US1921795A - Switch - Google Patents

Description

G, O. WILMS Aug. 8, 1933.

SWITCH ddluag Aug 8, 1933- G. o. wlLMs 1,921,795

SWITCH Fjrled Nov. l2, 1931 2 Sheets-Sheet 2 lll/0 @um Ff 0 5g V/ Z Jim1.

' @www UNITED STATES PATENT OFFICE SWITCH Gustav O. Wilms, Milwaukee, Wis., assignor to Allen-Bradley Company, Milwaukee, Wis., a. Corporation of Wisconsin Application November 12, 1931 Serial No. 574,517

6 Claims. (Cl. 200-83) This invention relates to electric switches and Referring now more particularly to the accomrefers more particularly to the actuating mechapanying drawings, the numeral represents a nism of switches controlled from relatively slow cylindrical housing which, as will be later demoving elements such as pressure switches, float scribed, forms the support of the entire mecha- 5 switches, and the like. nism. This cylindrical housing has a flange 6 60 It is an object of this invention to provide at one end and is internally threaded as at 7 at novel mechanism for translating a relatively slow its other end. motion into a quick positive snap action suitable Closing the end of the cylindrical housing for opening and closing electric switches and for adjacent the ange 6 is a diaphragm 8 of rubber actuating similar appliances. or other suitably flexible material. The peripheral Another object of this invention is to simplify edge portion of the diaphragm 8 overlies the ange the design and construction of devices of this 6 and is securely clamped between' the llange 6 nature so as to facilitate manufacture and reand a diaphragm cover 9. The cover 9 is in the duce the 'cost thereof. form of a shallow cup whose diameter is substan- Another object of this invention is to provide tially equal to that of the cylindrical housing and 70 a compact unitary construction in which the enhas an annular flange 10 similar to the flange 6. tire mechanism is mounted from a single com- A plurality of circumferentially arranged bolts paratively small tubular supporting member, so 11 passing through aligned openings in the anges as to effect a substantial reduction in overall size 6 and 10 and the diaphragm, serve to connect the and greatly increase its applicability to varying flanges and clamp the diaphragm peripheral edge 75 installation requirements. portion therebetween.

And a further object of this invention is to The diaphragm cover, with the diaphragm thus employ a spring enclosure for the supporting forms a chamber which may be communicated base` of the entire mechanism. with a source of pressure, noi'l shown, through With the above and other objects in view which a pipe line 12 or other means of communication 30 will appear as the description proceeds, this inthreaded in a nipple 13 fixed to the diaphragm vention resides in the novel construction, comcover. The relatively slow movement of the diabination and arrangement of -parts substantially phragm 8 effected by pressure changes within as hereinafter described and more particularly this chamber, is translated into a quick positive denedby the appended claims, it being undersnap action to open and close the switch indi- 35 stood that such changes in the precise embodicated generally by the numeral 14, in a manner ment of the herein-disclosed invention may be now about to be described. made as come within the scope of the claims. Slightly inwardly of the lianged end of the In the accompanying drawings, one complete cylindrical casing 5 is a fixed guide plate 15. The

A example of the physical embodiment of this inplate extends across the cylindrical housing and 90 vention is illustrated constructed according to has a central opening 16 surrounded by four equithe best mode so far devised for the practical spaced openings 17 near its outer edge. Posiapplication of the principles thereof, and in tioned between the guide plate 15 and the dia- Which: phragm is a plate 18 which lies flat against the Figure 1 is a Vcross section taken through a diaphragm. This plate 18 has a central stud 19 95 pressure switch embodying this invention; xed thereto to project through the opening 16 Figure 2 is a front plan view of the switch with in the guide plate and four longer studs 20 fixed the COVGI 0f its enclosing Casing brOken away to its outer edge portion to project through the and the spring and its associated retaining stops openings 17. removed; The outer extremities of the studs 20 are re- 100 Figure 3 is a side view of the structure with duced in diameter to provide projections 21 which portions broken away and in section and illusare detachably engaged in openings 22 formed trating the parts in the positions they occupy in a spring seat 23. The spring seat 23 has a with the switch open; central pin 24 fixed thereto in axial alignment Figure 41s a perspective view of the diaphragm with the axis of the cylindrical housing and the 105 follower, the spring and associated elements, seppin 19, and is directed toward the pin 19. arated, but arranged in their proper order of as- With the spring seat 23 properly engaged with sembly; and the studs 20, the adjacent ends of the pins 19 Figure 5 is a fragmentary bottom view taken and 24 are spaced apart a distance slightly greater 5 on the plane of the line 5 5 of Figure 2. than the thickness of a tripping lever 25, to be 110 later described, and disposed between the ends of the pins.

Engaging the plate like spring seat 23 is a compression spring 26 whose opposite end abuts a plate 2'7'provided with a central pin 28 which engages a 'cup-shaped nut member 29 having a threaded connection with the internal threads 7 in the adjacent outer end of the cylindrical housing. The securement of the cup-shaped nut 29 to the housing places the spring in compression to a degree depending upon the distance the cupshaped nut is threaded into the housing; and as the force of the spring is applied directly to the diaphragm through the four studs 20, the adjustment of the nut 29 controls the pressure at which the mechanism operates. A disc-like diaphragm follower 30 having legs 31 projected from its peripheral edge to engage the bottom of the shallow cup-shaped diaphragm cover, provides a support for the diaphragm when the pressure within the chamber dened by the cover 9, is less than that of the spring.

The normal position of the parts, that is, with no pressure, or a pressure less than that of the spring on the diaphragm exterior, as illustrated -in Figure 1, holds the tripping lever 25 in its position closing the switch 14.

The tripping lever 25 is formed from at bendable metal and is pivotally mounted at its inner end by a cross pin 33 having its outer ends received in suitable openings in the wall of the cylindrical housing at a point above its longitudinal axis. YThe longitudinal axis of the lever intersects the axis of the cylindrical housing so that the lever passes between the adjacent ends of the pins 19 and 24, as hereinbefore brought out. The free end of the lever extends outwardly of the cylindrical housing through an opening 32 in the lower portion of its wall, and is bent to form an offset substantially Ushaped end portion 34.

The oiset at the free end of the tripping lever is such that when the parts are in their positions illustrated in Figure 1, the offset end portion just engages the flange 6 and provides a stop to limit the movement of the lever in one direction.

Mounted from the end portion k34 of the lever is a spring tripping nger 35. This finger 35 is substantially U shaped in cross section and has the inner ends of the side flanges disposed between, and pivotally connected as at 36 with, ears 37 directed outwardly from the offset end of the lever. At the outer end of the tripping .linger is a roller 38 and an expansive spring 39 is conned between the nger and the outermost end of the lever offset portion so that the outer free end of the nger is yieldingly urged upwardly toward the cylindrical housing 5, to engage the roller 38 with a V shaped cam portion 40 on a yoke-like contactor carrier 41.

The carrier 41 is preferably formed of two separate members each bent to form one-half of a yoke and having their adjacent ends directed downwardly and riveted together as at 42. The side edges of these ends are cut so as to provide the V shaped cam portion 40 with which the roller 38 engages. The side arms 43 of the yoke extend upwardly to embrace the cylindrical housing 5 and are pivotally connected therewith as at 44. The side arms` also extend upwardly beyond their pivotal connection with the cylindrical housing which is on a horizontal axis intersecting the axis of the cylinder, to have their extreme outer ends connected by an insulating panel 45 which is fixed thereto by screws 46 threaded in tapped openingsformed in flanges 47 at the ends of the yoke arms. This insulating panel 45 carries the movable contactors 48 of the switch 14 so that upon movement of the yoke-like carrier 41 the switch is opened and closed.

Movement is imparted to the yoke-like carrier 41 whenever the motion of the tripping lever carries the roller 38 past the apex of the V shaped cam end 40, and as long as the roller 38 is at either side of the apex, the spring 39 holds the carrier 41 at one or the other of its limits of movement. The limits of movement of the carrier 41 are defined by the engagement of the sides of notches 49 in the side arms 43, with stops 50. It is observed that the stops 50 are the ends of pin 33 which mounts the lever 25..

In theposition illustrated in Figure 1, the roller 38 engages that side of the V shaped cam end 40 which holds the carrier 41 at its limit of movement maintaining the switch closed, and in the position illustrated in Figure 3, the carrier is held at its opposite limit of movement holding the switch open.

It is obvious that as pressure builds up within the diaphragm cover and the diaphragm moves against the action of the spring 26, the tripping lever 25 will be carried along forcing the roller 38 outwardly toward the apex of the V shaped cam end 40. During this action the compression of the spring 39 increases so that the instant the roller crosses the apex of the V shaped end 40, the stored up energy in the spring 39 snaps the contactor carrier to its opposite position opening the switch. The same snap action, but in the opposite direction, is obtained during the return movement of the tripping lever with lessening of the pressure on the diaphragm.

To preclude the possibility of chattering and poor contact pressure which might result from the roller 38 being held on the exact apex of the cam end 40, play is provided between the lever 25 115 and its actuating means, which as hereinbefore noted, is alTorded by having the distance between the tips of the pins 19 and 24 greater than the thickness of the lever. Hence it is practically impossible for the roller to stand on exact dead center. This condition is even further precluded, when the switch is closed, by providing contact pressure springs 51 for the contactors which are placed in compression by the closing of the switch and tend to move the carrier 41 to its 125 switch opening position.

The switch 14 obviously may be of any suitable design and comprise any number of pairs of contacts to suit various requirements, and in the present instance is a double pole, single throw switch. The movable contactors 48 comprise metal cross pieces 52 to which the contactors per se are secured, and the cross pieces are connected with the panel 45 by stems 53 ixed to the panel and slidably but non-rotatably received in openings in the cross pieces 52. The contact pressure springs 51 are coiled about the stems 53 and yieldably urge the cross pieces outwardly from the panel, movement of the cross pieces by the springs being limited by suitable stop abutments on the ends of the stems.

The stationary contacts 54 are carried by terminal members 55 xed to a terminal head 56 supported from the cylindrical enclosing housing, preferably by having certain of the bolts 11 passed 145 through it and holding it to the ange 6. 1 Ihe terminal members 55 provide means for the attachment of conductors 57, and it is noted that the terminal members are formed so as to locate the stationary contacts above the cylindrical housing between its ends, thus locating the switch within the length of the cylindrical housing.

It is observed that the contactor carrier 41 carries a pin 58 projecting from one of its side arms. This pin provides means for actuating a relief valve 59, which may be used when the switch controls compressors, to relieve the pressure in the outlet line from the compressor after the desired pressure in the tank is reached and the compressor stopped, the `purpose being to reduce the load on the compressor motor when it cuts in.

As best shown in Figure 5, the relief valve has an inlet port 60 and an outlet port 61 communicated through a passage 62 which is normally closed between the ports by a ball 63. When the switch is opened the contactor carrier, through the pin 58 engaging a push pin 64, holds the ball from its seat. y

The relief valve is conveniently mounted from the cylindrical housing by having an attaching web 65 overlying the flange 6 and having the adjacent screw 11 passed through the web.

The entire mechanism may be suitably enclosed by a casing 66 and is conveniently secured therein by having two of the bolts 1l extended and passed through openings in the back wall 67 of the casing. Nuts secured to these extended bolts draw the entire mechanism against the wall 67 with the diaphragm cover engaging its inner surface and the nipple 13 extending through on opening 68 formed in the rear wall 67. The open front of the casing is closed by a cover 69 shaped to conform to the mechanism and secured to the casing in the conventional manner.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art towhich an invention of this character appertains, that this invention provides an exceptionally compact mechanism for translating a relatively slow motion into a snap action, and that this compactness of structure results primarily from the fact that the tubular housing which forms the enclosure for the spring, serves as a support for the entire mechanism. The unitary construction thus afforded greatly facilitates the application of the device to various installations and particularly facilitates its disposition within an enclosing casing.

What I claim as my invention is:

1. A switch of the character described comprising a i-lxed cylinder, a ange on the cylinder, a diaphragm having its peripheral edge portion engaging the ange and movable into the cylinder upon the application of pressure on its exterior, a terminal head having a portion engaging the iiange,l means for securing the diaphragm to the ange, part of said means securing the terminal head to the ange, a stationary contact carried by the terminal head, a movable contactor engageable with the stationary contact, a contactor carrier pivotally mounted from the cylinder and adapted to carry the contactor from one `position tothe other, a spring within the cylinder opposing inward movement of the diaphragm, and means responsive to motion of the diaphragm and spring for imparting a snap action to the contactor carrier upon predetermined movement of said means.

2. In a' pressure switch of the character described having switch instrumentalities operable in accordance with the motion of a diaphragm in response to pressure changes and wherein the Aswitch instrumentalities remain at rest throughout a denite range of pressurechange, means to transmit movement of the diaphragm 3 to the switch instrumentalities comprising, spaced walls, one' of which bears directly against one face of the diaphragm, spacing means carried by one wall and bearing against the other wall to maintain said walls in parallel spaced relation at all times, an expansive spring engaging the wall spaced from the diaphragm to oppose movement of the diaphragm in response to increasmg pressure, a lever pivoted between the `spaced walls and intersecting the axis of said spaced walls and spring, abutments carried by the spaced walls and engageable with opposite sides of said pivoted lever on said intersected axis, the ends of said abutments being spaced apart and the space between said ends being a factor in the determination of the period of rest of the switch instrumentalities, and means to impart movement of the outer free end of the lever to =the switch instrumentalities.

3. In a pressure switch of the character described having switch instrumentalities operable in accordance with the motion of a diaphragm in response to pressure changes and wherein the switch instrumentalities remain at rest throughout a definite range of pressure change, means to transmit movement of the diaphragm to the switch instrumentalities comprising, a pair of spaced walls, one of which bears directly against the face of the diaphragm, a plurality of spacing posts carried by one wall and projected toward the other wall to have a readily detachable connection therewith so that said spaced walls are rigidly connected in parallel spaced relation, a compression spring bearing against the wall spaced from the diaphragm to oppose movement of the diaphragm in response to increasing pressure, a lever pivoted between the spaced walls to intersect the axis of the spaced walls and the spring, a lever engaging pin carried by each of said spaced walls, said pins being axially aligned and disposed on said intersected axis of the walls and spring and having their ends spaced apart a predetermined distance, said distance being a factor in the determination of the period of rest of the switch instrumentalities, and means to impart movement of the outer free end of the lever to the switch instrumentalities.

d. In a pressure switch of the character described having switch instrumentalities operable in accordance with the motion of a diaphragm in response to pressure changes and wherein the switch instrumentalities remain at rest throughout a deinite range of pressure change, the comend by the diaphragm, an adjustable spring stop closing the other end of the cylinder, said spring stop being readily removable to permit access to the interior of the cylinder, a floating carriage within the cylinder and comprising a pair of spaced discs one of which bears against the dia` phragm, means carried by one of the discs and readily detachably engaged with `the other to maintain the same in a fixed parallel relation, a compression spring coniined between said oating carriage and the adjustable spring stop, a lever pivoted Within said cylinder between the spaced discs with a portionntersecting the axis of the cylinder and projecting outwardly of the cylinder, opposed abutments axially carried by the spaced discs to engage the lever portion intersecting said cylinder axis and impart movement to said lever, and means associated with the lever portion externally of the cylinder to operate the switch instrumentalities from the movement o1 the lever, said opposed abutments being spaced apart a predetermined distance, which distance is a factor in the determination of the duration of said period of rest of the switch instrumentalities andleing adjustable by the substitution for the disc engaged by the spring of another disc having a lever engaging abutment with different height.

5. In a pressure switch of the character described having switch instrumentalities operable in accordance with the motion of a diaphragm in response to pressure changes, the combination of a cylinder closed at one end by the diaphragm, a

floating carriage in said cylinder comprising a diaphragm engaging disc in flat engagement with the diaphragm, a spring engaging disc and a plurality of spacing posts 'carried by one of said discs and having a readily detachable connection with the other disc to rigidly hold the discs in parallel spaced relation, a compression spring within the cylinder having one end bearing against said spring engaging disc, a cover having a threaded adjustable connection with the open end of the cylinder whereby removal of the cover` enables quick withdrawal of the spring and the spring engaging disc of the floating carriage, a lever pivoted within the cylinder between said discs with its outer free end extending externally of thevcylinder, lever engaging pins carried by the discs with their axes coinciding substantially with the axis of the cylinder and their opposed ends disposed at opposite sides of the lever to be engageable therewith, and means associated with the outer free end of the lever to operate the switch instrumentalities upon movement of the n lever in response to motion of the diaphragm.

6. In a pressure switch having switch instrumentalities operable in accordance with the motion of a diaphragm and a spring in response to pressure changes and wherein a pivoted lever imparts said motion of the diaphragm and the spring to the switch instrumentalities and the switch instrumentalities remain at rest throughout a definite range of pressure change, a floating carriage disposed between the diaphragm and

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