US757991A - Reciprocating electric motor. - Google Patents

Description

PATENTED APR. 19, 1904..

APPLIOATION FILED MAR.16, 1903.

N0 MODEL.

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NW NN. Q L1 1% .C .C QM GC@ .N H 1|! IIMII w NWI im. imm .HHN l| E Patented April 19, 1904.

ADOLPH F. CHRISTMAS, OF PITTSBURG, PENNSYIVANIA, ASSIGNOR AOF TWO-THIRDS TO` FRANK R. MCFEA'ITERS,

PENNSYLVANIA.

i OF WILKINSBURG,

RECIPROCATING ELEQTFuc -M01-on.

SPECIFICATION forming part of Lettersl Patent No. 757,991, dated Aiprl 19,1904.

l Application filed m8101116, 1903. Serial N0. 148,009. (N0 model.)

lo all whom, it may concern,.-

lBe it known that I, AnoLPH F. OHRIs'rMAs,

a resident of Pittsburg, in the county of Alleghen y and State of Pennsylvania, have invented a new and useful Improvement in Reciprocating Electric Motors; and I do hereby declarethe following to be a full, clear, and eX- act description thereof.

My invention relates to reciprocating electric motors; and its object is to provide a motor of this' type adapted for use with alternating currents and so constructed and arranged that sparking on the breaking of the circuit is very largely reduced.

A further object of my invention' is to provide simple and efiicient means for cooling reciprocating electric motors, and especially such as operate at high speeds.

One difficulty in adapting reciprocating electric motors to alternating currents has been due to the extensive sparking that takes place at the terminals when the circuit is broken. i A further diiiiculty has arisen from the fact that such motors usually heat excess ively, thus cutting down the current passing through the magnet-coils and making it necessary to frequently stop the same in order to permit them to cool.

The objectlof my invention is to provide a reciprocating electric motor adapted for use with alternating currents wherein both, and especially the first, of the above defects in prior motors are overcome.

'lo this end the invention consists, primarily, in so arranging the parts of the motor that the current through the coil is interrupted at the moment of greatest self-induction, thus reducing the spark at the terminals to a minimum.

'lhe invention also consists in providing the magnet coil or coils of the motor with ventilating duets or passages and connecting to the reciprocating armature a piston moving in a cylinder and so arranged with reference toy the ventilating-ducts as to circulate air through said Ventilating-duets, thus keeping the motor cool.

1n the accompanying drawings, Figurel is a longitudinal section through my improved motor, showing the same applied to a reciprocating hammer; and Fig. 2 is a detail view showing the circuit broken.

In the drawings the motor is shown applied to.. an ordinary reciprocating hammer; but it will be understood that this is for purposes of illustration merely, as the motor can be applied to any use where a reciprocating electric motor is desirable or advantageous. The motor itself comprises the electromagnet-eoil l, which preferably is hollow, as shown, and having coperating therewith the armature or core 2. The arrangement isfsueh that normally the core 2 is partially drawn out of the coil, so that the energization of said coil will draw the core into the same in the well-understood mode of operation of electromagnets. c

It is this inward movement of the core that performs the work, and when applied to a hammer such as shown the tool-shank 3 is placed in such position that it `will be struck by the end of the core 2 at or near the limit of the inward movement of the latter. `Suitable means will be provided for withdrawing the core, the means shown in the drawings comprising a spiral spring 4, interposed between the end of the magnet-coil 1 and apiston or head 5, formed on the outer end of the core. As long as the magnet is not energized the spring 4L will hold the core in the position shown in Fig. l; but as soon as current is supplied to the coil 1 the core 2 will be drawn inwardly and strike the tool-shank 3 a sharp blow. yBefore the core 2 can be again withdrawn it is necessary to break the circuit to the coil l in order to denergize the same, and it is in the arrangement for doing this that my invention principally consists.

It is Well known that a current circulating around an iron core has a much greater seltinduction than one without an iron core, this being due to the fact that the former has a `more intense magnetic iield through said iron core.

current passing through the coil 1 will be Consequently the self-induction of the greatest when the core 2 is fully drawn into said coil-that is, when the iron mass composed of thecore 2 and other parts is posi- -tioned symmetrically with reference to the coil dr when the air-gap between the movable core and the stationary iron parts is reduced to zero--and it is also then that the current practically ceases to do any work. At the moment of greatest self-induction the current passing through the coil is correspondingly decreased in strength, and consequently if the circuit be broken at that moment the spark at the circuit-terminals will be reduced to the minimum. My motor is so arranged that the circuit is broken at the moment of greatest self-induction. Various arrangements may be employed for accomplishing this purpose, and in the drawings 1 have shown one arrangement therefor which is simple and ettieient Ars shown, one of the circuit-wires,

such asV 6, has placed therein suitable terminals 7 and 8, which are shown as spring-iingers so arranged that normally they will spring apart, as shown in Fig. 2, to 'keep the circuit open. ln suitable juxtaposition with reference to the terminal 8 is pivoted a closing-arm 9, which when brought to the position shown in llig. 1 crowds the spring-linger 8 into contact with the finger 7 to close the circuit., but which when brought to the inclined position shown in Fig. 2 permits the said terminals tospring apart, thus breaking i the circuit.

the moment when said core contacts with the hammer-shank. Consequently 1 attach to the core 2 an extension 10, having thereon two shoulders or collars 11 'and 12. The collar 11 is at the outer end of said extension and in such a position that when the core 2 has almost reached the tool-shank 3 said collar will contact with the arm 9, and by the further inward movement of the core said collar will draw the arm 9 to thev inclined position shown in Fig. 2, thus permitting the terminals 7 and 8 to break the circuit,and this will occur at the moment when the core 2 practically touches the tool-shank 8 or other stationary part of the magnet, and consequently at the moment of greatest self-induction of said electromagnet. This immediately denergizes the magnet, and the spring a retracts the core 2, and in its outward movement the collar 12 comes against the circuit-closing arm 9 and moves it back -to the position shown in Fig. 1, thus again closing the circuit, so that said core will again be immediately drawn into the coil. lin this manner a continuous and very rapid reciprocation of the core 2 is obtained; but the netism across the base of the coil.

sparking at the terminals 7 and 8 is reduced to a minimum. A suitable circuit-closer, such as the button 13, operating in conjunction with terminals 14, will be employed for placing the motor in operation. Any other circuit-closer, however, would serve this purpose equally as well.

At each end of the magnet is an iron mass i represented by the castings 15 and 16, formi ing a part of the motor-casing, and the coil 1 is provided with an outer casing 17 and inner tube 18, both of which are of brass or other non-magnetizable metal and provided with slots, thus forming effective magnetic shields and preventing leakage of the lines of mag- As a result the lines of force must pass from one iron end 15 to the other iron end 16 and practically axially of' the magnet-coil, thus giving the maximum energy acting to draw the core into the coil.

In order to keep the motor cool, I provide the coil thereof with a series of passages or ducts 19. 'llhe outer end or' these ducts communicate with the atmosphere through ports 20, and the inner end thereof communicate and thehead 5 on the core 2 is practically a` piston moving in said cylinder. As a consequenee when the spring 4 moves thc core 2 outwardly the piston 5 will draw air through the ducts 19 into the chamber 21. and when said core 2 moves inwardly on the energization of the magnet said piston forces the air in the chamber 21 through the ducts 19 into the atmosphere. As a consequence during the reciprocation of the core 2 air is circulated through the ducts 19, thus thoroughly ventilating the same and preventing excessive heating. By providing simple valves the piston 5 may be made to circulate the air always in one direction, and in actual use this arrangement is preferred to the one shown in the drawings; but the latter was selected for illustration by reason of its simplicity.

The operation of my motor will bc readily understood from the foregoing description. rlhe motor will be placed in any convenient circuit supplied with an alternating current from any suitable source of power, such as the alternating generator 25. As long as the circuit-terminals 14 are kept' closed the core 2 will automatically reciprocate back and forth., being drawn into the magnet-coil by the energization of the latter and withdrawntherefrom by the spring 4 when the circuit through thc coil is broken by the head 11' on the core extension coming into contact with the circuitbreaker 9. This. as above explained, occurs kat the moment of greatest self-induction, and

as a consequence the sparking at the terminals 1s largely reduced. Furthermore, the circuitbreaking means 1s 1n no way dependent on non-synchronous means for breaking said circuit at themoment of greatest 'self-induction of the current. A

2. A reciprocating electric motor adapted for alternating currents comprising a magnetcoil, a core therefor, a circuit for saidcoil, and non-synchronous means for breaking said circuit at the moment of greatest self-induction of the coil.

3. A reciprocating electric motor adapted for alternating currents comprising a magnetcoil, a core therefor, a circuit for said coil, and non-synchronous means actuated by the core for breaking said circuit when said core has reached such position in the coil that the iron mass is symmetrically arranged with reference to said coil.

4. A reciprocating electric motor adapted for alternating currents comprising a single magnet-coil, a core therefor, a circuit for said coil', a circuit-breaker in said circuit, and a shoulder on said core arranged to contact with said circuit-breaker and open the circuit when the core contacts with a stationary part of the motor.y l

5. A reciprocating electric motor adapted for alternating currents comprising a magnetcoil, a reciprocating armature coperating therewith, a circuit for said coil, non-synchronous means for breaking the circuit at the moment of greatest self-induction of the current, and mechanical means for withdrawing said armature.- y

- 6. A reciprocating electric motor adapted for alternating currents comprising a magnetcoil, a core therefor, a circuit for said coil, non-synchronous means forbreakingsaid circuit when the core contacts with a metallic l portion of the device, and a spring for Withdrawing said core.

7. A reciprocating electric motor adapted for alternating currents comprising a single magnet-coil, a core' therefor, a circuit for said coil, a spring for withdrawing said core, acircuit-breaker, and means on said core for actuating said circuit-breaker when said core is fully drawn into said coil and for making said circuit when the core reaches the limit of its outward movement.

8. A reciprocating Velectric motor adapted for alternating currents comprising a single magnet-coil, a core therefor, a circuit for said f coil, a spring for'withdrawing said core, terminals in said circuit adaptedl normally to open, aA circuit-closing finger arranged to close said terminals, and means carried by said core and arranged'to engage said finger and alternately cause the same to open and close said I terminals. x

9. A reciprocating electric motor adapted 4for alternating currents comprising a magnetcoil, a casing therefor provided with a cylindrical extension at one end, a reciprocating armature coperating with said coil, ventilating ducts or passages through said magnetcoil, and a piston carried by said .armature and working in said casing extension and arranged to cause a circulation of air through said ducts. v

10. A -reciprocating-electric motor adapted for alternating currents comprising a magnetcoil provided with Ventilating-ducts, acasi-ng therefor provided with a cylindrical extension at one end, a core for `said coil, a spring for retracting said core, a piston carried by said core and workingin said casing extension and arranged to cause a circulation of` air through said ducts, and a circuit-breaker arranged to break the circuit when said core is fully drawn into said coil l1. A. reciprocating electric motor adapted foralternating currents comprising a magnetcoil, a sleeve'of non-magnetizable metal for said coil, an iron mass at each end of said coil, a core for said coil, and means for breaking the circuit to said coil.

ln testimony whereof I, the said ADOLPH F. CHRISTMAS, have hereunto set my hand.

AnoLPH F. CHRISTMAS.

Witnesses:

MARGARET C. KEEBLE, G. C. RAYMOND.

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