US3176396A - Coil stripping chisel - Google Patents

Description

April 6, 1965 P. STRAKA 3,175,396

COIL STRIPPING CHISEL Filed June 14, 1963 INVENTOR WhY/f {kW h, pd/h [Zr/1r United States Patent O 3,176,396 COIL STRIPPIN G CHISEL Philip Straka, Portland, reg., assignor to Crown Indus- This invention relates to a coil stripping chisel of the type used to cut the coils of an electric motor.

One purpose of the invention is a coil stripping chisel I of the type described which will cut the motor coils without scarring or otherwise damaging the motor laminations.

Another purpose is a chisel of the type described, the cutting edge of which is shaped to bunch the wires in a coil so that they may be more easily cut.

Another purpose is a coil stripping chisel in which the cutting edge is protected from dulling.

Another purpose is a coil stripping chisel of the type described which is so formed that it may be inserted down below the edge of a motor casing to cut the coils.

Another purpose is a chisel of the type described which is so formed that it will not damage the motor casing.

Other purposes will appear in the ensuing specification, drawings and claim.

The invention is illustrated diagrammatically in the following drawings wherein:

FIGURE 1 is a side view of the lower end of a coil stripping chisel,

FIGURE 2 is a top plan view of a portion of the chisel shown in FIGURE 1,

FIGURE 3 is a top plan view of a motor illustrating the operation or use of the chisel shown in FIGURES 1 and 2, and

' FIGURE 4 is a section along plane 4-4 of FIGURE 3.

The chisel may include a shank which may be formed either for use with a hand tool, such as a hammer, or for use with an air hammer or the like. The particular configuration of the shank is not important. At the end of the shank 10 is a working end indicated generally at 12 which gradually merges into the shank 10, as indicated by the curved surfaces 14 and 16. The width of the working end section, as indicated in FIGURE 2, is generally the same as the width of the shank, although this may vary depending upon the type of shank. The end section 12 may have an upper fiat surface 18 and a lower surface 20, with these surfaces gradually coming together or tapering toward a blunted end 22. As clearly shown in FIGURE 1, the blunted end 22 is rounded, as at 24, so

that there will be no sharp point or edges for scarring the motor laminations or side of the motor casing.

A crescent-shaped recess 26 may be formed at the end of the tool and may include a crescent-shaped lower cutting edge 28 and an upper crescent-shaped edge 30,

, there being a slanted crescent-shaped surface 32 connecting the upper and lower crescent-shaped edges. ,As shown in FIGURE 1, the slanted surface 32 forms an angle with the upper flat surface 18.

Considering FIGURES 3 and 4, a typical electric motor is indicated generally at 34, the stator of which may include a stack of laminations 36 with a plurality of coils 38 extending down through openings 40 in the laminations. The motor casing 42 extends upwardly beyond the upper edge of the laminations.

In operation, the chisel will be placed, as indicated particularly in FIGURE 4, with its crescent-shaped lower cutting edge 28 against the wires coming from a particular opening 40 in the laminations. Note that the chisel extends across the motor casing and is effective to cut coils at the side of the stator opposite that of the workman. As most motor casings extend upwardly beyond the laminations, as indicated in FIGURE 4, it is necessary for the working end of the chisel and the shank to form an obtuse angle or an angle such that the chisel may get down below the motor casing to work on the coils.

Of importance is the fact that the lower surface 20 of the end section 12 is generally flat. The surface must be fiat in order for the chisel to slide along the laminations and cleanly cut the coils close to the laminations. Also of importance is the fact that the end of the chisel is blunted and has lower rounded edges. This is done so that there will be no scarring of the laminations as the chisel slides over them. It is of course important that the laminations remain untouched if the motor is to be rewired and reused. Also, the blunted edges will prevent the motor casing from being cut.

It is important that the surface 32 be slanted or formed at an angle with the surface 18 to pull the chisel down tight against the laminations. The wires being cut exert a downward force on the slanted surface and tend to hold the chisel tight against the laminations for a clean cut.

The cutting edge 28 is crescent-shaped for a particular reason. As the tool moves into a group of wires, the crescent-shaped recess will tend to bunch the wires and to form a somewhat solid bar or rod out of them, as they could move about. By bunching the wires with the crescent-shaped recess, it is possible to cut a greater number of wires in one cut.

The crescent-shaped cutting edge is important in that I it keeps the cutting edge away from the end of the chisel and there is no possibility of dulling the cutting edge when the chisel strikes the side of a motor casing. This also prevents the motor casing from being scarred by the chisel.

Whereas the preferred form of the invention has been shown and described herein, it should be realized that there are many modifications, substitutions and alterations thereto within the scope of the following claim.

I claim:

A coil stripping chisel including a shank and an integral working end section forming an obtuse angle therewith, said end section gradually merging and curving into said shank and tapering from a thickness approximating that of the shank down to a rounded, blunted, relatively thin end, the top and bottom surfaces of said end section being generally flat with said fiat surfaces merging into said thin, rounded, blunted end, a crescent-shaped recess in said end forming a lower crescent-shaped cutting edge in said bottom flat surface, the upper edge of said crescentshaped recess extending further from said blunted end than said lower cutting edge, with a crescent-shaped slanted surface being formed between said upper and lower crescent shaped edges, said slanted surface forming an angle with the upper flat surface of the working end section, said crescent-shaped recess extending inwardly from said blunted end to define a pair of spaced rounded blunted ends adapted to be pushed against the side of a motor casing or the like.

References Cited by the Examiner UNITED STATES PATENTS 1,404,650 1/ 22 Richard -24 2,757,452 8/56 Barnes 30-168 2,960,767 11/ 60 Vonhofi' et a1 30-168 X FOREIGN PATENTS 110,565 5/00 Germany. 208,017 3/60 Austria.

WILLIAM FELDMAN, Primary Examiner. MILTON S. MEHR, Examiner.

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