Page:The Kinematics of Machinery.djvu/565

 PRESSURE-ORGAN FAIRS,

�543

�chain guided in a pipe Fig. 380 and the spring brake Fig. 381. The same principle is also utilised in certain machines for the manufacture of wire- work. It is unnecessary, however, to treat these pairs as an order (F, t ), for in all cases the flectional element of the pair may be considered as a pressure-organ. They therefore are all included in the order ( F, q ).

��FIG. 378.

�FIG. 379.

�Another and very remarkable pairing of Q is that with T. This can be very easily carried out if the latter have the form T z or T r , if it be made, that is, as some form of chain. The "Paternoster " pump, whether with buckets or piston discs, the grain carriers of mills, the ladders of dredging machines, etc. all furnish illustrations

���FIG. 380.

�FIG. 381.

�of this pairing. It would be possible to indicate by a special sign the peculiar construction of the chain, calling a tension- organ provided with scoops T v for instance. This particularity is not necessary, however, for if a symbol show a pairing between T z and Q it may be held to indicate that the tension organ is arranged in such a way that the pairing is possible. In some cases also no special alteration of the form of the tension- organ has to be made for this purpose, as in Vera's " rope-pump," where a mere rope T t lifts water by adhesion.* All these pairs together form there-

elder Brunei. It is certainly older than his time, however. See Langsdorf, ii., p. 220; Hachette, Traiti EUmentairt, p. 134. R.
 * The rope-pump, or water-rope machine, has been frequently ascribed to tho

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