Patent GB-1303981-A (GB)
IPC: B65H1/22
Filed: 1968-05-03
Abstract: 1303981 Feeding sheets J E THOMPSON 28 July 1969 [3 May 1968] 21158/68 Heading B8R Apparatus for feeding sheets to a machine from a pile 33, Fig. 1, has adjustable side lays for positioning the pile, an inwardly-directed lip 8 on a front stop 7 engaging the front of the pile, and a feeder head 11, mounted above the pile, having two sucker mechanisms mounted thereon, each suction mechanism engaging the rear end of the uppermost sheet and first moving the sheet rearwardly so as to release its front edge from the lip 8 and then moving the sheet forwardly towards the machine, the arrangement being such that one sucker mechanism is moving forward with a sheet whilst the other sucker mechanism is returning from its forward position to engage the next uppermost sheet. The head 11 may be fixed above an automatically raised pile but, as shown, is adjustable along arms 12 fixed to members 19 pivoted at 20 and connected to counterbalancing springs 23 connected to a screw-adjusted block 24. Wheels 13 on the head 11 rest on a main pile 6 of fanned-out sheets placed by the operator on a loading platform 2. A belt 3 is driven to move the pile 6 forward against the front stops 7, which may be spring-urged downwardly, to form a sub-pile 33 from which the sheets are fed, the belt 3 being stationary during sheet separating. The two sucker mechanisms are identical, and each comprises suckers 41, Fig. 4, attached to a hollow suction tube 40 carried by an approximately triangular plate 43. The plate 43 has a ball race 45 running in an arcuate groove 47 in a guide block 46, and also has a pin 49 projecting outwardly through a slot 48 in the block 46. An upward extension 58 of the block 46 has a ball race 59 running in a horizontal slot 61 of another guide block 62 mounted for vertical movement along a guide rod 65. A shaft 68 in the head 11, which shaft is driven by bevel gearing from a shaft 27, Fig. 1, carries cams 70, 71, which respectively cause horizontal movement of the block 46 and vertical movement of the block 62. A third cam 72 operates a lever 79 engaging the pin 49 to tilt the suckers 41. Another cam 81 operates a valve 84 controlling the suction to the suckers, a further cam 82 operates a valve 85 controlling the air supply to an air jet 102, Fig. 5, assisting sheet separation and an air blast pile agitator 103 comprising an open ended box with a flexible reed as described in Specification 1,303,983 or a reciprocated perforated tube directing streams of air towards the pile. A final cam 83 operates a device 91, Fig. 5, for jogging the sub-pile 33 against the front stop 7. In operation, when one sucker mechanism has descended to engage the rear end of the uppermost sheet of the sub-pile 33, the other sucker mechanism has just released a previous sheet to feed rollers 32 or to suction forwarding nozzles. The first sucker mechanism is then tilted by the lever 79 and pin 49 to bend up the rear edge of the sheet, air being blown through the sheets by the agitator 103. As soon as the suckers have rocked back, the agitator 103 is shut off and the jogger 91 is operated to align the sub-pile. The air jet 102 is now actuated to separate the top sheet from the pile 33 and the suckers are moved upwardly to raise the rear end of the sheet. Next, the front stop 7 is raised by a cam 9, Fig. 1, and the suckers are moved rearwardly to free the front edge of the sheet. The suckers are now moved forwardly, and the air jet 102 cut off, the agitator 103 however being rendered operative to form a cushion of air to support the sheet and in readiness for the separation of the next sheet by the other sucker mechanism. Replenishing the pile.-The guide block 62, Fig. 4, may have an arm 115 carrying a screw 116 operating a micro-switch 117 controlling a motor circuit driving the belt 3 to effect replenishment of the sub-pile 33 as described in Specification 21159/68. The height of the subpile 33 may however be detected by a spring- urged front stop 7 also as described in Specification 1,303,982. Detecting faulty feed.-For detecting separation of more than one sheet, a top sheet when moved rearwardly passes between two rollers 107, 108, Fig. 4, carried by fixed and pivoted arms 1@@, 105 respectively connected in a low voltage electrical circuit 110. An extension 111 on the pivoted arm 105 can engage a microswitch 112 in another circuit. If no sheet is fed, circuit 110 remains intact and signals to impart the information that no sheet is present, to the machine operating on the sheets. When a single sheet is fed, the circuit 110 is broken and the apparatus continues to run normally. If two sheets are separated, the arm 105 is moved sufficiently for the switch 112 to be actuated, the associated circuit causing a suction roller in front of the rollers 32, Fig. 1, to be operative to engage the upper one of the two sheets and feed it to a reject hopper. Should more than two sheets be separated, the greater movement of the arm 105 operates the micro-switch 112 to cause stoppage of the apparatus.