US1641727A

US1641727A - Motion-picture machine

Info

Publication number: US1641727A
Application number: US40998A
Authority: US
Inventors: James R Bradford
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-07-02
Filing date: 1925-07-02
Publication date: 1927-09-06
Anticipated expiration: 1944-09-06

Description

6 1927. I Sept J. R. BRADFORD MOTION PIETURE MACHINE Filed July 2, 1925 INVENTOR Jame- RE/wafar B @f m ATTORNEY 'motion pictures and more Patented Sept. 6, 1927.

PATENT'OFFICE.

JAMES R. BRADFoRiJ, or SAN-FRANCISCO, CALIFOR IA.

iao'rromrmronn MACHINE.

Application filed my 2,

This invention relates to improvements in particularly to projecting machines therefor.

Among the objects of the invention are to provide means for automatically projecting the ima es. of a motion picture film,-and to automatically repeat the operation indefinitely without human aid, except to stop and start the machine, which is another object which mayalso be accomplished automatically by the interposition of. time clock electric switches, now in common use in other arts. Another object is to eliminate all independent movement between the film and the intermittent film feeding mechanism.

A further object is to provide against frictional film wear and the possibility of breaking the film in the operationof the machine. A further object is to provide means for projecting only a predetermined area of film, as desired. Y

, Other objects andadvantages willappear as this description progresses.

An outstanding weakness in the motion picture projecting art is the breaking of the film by the intermittent feed mechanism. This fundamental fault in the existing types of projecting machines, renders them unfit for automatic operation, since breakage of the film, its repair and rewinding require the'presence and supervision of a skilled op erator continuously, during the operation of the machine.

.All of the" above disadvantages and many others are eliminated by this invention, in whichthe film is wound spirally around a transparent carrier or drum and fixed'there- .to. Theintermittent feed is applied to the drum independent of the film. Old film, the feed'margins of, which have been worn useless or partially destroyed, can be successfully used by this invention.

In this specification and the annexed because it may be. embodied in other forms and it is also to be understood that in and by the claims following the description it is 1925. Serial No. 40,998.

intermittent feed and automatic reverse mechanism, viewed from the same end as Figure 3. i

In detailthe construction illustrated in the drawings comprises the base 1,preferably of cast iron, from which the pedestals 2 and 3 rise,'to support the opposite ends of the shaft 4, fixed-therein by the set .screws 5. One half of this shaft is plain and smooth as at 6 and the other half is provided with the screw thread 7, see Figure 1.

The'film drum comprises the

annular ends

8 and 9, having spokes leading from the hubs 10 and 11, and supporting the cylindrical periphery 12, composed of celluloid, glass or other suitable transparent material, fixed to The hub 10 is plain and has a sliding fit with the surface 6 oflthe shaft, andthe. hub

11 is threaded to engage the threaded portion 7 ofthe shaft. Thus mounted, the 7 drum is capable of longitudinal movement back and forth on the shaft under control of the screw thread, when the drum is rotated v on the shaft. The pitch of the thread 7 is drum should beaccomplished with precision and freedom from lost motion and vibration. f Y

To secure accuracy in the placement of the film on the drum the leadend 13 is cemented to or inserted through a slit in the periphery 12 near the end 8, then wound spirally thereon, ed e to'edge, its full length and the finish en is also. cemented or- 'clamped to the drum, wherever it may terminate; The drum surface is provided with anbccasional upstanding fin. i. 14, partly severed from the body of the celluloid bent up to engage 00 lensf All mounting andmovement of the the registering marginal slot 15, in the edge.

of the standard film. (See Figure 1.) Thus attached, the film becomes a fixed part of the drum and does not come into physical contact with any other part of the machine,

nor depend upon its own tensile strength in the performance of the intermittent feed pictures arranged thereon seriatim, eachto.

be advanced, stopped and again advanced by the intermittent feed, to create the illu- 'sion of motion, when exposed upon a screen by the progecting mechanism, hereinafter described. bviously the emulsion could be applied directly to the periphery 12 and the pictures photographically exposed or printed thereon.

The intermittent feed comprises a ratchet gear 16, freely rotatable on the shaft 4, in alinement with the ratchet-pawl 17, pivoted on the eccentric 18,fixed on the shaft 19,

journaled in the bearings 20 and '21 in the standards 22 and 23, rising from the base 1. This shaft is driven by the pinion 24, fixed thereon and enmeshed with the gear 25, fixed on the shaft 26, journaled in the bearings'27 and 28. This shaft is driven by the Worm gear 29 fixed thereon and enmeshed with the worm 3Q,fixed on the end of the motor shaft 31 of the motor 32, mounted upon the base 1. The ratchet gear 16 is provided with" the same number of teeth that there are pictures in one revolution of the film drum, in this instance one "hundred and twenty-six teeth, equal tothe one hundred and twenty-six exposures in one revolution of the said drum. If a different type of film were used, having more or less exposures, it would be necessar to provide a consistent number of teeth in tlie gear 16.

The gear ratio between the motor shaft 31 and the pawl shaft 17 is calculated to give about eight movements of the pawl per second, in machines using the reduced film for short focus exposure as illustrated or sixteen exposures per second in machines using standard film. I i

Rotary movement is transmitted to the film drum from the ratchet 16, through the rods 33, fixed in the spokes 34 of the ratchet and slidably engaging the spokes 35 of the drum end 9. The opposite ends of these rods are fixed in the arms 35 extending radially from a hub rotatable on the shaft portion 6, for the purpose of-stabilizing the action of the rods 33 in their movement around the shaft 4, to keep them from cramping in the drum end 9, in transmitting the necessary torque to rotate the drumintermittently. One rod is probably sufiicient in "small machines for advertising purposes, but in the larger types for standard projection two or more may be advisable, since it is important that there be no lag or lost motion in transmitting the intermittent motion to the drum, especially in high speed exposure work, such as slow motion pictures that may run up to two hundred or more exposures per second.

The lamp housing 36 is adjustably fixed upon the bracket 37, that is fixed upon the shaft 4 and extends transversely to a point in proximity to. the inside surface of the I periphery 12. The electric cord 38 for supplying current from the generator to the lighting means, in the lamp housing, is carried through the hollow center of the portion 6 of the shaft, th'ence outward through a hole bored into the shaft to meet said central bore; The frame 39 isadjustably fixed upon the end of the bracket 37 and is intended to frame the light projected 17 which advances a new picture area'into' the exposure frame.

This shutter is mounted on the shaft 43, extending outwardly from the bracket 44, rising from the base 1. The shutter is driven through a miter gearing 45 one gear of which is fixed upon the shutter shaft 43, and the other on the end of the drive shaft 46, which is mounted in the bearing 45 on the bracket 44 rising from the base 1. The driven end of this shaft is provided with a gear 47, enmeshed with a similar gear 47, that is fixed upon the pawl shaft 19, Whereby the drum drive and the shutter drive are driven in unison from a common source, to insure precise timing in their synchronous actions. The shutter may be of any of the accepted types, but the rotary type shown, with a segmental opening therethrough, representing about one fifth of its travel past the lens, is preferred, to cause the*light and dark periods necessary to expose and move the film, in the conventional manner.

In starting the machine the drum. is rotated on the shaft 4, until its end 9 is in proximity to the ratchet 16, which brings the first exposure on the lead end 13 of the film'into axial alignment with .the image projecting lens tube 41. The motor switch 48 is now turned on, which starts the motor i 32, and lights the, lamp which is, wired in multiple in the motor circuit. The intermittent rotation of the drum exposes the film for projection, contra clockwise, bringing the film down from above as the drum is rotated. The left hand screw 7 engaging the end 9 of the drum causes it to advance to the left, see Figure 1, until all the film has been exposed through the projecting lens. The drum is returned to the starting position by reversing the drive.

The drive is reversed by means of the slide rod 48, that is slidable in the

guides

49 and 50 rising from the base 1, see Figure 4. The marginal trips 51 and 52 are adjustably fixed upon this slide rod by set screws and are adapted to abut the

ends

8 and 9 of the film drum. By means of these trips 51 and 52 the drum may be stopped, started and reversed at'any point in its travel; whereby any selected part of the film subject may be chosen for projection and repetition, by limiting the lateral travel of the drum to the area predetermined by the trips 51 and 52.

The end of the slide rod48 hasthe yoke 53 fixed thereon which engages the grooved hub 54 of the sliding gear 55, enmeshed with the driven pinion 24 at all times. This gear 55 rotates and is slidable on the stud shaft 56, fixed in the standard 57, rising from the base 1, and slidably meshes and unineshes with the crown gear 58, fixed to the side of the ratchet 16, to which it imparts a reverse movement for retracting the film drum on thethread 7. The reverse movement is clockwise or to the right, while the movement of the, drum for projection is contrawise. At the same time t-hat the sliding [Ill gear 55 is slid into or out of mesh with the ratchet wheel gear 58, the pin 59 fixed on i the rod 48, engages the cam 60, on the pawl to lift it out of engagement during the reverse movement, but permits it to reengage the ratchet 16, for the normal 1ntermit tent feed. The introduction of the sliding gear 55, makes it possible to interpose a gear ratio between the. motor 32 and the gear 58, that will reverse the film drum very quickly.

Since it is desirable that the drum be re versed during the period of darkness. the circuit for the lamp in the housing 36 is wired through the contact switch 61, that is arranged on the standard 57, in such a position'that itsprings open and opens the lamp circuit, when the rod 48 slides forward to accomplish the reverse above described. When the slidingrod is retracted it compresses the contacts of the switch 61 and closes the lamp circuit.

' The present embodiment of the invention illustrated is especially adapted to the projection of advertising films, ranging in capacity' from small machines for projecting pictures on prepared portions of automobile wind-shields or show windows up'to larger units for bill-board and out door work; but it is equally adaptable to use for theater projection, with modifications obvious to those skilled in the art. For instance, drums of suflicient capacity could be made to carry thousands of feet of film and such drums or the cylindrical peripheries 12 could be changed on the machine, in preference to the present time wasting and film destroying method of rcwinding after each run.

' The details of the projecting lens, shut- It is advisable to equip the projecting mechanism with a safety shutter that will automatically drop into the path of the projecting ray of light, should the motor accidentally stop. Such centrifugally operated devices are now regularly supplied with projecting machines to prevent burning the film in the event that the film stops.

The designation motion picture machine as used herein, is intended to define a. complete apparetus' or machine for taking or projecting motion pictures; certain portions or combinative elements of which have been modified by this invention to accomplish new, novel and improved results'by a new mode of operation. as defined in the claim, which are simplified by the inclusion of sub-combinations under this inclusive designation. I Y i The term film is used in the broad sense to mean a series of pictures ofprogressive motion, still life, headings, captions and projectable matter. which may be upon a strip or ribbon film or individually framed on the drum or printed" thereon. The present embodiment of the invention is designed .to utilize the conventional'forms of films now on the market, for economic reasons, without the intention of limiting the invention 1. A motion picture machine comprising a base having. shaft supports thereon; a shaft fixed in said supports and having a screw thread on a portion'of its length; a film drum having one end threaded on said shaft spur gear; areversing slide rod guided on said base and engagingwsaid slideable gear and having trips thereon in the path of the film drum; an electric light projecting means within said drum and an image projecting lens in juxtaposition to said light means.

2. A motion picturemachine comprising a base having shaft supports thereon; a shaft fixed in said supports and having a screw thread on a portion of its length; a film drum having one end threaded on said shaft and the other end slidable thereon; an image film on said drum; a ratchet revolvable on said shaft; rods fixed in said ratchet and slidably engaging said drum; a pawl engagingsaid ratchet; pinion means for operating said pawl; a spur gear fixed to sald ratchet; a sliding gear adapted to engage and disengage between said pawl pin- .ion and spur gear; a reversing slide rod guided on said base and engaging said slideable gear and having trips thereon in the path of the film drum; a cam on said pawl engaging a pin on said reversing rod, whereby said pawl disengages during the reyersal of the drum; an electric light projecting means within said drum and an image projecting lens in juxtaposition to said light means.

3. A motion picture machine comprising a base having shaft supports, thereon; a shaft fixed in said supports and having a screw thread on a portion of its length; a film drum having one end threaded on said shaft and the other end slideable thereon; an image film on said drum; a ratchet revolvable on said shaft; rods fixed in said ratchet and-slideably engaging said drum; a pawl engaging said ratchet; pinion. means for operating said pawl; a spur gear fixed to said ratchet; a sliding gear adapted to engage and disengage between said pawl pinion and spur gear; a reversing slide rod guided on said base and engaging said slideablegear and having trips thereon in the path of the film drum; an electric light projecting means within said drum "and an lmage projecting lens in juxtaposition to said light means; a switch in circuit with said electric light means, operated; by said reversing rod, whereby the light is extinguished during the reversal of the drum.

an image film on' said drum; a ratchet revolvable on said shaft; rods fixed in said ratchet and slideably engaging said drum;

a pawl engaging said ratchet; pinion means for operating sald pawl; a spur gear fixed to said ratchet; a sliding gear adapted to engage and disengage between said pawl pinion and spur gear; a reversing slide rod guided on said base and engaging said slldeable gear and having trips thereon in the path of the film drum; an electric projecting means within said drum; an image projecting lens in juxtaposition to said light means; a cam on said pawl engaging a pin; on sa d reversing rod; a switch in circuit with said electric light means, operated said re-'- versing rod, whereby the light is extinguished and the pawl disengaged during the reversal of the drum.

5. A motion picture machine comprising a base having shaft supports thereon; a shaft fixed in said supports and having a screw thread on a portion of its length; a film drum having one end threaded on said shaft and the other end slideable thereon; an image film on said driim; a ratchet r evolvable on said shaft; rods fixed in said ratchet and slideably engaging said drum; a pawl engaging said ratchet; pinionmeans for operating said pawl; a'spuri gear fixed to said ratchet; a sliding gear adapted to engage and disengage between said pawl pinion and spur gear; a reversing slide rod glbalided on said base and engaging said sl1dea e path of the film drum; an electric light projecting means within said drum and an image projecting lens in juxtaposition to said light means; a shutter interposed in the beam of light from said light means and synchronously operated with said pawl by said pawl pinionf 6. ,A motion picture machine comprising a base having shaft supports thereon; a'

shaft fixed in said supports and having a gear-and having trips thereon in the screw thread on a portion of its length; a

film drum having one end'threaded on said shaft and the other end slideable thereon;

an image film on said drum; a ratchet revolvable on said shaft; rods fixed in said ratchet and slideably engaging said drum; a pawl engaging said ratchet; pinion means for operating said pawl; aspur gear fixed -to.'said ratchet; a sliding gear adapted to means within said drum; an image projectreversal of the drum; a shutter interposed ing lens in juxtaposition to said light means; in the beam of light from. said light means a cam on said pawl engaging a pin on said and synchronously operatedwith said pawl 10 reversing rod; a switch in circuit with said "by sa1d pawl pinion.

electric light means, operated by said re- In testimony whereof I have hereunto afversing rod, whereby the light is extinfixed my signature. I guished andv the pawl disengaged during the JAMES R. BRADFORD.