US2374636A - Electric switch - Google Patents

Description

April 1945. E. J. DILLMAN 2,374,636

ELECTRIC SWITCH Filed 001;. 21, 1943 2 Sheets-Sheet 1 s5 32 W2 l A "n 52 37 4 l 1a FIGZ I FIGB INVENTOR.

ATTORNEY I April 24, 1945. E. J. DILLMAN ELECTRIC SWITCH Filed Oct. 21, 1945 2 Sheets-Sheet 2 FIG? FIG.6

INVENTOR.

w ATTORNEY Patented Apr. 24, 1945 ELECTRIC SWITCH Earnest J. Dillman, Detroit, Mich.,

troit Lubricator Company, corporation of Michigan masculine-, Detroit, Mich... sg Application October 21, 1943, serial No.50ih19l 6 Claims. (01. zoo-as) This invention relates to new and useful improvements in electric switches and more particularly to switch operating means.

An object of the invention is to provide novel means for adjusting the operating point of the switch.

Another object is to provide means to prevent injury to the switch operating means.

Another object is to provide a switch of simple and. compact construction which is efficient in operation.

The invention consists inthe improved construction andeombination of parts and their cooperative relation to be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings to be taken as a part of this. specification, there are fully and clearly illustrated several preferred embodiments of the invention, in which drawings- Figure 1 is an enlarged view in front elevation of a switch embodying the invention and having the cover member removed and certain partsbroken away to show the internal construction;

Fig. 2 isa full size view in section on the line 2-2 of Fig. 1;

Fig. 3 is a view of the switch in Fig. 1 in rear elevation;

Fig. 4 is a view in front elevation of another form of switch embodying the invention and having the cover member broken away to show the switch operatingparts;

Fig. 5 is a view in side elevation of the switch of Fig. 4 and showing the cover member in section;

Fig. 6 is a. rear plan view of the switch of Fig. 4, and

Fig. 7 is a detail view showing a modification with an operating range controlling spring ap-.

plied to the switches of Figs. 1 and 4.

Referring to the drawings, Figs. 1 to 3 by characters of reference, 'I designates generally a housing or casing, preferably of die cast metal, having a rear wall 2 from which extends a substantially rectangular surrounding flange 3 providing top, side and bottom walls to the'front face of which the cover member-4 is secured by screws 5,. Projecting downward from the underside of the bottom casing wall there is a tubular extension or hollow supporting member 8 which converges inwardly downward to an internally cylindrical bore which is internally screw-threaded, at I. Screw-threaded into the bore 1 and sealing the same. there is a hollow plug supporting member 0 having an internal bore or passageway 8 extending longitudinally therethrough. The bore 8 is internally screw-threaded at its lower end for connection to a pressure conveying conduit or pipe leading from a switch actuatingfluid pressure source. The plug 8 has a flange engaging a bore shoulder to stop its inward movement and is locked and he ld in position byjc iamping or staking over an edge of the extension 8 against the flange, as at iii. The upper or inner end of the bore ,9 within the housing i is closed and hermetically sealed by a resilient pressure responsive member i I, preferably a metal bellows having 4 its open end portion extending into an annular groove or channel l2 in the upper or inner end of the member 8, in which channel the bellows member end portion is hermetically sealed and secured by solder or the like. The upwardly diverging wall of the extension 6 provides a lateral clearance for the bellows member II. The upper end of the bellows member is closed by an end wall or head i3 having an aperture therethrough in which there is sealed and rigidly fixed an elongated supporting member ll which extends into the bellows member II and above the wall H. The member it has a longitudinal upward opening recess or socket it which is internally screwthreaded to receive adjustably a, switch actuating rod or thrust member it which is adjustably screw-threaded in the socket It. The member it has a plurality of transversely extending internally screw-threaded lock or set screw receiving bores i1 therethrough above the end wall It, so, that when the plug 8 is screwed tightly into position at least one of the bores i! will be accessible through the front opening of the casing I for access to a set or look screw it in the accessible'bore I1 and which locks the rod It in longitudinally adjusted position. The rod it extends upward through a guide aperture is in the horizontal flange 20 of a guide and stop member in .the form of an angle bracket having a vertical flange II. The rod it may have pin receiving bores 22 for its rotated longitudinal adjustment and has its upper or inner end terminating in a stop member 23, provided by a head or downward facing shoulder engageable with the flange 2|! to prevent downward pressure, either manual or otherwise, on the bellows member II, which would change the setting or permanently stress the bellows member H. Positioned adjacent the upper end of the rod 18 and projecting inward from the rear wall 2, ,there are horizontally spaced supporting bosses 24, to which there is clamped an electric switch unit 25 of any of the snap acting types stressed to one position and now on the market. The unit 25 has a supporting base or member 28 of electric material clamped to the bosses 24 by screws 21 which pass through and clamp the :bracket flange 2i to the bosses 24. A sheet of insulating material 28 may be clamped between the flange 2i and the bosses 24 to shield the switch unit and its terminals from the rear wall 2. Reciprccally guided through the base 28 there is a sting pin 29 positioned in alinement with the rod I6 and having, atitsupper end, a head urged against the support 26 by a switch return lea insulating switch operspring II. The switch has a snap acting contact 3| carried by a snap mechanism 32 actuated by the spring 30. The contact II cooperates with and, in the form of a switch unit shown, normally engages the fixed switch contact 33 mounted on a bracket from the base 2!. The rear housing wall 2 has an opening 84 therethrough which is closed by a terminal box and lead wire conduit 35 having terminal posts 38 extending into the housing I and connected respectively by lead wires 31, It to the fixed contact 33 and the mechanism supporting the contact ii.

The operation of the switch of Figs. 1 to 3 is as follows: The rod i6 is adjusted so that the inherent resilience of the bellows member II will determine the fiuid pressure in the member Ii at which the thrust member ll, acting through the pin 2!, will move the spring ll and mechanism 32 to snap the contact 3| away from the fixed contact 33. It will be apparent that shortening of the distance between the thrust rod .head 23 and the .bellows end wall I! will increase the" pressure required to operate the switch, since;

shortening of this distance will require a greater force to expand the bellows member ll sumcient to actuate the switch. It should also be noted that the rod II can be screwed into the recess a,s14,ese

flange 65 to limit downward manual or other downward movement of the bellows member 65 which might permanently tress or injure the same. Positioned above the rod 84 there is an electric switch unit 68 substantially the same as the unit 25 of Fig. l, and therefore the primes of the reference characters used in Fig. 1 desi nate like parts of this switch unit. The unit 88 is supported from the rear wall ti on bolts 69 extending through spaced apertures in the base member 28' and is spaced therefrom by spacer sleeves I. on the bolts 89. Nuts 1|, threaded on I! so that the rod I O is under'tension, thereby further increasing the required switch actuating pressure. when the fluid pressure admitted to the bellows member through the bore 8 reaches the operating pressure for which the resilience of the bellow member I I is set, then the head I! will have been moved upward a sufficient distance so that the thrust rod II will have picked up and moved the pin 2! to its point of switch operation. when the fluid pressure within the bellows member I l decreases so that its resilience retracts or moves downward the rod I, then, as the pin 29 following the rod ll frees the spring 30, the spring a will move the switch mechanism overcenter and the contact ll into engagement with its fixed contact 33.

Referring to the switch of Figs. 4, 5 and 6, the

numeral 50 designates a housing or casing having a rear wall Bl with top and bottom forwardly extending flanges or walls 52, 53 respectively which are joined and held in fixed relation by posts 54. The casing" is closed by a U-shaped having a flange 59 which seats on the top face of the wall 53 and against which it is tightly clamped by a nut 80 screw-threaded on the member 58 and drawn up against the under face of the bottom wall 53. Supported on and hermetically closing the inner end of jthe bore through the plugmember 59, there is a resilient pressure responsive member 8i preferably a metalbellows having its lower end portion hermetically sealed. as by solder or-the like, to the'ifiange 59. The upper or inner end of the bellow 8! is closed and sealed by an end wall or head. 62 through which there is secured and sealed a supporting member 63 similar to the member and in which there is screw-threaded for longitudinal adjustment a rod or thrust member M which extends upward through a guide aperture in the horizontal flange 85 of an angle bracket 88 which serves as a guide and stop member. The rod ll terminates in a head or flange "providing a downward facing shoulder engageable with the the bolts 08, .clamp the switch unit 88 in position and also clamp and. support the vertical flange of the bracket member 85 against the rear wall 5|. Secured on" the outer side of the rear wall ii there is a terminal block 12 of electric insulating material having binding posts I3 to which are secured the ends of the lead wires 81', 38' extending through insulating grommets 14 secured through the rear casing wall. The operation of this switch of Figs. 4, 5 and 6 is the same as that of Figs. 1, 2 and 3, and therefore a description of the operation is believed unnecessary.

Referring to Fig. 7, there is shown a modification of the invention applicable to the switches of Figs. 1 and 4. For convenience of exposition, the parts are designated with the suflix a added to the reference characters, designating like parts in Figs. 1 to 3. Screw-threaded on the rod it, above the member Il for longitudinal adjustment, there is a spring support or follower member 80. Positioned between the flange 20 and the follower member and surrounding the rod it, there is a helical coil spring 8! held under compression and acting to urge the rod is downward and to collapse or compress the bellows member II. The force exerted by the spring M will accordingly be added to the force of the bellows member H! in opposition to the fluid pressure within the bellows member ii, so that the switch can be adjusted to operate at a range above the maximum range of switch operation afforded by the inherent. resilience of the bellows member il. Further description isbelieved unnecessary, as the complete operation of thi modification will be apparent from the description of the above, together with the description of Figs. 1 to 3.

What is claimed and is desired to be secured by Letter Patent of the United States is:

1. An electric switch device comprising a housing having a front wall opening, a closure member for said opening, a unitary electric switch having an operating pin and a base rigidly fixed in said housing, an inherently resilient metal bellows in said housing and having a head facing said pin, a supporting member secured in a wall aperture of said housing and supporting said bellows and having a passageway therethrough sealed by said bellows, an adjustment member carried by said bellows head and having an internally screw-threaded bore alined with said pin, a thrust rod adjustably screw-threaded in said bore and operable to engage and move said Pin to actuate said switch, means to lock said rod in adjusted position, and an apertured guide plate'in said housing and rigid with said switch base and guidingly receiving said thrust rod, said rodbeingexposed between said plate and said bellows head through said front wall opening for adjustment, the adjustment of said thrust rod relative to said pin determining the resistance of saidbellows at which said switch will be actuated.

2. An electric switch device comprising a housing having a bottom wall with an aperture thereend wall and projecting from opposite sides thereof, a thrust rodadjustably screw-threaded in said upon predetermined fluid pressure in said bellows member.

'- Justably screw-threaded in said member.

end wall and of, a thrust flange and engageable with said bracket member horizontal flange to support said expansive movement of said bellows member. a unitary electric switch having a base rigidly clamped against the interior wall of said ho sing holding said spring under compression and cooperable' with said rod to limit collapse oi said bellows member.

6. An electric switch device comprising a housing having a bottom wall with an aperture therethrough, a plug member closing said aperture, said plug member having a passageway therethrough opening through its inner passageway, said bellows member having an end wall closing its other end, a supporting member extending through and sealed in said bellows member end wall and having a longitudinal internally screw-threaded socket, a thrust rod,adtending from said member secured in compression between said plate member and said follower member and acting to oppose expansive movement of said bellows manner J. lump.

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