US947993A - Projector-lamp. - Google Patents

Description

J. W. KELLOGG.

PROJECTOR LAMP.

.APPLIOATION FILED JULY 24. 1908.

Patented Feb. 1, 1910.

Inventor Witnesses:

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UNITED STATES, PATENT OFFICE.

JAMES W. KELLOGG, OF SCI-IENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROJECTOR-LAMP.

To all whom it may concern:

Be it known that 1, JAMES W. KELLooe, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Projector- Lamps, of which the following is a specification.

This invention relates to electric arc lamps for projectors, in which the electrodes are arranged preferably in a horizontal position, with a feed screw for each electrode. The two screws are geared together in the proper ratio to keep the arc at the focus of the projector, and are revolved by an actuator, such as a pawl, engaging with a driving wheel, such as a ratchet wheel, on one of them, the pawl being actuated by an electromagnet in shunt to the arc.

My invention has for its object the automatic separation of the carbons when starting the arc, or when, in operation, the arc voltage drops below normal. I accomplish this by providing another electromagnet and actuator operating to turn the feed screw in the opposite direction to that in which the feeding-together magnet revolves it. This reverse or feeding-apart magnet is held normally out of circuit by an electromagnet in shunt to the arc; said magnet permitting a closure of the circuit of the feeding-apart magnet only in case the arc voltage is below normal.

The accompanying drawing is a diagrammatic illustration of a projector embodying my invention, the lamp and feed screws being shown as if swung around into the plane of the ratchet wheel.

The electrodes 1 2 are carried in holders 3 4, which are fed together and apart by feed screws 5 6 connected by the gears 7 8. On one of said screws is a driving wheel, such as the ratchet wheel 9 which can be driven in a direction to feed the electrodes toward each other, by means of a spring-actuated pawl 10 carried by the armature lever 11 of the feeding-together electromagnet 12. In the drawing the wheel and pawl are shown broken ofi' from the feed screw and turned to a position at right angles to that in which they really stand, in order to show them in elevation instead of edge view. A spring 13 urges the armature lever 11 away from the magnet 12, and closes the circuit thereof at the contacts 14; said magnet being in shunt Specification of Letters Patent.

Application filed July 24, 1908.

Patented Feb. 1, 1910. Serial No. 445,080.

! to the arc. The tension of the spring 13 is adjusted to overcome the pull of the magnet when the drop across the arc is normal, so that the pawl remains in the position shown, with its tail 15 against the stop 16 and its nose out of engagement with the ratchet wheel. But when the arc lengthens to a point where its resistance compels an abnormal fiow of current through the magnet winding, the tension of the spring is overcome and the armature moves downward; the pawl sliding over the teeth of the ratchet wheel. This action, however, breaks the circuit of the magnet at 1A, which deencrgizes the magnet and permits the spring to pull 1 up the armature, and at the same time causes the pawl, which has hooked into a tooth of the ratchet, to turn the wheel clockwise and feed the carbons together. This vibration of the armature continues so long as the drop across the arc is greater than normal, and the result is that the electrodes are fed toward each other to compensate for their consumption, until the resistance of the are once more becomes normal. In case, however, the voltage drop across the electrodes becomes less than a predetermined amount, owing to their getting too close, or even touching, as will be the case when the lamp is to be started, there is a necessity for some device to separate them. Such a device is the subject of this present invention. It consists of an electromagnet 17 connected across the line, with its armature 18 mounted on a lever 19, which is connected with the lever 20 on which is pivoted a spring-actuated pawl 21 having a tail 22. A stop 23 cooperates with said tail and acts to disengage the pawl from the ratchet wheel when said armature lever is down. A spring 24 is arranged to lift said lever and cause the pawl 21 to actuate the wheel in a reverse direction from that produced by the pawl 10.

In order to keep the reversing pawl 21 out of engagement with the wheel during the operation of the feedingtogether magnet an electromagnet 25 is arranged to act upon the lever 19, said magnet 25 being in shuntto the arc and in parallel with the magnet 12. The tension of the spring 2% is less than that of the spring 13, so that the lever 19 will be pulled down by the magnet 25 while the resistance of the ark remains at or above normal. The magnet 25, therefore, keeps the pawl 21 inactive during the normal operation of the lamp; But when the arc voltage drops so low that the magnet 25 is overcome by the spring 24, the parts assume the position shown in the drawing, the pawl 21 rising, pushing vthe ratchet wheel over in a counterclockwise direction and feeding apart the electrodes. This movement of the armature lever, however, closes the circuit of the magnet 17 at 26 and the energizing of this magnet by the full line voltage causes it to pull down the lever 19 and engage the pawl with another tooth of the ratchet. As the downward movement of the lever breaks the circuit of the feeding-apart magnet 17, the spring 24 again lifts the lever, giving the feed screws another backward impulse, whereby the electrodes are fed apart still farther. This action continues until the electrodes have been separated far enough to throw suiiicient current through the magnet 25 to enable it to retain the lever 19 in its downward position once more. By the automatic operation of these magnets and actuators acting upon the driving wheel and turning the feed screws forward or backward, as the case may be, the lamp is started and kept burning in an efficient and satisfactory manner.

that I claim as new and desire to secure by Letters Patent of the United States, is

1. A projector having geared feed screws,

- a driving wheel on one of said screws, a

feeding-together actuator and a feedingapart actuator adapted to engage with said wheel, an electromagnet in a normally closed circuit controlled by said electromagnet for operating the feeding together actuator, an electromagnet in a normally open circuit for operating the feeding-apart actuator, and an electromagnet in shunt to the are for keeping the circuit of the feedingapart actuator open while the arc voltage is at or above normal.

2. A projector having geared feed screws, a. driving wheel on one of said screws, 2. feeding-together actuator and a feedingapart actuator adapted to engage with said wheel, an electromagnet in shunt to the arc, an armature lever for said magnet connected to the feeding-together actuator and controlling the circuit of said magnet, an electromagnet connected across the line and having an armature lever connected to the feeding-apart actuator and also controlling the circuit of said electromagnet, and a third electromagnet in shunt to the arc and acting upon the same armature lever as the feedingapart magnet.

3. A projector having geared feed screws, a driving wheel on one of said screws, a feeding-together actuator and a feedingapart actuator adapted to engage with said wheel, an electromagnet in shunt to the arc, an armature lever for said magnet connected to the feeding-together actuator and controlling the circuit oi said magnet, an elec tromagnet connected across the line and having an armature lever connected to the feeding-apart actuator and also controlling the circuit of said electromagnet, a third electromagnet in shunt to the arc and acting upon the same armature lever as the feedingapart magnet, and springs attached to said armature levers and acting in opposition to their respective magnets, the spring for the feeding-together magnet being the stronger.

In witness whereof, I have hereunto set my hand this 22nd day of July, 1908.

JAMES l/V. KELLOGG. lVitnesses BENJAMIN B. HULL, HELEN ORFORD.

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