US2639513A

US2639513A - Means for optically aligning motion-picture projectors

Info

Publication number: US2639513A
Application number: US145441A
Authority: US
Inventors: Sr Willard C Ricord
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-02-21
Filing date: 1950-02-21
Publication date: 1953-05-26
Anticipated expiration: 1970-05-26

Description

y 1953 w. c. RICORD, SR 2,639,513

MEANS FOR OPTICALLY ALIGNING MOTION-PICTURE PROJECTORS r Filed Feb. 21, 1950 INVTOR. is 44 36 MAM/P0 Cfi/co/m Se Patented May 26, 1953 UNITED STATES PATENT OFFICIE MEANS FOR OPTICALLY ALIGNING MOTION-PICTURE PROJECTORS 6 Claims. 1

This invention appertains to a novel and practical means for effecting the accurate alignment of the light projecting components on the optical axis of a motion picture projector having its light source comprised in a fixed carbon electrode and a relatively adjustable carbon electrode disposed in axial alignment with the light projecting components and with each other, in order that maximum lumens of light,

generated by the light source, will impinge the picture viewing screen.

For the attainment of this and other objects of equal importance, the invention resides in the certain new and useful combination, construction, and arrangement of parts, as will be hereinafter more fully described, set forth in the appended claims, and illustrated in the accompanying drawings, wherein:

Figure 1 is a schematical view of the light projecting components of a motion picture projector and showing the cooperative association of parts to accomplish the objects and purposes of the invention;

Figure 2 is a front side elevation of a circular member, constituting a mounting for one end of the sighting element extending axially between the centers of the reflector and the lens housing, the same to be removably mounted in the center of the reflector, upon the removal of the fixed carbon electrode therefrom;

Figure 3 is a sectional view, taken through the line 33 on Figure 2, looking in the direction of the arrows;

Figure 4 is a perspective view of a shuttle to be mounted in the adjustable carbon electrode holder of the projector, upon the removal of the adjustable carbon electrode therefrom, for the passage of the sighting element through the axial bore thereof;

Figure 5 is a top plan view of a bracket to secure the adjustable carbon electrode holder, and consequently the shuttle, rigidly in a set position during the aligning operation;

Figure 6 is a side elevation of a gauge plate to be cooperatively associated with the film aperture of the projector;

Figure '7 is a sectional view, taken through the line 'l-'! on Figure 6, looking inthe direction of the arrows;

Figure 8 is a face view of an aperture element to be frictionally fitted within the inner end of the lens housing of the projector;

Figure 9 is a sectional view, taken through the line 9-9 on Figure 8, looking in the direction of the arrows;

Figure 10 is a front face view of a circular mounting for the other end of said sighting element, the same to be frictionally fitted within the front end of the lens housing of the projector;

Figure 11 is a sectional view, taken through the line I l| l on Figure 10, looking in the direction of the arrows; and,

Figure 12 is a rear side elevation of the sight element mounting as otherwise illustrated in Figures 2 and 3.

Referring to the drawings, and more particularly to Figure 1, the light projecting components of a standard motion picture projector, as illustrated therein, are comprised in a reflector A, a carbon electrode holder B, a film aperture element 0, and a lens carrier or housing D; it being understood that one of two carbon electrodes (not shown) ordinarily extends horizontally through a central opening in the reflector A and the other likewise through the holder B, the latter being carried at the upper end of a vertically disposed arm b and has a screw clamp c to secure the carbon electrode in place. The lower end of the arm b has a screw threaded opening engaged by a complementally screw threaded shaft d for the adjustment of the electrode, carried by the holder, relatively to the said one electrode which is supported in a fixed position in the central opening in the reflector. For the purposes of the present invention, both electrodes are dispensed with until after the aligning operation is completed, which operation is efficiently performed by means of a visual sight line, preferably a light flexible wire l0, extended axially from the center opening in the reflector A to the lens carrier or housing D and through certain cooperative instrumentalities presently to be described.

In Figures 1, 2, 3, and 12, a mounting for the rear end of the sight line or wire I9 is shown, and it is comprised in a circular member I4, of a diameter slightly greater than that of the center opening in the reflector, which has its rear side reduced, as at l6, for fitted engagement with said center opening. Formed in spaced relation about an axial opening 18 in the member [4 are several bores 21), in each of which is mounted a spindle 22 having a latch element 24 on its rear end and an actuating knob 26 on its front end; a coiled spring 28 being housed within the bore and encircled about the spindle between the inner end of the knob and an annular shoulder at the inner end of the bore. With the seating of the member M in the reflector opening, the

knobs 26 are turned to swing the latch elements- 24 to positions behind the edge of the opening where they are firmly held in contact with the rear side of the reflector by the tensioning effect of the springs 28 on the inner ends of the knobs 26. A circular recess 30 is formed in the rear face of the member l4, concentrically with respect to the axial opening therein, to house a universal structure, or gimbal, which, as best shown in Figures 3 and 12, is comprised in an outer annular element or ring 32 within which is trunnioned, as at 36, a second annular element or ring 34. Trunnioned, as at 40, horizontally of and Within the second element or ring 34 is a cylindrical element 38, which has a bore 42 extending diametrically through the same medially between its ends and a V-shaped throat 44 opening into the bore for the insertion into the latter of the rear end portion of the sight line or wire l0, which end portion terminates in an enlargement 46, preferably spherical in form, to bear against the inner side of the element 38 to prevent accidental disengagement of the end, when the sight line or wire it! is threaded forwardly through the opening it for the securement of its forward end in centered relation within .the lens carrier or housing D, as will presently be explained.

Now referring to Figures 1, 10 and 11, a mounting for the other, or forward, end of the sight line or wire I is shown, and it is comprised in a circular body 48 which is to be frictienally engaged within the front end of the lens carrier or housing D. The front side of the body i8 is formed with an annular depression surrounding a central. cylindrical portion 53 which has here 52 opening axially through the same to house the jaws of'a clutch or collet 54, the inner end of ti. bore being reduced and opening through the rear side of the body for the threading ofthe forward end of the sight line or wire I!) inwardly thereof and. into engagement with the said jaws. Also frictionally engaged within the rear end of the lens carrier or housing D is a circular plate 56 which has a central aperture 58 opening through the same in line with the bores in the aforesaid cylindrical element 38 and the body 43. With the mountings l4 and 48 installed as stated, the sightline or wire In is stretched taut between the same and the forward end thereof is clamped between the jaws of the clutch or collet 54.

Upon the removal of the electrode from the holder B, and as shown in Figures 1 and 5, it is replaced by an elongated member fidhaving the form of a shuttle, which is provided with an axi a1 bore 62 and a V-shaped throat 64 coextensive therewith and opening into the same to facilitate its placement on the sight line or wire l0 and, when so placed, it may be slid along the latter and into position within the holder B; in which position, it will be secured against displacement by the screw clamp 12, which, in turn, is prevented from being accidently loosened by means of a clamp type bracket mounted on the arm 17, the latter being indicated at B.

In addition to the foregoing aligning instrumentalities, a gauge member 88 is provided to cooperate with the sight line or wire [0 and is associated with the film aperture element C to such end. This gauge is shown in Figures 1, 6 and '7, and is comprised in a flat, relatively thin plate, rectangular in form, and provided with a supporting head ill at its top end and an aperture 72, of a. somewhat greater diameter than that of the sight line or wire Iii, opening through its exact center and communicated by a V-shaped throat '14 opening laterally outward through a side edge of the plate. A rectangular frame 16 is provided on one side of the member 68 in centered relation with respect to the aperture 12 and is disposed within the film aperture C when placed in position relative thereto with the sight line or wire it] passing through the aperture 12; the throat 74 allowing for the entry of the sight line or wire into the latter during the placement of the member.

Now, with the described members or devices installed as stated, the perfect alignment of the components of the projector will be indicated when it is ascertained that the sight line or wire i6 is exactly centered in the bore 62 of the shuttle 60 and the apertures 58 and E2, of the

plates

56 and 68, respectively. If, however, such perfection of alignment is not so indicated, the oifending component of the projector is to be mechanically adjusted and affixed until the desired accurate alignment is attained.

It is to be here noted that by the employment of the universal, or gimbal, with the member I, the reflector A be readily adjusted about itsv axis without in any way affecting the alignment of the sight line or wire l0. Also, a purpose of'the shuttle 68, other than that heretofore stated. for the same, is to disclose the accuracy of alignment of the carbon holding components when the holder B is moved toward, or away from, the reflector A by a turning motion imparted to the worm shaft d; a hand crank e being provided at one end of the shaft for its manipulation.

Having thus fully described a preferred embodiment of my invention, it is to be understood that the words which I have used are words of description rather than of limitation, and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention in its broader aspects.

What I claim is:

1. Means for effecting perfect optical alignment. of the light projecting components such as the lens component and film aperture component of a motion picture projector having as its light source a fixed carbon electrode and a relatively movable carbon electrode, the fixed electrode being normally supported axially in an opening in the center of the light reflector and the movable electrode in an adjustable liolderand in line with the fixed electrode, said means comprising a flexible sighting strand element stretched axially from the center of the onening in the reflector to the center of the carrier forthe lens components, said element passing through the electrode opening in the holder from which the electrode has been removed and from thence through the film aperture component, a mounting for one end of said element removably secured in the said'opening in the reflector from which the fixed electrode has been removed, said mounting including a universal self centering unit with which the said one end of said element is coupled, and a gripping means for the other end of said element removably centered in the lens carrier from which the lens components have been removed, the accuracy of alignment of said components being indicated when the element is observed to pass through the exact centers of the reflector and holder openings and the film aper-' ture.

2. The invention as defined in claim 1, with an elongated member in the form of a shuttle having a longitudinal bore of a slightly greater diameter than that of said sighting element and a substantially V-shaped throat coextensive with said bore and opening laterally outward therefrom for the passage of said element therethrcugh and into said bore, said shuttle being slid along said element after its engagement therewith and centered within said adjustable.

holder and secured in place by the clamping medium normally employed to secure the movable electrode therein.

3. The invention as defined in claim 1, with a gauge plate adapted to be positioned alongside the film aperture component and having an aperture in its center of a lesser area than that of the aperture in the film aperture component and a slightly greater diameter than that of said element and a substantially V-shaped throat opening laterally outward from said aperture through a side edge thereof to facilitate the positioning of the sighting element in the aperture, and means carried by said plate to engage in the aperture of said film aperture component to retain the plate in position with its aperture disposed in the exact center of the latter aperture.

4. The invention as defined in claim 1, with the mounting for the said one end of the sighting element having an axial bore and an overall diameter slightly greater than that of the opening in the reflector, the rear side of said mounting being reduced to have fitted engagement in said opening, latching means carried by said mounting and adapted to be engaged with the rear side of the reflector about said opening, and means carried by said mounting crosswise of the rear end of said bore for the attachment of said sighting element thereto.

5. The invention as defined in claim 1, with the mounting for the said one end of the sighting element having an axial bore and a recess formed in its rear side concentrically with respect to said bore, a gimbal housed within said recess, and a horizontal member mounted within the inner element of said gimbal for the attachment of the sighting element end thereto, said gimbal allowing for the adjustment of the reflector about its axis without affecting said sighting element. 6. The invention as defined in claim 1, with the mounting for the said one end of the sighting element having an axial bore, a horizontal member carried by said mounting in rear and crosswise of said bore and having an opening through the same in line with the latter, said sighting element having the form of a length of a light flexible wire and having its rear end passing through said bore and said opening, an enlargement on the rear end of said sighting element, said second mounting for the said other end of said sight line element having an axial bore for the passage of the said end therethrough, and a collet mounted on the outer side of said second mounting in line with the axial bore therein to secure the said end after said sighting element has been stretched taut to cause said enlargement to bear against said horizontal member.

WILLARD C. RICORD, SR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 17,665 Guillet May 13, 1930 FOREIGN PATENTS Number Country Date 838,806 France Dec. 16, 1938 OTHER REFERENCES Journal, Soc. Mot. Picture Eng, vol. 21 (August 1933), pages 94-96,