Patent GB-729207-A (GB)
Title: Improvements in or relating to apparatus for folding continuously fed sheets of different lengths
IPC: B65H45/101
Filed: 1951-10-10
Abstract: 729,207. Folding sheets. GADSBY, W. March 5, 1953 [Oct. 10, 1951], No. 23542/51. Class 42 (2). Apparatus for fractional transverse folding of continuously-fed sheets of different lengths has fold-timing means comprising an endless conveyer band moving synchronously with sheet feeding means and carrying two series of cups, detectors for the leading and trailing edges of a sheet which cause a ball to be placed in a cup of one series on actuation by the leading edge and another ball to be placed in a cup of the other series when actuated by the trailing edge, and two interconnected series of switches actuable respectively by the balls and so arranged as to cause the folding mechanisms to operate at the appropriate location on the sheet. As shown, Fig. 1, a sheet delivered by an ironer 1 is given a first central fold between rollers 7, 8 by means of a folding knife 6 and a second central fold between rollers 10, 11 by means of a second knife 9. Prior to the two folding operations, the front half of the sheet is received in partition boxes 29, 30 respectively. The twice-folded sheet is delivered on to a tray 31 or on to a transverse conveyer. A delivery band 32 can be moved by a screw device 33 to a position where it will receive a sheet from the delivery lip 4 of the ironer and deliver it to tray 31, thus by-passing the folder. Knives 6, 9 are oscillated to effect folding by pneumatic devices 16, 17 controlled by a timer C, Fig. 3. The timer includes an endless chain conveyer 18 driven in synchronism with the drums 2 of the ironer and comprising carriers 20 presenting on their outer surface two side-by-side rows of cups, one row passing beneath a series of switches 24 and the other row beneath a second series 24A displaced laterally and longitudinally from series 24 as shown in Fig. 5. The switches a, b, c, &c. of one series are connected to the correspondingly lettered switches of the other series, the pairs of switches being in circuit with a solenoid 25 controlling the air supply to pneumatic device 16. In operation, when the leading edge of a sheet lifts a feeler 26 located in the ironer 1, a steel ball 21 is released by a dispenser 23, Fig. 3, into a conveyer cup of one row so as to be carried below switches 24 and close the switches in succession; when the trailing edge of the sheet releases feeler 26, a second ball 21 is released into a cup of the other row so as to pass below switches 24A. When the two balls simultaneously close corresponding switches (say f, f or g, g) of the two series, the circuit through solenoid 25 is completed and folding knife 6 is actuated. By so relating the speed of conveyer 18 to that of the ironer drums 2 that a ball will travel from dispenser 23 to a point midway between the two series of switches while the leading edge of a sheet travels from feeler 26 to the path of knife 6, sheets will automatically be folded at their mid-point irrespective of their length. Knife 9 is actuated similarly by feeler 26A and conveyer 19 to make the second fold at the centre of the oncefolded sheet. While the spacing of switches in bank 24 is the same as in bank 24A for the first fold, for the second fold the spacing in bank 24 is three times that in bank 24A. Conveyers 18, 19 are inclined upwardly so that balls can be returned to dispensers 23 via gravity shoots 22. The machine may be adapted for multilane operation: .The folding mechanism may be operated electrically or hydraulically instead of pneumatically. Instead of feelers 26, 26A, photo-cell devices or air valves may be used; these may be located at the sheet entry region of the ironing machine.