US568570A

US568570A - Brake mechanism for electric elevators

Info

Publication number: US568570A
Authority: US
Publication date: 1896-09-29
Anticipated expiration: 1913-09-29

Description

(No Model.)

P. E. HERDMAN. BRAKE MECHANISM FOR ELECTRIC ELEVATORS.

No. 568,570. Patented Sept. 29, 1896.

Witnesses.

Inventor.

M g mm Attorney.

UNITED STATES PATENT OFFICE.

FRANK E. HERDMAN, OF WINNETKA, ILLINOIS.

BRAKE MECHANISM FOR ELECTRIC ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 568,570, dated September 29, 1896.

Application flled October 1895- To all whom it may concern:

Be it known that I, FRANK E. HERDMAN, a citizen of the United States, residin at Winnetka, county ofCook, and State 0 Illinois, have invented a new and useful Improvement in Brake Mechanism for Electric Elevators,of which the following is a full, clear, and exact description, reference beinghad'to the accompanying drawing, which forms a part of this specification.

The brake used in my invention is a friction-brake, and, as is known, the time in making a stop with a frictional brake is proportional to the speed and load. If the car he descending and the velocity or load is great, it takes more time to bring the mechanism to rest, while, on the other hand, if the velocity be less or the load light the stop is made much quicker. 'The purpose of this invention is to obviate this and to make the ap-' plication of the brake varyas the conditions of speed and load vary, so as to make the stop constant.

I will first describe the construction as illustrated in the drawing and then particularly point out the invention in the claims.

In the accompanying drawing the figure shows a diagram maticalview of my'invention.

E is an electric motor, of which e is its shaft.

200 is a reversing-switch controlling the admission and direction of current passing to 1 the motor. This switch 200 has the hubsa a a, which hubs are all connected with the operating-shaft, but the hub a-is separated from the hub a by the insulation a and the hub a is separated from the hub a by insulation a the hub a being of conductive material. To the hub a are attached the brushes a and a, to the hub a, is attached the brush a, and toxthe hub a is attached the brush a. Above the brushes are contacts 100 88 87 97, and below said hub are

contacts

99, 90, 89, and 98, brush on making contact with the contact 100 or 99, dependent upon the direction in which it is moved, the brush a with

contacts

88 or 90, the brush a with contacts 87 or 89, and the brush a with contacts 97 or 98. The hub a is directly connected with one pole of the source of current supply by wire 80. The contacts 100 and 99 are directly connected with each other by wire, and con- Serial lie-564,735. (No model.)

tacts 88 and 89 are cross-connected, and so are

contacts

87 and 90, and 97 and 98 are also connected together. The direction in which the switch is moved merely determines the direction in which the current passesto the motor, or rather to the armature. Otherwise no diiference is caused by the change of dircction of the throw of the switch.

The connection to the field of the motor is madein the following manner, supposing the switch to be moved so that the brushes come in contact with the

contacts

99, 90, 89, and 98: From cont-act 99 a wire passes to the solenoid 101, having a contact 104 connected with its core, from the solenoidlOl to one side of the field, from the other side of the field to the contact 98, from thence to the hrusha, and from the brush a to the fieldresistance 96, thence through the arm 79 to a contact 300, which contact is connected with the controllingesolenoid 83, thence to the other pole of the source of current supply. The current to the armature passes from thr.v contact 90 directly to one pole of the armature, from thence back to the contact. 89, thence to the brush (F, from brush a through wire 85, to the solenoid'74, (the purpose of which will hereinafter be described,) and from the solenoid 7 4, by wire 84, to the armature-resistance 8T0, thence, by means of the arm '79, to the contact 300, thence through the solenoid 83 back to the opposite pole of the source of current supply. The movement of-the resistance-arm 79 is controlled by the solenoid 730, which is connecteddirectly with the contact 100, and from the other end of the solenoid a wire passes through the contact 300, through the solenoid 83,120 the other pole of source of current supply. The purpose of the controlling-solenoid 83 and its operation are fully described and claimed in certain Letters Patent issued to me, said patent being dated December 11, 1894, and numbered 530,773.

From the foregoing it may be seen that th solenoid 74 is directly in series with the armature of the motor. The coreof this solenoid is a second solenoid 73, to the core of which latter solenoid is attached the rod 7 0, having upon it the weight 71. This rod 70 is a forked rbd and surrounds the brake-lever Q of a friction brake-wheel Q upon the motor-shaft c. Between the weight 71 and the lever Q is placed a coil-spring 7 2.

q is a brake-band operated by the brakelever Q. The solenoid 73 on one side is in direct electrical connection with the contact 300 and the other side in direct electrical connection with the contact 100. As a consequence, when the switch 200 is operated, a circuit is completed to this solenoid 73 independent of the armature-circuit, that is, it is in shunt with the motor. This solenoid 73 carries at the end opposite to which the weight is attached an armature 75, which coacts with the magnet 76. This magnet 76 is connected to one pole of the source of current supply through a wire connected with contact 300, and is connected to the other pole of the source of current supply by means of a wire which is connected with the contact 94 on the switch 78. As shown at 77 in the drawing, this switch is controlled by the operating-bar P, and when the operating-bar is at its center the current is out off from this magnet 76, but when it is moved either to the right or left connection is made between contact 94 and either contact 93 or 92 and thus the circuit completed to this magnet. When the switch is operated, a circuit is made to the solenoid 73, which becomes energized, and its core moves so as to lift the weight 71. The strength of this solenoid 73 is just en ough-to release the weight 71 from the brake-lever Q. As the current passes to the armature, and dependent upon the amount of currentwhich the armature takes, the solenoid 74 becomes energized and proportionately lifts the brake.

Now let us take the application of the brake under varying conditions. If the elevator is ascending with a heavy load, itwill come t rest itself veryquickly as soon as the current is cut oif the machine. Such being the case it needs no assistance from the brake. On the other hand, if the elevator is ascending with the elevator properly loaded, and the operator slows down, the brake is not applied, because the armature is consuming a sufiicient amount of current to energize the magnet- 74 sufliciently to hold the brakefree from the wheel. In consequence the brake is not applied until the main circuit is entirely broken, and this can be as late as the operator may desire. On the other hand, if the operator is ascending with a light load, the amount of current passing through the solenoid 741s little or nothing. As a result it will be energized just enough to hold the brake off the wheel, and, when the operator turns the bar to slow down, as the current is cut off from the armature-circuit or resistance is thrown into it the strength of the solenoid 74 will be decreased and the brake applied proportionately to the decrease of its strength. It the load is over-counterbalanced, it will require considerable brake to stop it. Under these conditions, when the current is cut oil from the motor it is turned into a dynamo and generates a current. of its own, which passes through the solenoid 74 in the direction opposite to that in which the current passes through said solenoid from the source of current supply, and in consequence changes its polarity; but until the current is completely out off from the mot-orit will pass through the solenoid 73 in a direction opposite to that in which it passes through the solenoid 74 under these conditions, and as a consequence the action of the solenoid 74 will be to repulse the solenoid 7 3, and as a consequence apply the brake with-considerable strength.

The purpose of the magnet 76 is that under certain conditions where means are provided to regulate the speed of the motor independent of the brake, such, for instance, as electrical means, it is desirable to prevent the application of the brake until the current is completely cut off from the motor, that is, until the operating-bar is broughtto a central position. In this case the magnet 7 6 comes into play. This magnet is of such strength that it is not of itself sufficient to lift the solenoid 73, but when the solenoid 73 has been lifted by the solenoid 74, so that contact is made between the armature 75 and the armature 76, it will hold it in such position until the current is cut off. This current to the magnet 76 is controlled by means of the switch 78 upon the operating-bar P, as before described, so that the brake is held off until the bar P is brought to a central position. When it is brou ght to this central position, the connection between the armature 75 and the magnet 76 of course is broken, and as a consequence the solenoid 73 is capable of moving so as to applythe brake, and it is so moved proportionately as the current in the armature-circuit is decreased, thus decreasing the strength of the solenoid 74, or due to the extent to which the

solenoids

74 and 73 are energized in opposite directions.

The purpose of the solenoid 101 and its op erationis as follows: 103 and 1.02 are two contacts which are in electrical connection with wires 84 and 85, leading to and from solenoid 74. When the solenoid is deenergized, the contact 104 connects these'contacts 103 and 102 and short-circuits the current from the solenoid 74, and when the solenoid 101 is ener zed this connection is broken and the solenoid 74 sin the armature-circuit. Therefore it for any cause the field should become deranged and the'solenoid 101 deenergized current is cut off from solenoid 74 and the brake applied to a certain extent.

Having now fully described my invention, what I claim and desire to protect by Letters Patent, is-- 1. The combination with an electric motor, a source of current supply and motor-controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever; a solenoid in series with. the motor-armature circuit, said solenoid having a wound core, said core being in shunt with the main, the brake-lever being controlled by the said solenoid.

2. The combination with an electric motor, a source of current supply and motor-controlling mechanism, of a brake-wheel and brake for said motor, .a brake-lever, a solenoid in series with the motor-armature circuit, said solenoid having a core, the brake-lever being controlled by the said solenoid, a switch device in the circuit to the solenoid, an electromagnet controlling said switch device, said magnet being in the circuit to the field of the motor.

3. The combination with an electric motor, a source of current supply and motor controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever, a solenoid in series with the motor-armature, said solenoid having a wound core, said core being in shunt with the main, the brake-lever being controlled by the said solenoid, a switch device in the circuit tothe solenoid, an electromagnet controlling said switch device, said magnet being in the circuit to the field of the motor.

4. In combination with an electric motor, a source of current supply and motor-controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever, an electromagnet in shunt with the main, and connection between the armature of said magnet and the brake-lever. I

5. The combination with an electric motor, asource of current supply and motor-controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever, an electromagnet in shunt with the main, and connection between the armature of said magnet and'the brakelever, and a switch in said last-mentioned circuit controlled by the motor-controlling mechanism.

6. The combination with an electric motor, a source of current supply and motor-controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever, an electromagnet in shunt with the main, and connection between the armature of said magnet'and the brake-lever, a switch in said last-mentioned 5o circuit controlled by the motor-controlling mechanism, the arrangement being such that in the movement of the motor-controlling mechanism to the center said last-mentioned circuit is broken prior to the breaking of the circuit to the armature.

7. The combination with an electric motor, a source of current supply and motor-control ling mechanism, of a brake-wheel and brake for said motor, a brake-lever, a solenoid in series with the motor-armature circuit, said solenoid having a wound core connected to the brake-lever, said core being in shunt with 'the' main, an electromagnet, in shunt-with the main, the solenoid-core being connected -to the armature of said magnet.

8. The combination with an electric motor, a source of current supply-and motor-controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever, a solenoid in series with the motor-armature circuit, said solenoid havin'ga wound core connected to the brake-lever, said core being in shunt with the main,- an electromagnet in shunt with the main, the solenoid core being connected to the armature of said magnet, a switch in said last-mentioned circuit controlled by the motor-controlling mechanism.

9. The combination with, an electric motor, a source of, current supplyand motor-controlling mechanism, of a brake-wheel and brake for said motor, a brake-lever, .a solenoid in series with the motor-armature circuit, said solenoid having a wound core connected to the brake-lever, said core being in shunt with the main, an electromagnet in shunt with the main, the solenoid-core being connected to the armature of said magnet, a switch in said last-me tioned circuit controlled by the 'motor-controlling mechanism, the arrangement being such that in the movement of the motor-controlling mechanism to the center said last-mentioned circuit is broken prior to the breaking of the circuit to the armature.

In testimony of which invention I have hereunto set my hand.

FRANK E. IIERDMAN. Witnesses:

a C. D. HOY'l,

J. J. OMEAR.