US3428843A - Commutator termination - Google Patents

Description

Feb. 18, 1969 J. R. KELLER COMMUTATOR TERMINATION Filed Oct. 15, 1965 United States Patent 3,428,843 COMMUTATOR TERMINATION Joseph Richard Keller, Harrisburg, Pa., assignor to AMP I Incorporated, Harrisburg, Pa. Filed Oct. 13, 1965, Ser. No. 495,417 US. Cl. 310-234 Int. Cl. H01r 39/32 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the art of commutators and more particularly to a new and improved means for connecting commutator leads to the metallic segments of a commutator.

At the present time there are numerous methods for connecting the leads from an armature winding to a commutator. The usual method is to effect the connection by soldering the lead to the commutator. This method has the disadvantages that the leads must be stripped prior to soldering and aluminum leads cannot normally be used. Also, there is extreme heat generated during the rotation of the armature and commutator with the result that the solder often melts and the leads will become disengaged from the commutator due to the centrifugal force set up by the rotation.

To avoid this problem it has been suggested to effect the connection without solder by mechanically deforming a portion of the metallic segments of the commutator whereby these portions will surround the leads to provide a mechanical and electrical connection. Examples of this method are found in US. Patents Nos. 2,476,795 and 2,572,956. Although this method is an improvement over the soldering method there are still serious drawbacks. One drawback is that it is expensive and time consuming to machine the metallic segments to provide the necessary slots for receiving the leads. Also, there is no real assurance that there will be an electrical connection if the leads are not stripped, this being the result of attempting to deform a large mass of metal around a comparatively small lead.

It is therefore an object of the present invention to provide a connection which avoids the above drawbacks.

Another object is to provide a commutator which is simple and inexpensive to produce.

A further object is to provide an improved means and method for connecting the leads to a commutator by simple crimping tools.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purpose of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings, in which like reference numerals refer to like parts:

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FIGURE 1 is a fragmentary perspective view of the commutator assembly;

FIGURE 2 is a front elevational view of the commutator in position to be crimped; and

FIGURE 3 is a side elevational view of the commutator of FIGURE 1.

The commutator of the present invention is shown generally at 10 and comprises an annular portion 12 in the form of a cylinder having a central opening 14 for reception of the shaft of an armature. A hub-like portion 16 is formed integrally with portion -12 and has a plurality of radial arms 18 extending therefrom, each said arm terminating at its distal end in a concave surface 20. A plurality of openings 22 are uniformly arranged in hub 16 with the openings 22 bearing a predetermined relationship to the arms 18. The parts above described are made of a dielectric material such as phenol or mica so that they are nonconductive.

A plurality of metallic commutator segments are indicated generally at 24, only one being shown in FIG- URE 1 for ease of illustration, and comprise a base portion 26 having a raised lance 28 therein and a plurality of legs 30 which may be bent downwardly and at an angle so as to provide a firm mechanical connection with the annular portion 12. The segments 24 further comprise a barrel portion 32 of open U-shaped configuration, the barrel having a plurality of serrations 34 on the inside surface thereof.

The segments 24 may be secured to cylinder 12 by any suitable means but it is found desirable to mold them into place. This is accomplished by providing the seg ments in strip form and placing the strip in a suitable mold and thereafter injecting the dielectric material into the mold to form the cylinder 12, hub 16, and arms 18 and at the same time the segments 24 will be retained by the dielectric material flowing around the legs 30. The portions of the strip connecting the individual segments would then be removed so that the segments are not in electrical communication with each other.

A commutator lead 36 is shown and extends from an armature winding. The lead is passed through barrel 32, wrapped around lance 28, and passed again through barrel 32 whereby the lead is in a position to be secured to the commutator. A pair of crimping dies 38 and 40 are shown and are disposed apart. Suitable means, not shown, may be provided on the crimping apparatus for insertion into the openings 22 to thereby position the commutator relative to the crimping apparatus. The connection is effected by advancing die 38 into contact with barrel 32 whereby the latter will be bent over into gripping engagement with the lead 36. Also, the serrations 34 will penetrate the insulation on lead 36 to insure electrical communication between the lead and the segment 24. The radial arms 18 serve as the back up or anvil for the crimping operation with the concave surface 20 aiding in the forming of the barrel. By using a dielectric anvil there is a considerable savings in cost as compared to using a larger metallic segment, which segment is normally copper. The force exerted during the crimping operation may be quite large and it is therefore desirable, although not essential, that the two dies 38 and '40 be operated simultaneously so that the forces will be opposed and will tend to cancel.

It is to be noted that the crimping force may be sufficient on occasion to crack the arms 18. However, this would not be harmful to the commutator because once the barrel overlying a particular arm is crimped, the arm no longer has any utility so its cracking or breaking is of no consequence.

It can thus be seen that the objects of the invention have been achieved and a simple and inexpensive commutator has been produced which can be quickly and easily connected to the leads of an armature Winding.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

What is claimed is:

1. In a commutator, a non-metallic member comprising a first generally cylindrical portion having a central opening for receiving an armature shaft, and a second portion integral with said first portion and comprising a hub having a plurality of radial arms extending therefrom.

2. The member of claim 1 wherein said arms are equi-distantly arranged about said hub and wherein said arms terminate in a concave surface along their outer ends.

3. The member of claim 2 further comprising a series of openings disposed in said hub portion, there being one such opening for each of said radial arms.

4. A commutator element comprising a first nonmetallic member, said member having an annular portion and a hub-like portion, a plurality of raidal arms extending from said hub-like portion, a series of metallic segments disposed about the periphery of said non-metallic member and secured thereto, said segments being aligned with said radial arms, each said segment comprising a commutator lead receiving portion overlying one of said radial arms.

5. A commutator comprising an electrical insulating member, said member having an annular portion and a hub portion, a plurality of radial arms extending from said hub portion, each said arm having an outer concave surface adjacent the outer surface of said annular portion, and a plurality of metallic segments disposed around the periphery of said insulating member in alignment with said radial arms, each said segment being out of contact with the segments adjacent thereto, said segments having a first portion secured to the annular portion of the insulating member and having a second portion overlying the concave surface of said radial arms, said segment second portion comprising a barrel having a plurality of serrations on the internal surface thereof, a lance formed in said segment first portion whereby a commutator lead, which passes through said barrel, around said lance, and back through said barrel, is connected to said commutator by closing said barrel around said lead with the barrel serrations piercing the insulation on said leads and contacting the conductive wires of said leads, said radial arms acting as back up means for the closing operation on said barrels.

6. For use in a commutator assembly of an armature, an integral member of insulating material comprising a generally cylindrical portion having a central opening to receive an armature shaft, said portion having commutator segment stations on its outer surface, and a hub coaxial with said portion and having anvil elements associated with said stations and arranged to support crimpable extensions of said segments.

References Cited UNITED STATES PATENTS 1,881,341 10/ 1932 Apple 3'10235 X 2,476,795 7/ 1949 Avigdor 310-23-3 3,080,615 3/ 1963 Carlson 29-597 X FOREIGN PATENTS 942,026 11/ 1963 Great Britain.

J D MILLER, Primary Examiner.

G. NUNEZ, Assistant Examiner.

US. Cl. X.R.

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