| 摘要 |
PURPOSE:To ensure appropriate feeding of a film, by disposing a lever displaced following up to variations in the diameter of a payout roll, in proximity to a film roll, and controlling the winding angle and contact pressure, on a shaft, of an elastic slidable member having both end parts fixed, in conjunction with the lever. CONSTITUTION:When a film 2 is paid out from a film roller 1 and the diameter of the film roll 1 is reduced, a lever 19 is turned following up to the outer peripheral surface of the roll 1, and a shaft 18 is rotated in the same direction. This rotation moves a roller 15 through the function of a brake-controlling arm 17. A brake spring 13 is contracted with the result of reductions in length and tensile force, whereas the winding angle of a brake band 11 is reduced, resulting in an exponential decrease in the pressure exerted on a brake drum 10 by the brake band 11. Owing to the synergistic effect of these changes, the braking force is markedly reduced. Thus, even when the diameter of the film roll 1 is greatly varied, the braking force is reduced appropriately following up to the variation, whereby variations in back tension are restrained, and the film 2 is stably fed.
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