US650666A - Apparatus for controlling electric motors. - Google Patents

Description

No. 650.666. Patented May 29, I900.

' A. W. BERRESFORD & H. J. WIEGAND.

APPARATUS FOR CONTROLLING ELECTRIC-MOTORS.

(Application filed Mar. 22, 1900.) (N o M o d e i "may 7 UNITED STATES PATENT OFFICE.

ARTHUR N. BERRESFORD AND HENRY J. WIEGAND, OF \VESTFIELD, NEW JERSEY.

APPARATUS FOR CONTROLLING ELECTRiC MOTORS.

SPECIFICATION forming part of Letters PatentNo. 650,666, dated May 29, 1900. Application illed March 22,1900. Serial No. 9,687. No model.)

Our invention relates to certain new and useful improvements in apparatus for controlling electric motors, and has for its object, more particularly, to provide new and improved means for automatically opening or breaking the circuit when the current exceeds a predetermined amount, combined with any well-known or approved means for breaking the circuit when the current falls below a predetermined amount.

Our invention has more particularly for its object to provide, in combination with a rheostat, a rheostat contact-lever and a mainline switch-lever hinged on a common axis, of means under the control of the rheostatlever for permitting the closing of the switchlever when the rheostat-lever is in its normal position at the limit of its inward movement and for preventing the closing of the switchl'ever when the rheostat-lever is in positions away from its normal position.

A practical embodiment of our invention is represented in the accompanying drawings, in which- Figure 1 is a diagrammatic view of our improved apparatus, showing the circuit connections controlled thereby, the rheostat contact-lever being shown in full lines at the limit of its movement away from its normal position and in dotted lines in its normal position, and the switch-lever being shown in full lines at the limit of its closed position and in dotted lines at the limit of its normal open position. Fig. 2 is an enlarged front view of the apparatus, the rheostat contactlever being shown in full lines in its normal position out of contact with the resistancecoils and in dotted lines at the limits of its movement away from its normal position, and the switch-lever being shown in full lines in its open position and in dotted lines in its closed position. Fig. 3 is a side view of the device, the resistance-coils and the box in which they are contained not being shown. Fig. 4 is a detail view showing the manner of releasing the switch-lever when in its closed position. Fig. 5 is a detail top plan View of the hinged end of the switch-lever and its adjacent parts, the rheostat contact lever and the spring, tending to swing the two 1evers to the limits of their swinging movements toward each other, being removed from the hinge-pintle. Fig; 6 is a top plan View of the stationary disk which carries the pawl, which is held normally in engagement with the annular rack-bar upon the inner face of the switch-lever. Fig. 7 is an inverted plan view of the hinge end of the switch-lever. Fig. 8 is a section taken in the plane of the line 8 8 of Fig. 5. Fig. 9 is a similar section showing in connection therewith the manner of releasing the pawl from engagement with the switch-lever by means of the rheost-at contact-lever; and Fig. 10 is a detail view, in side elevation, of the parts shown in Fig. 5 looking toward the side of the disk in which is mounted the spring-actuated pawl.

Our improved apparatus is mounted upon a base-plate A of any suitable insulating material-such, for instance, as slate-which base-plate in the present instance forms the cover of a rheostat-box. (Not shown.) A hinge pintle or stud Bis firmly secured to the base-plate A and uprises a short distance therefrom. A stationary disk or block O is suitably secured to the base-plate A around the hinge-pintle B. This stationary disk 0 is provided with an upwardly extended centrally-arranged circular stud 0, upon which is hinged the inner end of the switch-lever D. The rheostat contact-lever E is hinged on its inner end upon the pintle or stud B, the free end of the contact-lever being provided with the usual contact-plate e, which is caused to successively engage a number of contactpoints a of the resistance-coils of the rheostat. (Not shown.) A stop a is rigidly secured to the base-plateA insuch a position that when the contact-lever E is in engagement therewith the said lever will not be in engagement with any of the contact-points which lead to the resistance-coils of the rheostat. A spring F is engaged with the two levers D and E, tending. to hold them against the stop a. g In the present instance this spring F is shown as provided with a coiled portion f, embracing the hinge pintle or stub B and having one of its ends f engaged with a pin e uprising from the contact-lever E and its other end f in engagement with the switch-lever D. The stop a is preferably provided with a suitable cushion a? for deadening the jar and noise caused by the lever striking the stop under the tension of the spring E, which cushion may be a tubular section of rubber, for example. The rheostat contact-lever E is further provided with an insulated handle 6 arranged to be grasped by the operator. This lever is further provided with an armature 6 arranged in position to be engaged with an electromagnet G when the lever E is swung outwardly to the limit of its movement away from its normal position. The electromagnet G serves to hold the lever in such position so long as a normal current is passed therethrough, but which will release the lever, permitting it to be returned to its normal position by the spring F when less than a predetermined current is passed through the magnet. A contact-pointe of the main line is secured to the base-plate A a short distance from the stop a, the said contact-point being so arranged that the usual contactplate d of the switch-lever D will be caused to engage therewith when the lever is swung outwardly to the limit of its movement in that direction.

I The switch-lever D is provided with an insulated handle 01 for the use of the operator. The means which we have shown for locking the switch-lever D at the limit of its outward movement in its closed position comprises a spring-actuated latch H, hinged on a pin h, secured to the base-plate A, which latch is provided with a hook 71, arranged to engage a pin d uprising from the switch-lever D. The spring for holding the latch 11 yieldingly at the limit of its inward movement is denoted by 71.2 and is shown in the present instance as being coiled around the pin 71, having one end engaged with the said latch and its other end with the base-plate A.

An electromagnet I is secured to the baseplate A, which electromagnetis provided with a movable core 1', which is arranged to raise a movable pin 2' when an overload is established in the electromagnet I. This pin t engages the latch H and as it is raised swings the hook 71. away from its engagement with the pin d 011 the switch-lever D. The movable core 2' may be adjusted upwardly or downwardly, so as to permit it to be operated by overloads of varying degrees to suit different requirements.

The connection which we employ between the rheostat-lever and the switch-lever for permitting the rheostat-lever to be swung independently of the switch-lever and to perinit the switch-lever to be swung inwardly independently of the rheostat-lever, but will cause it to be locked against outward movement when the rheostat-lever is in any other than its normal position at the limit of its inward movement, is as follows: The disk 0 is provided with a vertical opening 0 therethrough near its periphery, which vertical opening commu nicates with a transverse opening 0 leading to the periphery of the disk. A spring-actuated pawl J may be inserted through the transverse opening 0 into position within the vertical opening o,and a spring j is arranged in position to press the free end of the pawl normally upwardly above the top of the said disk into engagement with an annular rack-bar (i preferably formed in the bottom of the hinge end of the switch lever D. The pawl-and-ratchet connection between the switch-lever D and the disk 0 is such that the switch-lever may be freely swung from its closed to its open position at all times, but will be prevented from being swung in the opposite direction except when the pawl is positively released from its engagement with the teeth of the rack-bar. The pawl J is provided exterior to the disk 0 with a shoej,

having a downwardly-curved upper edge arranged to be engaged by a downwardly-extended stud 6 carried by the rheostat-lever E, so that when the stud is engaged with the shoe the pawl will be depressed out of its ongagement with the ratchet on the switch-lever D.

The operation of our invention is as follows: When it is desired to start a motor, the switchlever D must be first positively swung from its open to its closed position, where it will be held by the latch H. The rheostat-lever E may then be swung outwardly away from its normal position out of contact with the resistancecoils. If this rheostat-lever should be swung to the limit of its outward movement, it will be held in that position by the electromagnet G. If an overload should be induced in the electromagnet I, it will draw the movable core 2' upwardly, thus causing the pin '6 to trip the latch H and permit the switchlever D to be returned by the spring F to its normal open position. If, on the other hand, an underload is established,the electromagnet G will release the armature e carried by the contact-lever E, and permit it to be returned to its normal position out of contact by the spring F. If the operator should attempt to swing the switch-lever into its closed position while holding the rheostat-lever at any position other than its normal position out of contact, it will be impossible for him to do so because of the pawl-and-ratchet connection with the stationary disk 0 011 the base A. It will thus be seen that the switch-lever D can only be closed when the contact-lever E is in its normal or open position out of contact.

It will be seen that we are enabled to provide a very simple arrangement for mounting the pawl J by reason of the vertical opening 0 and the transverse opening 0 leading therefrom in the stationary disk 0, thus permitting the pawl and its shoe to be formed of IIO a single piece and permitting the pawl to be inserted through the transverse opening 0 into its position within the vertical opening 0.

WVhat we claim is 1. In combination with a rheostat, of a suitable base, a switch-lever and a contact-lever hinged on a common axis on the base and means for locking the switch-lever to the base against a movement away from the contactlever when the contact-lever is in certain positions, substantially as set forth.

2. In combination with a rheostat, of a suitable base, a switch-lever and a contact-lever hinged on a common axis on the base, a paw1- and-ratchet connection between the switchlever and base and means carried by the contact-lever for controlling the pawl-and-ratchet connection between the switch-lever and the base, substantially as set forth.

3. In combination with a rheostat, of a suitable base, a switch-lever and a contact-lever hinged on a common axis on the base, a pawl carried by the base, a ratchet carried by the switch-lever and means carried by the contact-lever for controlling the movement of the pawl for connecting and disconnecting the switch-lever with the base, substantially as set forth.

4. In combination with a rheostat, of a suitable base, a contact-lever and a switch-lever hinged on a common axis on the base, a stop on the base between the two levers and means for normally holding both of the levers at the limits of their inward movements in engagement with the stop, substantially as set forth.

5. In combination with a rheostat, of a suitable base, a contact-lever and a switch-lever hinged on a common axis on the base, a stop fixed t0 the base between the two levers, means for removably holding the switch-lever in its closed position, separate means for removably holding the contact-lever at the limit of its outward movement and means for returning the two levers to the limits of their inward movements into engagement with the stop when they are released from their hold.- ing means, substantially as set forth.

6. In combination with a rheostat, of a suit able base, a contact-lever and a switch-lever hinged on a common axis thereon and means for locking the switch-lever against a m0vement away from the contact-lever when the contact-lever is in certain positions, substantially as set forth,

7. The combination with a stationary disk or block having a vertical opening and a transverse opening leading therefrom to the periphery of the disk or block, of a pawl fitted to be inserted through the said transverse opening into position within the vertical opening in the block, substantially as set forth.

8. In a circuit-controlling device, a suitable base, two levers hinged upon a common axis thereon, and means for locking one of said levers against an outward movement away from the other lever when the latter is in certain positions, substantially as set forth.

In testimony'that we claim the foregoing as our invention we have signed our names, in presence of twowitnesses, this 20th day of March, 1900. I

ARTHUR WV. BERRESFORD; HENRY J. WIEGAND. Witnesses:

R. H. MANsFIELD, Jr., PERoIvAL II. KETCHAM.

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