Title:
【発明の名称】フィルム減速ユニット
Document Type and Number:
Japanese Patent JP3169380
Kind Code:
B2
Abstract:
A projector having a rolling loop film transport mechanism is provided with a film decelerating cam unit that is located in advance of the aperture of the projector. Deceleration pins carried by a pair of vertically spaced arms that project from the cam unit engage in upper and lower marginal perforations in the film and travel with the film towards the aperture and decelerate the film as each frame is advanced. The cam unit includes two cams, one of which causes the decelerating motion of the pins, and a return motion in the reverse direction, while the other cam causes the pins to advance and retract into and from the film path respectively. By positively retracting the pins, their return movement against the direction of film travel can take place independent of the motion of the film. As compared with the prior art, acceleration forces and resultant stresses on the cam are reduced and the cam unit can operate at higher frame rates and/or with smaller rotor gaps.
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Inventors:
Shaw, William, Sea.
Maxwell, Ian
Smith, Irvine, W.
Maxwell, Ian
Smith, Irvine, W.
Application Number:
JP51381691A
Publication Date:
May 21, 2001
Filing Date:
August 12, 1991
Export Citation:
Assignee:
Imax corporation
International Classes:
G03B1/42; G03B1/18; G03B1/22; G03B1/48; G03B21/00; G03B21/46; (IPC1-7): G03B21/46; G03B1/42
Other References:
【文献】米国特許3600073(US,A)
Attorney, Agent or Firm:
Takashi Koshiba