The invention provides a cable drive device (10) including a linear drive member (12), and a cable drum (14) attached to a support bracket (30, 32) adapted to be affixed to a surface. The cable drum (14) has an axle (26) supported by the support bracket (30, 32) to allow rotation of the cable drum (14). The cable drum (14) has a cable (42) affixed at either end of said linear drive member (12) and tautly wrapped around the cable drum (14). The cable drum (14) is located between the ends of the linear drive member (12) to, in use, allow the linear drive member (12) to be guided through the bracket (30, 32) to move the linear drive member (12) longitudinally when the axle (26) is rotated.

The invention provides a cable drive device (10) including a linear drive member (12), and a cable drum (14) attached to a support bracket (30, 32) adapted to be affixed to a surface. The cable drum (14) has an axle (26) supported by the support bracket (30, 32) to allow rotation of the cable drum (14). The cable drum (14) has a cable (42) affixed at either end of said linear drive member (12) and tautly wrapped around the cable drum (14). The cable drum (14) is located between the ends of the linear drive member (12) to, in use, allow the linear drive member (12) to be guided through the bracket (30, 32) to move the linear drive member (12) longitudinally when the axle (26) is rotated.

An opening/closing device according to the present invention includes a gate, a fall prevention unit, a support release unit, a first float, a floating prevention unit, a second float, and a floating prevention release unit. The gate receives a flow of fluid, and is able to fall down toward a downstream direction of the flow. The fall prevention unit supports the gate, thereby preventing the gate from falling down. The support release unit releases the support for the gate by the fall prevention unit. The first float is arranged on an upstream side of the gate, is arranged on one of the left side and the right side of the gate viewed from upstream, and is less in the specific gravity than the fluid. The floating prevention unit prevents the first float from floating.