PLATE VIII.-Hydraulic Car Wheel Press. friction on the ram, but also brings the wear of movement upon the ram instead of in the cylinder. In cast iron cylinders it is still the custom to use a brass or copper lining on account of the metal being of a porous nature; continual pressure permeates the body and eventually parts the casting, the lining also prevents the formation of rust. This system of lining cylinders has in many cases and for several causes proved unsatisfactory. Not only does the pressure at times, through the breaking of a bottom packing or some such cause, work in between the walls of the cylinder and the lining, producing a buckle therein, but it also necessitates the use of a cup packing on the end of the ram, which brings the wear of movement upon the cylinder, the most expensive part of the press. In using the steel cylinder and the "U" packing in the throat, there is no necessity to line the cylinder with brass or copper, for the packing, being in the throat or at the outer end of the cylinder, and being atmospherically tight, the element of rust formation is reduced to a very minute amount. A pressure gauge is attached to the cylinder which indicates the applied pressure and prevents any imperfect fit being used unknown to the operator, or overstrain exerted on the tool. HYDRAULIC CAR WHEEL PRESSES. Plates VIII and IX show the popular types of hydraulic car wheel presses, which are made with various modifications to operate with hand or power pumps, with pumps of various multiple and sizes of pistons, with driving mechanism at various angles to the machine, capacities, sizes, etc., etc. The most improved type of pump is shown on plate IX, which is of automatic design, and is a rapid delivery high grade pump in all its details. The small vertical lever shown, inclined at an angle in the center of the cut completely governs the movement of the ram. When in the position shown, the ram is forced out at its low pressure or quickest speed, which continues until the ram comes in contact with the resisting force and the applied pressure reaches about one-fourth the maximum. At this point the automatic trip shown by the small yoke with the suspended weight ball on the side of the pump body trips the low pressure piston with a steel rod passing through the suction pipe, forcing the suction valve off its seat. Thus the low pressure piston continues its stroke, but makes no delivery of water, while the high pressure piston, shown on the right side of the pump, continues the pressure up to the maximum, or until the desired limit is reached. When the applied pressure has gained the desired amount, the lever, upon being brought forward about twenty-five degrees, opens a patent double seat valve, which releases the pressure, and the ram is drawn back in the cylinder by the counterweight at the end of the press, the water returuing to the reservoir through a return pipe shown in a vertical position at the back of the pump body. A safety valve is included in the pump, which prevents straining the press beyond its capacity, and a pressure gauge indicates the energy with which the wheel is forced upon the axle. HYDRAULIC PUNCHES. Plates X and XI present a very useful tool in both bridge and shop work where occasion requires a portable tool for heavy punching. Its operation in pumping and releasing is exactly the same as in the regular hydraulic jack. Its interior mechanism is, however, entirely different. Plate XI shows the design of the pump and arrangement of valves, with the exception of the pressure valve, which is concealed behind the section line, the valves being laid out in the pump about one hundred and twenty degrees apart. The two valves shown in the sectional view are the suction and release. With the rack and pinion the ram is brought down rapidly with one stroke until the punch rests upon the work, when a few strokes of the pump lever forces the punch through the piece. PLATE X.-Hydraulic Punch. Turning the pump lever over and forcing the piston downward an additional stroke, the same manner as in a hydraulic jack, places in contact the shoulder shown upon the piston rod with the release valve, which is forced off its seat and the liquid is returned to the head or reservoir by driving the ram back into the cylinder with the rack and pinion mechanism. The pump and head are made of a very high grade and hard bronze metal specially prepared for this purpose, and the body is made of steel, which considerably reduces the weight and yet obtains the requisite strength. Many modifications in the details of the jaw of this tool are made for a great variety of purposes, such as punching angles, tees, angle bars, I beams, T rail webs, etc., and the depth of jaw in the several designs varies from 11⁄2 to 121⁄2 inches. HYDRAULIC RAIL BENDERS. Plate XII introduces a further application of the principles of the hydraulic punch type of tool modified to suit the bending of heavy rail. Here the pump details are the same as before, but the sectional view instead of showing the suction and release valves the same as Plate XI, presents to view the suction and pressure valve, the release valve in this case being concealed behind the line of section instead of the pressure valve. With the rack and pinion the ram is brought forward with one stroke of the lever in contact with the rail, when a few strokes of the pump lever makes the nec |