| 摘要 |
<p>A suction-air control device for a rotatable sheet-transfer drum having suction-type grippers disposed thereon and having a journal with a rotationally symmetrical surface, includes a rotary valve disposed on the journal of the sheet-transfer drum for connecting the suction-type grippers to a stationary suction-air source. A stationary housing is provided for the rotary valve. A device controls a supply of suction air from the suction-air source to the suction-type grippers with a time lead or a time lag as a function of the rotational speed of the sheet-transfer drum. At least one suction-air bore extends from the interior of the journal to the surface thereof. One suction-air bore is connectable to the suction-type grippers. The rotationally symmetrical surface of the journal forms a sealing surface of the rotary valve. At least one closing member formed with at least one air-passage opening disposed over a defined rotational-angle range connects the one suction-air bore formed in the journal with at least one connection hole formed in the housing of the rotary valve.</p> |
