GB1110545A - Web handling system - Google Patents

Abstract

1,110,545. Fluid-pressure-electric servomotor systems. CANADIAN GENERAL ELECTRIC CO. Ltd. July 16, 1965 [July 25, 1964], No. 30374/65. Headings G3P and G3R. [Also in Divisions B6 and F2] Variations in the length of a web loop 6 in a suction column 5 are detected by a light-sensitive arrangement, the output of which is fed to a lead circuit and amplifier which controls the operation of a hydraulic valve 94 Fig. 10 governing the hydraulic pressure applied to a brake 18 on the web-roll 9. Valve: Liquid is pumped from the reservoir via a flow valve 82 to the cylinder of the brake 18, and the pressure is varied by allowing the liquid to bleed off via orifice 101 under the control of valve member 103. High-pressure liquid flows from a tube 91 and through an orifice 93 to impinge on the upper surface of the valve member 103. By deflecting the tube 91 with an electromagnet 109 controlled by the lead circuit and amplifier, the amount of liquid impinging on the upper surface of the valve member 103 can be varied. The equilibrium position of the valve member 103 is therefore varied, thereby varying the bleed off of liquid from the orifice 101. The pump pressure is controlled by an adjustable pressure relief valve 84, having a safety valve 85 placed in parallel therewith. . Suction column: A series of lamps 56, Fig. 6, are positioned alongside an inner glass wall 52, <SP>"</SP> so that light rays 58 passing through that portion of the suction column not occupied by the loop strike a reflecting surface in the column. Some of the reflected rays 59 impinge on a lightsensitive device 60 such as one or more semiconductor cells, which converts the light energy to electrical energy. The electrical signal obtained from the device 60 represents the position of the loop 6 relative to the column, and this signal is fed into the lead circuit and amplifier to control the brake. To compensate for the change of inertia of the web-roll 9 as the diameter thereof decreases, a mask (117, Fig. 12) may be placed in the light gathering box 55 of the column, so that the pattern of light transmitted through the box is altered, so that the signal is modified according to loop length. To compensate for friction between the web loop and the side of the column, the suction column may have a pair of converging side walls (121 and 122) Fig. 13 which converge according to the expression ° = 2 sine<SP>-1</SP> Á, where ° is the angle between the side walls and 4 is the apparent coefficient of friction between the web and the side wall in frictional engagement with the web during withdrawal from the column. To accommodate webs of different width, each end wall of the suction column may be mounted for transverse movement on a "scissors jack" (140) Fig. 15.