US3104298A

US3104298A - Rotary cams and electric switches incorporating such cams

Info

Publication number: US3104298A
Application number: US851457A
Authority: US
Inventors: Arnold V Aldous
Original assignee: Automatic Electrical Control Co Ltd
Current assignee: Automatic Electrical Control Co Ltd
Priority date: 1958-06-14
Filing date: 1959-11-06
Publication date: 1963-09-17
Anticipated expiration: 1980-09-17

Description

Sept. 17, 1963 A. v. ALDous 3,104,298.

ROTARY CAMS AND ELECTRIC SWITCHES INCORPRATING SUCH CAMS Filed Nov. 6, 1959 2 Sheets-Sheet 1 INVENTQR V. AL nous Aways,

F IGZ.

ARNOLD A. V. ALDOUS Sept. 17, 1963 ROTARY CAMS AND ELECTRIC SWITCHES INCORPORATING SUCHA CAMS 2 Sheets-Sheet 2 Filed Nov. e, 1959 IsvVENTO/z.l ARNOLD V. ALDoug mijn United States Patent O 3 104,298 ROTARY CAMS AD ELECTRIC SWITCHES INCORPRATWG SUCH CAMS Arnold V. Aldous, Solihull, England, assigner to The Automatic Electrical Control Company Limited, Rushall, Walsall, England, a company of Great Britain Filed Nov. 6, 1959, Ser. No. 851,457 1 Claim. (Cl. 20u-153) This invention has reference to rotary cams and to electric :switches embodying and adapted to be operated by such cams.

rI'he principal object of the invention lis to enable the effective contour or length of lobe of a rotary cam to be adjusted at will so as to vary the angular rotary movement that need be imparted to the cam for actuating a device associated therewith and adapted to be actuated thereby.

A further object of the invention is to enable any desired number of cams to be mounted upon the shaft of a cam assembly.

Another object of the invention is to enable the relative settings of a number of rotary cams mounted upon one and the same shaft to be varied at will so as to vary the sequence in which a corresponding number of devices associated with and adapted to be operated by rotation of the shaft, are actually operated.

Still another object of the invention is to provide an electric cam-actuated switch which includes an assembly of rotary and relatively adjustable cams and an assembly of an equal number of `switch units each associated with andadapted to be operated by a corresponding one of the said cams.

A still further object of the invention is to enable the lsequence of operations of a number of cam-operated switch units assembled into an electric switch to be varied as desired, in a simple, speedy and ecient manner.

Yet another object of the invention is to provide an electric switch, comprising an assembly of earn-operated switch units, which is capable of being assembled quickly, easily and accurately.

A still further object of the invention is to provide a switch, comprising ankassembly of cam-operated swtich units, which is of compact, robust and economic construction.

The above and other more or less important objects of the invention will be apparent from the following description of a typical but non-limiting embodiment of the invention, when read in conjunction with the accompanying drawings.

-In the said drawings: Y

FIGURE l is an elevation of a multi-unit switch, the cover being shown in section.

FIGURE 2 is an elevation on a larger scale and partly in section, of a portion of the switch-actuating cam mechanism.

FIGURE 3 is an end elevation ofthe switch, the cover again being shown in section, and

FIGURE 4 is a section, along the line a-a, iFIG- URE l.

The switch shown in the drawings comprises a rectangular base plate 1 having metal or equivalent mounting straps 2 on its underside and an ebonite or other di-electric lining 3 on its upper side. A pair of parallel pillars 4 project respectively from and perpendicularl-y to, two opposite ends of the base and the upper edge of each pillar is formed with a semi-circular recess in which one ,of the bearings 5 of a camshaft 6 is seated; the said bear- 3,lilll,29i Patented Sept. 17, 1963 ice screws, also have semi-circular recesses wherein the bearings seat, and are provided with ports 8 to which'the switch cover 9 is fastened by bolts 10. The camshaft is, therefore, rotatable about its axis in the pillars and is mounted parallel to lthe base in a readily removable manner.

Six carn assemblies 11 are mounted upon the camshaft between the pillars, and an equal number of switch units 12 is mounted upon a spindle 13 carried by and between the pillars below and parallel to the camshaft; although six cam assemblies and switch units are shown, it is to be understood that, by increasing or decreasing the distance between the pillars and the length of the shaft, this number `may be increased or decreased as desired. A terminal bar 14 (see FIGURES 3 and 4) secured upon and between the pillars enables each of the said switch units to be connected through ilexible conductors such as 15, 16 and the terminals on the said bar, to a source of elect-ric current supply and a corresponding electrical appliance of which the operation is to be controlled by the said unit.

As shown mos-t clearly in FIGURE 2, each cam assembly consists of a bush 17, a ring 1S, a sleeve 19, a coil spring 2t) and two

annular cam plates

21, 22. The several assemblies are clamped end-to-end between two retaining collars of which the collar 23 is secured upon and around the shaft in abutment with one of the pillars, by a taper or other pin 25 whereas the 'second retaining collar 24 is likewise secured upon and around the said shaft in abutment with the other pillar, by a grub screw 26 which bites against the bottom of a keyway 27 formed in and lengthwise of the shaft. The bush, ring and sleeve are sliding fits around the camshaft, but the bush is held against rotation relatively to the said shaft by a -key 28 which engages and may be slidable along the keyway. The ring and sleeve are located upon opposite sides of the bush and their external diameters are re-spectively greater and less than the external diameter of the bush so that the peripheral zone of the ring projects beyond the y the bush whilst enabling them to be displaced manually and axially of the assembly relatively to the said bush so that they may be removed from the latter as and when desired, a system of transverse teeth or serrations which are pitched equidistantly apart, is formed around the external periphery of the bush, a complementary system of teeth or serrations is formed around the internal periphery of each plate, and the internal diameter of the said plates is such that the plates are free sliding fits around the bush and their teeth or serrations mesh with the teeth or serrations of the said bush. Further, each cam plate is of a thickness equal to half the thickness of the bush, the plate 21 is urged resiliently against the projecting flange of the ring by the plate Z1 which, in turn, is urged resiliently against the plate 22 by the spring 2) of which one end coil seats upon the said plate 21 whereas the opposite end coil seats either upon the ring of a next adjacent cam assembly or, in the case of the assembly adjacent the retaining collar 24, against an auxiliary ring 18a which is urged against the said collar. It will be noted that, in the case of Ilthe cam assembly adjacent the retaining collar 23, the said collar replaces the ring 18 and the corresponding cam plate 22 is urged against the collar.

As is indicated clearly in FIGURES 3 and 4, a lobe 21a and 22a respectively is formed upon the periphery of each

cam plate

21, 22, the said lobes being of equal depth and each extends around approximately one hundred and eighty degrees of the corresponding plate.

Each of the switch units 12 (which may be of any known andrsuitable construction) comprises a casing 29 which, in the vicinity of one end thereof, is mounted f upon the spindle lf3. An actuating plunger 31 projects from the top of the casing between the ends of the latter,

, relationship to the spindle, and aA diametrically pierced trunnion S6 journalled between the projecting strap ends has a threaded screw or stud 37 extending freely through its piercing. The lower end of the s-t-ud is formed with a domed head 38 which is anchored to and in rolling contact with a catch bar 39 by a screw fill, whereas the upper end of the stud, which projects beyond the trunnion, is engaged by a nut 41 retained in abutmentwith the said trunnicn byl a compressed coil spring d2. k Spacing sleeves 3@ mounted around the opposite ends of the spindle locate t-he switch units in side-by-side abutment and in alignment with their corresponding pairs o f lobed cam plates. Y

The catch bar 3g extends transversely of the switch, the studs of all the switch units are .anchored thereto, and its opposite ends are coupled respectively to the pil- Further, the sequence in which the several :switch units are operated may be Varied as desired by adjustment of the relative settings of theseveral pairs of cam plates and of the angular relationship between the lobes of the several pairs of cam plates,-such variation being effected manually'by disengagement of any one or more of they y. said pairs from its or their bush or bushes, and after silars 4 by tension springs 43 which are anchored to the said pillars by attaching them to pins la located above .the level of jaws 44 formed in and opening to convex edges of switch plates 45 fixed to the said pillars and projecting from the latter in the same direction as the casing straps 35 soV that, as shown in FIGURE 4, the catch Vbar is adapted to be held res-iliently in engagement with the jaws to locate the :several casings in positions wherein each of theV rollers 34 is urged into rolling contact with the lobed peripheries (of the

cam plates

21, 22 of a corresponding one of the cam assemblies 11.

t The cam shaft extends to the exterior of the casingl and any convenient means (not shown) for rotating the said shaft about its axis is assembled thereon externally of the cover. As the shaft rotates, the bushes 17 and cam plates 2l, 22 are rotated therewith, -with the result sponding switch unit so as to reciprocate the plunger 31 to actuate the said unit and thereby make and break one or more electric circuits of the corresponding switchycontrolled appliance.

The angular rotary movements that need be imparted to each pair of cam plates to depress and then permit the rising of the corresponding roller, are determined by the effective length of the lobes of the corresponding pair of cam plates and sinceeach lobe extends around approximately one hund-red and eighty degrees of its plate, the.

said effective length may be adjusted so that it spans any angle between one hundred and eighty and threehundred and sixty degrees, by relativeV rotation of the pair of plates. This adjustment is effected by :manual displacernent of the plate 22 and/or plate 21 axially of the cam assembly and against the action of the spring 20' so as to disengage the plate from its supporting bush 17 (see left hand `side of FIGURE 2) rotating the plate about the sleeve 19 so as to increase or decrease the degree of overlap of the lobes 21a, 22a and re-engaging the said plate with the bush, the re-engagement being facilitated by the concentricrelationship of the bush and sleeve and by the fact that :the external diameterV of Vthe sleeve is substantially equalrto the diameter of a circle passing through 'the roots of the teeth or serrations of the bush.

multaneous manual rotation of the disengaged pair Y through any desired angle relatively to the corresponding cam assembly, re-engaging same with the bush.

Such adjustment of the effective lobe length and/or Variation of the sequence of operations of the Several switch units, is or are facilitated by manually disengaging the catch bar 39 from the jaws of the catch plate 45. As the bar is disengaged from the jaws, the' tension springs 43 are elongated; therefore,V since the spring anchorages to the pillars are located ata higher level than the said jaws, the elongated springs drive the bar upwardly along the convex edges of the catch plates 45 lwith the result that the bar 39,V acting through the studs '37, trunnions 36 and straps 35, 4swing all the switch units upwardly about the. axis of the spindle 13,.,and the rollers are lowered out of contactwith their respective pairsY of cam plates.

Obviously, the relative settings of` the pairs ofcam'- plates may be varied `only in steps equal to the pitchrof the teeth or serrations of the bushes and cam plates.

Thus, if, for example, each bush and plate is provided with thirty-six teeth'or serrations pitched at ten degrees apart, the setting of each pair of discs may be varied by ten degrees or a multiple of ten degrees. However, smaller or microvariation of the setting of any one pair of cam plates may be effected, within line limits, by rotation of the corresponding nut 41 Vabout its threaded. stud 37 so as to increase or decrease, as desired, the distance between the corresponding trunnion and the catch bar, and thereby swing the trunnion supporting straps and "switch casing about the spindle 13y to effectV slight relative movement within correspondingly finer limits, between the contacting peripheries of the associated roller and cam plates. Consequently, any predetermined relative angular settings of the several pairsk of cam plates may be obtained approximately by disengaging, rotating and re-engaging the plate pairs with their respective bushes, subsequent rotation of the corresponding nuts enabling the settings to be obtained accurately. f

The construction of the cam assemblies, pillars and switch units, kand the methods of mounting same in the switch, also simplifies and minimises the costs of production, andfalso permits ready and speedy removal of any switch component for servicing or replacement should theneed arise. These advantages are obtained because the cam. assemblies and lswitch'units may be mounted upon the cam shaft and spindle respectively beforethe said shaft and spindle are assembledjrto the pillars. Thus the cam assemblies are mounted on the cam shaft by pinning `the

collar

2,3 upon the shaft and then sliding, in succession and from the opposite end of the shaft, on to and along the said shaft, the bush, sleeve, cam plates and spring of the rst assembly, then the ring, bush, sleeve, cam plates and spring of each additional assembly, the whole being located in position by fixing the collar 24 to the shaft whereupon, after passing the bearings 5` on to the opposite shaft ends and seating the said bearings in the pillar recesses, the complete assembly is clamped in position by securing. the recessed head pieces upon the pillars. Similarly,V by threading spacing sleeves 30a and straps 35 supporting trunnions 36 one after the other on to the spindle, connecting the threaded studs 37 to the catch bar 39, passing the said studs through the trunnion piercings, screwing the nuts 41 onto theV said studs and applying the catch plates 45 to the spindle 13, a second assembly capable of being connected to and between the pillars, is obtained. .l

iFrom the foregoing description, it will be apparent toy those skilled in the art that I have devised a novel, ellicient and simple rotary cam assembly which when assembled in an electric switch comprising an assembly of switch units, provides an efficient and robust switch of compact dimensions and permits the sequence of operations of the said switch units to be varied, as may be desired, in a simple, eicient and speedy manner. Whilst the specication describes, and the drawings illustrate, a typical and practical embodiment of my invention, it is to be understood that various alterations and modifications may be made without departing from the scope of the invention as dened in the following claim.

I claim:

An electric switch comprising a number of switch units each having an operating member, a rotary cam assembly including a shaft, a plurality of externallytoothed bushes mounted around in spaced apart relationship lengthwise of the shaft and rotatable with said shaft, at least two annular and internally-toothed cam plates mounted around and meshing with each bush, resilient means maintaining the cam plates on each bush in face to face abutment and against movement axially of the shaft, each of said cam plates being removable from their respective bushes by an axial sliding movement against said resilient means so as to permit the angular setting of any of the cam plates which are adjustable in predetermined increments corresponding to the pitch of the teeth, the peripheries of the cam plates meshing with each bush making rolling contact -with the operating member of one of said switch units, said switch units being pivotally mounted at one end upon a spindle which is parallel to the shaft, an anchorage plate extending parallel to the spindle, the other end of each switch unit being connected to said anchorage plate by a coupling whose efective length is manually adjustable so as to turn the unit about the spindle toward and away from the cam plates, a pair of catch plates, and tension spring means retaining said anchorage plate in engagement with said catch plates and also tending to drive the anchorage plate towards the cam assembly so that, when disengaged manually from the catch plates, the anchorage plate is spring driven to turn the switch units about the spindle in the direction which removes each operating member out of contact with the corresponding cam plates.

References Cited in the tile of this patent UNITED STATES PATENTS 1,848,349 Ieerson Mar. 8, 1932 2,153,865 Gersch Apr. 11, 1939 2,308,963 Davis Jan. 19, 1943 2,418,757 Collins Apr. 8, 19147 2,711,450 Carr June 21, 1955 2,848,588 Hackman Jan. 28, 1958 FOREIGN PATENTS 808,001 Great Britain Jan. 28, 1959