US1933760A - Brush lifting device - Google Patents

Description

c. RHNGWALD 1,933,760

BRUSH LIFTING DEVICE Filed Dec. l5. 1930 2 Sheets-Sheet l Novn "if, 1937.

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Patented Nov. 7, 1933 f UNI-TED STATES BRUSH LIFTING DEVICE` Clarence Ringwald, Springfield, Ohio, assigner to Robbins & Myers, Inc., Springeldhio, acorporation of Ohio Application December 15, 1930 Serial No. 502,339

2o claims. (011724-279) f My invention relates to` electric motors of the brush lifting type and a novel brush lifting mechanism therefor.

Brush lifting'and shortcircuiting mechanisms y for motors starting as. repulsion motors and thereafter operating as induction motors are known. The brush lifting mechanism of my invention is disposedl wholly at the ccmmutator end of the motor and hence rods, or other oper# ating devices extending through the armaturel lare not required. Y

In accordance With my invention the brush lifting and short circuiting mechanism is a comtherebysupported and guided.

Such position. as will secure? rotation in either direction. A mechanism of thispclass requires a non-rotating guide for holding the brush carrier in proper position relativetothe commutator `during-starting and to guide it back out of the way when the brushes are lifted andthe `short circuiting mechanism operated.

` According to my invention the guiding `mechanism `comprises a plate adjustably secured to the end frame of the motor, Withtwo pins extending parallel to the axis of the shaft and extending into sleevesforming a part of the brush carrier frame, which brush carrier frame 'is Il dispose the centrifugal mechanism directly` uponrthe shaft and radially inside the guiding pins.

The centrifugal mechanism comprises a pair of Weights adapted to be thrown out by centrifugal force against the tension of-a pair'of springs upon the attainment of. a predetermined speed which'is considerably higher than the speed at whichv the weights will again be re-Y tracted.

The `brushes are applied to the commutator through the action of the springs `which govern the centrifugal Weights. Theentire brush frame and brushes have no bias, i. e., nojspring loading of their own and hence-'there is required no end bearing under constant Wear.

The frame of the centrifugal mechanism is a generally rectangular stamping which is light and inexpensive. Likewise, the centrifugal Weights and arms are simple-stampings. The springs are iight coil springs placed in tension. These springs are light and strong and readily replaceable. The entire mechanism is unusually compact,l inexpensive and highly effective. It isreadily accessible for inspection. Y

Now in order to acquaint those skilled 'inthe art with the manner of constructing and operat- `9 of the laminations 1. These concentric cylin- 'J described hereinafter.

ing any excess lubricant tothe pocket 20 through ing a device embodying my invention'I shall describe, in connection With the accompanying drawings, a specific embodiment of the same.

In the drawings:` n y Figure 1 is a side elevation, partly in section, of a motor embodying my invention;

Figure 2 is a fragmentary section taken on the line 2-2of Figure 3, through thevbrush lifting device and commutator;

Figure 3k is a cross sectional view taken onthe line 3-3 of Figure 2;

Figure 4 is a side elevational View; of the inertia or centrifugal mechanism; 5

Figure 5 is an end view of the same, taken from the right of Figure 4; and i 77,0

4Figure 6 is a fragmentary view, illustratingY the connection.l of the spring to theinertia lever. Referring first to Figure 1, the motor herein showncomprises the eld laminaticns 1 and armature laminations 2, of known form, these'75` parts in an A. C. motor being generally termed stator and rotor, respectively. The stator laminations are conned between a flange 3, formed on one end of the cylindrical tubing shell 4 and a filler sleeve 5, which is held in place by anging the opposite end of the sleeve 4, asindicated at 6. The opposite ends of the sleeve 4 are finishedof as indicated at 7 8, to provide surfaces which are concentric wtih the inner face drical surfaces 7 and 8 are adapted to receive the rims oiflanges 10 and 12 Yof the end frames or housings 13 and 14. Theseend frames 13a-,.14 support bearings 15 and 16, having suitable bushings 17 and 18 of anti-friction metal'cooperating with round cylindrical bearing portions of the motor shaft 19. 4The bearing boxes15 and 16 embody suitable oil pockets such as that shown -at20 at the left of Figure 1. Oiler rings 22 dip` into the lubricant in the pocket 20 vand ride upon the bearing portion such as 23 through a slot in the anti-friction sleeve 17, as indicated at 24. The outer end of the journal boxjs .closedby a metal cap 25 pressed in place toexclude dust and to assist in draining the` lubri- 00. cating medium back to the pocket20 as through the passageway 26. Atv the opposite end ofthe journal box v15 a similari-flanged pressed yring 27, which isadapted to retain a feltwasher, if soV desired, prevents the entry of dust into the bear# ing vfrom the inner end andthe felt Washer (not shown) fits closely about the collar 28 `yvhich:,is mounted upon the shaft as will be more l-fully It also assists in returnof the commutator supporting frame 47.

the extremeouter ends of the p'ns'Q-areriveted `overas indicatedat 86 so that the saidguide pins 79 are rigidly connected tothe --plate 36.

The offset ears 84'prevent the riveted ends 86 from engaging the end plate 35. .Bolts, pro.- vided ,with suitable exterior fclamping nuts 89 lextend throughfthe slots l82--82 and serve to clamp the main atbody portion of the-platef36 against theend plate 35. Suitable indicia, for example, notches r90-90 are marked upon the `plate .36, these-notches being adapted to register with cooperating-marks on the plate 35. v i

The-slots 82`82 areV so arranged `that the rocker plate 36 may be shifted to sufficient angles to cause lthe motor to start v'invone direction or the other, as desired; f

The shifter sleeve 67 is` adapted to be shifted -from the position shown in Figures 1 !and'2 when the Apartsare at rest, towards the right when themotor isbrought to substantiallysynchronous speed, throughthe operation of asuitable centrifugal mechanism 92 which is shown lmore in detail in Figures 4, 5 and 6. The sleeve -either round in section oroblong in section,

having the ends of the vcoils substantially'paral- Y portions 95-95 of relatively limited area `but of considerable resiliency, whereby they are adapted to bridge the insulating plate 60 which liesbetween the commutator bars and the body At itsy oppositeend the shifter sleeve 67 is 'provided ,with a pair of parallel transverse .grooves -96-96 for receiving the shifter pins 97 which lie parallel to earch other onopposite sides of the shaft 19.y Y

The inertia, or `centrifugal mechanism is adapted to swing the pins 97 .aboutthe pin- ;left, as viewed in Figures 1 and 2.

1 brushi holder frame.

tles or pivots 98 to shift the sleeve 67 to the The connection between the shifter sleeve and the brush holder frame'is provided by forming ashoulder 99 upon the left handend ofthe sleeve adjacent the slots 96-96 and a groove 100 into which there is adapted to be seated a snap spring ring `102, of l Wire or: the like.' A thin steel washer 103, relatively closely embraces :the sleeve67 and is retained ybythe snap, orspring ring'102. A washer 104 Vof bakelizedffabrcor bakelizedbre-or the like is interposed between the steel `washer 103 and the hub 66 .of'the This .washer 104. fitsirelatively closely yon the lcylindricalY .part of lthe sleeve 67. A ring 105 `of similar insulationembraces the sleeve-67 and lies #within the-hub 66. Upon the opposite side of the hub fromthering 104 a washer of similar insulation 106 embraces thesleeve 105. A steel washer-107 backs, the in 'sulating washer 106 and' is'- interposed between the said insulating washer 106r` and, the shoulder 99. If desired, a" thin steel *washer 108 l'may' be interposed :between thel insulating washer .104

V:and the hub 66 to `,reduce wear.

pThe-hub 66 iis, by means of these washers and thesleeve 105, insulated .from the, shifter Vssleevell.` I I rshifts the sleeve .87 .and 'thereby thebrushes p63 .andthe short circuiting ring. 62, is shown more 1in detail in-Figures. 4, 5 and 6.

mechanism comprises the .collar li281" which is;flxerl` uponpthe reduced portion :23 of the shaft 19. as xbyfmeans of .fa pair of set. screws l09-arrangedzat suitable .parts of the periphery 'of the collar, for example, at 90 to eachother.

This icollar supports. a transverse` sheet metal.

plate .1.10 `which is secured .to the said, ycollar by riveting, :welding'or the like AIn the `form .shown the collar :28is-provided with are'duced -neck1112having a shoulder at one side and having `the .neck riveted over aty the` opposite.

side .so asitogrip the plate llfrmly.,

'The plate 110"is generally rectangular in outjj,l 80 The inertia, .or .centrifugal/mechanism Which .line :but yit has the margins at opposite sidesv l bent up at right anglesv to the body ofthe plate asshowny at 113 in Figures 4 and "5to provide flanges, `whichfianges arecut out. to providethe pivot ears 11'4,four in number,at each en dfof the flange 113. Between each ypair rof ears formed on .the vflange 113 there .is .provided *a guard or retaining ear 1-15 whichV is curved aroundthe central part of the corresponding f tension spring 116 to prevent the central part of such spring from ilyingout radially under centrifugal stress. I The lshiftingpins 97-97 are riveted,V or otherwise fixed-at their opposite ends in companion levers '.117 which are formed as U-shaped stampings, the joining bar, or bottom ofthe U by .which pairs of levers 117 are integrally joined, being lplainly shown in elevation 'in1,15v

rFigure .5. If it is desired' to increase the weight of the bar ll8.an additional 'flat bar such as that lshown at 119 in Figure`2" may be riveted to the bar 118.

The levers 117 are in effect bell ycrank levers comprising the shifter arm 120 and the inertia .arm.122, theinertia arrnl in each ycase having the bar 118 joined thereto. The pivot or fulcrumI on .the pin 98 is disposed radially beyond the arms 120 `and 122 and it may be seen, therefore, that the,

inertia weight 118 is leastY effective before thebell crank levers swing about their pivots 98 andare of substantiallymaximum effectiveness after'the inertia weightshavecaused the levers to move and to shift theshifter sleeve 67 Ato the right asjo` lindrical vbody of-the ring 123 bears edgewiseagainst the plate 110 radially 'beyond the riveted .neck*112. jBy means of vthe buffer ring'123'a suitable stop for the shiftersleeve 67 is provided andalso the collar 28 is accurately spaced with respect to the'shoulder 93 on the shaft 19. Afelt'.

washer.; 125 .is preferably. interposed between the .bufferr'ring'123 .and the endof the shifting .sleeve 67. Preferably an: anti-friction lwasherof bakelized Lfebr-ic or the like islocatedv at 126- between theendVV of the-)collar 29and the be'aringl bushing to `the right as viewed in Figures 1 and 2.

17. Likewise, one or more lwashers may be interposed at 127 between the shoulder 129 atthe opposite end of shaft 19 and the bearing bushing .18 of the bearing box 16. a

The bell crank levers 117, which arelshownin -elevation in Figure 1 are providedv with short "arms 129 lying, when the parts are in the posi- Y i tion shown in Figures 1 and 2,'radially. 'beyond ends of the said pins 130 are provided with cir- I cumferential grooves `and the springs 116 are provided with eyes which hook over the ends Tof the pins 130` and rest in the said grooves. The pins 130 are nurledy or scored and pressedinto the arms 129 so thatthey are thereby retained against Vmovement by the locking action ofthe nuris132 with'the bore of `the opening through the corresponding arm 129.`

The operation of the brush shifting and short oircuiting mechanism is as follows: With the parts as shown in Figurel or 2 the springs 116 bring the pins 13,0 inwardly until they engage the pivot ears 114. This holds the inertia weight `such as 118 in their innermost position. The

shifter arms 120` of the bell crank levers 117 have, through their connected shifter pins 97 and the slot 96, shifted the sleeve 67 to substantially the limit of movement inwardlyV or At this time the short circuiting band 62 is housed entirely within the commutator frame away from the commutator segments. At the same time the brush holder frameis carried towards the Acornrnutator so that the brushes 63 engage the radial'face ofthe commutator. The springs 116, operatingl through the leverage system, apply suflcient pressure to the brush holder frames to overcome the relatively `light tension of the brush follower springs "l2,` so that the brushes 63 are applied underwa' light, but sufficient `spring pressure against the radial'face's of the commutator bars.

If now the stator 1 is energized by connecting to a source of suitable single phase current, the leads for which maybe led to the stator windings through the insulating sleeve 133, therotor windings are energized. The present motor is provided with two pairs of poles and the brushes are arranged to selectively short circuit the coils of the rotor through the commutator to cause the motor to start up as a repulsion type motor.` As is well known, sufficient torque may be developed to start under fairly heavy load.

sleeve 67 is quickly thrown, or snapped to the collar 28 has upon Vthe reduced portion 23` of the shaft 19, this being secured, primarily, by the setl screws 109. The grooves-96in which `rosarino the shifting pins 97 are arranged to play, are straight cross grooves and hence any tendency to cause rotation between the shifter sleeve 67 .andthe shaft 19 will be unable to effect the same, since the grooves96 do not extend completely around Ythe shifter sleeve 67. Also, the friction ,between the short circuiting band 62, the groove 94 onthc one hand and the recess 50 on the other, tends to prevent such rotation.

j The brush holder frame 61 is held against rotation by the guiding pins 79 which are fixed on the rocker plate 36.

As the shifter levers operate to carry the shifter sleeve 67 to the left, the shifter sleeve first carries the short-circuiting band across the plate of insulation into engagement with the commutator segments 55, short circuiting the windings of the rotor 2 and causing the mo torto continue to operate as an induction motor, and thereafter the brushes 63 are lifted or moved out of engagement withthe commutator. This movement of the short circuiting band to `short circuiting position first is accomplished by positioning of the short circuiting band for movement with the initial movement of the shifter sleeve 67 whereas the follower levers 70 tendto maintain the brushes 63 in engagement with the commutator at least momentarily or during the initial movement of the sleeve 67. The distance which the spring actuated brush follower levers 70 can follow the brushes is limited by the engagement of said levers 70 with the sides ofthe brush holder sockets, so that the brusheswill be removed from engagement with the commutator segments and at the same time wear `between thev brushes and commutator is reduced.

It will be observed that the brush holder frame `will assume a position on the guiding pins 79 where minimum friction with respect to the moving sleeve 67 occurs.

Since the guarding ears 115 are located at the central parts of the 'springs they do not interfere with theeifective and equal operation of the two ends of the springs.

In Figure 2 I have shown a modified form of commutator. -In this construction the commutator bars are recessed at their backs to receive lan insulating ring 135. This ring has a series of counterboredholes for receiving mounting rivets. Thefdo'ublevended rivets 136 have collars at their central portion and one end of the rivet, in each" case, is first spun or riveted lthrough the holein the ring 135 and then the commutator bars are mounted on said ring in spaced relationandheld thereto as by means of the riveted pins 137. The insulating plate 66 is thenlaid upon the back of Ythe ring 135 `and the cylindrical inner edges of the commutator bars and the inner ends of the rivets 136 are spun or riveted tothe flange 48 of the commutator body or frame 47. .i

VThis construction is optional. The specic form` of the commutator is lnot involved in the present invention so long as it conforms to the requirements of the brush lifting and short ciry cuiting mechanism heretofore described. n

I do not intend to be limited to the details shown and described, except as they are recited in the appended claims.

I claim:

1. In a mechanism of the class described, the combination with a motor shaft and end frame of a plate mounted on the end frame and adapted for angular adjustment relative thereto, guiding pins mounted on the plate, a brush holder frame sleeved on said pins for free end wise movement-on said pins, a sleeve endwise shiftable on the shaft, a frame xed cn the shaft, shifter levers pivoted on said latter frame and having operatinor arms coupled to said sleeve and inertia arms and tensionsprings lying on opposite sides of the shaft connecting said levers to hold the inertia arms inwardly when the shaft is at rest, said sleeve and said gorush holder frame being coupled together for endwise motion but being rotatable relative to each other.

2. In combination, a shaft, a motor frame member, a centrifugal mechanism comprising levers having inertia arms mounted on the shaft, a shifting sleeve on the shaft coupled to said levers,k a brush frame mounted on the sleeve for endwise motion therewith but free for relative rotation therebetween, and a non-rotatable guide disposed radially outside the centrifugal mechanism,` said brush frame being slidably guided on said guide and brush means carried by said brush frame and movable into and out of engagement with the commutator.

3. A guide frame for centrifugally operated brush holder frames comprising a plate having a central opening adapted to embrace a guiding hub and having an arcuate slot concentric with said opening, offset portions disposed about the marginscf the plate and having openings therethrough, and shouldered pins riveted in said openings, Asaid pins extending parallel to the axis of said central opening and attached directly to said plate.`

e. In combination, a motor end frame having a bearing providing a hub and having a fiat f j end wall, a guide frame comprising a hat plate having a central opening piloted on said hub, an arcuate slot adjacent kthe lmargin of the plate, a clamping bolt passing through said slot and through said flat end wall, a plurality of oilset earson the margin of the vplate and guide pins secured to said ears and extending parallel to the axis of said central opening, said guide pins being carried by said plate independently of the end wall of the motor frame and independently of said clamping bolt.

5. In combination, a motor end frame having a bearing providing a hub and having a flat end wall, a guide frame comprising a 'fiat plate having a central opening piloted on'said hub, an arcuate slot adjacent the margin of the plate, a clampirnT bolt passing through said slot-and through said flat end Wall, a plurality of offset ears on the margin of the plate, guide pins secured to said ears and extending parallel to v the axis of said central opening, a brush holdarcuate slot adjacent the margin of the plate, a clamping bolt passing through saidv slot and through said flat end Wall, a plurality of offset ears on the margin of the plate, guide pins secured to saidears and extending parallel to the axis of said central opening, a brushholder frame sleeved on said pins and free to move en wise thereupon, and brushes carried by said holder, the slot permitting sufiicient rocking adiustment to locate the brushes so as to produce rotation of the cooperating armature in either direction, there being sleeves of insulation fiiredly mounted in said brush holder frame and freely slidable on said pins, and inertia Weight mechanism adapted to operate the brush holder frame out insulated therefrom.

'l'. In combination in a motor, a frame having end plates providing bearings,l one of ksaid bearings providing a piloting hub, a shaft mounted in the bearings, a commutator on the shaft comprising a base having a hub which is secured on the shaft, said base having a concenv tric cylindrical recess, metallic segments mounted in insulated relation on the base, said segments having radial faces adapted to be engaged by brushes and having a cylindrical inner face substantially registering with the surface of the recess, a rocker plate having an opening piloted on said piloting hub and adjustably clamped to the adjacent end plate, guiding rods mounted atene end on said rocker plate and extending parallel to the axis of the shaft,'a brush holder frame sleeved on said rods, brushes for cooperation withy the vradial faces of the commutator segments carried by said latter frame, a shifter sleeve slidably mounted on said shaft Vand having one end extended into said cylindrical recess, said end of the sleeve having a groove, a spring band mounted in said groove and adapted when the sleeve is shifted to be brought into Contact with the cylindrical faces of saidsegments to short circuit the same, a centrifugal mechanism carried on said shaft and confined radially within said guiding rods, said latter mechanism comprising levers carrying inertia weights and having operating connections With said shifter sleeve, said brush holder frame embracing said sleeve and there being shoulders on the sleeve on each. side of the shifter frame. Y

8. In combination, a shaft, a collar onthe shaft fixed thereto, a transverse plate mounted on said collar, said plate having pivot ears disposed in pairs on opposite sides. of the shaft, said ears being disposed at right angles to the body of the plate and pairs thereof having pivot holes in alignment with each other, bell crank levers formed of 'l1-shaped stampings having pivot holes disposed between pairs of ears, pivot pins extending through said aligned holes in the ears and in the bell cranks, the bottom of the U of each lever stamping providing an inertia Weight, both arms of each bell crank lever extending inwardly from the pivots in said ears, the free ends of the U-shaped stampings being joined by transverse pins, said bell crank levers naving arms disposed beyond said pivot openings, transverse pins extending between the arms, said pins at their ends extending out beyond the pivot ears, and a pair of tension springs connecting the outer ends of said last named pins, a sleeve on the shaft, said sleeve being grooved to receive the nrst named transverse pins.

9. In combination, a shaft, a collar on the shaft fixed thereto, a transverse plate mounted on said collar, said plate having pivot ears disposed in pairs on opposite sides of the shaft, said ears being disposed at right angles to the body of the plate and pairs thereof having pivot holes in alignment with each other, bell crank levers formed of U-shaped stampings having pivot holes disposed between pairs of ears, pivot pins extending through said aligned holes in the ears and in the bell cranks, the bottom of the U of each lever stamping providing an inertia weight, both arms of each bell crank lever extending inwardly from the pivots in said ears, the free ends of the U-shaped stampings being joined by transverse pins, said bell crank levers having arms disposed beyond said pivot openings, transverse pins extending between the arms, said pins at their ends extending out beyond the pivot ears, and a pair of tension springs connecting the outer ends of said last named pins, a sleeve on the shaft, said sleeve being grooved to receive the first named transverse pins and switching means carried by said last named sleeve.

10. In combination, a shaft, a collar on the shaft fixed thereto, a transverse plate mounted on said collar, said plate having pivot ears disposed in pairs on opposite sides of the shaft, said ears being disposed at right angles to the body of the plate and pairs thereof having pivot holes in alignment with each other, bell crank levers formed of U-shaped stampings having pivot holes disposed between pairs of cars, pivot pins extending through said yaligned holes in the ears and in the bell cranks, the bottom of the U of each lever stamping providing an inertia weight, both arms of each bell crank lever extending inwardly from the pivots in said cars, the free ends of the U-shaped stampings being joined by transverse pins, said bell crank levers having arms disposed beyond said pivot openings, transverse pins extending between the arms, said pins at their ends extending out beyond the pivot ears, and a pair Aof tension springs connecting the outer ends of said last named pins, a sleeve on the shaft, said sleeve being grooved to receive the first named transverse pins, said transverse plate having ears extending outside the central parts of said springs to restrain the springs from being extended radially by centrifugal force.

11. In combination, a shaft, a collar fixed on the shaft, a transverse generally rectangular plate fixed to the collar, a shifter sleeve mounted on the shaft, said plate having pivot ears bent up along two opposite margins, said ears being apertured, pivot pins extending through the apertures of the ears and lying parallel to each other on opposite sides of the shaft, four bell crank levers mounted cn said pivot pins inside said ears and comprising inertia arms and operating arms, said levers having their pivotal portions disposed radially outermost so that the arms extend diagonally inwardly generally toward the shaft, the operating arms of each pair being joined by a transverse shifter pin, the inertia arms of each pair being connected together by a transverse inertia member, said shifter sleeve being grooved to receive the shifter pins, said levers having outward extensions and spring anchor pins extending through said extensions and projecting across the edges of the ears and serving to limit the angular position of said levers, and tension springs connected to the ends of said latter pins for holding the inertia arms inwardly, and a brush holder frame guided longitudinally of the shaft and coupled to said shifter sleeve.

l2. In combination in a motor, a motor frame having end frames comprising bearings, a shaft extending through said bearings, one of said end frames having a flat internal clamping face and the bearing thereof having a piloting boss, a rocker guide plate having an opening piloted on said boss, and having an arcuate slot for angular adjustment about said boss, clamping means extending through said slot for clamping the guide plate against the clamping face of said end frame, guide rods fixed to said rocker plate, a brush holder sleeved on said rods, said shaft having a shoulder adjacent said bearing of said one end frame, a collar on said shaft, a transverse pivot plate secured to the end of said collar remote from said one bearing, a hollow spacer disposed between the shoulder on the shaft and said pivot plate, said pivot plate having integral pivot ears extending in parallel planes on each side of the shaft, U- shaped stampings providing leaded bell crank levers at their ends extending in planes parallel to the pivot ears and the pivotal portions of connected bell crank levers, shifter pins connecting the free ends of the bell crank levers, shifter sleeve guided on the shaft and being grooved at opposite sides to receive the shifter pins, said pins preventing rotation between the sleeve and the shaft, coil springs lying outside the pivot ears and parallel thereto connecting the adjacent ends of said U-shaped stampings, said transverse piate having fingers extending around the outside of said springs along their central portions to prevent radially outward movement thereof due to centrifugal force.

13. In combination in a motor, a motor frame having end frames comprising bearings, a shaft extending through said bearings, one of said end frames having flat internal clamping face and the bearing thereof having a piloting boss, a rocker guide plate having an opening piloted on said boss and having an arcuate slot for angular adjustment about said boss, clamping means extending through said slot for clampthe guide plate against the clamping face of said end frame, guide rods fixed to said rocker plate, a brush holder sleeved on said rods, said shaft having a shoulder adjacent said bearing of said one end frame, a collar on said shaft, a transverse pivot plate secured to the end of said collar remote from said one bearing, a hollow spacer disposed between the shoulder on the shaft and said pivot plate, said pivot plate having integral pivot ears extending in parallel planes on each side of the shaft U-shaped stampings providing loaded bell crank levers at their ends extending in planes parallel to the pivot ears and the pivotal portions of connected bell crank levers, shifter pins connecting the free ends of the bell crank levers, a shifter sleeve guided on the shaft and being grooved at opposite sides to receive the shifter pins, said pins preventing rotation between the sleeve and the shaft, coil springs lying outside the pivot ears and parallel thereto connecting the adjacent ends of said U-shaped stampings, said transverse plate having fingers extending around the outside of said springs along their central portions to prevent radially outward movement thereof due to centrifugal force, a commutator having segments provided with a radial face and an internal cylindrical face, said shifter sleeve having a groove, and a coil spring of toroidal form disposed in said latter' groove and being adapted to engage the cylindrical surface of said segments when the Shiite sleeve is shifted by said shifter pins.

14. In combination in a motor, a motor frame having end frames comprising bearings, a shaft extending through said bearings, one of said end frames having a flat internal clamping face and the bearing thereof a piloting boss, a rocker guide plate having an opening 4piloted. on said boss and having an arcuate slot for angular' adjustment about said boss, clamping means extending through said slot for clamping the guide plate against the clamping face of said end frame, guide rods fixed to said rocker plate, a brush holder sleeved on said rods, said shaft having a shoulder adjacent said bearing of said oney end frame, a collar on said shaft, a transverse pivot plate secured to the end of said collar remote from said one bearing, a hollow spacer disposed between the shoulder on the shaft and said pivot plate, said pivot plate having integral pivot ears extending in springs lying outside the pivot ears and parallel thereto and connecting said U-shaped stamp-A ings, saidgtransverse plate having nii-gers extending around the outside of said springs along their central portions to prevent said springs being extendedby their own centrifugal force,

Va commutator having segments prov'ded with.

a radial face and an internalcylindrical face, said shifter sleeve having a groove, and a coil spring band disposed in said latter groove and being adapted to engage the cylindrical surfaces of said segments when the shifter sleeve is shifted by said shifter pins, said brush holder having a central hub portion provided with an aperture passing over said shifter sleeve, said shifter sleeve having a shoulder lying on one side of the hub portion of the brush holder and a groove upon the other side thereof, and a snap ring in the groove for holding the shifter sleeve and the brush holder together for endwise motion but permitting rotative motion.`

15. In Vcombination with a cominutator having segments provided with radial faces and internal cylindrical faces of a short circuiting means comprising a sleeve having a relatively wide shallow groove and a band shaped coil spring the median parts of the coils of which are offset toward each other, leaving enlarged portions at the end of each coil which are relatively `ireely expansible and conipressible radially oi the sleeve to make good short--circuiting contact with the cylindrical surface of said segments, a motor shaft, said sleeve having a second groove and centrifugal means including a shifting lever having a pin lying in a direction erally across the axis of the motor shaft and engaging in said second groove. l

16. In combination, a brush Supporting frame comprising a central hub portion having a cenn tral bore and integral brush holders having oblong bores therethrough parallel to the central bore, ears extending outwardly from said brush holders, brush follower levers pivoted between said ears, springs disposed about the pivots of said levers for urging the ends of the levers toward the sockets, mounting sleeves having bores the axes of which are parallel tothe axis of the central bore and upon opposite sides of the saine, said sleeves being attached to the hub by webs joining adjacent brush holders.

17. In combination, a brush supporting frame comprising an apertured hub portion and peripherally disposed brush holding sockets open at both ends, integral guiding sleeves on the hub portion, stationary guide rods extending through said sleeves and a shifter sleeve having shoulders on opposite sides or" the hub for shifting the brush supporting frame on said guide rods.

18. In combination, a rotatable shaft having a reduced portion and a main portion with a shoulder between them, a collar fixed upon the reduced portion, a transverse frame plate secured upon one end or" the collar, shifter levers having inertia arms, springs `for said levers, said levers being pivoted on said frame plate, a shifter sleeve slidable on the main portion of said shaft, shifter connecting `the levers and the sleeve, aV buner collar of a diameter greater than the diameter of the main portion of the shaft lying between the said shoulder and said frame plate and adapted to be engaged by the sleeve when the shifter levers are actuated by the inertia arms.

19. A centrifugal switching device comprising a rotatable shaft, a stationary guide parallel to the shaft, a frame non-rotatably guided along said guide, said frame carrying an electric contact, collar on the shaft, a transverse plate on said collar, said plate having pivot ears disposed in parallel planes upon opposite sides of the shaft, U-shaped stampings comprising each a transverse joining portion providing an inertia meinben'and bell crank levers disposed in parallel planes to said pivot ears, pivot pins in said pivot ears extending parallel to said transverse plate and passing through the said bell crank levers, said cell crank levers having inertia arms joined by lsaid inertia member and free arms having shifter pins, and a yshifter sleeve for shifting said frame, said sleeve being disposedcn said shaft and having grooves for. receiving said shifter pins.

20. A centrifugal switching device comprising a rotatable shaft, a transverse plate mounted nonrotatably on the shaft, said plate having integral pivot ears at its opposite margins disposed in parallel the shaft, a pair of Ushaped stampings each comprising a transverse joining portion providing an inertia member, and bell crank levers disposed in parallel planes adjacent the pivot ears, pivot pins extending through the ears and the levers, said pins lying substantially in a common plane parallel to said plate, said levers having inertia arms joined by said inertia memand :free shifter arms provided with shifter pins, a shifter sleeve on the shaft, said sleeve being grooved to receive said pins,V and electric switching means actuated by shifting of said shifter sleeve.

CLARENCE RINGWALD.

lanes upon opposite sides of Y

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