| 摘要 |
680,966. Sound-film sneed-controlling devices. WESTERN ELECTRIC CO., Inc. Dec. 5, 1950 [Dec. 6, 1949], No. 29735/50. Class 40 (ii). A sound film driving mechanism in which the film is passed over a rotable drum 3 at the sound translation point comprises a pair of rollers 5, 8 mounted on arms 6, 9 pivoted at 7 and 10. The arms are interconnected by a spring 11 and in order to adjust the pressure exerted by each roller on the film to keep the tension in the film constant, the spring is attached to adjusting screws 12, 13. The arm 6 is connected to a dash pot 15. In order to check whether the arms are parallel to each other, a member 18 having a line 19 is fixed to the arm 9, and a member 20 having an aperture 21 is fixed to the arm 6. The line and aperture are so positioned that when the line is in the centre of the aperture the arms are parallel. The arms should also be horizontal. Specification 622,535, [Group XX], is referred to. |
