Film advancing mechanism
AssigneePaul Guilden
InventorMiklos Von Kemenczky
Life of this patent
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Abstract
The sprocket assembly for periodic advancement of film in a film projector is supported axially between rotated members and is corotative with the members upon increase in axial force therebetween. One of the members is axially restrained and the second member supported for minute axial movement. Force giving rise to the corotation of the members and sprocket assembly is applied to the second member by selective movement of a magnetically attractable element into a magnetic field generated continuously during projector use.
Claims16
In combination, in a film projector:
- a. drive means continuously operative during projector use;
- b. first and second members each rotated by said drive means about a common axis at common rotational speed, said first and second members being axially spaced from one another, said first member being supported for axial translation toward said second member;
- c. film advancing sprocket means supported axially between said first and second members and rotated thereby upon said axial translation of said first member;
- d. first means for generating a magnetic field continuously during projector use;
- and
- e. second means influenced by said magnetic field for imparting said axial translation to said first member, said first and second means being relatively movable to provide selective disposition of said second means in said magnetic field.
In combination, in a film projector:
- a. drive means comprising a pulley continuously rotated during projector use and first and second coaxial shafts corotative with said pulley at common rotational speed, said first shaft being supported for axial translation relative to said second shaft;
- b. first and second members respectively axially spacedly supported by said first and second shafts for rotation therewith;
- c. film advancing sprocket means supported axially between said first and second members and rotated thereby upon said axial translation of said first shaft;
- d. first means for generating a magnetic field continuously during projector use;
- and
- e. second means selectively movable into said magnetic field and influenced thereby for imparting said axial translation to said first shaft.
In combination, in a film projector:
- a. drive means continuously operative during projector use;
- b. first and second axially spaced members rotated by said drive means at common rotational speed;
- c. film advancing sprocket means supported axially between such first and second members and rotated thereby upon reduction of such axial spacing between said first and second members;
- and
- d. means for reducing said axial spacing between said first and second members comprising first means for generating a magnetic field continuously during projector use and second means selectively registrable with said first means and influenced by said magnetic field to effect relative axial displacement of said first and second members.
Dependencies are inferred from the claim text.