US1680795A - Brush-lifting device for electric motors - Google Patents

Description

Aug. 14, 1928.

G. H. LELAND BRUSH LIFTING DEVICE FOR ELECTRIC MOTORS Filed March 18', 1926 5 Sheets-Sheet 5 Sheets-Sheet 2 Q m Qmwm N 3 GEORGE H. LELAND.

Aug. 14, 1928.

G. H. LELAND BRUSH LIFTING DEVICE FOR ELECTRIC MOTORS Filed March 18, 1926 G. H. LELAND BRUSH LIFTING DEVICE FOR ELECTRIC MOTORS Filed March 18, 1926 5 sheets-sheet 5 GEORGE H LELAND Patented Aug. 14, 1928.

UNITEDuSTATES PATENT OFFICE.

GEORGE H. ELAND, on DAYTON, OHIO, AssIeNoR or O E-HALF To THE LELA D v ELECTRIC COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

BRUSH-LIFTING DEVICE FOR ELECTRIC MOTORS;

' Application filed March 18, 1926. Serial No. 95,579.

One object of the invention is to provide a device which willbe automatically moved into engagement with the'brush to hold the same out of contact with the commutator.

A further object of the invention is to provide a device which will be automatically operated to engage the brush, move the same out of contact with the commutator, and hold the same in its inoperative position.

A further ob ect of the invention 18 to provide an automatically actuated device having frictional contact with the brush to hold the same against movement toward the commutator.

A further object of the invention is to provide a repulsion-induction motor with a centrifugally controlled short CiICHltlIlE', device and a centrifugally controlled device for holding the brush in an inoperative position and having means for causing the two centrifugally controlled devices to operate in unison. i i

A further object of the invention is to providesuch a mechanism in which a single yieidable device will act upon bothcentrifugally operated mechanisms.

Other objects of the invention will appear as the mechanism is described in detail.

In the accompanying drawings Fig. 1 is a front cleva tion of a mechanism embodying my invention, partly in section, with the retaining plate removed, and showing the centrifugally operated mechanisms in their re tracted positions; Fig. 2, is a section taken on the line 22 of Fig. 1; Fig. 3 is a front elevation of the centrifugally operated mech anisms with the retaining plate removed andshowing said'mechanisms in their extended positions; Figmt is a section taken on the line 2,.2 of Fig. 1 and showingthe centrifugally operated mechanisms in their extended positions; Fig. 5 is a transverse sectional view taken on the line 5-5 of Fig. 4; Fig; 6 is a detail of one of the connecting plates; Fig. 7 is a sectional detail view of a modified form of brush controlling device; Fig. 8 is a sectional detail. view of another form of a brush lifting device; Fig. 9 is a sectional detail view of another form of brush con? trolling device; Fig. 10 is a sectional view taken axially of the commutator and show ing the brush controlling mechanism applied to the face ofthe commutator; and Fig. 11

is a sectional view showing a modified actuating mechanism. for .the brush lifting device. 1 v 5 In these drawings I have illustrated'one' embodiment of my invention, together with certain modifications thereofbut it willzbe understood that the. various formshere shown have been chosen for the purpose of V illustration only and that the .mechanism may take various forms and may be used 7 either in whole or in part with commutators of various kinds. 1 y

In these drawings I have shown only'the shaft and commutator of a motor, as :the other-parts of the motor have no direct hearng on the invention and are not'necessar'y to its understanding. The commutatormay be of any suitable character and; as here shown, at 1, is of a conventional type and is rigidly secured to the motor shaft 2. 1 The commutator comprises a circumferential series of contact bars 3 which are insulated one from the other and from the. body or core of the commutator. Arepulsion-im duction motor starts as a repulsion motor and operates as such until it has reachedits normal or working speed, at which timethe commutator is automatically short circuited and the motor continues to operate as an inductionmotor so long asxit maintains its normal speed. The short circuiting of the commutator is usually accomplished by means of a centrifugally operated short cir cuiting device and there are various forms of short circuiting devices which may be used for this purpose. As shown. in Figs.

1 to 4 the short circuiting device comprises moves into engagement with the contactbars 3 of the commutator when lthe short. circuits commutator bars.

ing device is moved outwardly by centrifugal force, the commutator bars being provided with overhanging end portions 6 to.

limit the outward movement of the short circuiting element. contact members 4 slope forwardly and inwardly and are preferably slightly curved to provide a seat for a circumferentially arranged contractile band 7, which is here shown in the form of an annular helical spring; This spring serves to retain the contact members normally in 'their'innermost or retracted positions but will yield to permit thecontact members to move outwardly by centrifugal force into engagement with the contact bars of the commutator when the'motor has'attained a'p'redetermined speed. Mounted on the motor shaft 2, adjacent to the forward edges of the contact members of the short circuiting element, is a plate or disk 8, the outer portion of which-extends beyond the outer edges of the contact members and against which the helical spring 7 bears, the arrangement being such that the spring will resist the outward movement of the contact members and will also press the parts 5 thereof against the. face of the commutator. If desired, this plate 8 may be provided with an obstructiomsuch as an annular bead or rib 9, so arranged that it will engage the outer side of the annular spring 7 when the short circuiting element is in itsretracted position and will resist the outward movement of said spring, and consequently of the contact members, until the centrifugal force is sufficient to force the spring past the bead or obstruction 9. 'When the short circuiting element is in its extended or operative position the bead 9 will engage the inner side of the spring 7 and thus resist its inward movement until the centrifugal force has been so reduced that the tension of the spring will move past the bead. Thus the outward movement of the short circuiting element maybe prevented until the motor has attained a relatively high speed and when this speed is attained the spring will be moved quickly across the bead 9 and the several contact memberswill move quickly and simultaneously into engagementwith the Likewise the bead will resist the inward movement of the spring until the speed of the motor has been reduced considerably below the speed which was necessary tomove the short cireuiting elementinto its-operative position; Consequently minorfluctations of speed 'willinot cause the short circuiting deviceto move to its inoperative position. As here shown, the several contact members are retained in sub-, stantially radialpositions and held against lateral displacement by meansof connecting plates 10 which arearranged between adjacent-contact members at intervals about the The outer edges of the short circuiting element and which are provided with forwardly extending portions or lugs 11 which are slidably mounted in a guide or slot 12 in the disk or plate 8. In

engagement therewith. If desired, the supporting portion 13 of the plate may have an outwardly extending projection or bead which extends into. correspondingly shaped recesses 16in the inner edges of the contact members and permits of a pivotal movement thereof.

Mounted on a fixed part of the motor frame, not here-shown, are the brush holders 17, their being in the present instance two of these brush holders spaced apart about the circumference of the commutator and electrically connected one to the other by a conductor bar 18. Each brush holder has a longitudinal guideway 19 extending lengthwise thereof and in which is mounted a brush :20, the brush being of a width slightly less than the width of the guideway. The central; portion ofthc guideway is enlarged to receive a coiled spring 21 which is confined between the upper end of the brush and a fixed abutment at the outer end of the guideway, and serves to move the brush toward the commutatorand to hold it yieldingly in engagement therewith. .As here shown, the outer end of the guideway is closed by a disk 22 held in position by a plug 28 screw threaded into the end of the brusn holder. The brush 20 is connected with the disk 17 by a flexible conductor 2d which-will permit of itsmovement lengthwise of the guideway. Supported adjacent to the brush holder and arrangedto enter the gui deway'19 is a device adapted to engage the'brush and hold .the same against movement toward the commutator. This device may be of such a character that it will both grip the brush and lift the same away from the commutator and hold it in spaced relationto the commutator, or it may be of such. a character that it will merely grip the brush and hold it against movement toward'the commutator, without imparting outward.movement thereto. In this latter case the contact-of the periphery of the comthe brushwill engage only the high point IOU llU

thereon, and the impact of this high point of the commutator with the brush will cause the brush to be moved further outward so that after a few rotations of the commuta tor the high point also will clear the brush. In that form ofv the device illustrated in Figs. 1 to 6 I have utilized a device which lifts the brush away from the commutator and holds the same in its lifted'position. As there shown thebrush holder 17 is provided in its front and rear walls .with openings in which are mounted clamping members or blocks 26 and 27, the clamping blocks being of such a character and so arranged that they may be moved into the side portions of the guideway 19 and will there engage the respective edges of the brush 209 Any suitable means may be employed for causing the operative movement 7 of the clamping members but preferably this is accomplished by applying pressure to one clamping memberv and pressing the brush against the other clamping member. the last mentioned clamping member being yieldably held against" 'movement. The clan'iping members are so mounted that when moved laterally in one direction they will also be moved outwardly away from the commutator. As here shown, each clamping member has an upwardly and rearwardly inclined slot 28 through which extends a pin 29, these pins being supported in the Walls of the brush holder. Pivotally mounted adjacent to the brush holder is a lever 30 which, as here shown, comprises parallel side members arranged on opposite sides of the brush holder. In the present instance, these side members or levers are pivotally supported by the rear pin 29. The two members of the lever extend forwardly beyond the brush holder and are rigidly connected one to the other by a transverse bar 31.. In the present construction, the. two arms of the lever are provided with openings 32 to receive the ends of the forward pin 29 which project beyond the respective sides of the brush holder, these openings beii'ig of such a size that the pin will not interfere with the movement of the lever. A spring acts on the rear clamping member 27 to move the same forwardly and to cause it to act upon the brush 20 to move the latter in a forward direction. This spring may be of any suitable character but, in the present device. it is shown in the form of a loop spring 33, the rear portions of which are curved downwardly and connected by a transverse bar 34 which is seated in a recess formed in a lug 36 projecting rearwardly from the clamping member 27. The forward ends of the two arms of the loop spring are seated in the respective arms of the lever 30, the arral'igement being such that the cross bar 34 of the spring will at all times exert a forward pressure on the clamping member 27. The forward clamping member 26 is so connected with the lever that the upward movement of the lever will move the clamping member rearwardly and into engagement with the brush. Preferably this connection is established by a link, as shown at 37, this link being provided at its rear end with a bearing portion 38t0 enter a slot 39 in a lug 40' extending forwardly from tlieclamping member 26. At its otherend the link is provided with trunnions ll which are seated in openings in the respective side members of the lever 30. The arrangement of the link is such that when the lever is in its lowermost position,

.as shown in Fig. 2, the link will extend downwardly and forwardly from its point 7 of connection with the clamping member. thus permitting that clamping member to move forwardly until its inner edge is substantially flush with the inner surface of the front wall of the guideway 19. The rear clamping member 27 which is pressed forwardly by the spring 83 will thus force the brush forwardly but will not engage the same with sullicient pressure to materially resist its movement toward the commutator by the spring 21, the forward movement of the length of the link 37,.itwill be obvious that the rear end ofthe link will be forced rearwardly and will carry the clamping member 26 with it. This movement of the clamping member will cause the same to engage the forward edge of the brush 2-0, force the brush toward the rear wall'of the brush holder and force the rear clan'iping member 27 rearwardly against the action of the spring 33. Consequently the brush 20 will be gripped between the two clamping members with a pressure which will be sufiicient. to prevent the inward movement of the brush by the spring 21. 7 It will be apparent that the two. clamping members will .both engage the brush before they have completed their rearward movement and conse quently as the rear ard movement of the clamping members is continued they will be elevated by the ac ion of the pins on the inciined slots 28, thereby lifting the brush and firmly holding the same in its lifted position. It will be noted that the arrangement of the lever. 30 and link 37 is such as to constitute a toggle and that the action of the spring 33 011 the lever will tend to move this toggle in either direction when it has been once moved past a central position.

Consequently after the lever has been positively moved outwardly far enough to carry the toggle across the center the remainder of the movement will be quickly accomplished by the spring, and likewise when the lever has been moved inwardly far enough to carry the toggle across center the inward movement will be quickly completed by the spring.

The automatic control of the brush controlling device may be accomplished in any suitable manner but preferably this operation is controlled by centrifugal force and 'downwardly and then rearwardly so as to provide a channel between the transverse bar 31 and the part 43, which channel opens rearwardly. Each of the weights 42 has at its outer edge a forwardly extending flange 44, the several flanges extending for the full width of the weights, so that when these weights are in their innermost or retracted positions the flanges 44 of the several weights will constitute a practically continuous circumferential flange, which flange extends into the channel formed between the parts 31 and 43 of the lever 30. It will be obvious therefore that when the centrifugal device moves outwardly from the position shown in Fig. 2 to that shown in Fig. 4 the flange will engage the outer wall of the channel and force the lever outwardly until the toggle has been moved across center. The action of the spring will then carry the lever outward afurther distance so as to move the outerwall of the channel away from the flange of the centrifugal device and thus cause both walls of the channel to be spaced from that flange and permitting the latter to run free in the channel without contacting with any part thereof. Likewise when the centrifugal device is re tracted the flange 44 will engage the inner I wall of the channel and carry the lever inwardly until the toggle is moved across center, and the lever will be moved a further distance by the action of the spring, thereby I carrying the inner wall of the channel away from the flange and again spacing the latter from both Walls of the channel. This centrifugal device may be assembled on the shaft "and its operation controlled in any suitable manner. As here shown, the weights are confined between the plate 8 and an outer retaining plate 45 which fits loosely about the shaft 2 and is retained thereon by a split ring 46 seated in a circumferential groove 47. Each weight has formed therethrough a radial slot 48 and the lugs 15 on the connecting plates 10 are of such a length that they will extend through the slots 48 in the respective weights. The width of the lug is substantially equal to the length of the slots 48 so that these lugs will have no appreciable radial .movement with relation to the weights. vided at their forward outer edges with lips 49 which engage the forward surface of the weights adjacent to the ends of the respective slots. 'The inner portions of the forward edges of the lugs are substantially flush withthe forward surfaces of the respective weights and are engaged by the retaining disk 45. The weights of the second centrifugal device are thus so connected with the contact members or weights of the centrifugally operated short-circuiting de vice that the two devices will move in unison and a single contractile band or spring 7 will control the action both of the short circuiting d vice and of the centrifugally operated mechanism for the brush controlling device. In order that the several weights of the second centrifugal device may move in unison and thus retain the several flanges 44 in circumferential alinement I have so connected. these weights one with the other that any movement of one weight will be, imparted to all the other weights. In the present device I have rotatably mounted upon the motor shaft 2 a ring or collar 50 having in its peripheral edge a series of notches or recesses 51, corresponding in number to the number of weights. Each weight has an arm 52 rigidly secured thereto, and preferably formed integral therewith, which extends beyond one end of the weight circinnferentialiy of the motor shaft, this arm being of such a character and so arranged that it will extend between the collar 50 and'the inner edge of an adjacent weight. 'Each arm has atthat end remote from the weight a projection or nose 53 which enters the corresponding recess in the collar 50-and is capable of a pivotal movement in that recess but is held against circumferential movement with relation to the collar. As will be noted the arrangement is such that when outward movement As here shown, the lugs are prothese weights also are moved outwardly. As a result each weight is held against outward movement until the centrifugal force is sufficient to cause all the weights to move outwardly, and the nward movement of the weights is similarly controlled. Consequently the several weights will'be caused to always move at the same time. The sev eral weights '42 are so arranged with rela tion one to the other that the projections on the several arms will be retained in the respective recesses in the collar during the movement of the weights. 'As here. shown, each weight has inone endthereof a recess 150 and at the other end thereof a projection 151 adapted to extend into the recess 150 of the adjacent weight. The arms 15:2 extend from and form the lower walls of the recesses 150 and each of thesearms 'hasa straightv outer edge, as shown at 152,

adapted to engage the innersurface of the overlying projection lfiL' The arrangement is such that when 1 the weights move outwardly by centrifugal force the projections 151 will be partially withdrawn from the recess 150 but these projections willfimanr tain contact with the straight port-ions 152 of the respective arms in all positions of the weights, as is shown in Fig. 3. This contact serves to hold the arm and its projecdeveloped in the two centrifugal devices will move the same outwardlyin unison, the short clrcuiting element contacting with the" commutator bars and short circu t-mg the latter and the other centrifugal device actuating the brush controlling device to cause that brush to be lifted out of contact with the commutator and retained in that posi:

tion. The parts will remain inthese posi{ tions so long as the speed of the motor is maintained but when the motor stops or v the speed falls below a predetermined speed the centrifugal devices will be retracted to their initial positions and the brush will be released so that it may be moved into contact. with the commutator by thespring' 21.

As has been stated, it is not essential that the brush be actually lifted out of contact with the commutator but if it is held against movement toward the commutator 'the' action of the latter will force it out of contact therewith In Fig.3 7 I have shown an ar rangement of the brush controlling device whereby this holding or snubbing action maybe attained. that figure the brush holderis indicated at 54; and the brush 55 is slidably mounted therein and pressed to-' ward thecommutator 56 by .a spring 57.

The brushholder has in one side thereof an opening orslot=58 in which'is mounted a brush engaging'member or clamping block 59 having an inclinedslot 60 through-which extends a. pin 61. The lever 62 is pivotally mounted at its rearend onthe brush holder,

asshown'at 63, and has its forward portion connected by means of a link 64 with the clamping block 59, the link and the lever being arranged to"constitute atoggle. The 6 connection between the link 6e and thelever' is a loose one so that the link mayihave' a limitedmovement with relation to the lever. As 'here showi1,.the link is provided with a s t 65 throughwhich the connectingpin'tifi extends. A bow spring 67' confinedbetween the link acts upon the toggle to complete the movement of the'leve'r when it has been moved across center. It'will be noted that in V the position shown in Fig. 7 the link extends downwardly at'ana'ngle to the lever and the inner edge of the clamping block extends but a short distance into the brush holder, the brush being spaced from the rear wall of the brush holderso that the brush is free to move toward the commutator under the the connecting pinsat the respective ends'of influence of the spring 57. When the lever.

62 ismoved upwardly the. action of the toggleforcesthe clamping block rearwardly,

thereby pressingthe brush against the'rear wall of the guideway and the brush holder and frictionally holding the same against movement under the influence of thespring 57 As has'been explained the action of the A commutator on the brush will move the same outwardlyso'that itwill have little,

if any, contact with the commutator; When" the lever' is' moved inwardly the clamping block will be movedforwardly and the brush released for movement toward the commutator.

In-Fig. 8 have shown a slightly modified I form of'a'device for-lifting the brush out of contact with the commutator. The brustdi 11 5 holder, brush and commutator are arrange substantially asshown' in Fig. 7 but I here employ two' clamping blocks 'or' friction members68 and 69 which are provided with inclined slots 70 through which extend pins- 7l:and 7 2 on' which the blocksare respective- I 1y slidably mounted. The rear block 68 has a rearwardly projecting. portion in which is mounted a pin 73 and a spring 74: confined: on the pins 7 3 and 71 tendsto move the block 68 forwardly and to press the same against the brush 55. The lever 7 5 is pivotally mountedatits rear end on the ends of the pin 71 and has its forward portion connect-' vedby a link 76 with the forwardclamping block 69, the link and the lever constituting a-toggle as above described'andh'aving sub-' stantially the operation of the device in Figs. 1 to 4.-' In this form .of the devicealso the rear clamping block is normally pressed for {ward against the brush but the frictional contact is not sufficient to materially restrict the movement v of the brush under the influence" of the spring'57. The first rearward movement of the forward clamping member 69. presses both thebrush and the rear clamp-V ing block rearwardly so that the brush will be clampedbetween the two blocks and because of the inclined arrangement of the, slots inthe blocks will be lifted out of engagement with the commutator.

'In F'g. 9 I have shown a different form ward clamping block. In this figure the brush holder, brush, commutator, lever and rear clamping block-are substantially the same as shown in Fig. 8 but the forward clamping block 77 is, provided in its forward edge with recesses 7 8 which impart a camshape thereto, and are engaged by a.

projectionor ro1ler7 9 on the lever 75. -The action of the spring'flton the rear block 7 8 causes this block to press the brush forward lyand the brush presses, the forward block against the rolleror projection 79. The roller 79 in riding over the projection between the two recesses 78 will force the forward.

clamping block rearwardly and" cause the brush-to be clamped between thetwo blocks. After the roller has passed the projection on the block it will seat itself in the recess and will be retained in this position until pres.

sure is applied thereto. While the clamping,

blocks; will" move forward slightly when the roller enters the outer recess this forward moveinent will not be sufficient to materially decrease the clamping action and the brushwill be held as before.

'In Fig. 10 I have shown a brush lifting device similar to that shown in Figs. 1 to 4:

but, have applied the same to a commutator onwhich the bars are radially arranged on the face of the commutator instead of being arranged peripherally thereof. Inthat figure the motor shaft isshown at 80, the com- ;mutatcr at 81, the commutator bars at 82, and

the brush holder 17, brush 20, lever'30 and clamping blocks 26 and 27 are substantially the same construction and arrangement as shown in Figs. 1 to 4. Butthe brush holder instead of. being radially arranged is arranged substantially parallel with the axis of the motor shaft. Across bar 31, at what is now the inner end of the, lever 30, projects into a circumferential groove 83 in a .collar 84 slidably mounted on the motor shaft and forced rearwardly by a spring 85.

It will be noted that the groove 83 is of such width thatthe lever will be maintained.

at an intermediate position between the walls of connectionbetween the lever and the for-v of the groove when the brush lifting device is in either position, as has been above described; The collar or'sleeve 84 carries a series of short circuiting elements 86 which are brought into line with thecommutator bars 82 by the axial movement-of the sleeve 84, this movement being imparted to the.

sleeve by a push rod 87 which may be actuated in any suitable manner but is usually operated by a centrifugal mechanism connected'with the .motor shaft. It will be.

noted that when the thrust rod moves the sleeve against the tension of thespring 85 it not only brings the shortcircuiting ele-;

ment into a position to engage the commutator bars but it also .actuates the lever 30 ofithe brush lifting device .thus causing the brush to be moved away' from thecommutator bars.

In Fig. 11 I have shown another mechathe clamping blocks willbe moved upwardly and forwardly. A lever 97i s pivotally supported on-the ends of the pin 96 on the forward side of the brush holder 'and has its rearportion connectedby means of a link 98 with the rearclamping block 93. A 'spri-ngf99 .is connected with the forward clamping block and with the lever and controls the toggle comprising thelever and the link in substantiallythe manner above described. Extending inwardly from, the

forward end of the lever is an arm 100, the

inner end of, which extends into a circum ferential groove 101 formed in a collar 102" slidably mounted; on the motor shaft 88. Connected with this collar is a thrust rod 103 which may be operated in any suitable manner, as by a centrifugal device connected with'the motor shaft. It. will be apparentfthat' this push rod will move the collar 102 in one direction orthe other and that this movement will cause the lever Q? to be moved from one positiont-o the other.

The short circuiting device is shown in the form of a series of resilient fingers 104 car- 'ried by the collar 102,and so arranged that it can be moved into and out of contact with the commutator bars'by the movement of the collar. h

lVhile I have shown and described certain embodiments of my invention I wish it to be understood that I do not desire to be limited to the details-thereof as various modifications may; occur to a person skilled in the art. c

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

1. In a motor comprising a commutator and a brush holder having a stationary guideway, a brush supported in said guideway for movement therein toward and from said commutator, a device movably mounted at one side of said guideway to move said brush laterally in said guideway and hold the same against movement toward said commutator, and centrit'ugally controlled means to actuate said device.

2. In a motor comprising a commutator and a brush holder having a stationary guideway, a brush supported in said guideway for movement toward and from .said commutator, said brush holder having an opening in a side wall otsaid guideway, a detent mounted for movement in said open ing in said brush holder, a device connected with said detent to cause the same to engage said brush and hold the latter against movement toward said commutator, and centrifugally operated means to actuate said device. 7

3. In a motor comprising a commutator and a brush holder having a stationary guideway, a brush supported insaid guideway for movement toward and from said commutator, said brush holderhaving an opening in a side wall of said guideway, a frictional clamping member mounted for movement in said opening in said brush holder, a device connected with said clamping memberto cause the same to engage said brush and press the latter toward the opposite side of said. brush holder, and centrifugally operated means for actuating said device.

L. In a motor comprising a commutator and a brush holder having a stationary guideway, abrush supported in said guide.

way for movement therein toward and from said commutator, a device movably mounted at one s1de of said guideway to engage said brush and move the same'outwardly in said guideway, and centritugally controlled means to actuate said device.

5. In a motor comprising a brush holder having a statlonary guideway, a brush supsaid brush holder for movement therein toward and from said commutator, brush engaging members mounted at opposite sides of said brush, yieldable means to press one of said members toward said brush, and centritugally controlled means to cause the other of said members to engage said brush and move the same against the pressure ofthe first mentioned means.

8. In a motor comprising a commutator and a brush holder, a brush supported by said brush holder for movement therein toward and from said commutator, brush en gaging members mounted on opposite sides of said brush. means to cause said brush engaging members to move upwardly and laterally, a spring acting on one. of said members to move the same toward said brush, and centritugally controlled means to cause the other of said brush engaging members to move said brush and the first men'- tioned brush engaging member against the action of said spring. I

9. In a motor comprisinga commutator and a brush holder,- a brush supported by said brush holder for movement toward and from said, commutator, brush engaging members movably mounted on opposite sides bers to move the same toward said brush and away from said commutator, whereby the action of the last mentioned member will cause both brush engaging members and the commutator V and a brush holder, a brush supported by brush to be moved away from said commutator.

10. In a motor comprising a commutator and a brush holder, a brush supported. by said brush holder for movement toward and from said commutator, brush engaging members mountedon opposite sides of the brush for movement with relation one to the other, means for causing said brush engaging members to move in substantially parallel paths diagonal to said brush holder,

- a spring acting on one of said brush engagbrush and toward said. commutator, a device for causing the other oi said brush engaging members to engage said brush, press the same against the'first mentioned brush,

engaging member and to then move both brush engaging members and said brush away from said commutator, and centrifugally controlled means for actuating said device.

11.. In a motor comprising a commutator and a brush holder, a brush supported by said brush holder for move ienttoward and from said commutator, brush engaging members mounted on opposite sides of said brush for movement with re ition one to the other and toward and from said commutator, a spring acting on one of said brush engaging members to move the same toward said brush, a lever extending transversely to said brush holder and pivotally supported near said spring actuated brush engaging member, a connnection between said lever and the other brush engaging member to cause the latter to engage said brush and move the same laterally against th pressure of the first mentioned brush engaging member and away from said commutator, and centrifugally controlled means for actuating said lever.

12. In amotor comprising a commutator and a brush holder, a brush supported by said brush holder for movement toward and from said commutator, brush engaging members mounted on opposite'sides of said brush for movement with relation one to the other and toward and from said commutator, a spring acting on one of said brush engaging members to move the same toward said brush, a toggle connected with the other brush engaging memberfto cause the same to engage said brush, and centrifugally controlled. means for actuating said toggle.

13. 'In a motor comprising a commutator and a brush holder, a brush supported by said brush holder for movement therein toward and from said commutator, a member arrangedto engage said brush and hold the same against movement toward said commutator, 'a lever mounted for movement about a fixed axis, a link pivotally connected with said lever and with said brush engaging member, and cen'tri'fugally controlled means for actuating said lever.-

14. In motor comprising a commutator and a brush holder, a brush supported by .aid brush holder for movement toward and from said commutator, saidbrush holder having slots in the opposite sides thereof, clamping members movably mounted in the respective slots andeach having an inclined slot therein, pins extending through in the respective clamping members to guide the same toward and'itrom said commutator,

' a spring acting on one of said clampingthe slots members to press the same toward the brush, a lever mounted on a fixed axis, a link connecting said lever with the other clamping member, and centrifugally controlled means for actuating said lever.

15. In a motor comprising commutator and a brush holder, a brush supported by said brush holder for movement toward and 'said lever to hold, the same'in the position to which it has been moved, and centrist ugally controlled means for actuating said lever.

16. In a motor 'com rising a commutator and a brush holder, a brush supported by said brush holder for movement toward and from said commutator, said brush holder having slots in the opposite sides thereof, a device to engage'said brush and hold the same against movement toward said commutator, a-lcver operatively connected with said device, means to move said lever to the limit of its movement in either direction after initial movement has been imparted thereto, said lever havlng a channel arranged circumlerentially with relation to the axis of said commutator, and a centrifugal device rotat-' able with said commutator and comprising a part extending into said channel, said part being so arranged that when the centrifugal device moves in either direction said part will engage a wall of said channel and impartinitial movement to said lever, and

when said part has reached the limitofits movement in said direction, further move ment' imparted to said'lever will. move the wall of said channel out of engagement with said part of said centrifugaldevice.

17. In a motor comprising a commutator and a brush, means to support said brush tormovement toward and from said commutator, a device to prevent the movement of said brush toward said commutator, an actuating device for the first mentioned device, acentrifugal device mounted for rotation about the axis of said commutator and comprising a plurality of radially slidablc weights, a yieldable device for resisting the outward movement of said weights by centrifugal force, means for connecting said weights one with the other to cause them to move outwardly in unison,and means for operatively connecting said centrifugal device with the'actuating device for said first mentioned device.

18. In a motor comprising a commutator and a brush controlling mechanism'rhaving an actuating member provided with a laterally extending channel, a centrifugal device rotatable with said commutator and comprising a series of radially slidable weights arranged about the axis of said commutator and each having a peripheral flange, the several flanges being arranged in circumferential alinement and extending into the channel of said actuating member, a resilient device to resist the outward movement of said weights, and means to cause said weights to move in unison. V

19. In amotor comprising a commutator shaft, a commutator mounted thereon, and

brush controlling mechanism comprising an actuating member, a centrifugal device comprising a series of weights arranged circumferentially of said shaft, rotatable therewith and mounted :for radial sliding movement, a collar rotatably mounted on said shaft, arms carried by the several weights, extending circumferentially of said shaft and pivotally connected with said collar to cause said collar to move with said weights in both directions, a contractile band to resist the outward movement of said weights, said centrifugal device (and said actuating member having cooperating parts to operatively connect the same one to the other.

20. In a motor comprising a commutator shaft, a commutator mounted thereon and a brush controlling mechanism, comprising an actuating member, a centrifugal-device comprising a series of radially movable weights arranged circumferentially of said shaft and rotatable therewith, a collar rotatably mounted on said shaft and having a circumferentially arranged series of recesses, each of said weights havingv an arm extendinglaterally therefrom about said shaft and provided at its end with apart pivotally mounted in one of said recesses, whereby the outward movement of one weight'will-impart rotatory movement to said collar and thus actuate the other weights, a yieldable device to resist the outward movement of said weights, and means to operatively connect said centrifugal-device with said actuating member. i

21. In a motor comprising a motor shaft and a commutator mounted thereon and havinga circumferentially arranged series of contact bars, a brush lifting device, a short circuiting device for said commutator comprising a series of contact members arranged circumferentially of said shaft and movable by centrifugal force into engagement wit said contact bars, a centrifugal device comprising a series of weights mounted about said shaft and rotatable therewith, means for operatively connecting said centrifugal weights arranged circumferentially of said shaftadjacent to said short circuiting device, said weightsbeing connected with the corresponding contact members ofsaid short circuiting' device for radial movement therewith, acontractile band extending 5 about the contact members of said short circuiting device to resist the outward movement ofsaid contact members and of said weights, and means for operatively connecting said centrifugal device "with saidbrush lifting device,

' 28. In a motor comprising a motor shaft and a commutator carried thereby and comprising a circumferential series of contact bars, a brush lifting device, a centrifugal device operatively connected with said brush lifting device and comprising a series of weights arranged circumferentially of said motor-shaft, a short circuiting device comprising .a' series of contact members arranged circumferentially of said motor shaft between said centrifugal device and said commutator, said contact members being movable by centrifugal force into engagement with the contact bars of said commutator, means for connecting the contact members of said short circuiting device with theweights of said centrifugal device to cause thesame to move in unison, and a contractile band extendingabout said short circuiting device .to resist the outward movement thereof and of said centrifugal device.

QL-In a motor-comprising a motor shaft and 'acommutator carried thereby and con-1 prising a circumferential series of contact bars, a brush lifting device, a centrifugal device operatively-connected with said brush lifting device and comprising a series of weights arranged circumferentially of said motor shaft, a short circuiting device comprising a series of contact members arranged circumferentially of said motorYshaft'between said centrifugal device-and saidcommutator, said contact members being movable by centrifugal force into engagement with the contact bars of said commutator, means for connecting the contact members of said short circuiting device with the weights of said centrifugal device to cause the same to move in unison, a contractile band extending about said short circuiting device to resist the outward movement thereof and of said centrifugal device, and an obstruction arranged in the path of said contractile band when the latter is in either its contracted or expanded position.

25. In a motor comprising a motor shaft and a commutator carried thereby and comprising a circumferential series of contact bars, a brush lifting device, a centrifugal device operatively connected with said. brush lifting device and comprising a series of weights arranged circumferentially of said motor shaft, a short circuiting device comprising a series of contact members arranged. circumferentially of said motor shaft :between said centrifugal device and said commutator, said'contact members being movable by centrifugal force into engagement with the contact bars of said commutator, means for connecting the contact members of said short circuiting device with the Weights of said centrifugal device to cause the same to move in unison, a contractile band extending about said short circuiting device to resist I the outward movement thereof and of said centrifugal device, and means for connecting the weights of said centrifugal device one with the other to cause them to move radially in unison.

26. In a motor comprising a motor shaft and a commutator carried thereby and comprising a. circumferential series of contact bars, abrush lifting devicefa centrifugal device operatively connected with said brush lifting device and comprising a series of weights arranged circumferentially of said motor shaft, each of said weights having an opening therethrough, a short circuiting device comprising a series of contact members arranged circumferentially of said shaft between said centrifugal device and said commutaton'a series of connecting members interposed between the contact members of said short circuiting device to divide the same into groups, each of said connecting members having a part seatedin the openingof the adjacent weight of said centrifugal device and held against movement relatively thereto, and a yieldable member acting on said weights and said-connecting members to thereof.

resist the outward movement 27. In a motor comprising ajmotor shaft and a commutator carried thereby and'com- -prisinga circumferential series of contact bars, a brush lifting device, a centrifugal device operatlvely connected with said brush lifting device and comprising a. series of weights arranged circumferentially of said tween said centrifugal device and said com- 7 mutator, a plurality of connecting plates arranged in pairs and interposed at intervals between the contact members of said short circuiting device, the connecting plates of each pair having oppositely extending portions to form seats for the inner ends of said contact members, the connecting plates of each pair having projections extending through the openings. in the adjacent weights of said cent'rifugal device to'hold the same against movement relatively there to, and a contractilecband extending about saidshort circuiting device and engaging said contact members and said connecting plates to resist theout-ward movement thereof.

28. In a motor comprising-a motor shaft and a commutator carried thereby and comprising a circumferential series of contact bars, a brush lifting device, a centrifugal device operatively connected with said brush lifting device and comprising a series of weights arranged circumferentially of said motor shaft, each of said weights having an opening therethrough, a short circuiting device comprising a series of contact members arranged circumferentially. of said shaft between said. c'entrifugal device and said commutator, a-plurality of connecting plates arranged inpairs'and interposed at intervals between the contact members of said short circuiting device, the connecting plates of each pair having oppositely extending portions to form seats for the inner ends of said contact members, the connecting plates of each pair having projections extending through the openings in the adjacent weights of said centrifugal device to hold the same against movement relatively thereto, a contractile band extending about said short circuiting device and engaging said contact members and said connecting plates to resist the outward 'movement thereof, a disk mounted about said shaft I bet-ween said short circuiting device and said centrifugal device and having radial slots through which the projections on said connecting plates extend, said disk having an annular rib arranged to engage said con tractile band and resist its movement when ture hereto.

GEORGE H. LELAND,

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