Patent GB-1430934-A (GB)
Title: Labelling devices continuously variable friction drive
IPC: B65C9/42
Filed: 1972-05-12
Abstract: 1430934 Labelling machines NORPRINT Ltd 10 May 1973 [12 May 1972] 22317/72 Heading B8F Label-applying apparatus comprises a conveyer (not shown) for moving a row of upright cans through a labelling station 14, means (not shown) for driving a label-carrier web 18 around the sharp edge of a member 20 to detach successive self-adhesive labels from the web, a nozzle 30 for directing a jet of compressed air from a solenoid-operated valve 34 on to the labels as they are detached the web to force them directly on to the passing cans without any label-holding step, and a control circuit Fig. 4 (not shown), for synchronizing the operation of the web drive and nozzle in response to a signal from a photo-electric cell 42 detecting the passing of a can. The cell 42, on reception of light reflected from the end surface of a passing can from a lamp 40, which is inclined and axially offset with respect to the can row, delivers a pulse through a switch SB to a delay circuit board DA including a delay circuit VDAA and, flip-flop circuit R.S.A. After a preset delay, controlled by a potentiometer R100 and commensurate with the size of label and can and intended location of the label on the can, the board DA sends a signal to an inhibit circuit C, which in turn activates the control circuit A of the solenoid valve to energize the valve winding 124, the length of time of the air blast delivered by the valve being controlled by a variable delay circuit VDA and flip-flop circuit RSA. The inhibit circuit includes an inverter, which changes the mode of operation of the circuit from one dependent on a triggering action responsive to a label-leading edge detection to one dependent on label-trailing edge detection, and a flip-flop circuit RSC, which prevents a stray signal actuating the control circuit. The signal from the inhibitor circuit to circuit A is also delivered to a web-drive control board EW to cause a flip-flop circuit RSEW to energize one or other of drive circuits CDEW1 or CDEW2, which in turn energize the coil 126 of an electromagnetic clutch in the web-drive to index the label web until a photo-cell 152 detects the next label gap and generates a signal which triggers the flip-flop circuit to another mode of operation in which the one or other of the drive circuits energizes the coil 128 of an electromagnetic brake in the web drive. At the same time, if the labels are not pre-printed, a printing drum is actuated through a print control circuit board EP, which similarly incorporates a flip-flop circuit RSEP for controlling the modes of operation of driver circuits CDEP1 and CDEP2 to either actuate the electromagnetic clutch or brake in the drum drive, a photo-cell 156 being provided to detect completion of the labelprinting operation and effect the change of mode. Immediately a can is labelled, a signal from the board EP or EW sends a signal to the inhibit circuit triggering it to a condition in which it will respond to a fresh signal from the delay circuit board DA. The nozzle, valve, member 20, light 40 and cell 42 are carried on arm 32 adjustably-mounted by bolt 66 in a slotted fitting 60, Fig. 3 (not shown).