Si 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Januaby, 



of the tender, as in the case nf tlie lommotive hefore descrilitd, 

 may he brought nearer the rails. Fdiirtlily — To em])hiy axles lor 

 raif»av carriafjes composed of two jiieces, one solid and the other 

 tubular, to slide over it ; one of a pair of wheels heinp; attached to 

 each piece, so that they may revoh e independently of each other. 



VIBRATING PISTON-ROD ENGINE. 



G. V. GrsTAFSsoN, of 15, William-street, Repent's-park, late en- 

 gineer, R.N. '■^ Improi'emeiitf! ill the xtniiii niyiiii;" 



The improvements relate, first, to " the mode of connectinsf a pis- 

 ton-rod to a piston hy means of a hall-and-socket joint." The ad- 

 vantajje of this plan over the old one (where the ]iiston-rod is con- 

 nected to the piston hy means of straps and keys like the crank 

 and connecting-rod) will easily he perceived ; a /niye hearing sur- 

 face, its facility for ada|)ting itself in the centre of the piston, being 

 bored and turned at the same time, and also the convenience for 

 liolding a lubricating substance, such as oil or tallow, and thereby 

 lessening the friction, and causing a less wear of the ball and socket. 

 Secondly, " The manner of keeping the piston tight within the 

 cylinder by the combined mechanical forces of steam and metallic 

 S])rings." The advantage of this arrangement will also be perceived 

 without difficulty: the skeleton of the piston is formed like a 

 wheel ; the nave receives the end of the piston-rod, from which 

 proceeds the arms, to the extreme ends of which a ring is attached, 

 and to which ring is bolted the top and bottom cover of the piston, 

 which for lightness should be made of wrought-iron ; within these 

 co\ers, and at the outer periphery, are fitted two metallic rings of 

 light construction, and kept in their jilaces by means of spiral and 

 horizontal springs, but not necessarily steam-tight, as that will be 

 effected by admitting steam into the chamber, which incloses the 

 packing-rings by means of a double acting valve; this will cause 

 a more uniform pressure on the packing-rings than could be effected 

 hy springs alone ; it also requires very little fitting and grinding, 

 onl)' the side of the ring nearest the cover : it has also another, 

 though perha]is not very great advantage, of partially pu/liiig, in- 

 stead of entirely piisliiiig the piston. Suppose the piston is moving 

 upwards, a portion of the pressure trom under it will be removed 

 to the upper cover, which is considerably above the centre of the 

 globe ; hence the pulling property, which in such case is preferable 

 to pushing : the same, of course, takes place on the down stroke. 

 Thirdly, " The construction of a moveable apparatus to he adapted 

 to the top or cover of the cylinder through which the pist(ni-rod is 

 to slide, and at the same time vibrate." The advantage of this 

 ap])aratus over the old slide-rest shaped one is, first, being curved 

 as to present nearly a rertangiilar base to the different positions of 

 the piston-rod, whereby the friction is considerably diminished ; 

 secondly, having nflat bearing surface to act against, instead of the 

 dovetailed edges in the old plan ; thirdly, and last, its facility of 

 kee])ing in contact with the bearing surface, which is effected in 

 condensing engines liy connecting the narrow chamber, between 

 the two slides, with the condenser, wherel)y the slides are kept in 

 their places hy the pressure of steam and tlie atmosphere : in non- 

 condensing engines this chamber should be in communication with 

 the atmosphere, which may he effected by causing the upper slide 

 to hear in the middle oiihj, allowing a passage to the chamlier under 

 it, whicli will also lessen the friction of the ujjper slide : it will be 

 perceived that the slides are i)ortions of circles, and consequently 

 easy of construction. And fourthly, " An a])paratus (or self-act- 

 ing damper) for regulating the draught of the flues aiul furnaces, 

 and thereby tempering the pressure of steam in the boiler, and also 

 giving such due notice of the state of pressure in the boiler as may 

 ])revent accidental explosion." This being a distinct apparatus, 

 may be used with or w ithout the other improvements, and is appli- 

 cable both for land and marine engines. 



The inventor states that, "a |)lan, somewhat similar in principle, 

 though ditt'ering in details, was tried many years ago, but in con- 

 sequence of the ill-ada])tation of the slides — soniewliat like the 

 slide-rent oi n turning-lathe — to the motion of the i>iston-rod, being 

 at riijht angles to the latter only at the dead points of the engine, 

 or top-and-bottom stroke, it was a very great defect." 



The three first imiirovements are shown in the annexed engi'av- 

 ing of a vertical sccti<in of the steam cylinder, o, the cylinder • 

 A, the skeleton of the piston, formed like a wheel for the purpose 

 of rendering it of light construction ; <■, a hollow cast-iron globe 

 fitted to the end of the ]iiston-rod and secured to it by a plug d, or 

 it may lie cast on to the end of the piston-rod : in the centre of 

 the piston is a hemisphei'ical socket, into which the globe c is fitted 



and secured to it by means of a cap e firmly bolted to the hemi- 

 spherical socket ; the arms have strengthening flanges on their 

 under s.des, and to tlie outer ring, at the extremity of the arms, is 

 bolted the top and bottom covers //i/, which, for liglitness, may be 

 made of wmught-iron. To render the piston steam-tight, two 



metallic rings are placed in the annular chamber between the 

 covers y g^ and held in their places by means of vertical and hori- 

 zontal springs, hut not necessarily steam-tight, as that will be 

 effected by admitting steam into this annular chamber of the piston 

 hy means of a double-acting valve, hy which a more uniform pres- 

 sure on the packing-rings is obtained than could possildy be effected 

 by springs alone : i is the cylinder cover, which is made spherical, 

 with segmental pieces to complete the arc of a circle ; /■■ is a seg- 

 ment slightly hollowed in the middle and bolted to the cylinder- 

 cover ; / are slides attached to the cups m n. To keep the radius 

 slides // constantly in contact with their bearing surface, the hol- 

 low space should be in comniiinication with the condenser, which 

 is effected by fixing a small tulie in any convenient place : in non- 

 condensing engines this space should be in communication with the 

 atmosjihere. 



It will be seen that as the piston ascends and descends, the 

 piston-rod will be enabled, hy the lateral motion of the radius 

 slides, to vibrate, and thereby act directly on the crank ; in conse- 

 quence of the angular position of the piston-rod the wear of the 

 cylinder would be greater on one side than the other, but this may 

 he avoided by giving to the latter an inclined position. It will be 

 perceived that this jieculiarity of the piston is of great advantage, 

 especially for horizontal engines, as the u-eiylit of the piston would 

 be supported by the jiressure, and consequently prevent an un- 

 equalizing wear of the cylinder and piston, which in common hori- 

 zontal engines cannot be avoided ; hence the vibrating piston-rod 

 is particularly ailapt^'d lor the screw-propeller and locomotive en- 

 gines. To prevent an unnecessary waste of steam, the sjiace 

 between the ]iiston and the cylinder cover, where the former is on 

 the tiq) stroke, as shown by the dotted lines, may be filled up with 

 hard wood and bolted to the cylinder cover. 



