US1183253A - Commutator. - Google Patents

Description

M. E. THOMPSON.

COMMUTATOR.

APPLICATION FlLED. JUNE 26,1914.

Patented May16, 1916.

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MILTON E. THOMPSON, OF RIDGEWAY, PENNSYLVANIA.

COMMUTATOR.

Specification of Letters Patent.

Patented May 16, 1916.

Application tiled June 26, 1914. Serial No. 847,376.

To all whom t may concern:

Be it known that I, MILTON E. THOMPSON, a citizen of the United States, and a resident of Ridgeway, Elk county, State of Pennsylvania, have invented new andl useful Improvements in Commutators, of which the following is a specification.

My invention rela-tes to improvements in commutators and more particularly to those of the cylindricaltype comprising conducting segments with insulating means therebetween. In assembling such commutators it is customary to provide dovetail or equivalent faces on the edges of the segments, then assemble vthe segments with the insulating means and hold them in assembled position by suitable clamping means. While so held various faces,- which are to be engaged with means for holding the segments together` in the finished commutator, are turned down or bored out in a well-known manner in order that these engaging faces will be symmetrical on all the segments. In such boring out it often happens that the metal of which the conducting segments are made will bur over from one segment toits adjacent segment, either causing a short circuit between the adjacent segments or materially cutting down the insulation there-between.

The main object of this invention is to provide an arrangement whereby these disadvantages are overcome and to this end I make the distance between the segments much thicker adjacent said bored surfaces than the insulation separa-ting the segments at their wearing portions so that at these points the distance across the insulation from one segment to its adjacent segment will be so great that any burring of the metal will not appreciably affect the insulation between the two segments. In practice I have made theseparation three times as much at the bored surfaces as at the wearing surfaces, although a somewhat lesser sepa.- ration is practicable.

A further object of my invention is to provide insulation between such commutator segments which may beconveniently and easily assembled and is not likely to get out of order.

Further objects, features and advantages will more clearly appear from the detailed description given below taken in connection with the accompanying sheet of drawings which forms a part of this specification.

In the drawings, Figure 1 is a transverse section of a portion of a commutator embodying my improvements in one form; and Fig. 2 is an end view of some of the conducting segments with intervening insulation of the commutator of Fig. 1.

Referring to the drawings 1-1 represent conducting segments arranged in the form of a cylinder with insulating means therebetween. The insulating means consists of a sheet or strip of mica material 2 between adjacent segments and separate sheets of insulating fiber 3 3 one on each side of the mica sheet 2 and extending only part way from the bottom of the segments to the tops thereof. All of the segments and insulating strips are provided with bored out or turned down faces 4, 5 and 6 forming a sort of dovetail for engagement with members 7 and 7 which hold the segments and insulation in place. The members 7 and 7 are provided with surfaces 8, 9 and 10 which oppose the surfaces 4, 5 and 6 and when the bolt 11 is tightened the members 7 and 7 are drawn together causing the surfaces 8, 9, and 10 to approach the surfaces 4, 5 and 6 and clamp the segments and insulation firmly in position. A sheet of insulating fiber 12 and of mica material 13 are interposed between the surfaces 8 and 4 and rings of mica material 14 are interposed between the surfaces 9 and 5 and 10 and 6 so that the segments 1 are thoroughly insulated from the clamping members 7 and 7.

In assembling the commutator the segments 1 and insulating sheets 2, 3 are placed in position and held in such position without the members 7 and 7 in any suitable manner. Vhile so held the surfaces 4, 5 and 6 are bored out or turned down so that all of such surfaces will be symmetrical and will properly engage the surfaces 8, 9 and 10 when clamped by the members 7 and 7.

Vhile the sheets of fiber 3, 3 have a different radial length from the sheets 2, and they only extend from the inner ends of the segments part-way toward the outer ends or periphery of the segments, nevertheless,- they extend beyond all the bored surfaces such as 4, 5 and 6 so that the insulation between two adjacent segments is materially thicker ad` jacent all bored portions of the segments than adjacent the outer portions of the segments. The segments 1 aie provided with shoulders 15 to accommodate the outer edges of the sheets 3, these shoulders being outside of the bored surfaces 6, etc. The segments 1 are provided with slots 16 for the connection of ele trical conductors thereto and on one side o the commutator the mica sheets 2 are allowed to project beyond the segments outside of the insulating ring 10 to better insulate the terminals of these conductors from one another.

As it is difficult to provide an inte al piece of mica insulation of varying thickness which will withstand the usage required, and in order to cheapen the construction without detriment thereto, the insulation between two adjacent segments l consists of a plurality of sheets of insulating material 2, 3 each of uniform thickness, the middle sheet 2 extending out between the segments to the periphery of thel commutator so that both inner and outer portions of the insulation are of uniform thickness, although, of course, the different sheets 2, 3 may be of different thickness from one another and if desired one ofthe sheets 3 may be omitted between each two segments. By having the outer ortions of the insulation of uniform thic ess the commutator may be worn down to the shoulders 15 by ordinary use without the space between the segments under the brushes increasing, and by having the insulation thicker below the shoulders 15 or adjacent the board surfaces 4, 5 and 6 there is no danger of short circuiting due to burring over o f the metal in the boring operation.

As will be seen from the drawing the insulation acts as means for maintaining the segments a substantially greater distance apart adjacent the bored surfaces than at the portions provided for wear, and each commutator section has its portions provided for wear of substantially the same thickness and its lower portions of substantially greater uniform thickness.

Although I have described my improvements in great detail and with respect to one particular embodiment thereof, I do not desire to be limited to such details except as clearly pointed out in the appended claims since many changes and modifications may well be made without departing from the spirit and scope of my invention in its broader as ects.

Having ully and clearly described my invention what I claim and desire to secure by Letters Patent, is

1. A commutator including a number of separated segments each integral throughout, which, when assembled, have a brush bearing surface and a machined surface, and insulation between the segments, said insulation being of a given uniform thickness from the bearing surface through the poi'- tion of the commutator devoted to wear and of a substantially greater thickness at and adjacent to said machined surface whereby the bored parts of adjacent segments are separated by too great a distance to enable a bur caused by turning down to substantially bridge the space between segments.

2. A cylindrical commutator including a number of separated segments each integral throughout, which, when assembled, have a brush bearing surface on the outer cylindrical surface and an inner cylindrical bored surface, and insulation between the segments, said insulation being of a given uniform thickness from said brush bearing surface through the portion of the commutator devoted to wear and of a substantially greater thickness at and adjacent to said inner bored surface whereby the bored parts of adjacent segments are separated by too great a distance to enable a bur caused by turning down to substantially bridge the space between segments.

3. A commutator comprising conducting segments with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent segments being materially thicker adjacent said bored surfaces than adjacent the outer portions of the segments, and consisting of a plurality of sheets of insulating material each of which is of uniform thickness throughout.

4. A commutator comprising separated conducting segments having a brush-bearing surface, an insulating sheet between each adjacent pair of segments extending from the brush-bearing surface to the surface opposite the brush-bearing surface and filling the space between the segments at and adjacent to their outer brush-bearing surface, and additional insulation between the se ments at and adjacent to the surface opposite the brush-bearing surface.

5. A conimutator comprising conducting segments each integral throughout with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent se ments being materially thicker adjacent said bored surfaces than adjacent the outer portions of the segments whereby said insulating means are too thick to allow a bur to substantially bridge adjacent segments, and the outer portion of the insulation being of uniform thickness.

6. A coinmutator comprising conducting segmentseach integral throughout with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent segments being materially thicker adjacent said bored surfaces than adjacent the outer' portions of the segments whereby said insulating means are too thick to allow a bur to substantially bridge adjacent segments, and both inner and outer portions of the insulation being of uniform thickness.

7. A commutator comprising conducting segments with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent segments being materially thicker adjacent said bored surfaces than adjacent the outer portions of the segments and consisting of a plurality of sheets of insulating material each of uniform thickness.

8. A commutator comprising conducting segments with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent segments being materially thicker adjacent said bored surfaces than adjacent the outer portions of the segments and consisting of a plurality of sheets of insulating material, one of said sheets extending out between the segments to the periphery of the commutator.

9. A commutator comprising conducting segments with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent segments being materially thicker adjacent said bored surfaces than adjacent the outer portion of the segments and consisting of a plurality of sheets of insulating material comprising two sheets of insulating fiber with a sheet of mica material therebetween, the mica sheet extending out between the segments to the periphery of the commutator and all of said sheets being of uniform thickness.

l0. A commutator comprising conducting segments with insulating means therebetween, the segments having bored surfaces for engagement with means to hold the segments together, the insulating means between two adjacent segments being materially thicker adjacent said bored surfaces than adjacent the outer portions -of the segments and consisting of a plurality of sheets of insulating material comprising two sheets each of uniform thickness and a third sheet of uniform thickness extending out between the segments to the periphery of the commutator.

1l. A cylindrical commutator comprising conducting segments assembled to produce a cylindrical brush-bearing surface, insulating members of even thickness between saidv segments and further insulating pieces between the first-named insulating pieces and the segments and extending only part-way from the bottoms of the segments toward the brushbearing surface of the segments.

12. A cylindrical commutator comprising conducting segments with insulating means therebetween, the distance across the outer periphery of which is greater than the distance across the inner periphery thereof, the insulating means between two adjacent segmentsconsisting of insulating members of even thickness between the conducting segments and further insulating pieces between the first-named insulating pieces and the conducting segments at the inner ends thereof.

13. A cylindrical commutator comprising conducting segments with insulating means between the segments, the insulating means between two adjacent segments consisting' of a plurality of sheets of insulating material of different lengths in a direction at right angles to the bearing surface of the commutator.

14. A cylindrical commutator comprising conducting segments with insulating means between the segments, *the insulating means between two adjacent segments consisting of a plurality of sheets of insulating material of diiferent lengths in a direction at right angles to the bearing surface of the commutator, said sheets being of uniform thickness.

l5. A cylindrical commutator comprising conducting segments each integral throughout with insulating means therebetween of uniform thickness throughout that portion of the commutator provided for wear, the segments having bored surfaces for engagement with means to hold the segments together, the distance between two adjacent segments being materially greater adjacent said bored surfaces than adjacent the outer portions of the segments, whereby when boring said surfaces the segments will not bur over from one to another to cause short circuiting of the segments.

16. In a cylindrical commutator composed of bored segments each integral throughout having insulation of uniform thickness clamped between them at the portions provided for wear and means for maintaining the opposed surfaces of adjacent segments at a substantially greater distance apart than the thickness of said insulation, where adj acent the bored surfaces whereby adjacent bored surfaces are sufficiently separated to prevent a bur from substantially bridging the space between segments.

17. A commutatorv including segments each integral throughout having insulation between each pair of segments which insula- In testimony whereof, I have signed my tion is of substantially uniform thickness at name to this specification, in the presence of 1o the portions provided or wear all?1 is of subtwo subscribing witnesses. stantially greater uni orm thic ess at its 5 lower portions whereb at said lower parts MILTON E' THOMPSON' the segments are su ciently separated to Witnesses: prevent a bur caused by turning down to EDWIN SEGER, substantially bridge the insulation. RICHARD Em

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