GB763169A - Improvements in and relating to laundry folding machines - Google Patents

Abstract

763,169. Folding sheets. BAKER PERKINS, Ltd. May 19, 1953 [July 18, 1952], No. 18187/52. Class 42 (2). [Also in Groups XXXVIII and XL (b)] In a laundry folding machine of the type in which each article is advanced to a folding station where its arrival initiates the displacement of folding means which engage the article, the arrival is detected by a photoelectric cell the illumination of which varies in a number of steps by the article to control the folding. The invention is applied to interposing the necessary delay between the detection of the article and the initiation of the folding means commensurate with the conveyer speed and the spacing between the photo-cell and the folding means. As shown, the leading edge of a sheet to be folded carried on a conventional conveyer X interrupts the first (L<SP>1</SP>) of a pair of light beams L<SP>1</SP>, L<SP>2</SP> incident on a photo-electric cell P. The increase in resistance of the cell controls the current in a pair of solenoids SOL2 and SOL3 in the anode circuit of a valve V. SOL3 is saturated and the reduction in current does not reduce its pull, whereas that of SOL2 falls appreciably. Hence, a spring-loaded switch arm is rotated from position I where it is held by SOL2 to position II where it is held by SOL3. A timing circuit commences to charge closes a holding circuit for a solenoid SOLI and continues charging until the leading edge of the sheet interrupts the record beam L<SP>2</SP> when SOL 3 also de-energizes. Switch S now moves to position III energizing relay D which then starts the timer discharging and opens one branch of a supply circuit of SOLI controlling a sheet gripping arm F. When the charge on timing circuit T has leaked away after a period proportional to the time taken by the leading edge to intercept the two light beams, contact T1 is opened, opening the other branch of the circuit of SOL1 which is de-energized. Arm F is now moved by spring M to grip the leading edge of the sheet. The conveyer continues running, thus forming the fold in the sheet. When the trailing edge of the article is carried clear of the first light beam switch S moves back to position II breaking the circuit of relay D energizing solenoid SOL1 which releases the leading edge of the article so that it falls on the trailing edge. When the trailing edge clears beam l<SP>2</SP>, switch S is restored to position I. Specifications 618,157, 754,109 and 763,170, [Group XXXVIII] are referred to.