Page:The New International Encyclopædia 1st ed. v. 09.djvu/563

* HAMMER. 509 HAMMER. type of liaiiiimr is opeiaU'd by a cam or cc- ceiiti'ic (si'L' C'..m'; Ecc'ENTHic), wliiili swings up tile head end one or two tect and lets it drop. An anvil placed so as to receive the blow is an essential pari of the nieclianisni. Various modi- fications of tliis simple device have been devised, but, like the original form, they have become ])raetically obsolete in forging operations, having been replaced by the ilirectacting steam ham- mer. This tool was invented bj- .James Nasmytli, wlio first conceived the invention in 1S39. but did not patent it until lSt2. Sleanwhile a steam hanuner had been actually built at the iron- works of Le t'reusol, France, the- idea of which, according to English writ'/rs. had been obtained from Nasmyth's preliminary sketches, to which the French builders had had access. Be this as it may, the fact is that the first Nasmytli hammer was erected at the Bridgewater Foundry at Patri- croft, near Manchester, England, in 184.'!. This hammer consisted of two vertical uprights or columns surmounted by an entablature, which carried an inverted vertical steam cylinder miil- way between the two columns. In this cylinder was a piston, with a piston-rod projecting down- ward between the two columns and carrying at its end a casting which formed the hammer proper. An anvil block occupied the space lie- tween the feet of the columns, and received the blow of the hammer. To operate the hammer steam was admitted to the cylinder below the piston, w'hich raised it with its attached jiiston- rod and hammer to any height desired, limited by the height of the cylinder; wlien at the desired height the steam was allowed to escape into the air. and the piston and its attachments fell by gravity. The force of the blow depended upon the weight of the hammer and the height of the fall. The hammer was worked by means of an ordinary slide-valve and a long lever, requiring great labor and constant attention in order to give the blow required; so that some contrivance capable of adjustment was necessary in or<ler to have complete command over the power of the blow, and in order that, (he instant the blow ■was struck, the block should rise again, so that not only no loss of time should ensue, but that the heat in the mass of iron on the anvil might not be reduced or carried off by the cold face of the block. The peculiar difficulty of securing a true automatic arrangement will be seen when it is considered that the instant of percussion must vary with almost every blow that is striick: for the piece on the anvil becomes thinner and thinner by each succeeding blow, and in flat = bars a blow is first given on the flat side, and (hen on the edge, the difference in the fall of the hammer in the two cases being oftentimes several inches; and further, that the liammer must be under i)erfect control at all times. Nasmyth, after many and protracted trials, failed to produce the motion required, and, as a consequence, the whole hammer scheme was on the point of being abandoned. In this dilemma, and during Nasmyth's absence from the works, his partner, Gaskell, applied to their engineering manager, Robert Wilson, who afterwards became managing partner and successor to Nasmyth, to endeavor to solve the problem which had hith- erto baffled the skill of Nasmyth. Wilson took the matter in hand, anil in little more than a week a mechanism was invented and attached to a hammer upon which former experiments had been made, and was at once found to answer most admirably every condition re- (|uired. I'nder the inllucnce of this very beau- tiful mechanical deicc cvciy variety of blow ftTEA.M HAM MER. Set!tiii showing cylinder and valve meohaniflm. could be given — from the gentlest tap to the heaviest blow within the compass of the hammer — and that, too, perfectly self-acting in every re- spect, the long lever and the hard work before STEEL-UAMMEn. For forging iron and stw'l. referred to being now entirely banished. By simply altering the position of the tappet lever by means of two screws, a blow of the e.vact force required could be produced and continued so long as steam was supplied. On August IS. 1843, the first hammer was delivered to the Low- Moor Iron Works, near Bradford. Yorkshire, and gave such satisfaction that orders for this re- markable tool began to flow in from all parts of the country. The hammer remained in this condition, with the exception of a few minor details, from 1843 to 1803, when Wilson (who had become connected with the Low ^loor Iron