Phase adjusting apparatus for sheet-fed printing press

A phase adjusting apparatus for a sheet-fed printing press for adjusting a relative phase in a rotational direction between a paper sheet feeder and a printing apparatus which are coupled through a chain, comprising:

• a frame;
• a sprocket which is in contact with said chain from the inside toward a tension side of said chain;
• a slide member, mounted on said frame through rails, for supporting said sprocket through a short shaft such that said slide member is movable along the longitudinal direction corresponding to a direction perpendicular to an extension direction of the tension side of said chain;
• slide member driving means for moving said slide member in the longitudinal direction wherein said slide member comprises a thin-walled portion at an upper portion thereof, a slide block having stepped screw holes, spring pins fitted in said stepped screw holes, and adjusting screws threadably engaged with said stepped holes and engaging with upper ends of said spring pins, said spring pins being surrounded by said spring members;
• and
• a tension sprocket supported on said slide member through a short shaft and in contact with said chain from the inside toward a slack side of said chain, said tension sprocket being biased by a spring member so that the chain is tensioned.