At the left of the machine, attached to the crank shaft, is the crank, A (Fig. 4), which by means of the connection, D, gives vertical motion to the sliding piece, E, which works upon the angle guide, F. At the top of the sliding piece, E, and at either side, are connected the short links, II (Fig. 8), by which motion is imparted to the cranks, I (Fig. 4). these in turn actuating the two auxiliary crank shafts, J, which pass along at either side of the main shaft. C, and by means of the cranks, K K, and their con nections, give motion to the blank-holder slide. These various connections operate to make the " dwell " of the blank-holder shown by the diagram, Fig. 7, at the time the sliding piece, E, is at and near the upper limit of its motion, and While the slide carrying the punch is near the lower limit of its motion, which is when the actual drawing of the blank is being done. The diagram, Fig. 7, at the left shows the positions of the various parts when the sliding piece, E, is at its lowest point, and the blank-holder raised to its ex treme height, while the diagram at the right shows the various positions when the dwell of the blank-holder is just beginning, the small movement of the sliding piece E, during this period, acting simply to swing the connections, H, H, upon their centers, as shown by the dotted lines, but producing no perceptible movement of the blank-holder, while the cranks, K, K, and their connections being in the same straight line, which is the line of thrust.
the moving parts are relieved of all strain, thus avoiding undue wear, and making the full power of the machine available at this time, just when it is needed for the punch.
One object in making the piece, E, so heavy is that it may act as a counterbalance for the other moving parts. In operation, the blank, which has previously been punched or trimmed to the desired size and shape, is placed over the die, and the blank-holder then first descends in advance of the punch until it rests upon the blank, and exerts a heavy pressure all around its outer edge. The punch then descends and forces the middle portion of the blank into the die, drawing the metal out from between the face of the (lie and blank•holder, which by its pressure prevents any kinking or buckling of the sheet. it is important to secure even pressure all about the blank, and this is provided for by making the blank-holder in two parts, and putting in the four screws, a, a, a, a, one of which being placed at each corner of the blank-holder, and provided with suitable nuts, the pressure can be made uni form all over the face of the die. These
screws serve also for the vertical adjustment of blank-holder to suit different dies, the range of adjustment provided for being 8 in. The punch can also be adjusted vertically by Corning the shaft carrying the pinion, d (Fig. 4), which engages with the bevel gear shown, this bevel being at the bottom of a large screw which affects the movement by means of it slide ; the four bolts, shown above the pinion and on either side of the shaft, bind ing all tightly together when the proper adjust ment has been made, so that no alteration can take place without first loosening them. The extent of this movement is 6 in. The long connecting-rod at the left of the machine, and extending from near the top to the bottom, gives motion to the device within the base, by which the blank is forced up out of the die when released by the blank-holder. The main crank shaft, C, is 11 in. diameter, the gear which is keyed to it at the right being 7 ft. 7 in, diameter, 12 in. face, and 4 in.
pitch. It is driven by a pinion on the intermediate shaft, the large intermediate gear being driven by a pinion, which is not keyed directly to the engine crank shaft, but to a sleeve which forms a portion of a Dill friction clutch, by which the motion of the press is controlled, a small movement of the lever starting or stopping the press promptly and smoothly, the clutch being so arranged that the movement of the lever which releases it applies a brake, which promptly arrests the motion, and thus the press can be handled with. the greatest facility.
The engine is of simple constructioji, has a plain slide valve with throttling governor, and has the crank pin for actuating the valve fixed to a disk, which is at the end of a return crank attached to the main wrist-pin. The disk is so mounted upon the return crank that when the engine is turned in either direction by hand, the disk so adjusts itself by turning on its (-enter that the valve is set for running in the direction in which the engine has been turned. without any further attention being required. The cylinder of the engine is 12 x 14 in. and it is designed to run 250 revolutions per minute, which gives the machine a speed of 5 strokes per minute, the gearing being proportioned 50 to 1. The press stands about 14 ft. high and weighs about 60 tons.