US2314405A - Pneumatic switch device - Google Patents

Description

March 23, 1943. C, Q KELLEY 2,314,405

PNEUMATIC SWITCH DEVICE Filed oct. 21, 1941 2 sheets-sheet 1 3 w WM f T 9 n J .w m [u 1006.0 V5 0,0% mm .A /f H u u Q 0% f 7 my 4 4 M w 1 0 3 a in 721K.. KIM/f a H v l |n u 2M /m wWI/W WEEE m ll .,I mtm l fl/V //A/// v J r am f/ J 8 fw [v /,2 l, 1H l1 .I 8 n I Ill I Il l 0 MU. Imw w m w, M f v/ ow R v0 x 5 w 5 wf 1 .1W 5 o 9 a., q w www.. W a@ @f 7 Nw 0 wwwmm V /r Patented Mar. 23, 1943 UNITED STATES ?ATENT OFFICE il Claims.

- This invention relates to circuit controlling switches, and more particularly to a pneumatic switch device of a quick acting type.

The successful operation of electropneumatic brake systems for trains necessitates the provision of 'uidpressure responsive switches that must be rugged in construction and positive in operation. Such switches are generally designed to move from one position to another with a snap action, and are also usually designed for operation in response to different fluid pressure, within a given range. While such switches therefore must be adjustable, it is occasionally difficult to adjust such a switch so that it will respond to a desired pressure without causing vibration or chattering of the associated contact elements at they moment contact is made or broken. Vibration and shocks transmitted to the switch while the vehicle is in motion are often effective to increase this undesirable operating condition.

It is an object of this invention to provide an improved pneumatic` switch device of novel construction, the associated elements of which are designed to produce the desired quick make and break operation of the contact elements, while preventing interference with operation of the switch due to the condition just mentioned.

Another object of the invention is toprovide a pneumatic switch device having a snap acting contact carrying element, which is counterbalanced so that shock during operation cannot inn duce reaction of the associated contact elementsr lsuch as might lresult in undesired vibration of the contact elements.

Other objects and advantages of the invention will appear in the following more detailed description thereof, taken in connection with the accompanying drawings, in which Fig. 1 is a top or plan view, partly in section, of a pneumatic switch device constructed in accordance with my invention;

Fig. 2 is an elevational sectional View of `the switch device shown in Fig. 1;

Fig. 3 is a sectional view similar to that shown in Fig. 2, illustrating the movable elements of the switch device in circuit closed position; and

Fig. 4 is a fragmentary sectional View taken along the line 4-v-4 of Fig. 3.

Referring to Fig. 2 of the drawings, the `switch device comprises a casing structure which includes a bracket section I0, a base section II secured thereto by means of bolts such as that indicated at I2, and a cover section I3 that is also secured to the bracket section by bolts such as I4. Clamped between the bracket section `Ill 55 of the casing and theA base section II is a flexible diaphragm i8, which has formed at the lower side thereof a pressure chamber I9 to which fluid under pressure may be supplied by way of suitable communications including a passage 2S. Formed in the base section Il above the diaphragm I8 is a chamber 22, in which is disposed a follower element 23 having a circular portion engaging the diaphragm and a stem portion 24 whichr isf slidably mounted in a suitable bore formed in an upwardly extending portion 25 of the base section. The follower element 23 has formed thereon an annular rib 2l which is engageable with the upper wall of the chamber 22 for limiting upward movement of the diaphragm I8 and follower element, as hereinafter explained.

A horizontally disposed bar 2:?A is carried on the upper end of the stem portion 2.4, and is secured in place by means of a pin te, which is fitted into a suitable bore formed in the stern portion. The bore formed within the extension 25 in which is mounted the stem portion 24 of the follower element terminates in alateral slot 32, which is adapted .to permit upward movement of the stem portion and thefbar 2.9. For biasing the assembled bar 29, follower element 23, and diaphragm i8 toward the normal position as shown in Figi. 2, there is provided an adjustable spring assembly comprising an annular spring kseat member 34 that is disposed in engagement .with the horizontal bar 29, a stationary spring sea-t .element 35k mounted on a vertically disposed post 36 having screw-threaded connection with the extension 25, and a coil spring 31, which is interposed between the two spring seat elements. The upper end of the 4post 35 is suitably threaded to receive a pair of lock nuts 38 for positioning the upper spring seat element 35 to provide the desired. tensioning of the spring 3l.

Formed on the base section il of the casing structure are a pair of spaced lugs 4G, which are suitably apertured` to receive a horizontally dis posed pin 4I, the .ends of which extend outwardly of the lugs and are fitted with cotter pins 42 as may be seen in Fig.f4. A Ushaped link element 43 is pivotally mounted on the pin 4I intermediate the lugs 401. Upwardly extending arms 44 are formed in the link element 43, and are provided with bores through which is fitted another horizontally disposed pin 4f, which may be of the same dimensions as the pin 4I. Cotter pins 41 are preferably provided for retaining the pin 46 in place.

Disposed in surrounding relation with respect tothe vertical portion 25 of the base section Il is a bail lever 59, which as best shown in Fig. 1 has spaced lateral portions 5| pivotally mounted on the respective ends of the pin 29, and which also has a tubular end portion 52 that is journaled on the pin 46, intermediate the arms 44 of the link element already described. Also journaled on the pin 45 is a bifurcated contact carrier lever or frame 55, comprising spaced side portions 56 which straddle bail lever 59 and terminate, beyond the pivotal connections with the ends of pin 46, in a counterweight portion 51.

As best shown in Fig. 1 of the drawings, the side portions 56 of the contact carrier frame 55 are inswept adjacent the ends thereof opposite the counterweight portion 51, which ends are joined by a head portion 60. Transversely mounted in a lug 6| carried on the head portion 60 is a pivot element 53, to which is pivotally connected an insulating block 64, which serves as a movable contact support. It will thus be seen that the contact carrier frame 55 is pivotally mounted in substantially balanced relation, the end thereof terminating in the head portion 60 and the opposite end provided with the counterweight portion 51 having about equal moments with respect to the fulcrum pin 46. Consequently any jarring of the switch device during operation of the vehicle on which it is mounted will be ineffective to interfere with the positioning of the contact carrier frame, as hereinafter explained.

The insulating block 64 has formed thereon upper and lower abutment surfaces 61 and 68, which are respectively aligned with similar surfaces 59 and 10 formed on the head portion of the contact carrier arm 55. A coil spring 12 is interposed between the head portion 60 and the insulating block B4 at a point above the pivot pin 63 for urging the insulating block into the normal position, in which it is illustrated in Fig. 2 of the drawings, the abutment surfaces 68 and 'IU being then engaged. Mounted in a laterally disposed recess 15 formed in the upper surface or the insulating block S4 is a contact bar 16, which is adapted to rock slightly in the recess and has end portions extending outwardly at opposite sides of the block, as best shown in Fig. 1. 'Ihe contact -bar 16 is held in place .byA a vertically -arranged pin 11, which is fitted with a lock washer 18 for limiting upward movement thereof. A coil spring 88 is interposed between a shoulder 8| formed within the block 64 and a washer 82 which is fitted on the pin 11 and engages the lower surface of the contact bar 16, the latter element being thereby normally maintained in the position shown in Fig. 2, it ibeing noted that a space is thus normally left between the contact bar and the adjacent surface of the recess 15.

interposed between and operatively connecting the bail lever 55 and the head portion 60 of the contact carrier lever 55 is a toggle assembly, which comprises a member 85 having a head 89 pivotally engaging a pin 81 carried on the end of the lever 50, a similar element 9U having a head 9| engaging a pin 92 carriedby the head 4portion B0, and a coil spring 95 which is interposed between the respective heads 9| and 86 for urging the two elements apart. It will be noted that the element 90 has a stern portion lwhich is slidably tted within a bore formed in the element 85.

As shown in Fig. 2, when the pressure chamber I9 is vented and the diaphragm I8 and follower member 23 are thus disposed in the lowermost position, the bail lever 5,0 `and the two assembled elements 85 and 90 are held below their dea-d center position, so that the spring 95 is effective to urge the head portion 50 of the contact carrier frame 55 upwardly into circuit opening position. In this position of the frame 55, a pair of lugs |00 formed thereon are held in engagement with stationary stop elements I9I extending from the base section I I, for dening the uppermost position of the assembled elements. With the switch device thus disposed in circuit opening position, the contact bar 16 is held above and out of engagement with a pair of stationary contact elements |03, which are fixed to and extend inwardly from suitably insulated support ing posts |04 carried by the base section I I of the casing structure. The respective contact elements |03 are adapted to be connected through the medium of wires |05 into the circuit controlled by the switch device.

In operation, when the pressure of fluid supplied to the :pressure chamber I9 is increased suiiiciently, the diaphragm I8, follower element 23, bar 29 and spring seat 34 are moved upwardly against the opposing force exerted by the coil spring 31, while the bail lever 50 connected to the bar 29 is turned in a clockwise direction about the pin 46. .At the same time, the pin 81 carried on the end of the bail lever 50 operates the element 85 in telescoping relation with the element 90, overcoming the force of the spring 95, so that the associated elements and the connected bail lever 50 are moved toward their dead center position.

As the diaphragm I8 and the follower element 23 are further moved upwardly and approach the position illustrated in Fig. 3 of the drawings, wherein the rib 21 will engage the upper wall of the chamber 22, the toggle assembly Comprising the elements 85 and 9D together with the bail lever 59 are carried beyond the dead center position, whereupon the spring 95 becomes eiective to exert a downward force against the pin 92 carried by the head portion 60 of the carrier lever 55. The carrier lever or frame 55 is then quickly moved into the position illustrated in Fig. 3' under the force exerted by the spring 95 through the mediurn of the element and pin 92, and as a resul-t the contact bar 16 is brought into engagement with the fixed contact elements |03 for closing the associated electrical circuit. As the contact elements are thus brought together, the insulating block S4 is rotated slightly about the pivot element V63 and against the opposing force of the spring 12, so that the electrical connection between the contact elements is made with a limited wiping action to insure perfect contact. At the same time, the inertia of the counterweight portion 51 of the contact carrier frame 55 prevents chattering or vibration thereof during this operation.

When iluid under pressure is subsequently released from the pressure chamber I9, the spring 31 is rendered effective to move the spring seat element 34, bar 29, follower element 23 and diaphragm I8 downwardly, the bar carrying with it the bail lever 50, which turns in a counterclockwise direction about the pivot pin Mi. Upon movement of the toggle assembly comprising the bail lever 50 and the two elements 85 and 90 below their dead center position, the spring quickly expands and forces upwardly the pin 92 and head portion 60 of the carrier frame 55, which is thereby rotated about the pin 46. The connection between the fixed contact elements |03 and the contact bar 82 is thus quickly broken, as the several elements of the switch device once again assume the position illustrated in Fig. 2.

It will be understood that the circuit opening operation of the switch device, as just explained, is accomplished Without the production of any undesirable vibration of the movable contact element as it is withdrawn on the fixed contact elements, due to the novel construction and arrangement of the parts including the counter balanced contact carrier frame E5.

If desired, the contact elements of the switch device may be reversed to render the switch device operable to circuit closing position, rather than circuit opening position, upon an increase in the pressure of yfluid in the pressure'chamber i9. The change may be performed by removing the pivot element 63 connecting the insulating block 611 to the head portion 6!) of the carrier frame 55, rotating the insulating block and the elements mounted therein 180, and again fitting the pivot element 63 into place for securing the parts together. The posts IM are then replaced with longer elements of similar construction that will support the fixed contact elements l3 in the proper position above the movable contact bar 16, and the switch device is then in condition for operation from circuit opening position to circuit closing position when fluid under pressure is supplied to the pressure chamber I9.

It will thus be seen that the improved pneumatic switch device co-nstructed in accordance with my invention includes novel features of construction rendering the device operable with the desired snap action and without vibration of the contact elements, and that the various parts of the device are readily adjustable to permit use of the switch device to meet the exacting demands encountered in railway electropneumatic brake service.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. An electric switch device comprising, in combination, stationary contact means, movable contact means cooperable therewith, a pivotally mounted contact carrying member having one end connected in supporting relation with said movable contact means and having a counterweight portion carried on the opposite end, a spring, a movable abutment subject to opposing forces of said spring and of a control fluid pressure, and snap acting toggle lever means operable by said abutment for shifting said contact carrying member to force said movable contact means into and out of engagement with said stationary contact means.

2. An electric switch device comprising, in cornbination, stationary contact means, movable contact means cooperable therewith, a pivotally mounted contact carrying member having one end connected in supporting relation with said movable contact means and having a counterweight portion carried on the opposite end, a spring, toggle lever means subject to the force of said spring and operable when forced past a dead center position to shift the contact carrying member to effect quick movement of said movable contact means into or out of engagement with said stationary contact means, and actuating means for operating the toggle lever means.

3. An electric switch device comprising, in combination, stationary contact means, movable contact means cooperable therewith, a pivotally mounted contact carrying member having one end connected in supporting relation with said movable contact means and having a counter- Weight portion carried on the opposite end, a

spring, toggle lever means subject to the force of said spring and operable when forced vpast a dead center position to shift the contact carrying member to effect quick movement of said movable contact means into or out of engagement with said stationary contact means, and iiuid pressure responsive means operatively connected to said toggle lever means.

4. In a pneumatic switch device, in combination, fixed contact means, Contact carrier means having a head portion at one end and a counterweight portion at the other, said contact carrier means being pivotally mounted intermediate its ends, movable contact means secured to said head portion and operable by said carrier means into and out of engagement with said xed contact means, a toggle lever assembly including an operating spring for effecting quick movement of said carrier means in either direction about the pivotal connection thereof, and actuating means for initiating operation of said toggle lever assembly.

5. In a pneumatic switch device, in combination, fixed contact means, contact carrier means having a head portionat one end and a countei-weight portion at the other, said contact carrier means being pivotally mounted intermediate its ends, movable contact means secured to said head portion and operable by said carrier means into and out of engagement with said xed contact means, a toggle lever assembly including an operating spring for effecting quick movement of said carrier means in either direction about the pivotal connection thereof, adjustable spring means cooperable with said toggle lever assembly for shifting said carrier means in one direction, and fluid pressure responsive means cooperable with said toggle lever assembly for shifting said carrier means in the other direction.

6. A pneumatic switch device comprisinga casing structure, fluid pressure responsive actuating means mounted in said casing structure, stationary contact means carried by said casing structure, a contact carrier frame pivotally mounted in said casing structure and having a counterweight portion disposed at one Side of 'said pivotal connection and a head portion at the other side thereof, movable contact means removably connected to said head portion and rarranged for movement into and out of engagement with said fixed contact means, and spring biased toggle means arranged within said carrier frame and operative in accordance with movement of said actuating means to effect quick operation of said carrier frame.

7. In a pneumatic switch device, in combination, a casing structure, contact means fixed thereto, a movable link member journaled on said casing structure, a contact carrier member having a head portion at one end and a counterweight portion at the other, a pin pivotally connecting said carrier member to said link member, movable contact means secured to said head portion and operable by said carrier member into and out of engagement with said fixed contact means, a toggle lever assembly including an operating spring for effecting quick movement of said carrier member in either direction about the pivotal connection thereof, and actuating means for initiating operation of said toggle lever assembly.

8. In a pneumatic switch device, in combination, a casing structure, contact means xed thereto, a movable link member journaled on said casing structure, a contact carrier member having a head portion at one end and a counterweight portion at the other. a pin pivotally connecting said carrier member to said link member, movable contact means secured to said head portion and operable by said carrier member into and out of engagement with said xed contact means, a toggle lever assembly for effecting quick movement of said carrier member in either direction about the pivotal connection thereof, said assembly including an operating spring and a rockable toggle lever journaled on said pin, and actuating means cooperative with said rockable toggle lever for initiating operation of said toggle lever assembly.

9. An electric switch mechanism comprising a base, stationary contact means mounted thereon, a rockable link element journaled on said base and carrying a pivot pin, a contact carrier pivotally connected to said pivot pin, movable contact means supported by said contact carrier remote from said pivot pin and in cooperative relation with said stationary contact means, a toggle member also journaled on said pivot pin, toggle spring means connected to said toggle member and to said contact carrier for operating said contact carrier in either direction about said pivot pin, and actuating means for initiating movement of said toggle member.

CECIL S. KELLEY.

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