US2023475A - Automatic feed for high intensity arc lamps - Google Patents

Description

F. R. HOUSE AUTOMATIC FEED FOR men INTENSITY ARC LAMPS Dec. 10, 1935 Filed June 26, 1933 4 Sheets-Sheet 1 WW m5 ATTORNEY Dec. 10; 1935. H U E 2,023,475

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AUTOMATIC FEED FOR HIGH INTENSITY ARC LAMPS Filed June 26, 1933 4 Sheets-Sheet 3 INVENTOR Q firm/K 47/81/55. 8 I50 Mun Dec. 10, 1935. F. R. HOUSE AUTOMATIC FEED FOR HIGH INTENSITY ARC LAMPS Filed June 26, 1933 4 Sheets-Sheet 4 INVENTOR fimlvn fl. #0055.

Patented Dec. 10, 1935 UNITED STATES AUTOMATIC FEED FOR HIGH INTENSITY ARC LAMPS Frank 1;. House, Baldwin Harbor, N. Y., assignor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation of New York Application June as, 1933, Serial No. 677,644

10 Claim.

This invention relates to automatic arc lamp mechanisms especially adapted for searchlights of the high intensity type. More particularly it relates to improvements in the operating mechanism therefor and in the construction of the positive and negative electrode holders and feeding means whereby greater reliability and simplicity are secured andquick recarboning rendered possible.

Referring to the drawings showing the preferred form of my invention,

Fig. 1 is a side elevation of the complete lamp box structure showing a simplified wiring diagram in connection therewith.

Fig. 2 is a detail of the auxiliary hand rotating means for the positive electrode.

Fig. 3 is a detail of the star wheel feeding mechanism for the positive electrode. 7

Fig. 4 is an enlarged side elevation, partly in section, of the positive head and feeding mechanism.

Fig. 5'is a plan view with the cover removed of the lamp box or base.

Fig. 6 is an enlarged detail showing the hand control of the positive feed.

Fig. 7 is a side elevation of the negative head.

Fig. 8 is a vertical section through the rotating axis of the negative feed gears and rollers.

Fig. 9 is a top plan view of one of the positive feed rollers and its supporting carriage.

Fig. 10 is a side elevation, partly in section, of,

the interior of the lamp box.

Fig. 11 is a transverse section through the same.

Fig. 12 is a front view of the negative head.

Fig. 13 is a diagram illustrating the pawl action of the negative feeding means.

Fig. 14 is an end view, on a larger scale, of one of the squared shafts on which the feed gears and pinions are mounted.

The positive electrode holder l and the negative electrode holder 2 are shown as supported on a common standard 3 rising from the lamp box 4 on the sides of which are lugs 5 slidably mounted in trackways 5 at the base of the searchlight drum 6. Preferably the standard 3 is made hollow and cooling air passes up through the same and through the hollow nose cap I and out through aperture 8 to cool the nose cap and ventilate the drum. The positive current is preferably carried up through the standard 3 and is introduced into the positive electrode 9 through spring pressed semi-circular ribbed brushes I0, the upper brush being held against the electrode by springs H and current being led thereto through flexible lead I2, Preferably the nose cap l is insulated from the positive holder by insulating disc I3 and insulating washer I4 to prevent the are from leaving, the positive electrode and striking over to the positive holder in case the electrode burns back.

The feeding mechanism is preferably placed to the rear of the brushes l0 and is also preferably insulated therefrom, the feeding mechanism being shown as mounted on a bracket insulated from the standard 3 by insulating disc l6 and 10 insulating bushing l'l. Within said bracket is journaled a sleeve I8 which is rotated bodily from a large bevel gear I9 secured thereto. On the face of said sleeve is mounted a bracket 20 to which is pivoted at 2| and 22 respectively a pair of feed roller carriages 23 and 24. Carriage 23 has journaled therein a shaft 24 on which is mounted a feed roller 25 and a driving gear 26. Similarly the carriage 24 has shaft 21 journaled therein carrying a lower feed roller 30 and a driving gear 3| meshing with the gear 26. Said brackets are pressed yieldingly together by a tension spring 32. Gear 3| is shown as rotated from a pinion 33 on the shaft 34 of a wormwheel 35, the axis of said shaft being coincident with the aforesaid axis 22'. wormwheel 35 is shown as driven from a worm 35, on the shaft of which is mounted a pinion 31 meshing with a gear 38 pinned to the face of a star wheel or cam disc 39, said disc being frictionally mounted on said sleeve I8. When the gearing I9 is rotating normally, all partssecured thereto revolve together without feeding the electrode. In case, however, the star wheel 39 is prevented from rotating for a period as by means of'the projection of shaft 40 into the path of the star wheel, said wheel will be held stationary thereby causing pinion 31 to revolve on its own axis and thereby effect feeding of the electrode as long as the star wheel is so held.

For recarboning, I have shown the pivoted rocker arms 23 and 24 as provided with rear-' wardly extending lugs 4| and 42, the ends-of which lie adjacent each other in the path of a cam 43 secured to the shaft 44 of a thumb piece 45 44. By rotating the thumb piece, the cam is pressed against said rocker arms and opens both arms, thus freeing the positive electrode.

Normally the positive electrode is continuously rotated by a pinion 45 meshing with bevel gear I9 and which is driven from a motor 46 in the lamp box through shaft 41 and gearing 85, 86, 89 and 9]! as hereinafter explained. If the motor fails, the electrode may be revolved by hand through the bevel pinion 50 on shaft 5| which is connected by a universal joint 52 to a handle (not shown) outside of the drum. Pinion 50 is shown as meshing with pinion 5| on the shaft of pinion 45. The position of the stop pin or shaft is preferably controlled by the position of the arcing face of the positive electrode in the usual manner, 1. e. by a beam from thearc directed by a lens 52 onto a thermostat 53 which controls a circuit through the magnets 54 to attract armature 55 pivoted at 56 and thus raise the outer end thereof 51 on which rests the lower end of rod 40, said rod being normally yieldingly pressed downwardly by spring 56. In operation the rod is alternately raised and lowered, i. e. slowly reciprocated, since when raised the rate of feed is much faster than normally required.

As stated above, the feed roller carriage is preferably insulated from the positive head. I provide, however, an auxiliary path for the current on the positive side of the line from said insulated carriage through flexible lead 51 and through the rod 40 to one'side of the voltage control coil 58 which controls the negative feed. As long, therefore, as the proper length of electrode is in the holder, current will pass through the electrode and through the feed roller carriage to saidcoil 58, but when the electrode burns down so short that the end leaves the feed rollers so that no further feedingican take place, this shunt path of the current is interrupted thus breaking the current through the coil" 58 and causing a rapid withdrawal of the negative electrode and extinguishing the are as hereinafter explained. By this or equivalent means, an automatic arc extinguishing means is provided which is brought into operation when the positive electrode becomes too short.

The negative holder is shown as comprising a 7, pair of upper and lower jaws 68 and 6|, the upper jaw being pivoted about a sleeve 62 (Fig. 8) journalled in a bracket 62 extending from fixedsupport 6| of jaw 5|, so that it may be raised to the dotted line position in Fig. 7 for recarboning, current being led to the upper jaw through flexible leads I20 and I 2|. I Said electrode is fed by the rotation of feed shaft 63 driving the bevel gear 84 through universal joint 65. Said bevel gear drives in turn the bevel gear 66 secured to a shaft 61 journaled in the main framework BI and within the sleeve 62. On said shaft 81 is mounted a pinion 68 meshingwith pinion 69 on shaft 10 of the lower feed roller H, the upper feed roller .12 being driven from pinion 13 meshing with pinion 69. For releasing the electrode there is shown an operating lever 14 pivoted at 15 on upper jaw 60. A stiffelbow spring 16 is connected between a point 11 on the fixed holder GI and a point 18 on the lever 14, so as to hold lower end of the lever upwardly and outwardly in the direction of the dot and dash line. A limit stop is provided by the top 19 contacting with the rear portion of jaw 60 to prevent binding of gears 13-69 in case an undersize carbon is used. Also secured to said lever is apair of brackets 8i in which is journaled the shaft 82 of the feed roller 12. The framework 60 is provided with an ovalopening 83 surrounding the feed roller. When the lever 14 is pressed inwardly, therefore, the first action is to lift theupper feed roller 12 out of contact with the electrode. Further movement of the lever brings the feed roller into'contact with the upper part of the elliptical hole 83 so as to lift the entire jaw 60 about the sleeve 62 as a a pivot. The distances a, b, c and d are so proportioned that a greater pressure is exerted on the feed rollers than on the clamping jaw 60 so that the positive feeding action is assured even though the spring tension varies because the pressure ratio remains fixed. It should be noted that feed roller shafts 81, Ill and 82, 24 and 21 in the nega- 5 tive and positive heads are preferably partially squared, providing both flattened surfaces I80 (Fig. 14) and rounded surfaces i3 i Such a shaft will drive the pinions and feed roller without keying or pinning so that they may be readily re- 10 moved, and also such a shaft rotates freely in an ordinary hearing. In fact it is superior to a plain shaft since it is self-cleaning and will scour grit and dirt out of the bearing.

The motor 46 operates both the positive and 5 negative feeding mechanisms as follows: On the shaft of said motor is shown a worm 85 driving a wormwheel 86 loosely mounted on shaft 81' (Figs. 10 and 11). A one way, spring pressed clutch 88 is provided to connect the wormwheel and shaft. 20 Said shaft is shown as driving the shaft 41, which rotates the positive electrode, through bevel gears 89 and 90. Onsaid shaft isalso mounted a crank pin 9i which engages a sliding block 92 in oscillating arm 93 pivoted at 94. The upper end of 25 said rocker arm is shown as pivotally connected to reciprocate a pawl carriage 95 which is pivotallyconnected as by means of the pin 96 to a rocking lever 91 pivoted to the frameat 88. Also pivotally mounted on said pawl carriage are two 30 spring-pressed pawls 99 and I00 each engaging oppositely rotatable ratchet wheels HH and IN on vertical shaft I02 which is connected to the negative feed shaft 83. For controllingthe pawls there is shown a forked lever I03, the forward 35 end of which lies under the two pawls 89 and I00 (Fig; 5). Whensaid lever is rocked slightly in an upward direction, for instance in Fig; 5, the pawl 99 is held out of engagement with its ratchet and pawl I00 permitted to engage with its ratchet 40 so that shaft I02 will be driven in one direction while the reverse action takes place if the lever I03 is moved downwardly. Said lever is shown as pivoted at I06 adjacent the voltage control electro-magnet 58 which is opposed by the spring 4'5 I01 so that the negative electrode is fed in either direction required to maintain the proper voltage across the arc and, therefore, to maintain the proper arc length. Preferably the rate of feed in bothdirections is varied in accordance with 50 the departure of the voltage drop from normal so that a rapid rate is secured for striking and drawing the are. This is secured readily by varying the period of engagement of each pawl with its ratchet so that the angle through which the 65 ratchet is turned per stroke is varied. .In this connection I prefer to have thenormal stroke of each ratchet tooth lie to the near side of the center line 0-0 of the ratchet wheel Hll (see Fig. 13). In this figure the normal stroke of the 60 ratchet teeth is represented as between the points P and P, the center of the stroke being at C. If the path of the ratchet is represented by the line PP, it will readily be seen that when said line is about tangent to the circle 10!, the ratchet 65 wheel will be moved through the distance 0-? and that as said line PP' is lowered, the angle through which the ratchet is turned is rapidly increased, for instance, from the angle P'-C'O to PC--E., Also, by designing the pawls in 70 this manner, there is no tendency for the pawl to hang on a tooth since the pawl is disengaged from the tooth always at or near the end of the stroke. Preferably also the hinge I06 is substantially in line with pivot 96 so that normally the 75 I parallel edges of fork I 83' are in line with the direction of movement of the pawl carriage. This .avoids hunting and assures smoother operation.

It should also be noted that I have eliminated longitudinally reciprocatory parts requiring open or flat sliding bearing parts in my negative feed mechanism. Thus, although the pawls are reciprocated, the carriage 95 has no open or flat bearing but is hinged by an ordinary radial bearing on the link 91 which, in turn, is hinged in a similar bearing 98. Such bearings are easily lubricated and do not collect dirt and grit and, therefore, operatemuch more satisfactorily than ordinary sliding bearings.

Hand control of the negative feed may be effected by the push button I08. When in the position shown in Fig. 11, the hand control is operative since the bevel gear I09 on the shaft of button I08 is in engagement with bevel gear H0 on shaft [02. At this time also an arm III is rotated clockwise to the position shown to bring the V-shaped notch H2 into engagement with the centralizing pin H3 on arm I03 and thereby to centralize the arm and hold both pawls out of engagement. When the push button is pushed in, however, gears I09 and I III are disengaged and V-shaped notch H2 is moved counterclockwise out of engagement with the pin H3 so as to release the lever for control by electro-magnet 58.

The positive feed may also be controlled from thumb piece H5, the shaft of which, at its inner end, is pinned to a lever I I6 pivoted at Hl on the casing. At its upper end said lever is pinned to a longitudinally extending rod H8 which has thereon a cam plate H9. Said plate, when the rod is pushed inwardly, engages the top of the pivot armature 55 (see Fig. 6) so as to force the outer end of the armature upwardly and thereby lift the pin to engage the starwheel 39 and thereby causing rapid and continuous feeding of the positive carbon until the thumb piece H5 is pulled back again, upon which the automatic feed under the control of the thermostat is resumed.

It should also be noted that my lamp may be operated easily entirely by hand in case of failure of the motor 46. Thus, the turning of the shaft 5| by hand not only rotates the positive head but also through shaft 4! it operates the oscillatory rocker arm 93 by turning the shaft 81 through bevel gears 89 and 90. This is rendered possible by the slippage of the one way clutch 88. Therefore, if the arc is otherwise operating, the negative electrode will be fed to maintain the arc length through the regular pawl and ratchet mechanism 99, I8I and the positive feed will likewise be automatic by the operation of the thermostat in lifting the rod 40. Also, as explained above, each feed may be independently hand operated in case of failure of either.

On account of the varying resistance of the negative feed coil 58 with temperature changes, I also prefer to compensate for the same by placing a relatively high resistance 58' in series therewith which has a flat or negative temperature resistance coeflicient so that the overall resistance will not change materially with temperature.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only 11- lustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a feeding and rotating means for electrodes, a rotatably mounted sleeve for receiving the electrode, a plurality of feed rollers journalled on said sleeve to revolve therewith, a gear fricl tionally mounted thereon, a pinion meshing therewith journalled on said sleeve and having a driving connection with said feed rollers, means for interrupting the rotation of said gear tocause rotation of said pinion on its axis to rotate said 1 rollers on their own axes to feed the electrode as it is rotated, means controlled by the position of the arc tip for reciprocating said means for normal feed, and manual means for raising said means for continuous or steady feed. 2

2. In a feeding and rotating means for electrodes, a rotatably mounted sleeve for receiving the electrode, a plurality of feed rollers journalled on said sleeve to revolve therewith, a gear fric-' tionally mounted thereon, a pinion meshing there- 2 with journalled on said sleeve and having a driving connection withsaid feed rollers, means for interrupting the rotation of said gear to cause rotation of said pinion on its axis to rotate said rollers on their own axes to feed the electrode as 3 it is rotated, means controlled by the position of the arc tip for reciprocating said means for normal feed, manual means for raising said means for continuous or steady feed, and alternative power means and manual means for rotating said 3 sleeve.

3. In a feeding and rotating means for electrodes, a rotatably mounted sleeve for receiving the electrode, a pair of brackets pivotally mounted thereon, a feed roller journalled in each brack- 4 et, yielding means for pressing said rollers into engagement with the electrode, an arm on each bracket, and a manually operable cam journalled on said sleeve for engaging both arms to spread the feed rollers for recarboning.

4. In a two way feed for electrodes, 8. feed shaft, a pair of opposite ratchet wheels thereon for turning said shaft in either direction, a reciprocatory carriage, a pair of pawls thereon, the

stroke of which lies mainly on the near side of said ratchets, radially movable means for holding both pawls out of engagement with their ratchets, but permitting greater or less engagement of either pawl with its ratchet upon greater or less radial movement of said means, and means controlled by the voltage drop across the are for positioning said means whereby a variable rate of feed in either direction is obtained in accordance with the departure of the arc voltage drop from normal.

5. In a two way feed for electrodes, a feed shaft, a pair of opposite ratchet wheels thereon for turning said shaft in either direction, a reciprocatory carriage, a link supporting the same providing a radial bearing support, a pair of pawls on opposite sides thereof, one for each ratchet, a fork adapted in its central position to hold both pawls out of engagement with their ratchets, and

means responsive to the arc length for moving for turning said shaft in either direction, a reciprocatory carriage, a pair of pawls ontopposite sides thereof, one for each ratchet, a hinged fork which in its central position holds both pawls out of engagement with their ratchets, the hinge thereof being substantially in line with the path of movement of said pawls, and means responsive to the arc length for moving said fork about said hinge to allow the proper pawl to engage its ratchet to maintain the proper arc length.

7. In a projector lamp, feeding means for maintaining the arcing face of one electrode in a fixed position, and means for feeding the other electrode in accordance with the voltage drop across the are including a voltage coil across the main arc circuit and a high resistance in series therewithand having a non-positive temperature resistance coeflicient.

8. In a feeding means for the electrodes ofa searchlight and the like, the combination with the positive and negative electrode holders, of current introducing brushes on the positive holder near the arc, feeding rollers thereon to the rear of said brushes and insulated therefrom, means for actuating said rollers to maintain the positive electrode in the focus of the searchlight, means for feeding the negative electrode in both directions, a winding controlling the direction and speed of said negative feeding means, and a circuit from the positive electrode through said feed rollers and winding, whereby when the positive electrode advances beyond said feed rollers the circuit to said winding is interruptedand the 5 negative electrode withdrawn to break the are.

9. In an electrode holder for searchlights and the like, current introducing brushes thereon near the arc, feed rollers to the rear of said brushes and insulated therefrom, a shunt circuit from the electrode through said feed rollers, and means operable by the interruption of current through said circuit for extinguishing the arc;

10. In a feeding means for the electrodes of arc lamps, a plurality of electrode griupping feed rollers having squared central openings therein, pinions for driving the same also having squared central openings therein, partially squared shafts having rounded corners on which said rollers and pinions are mounted, whereby the former is driven from the latter, and plain bearings for said shafts, whereby'said shafts may be rotated in their bearings by said pinions and said rollers rotated from said shafts, and whereby both said pinions and rollers may be readily removed from said shafts when desired.

FRANK R. HOUSE.

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