Sync contact switch for movie camera
OwnerJohn D. Wernerinventor
Life of this patent
Estimating the term…
Abstract
A switch adapted to cooperate with the pull-down claw of a silent movie camera for transmitting an electrical signal each time a frame of movie film is advanced past the shutter of the camera includes an insulating base adapted to be positioned within the film receiving compartment of a movie camera so as to fit around the film gate, the base having a grounding contact arm engaging the gate so as to be grounded through the camera and a contact finger insulated from the gate and disposed for intermittent engagement with the reciprocating pull-down claw which serves to close the switch each time a frame of film is advanced past the shutter.
Claims8
In combination, a movie camera and a switch adapted to be placed in the movie camera, said camera having a film compartment with a channel therein through which the film is intermittently advanced, an electrically conductive reciprocal pull-down claw protruding into the channel and adapted to cooperate with the film to advance the film through the channel, said switch being adapted to close once per frame of film being advanced through the channel and including an insulated base member, said base member being positioned in the film compartment of the camera in adjacent relationship with said channel, active and grounding contact means on said base member for separately grounding the switch and engaging said pull-down claw of the camera with each reciprocating cycle of said pull-down claw.
In combination, a movie camera and a switch adapted to be placed in the movie camera, said movie camera having a film gate of an electrically conductive material, a reciprocally driven electrically conductive pull-down claw protruding into the gate and adapted to intermittently advance film through said gate, said camera having a film compartment having an electrically conductive wall, said gate being mounted on said wall so as to be grounded through the camera along with the pull-down claw, said switch including a base plate of an insulating material having an opening therethrough corresponding in size and configuration to the outer peripheral size and configuration of the film gate, said base plate being positioned in the film compartment in flat abutment with said conductive wall of the camera and in surrounding relationship with the film gate, an electrically conductive ground arm affixed to the base plate and protruding into said opening so as to engage the film gate, an electrically conductive contact arm affixed to the base plate and protruding into said opening so as to be in alignment with the reciprocating pull-down claw whereby said pull-down claw will make electrical contact with the contact arm in each cycle of reciprocation and thereby close the switch once per frame of film advanced through the gate by the pull-down claw.
Dependencies are inferred from the claim text.