306

DETAILS OP SCREW ENGINES.

by Fig. 171, being an ordinary exampleadopted universally. The cup is almost

Fig. 171.

ORDINARY TALLOW LUBRICATOR ROB STEAM PISTON .

globular, and the valve the disc type, with ascrewed projection below it as a guide andpassage for the lubricant, as shown by thesection above the flange. Obviously, onraising the valve from its seat, the tallow canflow through the hollows, and, as the valve isnot withdrawn entirely, it can be as readilyclosed.

In some instances stop cocks are used belowthe cup, and the form of the latter is notalways globular, but often cylindrical, with afancifully formed cover, as shown by Fig. 172.Lubricators also have been fitted with non-return valves to prevent the waste of thetallow, and others with double reservoirs andcocks for the same purpose.

The continual and economical lubrication ofthe crank and cross-head pins have oftenengrossed the attention of engineers, and to

the present the suspended can and motionwiper are the best means yet known. An

Fig. 172.

PLUG COCK LUBRICATOR

illustration of these details is represented bFig. 173. The can is fitted with a projection,

Fig. 173.

SUSPENDED OIL CAN AND MOTION WIPER FOR CONTINUOUSLUBRICATION.

which contains the extremity of a certainquantity of wick or other suitable materialwithin the can. The connecting rod hassecured on it two pieces of brass, that wipe