MARINE ENGINES.

473

otherwise it would be impossible for the best mechanic to adjustthe one to the other in a limited time. The points of contact aretaken on raised Strips, cast or forged on as the case may be, forminga V section, with flat parts cut across the shaft, and the fracture isdrawn together by means of the longitudinal flanges and bolts.There are four series of strips in the length of the coupling, makingsixteen points of contact in all. These couplings can be fitted withkeys for taking the shearing strain; but it is evident that cuttingand filing up key beds on the shaft in a heavy seaway would be awork of difficulty, and therefore in emergencies the necessary amountof grip can be obtained with a series of cupped set screws and nutsrecessed in the coupling, considering that the coupling of the V sec-tion takes the greater part of the torsional strain. To lighten thesecouplings so that they can be easily adjusted, we propose makingthem of cast Steel . Wrought iron or even cast iron can be used,but the latter will be of considerable weight; and perhaps the moreexpensive material may not be considered too much, when weremember that the light coupling is more easily handled on boardship.

The pillow Blocks are of cast iron, lined with white metal; theyare quite plain, and are fitted with a cover, parting at the centreline. Oil cups are cast on the top of the covers, fitted with pipes,syphon wicks, and light cover. The base of the block is quite

Fig. 354.—Pillow Block for Shafting.

A, Pillow Block, b, Cover for do. c c, Bolts and nuts. d, Oil cup.

flat, and is generally bolted down to wooden beams placed on thetop of wrought-iron Standards, which are carried up from andstrongly rivetted to the floor plates. The pillow block for receivingthe thrust or forward motion of the line of shafting imparted by theaction of the screw propeller—this push being always in the direc-tion of the path of the vessel, whether moving ahead or astern—