US1838959A - Electric door-motor - Google Patents

Description

Dec 29, 193E. v R. J. PARSSONS 1,338,959

ELECTRIC DOOR MOTOR Filed Aug. 1'7, 1926 avwemvoc ROBERT J. PARSONS Patented Dec. 29, 1931 UNITED STATES MENTS, TO CONSOLIDATED CAR-HEATIN A COBIORATIONOF NEW YORK PATENT OFFICE I ROBERT .1. lmmsons, or scimnnc'rany, NEW YORK, ASSIGNOR, IBY MEsNE Assum- G COMPANY, INC., OF ALBANY, YORK,

Erncra rc noon-Moron Application filed August 17, 1926. Serial at. 129,829.

For a detailed description of the present form of my invention, reference may be had to the following specification and to the ac companying drawings forming a part thereof, wherein Fig. 1 is a plan partly in section of my device;

Fig. 2 is a front view of the switch box with the cover removed and Fig. 3 is a diagram of the circuits.

My invention relates to electric door operators wherein an electric motor is arranged to reciprocate acar-door, or any door requiring similar movement.

Referring to Fig. 1 E represents an electric motor having its casing connected to a gear-box J and a switch-box F. p The armature shaft of the motor carries a spur-pinion which drives a gear-wheel 21 on the shaft of which is a second pinion 22 that drives a gear-wheel 23, and on the shaft of said gearwheel 23 is a third pinionv 24 that drives gearwheel 25 on the door-arm shaft D. The doorarm is shown at G and, ina manner now well known and requiring no illustration, oper ates the door back and forth by a movement over an arc of approximately 180 degrees, a roller on the outer end of the arm engaging a vertical guideway on the rear edge'of the door. The door-arm shaft D enters the switch-box F and, as appears in Fig. 2, carries two cams H and K which, for convenience of illustration, are shown separately in the figure, one above the other, although it is to be understood that in practice the two cams are placed side by side on the common shaft D, each acting on its individual set of switches. The cam H acts alternately on the levers P and Q while cam K acts alternately on the levers S and R. The lever Q, operates the spring-pressed switch that opens and closes the connection between contacts 11 and 12, while lever P operates the similar switch Y which opens and closes-the connection between'contacts 13 and 14 The cam H is shown in its midway position both switches being open. In a similar way the cam K controls the closure; of the connections between contacts 9 and 10 of switch V on the one hand and contacts 15 and 16 of switch W on the other hand. 1

The cam H is longer in a circumferential direction than cam K, and, therefore, as it moves to one side or the other, will operate switch X or Y before cam K operates switch V or W. i

In operation we may assume that the motor is propelling the door towards its closed position and shaft D with cams H and K is rotating in an anti-clockwise direction, havin reference to Fig. 2. As the door approac es the closed position the first effect will be the closing of switch X by the action of cam H on lever Q. The result of this may be seen by'reference to the circuit diagram of Fig. 3. This assumed door-closing direction of the motor movement has been estab lishedby moving the manual control-switch A to the left, thereby connecting contacts 1 and 5, also contacts 2 and 6 of that switch, while the contacts 9 and 10 of switch V (which is the door-closing limit switch) are as yet unopened. Thereby the current will pass from trolley T, to contacts 6 and 2, to contacts 10 and 9, to field-magnet A of the motor, to motor armature C and to ground. The field-magnet coil A is so wound as to give the motor its desired door-closing direcdoor-opening current of that coilnamely, in a direction to cause a co-operation of fieldmagnet coils A- and B to close the door), thence to contacts 5 and 1 of the controlswitch, to contacts 12 and 11, now closed, of switch X, and to ground. By the aforesaid closure of switch X three effects are. roduced: (1) the coo erative connection a oresaid of field-coils and B, (2) the voltage applied to armature C is reduced (3) the voltage applied to field-coil A is increased. As a result the motor speed is reduced, but the motor torque is maintained, or even in creased. The reduction in motor speed is due to the stronger field magnet and the re duced voltage applied to its armaturenot to a weakening of its torque. Thereby the motor is enabled to complete the run of the door wbecause of its maintained torque, although its-speed is reduced preparatory to its stopping. Consequently the motor slows down as it approaches the end of its run, and the inertia of its high-speed armature, which has such alarge gearing ratio with respect to the comparatively slow-moving door, is brought under control initially prior tothe actuation of the limit-switch. Following the operation of switch X, as just described, by the cam H, comes the operation of limitswitch Vby cam'K and lever S. That interrupts the flow of current from'trolley T totheimotor coils, but there-still remains a closedcircuit for the motor armature O,from ground on one side of it,'through the armature itselfpand thence through field-coil B, control-switch contacts 5 and 1, contacts 12 and "11 of switch X and back to ground. This puts a final brake-effect on the motor which nowacts as a short-circuited generator and brings it'to rest. The action is the same for the opposite direction of movement of the doorand motor, theswitches Y and V being then operatedin succession with'thesame effect as the aforesaid switches X and V. In each case the motor is first automatically weakened .and itslimit-switch then opened ina'way-to give abraking'effect to bring it mechanically to a stop.

.It willbe noted that while field-magnet coil 3B,.when acting alone, willhave an effect which is the'reverse of the corresponding coil A when acting alone, yet when switch X is closed,"as'above described, both coils will be energized to give the same direction of rotation and will therefore supplement each other. The two coils when thus supplementingeach other will double the effect of A or B when acting alone. In addition, the drop in-voltage thereby-applied to the armature will increase somewhat'the VOlAlfIQ applied to coil A because the-line voltage remains unchanged. Therefore the field-magnet effect is more. than doubled when'the two fieldn1agnet coils thus supplement each other. After the aforesaid closure of switch X, which inaugurates the first slowing-down stage or period, the limit switch V is opened and there byithe current supply is cut off. This inaugurates the second slowing-down stage or period. The motor then beginsto actas a generator andthe stopping effect of that action isamaintaine'd until the door and motor stop. WVhileI do not now know of any motor other than a door motor with its door ,qea red thereto that would call for my braking or stopping device, yet it will be understood. that the door shaft mentioned in the following claims includes any equivalent shaft requiring the same operative treatment as the shaft D of my above described apparatus.

lVhat I claim as new and desire to secure by Letters Patent is:

1. The combination with a door shaft, of a. driving motor connected thereto and stopping therewith, said motor including an. armature and oppositely wound tiel d magnets so that the motor may be operated in either direction, a supply circuit for said motor, a normally closed limit switchcontrolling said circuit and one of said field magnets, means for opening said switch at a predetermii'ied time during the operation of said door shaft, a normally open'field magnet switch, means for operating the field magnet switch in advance ofthe operation of-said limit switch, and means associated withsaid field magnet switch for connecting said field magnets in series with each other so to reduce the voltage supply to said armature.

The combination with a door shaft, of a driving motor conccted thereto and stopping therewith, said motor including an armature and two field magnet coils connected respectively for opposite directions of armature rotation, a supply circuit for said motor, and an automatic controller for said motor comprising twoscts of switches, each set including a limit switch for controlling the motor circuit and one of said field magnet coils, means for operating said switch to open the motor supply circuit at a predetermined time during the operation of'said door shaft, :1 field magnet switch acting in advance of said limit switch, and means associated with said limit switch to connect the inactive field magnet coil tothe supply and to reduce the voltage supplied to said armature.

3. The combination with door shaft, of a driving motor connected thereto andstopping therewith, said motor including an armatureand oppositely wound field 1nagnets so'that the motormay be operated in either direction, a. supply circuit for said motor, a manual reversing switch for said motor, and an automatic controller in series with said manual switch,'said controller in cluding a normally closed limit switch controlling said circuit and one of said field marrnets, means for opening said switch at a predetermined time'during'the operation of the door shaft, a normally open field magnet switch, means for operating the field magnet switch in advance of the operation of said limit switch, and meansassociatcd with said field magnet switch for conecting the inactive field magnet coil to the motor supply circuit and to reduce the voltage supplied to said armature.

4t. The combination with a door shaft, of a driving motor connected thereto and stopping therewith, said motor including an armature and. two field magnet coils arranged for opposite directions of armature rotation, a supply circuit for said motor, a manual reversing switch, and an automatic controller including a limit switch controlling said motor circuit and one of said field magnets, a field magnet switch, means associated with said field magnet switch for connecting the inactive field magnet coil to said motor supply circuit so as to reduce the voltage supply on said armature, and cams mounted on said shaft and positioned to engage and operate the respective switches, the cam for operating said field magnet switch being positioned to actuate the same in advance of the operation of said limit switch.

The combination with a door shaft, of a driving motor connected thereto and stopping therewith, said motor including an armature and oppositely wound field magnets so that the motor may be operated in either direction, a supply circuit for said motor, a manual switch having two sets of contacts, means associated with one set of contacts for selectively connecting said circuit to the ground or through one of said field magnets and the armature, said means including a normally closed limit switch, and means for automatically opening said switch at a predetermined time during the operation of said shaft, means associated with the other set of contacts for connecting the last mentioned field magnet to ground'through the other field magnet, said means including a normally open switch, and means for automatically closing the last mentioned switch in advance of the opening of said limit switch so as to reduce the voltage supplied to said armature.

6. The combination with an electric motor having two field magnets arranged for opposite directions of motor rotation, and an armature having a terminal connection with both coils at a position intermediate between them, a limit switch normally biased to circuit closed position and controlling the circuit through one of said coils, a ground connection around said armature and including the other coil, avoltage switch controlling the ground connection, said voltage switch being normally biased to open circuit position, a control switch provided with contacts for establishing circuit to the motor through the limit switch and through the voltage switch respectively, a shaft rotatably actuated by said motor and having cams, and means interposed between said cams and said switches for efl'ecting operation of the switches during rotation of said shaft, said cams being positioned to operate the switches in a predetermined sequence.

Signed at Albany, county of Albany, State of New York, this 6th day of Aug, 1926.

ROBERT J PARSONS.

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