US2447074A - Controller for towing winches and other machines - Google Patents

Description

Patented Aug. 17, 1948 UNITED STATES PATENT OFFICE CONTROLLER FOR TOWING WINCHES AND OTHER BIACHINES Application August 28, 1946, Serial No. 693,496

Claims.

This invention relates to control for towing winches.

An object of the invention is to improve in respect of hawser reclaiming, the control disclosed in our Patent No. 2,372,963, granted April 11, 1945.

The control of the aforementioned patent is such that the hawser for automatic payout must overcome motor torque opposing payout plus the friction of the winch and associated gearing, and such that the automatic reclaiming cycle is dependent upon a substantial drop in hawser pull. In practice such drop in pull was found almost always to follow promptly automatic payout but occasional unusual conditions were found to result in an unduly protracted period where the drop was insufficient to initiate the reclaiming cycle, such initiation having been made dependent upon a slight motion of the motor in reclaiming direction. When such conditions occurred the stalled motor was maintained energized to hold against hawser pull, whereas when the automatic reclaiming means is effective the motor is disconnected from circuit and braked to hold against hawser pull, which is preferable, and an object of the present invention is to overcome this minor disadvantage of the control of the patent.

Another object is to accomplish the desired results without modification of the means disclosed in the aforementioned patent except for the mere addition of a simple and reliable relay to parallel the previously provided friction switch operatively associated with the motor.

Another object is toprovide improved reclaiming means which may be advantageously employed in winch control other than the specific form disclosed in the aforementioned patent.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawing shows diagrammatically one embodiment of the invention, it being understood that the embodiment illustrated is susceptible of various modifications without departing from the scope of the appended claims.

The control selected for illustration is except for the aforementioned added relay and its connections physically the same as that disclosed in the aforementioned patent, and the drawing hereof bears the same reference characters as the drawing of the patent. The patent not only shows the control but also shows the mechanism to be controlled and contains a full description of both, wherefore reference is hereby made to such patent to avoid need herein of further illustration or a more detailed description of the control covered by the appended claims.

Referring to the drawing hereof, the winch drive illustrated comprises a motor M having an armature A and a separately excited field winding F. The motor armature is supplied by a generator G having an armature A, a separately excited field winding F and a seres field winding F The field windings F and F are supplied from lines L and L The generator field winding F acts cumulatively with the field winding F under certain conditions, and differentially under other conditions. The motor has a brake (not illustrated) to be electromagnetically controlled by means including a Winding B.

The loop for the motor and generator armatures includes resistors R to R which are under the control of switches ID to 5D, and also includes series coils IFD and IFA' for control of relays IFD and IFA. Also the loop has connected across the same a winding VR for a voltage relay.

In the foregoing respects the disclosure hereof is the same as that of the aforementioned patent, whereas the drawing hereof shows connected across the motor armature an added winding IVR. for control of an additional relay IVR which has normally engaged contacts IVR The contacts and winding of relay IVR have been shown in a widely separated relation and hence their connection has been indicated by a broken line extending from said contacts to the plunger of said winding.

Except for the added voltage relay just mentioned the control means shown are the same as those found in the aforementioned patent, and will be understandable from the following description of operation which as to comm-on subject matter is mere repetition of the description found in the patent.

As set forth in the patent, when the hawser has been paid out to normal length the drum of the master switch MS is thrown to its automatic position, deenergizing transfer relays [TR and 2TB, with the result of deenergizing coils I13, 23 and BR to stop the motor and set its brake.

Also as set forth in the patent, if then a surge occurs exerting an abnormal pull on the hawser, the tension switch drum TS will move to its position I to energize switch E, which is followed by energization of switches IF, 2F and BR. Under these conditions the left hand terminal of coil E of switch E has a connection through contacts 2TB, of transfer switch 2TB, contacts 6, 6 l 1 to contact 2| of tension switch TS and 3 through contacts 2W, 220 and to line L. Coil E when energized engages contacts E to connect brake relay coil BE in circuit and contacts E complete a circuit from the supply of coil E to and through contacts ETR to IF and 21?. ll andEF then respond tocompleteethe' cir-.- cuit of the generatorfield winding F'for current flow in a direction to cause the motor to oppose payout of the line, the motor brake being at such; time released. Also at thistimeswitches.,2D-to 5D are energized to exclude resistors R to RF";

from the loop of the motor and generator armatures, resistor R remaining-in circuit. to absorb;

the regenerative energy. If the surge increases sufficiently the tension switch TS progressively disengages contacts 2"l-22 2323 E l-2G 25-25 to deenergize switches 2D to 5D for re-'- inclusion of the resistors controlled thereby, this permitting a higher payout speed with alimited increase in the retarding torque. As the surge decre ses tension switch TS ,Will:recloseprogres-' sively the switches 5D, 513,131), and r-2Dj,i-thereby keeping the retarding torque :and "subsequently the reclaiming torque atthedesiredzyalue.

Also as stated in the patent, when the, motor begins to reclaiinthapayed out hawser the friction switch-fiticloses tocomplete thecircuit of coil HR which then closes contacts HlFt-to short circuit the holdout coil i13 of the resistance switch lD. After lapse of a time element switch ED responds to exclude-all resistance, whereby the full generator-output is available for reclaiming.

As will'now be apparent, where the aforemen tioned unusual conditions are met "with and the drop in hawser pull is insufficient to permit the motor to rotate in reclaimingdirection, the friction switch 36 will not function as just described and the added relay iVR ofthe instant disclosure is provided to substitute temporarily for said friction switch 36.

The contacts of relay lVR parallel the contacts of friction switch and said relay contacts arenormally engaged, said relay-being designed and adjusted todisengage its contacts at all'voltages other than that corresponding to a very slow speed-of the motor. Accordinglythe relay con tacts are opened during payout. until the motor approaches stalled condition, whereupon the relay contacts engage to shunt the open friction switch Stand thereby initiate-thecycle of 'control above recited-as a function of closure of the friction switch. As the motor accelerates in'reclaiming direction after closure of friction switch relay EVE opens,-: leaving thereclaiming cycle dependent upon said frictionswitch.

I'hus need of any substantial drop in the hawser pull is unnecessary to initiate-the reclaiming cycle and the voltage relay through the medium of which the difficulty is overcome in nowise interfereswith the normal operation of the control inasmuch as it is energized to dis engage its contacts except: as the motor approaches stalled condition.

As aforeindicated, the further description of control apparatus and its operation to be found in the aforementioned patent is equally applicable to the herein disclosed control minus the voltage relays lVR and its connections.

What we claim as new anddesireto secure by Letters Patent is:

1. For towing winch control, the combination with a motor to be operatively connected to the winch, means to energizesaid motor for motor torque opposing'payout operation of the Winch and tending to effect reclaiming operation of the winch, and means to effect a reclaiming cycle of control for said motor following a payout cycle, the last mentioned means including for initiation of the reclaiming cycle, means operatively associated with said motor to beset in an ineffective position by rotation of said motor above a very slow speed and to be caused to move to an effec tive position as said motor approaches zero speed in a payout cycle.

2. For towing winch control, the combination with a motor to be operatively connected to the winch; means to energize said motor for motor torque opposing payout operation of the winch and tending to effect reclaiming operation of the winch, and means to effect a reclaiming cycle of control for said motor following a payout cycle, the last mentioned means including for initiation of the reclaiming cycle, a relay having a control winding connected across the motor armature and being adjusted to assume an ineffective position as said motor accelerates above ayery slow speed and to assume an effective positionas said motor approaches zero speed on payout operation of the winch.

3. For towing winch control, the combination witha motor to be operatively connected to the winch; means to energize said motor for torque opposing payout operation of the winch and tendingtoeilect reclaiming operation of the winch, and means to effect a reclaiming cycle of control for said motor following a payout cycle, the last mentioned means comprising for effecting such reclaiming cycle, means responsive to a slight motion. of the motor in reclaiming direction, and also :comprising supplemental means for initiating the reclaiming cycle, which supplemental means: is responsive to change in speed of "said motorand becomes effective as said motor approaches :zero speed on'payout operation of the winch:

4. For towing winch control, the combination with a motor to be operatively connected to the winch, means to energize said motor for torque opposing payout operation of the winch and tending to effect reclaiming operation of the winch, and means to effect a reclaiming cycle of control for said motor following a payout cycle, the last mentioned means comprising a friction switch operatively related to said motor and responsive to a slight motion of said motor in reclaiming direction thereby to effect a reclaiming cycle and also comprising means responsive to change in speed ofsaid motor for paralleling said friction switch" as said motor approaches zero speed on payout operation of the winch and for interrupting the parallel connection controlled there by when said motor operates in reclaiming direction.

5." For towing winch control, the combination with amotor to be operatively connected to the winch, means to energize said motor for torque opposing payout operation of the winch and tend ing to effect reclaiming operation of the winch, and means to effect a reclaiming cycle of control for said motor following a payout cycle, the last mentioned. means comprising a friction switch operatively related to said motor and responsive to .a, slight. motion of said motor in reclaiming directionthereby to effect a reclaiming cycle and also comprising a relay having contacts in parallel with said friction switch and a control winding connected across the armature of said motor.

EIVIND U. LASSEN. ALMON' A. JOHNSON;

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