| 摘要 |
In order to increase the reliability in selectively disabling a signature feeding apparatus, and to avoid the problems which are inherent in mechanical systems, a unique dual mode pneumatic system is contemplated for use with a cyclically operable signature feeding apparatus. The feeding apparatus will generally include a driven rotary drum having a plurality of signature grippers disposed about the periphery thereof. The signature grippers are adapted to grip signatures seriatim from a signature supply hopper. A suction assembly is driven by a cam for shifting signatures seriatim from the signature supply hopper to the rotary drum for gripping by the signature grippers. The suction assembly includes oscillating suction grippers in communication with a source of vacuum. The signature feeding apparatus further includes a cam follower assembly operatively associated with the suction assembly to control movement of the oscillating suction grippers toward and away from the signature supply hopper. With this arrangement, a dual mode pneumatic system is provided having a cam follower spring mode for normally biasing the cam follower assembly toward the cam to maintain engagement therewith and a cam follower disabling mode for selectively supporting the cam follower assembly in a position out of the full path of movement of the cam to thereby disable the oscillating suction grippers.
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