US1699792A - Quick-acting switch - Google Patents

Description

Jamzz, 1929. 1,699,792

E. P. LARSH QUICK ACTING SWITCH @www Jan. 22, 1929. 1,699,792 E. P. LARsH QUICK ACTING SWITCH Filed Oct. 19, 1925 2 Sheets-Sheet 2 Patented Jan. 22, 1929.

UNlTElll STATES PATENT OFFICE. i

EVEREIT P. LARSH, F DAYTON, OHIO, .ASSIG'NOR TO THE MASTER ".IILIE.C'JILIGOOM-` PANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.`

QUICK-ACTING SWITCH.

Application le. October 19, 1925. Serial No. 63,393.

My invention relates to electric s'vvitches and more particularly to an automatic quick acting cut-out for alternately opening and closingy electric circuits under influencent variations of pressure, temperature or intensity of an actuating medium. lhile invention herein shown and described more particularly in its application to electric switches, it will be understood that the same actuating mechanism [may be utilized for opening and closing a valve, shifting a clutch intoor out of operative position, or to perform other analogous operations. a

A very usual application of the present type of automatic cut-out isin theeontrol of motor driven pumping systems for Water distribution. ln such installations, it is customary to store Water and air in a suitable tank or reservoir, by means of a motor driven supply pump, discharging under sufhcient pressure that the water may be carried through the pipe lines of the distribution system by the influence of air pressure Within the tank or reservoir. Control or cut-out devices are utilized in such systems to maintain the pressure Within prescribed limits by setting the supply pump in operation when the pressure Within the tank and distribution system falls below a predetermined range and to arrest the supply pump when the pressure has been restored, to a predetermined maximum degree. In many instances these control devices have been of a slow actingtype, having a tendency to dwell or lag in a partially operated `condition. The present construction is designed to not only overcome this objection by providing a construction which will maintain a full or even increased pressure upon the contact until the instant of breakage, Whereupon the disconnection or breaking movement vvill be efected with a quick snap-over action,eliminating any tendency to spark or arc between the contact points.

Theobject oi the invention is to simplify the structure as Well as the means and mode oi! operation of such quick acting cut-out mechanisms, "whereby they Will not only be cheapened in construction, but will be more efficient in use, positive in operation, uniform in action, automatically controlled, and unlikely to get out of repair.

A 'further and important object of the invention is to provide such a mechanism having a minimum number ofparts so shaped and designed that they may be economically manufactured by stamping` orpunch press operations and so arranged as to facilitate assembly. Simplicity of construction and economy of manufacture are of prime importance.

With the above' primary and other incidental objects in vie\v,as vvill more fully appear in the specilication, the invention con`- sists of the features of construction, the parts and combinations thereof, and the mode of operation or their equivalents as hereinafter described and set forth in the claims.

Referring t-o the accompanying drawings, wherein is shown the preferred, although obviously not necessarilythe only form of embodiment of the invention, Fig. 1 is a side elevation of the assembled mechanism, showing the switch in its open or retracted position. Fig, 2 is asimilar view illustrating the relative relation of the parts upon reversal of the movement, the switch being shown in its operated or closed position.

Fig. 3 is a detail elevation of the operating members, viewed at right angles from the left in Figs. l and. Fig. l is a detail perspective view of the actuating parts in' their assembled relation. Fig. 5 is a detail perspective vien7 of the several operating parts disassembled. `lligs. G, and "-8 'illustrate different modes of operation, to Wit:` iloat actuated, thermostatic operated and by use of a sylphon or expansion chamber, respectively. Fig. 9 illustrates the use of rigid contact carrying arms in lieu of the spring arms of the primary construction. Figs. l0 and l1 illustrate the Vapplication of the apparatus to the operation of a valve and a clutch respectively. Like parts are indicated by similar characters of reference throughout the several views. y

The operating mechanism of the present cut-out is enclosed Within a housing or case l, in the base of which, there is provided an expansible chamber 2, formed by the transverse diaphragm 3, the margin of which is provided with `a bearing plate l, provided with a central boss '7, engaged by the arm of the rock lever. The arm 5l of the rock lever is thus `sulaj eeted to. yupward pressure of the diaphragm, and is .also subiect to yielding resistance of a helical spring 8, bearing upon the outer end of the lever kin oppos1- tion to the influence of the diaphragm. lhe tension or resistance of the spring 8 maybe regulated by a screw stud 9 engaged in the upper portion of the nhousing '1,;and bearing upon a disc or head 10, against which the upper end of' the spring reacts. For convenience of assembly the bell crank lever 5 'is provided with a notch 11, at its inner angle for engagement upon the trimmen stud, or shatt L Pivoted `upon the same Y trunnion stud t and positioned within the extends.

channel of the upstand'i'ng `arm 5 oi? the bellcrauk lever,` is acam arm 12, having oppositelgy inclined or divergent cam faces at its upper end. The cam arm 12 "is provided with L ilotcli or recess 13, into which the upperend of the arm 5 oi: the bell crank lever YThis notch 13` of sufficient dimension to permit a limited play or rela tive movement of the cam arm and bell crank lever relative one to the other, but

t beyond which limited range of movement,

'the cam arm` and bell Crank level: move in unison in either direction.

The movable switch contacts 14 are carried upon spring` arms 15, which are. flexed to. and `iro to carry the contacts into and out of electrical engagement with stationary contacts 16, mounted upon a wall or plate 17 of ber Or other insulating material, se-

cured within `the housing l. The spring 15 are termed at midlength point with Vbights 1S, in which is engaged a transverse tie-rod 19. This tie-rod 19 is preferably provided adjacentV its. ends with shallow grooves,4 within which the bights of the re s ect-ive springs 15 are contracted, to locate tie springs u on the tie rod and secure them in relationA t rewith. Engaged upon the tie rod. 19 intermediate the spring ai'tn'is l5 is a plunger member 20, capable of to and fro movement in` unison with the flexing of `the spring arms 15, necessary to make and break the electrical contact between the con,- tact heads. 14 and 16, and also capable oli' `oscillatory or rocking movement about the tie rod 19. The plunger 20` carriesfa roller 2l, which is engageable lrst with one inclined side and then with the other of the .upper end of the cani bar 12J. The plunger member 20 isdepressed and the roller 21 `held in contact with the engaged inclined face of the cam bar and is forced downward thereon by thepressuae of the helical spring 22bearing at itslower end upon the plunger member 20 and reacting at its upper end against .the interior ofthe top of the housing l. The camming action of the inclined face oppositely inclined head of the arm.

ofthe cam bar 12 as theroller 20 is forced downwardly thereon under influence of the spring 22 tends to move the plunger 20 to `and fro to open or close the switch Contact. In the opening movement or retraction of' the plunger 20 as shown in Fig. l, its movement is Vlimited by the stop stud 23, projecting from the housing l. In its opposite or closing movement, as illustrated in Fig. 2, the movement of the plunger is limited only by the contact pressure of the switch contact heads 14 and 16. The differential mechanism is actuated by variations or' pressure within the diaphragm chamber 2, which is connected' with any suitable body of lluid under fluctuating pressure. This diaphragm chamber 2 may be connected with the storage reservoir of a water distribution system, or it may be in communication with a body of expansible and contractible `fluid subject to variations of temperature as for instance, inV a refrigerator, whereby the switch will be operated to stop and start the refrigerating apparatus. In lieu of such pressure variations, the apparatus may be actuated 'by a rise and fall of a float, or by the tension of a thermostatic bar or the like.

Assuming the parts to be in the position shown in Fig. 2, any upward pressure upon the arm 5l of the bell crank lever 5 tends t0 oscillate the bell crank lever toward theright against the yielding resistance of the spring 8. The upper end of the arm 5 of the rock lever being engaged in the notch 13 of the cam arm l2, carries with it the cam arm, the inclined upper end of which bears against the roller 21 ol' the plunger 20. This camming pressure of the inclined' head of the arm 12, upon the roller 21, not only tends to move the plunger 20 toward the right and thereby increase the Contact pressure between the switch contacts 14: and 16, but it exerts an upward or rocking influence upon the plunger 20, against the yielding resistance of the spring 22. It will be noted that the downward pressure of the spring 22 is in a somewhat inclined direction,` in which it adds its influence to that of the cam in holding the switch elements in engaged relation. The contact elements are thus held in tight engagement with gradually increasing pressure until in the movement of the rock lever and cam arm, the roller 2l reaches the apex oit the To prevent any dwell or lag of the parts at this stage, and to afford a quick snapfozver action, by which the contact is definitely broken without hesitation, the cam arm 12 is permitted a slight movement independent of the rocker arm, within the limits afforded by the clearance of the notch 111. The apex of the cam arm is thus passed entirely past the roller 21, and the roller 2l is forceddown the opposite incline of the head of the cam arm, by the reaction of the spring 22, which lll .Uli

l ce

1 plements that of the diaphragm pressure in overcoming the resistance of the main spring S, and completing the retractive movement of the v )lunger 20 and the spring switch arms 15. The parts at their final movement as-l sume the position shown inFig. 1. Upon lecrease of pressure beneath the diaphragm,

the expansive influence of the spring 8 is exerted to rock the `bell crank lever 5 in the opposite direction against the yielding resistance of the spring 22, which is compressed by the camming action of the inclined head ot the cam arm 12 uponthe roller 21, as the roller andplunger 2O are elevated until the apex of the cam head passes beneath the roll er. rlhereupon the cam arm is again permitted a slight independent movement suilicient to obviate any tendency to lag and presents thejopposite inclined face of the cam head to the roller. ln its movement to andl fro, the plunger 2O passes a dead center relation relative to the spring 22, so that the spring 22 exerts its influence diagonally, first in one direction and then in the other, to hold the switch contact open or closed. ln this manner, the cam action and spring tension are complementary of each other, and operate in unison to e'ect instantaneous engagement and disengagement and to hold the parts securely in their operated positions. lil/'hile the several operating` parts may be produced by any suitable method as for instance by casting, for economy of manufacture, they are preferably formed by sheet metal stamping as illustrated in the draW- ings. Likewise, for economy of manufacture, the movable arms 15, are made spring arms, and are included in the electrical circuitto be opened and closed, it will be ob vious that these arms may be made rigid and pivoted at their" lower extremity, and be made to carry either yielding Contact heads, a valve or a clutch operating means as shown in the severaldetail views, Figs. 9, 1() and 11. liilreivise, there has been shovvn in Figs. 6 and 7, means for operating the bell crank lever by the rise and fall of a float or by the distortion of a thermostatic bar, in lieu of the fluctuations of the diaphragm 3.

From the above description `it Will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but Which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts Without departing from the principle involved or sacrilicingany of its advantages. y i

While in order to comply with Ythe statute the invention has been described in language more or less specic as to structural features, it is to be understood that the invention is not limited to the specific details shown, but that the means and construction herein disclosed comprises the. preferred form of several modes of putting the invention into effect and the invention is, therefore,claimed in any of its forms or modificationsWithin the legitimate and valid scope of the appended claims.

Having thus described my invention, I

claim:

1. `In a device of the character described, a pressure operated prime mover, a cam member carried thereby having convergingl cam faces and capable of limited to and fro movement `independent ofthe movement of the prime mover, an alternator member riding uponthe cam member,a spring inclined to the path of travel of said alternator in different directions when the alternator is atl opposite limits of its stroke and further pressing an alternator memberinto engagement with first one, and then the other of said converging `faces of the `cam member, said converging faces being alternately presented n engagement With an alternator member by the movement of the prime mover, the independent movement of the cam member serving to shift said member past dead center position, a member to be moved to alternate positions `connected `with said alternator member and pressure means controlling the movement of the prime mover.

2. In a device ofthe vcharacter described, a member to be moved to alternate positions, a pressure actuated main operating lever, a cam lever pivoted concentric with the main lever, a looser coupling between the main lever and the cam lever by which said levers are caused4 to move in unison in either direction throughout the major pon tions of their strokes, but permitting a limited independent movement of said levers relative to each other, a reciprocatory actuating member spring pressed into engagement With the cam lever and operatively connected With the member to be moved, the convergent cam faces of the cam lever being alternately presented in operative engagement with the actuating member by the `to and fro movement of the main lever and cam lever.

3. In a device of the character described, a member to be moved to alternate positions, a pressure operated prime mover, a cam member carried thereby having convergent cam faces, said prime mover and cam member being movable to and fro in unison throughout the major range of their strokes butl capable of limited independent `Inovement relative to each other, alternating actuating member for the member to be moved, a spring :pressing said alternating member into operative engagement with one -of the converging cam `faces of said cam member said alternati fr actuating member beine movable to and nigio past dead center relation with said spring whereby said spring is caused to act first inone direction and then inthe other upon said alternating member, said cam faces being alternately presented in operative `relation with the actuating `member by the to and fro movement of the cam member to effect alternating shifting oi' the actuating member and with it the member to be moved.

4:. In a device of the character described, the combination Witha member to be moved to alternatev posi-tions, of an alternating actuating member therefor, a double faced cam over which the actuating member rides in its alternating movement, 'a spring for effecting `operative `engagement of said alternating member with first one face and -then the other of said `cam said alternating member being movable to and fro past dead center relation with said spring whereby the spring tends to hold said alternating member at either limit of its stroke and pressure operated `means for relatively adjusting the'` cam `and alternating member to eil'ect reversal of. the member.

5. In a device of the character described, a member to be moved to alternate .positions, an actuating member there-tor., a cam member having converging faces alternately in engagement with the actuating member, a` spring tending tomove the actuating member along the `engaged tace of the cam the actuating member being movable toizand fro past` dead center relation with said spring, and means for shitting the cam member `to present `the converging faces thereof alternately in engagement with the actuating member whereby the actuating member `Will be moved alternately in reverse directions under infiuence of the spring the dead center position oi' said cam member and said spring being passed substantially simuitaneously Vby said? actuating member.

6. In a device of the character described,

rename a member` 'to `be moved tofalternate positions, a bell crank lever, one arm of which is channeled, .a cam lever concentrically pivoted witbthe bell cran-k lever and seating within the channeled `arm ofthe bell crank lever, means for limiting the relud tive oscillation of the cam lever and the bell crank lever beyond `the range of which independent movement smid levers move in unison, an actuating member for the member to be `moved `having operative engagement with the cam `leven, in di'crenrt `positions oi' adjustment of the latter' to etlect shifting movement olf the actuating member in diferent directions, and means for oscillating the bell crank lever in alternate directimis.

7. In a device of the character described, a member `to be moved to alternate position-s, main operating lever, 4a cam lever pivoted conzcentricaily with the main operating lever, means for limiting the relative oscillation of the main lever and the cam lever beyond the range of which independent movement, the levers move iny unison, an actuating member for the member to be moved having operative engagement with the cam lever in dili'erent-positions of adjustment of the latter', to effect shifting Inovement oi' the actuating member in different directions, and means for oscilllating -tlre main operating lever.

8. In a device oaf the character described, a member to be moved to alternate positions, a main operating lever, a camY lever pivoted concentrically with the mainoperating lever, and having therein a recess and an extension upon the 4main Vlever projecting into said recess which is ci snlcient extent to permit a limited degree of lost motion therein, beyond the range of which lost mot-ion the levers move in unison, an actuating member for til-'1e member to be moved having operative engagement with the cam lever in different positions of justmentof the latter, to eiect shifting movement ofi" the actuating member in different directions, and means for oscillating the main lever. i

In testimony whereof", -I have hereunto set my hand this 28th day of September A. D.

1925. P. LRSH.

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