US3517540A - Commutator tool - Google Patents

Description

June 30, 1970 s. A. KOZMA, JR

COMMUTATOR TOOL Filed July 24, 1968 FIG.3

INVENTOR.

SOL A. KOZMA,JR.

United States Patent 0 3,517,540 COMMUTATOR TOOL Sol A. Kozma, Jr., Winston-Salem, N.C., assignor to Comm-Tang Corporation, Raleigh, N.C., a corporation of North Carolina Filed July 24, 1968, Ser. No. 747,308 Int. Cl. B21d 3/10 U.S. Cl. 72-414 10 Claims ABSTRACT OF THE DISCLOSURE A commutator tool for salvaging or straightening commutators having a plurality of segments and tangs and having a mating plunger and base wherein a commutator supported by the base will be cooperatively received within a channel in the plunger when the plunger and base are mated and the sloped lower edge of the plunger will raise the commutator tangs to a predetermined position.

BACKGROUND, BRIEF SUMMARY AND OBJECTIVES OF THE INVENTION The tremendous growth of battery-powered small household appliances such as toothbrushes, carving knives, vibrators and the like has placed a heavy requirement on industry to furnish small DC. motors for these items. commutator design and construction for these variously sized and rated motors have ranged from the locking ring segment mounting type commutator disclosed in U.S. Pat. No. 1,426,105 to the widely used segmenttang commutator disclosed in US. Pat. No. 3,080,615, and referred to hereinafter as the tang commutator.

The tang commutator provides bendable, extending tangs integral with the commutator segments which are crimped outwardly over the segments to retain the conductors extending from the motor windings, each seg ment carrying one tang which secures the one end turn of each armature winding of the motor. In the event a single conductor is not properly retained by a tang or the tang-crimping operation does not leave the external clearances of the commutator within certain limits, the entire commutator is classified as a reject and must be discarded even though it might be functionally sound and physically intact. The cost of reprocessing salvaging these devices for reuse has heretofore been prohibitive, consequently they are usually melted down for scrap or completely discarded.

The great quantities of commutators now required for motors in appliances and the like as previously discussed which have previously been discarded or junked have prompted the development of several embodiments of a functional and inexpensive commutator tool which will straighten and clean rejects removed from the production line and reopen the tangs at a preselected angular relationship with the segments of the commutator to enable the processed commutator to be used again on a production basis, even to the extent that the re-worked rejects may again be used in automatic machinery where critical tolerances must be maintained.

The commutator tool comprising the present invention is made up of two basic components which mate about a tang commutator to be reworked to raise the crimped tangs from the segments to a predetermined position having a selected angular relationship with the segments which constitute the outer periphery of the commutator. A movable plunger has a commutator-receiving channel and a lower, sloped edge which, when urged downwardly along the segment surfaces to engage the crimped tangs, will act as a wedge to raise the tangs away from that surface. A separate, stationary base supports the reject commutator rigidly, and the plunger is then forced down- 3,517,540 Patented June 30, 1970 ice wardly against the base to perform the salvaging operation on the crimped tangs of the commutator. An extractor is provided in the plunger to permit easy removal of the reprocessed device, in one embodiment this component comprising a spring-biased piston to expel the salvaged unit from the channel of the plunger.

From the foregoing background and summary of the invention, it will be apparent that an object of the present development is to provide a commutator tool of the type described that will permit the salvaging of production rejects which were heretofore junked or discarded.

Another object of the present invention is to provide a tool of the type described having two separate and matable portions which will reprocess rejected commutators having a plurality of segments and tangs within such tolerances that will permit the reuse of these de vices in automatic, production line machines.

A further object of the present invention is to provide a commutator tool of the type described which will raise previously crimped tangs away from the segment surfaces and to a predetermined, angular relationship with those surfaces.

Yet another object of the present invention is to provide a tool of the type described which will expel reprocessed tang commutators from within a receiving channel in the movable plunger to permit high production quantities of the devices to be handled.

These and other objects of the present invention will become apparent by referring to the following detailed description and accompanying drawings wherein like characters of reference designate similar elements throughout the several views.

FIGURE DESCRIPTION FIG. 1 is a perspective, exploded, cut away and sectional view of the primary embodiment of the present invention showing a tang commutator suspended between the movable plunger and stationary base of the tool wherein the cut away sections disclose the spring-biased piston retained in the channel of the plunger.

FIG. 2 is a side elevational, sectional view of another embodiment of the present invention wherein the separate tool elements, the movable plunger and stationary base, are mated to show the cooperating relationship therebetween.

FIG. 3 is a perspective, side elevational view of the outer surface of the movable plunger of the present invention showing the retaining pin and extractor extending therethrough.

DETAILED DESCRIPTION Referring now to the drawings and particularly to FIG. 1, a movable plunger generally designated 10 which may be supported to a sustaining surface (not shown) by a 'stud 12 or thread-screw, is provided with a longitudinal channel 14 within which is positioned a slideable piston 16 seated within a slightly enlarged portion 18 of the channel 14. A spring 20 biases the piston downwardly as shown, and a stop 22 extends from the side of the piston through a slot 24 in the wall of the plunger 10. A guide rod 26 is attached by any suitable means to the piston 16 and extends upwardly through channel 14 to provide and ensure aligned, slidable movement of the piston within the channel.

Plunger 10 has a lower, sloped edge 28 which is formed after a recessed lip 30 encircles the plunger a selected distance from the lower end. The sloped edge 28 forms a wedge which is engageable with the previously crimped commutator tangs, those designated 32 being representative, to raise those tangs to the position shown in FIG. 1, an operation which will be more particularly described subsequently.

A base 34 adapted to be stationarily mounted by a threaded recess 36 or the like, is designed to mate with the plunger by the provision of an annular ring 38 having sloped walls within which will nest the sloped lower edge 28 of the plunger. A hub 40 is centered within the recess to engage the center opening of the commutator such as is shown in FIG. 1, this hub serving to retain securely the commutator during the tang-raising operation.

To perform the resalvaging operation, the plunger 10 is secured to a displaceable supporting structure which could be similar to a drill press so that the entire structure can be urged downwardly selectively as needed or desired. It has been found advantageous to place a large number of variously sized tools on one structure so that a desired size can be selected by mere rotation of a table or the like placed before the operator. Once the size tool has been selected according to size of the commutator to be processed, the operator need only place the commutator within the annular recess or ring 38 of the base 34 with the hub 40 extending through the opening within the commutator and move the upper supporting structure carrying the plunger 10 downwardly to receive the commutator within the channel 14. As the plunger continues downwardly, the lower sloped edge 28 engages the crimped tangs lying substantially fiatagainst the surface of the segments 42 and wedges these elements apart. The slope s of the lower edge 28 determines the angular relationship of the tangs with the segments and is obviously variable to whatever extent desired.

When the plunger 10 and the base 34 are mated and the commutator reprocessed by the cooperating activity therebetween, piston 16 is displaced as the biasing of spring 20 is overcome. Upon release of the force urging plunger 10 into a mating relationship with the base 34, the spring 20 quickly displaces piston 16 downwardly to eject or expel the salvaged commutator which might be snug about the lower sloped edge otherwise because of the wedging action which has occurred. Thus the piston and spring form an extractor for removing the reprocessed devices expeditiously.

-An alternative embodiment of a commutator tool is shown in FIGS. 2 and 3 wherein a mating plunger 44 and base 46 cooperate to perform the operation which has been previously described. A circular rod 48 is axially disposed within a channel 50 in the plunger, and a substantially horizontal member 52 communicates with the rod 48 and extends through slots 54 in the plunger provide a stop for the mating components and .a partial extractor to dislodge a reprocessed commutator upon separation of the plunger and the base. This embodiment is the simplest in design and construction and would provide very significant results in an operation where high reprocessing production is not an immediate requirement.

It is contemplated that localized, high intensity heat may be applied at the bend in the crimped tang area as the plunger is simultaneously lowered so that all possibility of shearing or stripping of the tangs from the segments is eliminated. This technique has been found effective in crimping tang commutators because the intense heat application makes the metal, usually copper, very soft and manageable.

While there has been described a preferred and alternative embodiment of a commutator tool particularly adapted for salvaging production commutator rejects, it is to be understood that the foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as the details of the illustrated embodiments, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. A commutator tool for a commutator having a plurality of segments and tangs, said tool comprising: a plunger; a longitudinal channel within said plunger; an extractor movable within said plunger; means for moving said extractor; a commutator-supporting base matable with said plunger; and means for selectively mating and separating said plunger and base whereby a commutator supported by the base will be cooperatively received within the channel when the plunger and base are mated and the plunger will raise the commutator tangs to a predetermined position.

2. A tool as claimed in claim 1, said plunger having a lower sloped edge engageable with the commutator tangs, the slope of said lower edge determining the position to which the tangs are raised.

3. A tool as claimed in claim 1, said base having an annular ring cooperatively receiving said plunger and a commutator-retaining hub extending from said recess.

4. A tool as claimed in claim 2, said base having an annular ring cooperatively receiving said plunger and a commutator-retaining hub extending from said recess.

5. A tool as claimed in claim 1, said extractor including a circular rod axially disposed within said channel and a substantially horizontal member communicating with said rod and extending through said plunger so that the rod and member can be displaced after the plunger engages a commutator to dislodge the commutator upon separation of the plunger and the base.

6. A tool as claimed in claim 4, said extractor including a circular rod axially disposed within said channel and a substantially horizontal member communicating with said rod and extending through said plunger so that the rod and member can be displaced after the plunger engages a commutator to dislodge the commutator upon separation of the plunger and the base.

7. A tool as claimed in claim 1, said extractor including a piston guidably supported within said channel and a spring biasing said piston toward one end of said channel whereby the spring urges the piston against a commutator to dislodge the commutator from the plunger upon separation of the plunger and base.

-8. A tool as claimed in claim 4, said extractor including a piston guidably supported within said channel and a spring biasing said piston toward one end of said channel whereby the spring urges the piston against a commutator to dislodge the commutator from the plunger upon separation of the plunger and base.

9. A tool as claimed in claim 8, said piston having a guide rod extending upwardly therefrom in said channel and inducing aligned slidable movement of said piston within said channel.

10. A tool as claimed in claim 9, said recess and said hub cooperating with said plunger sloped edge to terminate matable movement of said plunger with said base at a preselected position.

References Cited UNITED STATES PATENTS 12,413,591 12/1946 Sturdy 72 3ss 2,443,185 6/1948 Erb 72-414 FOREIGN PATENTS 1,116,091 1/1956 France.

CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R. 29-597; 72-470-

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