| 摘要 |
<p>987,088. Feeding webs. W. F. PAWLOWSKI. May 15, 1962 [June 5, 1961], No. 18655/62. Heading B6B. [Also in Division G3] Means for controlling a load such as the tension in an endless belt or wire or in a reeling or unreeling apparatus comprises a load sensing element 12 which operates a valve 24 to produce a pneumatic pressure in a conduit 38 which pressure acts on a piston 48 to balance the load on the element 12 and is passed through a surge tank 46 to the upper and lower sides respectively of diaphragm assemblies 94, 96 which are subject on their opposite sides to a reference pressure set by a regulator 70 and are connected by pins 72, 74 to ball valves 76, 78 controlling the supply of air under pressure through selector valves 116, 108 to regulator valves 118, 120 which control an air motor (not shown) for introducing stretch or slack into the belt or wire by controlling brakes, clutches, switches &c. The reference pressure loading on the diaphragms and the effect of a spring 88 on the diaphragm 96 are such that one or other of the valves 76, 78 is opened only in the event of the tension deviating by more than a predetermined amount in either direction from a mean value. The selector valves 108, 116 may be set to place the valves 118, 120 under manual control by pilot valves 110, 114. In a modification, the valves 76, 78 are replaced by electric switches.</p> |
