| 摘要 |
PURPOSE:To accurately match the traveling speeds of the front curtain and the rear curtain and increase the speed of the shutter by comparing the traveling speed signal of the front curtain and a reference signal when the shutter operates thereby controlling the brake. CONSTITUTION:A magnetic recording belt 2 and a magnetic head 3 are used as a traveling speed detecting means for a front curtain 1 and a frictional brake 4 is used as a traveling speed controlling means. Such recording by which a constant frequency signal is produced in the head 3 when the front curtain 1 travels at the design value is being made in the belt 2. The output signal of the head 3 when the shutter operates is compared with the reference signal of a crystal oscillator 7 in a comparator 6, the compared output whereof is applied to the brake 4, whereby the traveling speed of the front curtain 1 is controlled. The traveling of the rear curtain is controlled in the same manner as for the front curtain. |
