US2507981A - Brush spring retractor - Google Patents

Description

May 16, 1950 H, KRAUSE 2,507,981

BRUSH SPRING RETRACTOR Filed March 30, 1949 Zmventor Gttornegd Patented May 16, 1950 BRUSH SPRING RETRACTOR Herbert A. Krause, Brookfield, Ill., assignor to General Motors Corporation, Detroit, Mich, a

corporation of Delaware Application March 30, 1949, Serial No. 84,427

4 Claims.

The present invention relates to retracting tools and more particularly to a retracting tool for the brush fingers of dynamoelectric machines. The principal object of the invention is to provide a compact retracting tool which is readily engageable with the various brush fingers of the brush holders located in the confined space adjacent the commutator or slip rings in dynamoelectric machines for readily retracting these fingers.

Another object is to provide releasable tool latching means engageable with a portion of the brush holder to retain the tool and brush finger engageable thereby in the retracted position in order to readily and safely replace the brushes.

The novel features of the tool by which these objects are accomplished are clearly described in the following detailed description and are illustrated in the accompanying drawings.

Figure 1 of the drawings is a side elevational view of the retracting tool shown engaged with a brush finger in the normal operative position.

Figure 2 is a view similar to Figure 1 with the tool and brush finger in the retracted position and retained in this position upon engagement of the latching means of the tool with the brush holder.

Figure 3 is an enlarged perspective view of the tool showing the specific details of the tool assembly.

As best shown in Figure 3 the brush retracting tool comprises a main lever I having a handle portion 3 at the outer end and a bifurcated inner end fulcrum portion. The two legs 5-| of the bifurcated fulcrum portion are downwardly curved at the extremities thereof. Brush finger engaging means are provided on the lever I comprising a depending U-shaped stirrup 9 secured to the lever intermediate the ends. The lever is shown provided with an upstanding side portion intermediate the ends and a latching lever I3 is pivoted intermediate its ends by means of a pivot pin 5 to this upstanding portion l of the main lever for angular movement relative thereto. The latching lever I3 is provided with an outer end handle portion I located above the handle portion 3 of the main lever and a downwardly extending hooked portion I9 is provided on the inner end of the latching lever located above the leg 5 of the bifurcated inner end fulcrum portion of the main lever I. A leaf spring 2| is secured at one end to the upper face and at one side of the main lever handle portion 3 and the other end of the spring 2| extends upwardly and engages the underside of the latching lever handle portion I 1 adjacent the pivot pin 5 to oppose angular movement of the latching lever handle portion angularly into engagement with the main lever handle portion 3 and normally retain the portion of the latching lever adjacent the hooked inner end portion 19 in contact with the leg 5 of the main lever fulcrum portion.

The above described brush finger retracting tool is shown in Figure l with the depending stirrup 9 of the main lever engaged with a hooked portion 23 of a brush finger I25 and the curved legs 5-'| of the bifurcated fulcrum positioned along opposite sides of a spring anchor lever 21 of a brush holder frame 29 of well known type secured in conventional manner to the stator of a dynamoelectric machine, not shown, adjacent the peripheral surface 3| of the commutator or slip rings, shown in dotted line, of the rotor of the machine. The spring anchor lever 21 is provided with a hub portion 33 pivoted on an insulating bushing 34 on a pin 35 supported at the ends on the brush holder frame 29. The anchor lever may be positioned angularly with respect to the bushing and held in different angular positions thereon by means of a key 36 engageable in one of a plurality of slots 31 in the hub portion 33 of the anchor lever. The key 36 is releasably secured by a machine screw 38 to the brush holder frame 29. The brush finger 25 is also pivoted on the bushing 34 by means of side bearing portions 39 spaced axially either side of the anchor lever hub portion. A brush finger spring, generally indicated at 4| having the opposite ends 43 shown hooked over the finger side bearin portions 39, adjacent helical portions 45 around the portions of the bushing 34 and an upstanding central loop portion 41 engageable with the opposite ends of a pin 49 secured in an opening in the end of the anchor lever 21 serves to urge the outer end of the finger 25 into contact with the outer end of a brush 5| slidable in a slot 53 in the brush holder frame and thereby hold the inner end of the brush in firm contact with the peripheral surface 3| of the commutator or slip ring.

The main lever l of the brush finger retracting tool is shown in Figure l in position to retract the brush finger 25. The curved legs 5-! of the bifurcated fulcrum portion of the main lever are shown engaged with the helical portions 45 of the spring and the main lever stirrup 9 is in engagement with a hooked portion 23 of the brush finger. It will be evident that clockwise movement of the main lever I from this engaged position moves the brush finger 25 clockwise away from the brush 5| against the action of the finger spring 4| and the hooked end IQ of the pivoted latching lever is positioned by the leaf spring 2! to engage the key 36 and hook over the outer end surface thereof, as shown in Figure 2, when the brush finger is fully retracted to hold the tool and finger in .the'retracted position. The leaf spring 21 serves in the same manner when the retracting tool is inverted and engaged with the brush finger in another brush holder frame positioned adjacent the diametrically opposite or lower side of the commutator 'or slip ring surface 3|.

The construction of the above described retracting tool enables brush fingers located in the limited space available in dynamoelectric machines to be easily retracted and held -in this position whereby the brushes may be :safely replaced.

.I claim:

. 1. Jin zaretracting tool .for-a spring biased brush finger pivoted in :a brush holder 'of Ta dynamo- .electric machine, a main lever, a latching lever pivoted thereon, xsaid main lever having brush finger engaging .means and a fulcrum portion .engageable with .a portion of the brush holder, said latching lever having a hooked end portion engageable .with another portion of the brush holder when "the finger is retracted by the main lever.

2. In .a retracting tool :for' aspring biased brush ifinger pivoted in a :brush holder of a "dynamofe'lectric machine, a main lever having brush finger engaging means and a fulcrum portion "contactable and movable with respect to the brush =holder, a latching lever pivoted on the 4 main lever and having a latch portion engageable with another portion of the brush holder when the main lever is moved relative to the brush holder to retract the brush finger and a spring normally urging the latching lever.

3. In a retracting tool for a spring biased brush finger pivoted in a dynamoelectric machine brush holder, a main lever having a handle portion on the outer end, a fulcrum portion on the inner end adapted to engage a portion of the brush :holder and means intermediate the ends engageable with the brush finger, a latching lever pivoted intermediate the ends on the main lever,

a hook-shaped inner end portion adapted to releasably engage a portion of the brush holder when the finger is retracted, and a spring envgageable with .the handle portions of both levers normally positioning the hook-shaped inner end portion of the latching lever for engagement with the brush holder.

.4. In a retracting .tool for a spring biased brush fingerin adynamoelectric machine brush holder,

a main lever having brush finger engaging means intermediate the ends, a bifurcated fulcrum inner end portion engageable with the brush holder either side of the fingerand an outer end handle portion, a latchin lever pivoted intermediate the ends to the main lever, a hook-shaped inner .end portion and an outer end handle portion and spring means for urging the handle portions of the mainand latching levers apart and positioning the .hookeshaped inner end ,portion of .the latching lever .into releasable latching engagement with the brush holder upon retraction of .the finger when engaged by the main lever.

HERBERT A. .KRAUSE.

No references cited.

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