US 5,517,262 A · Motion picture drive system

Abstract

A changeable sprocket wheel assembly enables the rapid and reliable mounting and demounting of sprocket wheels of different diameters on a film drive shaft by unskilled operators, while assuring that the sprockets are held with high precision. In one arrangement, an inboard sprocket wheel member (50, FIG. 2) receives the inboard portion (55) of a driven shaft in a close sliding fit and is lockable to the shaft, the inboard member having a small diameter land (52) with a ring of sprockets (54) thereon. An outboard sprocket wheel member (60) has the same size land with sprockets thereon, and fits around the outboard shaft portion (65) in a close sliding fit and is detachably fixable to the inboard member to abut it and rotate with it. When a larger diameter sprocket wheel is required, the outboard member (60) is removed and a large sprocket wheel element (70, FIG. 3) is mounted in its place, the large element having two large lands (72, 74) that each have a ring of sprockets (76, 78) thereon, with the large element lying in close sliding fit with the outer shaft portion and being detachably fixable to the inboard member. In another assembly (160, FIG. 10), an inner member (162) receives the drive shaft in a close sliding fit and is rotatably fixed to it, while sprocket wheel members (180, 196) of different sizes each have cylindrical inner surfaces that are closely slidable on the inner member and are mounted to abut it and rotate with it. Detachable fixing of two members is accomplished by a projecting pin portion (100, FIG. 9) that is retained by a spring ring (102).

Claims5

Dependent claims

A changeable sprocket wheel assembly for mounting on a driven shaft of a film transport which moves film that has first and second sides and first and second rows of sprocket holes at said sides, at different film speeds for a given speed of rotation of said shaft, comprising:

an inboard sprocket wheel member that has a hole with an axis, and that is constructed to receive said driven shaft in a close sliding fit, said inboard member being lockable to said shaft to run therewith and not shift axially thereon, said inboard member having a first land extending cylindrically about said axis at a first diameter for supporting said first film side and having a ring of spaced first sprockets for engaging said first row of sprocket holes;
an outboard sprocket wheel member that has a second land extending cylindrically about said axis at said first diameter for supporting said second film side and having a ring of spaced second sprockets for engaging said second row of sprocket holes, said outboard member being fixable to said inboard member so they both turn together about said axis and do not shift axially relative to each other;
and a large sprocket wheel element that has first and second land parts extending cylindrically about said axis at a second diameter which is greater than said first diameter and that has a ring of spaced sprockets at each of said land parts for supporting both sides of said film and engaging the holes thereat, said large sprocket wheel element being fixable to said inboard member when said outboard member is not present, so that said large element and said inboard member turn together about said axis and do not shift axially relative to each other, with one of said land parts of said large element directly surrounding said first land of said inboard member.

Dependencies are inferred from the claim text.

Motion picture drive system

Life of this patent

Motion picture drive system

Life of this patent

Abstract

Claims5