US 4,537,482 AGranted

Motion picture film movement apparatus

OwnerLewis Weinerinventor

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Abstract

A captive film loop apparatus moves film through a film gate in a manner to increase the dwell time of each film frame in the gate over that normally available with presently known captive film loop apparatus. Film loops on either side of the gate are held captive by first and second rollers which are moved in unison along a given path for a first given period during which the first roller takes up all film fed to it and the second roller releases all film taken from it. The rollers are then moved in unison along a return path to their original positions during a second given period substantially less than the first given period. Film in the film gate is stationary during the first given period and moved through the gate from one frame to the next within the second given period. The construction is such as to provide for a very smooth acceleration and deceleration of the film so that rapid projection of large film formats is possible without damaging the film perforations.

Claims12

Dependent claims

An apparatus for intermittently moving film through a film gate in a manner to provide a dwell time for each film frame, greater than one-half the period of a complete cycle, comprised of the dwell time and the transport time involved in moving the film from one frame to the next, said apparatus including, in combination:

(a) first and second rollers;
(b) means for feeding film to said first roller and taking up film from said second roller including a first sprocket wheel about which film to be fed to said first roller passes, a second sprocket wheel of the same size as said first sprocket wheel about which film taken up from said second roller passes and means for rotating said sprocket wheels at equal constant rates;
(c) first and second arms;
(d) means pivoting said arms at first and second pivot points coinciding respectively with the axes of rotation of said first and second sprocket wheels, extending ends of said arms mounting said rollers so that back and forth swinging movement of said arms moves said rollers along arcs defining a given path and a return path;
(e) a rotatable member having a camming means on its periphery following a direction constituting a function of the rate of movement of the rollers along said given path and return path;
and
(f) a cam follower connected to the ends of said first and second pivot arms opposite the extending ends on the other side of said pivot points movable by said camming means in a repititive pattern in response to rotation of said member, said first and second rollers being rocked back and forth by action of said cam follower in unison along said given path for a first given period during which the first roller takes up all film fed to it and the second roller releases all film taken from it and in unison along a return path to their original positions during a second given period less than said first given period whereby film in said film gate is stationary during said first given period and moved through said gate from one frame to the next within said second given period.

4 more elements

A captive film loop apparatus for intermittently moving film through a film gate in a manner to provide a dwell time for each film frame greater than one-half the period of a complete cycle comprised of a dwell time and transport time involved in moving the film from one frame to the next, said apparatus including, in combination:

(a) a housing structure supporting said film gate;
(b) a first sprocket rotatably mounted to said structure for feeding film at a constant rate for passing into said film gate;
(c) a second sprocket rotatably mounted to said structure for taking up film at a constant rate exiting from said film gate;
(d) a first roller positioned to receive film from said first sprocket before said film passes into said film gate;
(e) a second roller positioned to receive film from said film gate before the film is taken up by said second sprocket;
(f) a rotatable member in said housing and having a camming means on its periphery;
(g) arm means including first and second arms supporting said first roller and said second roller;
(h) means pivoting corresponding intermediate points on said arms to said first and second pivot points coinciding with the axes of rotations of said first and second sprockets, said first and second arms having extending ends mounting said rollers so that back and forth swinging movement of said arms moves said rollers along a given path and a return path;
(i) a cam follower including a link connected to the ends of said arms opposite said extending ends on the opposite sides of said pivot points and responsive to said camming means for moving said arms means to thereby move said rollers in unison along said given path for a first given period during which said first roller takes up all film fed to it by said first sprocket and the second roller releases all film taken from it by said second sprocket and for moving said first and second rollers in unison along said return path to their original positions during a second given period less than said first given period, whereby film in said film gate is stationary during said first given period and moved through said gate from one frame to the next within said second given period.

6 more elements

Dependencies are inferred from the claim text.