Patent GB-190325684-A (GB)
Title: Improvements in Printing Plate Holders
Inventor: ROCKSTROH CHARLES FREDERICK
Filed: 1903-11-24
Granted: 1904-02-11
Abstract: 25,684. Rockstroh, C. F. Nov. 24. Printing surfaces.-Relates to a holder and fittings for holding electrotype, stereotype, or other printing-plates in a printing-machine. The holder consists of a rectangular plate A, Fig. 25, with slots parallel to the sides, shaped as shown in Figs. 10 and 14, and preferably spaced about 4 picas from centre to centre, and 1 pica wide. It may be built up from rectangular sections held together by dowel pins, and be of any size. On this holder the plates are laid, as in Fig. 25, and clamped between clamps, stops, spacers, &c. A form of clamp is shown in Fig. 17. The whole clamp is dropped into a slot, the head D<1> lying along a transverse slot. It consists of a clamping- piece C', which may have a swivelling head C, the inclined edge of which holds down one part of the plate edge. A screw D passes through the piece C<2>, and also through a tumbler E which moves to one side, and catches in the slot to prevent the clamp from rising. The upper surface has grooves E<3> in it and a hole E<6> serves to receive a pointed tool for lifting the clamp out. The thrust is taken by a head D' bearing on a washer F, which also has an extension F<1> to fit the slot, and form a bearing D'. The head D<1> has teeth into which a short rack fastened to a handle may gear, and by which the clamp may be quickly tightened. The swivel joint allows the clamps to hold the plate in any inclined position, and for finely adjusting the position a small key may be used, with a heel to catch in the teeth of the head D<1>, and so formed with a short toe, that the heel is tripped up when the screw has been sufficiently tightened, and the clamp is not damaged or overstrained. The screw D may be extended and have a left-handed thread on the extended part, fitted with a second clamping-piece, and tumbler, to clamp the other edge of the plate. Also several screws may be used with one long head. A folder point N may either be mounted on a clamp as shown, or fixed on a separate adjustable support. It is used to perforate the sheets and to guide a bookbinder in folding them. Opposite sides of a plate need not always be held between clamps, but may be partly held by end margin bars, side margin bars, or adjustable or solid spacer bars. A side elevation of an end margin bar is shown in Fig. 14, where the plate B presses against the bar I, having a transverse keel l<1>, toothed on the underside, and gearing with a similar keel J, having stops J<2> which fit into a slot parallel to the end margin bar. The position of the rack teeth may be so arranged that an adjustment of half the rack pitch can be given to the bar I by alternately reversing it. The side margin bar H, Fig. 10, has a groove in which the plate edge is held, and a longitudinal fin, which catches in the slot and holds the bar and plate down. A transverse fin lying in a transverse slot prevents the bar from having any longitudinal movement. An adjustable spacer 0', Figs. 25 and 31, may consist of a wedge-piece sliding between two jaws. The jaws have downward projections engaging with the slots and preventing them from falling out, and also have a spring clamping-device to hold them together, and keep the wedge in place. The wedge has a stop to prevent it from being moved too far in either direction, and a small hole, into which an instrument may be inserted to move it along, and alter the width of the spacer. A solid spacer O consists of a plain metal bar of suitable dimensions with one or more downward projections of similar shape to those used on the adjustable spacer. All the before-mentioned parts may be suitably curved to fit on a cylinder, the clamp having the washer F curved on the face butting against the slot side, the tumbler E having its upper surface curved as shown, and the part C<2> having its bottom surface curved. In order to support the printing-plate at any particular point where the printing is likely to be very heavy, a cruciform support, of the same height as the depth of the slots, may be dropped into two slots at their point of intersection and support the plate there. A detachable and adjustable slitter, Fig. 33, may be used to mark the lines along which papers should be folded. The blade Q<8> is fitted in a base Q<7> slotted at each end, and clamped by screws to clamping-pieces Q<1>, Q', and tumblers Q<3>, Q<4>, similar to those used in the clamps.