MINT 



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but it is believed that 'under all circumstances it will be found wise to adhere to the 

 plan of cutting out a single blank at each descent of the punch. For bronze it is well 

 to obtain five or more blanks at each blow, but the limited variation of weight allowed 

 by law on blanks of the precious metals would render this false economy. Fig. 1536 

 represents one of the twelve cutting-out presses, which are all driven by a wheel pro- 

 vided with a series of cams on its outer rim ; one of these cams is in the act of striking 

 the friction-roller, F, which is attached to, and forms part of, the lever D. D is fixed 

 to an upright shaft, which at E is cut with a screw-thread working into a female-screw 

 fitted into the main-shoulder of the press at c. If now the cam strikes F, and throws 

 it outwards, it causes the shaft D to take a part of a revolution, and in so doing the 

 screw E makes it rise and carry with it the block N, whose tendency to circular motion 

 is prevented by a plug fitting into its groove, and fixed in the guide o. The lower 

 end of N carries a screwed cap, 



H 



which supports the cutting-out 

 punch, so that when E rises it 

 carries the cutting-out punch 

 through just the same distance 

 that itself travels upwards. The 

 cutting-out punch is now ready 

 for action, and is released by the 

 continued revolution of the wheel ; 

 but, as it could not fall with suf- 

 ficient force of itself, assistance is 

 rendered by the pressure of the 

 atmosphere, as will be seen by 

 the following arrangement. The 

 lever D is provided at H with a 

 loop of iron travelling on a screw, 

 so that it may be moved farther 

 from, or nearer to, the centre of 

 action, and thus admit of the in- 

 crease of power. This loop of 

 iron is represented by H, and is 

 continued by a rod of iron across 

 the upper part of the room, and 

 through a hole in the wall to a 

 system of levers, from which a rod 

 is suspended, the lower end being 

 connected with a piston working 

 in a chamber. The chamber is an 

 hermetically -closed vessel secured 

 to a stone firmly fixed in the 

 floor. The piston works in this 

 chamber, and is covered with 

 about 2 inches of oil, which pre- 

 vents the access of the atmosphere 

 by leaks to any part beneath the 

 piston. If the piston, therefore, 

 bo raised from the base of the chamber, a vacuum is produced in that portion from 

 which the piston is removed, and consequently the atmosphere presses on the surface 

 of the oil, which in its turn presses on the piston, and carries it down ; in its fall the 

 piston pulls down the cutter, which has been raised ; for the same blow which raises 

 the cutter also raises this piston ; therefore, when the cutter is raised the workman places 

 the fillet from which blanks are to be cut on the bolster, shown beneath o, and holds 

 it firmly while the cutter descends and punches out a blank, which falls through the 

 bolster into a drawer. By the time that the down-stroke of the cutting-out punch is 

 complete, the wedge B has entered a slit in the spring H, and strikes the spring, thus 

 throwing the machine back, and preparing it to start when the cam shall strike the 

 friction-roller F. The point at which B may strike K is determined by a screw near 

 the left hand p. The upright shaft D, -which is partly hollow, terminates at a flat 

 cogged wheel, and the upper part of E is made to pass into D ; while at is is an 

 arrangement which serves to detach or connect these pieces, that the cutter may upon 

 occasion be used by the hand by means of the lever T, as well as to admit of the 

 necessary alterations, as the punches, by regrintling, become shorter. The cutting-out 

 punch, when it rises, carries with it the fillet from which the blank has been punched, 

 until the fillet comes against the guard b, which detaches it. 

 The fillets from which the blanks have been punched have the appearance of ribbons 



