Patent GB-706682-A (GB)
Title: Improvements in and relating to apparatus for inverting sheet material
IPC: B65G47/248
Filed: 1949-07-29
Abstract: 706,682. Endless belt conveyers. MACLELLAN, W. H., CLARK, E. C., LOWRIE, M. [Representative of LOWRIE, W. J. D.], and IMPERIAL CHEMICAL INDUSTRIES, Ltd. July 28, 1950 [July 29, 1949], No. 19975/49. Class 78 (1) [Also in Groups XVI and XL (b)] An inverter for sheet material comprises a cradle having its longitudinal axis in the line of travel of the sheets and having therein at least one pair of driven conveyers for the reception of the sheets, the conveyers of each pair being arranged one above the other, the cradle being connected to two end frames each having a diametral slot to permit the passage of sheets, a pinion or toothed member being adapted to permit passage of sheets and secured to a trunnion, and a toothed member adapted to rotate the pinion or toothed member through 180 degrees, the toothed member being driven by means controlled through an electric circuit by means controlled by the moving sheets. As shown, a frame 100 is mounted on trunnions 105 rotatably mounted on rollers 107, the trunnions carrying a rack wheel 108 co-operating with a rack 109 movable in a reciprocating slide 110. The frame 100 carries two belt conveyers 101 and 101<SP>1</SP> running on spring-loaded rubber-covered idler rollers 102 and 102<SP>1</SP> driven by a motor 103. Boards 55 are fed past a photo-electric cell 200, such that a light beam from alight source 202 is no longer interrupted by a rockable shutter 201 when the trailing edge has passed a finger controlling the shutter. The anode of the cell is connected directly to the grid 6, Fig. 1, and through a resistance R to the cathode 7 of a thermionic valve 4. The anode of the valve is connected to a relay 11, comprising a coil 10a and condenser 10b, controlling a switch 12 controlling a circuit containing a coil-operated switch 14, a delay break relay 40 having a switch 16 controlled by a coil 15, and a coil 17 controlling a double pole switch 18. When the light beam is interrupted by the shutter the bias from the grid of the valve is removed such that the valve anode current closes, through the relay 11, switch 12, thus energizing a coil 13 and opening switch 14 to deenergize coil 15, thus allowing switch 16 to reclose. When, after the passage of a board, the shutter uncovers the cell the bias is reimposed on the valve grid and the anode current falls to zero, thus de-energizing relay 11 and opening switch 12, which in turn de-energizos coil 15, closes switch 14 and energizes coil 17 through the switch 16. Coil 17 closes the switch 18, thus energizing a solenoid 20 until switch 16, after a short delay, is opened. While the solenoid 20 is thus energized it pulls the trigger of a clutch operating mechanism so as to cause the clutch to drive a countershaft 114 driving the rack 109. While boards are passing into the frame 100 between the conveyers 101 and 101<SP>1</SP> the motor 103 is driven until the frame is rotated by reason of the trailing edge of a board passing the photoelectric cell, the frame being rotated after a short delay by the rack 109, the delay being such as to allow the end of the board to reach the frame. On completion of 180 degrees rotation, contact poles on the cradle engage fixed contacts, such that the motor 103 is restarted to feed in the next board and feed out the inverted board through a slot 106. In a modification, the photo-electric cell may be replaced by switches mechanically operated' by the moving boards.