US3902241A

US3902241A - Method of manufacturing pressed material commutators

Info

Publication number: US3902241A
Application number: US476517A
Authority: US
Inventors: Lothar Worner; Heinz Gerlach
Original assignee: Krautt & Bux A G Fa
Current assignee: Krautt & Bux A G Fa; Krautt & Bux AG Firma
Priority date: 1973-06-06
Filing date: 1974-06-05
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02
Also published as: JPS5027905A; FR2232850B1; DE2328753A1; SE391843B; SE7407380L; FR2232850A1; GB1433987A

Abstract

A method of manufacturing pressed material commutators comprising a hollow cylindrical shaped metal body, which is provided with a number of axial oriented groups of inwardly projecting anchoring elements, the number corresponding to a predetermined number of commutator segments, whereby the metal body is pressed in a press mold with a pressed material into a commutator blank and later is divided into individual laminae, characterized in that the division of the metal body of the commutator blank is performed before the cooling of the same.

Description

United States Patent [191 Wiirner et al.

[111 3,902,241 1 Sept. 2, 1975 METHOD OF MANUFACTURING PRESSED MATERIAL COMMUTATORS [75] Inventors: Lothar Wo'rner, Stuttgart; Heinz Gerlach, Ehningen, both of Germany [73] Assignee: Firma Krautt & Bux A.G., Stuttgart,

Germany [22] Filed: June 5, 1974 211 App]. No.: 476,517

[30] Foreign Application Priority Data June 6, 1973 Germany 2328753 [52] US. Cl. 29/597; 29/418; 29/527.l; 264/139; 264/237; 264/269; 310/43; 310/235 [51] Int. Cl. HOIR 43/08 [58] Field of Search 29/597, 418, 527.1; 310/235, 236, 43; 264/139, 162, 237, 269,

[56] References Cited UNITED STATES PATENTS 1,993,966 3/1935 Kessler 29/597 2,188,423 l/l940 Andrews 29/597 2,400,590 5/ 1946 Meyerhoeffer 2,963,774 12/1960 Pike 29/597 Primary Examiner-Carl E. Hall Attorney, Agent, or Firm-Wigman & Cohen [57] ABSTRACT A method of manufacturing pressed material commutators comprising a hollow cylindrical shaped metal body, which is provided with a number of axial oriented groups of inwardly projecting anchoring elements, the number corresponding to a predetermined number of commutator segments, whereby the metal body is pressed in a press mold with a pressed material into a commutator blank and later is divided into individual laminae, characterized in that the division of the metal body of the commutator blank is performed before the cooling of the same.

2 Claims, 1 Drawing Figure METHOD OF MANUFACTURING PRESSED MATERIAIL COMMUTATORS The present invention relatesto a method of producing pressed material commutators, in general, and molded plastic commutators, in particular, comprising a hollow cylindrically shaped metal body, which is equipped with anumber, corresponding to the number of commutatorsegments, of axially aligned groups of inwardly projecting anchoring elements, whereby the metal body is pressed or molded in a press or compression mold with an insulating material to produce a commutator blank, being preferably molded from a known plastic composition, and which blank is later divided into theindividual laminae or plates.

Small commutators are frequently composed not of individual laminae, but rather of a hollow cylindrically shaped metal body, which is equipped with a number, corresponding to the number of commutator segments, of axially aligned groups of inwardly projecting anchoring elements. These metal bodies are made either from profiled copper tube, which for example has been profiled in an extrusionand drawing-process and from which the individual metal bodies are separated in corresponding appropriate lengths, or they are made from a profiled band or strip, which has been profiled from a preliminarily shaped band or from stock material by rolling by rollers, and from which, sections corresponding respectively to the peripheral length of the commutator, are cut, separated and rolled into the hollow cylindrically shaped metal bodies. By the production of commutators with hooks for the windings, the last mentioned method is more economical, since the section of the metal body, which has the twisted hooks, can be manufactured with a conservation of material with the rollers by means of a corresponding displacement of material during rolling, whereas with the use of a profiled copper tube, it must be produced from a corresponding longitudinal section of this tube by a cutting removal of material.

The hollow cylindrically shaped metal bodies are heated and pressed or filled under pressure, in a press or compression mold with a heated insulating material customary therefor, into a commutator blank, which as a rule already has the receiving bore. With these commutator blanks, the annular shaped metal body is divided into the individual laminae by sawing between the longitudinal ribs with the anchoring elements, i.e., between the groups of the anchoring elements.

During cooling of the heated and compressed commutator blank, the contraction of the insulating mate rial body is larger than that of the metal body. Thereby the insulating material body loosens or releases itself somewhat from the metal body, so that after the division of the metal body into the individual laminae, these no longer are rigidly anchored in the insulating material body. By the use of an adhesive insulating material, the danger of the loosening of the laminae is reduced, however instead there occurs in the insulating body a formation of cracks originating from the bore side of the commutator. Both occurences influence the strength, solidity and durability of the finished commutator to a considerable degree.

Accordingly it is an object and task of the present invention to provide a method of manufacturing pressed material commutators by which the above-mentioned disadvantageous occurences do not occur.

This object and task is solved by the present invention by a method with the aforementioned method steps, in which the division of the metal body of the commutator is performed before the cooling of the insulating material thereof. Accordingly, there is no longer present, during the cooling of the commutator, a metal body closed in the circumferential direction, so that, of the individual laminae which are now separated from one another, the contraction or shrinkage in the radial direction occurring during the cooling of the insulating material body can follow without any further consequences. In this manner, the loosening of the laminae and the occurrence of cracks in the insulating material body characteristic of the prior art are avoided.

Accordingly, a further object of the present invention is to provide a method of manufacturing pressed material commutators comprising a hollow cylindrically shaped metal body, which is provided with a number of axially oriented groups of inwardly projecting anchoring elements, the number corresponding to a predetermined number of commutator segments, whereby the metal body is pressed in a press mold with a pressed material into a commutator blank and later is divided into individual laminae, and characterized by the step of performing the division of the metal body of the commutator blank prior to significant cooling of the pressed material.

It is another object of the present invention to provide a method for the production of pressed material commutators in accordance with the above-mentioned objective, and further wherein the metal body of the commutator blank is suddenly cooled, chilled or quenched by a cooling means or medium prior to the subdivision into the laminae.

The last mentioned object and method therefor thus in a more advantageous manner can be yet thereby favored in that the metal body of the commutator blank is cooled suddenly, chilled or quenched prior to the division into the laminae, by means of any suitable cooling means or cooling medium known per se.

In this manner the metal body which is connected intimately in the hot pressing condition with the insulating material body is additionally shrunk-on the not suddenly cooled and therefore slower cooling insulating material body. Thus, the anchoring of the laminae, which are subsequently separated from each other, is still further improved.

For the tempering or annealing of the pressed material commutator connected in general to the division of the metal body in the individual laminae the method in accordance with the present invention likewise is of advantage, since a loosening between the laminae and the insulating material body and/or a formation of cracks in the insulating material body neither occurs nor develops, which otherwise, during tempering or annealing of the entire commutator, could worsen.

With the above and other objects in view the present invention will become further understood in connection with the following detailed description of the drawing of which the only FIGURE is a partly sectioned perspective view of a finished commutator in accordance with the present invention.

Referring now to the drawing, a finished commutator 1 is illustrated. The hollow cylindrical metal body 2 is divided into a plurality of laminae or plates 2a prior to the cooling of the same.

Each laminae is formed with a plurality of axially oriented anchoring elements 3, whereby each of the individual laminae 2a is anchored in the insulating body 4 which has a central receiving bore 5.

While we have described a preferred method of the present invention, it is to be understood that this description is not presented in any limiting sense.

We claim:

1. A method of manufacturing pressed material commutators comprising a hollow cylindrically shaped metal body, which is provided with a number of axially oriented groups of inwardly projecting anchoring elements, said number corresponding to a predetermined number of commutator segments, comprising the steps of:

molding an insulating material into an insulating body joined to and at leastpartially within said metal body in a mold under heat and pressure to form a heated commutator blank;

subsequently dividing said metal body into a plurality of individual lamina held together in spaced relationship by said insulating body, the dividing step occurring prior to any significant cooling of the insulating material; and

subsequently cooling said commutator blank after said metal body has been divided into said plurality of individual lamina.

2. The method of manufacturing pressed material commutators, in accordance with claim 1, further comprising the step of:

suddenly rapidly cooling, by a cooling medium, said metal body of said commutator blank prior to the step of dividing said metal body into said plurality of individual lamina.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3, 902, 241 DATED September 2, 1975 INVENTOR(S) 1 Lothar Worner and Heinz Gerlach It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the patent, please change the number of the German Foreign Priority Application to --P 23 28 753. 8- rather than "23287. 53".

Please change the assignee's name from "Firma Krautt & Bux A-G." to Firma Kautt & Bux KG.

Signed and Scaled this A nest:

RUTH. C. MAISON I C. MARSHALL DANN 8 m Commissioner ofParenl: and Trademark:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN PATENT NO. 3, 902, 241 DATED September 2, 1975 INVENTOR(S) Lothar Worner and Heinz Gerlach It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the patent, please change the number of the German Foreign Priority Application to P 23 28 753. 8-- rather than 23287. 53".

Please change the assignee's name from "Firma Krautt & Bux A-G." to Firma Kautt & Bux KG,

-Thirteenth Day 0? July 1976 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofPaIents and Trademarks

Claims

1. A method of manufacturing pressed material commutators comprising a hollow cylindrically shaped metal body, which is provided with a number of axially oriented groups of inwardly projecting anchoring elements, said number corresponding to a predetermined number of commutator segments, comprising the steps of: molding an insulating material into an insulating body joined to and at least partially within said metal body in a mold under heat and pressure to form a heated commutator blank; subsequently dividing said metal body into a plurality of individual lamina held together in spaced relationship by said insulating body, the dividing step occurring prior to any significant cooling of the insulating material; and subsequently cooling said commutator blank after said metal body has been divided into said plurality of individual lamina.

2. The method of manufacturing pressed material commutators, in accordance with claim 1, further comprising the step of: suddenly rapidly cooling, by a cooling medium, said metal body of said commutator blank prior to the step of dividing said metal body into said plurality of individual lamina.