US990722A - Power-driven tool for dressing commutators. - Google Patents

Description

R. S. FREEMAN.

POWER DRIVEN TOOL ma DRESSING OOMMUTATORS.

APPLICATION PILID NOV. 21,1910. 990,722. Patented Apr. 25, 1911.

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ROE S. FREEMAN, 01 ATLANTA, GEORGIA.

lllltlEJ'iET'E.

Specification of Letters Patent.

Patented Apr. 25, tl'tl lti.

' Application filed November 21, 1910. Serial Noflaflfififii.

To all whom, it may concern:

lie it known that l, ltoe S. l nnmii-iu, a citizen of the United States, residing; at Atlanta, in the county of Fulton and State of Georgian have invented certain new and use l'ul improvements in Pmverdh'iveu Tools 't'or Dressing (knnmut-ators, ot' which the following is a specification.

My invention relates to power driven hand tools, and more particularly to a too] ot tlm character especially designed for dressing the commututors ol' dynamo electric machines.

As is well known, trouble is constantly experienced with commutator-s owing to the tendency of the relatively soft copper bars to wear away faster than the mica used as insulation between them. This results in the formation of ridges on the eonnnutator which has the eti'ect of producing disstrolls sparking. .l leretotore in order to dress commutator-s worn in t'his'n'ianner, it has been necessary to remov v the armature from the in: chine in order that" the commutator may he brotw l'it in position to be operated upon by a milling mach ne or cutter of any well known type.

The primary object of the present invention is to obviate the necessity for removingthe armature from its hearings and to this end. the invention seeks to provide a hand tool driven by means of a flexible sl aft, and so designed that it; may be used to cut the mica from between the commutator bars without: removing the armature from the machine.

A further object; is to provide a strong.

compact and practical power driven. hand tool of this character which will ellectirely perform the work which it is designed to ac- COHIPllSl) and \Vllltll, at the same tune, \\'lll he cxtren'iely cheap and simple in construe non.

With the above objects in view, the'invention consists in the construction and an rangementof parts hereinafter described and claimed, and illustrated in the accompanying drawing, in which,

Figure 1 is a plan view otmy com plete device showing the same in position on a commutator; Fig. 2. is a side elevation of the same; Fig. 3 is a central horizontal section. parts being in elevation; and, Figs. 4 and 5 are a detail elevation and section respectiveiy, showing the method of mounting the supporting arms hereinafter described.

Referring to the drawings in detail, my improved tool comprises a handle l which may he formed of wood or othersuitiiible material. To this handle secured, as by means of a screw shank J, a forked yoke 3. Secured in openings in this yoke are a pair of alined hearings l, 5, held in position in the yoke by means of set screw t3. Journaled in these hearings is a shaft 7 over the end of which is adapted to lit a socket 8 attached to a flexible shaft 9.

Mounted on the shaft 7 between the forks of the yoke a. milling cutter 10 in the na ture of a circular saw and this cutter is held in place on the shaft by means of (-ilan'iping nuts 11. 12 screw threaded on the shaft. in this connection, it will be observed that the diameter of these nuts is less than that of the hearings 4-, 5, whereby. when one of said hearings is removed from its fork, the shatt'. together with the clamping nut on that side, may he shifted laterallv through the opening in the fork left. by the hearing" so that the nut on the other side may be unscrewed and thus the shaft and first mentioned nut may be withdrawn entirely from the forks thus permittiugthe cutter to be removed.

Referring partieul rly to Fig. 2, it will he observed that the depth or width of the yoke l is almost equal to the diameter of the cut ter. It. will also he observed that the ends of the forks, are substantially semicircular in shape as indicated at 3. it will tltere- 'tore he observed that owing to this shape and proportion of the parts the teeth of the.

cutter project slightly beyond the edge of the forks and thus when the tool is applied to a commutator such as t3, the bottom ed a e of the forks rest upon su h commutator and serve a support to guide the cutter along: the work. in order however to even more etl'ectively steady the cut ter and to support it when operatingat the end of the commutator, as shown in the drawings. i provide supporting arms 15, one of which is secured to the outside of each fork. Such arms are preferably slidahly mounted upon the yoke as by means of a barrel or casing 16 tl'irduggh which the arm is adapted to slide and in which is disposed a coil spring l7 surrounding the arm. A pin '18 passing through they arm engages such spring and also projects through a slot. it) formed in the barrel. This construction. it will be seen, permits the arms to yield when they are brought in con tact with the end wall 14 of the commutator so as to allow. the cutter to travel as far as the end of the yoke will permit.

d it. Wnl thus be seen that I have provided a small, compact and at the same time substantial power drivem hand tool which can be readiiy'upplied to any commutator without remov'ingit from its normal position and it is thought that the manyadvanteges of my Y invention will be readily appreciated by those familiar with such matters.

What I claim is: l. A tool for dresslng oommutators com- I prising e handle, a forked yoke carried thereby, a shaft extending throu h and j ourneled in both forks of said yo'e, a cutter mounted on said shaft between the forks of the yoke, and a supportin arm secured to eaeh side of saidyoke parallel therewith and projeotinghe end the end'thereof.

2. A tool or dressing commutators comprising a handle, a forked yoke carried thereby, ashaft journaled in said yoke, a cutter mounted on said shaftbetween the forks of the yoke, a supporting a'rm slidably.

mounted on each side of said yoke, and re silient means for normally maintaining said arm projected beyond the end of said yoke.

3. A tool of the class described, comprising. a forked yoke, 21 pair of alined bearings carried by the forks of said yoke, a shaft journaled in said bearings, a millin r cutter mounted on said shaft'between the iorks of said yoke, and clamping nuts fitted one-aid shaft and serving to hold said cutter in position,one of said bearings being removable, 1

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