Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . f the parts referred to, as exhibited in Figs. 2279and 2283, the nature of the motion above describedwill be at once most fully understood. To obviate the injurious effects of the shock of the tappetN against the lever 0, a connection is provided at />, on a similar principle to that formerly describedin reference to the connection of the piston-rod and the hammer-block; and in order to restrict thedow nward travel of the valve to the proper point, a check or bujfer-box S is provide
Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . f the parts referred to, as exhibited in Figs. 2279and 2283, the nature of the motion above describedwill be at once most fully understood. To obviate the injurious effects of the shock of the tappetN against the lever 0, a connection is provided at />, on a similar principle to that formerly describedin reference to the connection of the piston-rod and the hammer-block; and in order to restrict thedow nward travel of the valve to the proper point, a check or bujfer-box S is provided, consisting ofa small cylinder bolted firmly to the framing of the machine, within which a circular nut, screwed onthe lower end of the rod F, works as a piston, a few leather washers being interposed between thelatter and the closed or upper end of the cylinder. From the above description it will be obviousthat the lift of the hammer, and consequent intensity of the blows, depends simply upon the positionof the lever 0, in relation to that of the hammer-block when at its lowest point. The rod F, which. HAMMERS, STEAM, DIRECT-ACTING. 93 conveys the action of the lever 0 to the valve-lever R, is susceptible of rotatory as well as verticalmotion. This motion of rotation is imparted to it by means of a handle fixed to a short axis, work-ing in a bracket T bolted to the framing, and actuating a pair of small bevel-wheels q q. The nutthrough which the screw works forms the point of attachment between the rod P and the lever 0,the connection being effected by means of a short intermediate rod for the sake of insuring parallel-ism of motion. A pair of small spur-wheels r r (through the first of which the rod P works bymeans of a sunk feather) serve to transmit the angular motion of the rod P to a similar screwed rodV, situated parallel to and at a short distance from the former; the nut of the screw U forms thefulcrum or centre of motion of the lever 0, and the pitch of the threads
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Keywords: ., bookauthorbenjaminpark18491922, bookcentury1800, bookdecade1880
