US2522278A - Cam type limit switch assemblage - Google Patents

Description

Sept. 12, 1950 N. H. KOERTGE Er Al.

CAM TYPE LIMIT SWITCH ASSEMBLAGE 2 Sheets-Sheet l Filed Nov. l2, 1947 mum x/ m l l l l I u l l,

'Illllllllln l g lib ZI I7 -24 N. H. KOERTGE ET AL CAM TYPE LIMIT SWITCH ASSEMBLAGE Sept. 12, 1950 2 Sheets-Sheet 2 Filed Nov. Al2, 1947 JNVENTORS @ZM/m Afro/6Min?.

Patented Sept. 12, 1950 2,522,278 oAivrfTvrE LIMIT SWITCH As SEMBLAGE Nobel H. Koertge, Glen Ellyn, and Edward L. Bucks, Aurora, Ill., assignors to Furnas Electric Company, Batavia, Ill., a corporation'of Illinois Application November 12, 1947, `Seri-al No. l185,254

Our present invention relates generally to improvements in electric switch assemblages, and relates more particularly to various improvements in the construction and operation of limit switches of the type wherein the switch contacts are mechanically actuated with the aid of vcam mechanism or the like, as illustrated in Patent No. 2,289,643, dated lJuly 14, 1942, to W. C. Furnas and J. H. Hansen.

A primary object of the present invention is to provide an improved cam type limit switch which is extremely simple, durable, land compact in construction, and which is moreover highly efficient in use and ilexible in its adaptations.

A more specific object of this invention is to provide an improved limit switch unit which is positive, dependable and rapid in action and which is moreover composed of relatively few simple parts.

Ano-ther specic object of the invention is to provide 'an improved neat and compact limit switch assemblage which can be quickly and con# veniently adjusted to eiectively meet various conditions of operation by merely changing the relative positions of simple parts, or by replacing one of the Darts by a correspondingly simple element.

Another specinc object of our invention is to provide an improved mechanically actuated limit switch wherein the switch contacts, operable to produce a variety of actions, are actuated by improved cam mechanism provided Vwith integral limit stops.

A further specific object of our present inven.- tion is to provide an improved limit switch unit wherein the switch contact supporting block or housing is mounted in an improved and simple' manner on yan inverted U-shaped bracket or frame which `also serves to rotatably support the cam actuating shaft and its associated parts.

An additional specic object of the present invention is to provide an improved cam type limit switch unit which is composed of a minimum number of simple partsA -assembled and retained in assembled condition in a novel and improved manner, and which may be readily utilized either with or without the enclosing casing or housing.

Still another specific object of our present `in-j vention is to provide an improved cam type limit switch wherein the various parts may be sturdily constructed of sheet metal or the like and readily assembled at extremely low cost.

These and other specc objects and advanj tages of the invention will be apparent from the following detailed description.

A clear conception of the. several features con?v 4 Claims. (Cl. 200- 47 stituting ou1` presentI improvement, and of the mode of constructing and of utilizing improved Icam type limit switches embodying the inventionmay be had by referring to Vthe drawings accompanying andforming a part of this specification, wherein likereference characters designate the' sameor similar parts in the several views.

Figure 1 is an outside front view of one of our improved limit switches, showing the contact actuating cam assembled in Normally On position, and with a portion of the clo-sure cover having been broken away toy reveal internal structure and the retaining screw'for the cam actuating lever also having been omitted.

Figur'e`2 is a transverse vertical section through the switch assemblage, taken along the line 22 of Figure 1;

Figure 3 is a transverse :horizontal section through thel switch unit, taken along the irregular line 3-3 of Figure 1; f

Figure'4 is a front view of the normally yconcealed switch mechanism with the cam and its actuating lever movedto contact opening posi-` tion, the enclosing cover having been removed and portions having been broken away to reveal internal' and normallyv hidden structure;

Figure 5 is a `viewsimilar to that of Figure 1, but showing the contact actuating cam assembled in Normally Oi position;

Figure 6 is a front View of the assemblage'of Figure 5 showing the normally concealed switch mechanism ywith the cam and its actuating lever moved 'tocontact vclosing position, the enclosing coverhaving been removed and portions having been broken away to reveal internal and normally concealed structure; fFigure 7 is `a rear view of the switch contact assemblage of Figure 1, the casing or housing having been removed and portions having been broken away to reveal normally concealed structure; and.

y lFigure 8 is a 4transverse section through the switch actuating mechanism, taken along the linef-- of Figure 2, the actuating cam being shown in dot+anddash lines.

While the'various features of the present invention have beenshown and described herein as being especially applicable to a cam type limit switch of afparticular design and with special reference toPatent No. 2,289,643, dated July 14, 19.42, to W. C. Furnas and G. H. Hansen, it is not our'desire or intention to unnecessarily restrict or limit the scope or utility of the improved fea'- ture'fby reason of'such limited embodiment.

Referring to the drawings, the improved switch assemblage shown therein comprises, in general a main outer cup-shaped casing Ill having openings II in the rear wall thereof for effecting attachment of the switch unit to a suitable support, the casing or housing Il) also being provided with a detachable cover or closure plate I2; an inverted U-shaped supportingframe or mounting bracket i3 having one side or leg thereof removably secured to the rear wall of the casing by means of screws Ill, with the casing cover 1:2 being detachably attachable to the other side or leg of the U by means of screws I5; aswitchicontact supporting block 0r housing .I6 having atop plate il and being retainedrin assembled condition and rigidly secured to ,the ftop of the Ainverted U-shaped frame i3 by means of screws I8 or the like; a pair of laterally separated Vfixed contacts IS rigidly secured within the housing it and having terminal attaching screws a pair of similarly spaced Amovable contacts 2l exibly suspended from a nat guide ,bar22 .slidably penetrating the housing .i6 through anaperture .23, the Vcontalcts 2l coacting with la compression spring .2rd which reacts -against the plate I'I; a square or otherwise polygonally shaped spindle 25 havinga cylindrical `inner end portion26 bearing in a bore formed in the rear or inner wall yor leg of the U-shaped frame I3 and snugly embracedlby a spacer-bushing y2l; .acam 23, having a similarly shaped polygonal opening snugly received by the spindle 25 adjacent v.the cylindrical en d 26 and spacer .2l in Ithe plane of .movement of the contact Vcarrier bar 522-; Athe cam A2-8 being retained in position on .the spindle by ,a split retaining ring 29 ,or the li-ke; :a sleeve :or spacer-bushing 3e embracing the .polygonal portion of the spindle 25 and coacting at its inner end with the hat side of the cam 28, fthe spacer 3.6 being formed with ran annular groove near the outer end thereof for receiving a split retaining ring 3l which coacts with the 'inner ,surface of the front or outer wall or leg of the -Ushaped frame lf3 to retain-the various parts in assembled condition; an actuating lever v32 having la starshaped opening 33 at vone end ooactingw-ith the spindle 25 adjacent to the outer end of the sleeve or spacer 2f@ and having its opposite end provided with a-headed pin h34 `on-which :an'actuat-ing roller 35 is journalled; a screw 36 coacting with a threaded socket 2-1 in the outer end of the spindle 25 rand with a'lock washer 38 to retain the ,lever 32 in place on the spindle y2li; and torsionspring mechanism associated 'with the spacer 21 and cooperable with the cam 28 and'with the rear wall of the U-shaped frame ,I.3 as will be hereinafter more fully described, to effect automatic actuation of 'the ymovable contacts 2'I in various positions of adjustment.

`Most of the parts, including the main casing or 'housing zl, cover I2, supporting frame I3, switch contacts i9, 2i, cam 28, and lever 32,11nay all be readily formed of sheet metal and vvitlfithe aid of punches and dies and :these parts may be coated in a well known manner to prevent corrosion. The contact supporting block or .housing I6, top :plate il, and guide :bar `22 Vare preferably formed of durable insulating material, and the movable contacts 2I maybe flexibly suspended from a reduced upper portion of the carrier :bar 22, as shown in Figure 2,.so that proper engagement of these ymovable contacts with the fixed contacts fla is insured when the switch is closed. The dat lguide bar 22 should be freely slidable longitudinally in the contactsupportng block I E,

4 and this bar, together with the movable Contact 2 I, is constantly urged toward the cam 28 by the spring 24 which is preferably confined within a recess 38 in the top plate I'I, as clearly shown in Figure 2, in order to retain it in place. Obviously the main casing IU may also be provided with openings, not shown, in one side thereof through which the conducting wires may be introduced into the enclosure Vfor attachment to the terminal screws 20 in the usual manner, or the :main casing I6 may be omitted entirely and the frame I3 may be mounted directly to the desired support. It-is particularly important to note that the .top Iplate il is retained in position on the /fcontact block or housing i6 by the two screws I3 which ,also serve to rigidly secure the contact supporting block .I to the U-shaped frame I3, and this frame f3 vadditionally houses the cam 28 and fits associated mechanism and serves as a bearing for the rotatingparts.

AAshereinabove set forth, thecam 28 is provided with a polygonal opening ywhich snugly engages the ,polygonal spindle 25 and is retained on the polygonal portion of the spindle ..25 by thesplit ring 29,and the canrZi maybe removed endwise from the spindle vupon removal of the splitring 29 `and applied thereto in different angular positions-with respect lto the spindle axis. The cam 29 is approximately heart-shapei'as shown, and has'a pointed lobe iii and two similar side lobes lli; and this cam is also provided with two integral tabs bent inwardly or rearwardly to vvform ears 42, `each ear being formed between one of the side lobes M andthe centrallobe-Liil. When the .cam 2B is :applied to the shaft-or spindle 25 as shown in Figs. l yand 2, 'with the lobe 4B directed downwardly, themovable contacts 2l will be normally maintained vin-closed position by the action of the spring 211 and will be moved toppen positionfagainst the :action of this spring by coactionuvithone or the other oi the -lobes il upon oscillationlofthe cam 28 in either 'direction'from central position as clearly shown in Fig. f4. 'To provide la positive safety stop 'for limiting the extent of swing of the Vcani 28, the rear wall or leg of the U-s'haped frame I3 is vformed with an integral forwardly-bent tab forming a stop lug 43 :engagea'ble .with the years or abutments 42 upon loscillation of the cam 2B. When the cam 28 is `reversely applied-to the spindle 2d-as shown in Fig. '15., iwith the central lobe lll), directed inwardly, the movable contacts 2l will normally-be heldin open position by the lobe d of the cam 28, `and will be moved to closed position bythe action Vof the spring 24 when the cam 28 isoscillated in either direction Avfrom central position, andthe stop lug 'A3 will `likewise coact with the ears `l2 of the cam to :positively limit the movement of the cam28.

As hereinabove set forth, the rear wall or Aleg ofthe iii-,shaped frame SI2 is formed with 4abore adapted to receive and serve asa bearing for the cylindrical end portion 126 of the spindle 25,:and this cylindrical portion 26 of the spindle also r carries the spacer 2.7 4and 'the split retaining ring 29. 'The sleeve or spacer 3@ which embraces the hexagonal aportion of the spindle 25 serves lprimarilyto retain 'the can1-281againstthe retaining ring 29 and in proper position `with respect tothe bar `22, and 'this spacer snugly 4engages the corners of the hexagonal shaft portion. Itshould be noted `that the sleeve or spacer 32 is retained in ,position within the U-shaped -frame I3 and against the at side of the cam 28 :by Ithe split ring 3J Ywhich coacts with the lfront leg `or Wall ofthe frame I3, and lsince the other iiat side the cam 28 coacts with the ring 29 carriedA by the spindle 25, the entire contact actuating mechanism is Iproperly maintained in position within the lobe 40 of the camvv 23 inengagement with the frame I3. The star-shaped opening 33 in the lever 32 is so formed that the lever may be apr plied to the polygonal portion of the spindle in various positions of angular adjustment about the spindle axis, and the spacer`3il 4also serves as an abutment for the lever 32 when it isv applied to the spindle 25. It is thus apparent that they actuating roller and lever 32 may be associated with the polygonal spindlev 25 in different angular positions relative to the cam 2S, and the cam may likewise be associated with the same spindle in various angular positions, thereby pro-- viding a highly ilexible assemblage. When the lever 32 and the screw 35 and lock'washer38 have been appliedto the spindle 25, the actuating assemblage is complete; and it is important to note.

that the screw 3S not only holds the lever 32 in place on the spindle 25 but also draws the spindle 25 and the ring 29 forwardly against the cam 23 and spacer 30, thereby tightening the mechanism.

Referring particularly to Figs. 2, 3, '7 and 8, the improved torsion spring mechanism for automatically returning the cam 28 and lever 32 to predetermined position after oscillation of the lever 32 in either direction has been effected,

comprises in general, a torsion spring 44 einbracing the spacer 2l Yand having opposite outwardly projecting ends 45, 46 disposed on opposite sides of one of the ears 42 of the cam 28 and also colov acting with opposite sides oi a forwardly projectin'g lug 4l formed integral with the rear leg or wall of the U-shaped frame I3 outwardly beyond the plane of movement of the ears 42. The ears 42 of the cam 28 and the lug 4l may be provided with notches for retaining the spring ends 45, 46 in proper position; and when' the spindle 25 and cam 28 are oscillated in either direction after the device has been assembled, either spring end 45, 46 will be moved with the ear 42 away from the fixed lug or pin 4l, as shown by dot-and-dash lines-in Fig. 8, while the other end will be held against movement by the lug 4l, thereby causing the springjllitoy be wound aboutthe axis and placed under higher tension. When the oscillating forcev on the roller 35 and lever 32 has been released, the spring 44 will act quickly to return both of its ends 45, 46 into engagement with the lug or pin 4l, and the cam 28, spindle 25, and lever 32 will thus be automatically returned to initial or predetermined inactive position.

During normal use of the improved cam type limit switch, it is rst necessary to properly position the cam 28 with respect to its carrying shaft or spindle 25, and to likewise properly position the lever 32 with respect to the spindle 25, so as to produce the desired operation of the switch at the desired moment. If the cam 28 and lever 32 are secured to the spindle 25 in the relative positions shown in Figs. 1, 2, 3, 4, 7 and 8, the movable contacts 2I will normally be closed and in engagement with the fixed contacts I9 and movement of the lever 32 and roller 35 to either the full or the dot-and-dash positions in Fig. 4, will cause one of the lobes 4| of the cam 28 to engage the actuating bar 22 and to thereby open the switch. Upon release of the actuating the cam 28 and` 1ever'32 are'secured to the spindle 25 in the relative positions shown in Figs. 5 andy 6, thel movable contacts 2| will normally be out of engagement with the Xed contacts I9 with the actuating bar 22. If the roller 35 and lever 32 are subsequently shifted to either of the positions shown in full or in dot-and-dash lines in Fig. 6, the spring 24 will become active to move the contacts 2I to closed position in engagement with the xed contacts I8. Upon release of theI actuating lpressure against the roller 315, the torsion spring 44 will Ibecome quickly effective to restore the cam 28 and 'lever'32 to the position shown in Fig. 5. It should, of course, be understood that the position of the actuating lever 3,2 with respectvto the spindle 25 may be readily varied to suit different conditions Iof operationA by merely releasing the screw 36 land adjusting the lever 32 upon the spindle 25. Y

From thev foregoing detailed description,v it will be apparent that the present invention contemplates provisionof an improved cam type limit switch which is simple, compact, durable iny construction and highly efficient and flexible in use. The improved assemblage is` composed, of a minimum number of parts and may be readily dismantled and reassembled with the cam 28 so positioned that the switch is either normally on or normally off as desired, and adjustments the provision of integral ears 42 on the cam 28y and integral lugs 43, 41 on the rear leg of the frame I3 results in ,simple and eliectivemeans for limiting movement of the cam and for making the torsion spring effective to return the cam to neutral or predetermined position. The improved switch assemblage has proven highly satisfactoryin actual use andA mayibe manufactured and sold at moderate cost. While only one embodiment of the invention has been herein shown and described, it is apparent that the several features may be utilized in modified structures wherein it is desired to provide more than one cam of the same or different shapes to operate more than one set of contacts without departing from the present invention.

It should therefore be understood that it is not desired or intended to limit this invention to the exact details of construction or to the precise mode of use, herein shown and described, for various modifications may occur to persons skilled in the art to which this invention pertains.

We claim:

1. A switch assemblage comprising, an inverted unitary U-shaped frame, a polygonal spindle carried by said frame, said spindle having a cylindrical inner portion journalled for rotation in one integral side wall of said frame, a contact housing mounted directly upon the upper wall of said frame, a motion transmitting element slidably confined within said housing and movable through a guide slot in said upper frame wall toward and away from the axis of said spindie,A for; @Desmedt urging Seid element toward Said Spindle, a Cam filoulrtd- @61,1 the polygonal Por-111921 of, Soi-.d spindleforv flotation, therewith in the path of rnoveme'nt of said ele-- ment, said earn being adaptedcfor c oaction withy saidelernent tol move the'latterA away from the spindle axis, a lever mounted.' on the polygonal portionA of said spindle externally of said frarne, a sleeve` surrounding the polygonal portion ot said spindle and coacting with said earn and with saidlever to denitely space. saidoelernents apart, and means carried bysaid sleeve and coacting with the other side wall of s aid frame. to pre-l vent` displacement of said sleeve, said spindle and said earn from said frame. f

21.1 A switch assemblage comprising), a unitary sheet metal trarne having depending iront and rear integral walls and an upper transverse wall provided ,with a slot, a spindle passing through an opening in the feront depending wall and being journalled for rotation directly in the rear depending wall, said spindle having a lCylindrical journal portion and a polygonal; loortionextelding away from said cylindrical portion and outwardly beyond said trarne, a cam mounted upon one end of said polygonal portion adjacent s aid cylindrical journal portion and in proximity to said slot, a switch having a movable Contact4 carrying member passing through and guided in said slot ,and operatively cooperating with said cam, a lever mounted directly upon the protruding opposite end of the polygonal portion of Said spindle, and a sleeve surrounding said polygonal spindle portion and having one end in engage# ment with ,said cam while its other end passes throughand is conned against displacement by therront depending wall of said frame.

3. A switch assemblage comprising, a unitary sheet metal frame having depending front and rear integral Walls andan upper transverse Wall provided vwith a slot, a spindle passing through anopening inthe front depending Wally and being journalled for rotation directly in the rear depending wall, said spindle having a cylindrical journal portion anda polygonal portion,extendn ine away fromsaid Cylindrical portio.n and Out- Wafdlv beyond. Said from?, a .com mounted upon one end of said polygonal portion adjacent said Cylindrical journal portion and in proximity to said slot, a Switch having a movable contact..- Corrying member passing through. and guided 111 Said .Slot and operatively. ,cooperating Withs'aid cam, a lever mounted directlyupon the protrudying opposite end of the polygonal portion ot said spindle, Va sleeve surrounding said`"polygonal spindle vportion and having one endfn eng'algef` ment with said cam while vits other end passes through and is conned against displacement by the front depending wall of said frarne, Va cup# shaped outer'v casing secured directly tothe rear wall of said frame, and an enclosingcover secured directly to the front wall of said frame', said spindle and said sleeve projecting through an aperture in said cover and said lever being sefcured toV said spindle outwardly of thevcoyer.

- 4. A switch assemblage comprising, a unitary. sheet metal frame having dependingl front and rear integral walls and an upper transverse wall provided with a slot, a spindle passing through an opening in the front depending wall and being journalled for rotation directly. in the rear 'depending. wall, said spindle having a cylindrical journal portion and a polygonal portion extend'- ing away from said cylindrical portion'andoutwardly beyond said frame, aA sheet metalv Cain mounted upon one end of said polygonal portion adjacent said cylindrical journal portion and in proximity to said slot; said 'cam being provided with a pair of vspaced laterally projecting integral ears, a lug formed on the rear wall of said frame in the plane of movement of said cam ears and cooperable therewith to positively limit rotational movement of said cani in either directionI a switch having a movable contact-carrying member passing through and guided in said slot'and operatively cooperating with said cam, a lever mounted directly upon the protruding opposite end of the polygonal portion of said spindle, and a sleeve surrounding said polygonal spindle portion and having one end'in engagement with said cam While its other end passes through and is conned against displacement by the -front depending wall of said frame.

i NOBEL H, KOERTYGE. EDWARD L. RUCKS.'

REFERENCES omen The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,245,359 Smith June 10, 1941 2,289,643 Furnas et al July 14, 19,4;2 2,398,007 Hunter Apr. 9, 1946

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