US1231844A - Brush-lifting device. - Google Patents

Description

A. J. BROWN.

BRUSH LIFTING DEVICE. APPLICATION FILED AUG.3.1914.

, W-M-M 2 1" "1' Patend July s, 1917.

ARTHUR J'. BROWN, OF MILWAUKEE, ./ISCONSIN, ASSIG'NOR TO ALLIS-CHALIVIERS FIANUFACTURING COMPANY, OF MILE? DELAWARE.

AUKEE, Vi/'ISCONSIN, A CGRPORATIGN OF BRUSH-LIFTING DEVICE.

Application led August 3, 1914.

To all whom t may concern.'

Be it known that iir-rrnun J. BuowN, a citizen of the United States, residing at Milwaukee, in the county of hililwaukee and State of l/isconsin, has invented a certain new and useful Improvement in Brush- Lifting Devices, of which the following is a specification.

rIhis invention relates in general to dynamo-electric machines, and has particular relation to such machines of the commutator type as require, for eflicient operation, a temporary lifting of all or a part of the brushes.

In starting rotary converters having interpoles, from the alternating current side, there may be considerable sparking at the direct current brushes due to the action of the interpoles in increasing the magnetic flux that links that short-Circuited coils beneath the brushes, thus increasing the energy of these short-circuited coils at the time the circuit of such coils is interrupted by the corresponding commutator segments leaving the brushes. By raising all, except a l comparatively small number of the brushes, those remaining on the commutator being' of comparatively high resistance so as to limit the current to a value just sufficient to establish the direct current field in the proper direction, sparking at the direct current brushes is avoided, or greatly reduced. Then the machine is up to synchronous speed, the raised brushes may be moved to their normal operating condition in contact with the commutator surface.

It is an object of this invention to provide an improved mechanism for lifting brushes of a dynamo-electric machine of the commutator type, which is comparatively simple in construction and efficient in operation.

It is a further object of this invention to provide an improved construction of brushlifting mechanism, wherein the current conducting element between the brushes and the brush holder or cross-connecting ring is utilized as a portion of the brush-lifting mechanism.

These and other objects are attained by this invention, the various novel features of which will appear from the description and drawings, disclosing one embodiment Specification of Letters Patent.

Patented July 3, 1917.

Serial No. 555,307.

of such invention, and will be particularly pointed out in the claims.

ln the accompanying drawings:

Figure 1 is a view in elevation of a portion of a dynamo-electric machine of the comn'iutator type, with parts in section, the machine being provided with brush-lifting mechanism embodying this invention.

Fig. 2 is an end view of a portion of a dynamo-electric machine, showing the brush-holder supports and brush-lifting mechanism of Fig. 1.

Fig. 3 is an end view of a brush-holder support and a portion of a modified form of brush-lifting mechanism.

Fig. 4 is a view similar to Fig. 3, showing a further modification of the brushlifting mechanism.

Fig. 5 is a front elevation of a portion of a brush-lifting mechanism such as is shown in Fig. 4.

As shown in the drawings, A represents the armature of a dynamo-electric machine which is provided with a commutator C. A frame 11, suitably held in place, as from the yoke of the machine or separately supported, acts as a support and guide for a supporting frame 12, the latter preferably being capable of limited circumferential movement relative to the frame 11. However, these parts may be of any ordinary and suitable construction to provide the proper support for a plurality of brushholder supports or forks 13, which are spaced about the commutator and are secured to the supporting frame 1Q, as by means of bolts 14 and nuts 15, the connection between these parts being such as to electrically insulate the parts 13 from the supporting frame 12,

At the radially inner end of each brushholder fork 13, a brush rod 17 is held in place in any suitable manner. A plurality of brush-holders 18 are suitably secured on the brush rod 17. Brushes 19 are slidable in recessed portions of the brush-holders 18 and are resiliently urged into engagement with the commutator surface by means of spring-pressed follower arms 20. Flexible connections 21, of conducting material, serve to electrically connect the brushes to the brush-holders. To provide for lifting all, or any number of brushes, as may be desired, from the commutator, each of the brushes to be lifted has secured to it, as by means of a rivet or screw, a semi-flexible or rigid member 23.

A spindle or shaft 25 is mounted to rotate in the spaced arms of the brush-holder fork 13, and one or more spaced arms 2G are secured thereto. Levers or links 27 are pivoted on a rod 28 secured to the ends of the arms 26. A plurality of levers 29 are pivotally mounted on a rod or spindle 30, fixed in position and supported in the arms of the brush-holder fork 13. The levers 29 are disposed opposite the brushes 19 and are urged to move in a clockwise direction by one or more springs 31. One of these springs may be arranged for each of the levers 29, as shown, one end of the springs being turned over a stop 32, in the form of a rod, supported and held in place between the arms of the brush-holder fork 13, and the other end being turned over a portion of the lever 29. Movement of the levers 29 in a clockwise direction is limited by engagement of a portion of each lever with one of the stops 32. The levers or links 27 are connected to the corresponding levers 29 through the links 34, pivoted at one end to the levers 27 and at the other end to the levers 29. Each link 34 is provided with a pin or projection 35, between which and the end face 36 of the corresponding lever 29 the brush-lifting member 23 is disposed. llhile the brushes are in engagement with the commutator surface, the parts ofthe brush-lifting mechanism are so disposed that the lifting connection 23 is free to move between the end face 36 of the lever 29 and the pin 35, to accommodate for wear of the brushes.

A lever 41 is secured at one end to the spindle or shaft 25, and, at the other end, as indicated at 43, to an actuating member 45. The connection between the members 41 and 45 may be anything suitable, but in the preferred arrangement the portions of the member 45 that are connected to the levers 41 are insulated from each other in any suitable manner. As a. means for actuating the member 45, a lever 43 is pivoted at one end, at 49, vto the supporting frame 12, and a pin 51, secured to such lever adjacent the pivotal point, occupies a slot 52 in a projecting portion 53 of the member 45.

lVith the parts in the positions shown in Figs. 1 and 2, the brushes are in engagement with the commutator surface. To raise the brushes, as during the starting operation of the machine, the lever 43 is operated, by movement in an anti-clockwise direction, to shift the member 45, through the pin and slot connection 51, 52, in any anti-clockwise direction, to cause actuation of the lever 41 and the arms 26 and rods 28. The levers 27 of the brushes to be lifted are thus actuated, and as the spring 31 is suiiicient at this time to hold the levers 29 against anti-clockwise movement, the link 34 moves relatively to the lever 29, causing the pin or projection 35 to grip a portion of the member between such pin 35 and the end face 36 of the lever 29. When the member or lifting connection 23 is so gripped, the connection between the link 34 and the lever 29 is, for purposes of movement in an anti-clockwise direction, a positive one, and this lever is moved against the tension of the spring 31, causing the movement of the member 23 and consequent movement of the attached brush from the commutator surface. The full raised position of the brushes may be attained when the lever 43 has moved through slightly less than 180 degrees. The reverse operation of the lever 4S from this latter position, returns the actuating mechanism to normal position and permits the springlpressed followers 20 to return the brushes into engagement with the commutator surface, the springs 31 acting on the levers 29 to assist in releasing the grip of the pins 35 from the lifting members 23.

By making the members 23 of such length that a portion thereof will be gripped, even when the brush is in full-worn condition, it will be apparent that there is no necessity for any adjustment of the brush-lifting mechanism to accommodate for wear of the brushes at any time after the brushes have been once inserted in the brush-holders and the parts of the lifting mechanism properly connected with each member 23 disposed between a part 29 and a pin 35 of part 34. If desired, the part 23 may be insulated from the brush, but the same is not necessary.

ln the modification shown in Fig. 3, the part 23a serves both as a means for lifting the brush and as a means for electrically connecting the brush with the brush-holder support or fork 13.

the brush, is rigid, or flexible only to such an extent as will not prevent this member from always maintaining itself in .proper position between the oppositely disposed gripping members. The outer portion 71 of this member 23et is quite flexible and of such length as to properly accommodate for any ordinary wear of the brushes, and is connected to a conducting bar 72 which is electrically and mechanically connected to the spaced arms of the brush-holder fork 13. The entire connection between a brush and the bar 72 may be of flexible, hollow-woven material, and a rigid core may be inserted in the lower part thereof to secure the required stiffness. Instead of the specific gripping arrangement shown in Figs. 1 and 2, the link 34a, having its end portion camshaped, as indicated at 35a, is connected to ln this construction, 'the part of the lifting member 23a adjacent that the movement of that part of the member 23a that is adjacent the brush, shall be in a straight line. The actuating parts and the operation of the device are quite similar to that described in connection with the form of the invention shown in Figs. l and 2, the main dilerence being that a single member acts both for brush-lifting purposes and to electrically connect the brush to the brush-holder support.

ln the modication shown in Figs. a and 5, as in the modification shown in Fig. 3, the member 23h serves both as a. brush-lift ing member and as a means for electrically connecting the brush to the brush-holder support. ln this construction, the member 23h is in the form of a flexible connection of conducting material and of sufficient length to accommodate for any wear of the brushes, and is connected at its outer end to a conducting bar 8l which is secured, as by bolts or screws 82, to a plurality of arms 2Gb mounted on the pivot shaft 25. A flexible connection 83 of conducting material, connected to the bar 8l and the brush-holder support 13, electrically connects these parts.

in the operation of the brush-lifting mechanism of these figures the arms 26 serve to lift the brushes, through the conducting bars 8l and flexible connections 23h, and, when the actuating parts are returned to normal position, the spring-pressed follower 2O serves to return the brush into engagement with the commutator surface.

t will be apparent that, in accordance with this invention, a brush-lifting mechanism is provided in which there is no necessity for any adustment of the parts to accommodate for wear of the brushes after the mechanism has been once installed, the connection between the brush and the actuating mechanism therefor being such that the brush is positively lifted the full distance independently of the condition of wear of the brushes.

It should be understood that it is not de- K sired to be limited to the eXact details of resiliently urging said brush into engagement with a current collecting surface of said machine, and means for moving said brush away from said collecting surface, said moving means comprising means for electrically connecting said brush to a terminal of said machine and being mechanically independent of said urging means.

2. In a dynamo-electric machine, a brushholder support, a brush-holder mounted thereon, a brush movably mounted on said brush-holder, means for resiliently urging said brush into engagement with a current collecting surface of said machine, a member electrically connected to said brush and serving as a portion of the electrical connection between said brush and a terminal of said machine, and means comprising mechanism cooperative with said connecting member for causing movement of said brush away from said collecting surface, said latter means being independent of said urging means.

3. ln a dynamo-electric machine, brushsupporting means, a brush mounted to move relatively to a portion of said supporting means, means operatively supported on said supporting means and operative to resiliently urge said brush into engagement with a current collecting surface of said machine, and means for moving said brush away from said collecting surface and comprising a rotatably mounted member and an operating connection between said member and said brush and independent of said urging means, a portion of said connection being flexible and forming a part of the means for electrically connecting said brush to a machine terminal.

et. In a dynamo-electric machine, a brushholder support, a. plurality of brush-holders mounted on said support, brushes in said brush-holders and movable to and from a collecting surface of said machine, means associated with each of said brushes for resiliently urging the corresponding brush into engagement with said collecting surface, means for supporting said urging means in operative position relative to said brushes, a connection of conducting material secured to each of said brushes, said connections forming a part of the means for electrically comiecting said brushes to a terminal of said machine, and actuating means cooperative with said connections of conducting material for moving said brushes away from said collecting surface, said actuating means being independent of said urging means and its support.

5. In a dynamo-electric machine, brushsupporting means, a brush mounted to move relatively thereto, means for moving said brush relatively to a portion of said supporting means and comprising actuating mechanism and a member secured to said brush, and means associated with said actuating mechanism and normally free of said member and effective through actuation of said mechanism to grip said member and cause movement of said brush.

G. In a dynamo-electric machine, a brushholder, a brush movable relatively thereto into and out of engagement with a collecting surface, means for causing movement of said brush away from said collecting surface, said means comprising a member' connected to said brush, a spring-pressed abutment, and mechanism for forcing said member against said abutment and causing the movement of said brush.

7. In a dynamo-electric machine, a brushholder, a brush mounted thereon and movable relatively thereto into and out of engagement with a collecting surface of the i machine, actuating mechanism for causing movement of said brush away from said collecting surface and comprising two normally spaced and relatively movable members, and a member normally disposed between said first members and connected to said brush, said actuating mechanism being effective on operation to grip the member connected to the brush between said relatively movable members and cause movement of said brush away from said collecting surface.

8. In a dynamo-electric machine, a brushholder, a brush mounted thereon and movable relatively thereto into and out of engagement with a collecting surface, means forming an electrical connection between said brush and a portion of said machine, a portion of said electrical connection being flexible, and means normally inactive and adapted to grip said connecting means and cause movement of Said brush from engagement with said collecting surface.

9. In a vdynamo-electric machine provided with a current collecting surface, a brushholder, a brush movably mounted in said holder, means for resiliently urging said brush into engagement with said collecting surface, means for supporting said urging means in operative position relatively to said brush, and mechanism for causing movement of said brush out of engagement with said collecting surface, said mechanism comprising a member secured to said brush,

pivotally connected elements having portions normally spaced apart to permit movement of said member therebetween, and means for forcing one of said portions toward the other to grip said member therebetween and draw said brush away from said collecting surface.

In testimony whereof, the signature of the inventor is affixed hereto in the presence of two witnesses.

ARTHUR J. BRO'WN.

Witnesses:

J. J. KANE, W. H. LIEBER.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. l

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