US1875814A - Color screen control - Google Patents

Description

Sept. 6, 1932. J. H. KLIEGL COLOR SCREEN CONTROL Filed April 27. 1929 2 Sheets-Sheet l vwmdo'e JOHN H- /fL/EGL Sept. 6, 1932. J, H, KUEGL I f 1,875,814

COLOR SGREEN CONTROL Filed April 27, 1929 2 Sheets-Sheet 2 FIG..

Patented Sept. 6, 1932 UNITED STATES PA-TENT OFFICE JOHN H. KLIEGL, 0F NEWY RK,

N. Y., ASSIGNOR TO KLIEGL BROS. UNIVERSAL ELEC- TRIC STAGE LIGHTING 00., INC., 01? NEW YORK, N. Y., ACORIPORATION OF NEW YORK I COLOR SCREEN common Application filed April 27, This inv ention pertains, to spot lights of the kind used in theatres, and is devoted par-,

ticularly to the apparatus and methodfor controlling color screens usedin connection with such lights. The invention is an improvement onthe invention described in my Patent No. 1,67 9,361, issued August 7, 1928, which discloses electro-magnetic mechanism by which an operator at a distance may manipulate the screens. 7 y

Broadly, the control mechanism comprises a solenoid, which when energized throws a screen to operative position'and holds it there against the resistance of a spring, until the magnet is deenergized, whereupon the spring will return the screen to normal inoperative position.

In order to prevent too rapid movements of the screens and undue slamming of the A screens against their stops, it has been necessary to restrict the power of the solenoids and to use an arrangement of balanced springs, which on the one hand helped the magnet to start the screen in motion, and on the other hand helped to retard the screen during the final stage of its travel. Such arrangements work well when the springs are properly adjusted and when the torque of the solenoid is always the same. However, it often happens, due to conditions on the supply line, dirt on contacts, etc., that the magnet does not act normally and trouble results. If the magnet is so designed as to have ample power when the voltage is low it will have so much power when the voltage is normal that violent action of the screws results.

The object of the present invention is to provide a magnetic control apparatus which will have ample power under any line conditions, which will not slam the screens under any conditions, and which does not require the use of carefully adjusted springs.

Further and other objects and advantages will appear from the specification and drawings which by way of illustration show what is now considered to be the preferred form of the invention.

In the drawings, 7

Fig. 1 is a side view of the spot light with .1929. Serial No. 358,540.

the electromagnetic,control mechanism assembled'thereon. v I

Fig. 2 is'a cross-section 'on the ,line'2-2 of Fig. 1. r

Fig. 3" is a cross-section on the line 3-3 ofFig.1. I i

Fig. 4 is a cross section on the line 44 of Fig. 1.

Fig. 5 is-an enlarged detail view of the re turn spring control, on the line 5-5 of Fig. 4. Fig. 6 is a circuit diagram. i In the drawings 10 is the spotlight, to the side of which is bolted a box-like hous: ing or frame 12 which supports the entire screen control mechanism. Four screens 14 are shown, eachjbeing secured by a clamp 16 to one of theconcentric shafts 18, 20, 22, 24, which are supported for rotationjin brackets 26 on the upper part of frame12. Each screen is balanced about its axis by afweight f 28 on the opposite side of its shaft.

Moun-tedon frame 12 are four solenoids 30, the plunger 32 of each solenoid being connected by a link 34 to a crank arm 36 fast on one of the shafts 18, 20, 22, 24, in such I manner that when any solenoid 30 is ener-' gized its plunger 32 is drawn down, one shaft is rotated, and the screen; 14 attached to the other end of that shaft ismoved from its inoperative: position as shown in Figs. 2 and 3 to its operative position in front of the spot light, and is held there so. long as the magnet is energized. Padded rods .38

and-40 act as stops for the screens while in operative and inoperative position, respectively. When the magnet isdeenergized the screen; is returned to normal position byoits spring 42. The spring arrangement will be understood from Fig. 5. One end of the torsion'spring is attached by screw 44 to a brac'k: et 26, while the free end of the spring is attached to acollar 46 fast on-shaft 18. The spring tends to rotate shaft 18, and its attached screen 14, always toward inoperative position of the screen. A 1

Collar 46 is of non-canducting material, and carries a contact ring 50, intwo semicircular sections, as shown in Fig.v 6, the. two sections being. entirely out of electric contact with each, other. With the abovein net receives the full line voltage and is strongly energized, with the further result that the screen is positively started toward its operative position. However, as soon as the screenand its shaft begin to move, ring 50 is rotated so as to interpose an insulated gap'between spring contacts 66 and68, with the result that all the current must flow through resistance 62, and the torque of the solenoid is reduced accordingly with the result that the screen is delivered softly in inoperative position. WVh-en key 52 isreleased the screen is returned to normal'position by its spring 42. I V

This invention has been found verysatisfactory in practice. The. screen is always started positively even with very low line voltage,'and is always deposited softly in operative position even with high line volt-age.

'It is to be understood that the invention is not limited to the specific embodiment herein described but can be used in other ways without departure'from its spirit as defined by the following claims.

' 1. A color controlapparatus for a spot light, comprising in combination, a color screen having normal and operative positions,asolenoid operatively connected to said screen, means for supplying current to said solenoid whereby said solenoid rotates said screen from normal to operative position, and

' means effective immediately after said rota tion begins, for'producing and maintaining a constant reduction in strength of said solenoid, whereby said screen is moved softly positively to operative position.

2. A'color control apparatus for a spot light, comprising in combination, "a color screen having normal and operative posi-.

tions, a solenoid operatively' connected to said screen, means for supplying current at comparatively high voltage to said solenoid whereby said solenoidrotates said screen from normal toward operative position, and means for automatically producing and maintaining a constant but reduced voltage through said solenoid after the rotation of the screen has started, for th'e'purpose set forth. 1

- 3.-A color control apparatus for aspot light, comprising'in combination, a color screen having normal and operative positions, a solenoid operativ'ely connected to said signature.

screen, a resistance, a contact member, means for supplying current to said solenoid through said resistance and said contact member in parallel whereby said solenoid rotates said screen, and means efiective while rotation is taking place for breaking the circuit through said contact member and thereby causing all the current to flow through said resistance, wherebysaid solenoid is sup plied with a constant but weakened current, for the purpose set forth.

4. The method of operating a color screen for. spotlights which consists in initiating a movement of the screen in front of the spotlight against a gradually increasing resistance with a substantially constantmoving force considerably greater than the maxicome the resistance at its maximum.

In testimony whereof I hereto aflix' my JOHN H. -ianinon W V V V V V V 7 CERTIFICATE OF CORRECTION.

Patent No. 1,875,814. September 6, 1932.

JOHN H. KLIEGL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 96, for the misspelled word "non-eanducting" read non-conducting; page 2, lines 22 and 23, for "inoperative" read operative; and that the .said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of November, A. D. 1932.

M. J. Moore, (Seal) Acting Commissioner of Patents.

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