A. A gear-wheel in the form of a continuous screw. (Fig. 10.)
Q. What is a sprocket-wheel?
A. A toothed wheel that engages the links of a chain. (Fig. 11.)
Q. What is a spur-wheel?
A. A gear-wheel with teeth parallel with the axle of the wheel. If in Fig. 7 the rack were in form of a wheel, it would be a spur-wheel. (The pinion is also a spur-wheel.)
RACK AND PINION.
Fig. 7.
MITRE GEAR.
Fig. 9.
BEVEL GEAR.
Fig. 8.
WORM GEAR.
Fig. 10.
SPROCKET WHEEL AND CHAIN.
Fig. 11.
Q. Point out or describe the location of the following parts of a seacoast carriage: