US964665A - Starting device for electric lamps. - Google Patents

Description

G. M. LITTLE.

STARTING DEVICE FOR. ELECTRIC LAMPS.

APPLICATION FILED MAY 6, 1907.

964,665, Patented July 19, 1910.

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G. M. LITTLE.

STARTING DEVIGE FOR ELECTRIC LAMPS.

APPLICATION nun MAY 6, 1907.

964,665, I Patented July 19, 1910.

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WlTNESSES: INVENTOR G. M. LITTLE.

STARTING DEVICE FOR ELECTRIC LAMPS. urmonxon I-ILED MAY 6, 1907.

964,665. I Patented July 19,1910.

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UNITED STATES PATENT OFFICE.

GEORGE M. LITTLE, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC &. MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING DEVICE FOR ELECTRIC LAMPS.

To all whom it may concern.

Be it known that I, Gnonon M. LITTLE, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Starting Devices for Electric Lamps, of which the following is a specification.

My invention relates to are lamps, and particularly to lamps in which insulating deposits or bodies of slag sometimes form upon the electrodes and interfere with ready starting of the arc.

The object of my invention is to provide an especially eifective means for causing the electrodes of a lamp to be moved into and out of engagement until the insulating materials that may have been deposited thereon have been removed in order to permit of starting the arc.

Arc lamps are now frequently provided with electrodes containing materials that render the same less readily consumable and capable of producing arcs of greater luminosity than ordinary carbons, one suitable composition comprising the magnetic oXid of iron (Fe O as the predominant con stituent, which gives conductivity to the electrode both when hot and when cold, chromium OXlCl (010,), which, by reason of its very high fusing point, assists in preventing rapid consumption of the electrode and flickering of the arc, and titanium oxid (TiO or another compound of titanium, which imparts color and brilliancy to the arc and also assists in prolonging the life of the electrode. In the use of such electrodes, fumes and bodies of insulating slag composed largely of non-conducting oxids, sometimes form upon the electrodes and interfere with ready establishment of the are by preventing good electrical contact between the electrodes when the same are brought into engagement. In order to remove such slag and fumes and to thereby improve the electrical contact between the electrodes, it has been proposed to move the electrodes rapidly into and out of engagement until the arc is established. The devices that have heretofore been employed for this purpose have been uncertain and otherwise unsatisfactory in operation, and it is the object of the present invention to Specification of Letters Patent.

Application filed May 6, 1907.

Patented July 19, 1910.

Serial No. 372,179.

provide suitable and inexpensive means that shall be more effective and certain in operation than the said prior devices.

Figure 1, of the accompanying drawing, is a view in front elevation of a portion of a lamp embodying my invention. Fig. 2 is a view in side elevation of the parts shown in Fig. 1. Fig. 3 is a diagrammatic view of the circuits of a lamp embodying the invention. Figs. 4; and 5 are enlarged views of some of the parts of the lamp that illustrate more clearly the mode of operation of the invention.

Electrodes 1 and 2 of an arc lamp, either or both of which may be composed of the oXids above specified or of other suitable materials, are normally maintained out of engagement by means of a clutch 3. The clutch is adapted to be operated by means of a rod 4, the upper end of which is secured to a movable magnetizable core 5 of an electro-magnet winding 6, the core 5 being normally supported in its uppermost position by means of a spring 7 The electro-magnet winding 6 is. connected in series with a suitable resistance 8 between one terminal 9 of the lamp and a stationary contact terminal 10, an adjacent stationary contact terminal 11 being connected to the terminal 12, of the lamp. Contact terminals 10 and 11 are adapted to be bridged by means of either the one or the other of two movable switch members 13 and 14, the latter of which is normally out of engagement therewith.

The switch member 13 is provided with an operating magnet winding 15 that is connected between the electrode 1 and the terminal 12 of the lamp, and serves to raise the switch member 13 out of engagement with. the contact terminals 10 and 11 when the electrodes 1 and 2 are in electrical contact or when an arc exists beteween them.

The switch member 1 1 is provided with an operating magnet winding 16 that has its respective terminals connected to the electrodes 1 and 2 and serves to move the switch member 14L into engagement with the contact terminals 10 and 11 when the difference in potential between the electrodes 1 and 2 rises above a predetermined limiting value.

A circuit in shunt to the electro-magnet winding (3 is governed by means of the device constituting the subject matter of the present application, said device comprising cooperating resilient switch members 17 and 18, the former of which is of substantially U-shape and is carried by a longitudinally mo *able bar or red 19 mounted in guides 20 formed in the extremities of a U-shaped bracket 20 that is secured to any convenient stationary portion of the lamp. The bar 19 is caused to reciprocate by means of a forked arm 21 that is carried by the core 5 or by some other convenient portion of the lamp that operates synchronously with the said core. The forked end of the arm 21 em braces the upper screw threaded end of the bar 15) upon which two nuts 23 and Q-l are threaded for the purpose of providing an adjustable stop. The reciprocating motion of the bar 19 may be delayed in both directions of movement (though preferably only the downward movement is delayed) by means of a dash-pot or other suitable retarding device 25 the respective members of which are attached to the lower end of the bar 19 and to a stationary part of the lamp. The upper end of the switch member 18 is secured to, but insulated from, the bracket 20, an adjustable stop, against which the resilient switch member 18 normally rests, being provided in the form of a screw 26 threaded into an insulating block 27 that is attached to the U-shaped bracket 20.

In order that the switch members may be prevented from engaging during the downward movement of the switch member 17 until the said member has very nearly reached its lower limit of movement, and also in order that the switch members may be maintained in engagement during a considerable portion of the upward movement of the switch member 17, an inclined guide 28 is interposed in the path of movement of the extremity of the member 17, the guide and the extremity of the switch member being so shaped and adjusted with respect to each other that during the downward movement of the switch member, the latter engages the back face of the guide and during the upward stroke it engages the front face of the guide.

lVhen current is first supplied to the lamp, it traverses the resistance 8, electro-magnet winding (3, and switch member 13. The electro-magnet winding (5, being thus energized, causes the core 5 to be drawn downward in opposition to the tension of the spring 7 and the electrode 1 is thus caused to engage the electrode 2. If the ends of the electrodes are wholly or partially covered by a high resistance slag, or with other insulating deposits, formed during the operation of the lamp, the resistance thereby interposed between the electrodes may be so great as to prevent establishment of an arc. However, the downward movement of the magnet core 5 and the attached arm 21 permits the bar 19 and the parts associated therewith to move downward also, the downward movement of the latter parts being retarded by means of the dash-pot lVhen the switch member 17 is released by the guide 28, near the lower limit of the stroke, it engages the member 18, and the magnet winding (3 is thereby shunted. The core 5 with the rod l, the clutch 3 and the electrode 1 are thereupon raised by the action of the spring 7, the switch members 17 and 18 being maintained in engagement by means of the guide 28 until. the electrodes have been separated a predetermined distance.

When the switch members are permitted to disengage, the shunt circuit to the winding 16 is interrupted, and the core 5 with the attached parts will be again drawn downward against the action of the spring 7, the electrodes being thereby caused to reengage. The operations just described will continue successively until the deposits or slag upon the electrodes are displaced and partially or wholly removed and sutliciently good electrical contact between the electrodes is established to permit of starting the are, where upon the switch 13 will open and the lamp will continue in operation until feeding of the electrode 1 becomes necessary. This will be caused by an increase in the difference of potential between the electrodes to such value that the winding 16 may move the switch member 14 into engagement with contact terminals 10 and 11.

The dash-pot 25 is employed for the purpose of delaying contact between the switch members 17 and 18, and consequent separa tion of the electrodes, until the electrodes have been in engagement a predetermined length of time, in order that the small amount of current, which is permitted to pass between the electrodes when the material upon the ends thereof is only poorly insulating, may heat the same and possibly cause starting of the are.

It will, of course, be understood that structurally the device for causing repetition of movement of the electrodes into and out of engagement may assume many varied forms, that shown being one form that has been found operative and practical.

I claim as my invention:

1. In an arc lamp, the combination with electrodes, and means, comprising an electro-magnet winding, for moving the same into and out of engagement, of a switch for shunting the electro-magnet winding, said switch comprising a stationary member and a reciprocatory member actuated by the means for moving the electrodes into and out of engagement, the said members engaging during a port-ion of the movement of the reciprocating member in each direction,

means interposed in the path of the reeiprocatory switch member for preventing the same from engaging the stationary member until near the limit of its travel in one direction, and for maintaining the members in engagement during the first portion of the travel or the member in the opposite direction, and means for delaying movement of the reciprocatory member in one direction.

2. In an arc lamp, the combination With electrodes, and means, comprising an electro-magnet winding, for moving the same into and out of engagement, of a switch for shunting the electro-magnet winding, said switch comprising a fixed member and a reciprocatory member actuated by the means for moving the electrodes into and out of engagement, the said members engaging during a portion of the movement of the reciprocatory member in each direction, means for preventing the reciprocatory member from engaging the fixed member during its travel in one direction except for a small portion of said travel, and for maintaining the members in engagement during a larger portion of the travel of said member in the other direction, and means for delaying movement of the reciprocatory member in one direction.

3. The combination With a stationary switch member and a reciprocatory switch member having a portion inclined with respect to its direction of movement, the said members engaging during a portion of the movement of the reciprocatory member in each direction, of an inclined guide interposed in the path of movement of the reciprocatory member that presents engagement of the switch members during a portion of the travel of the reciprocatory member in one direction and causes engagement thereof during substantially the same portion of the travel of the reciprocatory member in the opposite direction, and means for delaying movement 01 the reciprocatory member in one direction.

In testimony whereofll have hereunto subscribed my name this th day of April, 1907.

GEORGE M. LITTLE.

Witnesses OTTO S. Sormmnn, BIRNEY Hines.

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