface without in lany way twisting or otherwise damaging the wiring connected to the switch. The angularly arranged stem 3| with push button 32 forms a convenient and durable mechanism permitting the switch to be operated by pressing the button 32 with the foot.

What I claim is:

1. An explosion proof switch housing comprising a body for installation within the wall structure of a room and being formed with a conduit receiving aperture and with anl opening in one side, a flame tight switch enclosure comprising a cup shaped member and a cover detachably secured in flame tight relation to the open end of said member and having a radially extending flange adapted to overlie the marginal portion about an opening in the wall structure, a switch mounted in said enclosure, lead vconductors extending from the terminals of the switch through the wall of the enclosure into said body, switch operating mechanism carried by the cover and being operable externally thereof to move the switch into on and oiI positions, said conductors and the switch operating mechanism being sealed in flame tight relation in said enclosure, means for supporting said' enclosure in the opening of the body in flame tight relation thereto, and said means being operable to adjust said enclosure toward and from the body to position the flange of the cover in contact with the wall surface.

2. An explosion proof switch housing comprising a body formed with a conduit receiving aperture and with an opening in one side, a sleeve threaded'into said opening and being formed at its outer end with an annular flange, a flame tight switch enclosure comprising a cup shaped member arranged in said sleeve and having a radially exvtenciing ,ange overlapping the ange on said sleeve, the confronting surfaces of the anges of said cup shaped member and sleeve being formed with a plurality of complemental annular shoulders arranged instep formation, a switch mounted in said enclosure, lead conductors extending through the wall of the enclosure into said body, a cover detachably secured to the open end of said cup shaped member in flame tight relation thereto, switch operating mechanism carried by the cover and being operable externally thereof to move the switch into on and olf positions, said conductors and switch operating mechanism being sealed in ame tight relation in said enclosure, said sleeve being of appreciable length and operable to adjust the enclosure toward and from the body, and means operable to detachably clamp the anges of said sleeve and cup shaped member together.

- RAY F. LESTER.

CERTIFICATE 0F CORRECTION. Patent No. 2,5LI5,757. April LI, 19th.

RAY F. LESTER.

It is hereby certified that error a ofthe above numbered patent requiring ond column, line 11.6, for

ppear-s in the printed specification correction as follows: Page l, y:esec- "nternally" read -exteznallyvg and that the said Letters Patent should be read with this correction therein that the same may confom to the record of the case in the Patent Office.

signed and sealed this 50th day of May,'A. D. 19ML.

Leslie Frazer (Seal) Acting Commissioner of Patents.

CERTIFICATE oF CORRECTION. Patent No. 2,515,757. April u, 19ML.

RAY F. LESTER.

It is hereby Certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page l, ysecond column, line 146, for internally read "externally-j; and that the said Letters Patent 'should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed this 50th day of May,'A. D. 19th.

Leslie Frazer (Seal) Acting Commissioner of Patents.