Diagram 2.

Fig. 1, diagram 1, is a side elevation of such a stamp. Fig. 2 is a front elevation, with one of the standards S removed to show the lifting gear in section, and the other part sectioned on line e, f to show detail of screw 28 for adjusting the guide or standard S. Fig. 3, diagram 2, is a rack modification for lifting heavy hammers. Fig. 4 is a plan of fig. 3, and fig. 5 is a section through the line G N of figs. 2 and 6 in direction of arrow h. Fig. 6 is a sectional elevation through the line c, d of figs. 1 and 5.

In figs. 1 and 2, B is the anvil block, S is one of the standards, D is one of the two brackets bolted to the back of the block B, C C are two upright back standards resting on the brackets D. The standards S are secured to the block B by bolts m, and slot holes allowing the guides or standards S to move in and out for taking out or reptacing the hammer H, or to take up wear and tear.

Referring again to figs. 1, 2, 5, and 6, o is a fiy shaft driven by a band on the fast pulley p. On this shaft is keyed a pinion q that gears into a spur wheel r, having fastened to it a ratchet wheel s; these rotate freely on the shaft t, on which is keyed a lever u, carrying a pawl v, retained by the spiral spring to on the adjustable pin x. As the pawl engages the ratchet wheel s the latter drives the crank shaft t in the direction of the arrow y, causing the crank to uncoil the band 2, at the same time coil up the band 4 and raise the hammer H.

As the crank z, with the lever u, return towards the bottom centre the pawl v catches against the shield 8, which serves to disengage the pawl from the ratchet wheel s, and keeps it out, allowing the ratchet wheel to continue its rotation without rotating the crank shaft t. Simultaneously with this the lever u forces the flipper bar 9-shown in broken lines through the shield 8-aside, and then strikes against the end of the second flipper bar 10, which serves as a stop, being supported by the spring 11 against the nut on the bolt 12. If it is desired to let the hammer fall downward pressure is applied on the treadle 14, carried by the levers 15, and connected to the flipper bar 10 by the rocking levers and down rod.

It will be clearly seen that the pawl v on the lever u is still kept out of gear of the teeth of the ratchet wheel by the outward extension of the arc-shaped shield 8 during the fall of the hammer, but when the latter is nearing the bed, the pawl passes off the upper end of the shield 8, and by the pressure of the spring w it again engages with the teeth of the ratchet wheel, and consequently the hammer is again raised to the top of its lift. Any rebound from spring 11 is resisted by the spring 13 on the opposite flipper bar 9. Near the outer end of the shaft o is a loose pulley k, and adjoining this is keyed a flywheel I, which is used for raising the hammer up by hand for tool-setting purposes. The automatic safety catch J is made adjustable in the slot.

Fig. 7 is a section of the standard S. The hammer can be adjusted for any height by means of screw 23 and crank-pin 24 in the slot of the crank Z. A rod 25 is connected to the treadle lever. On this rod is a sliding clip L, which overhangs the tail end of the catch J. As the treadle 14 is depressed to pull down the flipper bar 10 it also withdraws the catch J out of the path of the hammer before the latter commences to fall.

The springs 27, which are fastened to the treadle levers 15, are for keeping the flipper bar 10 in gear and the catch J under the hammer H.

Fig. 6 shows in section the detail of the parts used to effect the crank pin adjustment. The other extremity of this pin is provided with a nut which tightens upon a shoulder, allowing the bush part 34 to be free to rotate on the pin 24. On the outer end of the bush part 34 is another screwed collar 35; this tightens up against a pair of divided clip plates 36, between which is held the slotted connecting bar 37. In case of heavy hammers it may be preferred to use a toothed rack and pinion instead of bands.

Fig. 210.

Figs. 3 and 4 show this modification. H is the hammer to which a rack 38 is connected, this gears into a pinion 39 and is guided by the rollers 40. On the outer end of the spindle 6 is fixed another pinion 42, about half the size of the pinion 39, and into this works a rack 43, kept in gear by rollers 44. Frame 45 swivels on the spindle 6 in order to conform to the angular movement of the rack around the pinion 42, caused by the circular motion of the crank Z.

The power drop-stamp, fig. 209, is of similar construction to that seen at fig. 208, the only difference being that the latter would be worked by an overhead shaft. The stamp, fig. 209, is self-contained; the belt is attached to the hammer and brought over the flange pulley, which is kept continuously rotating. When the hammer is required to be raised the belt is drawn tight, and the pulley instantly grips the belt and raises the hammer. Both are largely used for finishing seamless-drawn hollow-ware, which, after coming out of the drawing or raising press, have certain imperfections in them, such as buckles or wrinkles and round corners, which need bringing up sharp. The machine, fig. 209, is also used in the manufacture of labels, and for embossment which requires boldly bringing out.

Another style of drop-stamp is seen at fig. 210. In this case the belt for raising the hammer is dispensed with, and in its place are introduced special rollers and a board. On depressing the foot treadle the friction rollers at the top are brought into contact with the board, thus raising the hammer. The board is automatically released and the hammer then descends. This drop-stamp is also used extensively for light forging work, such as articles used in the cutlery trades, locks, keys, pistols, etc. The movement of the hammer is controlled by a hand lever pivoted on the base block When a blow is required this handle is pressed down, causing the hammer to have a clear drop upon the work under operation, it then rises automatically to the top of its stroke, where it remains till the hand lever is again pressed down to have the blow repeated.