US1707403A - Brush holder for revolving brushes - Google Patents

Description

April 2, 1929. J, os'r o 1,707,403 BRUSH HOLDER FOR REVOLVING BRUSHES Filed y 13. 1927 ZSheets-Sheet 1 April 2, 1929. J. K. KOSTKO 1,707,403

BRUSH HOLDER FOR REVOLVINGw BRUSHES 2 Sheets-Shee' Filed May 15. 1927;

d l ffrlfots'ika' UNITED STATES iii" PATENT err-ice s- EL R Re enues Ba an Applieation filed May 13,

This invention relates to improvements in statmnary commutators and revolving brush holders carrying brushes adapted to cooperate with stationery or with moving commutators.

The objects and featur s of this invention will appear from the description and drawings and will be more particularly po nted out in the claims.

in the accon ipanying diagrammatic drawings 1 and 2 snow two views of one embodiment of my invention, Figs. 3, 4: and 6., 7 show two views of two other embodiments, F shows one view of a fourth embodiment and Figs. 8, 9 and O are explanatory diagrams.

lllferring more particularly to Figs. 1 and 52, moun ed on the revolving shaft 2 of a motor generator is a spider 3 which carries any suitable number of brackets 9 insulatingly held to the spider 3 by means of the bolts 8. Each bracket 9 supports a pin 12 on which are pivotally mounted two pairs of scissor- like arms 10, 11 and 10, 11, one pair being" controlled by the coil spring 7, the other by the coil spring 7 and each spring tending to close one pair of scissorlike arms.

The stationary member of the dynamoelectric machine is provided with a number of brackets which support the stationary commutator 6. This commutator is circular and of i -shaped cross-section. The stem of the T is directed inwardly towards the shaft of the motor and the two sides of this stem, which are in planes perpendicular to the shaft, form the working surfaces or faces of the st lonary commutator which may have any desired numltier. of segments. These segments are radially insulated one from the other and held together by a metal ring 85 insulated from the commutator segments by strips of insulation 21 and preferably shrunk over the properly assembled T-shaped ments of 6,. lhe ring '-5 is carried by the bracket-3 20 and held in place by the ring 18 and the studs 19. This commutator is connected to a winding which is not shown but which is located on the stator or stationary member of the dynamoelectric machine.

@ppositely located brushes 4L, 5, which may be of carbon or any other suitable material, cooperate in pairs with the two radial workfaces of the T-shaped commutator and are ly held in operative relation to said faces by the two pairs of scissor-like arms 1227. Serial in). 191,100.

10, 11 and 10, 11, loosely pivoted on 12, as shown in Fig. 1, and controlled by the springs 7 and 7". Each brush carries on its outer end a metal cap ll, 15 and a pin l6, 17 passes through each brush and its cap. Each pin runs approximately parallel to the working face of the commutator, projects on each side of its brush and its axis is about parallel to a tangent to the outer circumference of the commutator. The arms 10 and 1.0 engage with the pin 16 of the brush 4 located on one side of the commutator segn'ients, while the arms 11, ll" similarly engage with the pin 17 of the oppositely located brush The pins 16 and 17 loosely fit int-o suitably shaped notches provided ineach of the arms as more clearly shown in Fig. 10. I

When the shaft 2 revolves 1t carrles w th it the brackets 9, the spring controlled arms 10, 11, 10, ll and the brushes 4, 5 with which they cooperate. The commutator 6 is stationary. The brushes l, 5 may be connected to a winding or windings on the revolving ember of the machine.

It is seen that relative movement between b ushes and the revolving; member is in no way hindered in an axial direction. Thus, if the commutator stationary and the shaft moves axially to and fro due, for instance, to end play the brushes remain in cooperative relation to the commutator, in other Words the whole brush surface normally in contact with a working face of the commutator remains contact with said face while the revolving member moves to and fro relative- 1y to the brush and in a direction at rightangles to the working face of the commutator. During such axial movement of the revolving member the hubs of the arms 10, 11, 10, 11 move on the pin 12 and the notches in said arms move. onthe pins 16 and 17. Then the revolving member moves axially the axial ilisplacement between original points of contact between'the pins forming part of said brushes and the notches in the arms 10, 11, 10, 11, and between pin 12 and the hubs of arms, is very considerably less than the concurrent axial displacement of the revolving member. In Figs. 1. and 2 the centrifugal force acting on the brushes 4.: and 5 increases the pressure on the pins 12, 16, 17 but does not materially affect the pressure of the brushes; on the working faces of the commutater, A brush readily removed for examination or replacement by pulling the corr ponding a m. ver have th e mm tat to a sufficient extent. and slipping the brush pin out of the notches in said arms.

It. will be readily understood that the working faces of the commutator need not be exactly at right an les to the axis of the machine or of that of the revolving member, the stem of the T may, for instance, have somewhat converging instead of parallel sides. Furthermore, it is not necessary to operate the brushes in groups of two. One of the brushes 4 or 5 in Fig. 1 can, of course, be omitted.

In the embodiment shown in Figs. 3 and 4 a U-shaped member 31 is secured to the bracket 9 by means of the rivet 34: and prevented from turning about said rivet by means of the pin 22. This U-shaped member forms a box-like brush holder adapted to guide the brush 5, provided with the metal cap 15, into operative relation with the radial working face of the con'nnutator 6. This commutator has but one working face and is of L-shaped cross section. The brush is yieldingly pressed into surface contact with the commutator face by means of the lever 25 loosely mounted on the pin 22 and under the control of the coil spring 26, one end of which passes through and is held in the hole 32 provided in one of the sides of the U-shaped member 31 while the other end of this spring presses against the lever 25. Shoulders provided in the sides of the member 31 limit the travel of the brush in the direction of the shaft and the cross member of the U-shaped piece limits the travel of the brush in the opposite direction. The brush 5 is also under the control of the spring 30, one end of which is attached to a hook held in the cap while the other is attached to the hook 87 mounted on a pin passing through the side members of 31. The spring 80 opposes the action. of the centrifugal force on the brush 5 and is preferably so dimensioned that in normal operation the brush 5 floats between the stops limiting its radial movement.

In the arrangen'ient shown in Figs. 3 and L the revolving brush 5 is free to remain in cooperative relation to the commutator face, in other words to retain a surface contact with said face, while the revolving member moves axially to and fro carrying the bracket 5) with it. This brush is held in yielding con tact with the coi'iunutator face by the lever 25 and spring 26 and the ctfcct of the centrifugal force on brush 5 is sutliciently counteracted by H 2 spring 30 to prevent said brush from being forced into intimate contact with the cross piece of the member 31. A considerable movement of the brush in an axial direction or of the revolving member along a line nor ma]. to the commutator face corresponds to only a slight codirectional displacement between original points of contact between parts of the mechanism which yieldingly hold the brush in contact with the working face of the commutator and which counteract lhe action. of the centrifugal force on the brush. Thus, a considerable axial displacement of the revolving member causes but a slight movement between the hub of the lever 25 and the pin :22, a slightmovement between the point of the lever 25 and the cap 15 of the brush and a slight movement between the ends of the spring 30 and the hooks with which said ends cooperate. By forcing the lever 25 back away from the brush 5 it is possible. to withdraw the latter from the guiding element 31 for inspection or replacement.

The arrangement shown in Fig. 5 differs from that illustrated in Fig 3 and i: in that the lever 33 which is quite similar to the lever 25 of Figs. 3 and 4: is so located with respect to the brush that it exerts on said brush a pressure having two components. One of these components yieldingly 'lorces aid brush into contact with the commutator .ace while the other opposes the action of the centri force on the brush To enable the levy c to perform this dual. function a part of the brush 5 is cut away so as to present a suitably inclined surface to the end of the lever 33. in 5 the sides of the guiding member 31 are shaped to suit the n'iodiiicd position of the pin 22 with respect to the brush in the embodiment shown in Figs. 6 and 7 the member 23 is shaped to guide the brush 3 into operative relation with the working face of the commutator 6 of L-shaped cross section. The sidemen'ibers of the guide {33 are hook-shaped and engage with the pin held in the bracket 9. These books limit the travel of the giiiide 23 in a radial direction. This guide is held approxinnitely in its 11o1 mal position by the flat spring @ne end of this spring is attached to the bracket at 86; the other end is provided with extensions 28 which cooperate vith welders of the guide 23 to prevent the books of the guide :25) from slipping off the pin 22. The brush 5 located within the upper end of the guid is held in yielding contact with the operating surface of the con'muitator by the lever 25 loosely mounted on the pin and under the control of the spri g 26. The travel of the, brush in a radial direction is limited inwardly by a part of the spring 2? and ouiwardlv bv I i l 1 l :3 1 71f I 1'! a wee. rouuocu conical knoo 1 r atnu'heo m the guide i223 and cooperating with a suitable ufr memos ush gear and the revolving r or to retain its operative or surface contac with the working face of the commutator, let it be assumed that normally the conditions are as exagg-iratedly depicted in Fig. 8. Let t e 'riginal points of contact between the brush 5 and the centr fue'al force opposing means be M and N ind let the original points of contact between the pin 22 and the hooks of t ic guiding member 523 be M and N. If the revolving member now moves from left to right so as to bring the pin into that position with relation to the working face of the counnutator 6 which is shown in Fig. 9, the brusl 5 willmoveinwardly to someextent,willreiainitssurface contact with the connnutator 6 and the conical mem ber 2 will be displaced on the brush 5 bring about a displacement between the original points of contact M and N as well as a displacement between the original poin s of contact M and N as shown in Fig. 9. But, whereas the revolving member of the dyn amoelectric machine, and with it the pin 22, has moved relatively to the commutator face through the distance a+b the codirectional displacement between the original points of contact M and N amounts to about one tenth of that distance while that between the orig inal points of contact M and N amounts to oven'less. Obviously, the same relative cisplacement would occur if the face of the commutator were correspondingly displaced with respect to the bracket 9. While the revolving member moves in the manner descr'bed in comiection with Figs. 8 and 9, the original points of contact between the hub of the lever and the pin 22 obviously undergo displacements quite similar to those between the points M and N. In this manner the worl; of friction between parts of the brush gear and bet-ween the brush and the brush gear, caused by the said axial displacements, is greatly reduced and sluggishness of brush avoided without it being necessary to subject the brush to such axial pressure as would involve undue friction losses between the brush and the comnmtator. In orcer to remove brush 5 of Figs. (5 and 7 for inspection or replacement, it necessary to pull the lever 25 away from the brush and slightly depress the spring 27 by means of its wings 28. Depression of the spring 21' also permits of the removal of the guide 23 by unhooking same from the pin 22.

It will be clear that various changes may be made in this disclosure without departing from the spirit of this invention, and it is, therefore, to be understood that this invention is not to be limited to the specific details here shown and described.

lVhat I claim is:

1. In a. dynamoeleclric machine having a stationary and a revolving member, a com mutator on one member having a working respect to the br member in o l y at right angles to th face a batantiall c axis of the machine, a brush carried by the other member and free to move with respect to said other member substantially parallel to the axis of the machine, means for producing relative rotation between the brush and the commutator, means for yieldinglypressing said brush into axial and surface c dict wit the working face of the commutator, and means for opposing a radial movement of the brush, said named means being constit-uted that in case of relative axial displacement between the brush and said oth member the axial displacement between original points of contact between brush and the most effective parts of the radial movement opposing means is less than the relative axial displacement between the brush and the other member.

2. A commutator having a working face, a revolving brush cooperating with the commutator and free to move rola .ely to 3 support along a line normal to the work 5 face of the commutator while retaining a surface contact witl said face, and mechanism for opposing the effect of centrifugal force on the brush along a line at angle to the normal to the working face of inc commutator charactenzcd by the that in case of relative motion between the brush and its support in direction normal to the coinmutator face the codirectional displacement between original points of contact between parts of said mechanism is less than the con-- current displacen'ient betwen the brush and its support.

3. In a dynamoelectric machine having a stationary and a revolving member, a commutator on one member having a working face substantially at right angles to the axis of the machine, a revolving brush carried by the other member, said brush cooperating with the commutator and free to move relatively to its support along a line normal to the work" ing face of the commutator while retaining a surface contact with said face, means for limiting the radial displacement of the brush characterized by the fact that in case of rclative motion between the brush and its support in a direction normal to the con'in'iutator face the codirectional displacement betweei the brush and said limiting means is than the concurrent displacement betw ion the brush and its support.

4:. A commutator having a working face, a revolving brush free to move relatively to its support along a line normal to the coinmutator face while retaining a surface contact with said face, means for guiding ti o brush into operative relation with the commutator face, means for yieldingly pressing said brush into contact with the commutator face, and mechanism associated with the guiding means characterized by the fact that in case of relative motion between the brush and its support in a direction normal to the commutator face the eodirectional displacement between original points of conta t between parts 01 said mechanism is less than the concurrent displacement between the brush and its support.

5. In a dynamoelectric machine, a commutator having a working "face substantially at right angles to the axis of the machine, a revolving brush. support, a brusl'i, means loosely pivoted on said support for re volving the brush and guiding it into operative relation with the con'imutator iace, said brush beingfree to move relatively to the support substantially parallel to the axis of the machine, and means For opposing a radial movement oil the brush said last nan'ied means being so constituted that in case of elative axial motion between the brush a nd the support the cooirectional displacement between original points oi contact between brush and the most effective parts of the radial movement opposing means is les than the axial displacement between the brush and said support.

6. In a dynamoelectric machine, a stationary commutator having a working face sub-- stantially at right angles to the axis of the machine, a revolving brush gear support comprising a pin, a brush, means loosely hinged on the pin for guiding the brush into operative relation to the commutator face and pressed against said pin by centrifugal force, means for yieldingly pressing the brush into operative contact with the commutator face, and retaining means providing a contact sun face between the brush and the guiding means adapted to take the centriihigal thrust of the brush on the guiding means, said surface being so formed and controlled that in case oi relative axial motion between the brush and the support the codirectional displacement between original points of contact between the lu'ush and said surface is less than the axial displacement between the brush an d the support 7. In a dyramoelectric mach ne, a stationary commutator loving a working tace substantially at right angles to the axis of the machine, a brush, a revolving brush gear adapted to guide the brush into operative relation to the commutator face, and means for yieldingly pressing the brush into or warm tive contact with the commutator and for counteracting the action oi the centrifugal force on the brush.

S. In a oynamoeleetric n'iachinc, a stationary commutator having aworlzing face substantially at right angles to the axis of the machine, a brush, a pin attached to the brush and approximately parallel to the working face of the commutator, a revolving brush gear support, means loosely pivoted on the support and loosely hinged about the l: rush pin for yicldingly pressing the brush into operative contact with the commutator face and for counteracting the etlfect of the centrifugal force on the brush.

In testimony whercot I atlix my signature this 6th day of May, 1927.

JAROSLAVV K. KOSTKO.

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