Patent GB-674842-A (GB)
Title: Improvements in or relating to sheet separating and forwarding machines
IPC: B65H3/08
Filed: 1948-04-22
Abstract: 674,842. Feeding sheets. BACKHOUSE, H. T. April 22, 1949 [April 22, 1948; Feb. 11, 1949; Feb. 11, 1949], Nos. 11073/48, 3774/49 and 3866/49. Class 100 (i): A sheet-feeding apparatus is constructed with suction separators 18, Fig. 1, or 111, Fig. 8, which act upon the rear edge of a pile and are attached to pistons raised by suction when the cylinders in which they work are sealed by engagement of the pile by the separators, and the pistons are held in raised position by spring- controlled catches 32 or 118 as the separators move with the sheets which are finally released from the separators by the opening of vent valves 41 or 119 by engagement with fixed stops. Stops 33 release the catches to allow the separators to move downwardly and engage the top sheet. In the first form, Fig. 1, a pair of separating units each comprising two separators 18 carried by a piston 15 are supported by brackets 5 carried by a bar 6 mounted on a hollow square support 4. The cylinders 10 are mounted so as to oscillate with a hollow shaft 11 connected to a source of vacuum, and the separators 18 are controlled by a parallel-link system, so as to maintain a constant angle of inclination, comprising a lever arm. 21 attached to a hollow arm which supports the grippers 18, a link 27 guided by guides 23 on the cylinder and formed with a slotted end which is engaged by a pin 24 secured to the bracket 5 at the same level as the shaft 11 and at a distance therefrom equal to the length of the arm 21. The separation of the sheets is assisted by a presser foot 62 which is guided for vertical movements by a tube 60 connected to a source of compressed air and fitted with a flap valve 83, Fig. 6, which directs the air either to a bore 86 in the foot or to a nozzle 81 on a tube 80 attached to the foot for directing air to the sides of the pile to fluff the edges. The foot 62 rests on the pile as' the grippers 18 descend on to the pile, and when they rise with a separated sheet, the cylinder 10 is given a slight rearward movement which raises a crosshead 53 by means of an arm 50 on the cylinder having a roller 51 engaging a slot 52 in the crosshead. This movement of the crosshead causes a bell-crank lever 70, 73, to actuate a latch lever 91 which normally holds the valve 83 against the action of a spring tending to move the valve to direct the air to the foot. A blast of air is thus delivered to the foot as the grippers carry a sheet forward as the cylinder reverses its movement. This movement causes the crosshead 53 to be lowered and the latch 71 engages a catch-piece 72 on the foot 62 so as to be ready to raise the foot. Also just before the limit of the downward movement of the crosshead is reached the bell-crank 95 engages an adjustable stop 74 and by means of lever 98 actuates the arm 88 of the shaft 84 of the flap valve 83, and the air is directed to the fluffing nozzles. The crosshead is guided by a rod 54 which together with a rod 55 serve as pile-registering devices. In a modification, Fig. 8, the suction separators 111 are pivotally mounted on hollow plungers adapted to be drawn into pivoted cylinders 110 when the suckers are sealed by engaging the pile. Two sets of separators are mounted in frames 104 carried by tubes 100, and a control cam shaft 102 is mounted in the frames. Each cylinder 110 is oscillated by a cam 106 which engages a roller 115 attached thereto, and the inclination of the separators 111 is controlled by a cam track 123 engaging a roller 122 on an arm 120 on each separator. Each cylinder is fitted.with a spring catch 118 for holding the plunger in raised position, and with an automatically operated vent valve 119 for releasing the suction action. The valve for controlling the supply of air to the presser-foot 152 and to the fluffing apertures 151 is controlled by a lever 160 which is oscillated about a horizontal pivot by a lever 161 operated by a lever arm 180 and roller 182 engaging a cam 107 on the shaft 102. The lever 160 engages a'notch 155 in a short-radial arm which controls a flap valve, and a spring 156 retains the flap valve in either of its set positions. The air tube 144 provided with foot 152 is mounted in a slide 130 which is adjustable along'guides by screw mechanism, and is held in adjusted position by a screw and nut. The air-tube 144 and its presser foot is raised and lowered under the control of cam 108 which oscillates a lever 170 provided with a projection which engages under an abutment on the air tube. The adjustment of the slide 130 does not interfere with the action of the levers which control the operation of the valve, and the vertical motion of the presser foot 152. In both modifications the co-operating pistons and cylinders which control the separators may be replaced by equivalent bellows or diaphragms and chambers. The apparatus in both cases is mounted so as to be adjustable for dealing with sheets of different sizes and thicknesses. Specifications 674,843 and 674,844 are referred to.