Patent GB-180869-A (GB)
Title: Improvements in plate printing machines
IPC: B41F3/36
Filed: 1921-04-28
Abstract: 180,869. Sattler, R. April 28, 1921. Intaglio-plate printing; bed-reciprocating apparatus; printing - surfaces; driving printing- machines; throw-out arrangements; blankets.-A machine for printing from engraved plates is constructed with a reciprocating bed on which the plate is mounted, the bed being driven by power mechanism comprising a onerevolution clutch which auomaticallv stops the bed after one complete reciprocation. The plate is inked and wiped by hand. The sheet to be printed is placed by hand against a mark on the plate and is carried through the machine by friction only. The bed is reciprocated by crank and link mechanism and has a gradually accelerating motion to commence with and a quick return. The segmental impression cylinder is driven independently of the bed during this initial motion, and the cylinder and a rack on the bed are then geared together until after the impression is completed, the impression cylinder being locked after a complete rotation and held so while the bed is returned with a quick motion, at the end of which the machine is stopped by the clutch. The plate A is positioned against a plate 91 which is held by screw-operated flanged members 87 having flat portions 89 for receiving the plate before the circular flanges are clamped over the edges. The bed is supported on rollers 6, 7, 8, and a central roller 11 with a recessed middle portion, the roller 11 being adjustable by means of eccentric bearings having a circular slot engaged bv a screw 14. The rollers 6, 7, 8 are mounted in a frame carried by standards fitted with work-tables at each side, and the bed is prevented from vertical movement by guides which overhang bearers on the bed. The bed is fitted with a rack 24 connected loosely to it by screws 25 engaging in slots in the rack, a spring 88 being arranged between the rack and a projection on the bed to allow the rack to yield relatively to the bed so as to adjust itself to inequalities of gear &c. between the rack 24 and the gearing 23<1> of a segmental impression cylinder 23. The screws 25 may fix the rack to the bed after the required adjustment. The sheet to be printed is placed on the plate A with the bed in the position shown in Fig. 6. The driving-gear between a motor 92 and a shaft 34 is then put in operation and a clutch finger 48 is operated to release a clutch-bolt 46, which moves under the action of a spring to engage one of a series of recesses in a disc on the shaft 34, and this shaft is driven until the finger 48 automatically releases the bolt 46 at the end of a complete revolution of shaft 34. The shaft 34 drives the bed with a gradually accelerating motion by means of a crank 69, a slotted arm 71, and an inclined link 65 which in time assumes an approximately horizontal position. This crank-mechanism ensures a quick return of the bed. A sector 61 on shaft 34 rotates through gears 30, 29, 28, the impression cylinder at the commencement until the segmental gear 23 engages the rack 24, which then drives the cylinder through the remainder of a revolution, after which the cylinder remains stationary until the bed has completed its quick return, whereupon the operations are completed and the whole mechanism stopped in the position shown in Fig 6. An arm 32 on the shaft of gear 30 is formed with recessed ends which engage a disc on the shaft 34 and holds the gearing locked while the bed returns. The arm 32 is fitted with teeth which engage the sector 61 to start the rotation of the gearing for driving the impression cylinder at the commencement. The clutch is driven from a motor 92, or by an external motor with a belt passing through an aperture 107 in the base 1 and over a fly-wheel 93. The motor shaft is connected by worm gearing to a shaft 96 on which is spliced a change-speed gear which can drive the clutch by gears 43, 98, or 42, 97. The gearing may be enclosed in a chamber 43 containing oil; a guard 46 encloses the chamber and a guard 105 prevents oil from splashing out of the motor chamber. The shaft 34 is fitted with a brake 109 which assists in securing a gradual starting of the bed. The plate A is heated by a lamp 86 mounted on a post 84 held in position by a screw 83'. The impression roller 21, Fig. 2, is formed with V-shaped recesses to receive clamping-bars 75 which hold the blanket in position, the bars being held to links 76 pivoted to the ends of the cylinders and held in position by plates 77<1> operated bv clamping-screws 77. In a modification the rack on the bed is fixed, and yielding springs are arranged between the gear 23<1> and its driving- member. The change-speed gear is arranged between the driving-motor and the worm-wheel, which drives the shaft 34 directly. A brake acts on the bed to steady its motion at the start.