US1769786A - Dynamo-electric machine - Google Patents

Description

y 1, 1930. v J. D. KARLE 1,769,786

DYNAMO ELECTR IC MACHINE Filed June so 928 '2 Sheets-Sheet 1 mam Cot km 17. [farl y 1930- X J. D. KARLE 1,769,786

DYNAMO ELECTRI C MACHINE Filed June so, '1928 2 sheets-sneak f2 mmmmwm Patented July 1, 1930 UNITED STATES PATENT OFFICE JOHN D. KARLE, OF ROSELLE PARK, NEW JERSEY, ASSIGNOR TO DIEHL MANUFAC- TURINGCOMPANY, OI ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY DYNAMO-ELECTRIC MACHINE Application filed June so, 1928. Serial No. 289,384.

This invention relates to dynamo-electric machines, more particularly of the singlephase motor type having a commutator, with short-circuited brushes and a speed-responsive commutator short-circuiting mechanism, adapting the motor forrepulsion operation in starting and induction operation after a predetermined speed has been attained.

An object of the invention is to provide simplified and efiicient mechanism for lifting the brushes from the commutator, after the motor has been started, to avoid unnecessary brush-wear.

Another object of the invention is to pro vide for quietness and freedom from wear of the parts when the motor is running. A further object of the invention is to rovide a brush-lifting mechanism having minimum wearing pressures upon the relatively rotating parts in starting, thus increasing the useful life of the arts.

According to t e resent improvement there isprovided a rush-lifting member which is adapted to exert a yielding pressure in one direction only from a position of rest, in which direction it engages and lifts the brush. The speed-responsive commutator short-circuiting means is arranged to govern or initiate the movement of said member from its position of rest. Due to this arrangement, the action of the speed-responsive mechanism is not opposed at any time by the brush-lifting operation and, consequently, the speed-responsive device has to press but li htly and momentarily against the brush-1i ting mechanism, to trip the latter into action.

In the present case there are presented claims which are specific to the modification shown in Fig. 6 of m copending application Serial N 0. 289,383, fi ed herewith.

In the accompanying drawings, Fig. 1 is a longitudinal sectional view of an electric motor embodying the invention; the parts of the brush-lifting mechanism being in starting position. Fig. 2 is a similar view of the brush-lifting elements of Fig. 1 in running position. Fig. 3 is an end view of the motor with the parts in starting position. Fig. 4

is a longitudinal section on the line 44, Fig. 1, and Fig. 5 is a disassembled perspective view of theremovable brush. and brushshank elements ofFig. 4.

According to the preferred embodiment of the invention illustrated, 1 represents the motor frame, 2 the field, 3 the armature and 4the commutator carried by the motor-shaft 5. Fixed to the shaft 5 is a thick disk or ring 6 having radially disposed cylindrical slideways 7 for the cylindrical weights 8 having conical outer ends 9. Slidably mounted on the shaft 5, between the ring 6 and the commutator 4 is the disk 10 which is dished to provide a conical portion 11 overhanging the conical outer ends of the weights 8. The disk 10 is also formed with a flat rim 12 disposed in a plane normal to the shaft 5. i The disk 10 is urged by the spring I 13 toward the ring 6 and, when the motor'is.

at rest, the disk 10 engages the narrow raised ring-shaped seat 14 on the ring 6, closely adj acentthe shaft 5.

Fixed to the disk 10 are. studs 15 which pass throu h apertures in the commutator short-circuiting disk 16, and are surrounded by springs 17 disposed between the disks 10 and 16 and yieldingly urging the disk 16 into engagement with the heads 18 of said studs. The disk 16 is of the usual radially slotted construction enabling it to bear upon the ends of the commutator segments and efiectively short-circuit the latter when pressed thereagainst by the action of the centrifugal Weights 8 upon the conical portion ll of the disk 10. p

The end-bonnet 1 of the motor-frame 1 is formed with a pair of bosses 19 each of which is bored radially of the commutator 4 to receive a brush-tube bushing 20 in which is fixed a brush-tube 21 on the lower end of which is clamped a terminal lug band 22 for the usual brush short-circuiting connection 23. Slidablymounted in each brush-tube 21 Disposed within the brush-tube 21 is the brush-spring 27 which at its inner end is connected to the brush 25 and at its outer end presses the terminal washer 28 of the brush pig-tail 29 against the cap-screw 30 which is threaded into and closes the outer end of the brush-tube 21. A pin-screw 31, threaded into the boss 19 and passing through the bushing 20 and brush-tube 21, enters a longitudinal slot 32 in the brush-shank 24. This pin fixes the bushing 20 and brush-tube 21 in the boss 19 and permits the brush-shank 24 to freely perform an endwise sliding movement, without rotation. The slot 32 is open at its inner end to permit withdrawal of the brush from the brush-tube 21. At the outer end of the slot 32 there is a shoulder 33 which is adapt ed to engage the Jin-screw 31, when the brush 25 has worn sunciently, and prevent the inner end of the brush-shank 24 from scraping the commutator. The brush-shank 24 is also formed with a shoulder 34 for engagement by the brush-lifting lever 35 which is fulcrumed at 36 on the ear 37 extending inwardly from the boss 19.

The brush-lifting lever 35 is formed with a short arm 38 which terminates within range of the rim 12 of the disk 10. A spring 39 coiled about the screw 36 and anchored at its opposite ends to said screw and the lever 35, respectively, urges the lever 35 in a direction to engage the shoulder 34 and lift the brush 25. Fulcrumed at 40 on the ear 37 is the spring-pressed latch-lever 41 having a shoulder 42 which is engaged by the pin 43 on the lever 35 and detains the lever 35 in starting position, Fig. 1, until the disk 10 is moved sufliciently by the centrifugal weights 8 to carry the disk 16 into short-circuiting engagement with the commutator. After shortcireuiting is effected, further movement of the disk 10 in compressing the springs 17 and 13, releases the shoulder 42 of the latch 41 from the pin 43, thus permitting the spring 39 to swing the lever 35 to lift the brush, as shown in Fig. 4. In the running position of the parts, Fig. 4, there is maintained a gap between the lever arm 38 and latch lever 41, in which gap the rim 12 of disk 10 floats without touching either lever.

IVhen the motor is slowing down preparatory to stopping, the recovery spring 13 moves the disk 11 toward the disk 6. The rim 12 of the disk 10, in this movement, engages the arm 38 of the lever 35 and resets the latter in starting position, Fig. 1, with the shoulder 42 of the latch-lever 41 in latching position over the pin 43; a slight gap being preferably provided between the shoulder 42 and pin 43 to insure certainty of operation.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a dynamo-electric machine, rotary current-carrying means, a brush yieldingly engaging said means, a springactuated brush-lifter, a latch for detaining said brushlifter in starting posit-ion against the full brushdifting power stored in the brushlifter spring, and speed-responsive means for tripping said latch.

2. In a dynamo-electric machine, rotary current-carrying means, a brush yieldingly engaging said means, a brush-lifter, a latch for detaining the brush-lifter in starting po sition against the full brush-lifting power stored in the brush-lifter spring, and speedresponsive means adapted to trip said latch, said speed-responsive means including a recovery-spring operating when the machine is slowing down to re-set said brush-lifter in starting position.

3. In an electric-motor, an armature having a commutator, a brush yieldingly engaging the commutator, a spring-actuated brushlifter, a latch for detaining said brush-lifter in starting position against the full brushlifting power stored in the brush-lifter spring, and speed-responsive commutator short-circuiting means timed to trip said latch after the short-circuiting of the commutator is eflected.

4. In an electric-motor, an armature having a shaft and a commutator, a brush yieldingly engaging the commutator, a springactuated brush-lifting lever including an arm extending toward the armature shaft, a latch-lever for detaining said brush-lifting lever in starting position with power stored in the brush-lifter spring, said latchlever including an arm extending toward the armature shaft and spaced from said brushlifting lever-arm in a direction toward said commutator, and speed-responsive commutator short-circuiting means including a disk running with the armature shaft and movable toward and away from the commutator, said disk having a rim disposed between said arms.

In testimony whereof, I have signed my name to this specification.

JOHN D. KARLE.

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