A few years ago, a new press was constructed by Mr. Medhurst, of London, the great recommendation of which was its simplicity, and consequent cheapness. In its general form it much resembled the iron presses in common use, the principal difference being in the manner in which the pressure was produced. This was accomplished by means of an ingenious arrangement of levers, differing so much from every thing previously employed in machinery, that the inventor described his contrivance as one which exhibited a new power in mechanics.
The principle upon which this press acts will be understood from the annexed sketch of the parts by means of which the impression is given. Instead of a screw, a plain spindle is employed: on the lower part of this spindle there is a swell or collar. A, into which the handle, or working bar of the press, B, is fastened. The upper part of this collar has cups or steps for the reception of two short iron props or, pins, C, D, which extend up to the head of the press, and are there supported by the points of two screws, E, F, entering sockets cut out in the heads of the pins, which are made of steel. When the platen is up, these pins stand in an inclined position, as represented in the annexed figure: but when the lever handle is pulled towards the spectator, so as to turn the spindle, the two screws remain stationary, while the props come into a vertical position, thus forcing the spindle and attached platen to descend, as if a screw were employed. It may be observed that, in the figure, G is merely a section of the head of the press, which is supposed to be looked at sidewise, to present the back and front projections, H, I, through which the screws pass. — Lardner's Cabinet Cyclopaedia, 1833.