| 摘要 |
A control device is provided for use with an apparatus adapted for the disposition of granular material upon a moving sheet of substrate during the manufacture of roofing shingles. The control device comprises a rotatable cam driven by the shingle manufacturing apparatus and having a variable cam surface, a slidable switch adapted to periodically energize an electric clutch to control the disposition of the granular material, said switch having an actuating arm in contact with the cam surface, an electro-pneumatic transducer responsive to the speed of the moving sheet of substrate and adapted to emit an output signal proportional in magnitude to such speed, and a pnuematic cylinder controlled by the output signal of the transducer and having an extendible stem in engagement with the switch to slide said switch along the cam surface in a direction parallel to the axis of rotation of said cam a distance corresponding to the substrate feed speed, and thereby control the position of the switch actuating arm with respect to the variable cam surface to change the duration of the actuation of the switch, so that disposition of the granular material corresponds with the substrate speed.
|
