US2308671A - Commutator trimming tool - Google Patents

Description

Jan. 19, 1.943. BOWKER 2,308,671

COMMUTATOR TRIMMING' TOOL Filed April 27, 1940 s Sheets-Sheet 1 mmvroa E) VJ Bow 1 6a A T1 ORNEYS.

Jan. 19,, 1943. E. BOWKER 8, 1

- COMMUTATOR TRIMMING TOOL Filed April 27, 1940 s Sheets-Shet 2 A TTORNEYS.

Jan. 19, 1943. E BO KER 2,308,671

COMMUTATOR TRIMMING TOOL Filed April 27, 1940 3 Sheets-Sheet a ,4 0 H 4 w IL INVENTOR. .E'ruzzk B0 W266 A TTORNEYS.

Patented Jan. 19, 1943 UNITED STATE COMMUTATORTRIMMING TOOL Ervin Bowker, Fall River, Mass, assignor of one-' third to Douglas J. Richardson, Fall River, Mass; and one-third to Majar W. Wheelock,

Tiverton, R. 1.

Application April 27, 1940, Serial No. 332,096

Claims.

This invention relates to a tool for trimming or re-surfacing the commutator of an armature for an electric motor or generator; and has for one of its objects to provide a simple and inexpensive tool which may be used for the re-surfacing of the segment of a commutator and may also be used for cutting back the insulation between such segments.

Another object of this invention is to provide a tool which may be screw fed forward but which, when the forward feed has been completed, may be returned to starting position by a sliding action without the necessity of a reverse rotation comparable to the forward screw feeding of the device.

Another object of the invention is to provide a tool the use of which upon a commutator will sufflce to perform the desired function in much less time than comparable tools which I know of whereby the result on the work may be materially speeded up.

Another object of the invention is to so mount the bit of the device that it may be accurately adjusted such as through a threaded arrangement of a micrometer type.

Another object of the invention is to provide an extremely simple construction of bit holder with inherent resiliency which may be drawn together on the bit and the same securely held.

Another object of the invention is to provide an arrangement whereby the adjustment of the bit will be in a straight line toward and from the center of rotation and at right angles to the center of rotation at all points in its movement so that the same cutting edge of the bit is presented regardless of the point in the range of its movement.

Another object of the invention is to provide a simple chuck with an arrangement whereby a true centralizing mounting of the fixed part of the device upon the armature shaft may be had with an arrangement for the accommodation of varying sizes of armature shafts.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described, and particularly pointed out in the appended claims.

In the accompanying drawings:

Fig. 1 is a top plan view, partly in section, illustrating .my tool in full lines with the-armature upon which the device is to operate in dotted line;

Fig. 2 is an end view of my tool showing the armature shaft in section and taken on substantially line 2--2 of Fi 1 looking in the direction of the arrows;

Fig. 3 is an opposite end view of the device with the armature shaft removed; I

Fig. 4 is a section on line 4-4 of Fig. 1;

Fig. 5 is a, perspective view of the bit holder looking at one side thereof Fig. 6 is a perspective view of the bit holder looking at the other side thereof Fig. 'l is a perspective view of a carrier member through which various adjustments of the device may be readily made;

Fig. 8 is a sectional view of the member of Fig. 7 shown mounted in position and taken on line 8-8 of Fig. 1;

Fig. 9 is a sectional view of the cylindrical part of my device which is fixed to the armature shaft;

Fig. 10 is a section on substantially line Ill-40 of Fig. 9, illustrating the armature shaft and split sleeve thereabout mounted in position in this barrel member;

Fig. 11 is a perspective view of the arm which is mounted upon the member shown in Fig. 7 which engages the thread shown in Fig. 9;

Fig. 12 is a side elevation of the device with the undercutting tool for removing the insulation between the armature segment shown as mounted in position;

Fig. 13 is a section on line l3--I3 of Fig. 12;

Fig. 14 is a central sectional view of a modified form of the device.

It frequently occurs in electric generators or motors that the brushes which contact the commutator of the armature wear the commutator to such an extent that the commutator must be trimmed or re-cut in order that a smooth surface be provided. The tool to which this invention relates is a device which is mounted upon the armature shaft when such armature is held in a vice and by turning one of the parts of the device such retracing of the feeding stroke may be eliminated I have arranged for a'disengagement of the feed so that the parts may be returned to theiroriginal starting position by sliding. Further, it has been known in armature cutting tools that the bit which performs the cut is so mounted that it swings through an arc to and from the center about which the parts operate; and in order to improve upon this arrangement I have provided a mounting of the tool bit so that it moves in a plane at right angles to the center about which it turns and in a straight line toward and from such center. the tool, is presented to the work regardless of its point of adjustment.

After an armature commutator is turned down, it frequently occurs that the insulation between the segment is at the same level being turned down by the cutting of the tool; and it is necessary to undercut or cut away the insulation between the segments so that the brush which Thus, the same edge of.

the same opening from which the bit was taken,

and then by holding the part which previously rotated in the vice and disengaging the thread feed and the binding of the adjustment member so that the same may slide, I may slide the tool along the line parallel to the axis and by manually turning the same cut the insulation between the segments that the desired undercutting may be performed; and the following is a more detailed description of the present embodiment of this invention, illustrating the preierred means by which these advantageous results may be accomplished:

With reference to the drawings. designates generally an armature having a shaft [6. winding l1 and a commutator N3, the same being held between the jaws i9 and 26 of a vice at the workbench or other suitable location.

My device consists of a cylindrical barrel designated 2| which is fixed to the armature shaft, and a rotor part, designated generally 22, which may rotate about the barrel part as a bearing to carry a bit and provide a machine cut on the outer surface of the commutator.

The barrel part, designated generally 2i, is shown in section in Figs. 9 and 10 and consists of cylindrical block having a central cylindrical bore 23. The bore 23 extends but partially axially through the cylindrical block, while at its other end there is a square opening 26 centrally located. A slot 21 is cut across on a cord of the cylindrical circle, as illustrated in Fig. 10, so as to intersect the opening 26 and is arranged substantially parallel to one of the diagonals of the square central opening 26. A jaw 28 is pivoted in this slot 21 by pin 29 so that if any cylindrical member, such as the armature shaft l6 and sleeve 30 which extends about the same, is placed in this square opening 26, it will engage the walls thereof as at 3|, 32, which are in a V-shaped relation one to the other while the jaw 28 will engage the same as at 33 and provide a threepoint contact with the cylindrical portion to bind the sam centrally in the barrel member. A bolt 34 having a head 35 engaging a shoulder 36 in the recess 31 threadingly engages the jaw 28 as at 38 so as to draw the jaw into locking position.

Various sleeves 3lLare provided for accommodating armature shafts of diilerent diameters.

The rotor part of the device, designated generally 22, consists of a casting providing a cylindrical body 40 with a cylindrical bore 4| and a top or head projection 42 and a downwardly extending leg 43. This leg is split as at 44.- An abutment screw 46 is threaded in one portion of the leg 43 and abuts the other portion of the leg and serves to hold these portions of the leg 43 apart and prevent the inherent action tending to contract the bore 4i onto the cylindrical part 2! from exerting too great a binding action, thereon. A binding screw 45 is provided for drawing the split portions together. Should wear occur. however, adjustment is provided by means of these adjustments 45, 46 extending through these portions of the leg 43.

A substantially s uare recess 41 is milled in the head 42 in which the adjustment member,

designated generally 48, is slidably positioned. This member is provided with a V-shaped groove 48 to receive a V-shaped gib 58 located in the recess 41 and adjustable therein by means of the screws 5i extending through the side walls of the head 42. The adjustment of this gib is more or less a precision affair, and accordingly, these screws are set below the surface of the head 42 and are sealed in position by sealing wax or the like. A clamping screw 52 having a thumb handle 53 serves to move the gib 66 inwardly to blind1 the member 48 in a fixed position in the An arm designated generally 54 (see Figs. 1 and 11) is provided with an ear 55 which is rockably mounted by means of its bearing opening 56 upon the stud 51 formed by reducing to cylindrical formation one end of the member 48. This car fits against the abutment 58 formed by this reduction, while the pin 88 extends into the slot 6| in this manner to limit the movement of the arm rockably about this stud. The arm has an arcuate portion 62 which reaches within the threaded bushing 24 so that threads 63 on it may mesh with the thread 25 on this bushing. The arm is held in positions of adjustment in or out of engagement by a hand nut 64 engaging thread 65 on the end of the stud 51. The spring washer 66 serves to lock this nut in binding positions by acting through a washer 81 between it and the car 55.

At the opposite end of the adjustment member 48 I have provided a bit carrier 69 which fits within the recess 16 in the member 48. This bit carrier is recessed as at 1| and slotted as at 1|, while there is a lateral slot 12 in the opposite side of the carrier. A bit 14 fits within the recess 1! and is bound therein by the screw 15 having handle 16. The shank of this screw extends through the hole 11 in one side of the carrier and is in threaded engagement as at 18 with the other side of the carrier while extending through slot 86 in the member. The hub 18 of this handle engages the outer surface of the member 48 and draws the carrier into the recess 10 into binding position.

For vertical adjustment I provide a screw 8i having a flange 83 to extend into slot 12 in the bit carrier, the screw 8| being threaded into the member 48 which is recessed asat 84 to receive the flange 83 for greater range of adjustment of the bit carrier. By turning the handle 85, the bit carrier may be adjusted .to its desired position with the screw 15 partially set up to bind the bit in position; and after the correct height is acquired, a further binding of' the bit in its carrier may be had by reason of further turning of the handle 16. The slot 1i enables a proper binding of the bit 14 in position, while, when released, the

inherent resiliency in the carrier opens to permit release of the bit for removal of the same.

In order to rotate the part 22 about the part 2|, I have provided an arm extending upwardly at any convenient angle from the part 22 sufficient to provide the desired leverage for turning. Upon the upper edge of this arm a pin 96 is mounted and upon the pin there is a handle 81 which may rotate with reference to the pin.

For undercutting I provide a U-shaped carrier 81 having a leg 88 of a size to fit within the recess 1! from which the bit 14 is removed, the same being bound in position by the screw 15 and handle 16 in the same manner that the bit was bound in position. This carrier has mounted in its leg 89 a rotary cutter 98 operated by a crank reference to the head.

8| and handle 92, while there is a handle as positioned on the member 81 for moving the member 8 forward during an undercutting operation.

In some cases instead of the cylindrical barrel being internally threaded, I may form the barrel as illustrated in Fig. 14, the same being shown at I and provided with external threads IOI. In this case the rotor-member I02 is provided with an adjustable member I03; onthe lower surface thereof threads are provided at I94. Movement of this member is permitted toward and from the threads NH. The member I03 is normally urged radially outwardly from the threads by a shoe I05 and leaf spring I06, the member being shown operative to and from threaded engagement by cams I01 engaging the ends of the studs I08 and I09 and operated by handle H0 to force the member through the bronze plate H l to and from threaded engagement; the same tool adjustment of fit is provided in this member as heretofore provided in the other modified arrangement.

In operation, the armature, designated generally I5, is removed from the generator or motor and placed in a vice as illustrated in Fig. 1. The barrel part 2| of the device is clamped upon the armature shaft [6 so as to remain in fixed relation thereto. The adjustment member 48 is ad- Justed so that bit ll will commence at the edge of the armature commutator for cutting the same and is properly adjusted as to height. Thereafter, the arm 54 is swung into engagement with the threads 25 and is clamped into position by the hand nut 64. Then by grasping the handle 91 and turning the member 22, the member is rotated about the barrel and is fed forward by the screw 25 so that the tool will cut the commutator to true-up the same.

This cutting action usually causes the mica or other insulation between the sections of the commutator to be at the same surface as the commutator section, and this insulation must be undercut. For this undercutting I remove the armature from the vice and clamp the leg 43 of the device in the vice; then I remove the bit 14 and replace it with the carriage 81, adjusting the same to cause the tool 90 to take the proper depth cut by reason of the handle 85. Nut 64 is loosened and the arm 54 is thrown out of engagement with the thread, while the binding screw 53 is loosened so as to permit movement of the member 48 with The member 22 is held in fixed relation in a vice or other suitable support while the member 48 is fed forwardly by its handle 83, while at the same time the cutter 90 is rotated through the crank 9| and handle 92. After one cut is performed, while the leg 43 of the device is held in the vice, the armature is turned until the next insulation is presented to the cutter and the operation then repeated.

In this manner each undercutting may be performed by utilization of substantially the same device as performed the function of trimming the commutator of the armature.

The foregoing description is directed solely towards the construction illustrated, but I desire it to be understood that I reserve the privilege of resorting to all the mechanical changes to which the device is susceptible.

I claim:

1. In an armature commutator device, two relatively rotative parts, means for binding one part on the armature shaft, comprising an opening in the part with two flat surfaces in a V-shaped relation forming the wall of the opening, said bound part having at one section an outer surface forming a part of a cylinder, a jaw at said section within the completion of the cylinder to force a shaft to be bound against said fiat surfaces, a cutting tool carried by the other part, threads provided on one of said parts, and means on the other part for releasably engaging said threads for axially moving said parts upon relative rotation thereof.

2. In an armature commutator device, a cylindrical barrel part having an opening therein with two flat surfaces forming the wall of the opening and having a V-shaped relation one to the other, said barrel having at one section an outer surface forming a part of a cylinder, a jaw at said section within the completion of said cylindrical outer surface to force a shaft to be bound against said flat surfaces and bind the barrel part thereon, a rotary part revolvably and slidably mounted on the outer cylindrical surface of the barrel part, and disengageable threaded means on said parts for relatively axially moving the parts when relatively rotated with said means engaged.

3. In an armature commutator device, a cylindrical barrel part provided with means to clamp an armature shaft therein, said barrel part being providedv with a bore and internal threads, a rotary part revolvably and slidably mounted on the outer cylindrical surface of the barrel part and carrying a tool, an arm located in said .bore and swingably mounted on the rotary part to threadingly engage said internal threads to feed the tool when the parts are relatively rotated, means to clamp said arm in either engaged or disengaged position with said threads, and a handle mounted on said rotary part to revolve the same about said barrel for actuating said tool.

4. In an armature commutator device, two

relatively rotative and slidable parts, means for' binding one part on the armature shaft, a cutting tool carried by the other part, one of the parts being provided with a central threaded bore and an arm pivoted on the other part on an axis located at a point spaced from the axis of said bore and provided with threads engaging the threads of the bore for'relatively axially moving said parts upon relative rotation thereof, said arm being movable about said pivot to cause engagement or disengagement of said threads.

5. In an armature commutator device, a cylindrical barrel part provided with a V-shaped opening, a clamping jaw to clamp an armature shaft in said opening to hold the. same firmly therein, said barrel part being provided with a bore and internal threads, a rotary part revolvably and slidably mounted on the outer cylindrical surface of the barrel part, a member axially slidably mounted in said rotary part, a tool holder carried by said member at one end, threaded means to adjust said tool holder in a straight line toward and from the axial center of said barrel part, an arm swingably'mounted on the other end of said member to extend into said barrel and threadingly engage said internal threads, means to clamp said arm in either engaged or disengaged position with said threads, and a handle mounted on said rotary part to revolve the same about said barrel for actuating said tool.

ERVIN BOWKER.

h CERTIFICATE OF conmzc'rxon.

Patent No. 2,508,671. January 19, 151 .5.

ERVIN BOWKER.-'

It is hereby certified that error appears in the above numbered patent requiring correction as follows: In the grant, lines 5 and 111., and in the heading to the printed specification, name of sssignee, for "Majar w. wheelock" read "Major w. wheelock", as shown by the record Of.ass1gr1- ments in this office; and that the said Letters Patent should be read with this correction therein that the same may conform to the record for the case in the Patent office;

Signed and sealed this 9th day of March, A. D. 1915.

Henry Van A'rsdale, (Seal) Acting Commissioner of Patents.

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