Page:The Kinematics of Machinery.djvu/415

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LARIVIERE AND BRAITHWAITE, DUCLO& 393

intended for a steam-engine. If these two inventors had only noticed how much more easily they could attain their object by a mere inversion of the chain such as is shown in Fig. 1, they would have spared themselves the trouble of scheming their complex substitute for the crank.

91.

Chamber-gear from the Conic Turning Cross-block. Plates XXX. and XXXI.

Of the two remaining positions of the conic double-slider chain, that upon c has not found any favour with the inventors of rotary steam-engines, while that upon a, the train (C^-C7*-) a , has been very frequently turned to account. This mechanism, which is that of the universal joint, has (unknown to the inventors) formed the basis of the six following machines.

Fig. 1, PI. XXX. Eotary steam-engine of Taylor and Davies.* The chambering is here carried out exactly as in Fig. 1, PL XXVIII, and the packing piece c is also added. The crank a, however, is made the frame, so that both the piston b and the chamber d (the latter carrying the block c with it) have pure turning motions. They correspond exactly to the two shafts of the universal joint, while the block c, which we have seen to consist of two revolutes with their axes at right angles, is the cross itself.

Fig. 2, PL XXX. Eotary steam-engine of Lariviere and Braith- waite.-f- Here a, the fixed link, is the chamber, and is made to enclose the two turning links I and d, and also the block c ; d is the only one of the moving links visible externally. The diaphragm in d, corresponding to the revolute 4, is carried across the diameter of the chamber, which makes the machine double-acting without rendering it necessary to make use of the space upon the left of the disc b.

Duclos { also made the link a the chamber (Fig. 3, PL XXX), he carried the spindle of I right through it, however, and made the link d merely a rotating blade or wing. It must not be forgotten

  • Newton, London Journal of Arts, &c. Conjoined Series, vol. xviii., 1841,

p. 97. Patent dated 1836 ; see also same work, vol. xix., p. 18. f Propagation Industrielle, vol. iii., 1868, p. 211. $ Propagation Industrielle, vol. iv., 1869. Patent dated 1867.