Sprocket-type mechanism for moving photographic film

Claim 1

A SYSTEM FOR MOVING WITH A SUBSTANTIALLY CONSTANT LINEAR VELOCITY A WEB HAVING SPACED PERFORATIONS ADJACENT AT LEAST ONE LONGITUDINAL EDGE THEREOF, THE PERFORATIONS HAVING A PITCH SUBSTANTIALLY EQUAL TO OR LESS THAN A PREDETERMINED PITCH, COMPRISING IN COMBINATION: A ROTATABLE MEMBER ABOUT WHICH THE WEB IS ADAPTED TO BE AT LEAST PARTIALLY WRAPPED IN FRICTIONAL ENGAGEMENT THERWITH, SAID MEMBER HAVING A PERIPHERAL SURFACE AND A PLURALITY OF CIRCUMFERENTIALLY-SPACED TEETH EXTENDING FROM SAID SURFACE FOR ENTERING THE PERFORATIONS IN THE WEB, SAID TEETH HAVING A PITCH CORRESPONDING SUBSTANTIALLY TO THE PREDETERMINED PITCH; MEANS FOR ROTATING SAID MEMBER AT A SUBSTANTIALLY CONSTANT VELOCITY; FIRST MEANS POSITIONED ADJACENT SAID ROTATABLE MEMBER FOR GUIDING THE WEB INTO ENGAGEMENT WITH SAID MEMBER; AND SECOND MEANS POSITIONED ADJACENT SAID ROTATABLE MEMBER GENERALLY OPPOSITE SAID FIRST MEANS FOR GUIDING THE WEB INTO AN OUTGOING PATH; SAID SECOND MEANS COOPERATING WITH SAID FIRST MEANS TO URGE A PORTION OF THE WEB INTO FRICTIONAL ENGAGEMENT WITH SAID SURFACE AND TO ESTABLISH A PREDETERMINED TENSION IN THE WEB PORTION, WHEREBY MOVEMENT OF THE WEB IS EFFECTED BY SURFACE FRICTION BETWEEN THE WEB AND SAID SURFACE AND BY SUCCESSIVE ONE OF SAID TEETH ENGAGING THE LEADING ENDS OF THEIR RESPECTIVE PERFORATIONS, THE TRANSFER OF MOVEMENT OF THE WEB BY ONE TOOTH TO THE NEXT TOOTH OCCURRING WHEN THE PERFORATION ENGAGED BY SAID ONE TOOTH IS LEAST PARTIALLY IN THE OUTGOING PATH OF THE WEB AND DIFFERENCES IN THE PITCH OF SAID TEETH AND THE PERFORATIONS BEING COMPENSATED FOR BY THE RELATIVE FRICTIONAL SLIPPAGE BETWEEN THE WEB PORTION AND SAID SURFACE.

Claim 2

A SYSTEM FOR MOVING WITH A SUBSTANTIALLY CONSTANT LINEAR VELOCITY A WEB HAVING SPACED PERFORATIONS ADJACENT AT LEAST ONE LONGITUDINAL EDGE THEREOF, THE PERFORATIONS HAVING A PITCH SUBSTANTIALLY EQUAL TO OR LESS THAN A PREDETERMINED PITCH, COMPRISING IN COMBINATION: A ROTATABLE MEMBER ABOUT WHICH THE WEB IS ADAPTED TO BE AT LEAST PARTIALLY WRAPPED IN FRICTIONAL ENGAGEMENT THERWITH, SAID MEMBER HAVING A PERIPHERAL SURFACE AND A PLURALITY OF CIRCUMFERENTIALLY-SPACED TEETH EXTENDING FROM SAID SURFACE FOR ENTERING THE PERFORATIONS IN THE WEB, SAID TEETH HAVING A PITCH CORRESPONDING SUBSTANTIALLY TO THE PREDETERMINED PITCH; MEANS FOR ROTATING SAID MEMBER AT A SUBSTANTIALLY CONSTANT VELOCITY; FIRST MEANS POSITIONED ADJACENT SAID ROTATABLE MEMBER FOR GUIDING THE WEB INTO ENGAGEMENT WITH SAID MEMBER; AND SECOND MEANS POSITIONED ADJACENT SAID ROTATABLE MEMBER GENERALLY OPPOSITE SAID FIRST MEANS FOR GUIDING THE WEB INTO AN OUTGOING PATH; SAID SECOND MEANS COOPERATING WITH SAID FIRST MEANS TO URGE A PORTION OF THE WEB INTO FRICTIONAL ENGAGEMENT WITH SAID SURFACE AND TO ESTABLISH A PREDETERMINED TENSION IN THE WEB PORTION, WHEREBY MOVEMENT OF THE WEB IS EFFECTED BY SURFACE FRICTION BETWEEN THE WEB AND SAID SURFACE AND BY SUCCESSIVE ONE OF SAID TEETH ENGAGING THE LEADING ENDS OF THEIR RESPECTIVE PERFORATIONS, THE TRANSFER OF MOVEMENT OF THE WEB BY ONE TOOTH TO THE NEXT TOOTH OCCURRING WHEN THE PERFORATION ENGAGED BY SAID ONE TOOTH IS LEAST PARTIALLY IN THE OUTGOING PATH OF THE WEB AND DIFFERENCES IN THE PITCH OF SAID TEETH AND THE PERFORATIONS BEING COMPENSATED FOR BY THE RELATIVE FRICTIONAL SLIPPAGE BETWEEN THE WEB PORTION AND SAID SURFACE.