Patent GB-266773-A (GB)
Title: Improvements in and relating to sheet-feeding mechanism and duplicating and other machines comprising the same
IPC: B41L39/08
Filed: 1925-10-08
Abstract: 266,773. Clatworthy, J., and Gestetner, Ltd., D. Oct. 8, 1925, Tripping-arrangements. -In a duplicating or like machine of the kind in which the rotary impression or like cylinder is prevented from coacting with the printing or like member if a sheet is not fed correctly, the impression cylinder is controlled by improved feeler mechanism comprising a feeler which is released during the operation of the sheet separating and forwarding mechanism, and according to the positions assumed by the feeler if a sheet is present or not the printing or like members are brought into printing position or remain in inoperative position. As applied to a stencil duplicator fitted with a feed mechanism of the kind described in Specifications 252,749, [Class 100 (i), Feeding and delivering webs &c.], an impression roller 60, Fig. 1, is mounted at each end in a carriage 59 which is intermittently raised and lowered by oscillating arms 65 fitted with collars 62, through which pass pins 61 on the carriages, springs 63 being interposed between the carriages and the collars. The carriages are each provided with a pin 58, and as they are raised into printing position, the pins 58 register with recesses 55 in lever members 51 pivoted at 52 to the machine frame, or come into contact with shoulders 53 on the lever members. The roller 60 thus moves to operative position, or is prevented from doing so. The levers 59 are controlled by the feeler mechanism, which is operated by the sheet-feeding mechanism, comprising reciprocating feeders 4 operated from a shaft 30, and co-operating with an oscillating bar 28, which clamps the top sheet when pressed against a plate 26, Fig. 4, and causes the sheet to be buckled by the feeders 4. Subsequently the bar 28 rotates through half a revolution to the position shown in Fig. 1, and the sheet is fed over the bar 28, and in this position a feeler bar 31 with fingers 32 corresponding with gaps or recesses in the bar 28 is moved towards the bar 28 by means of lever arms 33 oscillated by lever- and-pin connection with an oscillating member 37, which is operated in one direction by a cam on the shaft 30, and returned by spring action. If a sheet is present over the bar 28, the member 37 is moved to such a position that a pawl 47 on a link 49 connected to the lever 51 engages a notch 46 in the member 37, and the lever 51 is thus moved to cause the recess 55 to engage a pin 58, and the roller 60 moves to printing position. If, however, a sheet is missing the pawl 47 engages a notch 45, as shown in Fig. 4, and the shoulder 53 then prevents the roller 60 from rising to printing position. The pawl 47 is released at each operation of the machine by a pin 79 on a carriage 59 acting on a trip lever 72, which acts on the pawl 47 to move it from the notch 45, or 46. The link 49, lever 51, and pawl 47 are controlled by a fixed spring 75, and the link and lever have a pin and slot connection permitting of relative motion. In order to inkup the machine when a fresh stencil is inserted, the feeler device may be put out of operation, and the control mechanism set so that the roller 60 contacts regularly with the backing sheet of the stencil. The mechanism for effecting this comprises a slotted link 82, Fig. 5, having connection with a pin 80 on a lever arm 33 of the feeler mechanism. This link 82 is mounted on an eccentrically mounted pin 83 on a shaft 84 controlled by a weighted arm 86. As shown in Fig. 5, the link 82 is set so that the feeler arm 33 can oscillate freely. When however the shaft 84 is rotated half a revolution, the arm 33 is held permanently in raised position, and the lever 51 is moved by a link 88 to cause the recess 55 to remain permanently opposite to the pin 58 and so permit the roller 60 to rise regularly.