| 摘要 |
<p>An arrangement for metering a blast of air delivered to a driven machine, particularly a sheet separation device of a sheet feeder. A control slide is connected via an air intake opening to a pressure source, and the control slide has an air discharge opening connected to the driven machine and leading into the open. The latter opening is controlled or disconnected during upward movement or stoppage of the machine coupled to the driven machine by means of a control element actuated as a function of the machine speed. The air intake opening and the air discharge opening leading to the driven machine, face each other coaxially, and upon reaching a set final speed, these openings are connectable by means of a coaxial recess passing through the control element. A rotary valve plug with a through-bore is provided to form the control element. The air discharge opening leads to the outside and is located offset relative to the air intake opening in the valve plug direction of rotation corresponding to a speed reduction. The through-bore of the valve plug in this region has an oppositely-directed expansion corresponding to the amount of offset. The valve plug is connected by a crank arm mounted on a bearing trunnion, and this crank arm is connected to a servomotor operating as a function of the machine speed.</p> |
