| 摘要 |
<p>1,073,269. Feeding webs. M. D. MARTIN. Nov. 12, 1965 [July 21, 1965], No. 48019/65. Heading B6B. [Also in Division F2] In a self-propelled, web roll transporting stand having a pair of hydraulically operated lifting arms with hydraulically braked chucks, an automatic brake control is provided in which the hydraulic brake pressure is controlled in accordance with decrease in weight of the web roll due to a decrease in diameter thereof. With the web roll 12 clamped in the chucks, hydraulic jacks 6 are supplied with highpressure fluid via a manual valve 11 to raise the pair of arms 1. When the arms 1 are raised to the working position, a detector 14 opens a bleed valve 13 in the hydraulic lifting circuit, whereupon the manual valve is operated to close the circuit. A hydraulic sensor 24 is incorporated in the lifting circuit, the piston 25 of which is pivoted at 27 to a balanced arm 20. As the weight of the web roll 12 decreases, so will the hydraulic pressure in the jacks 6, resorting in movement of the balanced arm 20. The hydraulic brake circuit includes two brake cylinders 19, a pressure regulator 31 having its piston 29 pivoted to the balanced arm 20, and a master cylinder 46 which is manually adjustable to preset the braking torque. Movement of the balanced arm 20 controls the braking torque via the pressure regulator 31. The balanced arm 20 is initially balanced in a predetermined attitude by an adjustable spring 39. The weight of the average web roll is substantially proportional to the square of the diameter of the web roll. To compensate for the change of this square function as the web roll diameter decreases, the balanced spring 39 exerts its pull through toggle links 36 and 37.</p> |
