US2539228A - Intermittent lighting means for motion pictures - Google Patents

Description

Jan. 23, 1951 w. E. CELESTIN 2,539,228

, INTERMITTENT LIGHTING MEANS FOR MoT1oNP1cTUREs Filed Feb. 18, 1949 2 Sheets-Sheet 2 Patented Jan. 23, 19541 lOFFICE INTERMITTET LIGHTING MEANS FOR MOTIN PICTURES William E. Celestin, New York, N. Y.

Application February 18, 1949, Serial No. 77,220

2 Claims.

My invention relates particularly to a lighting apparatus for providing more effective lighting in projecting motion pictures.

In previous lighting apparatus, as for instance that used in the projection of theatrical motion pictures, there are many inadequacies, among which the most important are the excessive heat generated by the crater of the carbon arc, the re hazard from the open flame of the gas ball of the carbon arc, the difficulty of maintaining uniform luminosity andl screen brilliance for any length of time, and the great loss of the light generated in the lamp house of the Iprojector which does not reach the screen.

In accordance with my invention, these disadvantages are effectively overcome, continual watching of the light source is no longer necessary, and, besides, a more uniform lightand control thereof is obtainable and the fire hazard is eliminated. In fact, the operation thereof is substantially automatic. Further objects of my invention will be seen from the detailed description thereof, hereinafter.

I accomplish this, preferably, by utilizing an evacuated, hollow, vitrious gas envelope containing an inert gas, such as krypton, helium, xenon,

ing on the top thereof a circular casing 2 for a nlm reel 3, carrying therein a iilm 4 to be exhibited, the reel 3 being carried on a central pivot 5, in the usual way. The film 4 is fed downwardly by a sprocket 6 against which two small idlers 'I and 8 are spring pressed by a frame and onto a sprocket I8 onto which it is pressed argon, or other similar noble gaseous filling. o

This is in the form of a cathode'discharge lamp giving instantaneous flashes of light of high intensity synchronized with the pull-down move-, ment and shutter of the projecting machine.

While my invention is capable of embodiment in many different forms, for the 'purpose of illustration I have shown only one form thereof in the accompanying drawings, in which- Fig. 1 is a diagrammatical vertical section of a projecting machine made in accordance with my invention;

Fig. 2 is a diagrammatic illustration of the electrical circuit used together with a vertical section of the light source shown in Fig. 1;

Fig. 3 is a fragmental enlarged side elevation of the said light source, showing the light bulb wheel, taken on a plane at right angles to the axis thereof; i

Fig. 4 is a fragmental enlarged radial section of said wheel; and

Fig. 5 is an enlarged detail of the shutter gearing.

by idlers I9 and 20 on a frame 2ll carried by a shaft 22 on the casing. From this point the lm 4 passes onto a lower reel 23 pivotally supported in the casing I in the usual Way.

For driving the mechanism, there is provided an A. C. motor 24' having leads 25 and 26 leading to the usual house circuit and having a switch 21 in a switch housing 28, for turning the current to the motor 24 on and oil, as desired. The motor 24 has a driving shaft 29, which may have any usual suitable gearing connected to the sprockets 6 and I8 for driving the same in the usual way, not shown. On the shaft 29, furthermore, there is a gear 30 which drives a gear 3l on a shaft 32 carrying a clutch disc 33 to cooperate with another clutch disc 34 splined on a shaft 35 and having the usual clutch lever 36 for throwing the clutch 33, 34 into and out of engagement at 39 which engages with a pin 4D in an' arm 4I having one or vmore teeth or prongs 42 to engage the usual lm perforations, as in the case of Athe usual pull down mechanism, for advancing the iilm one frame at a time. The lower end of the arm 4'I is normally pressed upwardly by a link 43 carried loosely on a fixed stub shaft 44 on the casing I, and carrying a spring 45 having its end attached, respectively, to the link 43 and the shaft 44. The worm wheel 38 is onr a shaft 45 journaled in the casing I, and near one end thereof has a sprocket 41 for driving a sprocket belt 41a carried by a small sprocket 48 on a slidable peripherally grooved shaft 49, on which it has a spline 49h for relative movement of the shaft 4'9,

In the drawings, I have shown a casing I hav- 5o which is supported so as to cooperate with a re- 3 taining ring having a spring pressed ball 49a in a lamp house 50, having four or more ventilation openings The shaft 49 has operating handles 52 and 58 at the end thereof so as to move one or the other of two light bulb wheels 54 and 55, tight on the shaft 49, into position before a conical reflecting light exit 56, located in the bulb housing 59, which registers with the usual cylindrical condenser 51 having one or more condensing lenses 56 to produce parallel light beams to be projected through the film 4 while at rest between the gate openings |5 and I6, and thence through any desired shutter 59, on a shaft 60 carrying a driving worm' 6|, which is located in the rear of an objective 62 of any desired type. The shutter shaft 6| is drivenl in timed relation to the pull down mechanism 4| through the motor from the shaft 45 by a worm 63 on the shaft 46, or any suitable gearing connection, it being immaterial how the gears are arranged providone of the bulbs 4| during the time that the nlm 4 is at rest for projecting one of the frame pictures therefrom and in the time when the next frame picture is being exhibited the next one of the bulbs 8| is being energized However. sufflcient time is allowed to elapse for the build up ing the speed of the shutter and pull down are properly synchronized.

Each of the bulb wheels 54 and 55 is constructed like the other except that the brush contacts are on opposite sides thereof, respecn tively. Consequently, only one of them, the wheel 54, will be described in detail, as shown in Figs. 3 and 4. The wheel 54 is comprised of an outer disc 64 carrying two sets of radial contact plates `65 and 66 of metal separated from each other,

which contact, respectively, with brushes 61 and 68, like similar brushes 69 and 10 cooperating with like sets 1| and 12 on the Wheel 55. All these brushes 61, 68, 69 and 10 are mounted on a slidable insulating flat base 13 having an arm loose on the shaft 49, to cooperate with two stationary contacts 13a and 13b in the housing 50. wheel 54, furthermore, has an inner disc 14, on the shaft 49, secured by a circular parabolic reflector 15 to the outer disc B4 on which the contacts 65 and 66 are carried. Between the two discs 14 and 64 there are secured, on the disc 54 a plurality of pairs of metal U-shaped clips 11 and 18, for instance about twelve such pairs, although any other number can be provided. The inner clips 11 are connected to the contacts 65, respectively, by conducting rivets 19 and the outer clips 18 are connected to the conducting plates 66, respectively, by conducting rivets 80.

Each pair of clips 11 and 18 carries therein a cylindrical glass or quartz tube 8| containing one or more of the rare gases, such for instance as one or more of those rare elements obtained from the air, for example krypton or krypton and xenon. The tube has cylindrical conducting terminals 82 and 83 on the ends thereof within the clips 11 and 18, said terminals being connected to an anode and cathode, respectively, within the bulb 8| to carry the current therefrom through the body of gas which is at any desired vacuum or pressure within the bulb 8|, for instance 1 to 2 centimeters of mercury. The gas contains krypton and preferably carries a. proportion, comprising any desired amount` of* xenon. These bulbs or envelopes can produce flashes of the most intense of all known types of light, for a fraction of a second at least, once their conductivity is established by ionizing the gas with the initial voltage passed through the same. Preferably this initial voltage may be 2000 volts or even higher, after which the gas therein presents substantially no resistance to the further passage of the current therethrough. The gearing 41, 48 is so arranged that there is a iiash from Thel to the initial high voltage after the closing of the brush contacts 61 and 68 for the particular bulb 8l, before said bulb 8| is located opposite the conical reflector 56, when the particular film frame is at rest to be exhibited, but as the said flash is extremely short the flash can take place at any time or portion thereof while the film is at rest for the particular frame being projected.

For this purpose, there is provided a connection to the usual house A. C. circuit, or afwet or dry storage battery, by wires 84 and 85 leading to a coil 86 of one or a number of transformers to step up the voltage by means of a coil 81 in a circuit 88 leading to one or more bulb rectiiiers 88 having two wires 96 and 9| to deliver the direct current to one or a series of condensers 82 of any desired size and number of plates, the two sides of which are connected, respectively, by wires 88 and 94, to the brushes 68, 10 and 61, 68. As a result, voltages of `2000 to 6000 will accumulate in the condensers or capacitors 92 until this charge is discharged through the particular bulb 8|, while the shutter opening is opposite to the film frame being projected. The electrical energy 'then rushes at a high speed through the gas in the bulb 8 The bulb in this way is capable of at leastv 10,000 of these short duration flashes of from 1/mm to 1/1,ooo,oac of a second, after which any one or more of the bulbs can be readily replaced by removing it from the clips 11 and `18 and inserting a new bulb instead. Also, the bulb wheels 54 and 55 can be moved to interchange their positions so as not to lose time in replacements of the bulbs and so as to give better access thereto for repairs, etc., and while the films are being replaced.

While I have described my invention above in detail it will be understood that many changes may be made therein without departing from the spirit of my invention.

I claim:

l. A light source of high intensity adapted for lighting in cinematography, comprising a plurality of sets of radially arranged high intensity flash bulbs containing a gas adapted to be rendered incandescent, a rotatable mounting for the said sets of bulbs having an axially displaceable axis for said sets as well as a mechanism for advancing said sets of bulbs upon the rotation of the. mounting, and an electrical means for energizing the bulbs of a set selected by said displacement successivelyl without energizing the bulbs of another set upon the rotating of said mounting, having a circuit closing device which closes the circuits of the bulbs in succession.

2. In combination, a light source of -high intensity adapted for lighting in cinematography, comprising a plurality of sets of radially arranged high intensity flash bulbs containing krypton, a rotatable mounting for the said sets of bulbs having an axially displaceable axis for said sets as well as a mechanism for advancing said sets of bulbs upon the rotation of the mounting, an electrical means for energizing the bulbs of a set selected by said displacement successively without energizing the bulbs of another set upon the rotating of the mounting, having a circuit closing device which closes the circuits of tbe bulbs in succession, and a motion picture apparatus having a reciprocating pull down mechanism geared to the mechanism for advancing the bulbs for intermittently Vadvancing the lm to successive light-receiving positions synchronously connected for movement with the iirst mentioned mechanism and with the circuit closing device.

` WILLIAM E. CELESTIN.

REFERENCES crrED The following references are of record in the le of this patent: A

UNITED STATES PATENTS Number Name Date Dussard Mar. '1, 1916 OTHER REFERENCES Scientific American, February 8, 1913, page 138,

article by Dussard on Co1d'Light.

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