Fig. 12. represents one of the modes of applying the power of the wheel and pinion for driving the rollers : A a pinion fixed to the cheek of the press, which acts in the teeth of the wheel 13, which wheel is fixed to the spindle of the upper roller C. A cross with eight spokes DD, is fixed to the spindle of the pinion A, by which the motion is communicated. This application of the wheel and pinion is certainly a considerable improvement, but it has its dis advantages. The chief of these are, that the pinion cannot be placed at a sufficient distance from the spindle of the upper roller, so as to admit of a wheel of sufficient diame ter for it to act in to give the requisite power. Another disadvantage is the great length and number of the levers, which renders the action too slow for common work. We give the following description and representation, (Fig. 13.) of a neat, useful, and at the same time a very pow erful press, which remedies these defects, and which has been in use for upwalAs of twelve years without requiring any repair. It is wade wholly of cast iron, under the di rection of Mr. Lizars of Edinburgh. Its chief qualities are its durability—the compactness of its form—the mode of applying the power of the pinion to the wheel seen in the engraving, instead of its being placed at the cheek of the press, as shown in Fig. 12.—and its cheapness, con sidering the great size of plate which its dimensions are calculated to take in. From an examination of the repre sentation given in the accompanying plate, it will appear evident that, by the mode of fixing the pinion, and from the great diameter of the wheel into which it acts, greater power is obtained ; and from the pinion being worked by a winch-handle, greater uniformity and despatCh is given when required in common work. There is also a conve nient apparatus for fixing the cloths in cases where the plate is too large to admit of the length of the cloth being. warped round the roller and fixed to it. This apparatus is seen at A, Fig. 13. where the dotted line represents the cloths warped in a triangular form round the roller of the press, and extending to the two small rollers b b, which the cloths make to revolve along with the 'oiler attic press. The diagram, Fig. 14. will convey a more perfect idea of this apparatus, AA, the two small rollers, round which and the upper roller of the press the cloths b b revolve, when the press is set in motion, d d represent two small screws, which are so contrived as to slacken or tighten the cloths when required. In Fig. 13. B represents the plank upon which the copperplate rests; it is also made of cast iron, and supported upon the small narrow rollers c.
This press is calculated to print a plate the size of a sheet of double elephant paper, and costs about 401.
The following description of Mr. Perkins's new presses, and the representations Figs. 15 and 16. are extracted from Newton's Journal of Arts.
" Fig. 15. shows an improved steel or copperplate, or block printing press. The principal improvements con sist in a new method of heating the plate or block ; in the use of a tympan for the purpose of saving the expense of making the plates or blocks any larger than is necessary to receive the engraving, as well as to save ink, and also time and labour in changing the plates or blocks. The manner in which these objects are effected, will appear From Figs. 15 and 16. AA, &c. is the cast-iron frame of the press ; B the upper cast-iron roller, on the axis of which is fixed the wheel C, with handles around it for the workman to pull by ; D the lower cast-iron roller, FT the bed of the press, made partly of cast-iron and partly of wood; the part E is of cast iron, the better to resist the pressure of the rollers, and to convey the heat employed to the warm plate or block ; the plate or block G is fixed upon the bed, by means of screws passing through counter sunk holes made in the bed front the under side of it, and into screwholes made partly through the plate or block it self. The tympan LI is a wooden frame, covered with cop per, and turned into hinges I 1, and having an aperture in it large enough to enclose the plate or block, the sides of which aperture arc made feather-edges, so as to overlap the bevelled edges of the plate or block, and prevent them from soiling the paper. The cast-iron part of the bed of the press, with the plate or block upon it, is heated by means of a block of cast-iron J, which is supported upon the plate Ii, with turned up edges, and which block is re moved and replaced by another from time to time as it cools. In use, the frame of the press is inclined, the front end resting upon the floor, and the other being raised by two screws passing through screwed holes in the sill of the press frame, one of which screws is shown at L. The in
tention of this inclination is to cause the bed to return after the impression is made of its own accord; and in order to admit of this, a portion of the roller B is removed; and three pairs of additional rollers MINIM ate added for the bed to roll upon with more facility, each pair of rollers being fixed upon a separate axis, with necks working in brasses.
The blankets NN are secured to the cast-iron bed at one end, by the blanket holder 0, and the stretcher P is affixed to the end of them, from which cords QQ pass over the pullies RR, and have weights, one of which is shown at S, hung to them. By this means the blankets are kept stretched and relieved from the roller, and prevented from matting or becoming dirty in use. The roller B is kept up when the bed is released by the following contrivance. TT are two wooden blocks, lying at the bottom of the chases in the press frame, at each end of these blocks is fitted a screw nut, into which are screwed two screws, having flat cylindrical heads WW, with notches or teeth cut around them, and which project beyond the sides of the press-frame, so as to be easily turned either way, as required. Upon these heads the brasses XX are rests, in which the necks of the axis of the roller B turn, and the roller can du- reby be supported at the required height, as above mentioned.
Fig. 16. represents a cylindrical steel or copperplate printing press. AA. &c. is the cast-iron frame of the press; B the main cylinder for holding the plait s, which has a solid cast-iron cylindrical surface or rim, upon which the plates are secured by means of screws fastened through holes made in the surface of the cylinder, front the inside of it, and entering into screw boles made partly through the plate The main cylinder is mounted on an axis with necks, each end of it turning in brasses fixed upon the tops of the two main upright standards of the press frame. C is the small cast-Iron pressing cylinder, having necks upon its axis turning iu sliding brasses, which can be aejusted so as to press with more or less force against the main cylinder B, by the screws, one of which is shown at D. EE is the endless web or blanket passing over and carried forwards by the pressing cylinder C, and over the web cylinder F ; the necks of axis of which cylinder turn in brasses, fitted into sliding carriages; with adjusting screws, one of which is shown at G, for stretching the web.
Upon the extended axis of the pressing cylinder C. is fixed the drum or rigger II, which is driven by a band I I, receiving its motion from the moving power. The plates JJ, Cc. are inked by the roller K, running into contact with them, in succession as the main cylinder revolves, and which roller is inked from distributing rollers L and the latter of which receives the ink in the usual man ner of machine typographic printing presses, from a trough and director, and which therefore need not be here shown. The ink is more uniformly distributed over the plates by a hand-roller, used by a workman. Another director N is supported by baskets at each end of it, to the main stand ards of the frame, one of which is shown at 0, in the usual manner of calico printing, and therefore need not be here shown. This last-mentioned director N scrapes or takes off the larger portion of the ink lying upon the sur faces of the plates, the remainder being removed by seve ral persons wiping it off in succession, and finally cleaning their surfaces, much in the same way as in copperplate printing. The paper properly moistened, may be either laid on the revolving web or blanket EE, in sheets, and be taken away when printed, or may be in the form of one or more long sheets, which may be previously wound upon the reel P; the neck on the axis of which turns in semi circular gaps or notches made in the top of standards affixed upon the frame of the machine, one of which is shown at Q, and passes beneath the directing roller R, until it reaches the press, after passing through which, and be coming printed, it finally passes over the roller S, to be taken away. The courses of the endless web or blanket EE, &c. and of the long sheets of paper, are indicated by the arrows, which arc shown accompanying them in their progress. The standards which support the necks of the rollers KLM and R, are omitted in the drawing, but must of course be employed.