Patent GB-1054391-A (GB)
IPC: B41L11/00
Abstract: 1,054,391. Coating apparatus. BLOCK & ANDERSON Ltd. July 25, 1963 [April 25, 1962], No. 15784/62. Heading B2L. [Also in Divisions B6 and F1] In a spirit duplicating machine, the pad or equivalent means for dampening the copy sheets is supplied with liquid from a reservoir by means of a reciprocating pump 22 operated a number of times during each printing cycle. The pump piston rod 21 is pivoted to one end of a lever 20 fixed to a shaft 16 carrying an arm 19 adapted to be engaged by pins 18 on a disc 17 which is coupled by a one-revolution clutch to a continuously-rotating shaft 12 when the printing cylinder is similarly coupled to the shaft. As each pin 18 engages the lever 19, the left-hand end of lever 20 is moved upwardly, a spring 23 subsequently moving the left-hand end of lever 20 downwardly so as to effect an operative stroke of the pump. The pump stroke can be set to one of three values by operating one of three keys 24-26 carrying pins 29 which are engaged by the right-hand end of lever 20 to limit the downward movement of its lefthand end. Each key when depressed moves a plate 30 a short distance leftwardly to release a catch 31 from a pin 32 on the lever 20, the catch normally preventing an operative stroke of the lever. The keys 24-26 together with a priming key 27 described later are self latching and each when depressed releases any other depressed key. Adjusting supply of damping liquid for short sheets. Sensing of the rear edge of a copy sheet as described in Specification 986381 causes a shaft 46 to be turned anticlockwise, this shaft having fixed thereto an arm 47 connected by a spring 48 to an arm 49 pivoted on the shaft. The upper end of lever 49 can either pass under a stop 44 on the lever 20 to prevent an operative stroke thereof or can abut against the stop 44 if the lever 20 has previously been lowered. For normal-length sheets the second operative stroke of the pump has occurred before the rear end of the sheet is sensed, so that movement of the shaft 46 when such sensing occurs causes the lever 49 to abut against the stop 44 without effecting operation of the pump. If, however, a short copy-sheet is used, its rear edge is sensed and shaft 46 is operated before the second pin 18 engages lever 19. The lever 49 is thus moved into abutment with the stop 44, and when the lever 20 is raised by the engagement of pin 18 with lever 19, the lever 49 moves underneath the stop 44 and prevents the second operative stroke of the pump. More than two pins 18 may be provided and also means for sensing different lengths of copy sheets so as to effect appropriate alterations of the number of pump strokes rendered inoperative. Priming. Actuation of the key 27, which is effected when the printing cylinder and disc 17 are not driven, moves the plate 30 leftward to a greater degree than that effected by keys 24-26, at the same time releasing latch 31. The plate 30 is connected by a link 36 to an arm 37 pivoted on shaft 16 and carrying a pin 38 engaging a slot 39 in a link 40, the pin 38 being urged rightwardly by a spring 45. The link 40 is connected by a link 41 to a lever 15 pivoted on the shaft 16 and carrying a roller 14 bearing on a cam 13 fixed to the continuously-rotating shaft 12. Normally, the parts 15, 41, 40 move idly, but if the key 27 is depressed the link 41 is moved clockwise about its upper pivot 42 and a notch 43 thereon engages the stop 44, so that the lever 20 and the pump 22 are operated to prime the pad.