The annexed engraving is a horizontal section of a new and improved mode of regulating or adjusting the packing of pistons, so that the packing, when loose within the cy-linder.may bemade to work steam-tight without removing the cylinder cover. It is the invention of F. I. Palmer, of Greenbush, Rensselaer, Co., N.Y.who has taken measures to secure a patent for it The object above specified is attained by means of a cam inside of the piston, which moves as it is turned, and presses against springs that rest against the packing rings, so that the rings are pressed steam-tight around the inner surface of the cylinder. The mode of regulating thepacking is performed by means of a key which is inserted through an aperture in the cylinder-head, and turns the cam as may be required, without any necessity of removing the former. The nature of the improvement, however, will be bettef understood by the following reference to the engraving i A is the piston-head; B B are two packing metallic rings,one within the circumference of the other (there is another which is removed) so placed as to ;l break joint," that is the part where the one is cut is not allowed to coin-cide with the, $pmtm* of tiia other; these rings are forced outwardaby springs, G G GG, which press against the circumference of the inner ring. The springs are acted upon by pins,FFF F, which rest against the curved projections, b b b b, of a notched cam, C. This cam ismadetomoveroundbya key, and it is held in any position to which it may be turn- ed by a ratchet wheel (seen in dotted lines underneath) which is fixed. On the underside of the notched cam plate, C, there is a pawl, D, attached, which takes into the several teeth of the ratchet wheel, as the cam is moved round, and this holds, as shown, the said cam in any position to which it may be turned. The pawl is kept in contact with the teeth of the ratchet wheel by a spring,E Now, if the cam is turned from left to right, thebuttpins, FF F F, will be moved outward, and acting upon the springs, G G G G, the packing rings will expand and thus fit steam-tight against the interior of the cylinder. The mode of turning the cam as mentioned before, is by means of a forked key which fits in the apertures II. J J J J are nuts forreceiving the screws that fasten down the top plate; F- F' F' F', are butt collars belonging to the pins, F F F F, and against which the extending curves of the earn, C, act to lorce the pins out and press the springs, G G, against the metallic packing rings, B B. The under plate of this piston is screwed '? down to cover all the interior, and there are itwo openings in it through which the key j spoken of is inserted into the holes, I I, and the projecting pin between these two orifices passes into the hole of the key, so that the cam is easily turned to the desired point, without taking off the cylinder cover. The holes in the cylinder cover are kept tight by screws, bolts, or other means when the engine is at work. This is a good improvement on pistons, and it will be appreciated by engineers. More information may be obtained by letter addressed to Mr. Palmer.
This article was originally published with the title "Piston Head Packing" in Scientific American 8, 8, 60 (November 1852)