US1239759A - Automatic electric-arc-control mechanism. - Google Patents

Description

H. M. BAKER, 1:. AUTOMATIC ELECHHC ARC CONTR OI. MECHANISM. APPLICATION mm ocr. 2|. 1914.

1,239,759. Patented Sept. ll, 1917.

UNITED STATES PATENT OFFICE.

HAYDN' m. BAKER, m, or BROOKLYN, NEW YORK, Assmaoa 'ro Auotrs'ros 'rnnanwsnn, an, or BROOKLYN, NEW some AUTOMATIC ELEOTRIC-ABC-CONTROL MECHANISM.

Specification of Letters Patent. Patented Sept, 11, 191 7.

Application tiled October 21, 1814. Serial No. 867,773.

To all whom it ma concern:

Be it known tint 1, Harms M. Barren, J12, a citizen of the United States, and resident of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Automatic Eleetrie-Arc- Control Mechanism, of which the following is a specification.

This invention relates to automatic. electrie'arc control mechanism designed to revide a device for feeding the carbons the are toward each other to compensate for-- the material bu'rned away in the production. of the are.

The object of my invention is to provide a mechanism which will be responsive to minute variations in the current occasioned by the varying distance between the carbons to automatically restore them to their positions of maximum brilliancy. My invention is desi ed particularly for use in connection wit i the are lamps employed in motion picture and stereoscopic itJPflltltllB and deal ed to perform the wor of the hand ad ustment commonly used in such 1am )8, and is arranged so as to permit either the land adjustment or the power adjustment of thecarbons.

My improved control device is designed to be extremely sensitive and t0 )er orm minute adjustments impossible to o tain by manual still thereby producing a far steadicrlight than is obtainable with the constructions now on the market.

In the accompanying drawings I have illustrated a preferred form of my invention. In the said drawings,

Figure 1 represents a side elevation of the entire device;

Fig. 2 shows the overnor device which will belater describe and Fig.3 is a detail view slio\ving ,.the connceting mechanism between the control 'dc- Vlt'O and the adjusting shaft.

Referring now to Fig. l, i. represents the supporting bracket of the canon holders of an are light such as employed in projection lamps, which bracket is supported in the usual manner on a standard 2. Swiveled to the bracket is a holder 3 alsoot usual construction which provides guiies for the rack bars 4 and 5 respectively, carrying the a per and lower carbons 4 and 5' of the light... The teeth of the rack-bars 4 and 5 engage the opposite sides of a pinion carried by the shaft 6 rotatably mounted in a sleeve 7 projecting from the rear face of the part 3.

The mechanism so far described is the construction commonly used in lights of this character. In such apparatus a knob is attached to the shaft by which it may be rotated by hand when desired to adjust the carbons toward or away from each other, according to the direction of rotation.

My automatic control mechanism operates through the shaft 6 to adjust the carbons and comprises a sleeve 8 fixedly attached to the shaft 6 and formed with a friction col-- lar at its inner end. Freol mounted on the sleeve 8 with its face in rictional engages ment with the collar is a worm gear 9, and enga 'ng the op osite face of the worm whee is a loose isk 10 capable of sliding movement on the shaft.

The sleeve 8 projects beyond the end of the shaft 6 andmounted on its projecting end on a cross pin 11 is a disk 12 having a slight rocking movement, as will be obviods from an inspection of Fig. 3, and connected to the disk 12 by two screws 13, Li, is a. milled knob 15 for hand adjustment. The screw 18 is provided'with a milled head for hand adjustment to ell'cct the clutching elf the worm wheel 9 against the collar of t 0' use and permit the disengagement of the worm wheel for lmml adjustment. Both; screws are threaded in the disk 12 and bear against the disk 10, the screw 14 being provided with a nut whereby it may be clamped in adjusted osition. By loosening the .screw 18 the isk 12 will tilt sulliciently to also relieve the pressure of the screw 14, and when tightened both screws press .equally on the disk.

The worm gear!) is driven by means of a ve 8 when the power adjustment is worm 16 rotatably mounted m a bracket 25 away from the shaft (l. The bracket25 is clamped to a sleeve 26 loose on thesllaft adjacent the sleeve 8. The sleeve 26 is held against rotation by means of a fork 27 pivotally connected to the sleeve and engaging a a fixed projection 28 at its lower end.

The worm 10 is driven through'a-uni- .versal joint from a shaft ill" formed of two telescoping parts and connected at its lower end through a second universal joint with the driven shaft of the speed control device 14'. This'devicc per se forms no part of the present invention being covered by my copending application, Serial No. 829,779, filed April 6, 19H, but for the sake of clearness I have shown its essentials in Fig.

As shown in Fig. 2 and more in detail in the drawings in said copending application, 15" represents the driven shaft to be constantly driven and 16" represents the driven shaft which is connected to the driving shaft to drive the clutch whenever the speed of the driven shaft exceeds a predetermined maximum. To effect this connection the driving shaft is provided with a worm, not shown, but driving the worm gear 17 loose on the driven shaft and provided with a beveled gear which connects through a planet gear 18 with a second beveled gear fast to the shaft 10'. The planet gear 18 is supported by a cage 19 which is free to rotate on the shaft 16' except when it is locked against rotation by a centrifugal mechanism driven from the driving shaft. This mechanism comprises centrifugal weights 20 whose outward movement upon the excessive speed of the shaft thrusts a awl 21 into engagement with looking proections carried by the cage '19. When the pawl is disengaged the cage 19 revolves idly around the shaft 16' without driving the shaft, but when the cage is locked by the excessive speed of the driving shaft, the pinion 18 acts as an idler for transmittin the full power of the shaft 15" to the sha 16, as will be readily understood. As explained in my co-pending application above referred to, this mechanism. is extremely sensitive to the slightest change in speed of the shaft 15', and the device can be adjusted to vary the critical speed at which the driving connection .takes place. For combining this mechanism with an electric are 1 conneet the shaft 16 asdescrihed to the carbon adjusting shaft and the driven shaft 15 to the shaft of an electric motor 22 preferably supported as shown on the rod 23 carried in a suitable base plate and providing a support for the casing of the speed controller 14', whereby the motor shaft and control shaft may be maintaincdinalinement.

The electric mdtor 22 is connected as a shunt across the terminals of the lamp, or to the wires thereto. Assuming operating conditions. a certain size of arc-or gap between the carbons-will impress a certain voltage on the motor terminals resulting in a certain speed of the motor, a larger gap increasing this voltage and motor speed, a snmller one rediicing the same.

'lhe adjusting screw 24, as described in my previous application which projects from the end of the cover of the controller, regulates the criticalspeed of the latter, which maybe set to represent the motor speed which will be produced by any desired size of arc.

The operation of' the mechanism will be understood from the foregoing description. As the carbons lmrn away in the production of the light and the gap' of the arc gets larger the resistance through the carbons will be increased thereby-causing more of the current to he shunted through the electric motor with a corresponding increase in speed of the motor. As the normal speed of the motor is just below the critical speed of the controlling device. the slight inc ease. in speed will cause the weights 20. to'fly out aml operate the pawl 21 thereby connecting the driven shaft of the device to the shaft 16, rotating the shaft in the direction to turn the adjusting, shaft through the connection described to bring the carbons nearer together. Bringing the carhons closer together of course reduces the resistance through the are which will reduce the current through the motor so that the speed of the motor falls and when the carbons are back to their position of maxinnnn brilliancy the speed of the motor shaft will once more be below the critical speed of the speed controlling device, and the locking p'awl will release the cage thereby disconnecting the adjusting mechanism from the motor shaft leaving the carbons in thetr properly adjusted position.

As explained above the mechanism of the speed controller is very sensitive in operation, so that an increase of resistance of the are, imperceptible to the eye, willcause the adjusting mechanism to res vond and give a slight movement to the ear ons.

As described in my copending application above referred to my improved s eed control mechanism may be double acting in its operations, that is. it may be designed to connect the power shaft to the driven shaft for reverse operation upon the speed of the power shaft falling below a predetermined minimum, which mhle acting mechanism while not necessary for an are light under ordinary conditions would beuseful to prevent the carbons bein brought too close together through accitental fluctuations in the current not under the control of the operator.

Having thus described my invention, what I claim and desire to secure by Letters Pat ent is: y j

1. In electric arc control mechanism, the combination comprising a pair of electrodes adjustable toward and from each other, gearing for adjusting said electrodes, a normally stationary shaft for actuating said 'aring, means for operating said gearing iy haml. including a sleeve fixedly mounted upon said shaft aml having a frictional rollar at its inner end, a worm gear loosely mounted on said sleeve, adapted to frictionnlly engage with its lateral face the lateral face of said collar, a disk member also lmsely mounted on said sleeve and slidable lhcl'con, arrun ed to normally engage the opposite latera face of said worm gear, a second disk member capable of limited rocking movement but incapable of longitudinal movement, mounted on said sleeve beyond the first disk member, a single adjusting screw for frictionally connecting and dis-- connecting said disk members 0 eratively with said worm gear, and means or actuating said shaft by hand when said disk members are operatively disconnected from said worm gear.

2. In electric arc. control mechanism, the combination comprising a air of electrodes each provided with a ruckar, a pinion for relatively adjusting the said electrodes, a

normally stationary shaft for actuatin' said pinion in circuit with said electr es, a shaft for operating said pinion and provided with a hxed sleeve halving a friction colenga lar at its inner end a worm loosely mounted on said sleeve and adaited to frictionally with its lateral lace the lateral face of said collar, a disk member also loosely and slidably mounted on said sleeve arranged to normally engage the ()PFositc lateral face of saidworm, a second dis member capable of limited rocking movement, but incapable of slidablemovement mounted on said sleeve beyond the first disk member, a single adjusting screw for frictionally operatively connecting, and disconnecting the said disk members with said worm and means for actuating said shaft by hand when said disk members are operatively disconnected from said worm.

Si ed at New York, in the county of New ork and State of New York, this 19th day of October, 1914.

HAYDN M. BAKER, J n.

Witnesses;

L. E. Jomzs'ron, M. E. Evnmzw.

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