| 摘要 |
The invention relates to a direct acting pneumatic control system for controlling a dual diaphragm, or double acting cylinder type automatic guiding system. The control device and system is used to selectively adjust the position of one end of a roll relative to the opposite end, in order to adjust the position of an endless web traveling over a series of rolls. In order to adjust and control the guide roll position, it is necessary to alternately exhaust one diaphragm, and or cylinder end, while maintaining the flow of air to the opposite diaphragm or cylinder end. This in effect shifts the roll in a lateral position, effectively steering the web in the proper direction to effect the necessary web correction. To activate and control the valve position, the control valve is equipped with a palm which follows the web and continually monitors the web position and activates the control valve spool to modulate the "flow-exhaust" rates to bring the web to a corrected position with no over-run or "hunting" for position. The palm and its associated rod must follow the web when the web is moving away from the palm.
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