A ribbon feed device includes; a drive gear capable of rotating about a first shaft in clockwise and counter-clockwise directions by a rotation force transmitted from a drive source; a ribbon feed gear for feeding an ink ribbon capable of rotating about a second shaft; and an intermediate gear which swings about the first shaft while meshing with the drive gear, meshes with the ribbon feed gear at a first position during the rotation of the drive gear in the clockwise direction, meshes with the ribbon feed gear at a second position during the rotation of the drive gear in the counter-clockwise direction, and renders the ribbon feed gear rotate always in the same direction irrespective of the rotation direction of the drive gear.

A drive mechanism for transmitting bidirectional drive to two or more rotary actuator spindles, having a disc driven by an input shaft. Each spindle carries a spur gear which engages alternately with inner and outer tooth sections formed at different positions around a respective track in the disc. To accommodate several gears, tracks are provided at two different radii and three tracks of different width are nested together. The spur gears and tooth sections can be replaced by cams and tracks or shaped levers and pegs. The disc can be moulded and enables standard valves to be used in a complex operational sequence.

The problem of providing a simplified actuator apparatus (10) for converting unidirectional motion to multidirectional motion is provided by a driven member (14) rotatable about a first axis (18) and a drive member (12) rotatable about a second axis (28) generally parallel to and spaced from the first axis (18). The driven member (14) has first (20) and second (22) radially disposed, diametrically opposed cam followers. The drive member (12) has first (36) and second (38) radially disposed cam actuators. The first cam follower (20) of the driven member (14) is engageable by the first cam actuator (36) of the drive member (12) for driving the driven member in one direction of rotation in response to rotation of the drive member in one direction. The second cam follower (22) of the driven member (14) is engageable by the second cam actuator (38) of the drive member (12) for driving the driven member in an opposite direction of rotation in response to continued rotation of the drive member in the same, one direction.