Improvements in or relating to web unwinding mechanism

877,210. Automatic level control systems. ELECTRIC & MUSICAL INDUSTRIES Ltd. Feb. 27, 1958 [March 9, 1957], No. 7862/57. Class 38 (4). [Also in Groups XVI, XXXVII and XXXVIII] In a web unwinding mechanism (see Group XVI) a switch 18 is provided in each compartment 11 to control the operation of motors driving the capstans 8a and 9a by opening when a maximum quantity of tape is present in one of these compartments, these motors then being supplied at reduced power through a resistance. Opening of one of these switches also causes, through operation of a relay, a further switch to close to supply the motor driving the corresponding spool to be supplied with reduced power. Further switches 19, provided in compartments 10 of the bins 6 and 7 are closed by lateral pressure of the tape when a compartment contains a predetermined maximum quantity, thus energizing the motor driving the appropriate spool to wind tape thereon from that compartment. Switches 22, provided adjacent the bottom of each compartment 11, are opened when the corresponding compartment is nearly empty to bring the motors driving the spools under the control of switches 19. The direction of tape feed past the transducer 2 may be reversed by operation of a switch, not shown, coupled to mechanism which controls the supply of suction to the suction rollers 4 and 5. Specification 877,209 is referred to.