1028

THEORY AND PRACTICE OF ENGINEERING.

Book 11.

Fig. 1569.

PROVING IRON WORK, USED AT MENAI.

Machine for bending Iron Plates is of the greatest service for the manufacture of boilers:on the left of the figure are two riggers, one tight and the other loose, for driving the twocylindrical rollers, the speed of which is regulated by the spur-wheel and pinions; on theright is the fly-wheel placed on the driving shaft, which maintains a steady motion whenthe machine is in use. The curvature to be given to the iron plate is regulated by a largescrew attached to each cylinder, which brings them nearer, or drives them farther from eachother, according to the required bend.

Fig. 1570.

BENDING IRON PLATES.

Machine for making Screw Bolts. — A backward and forward motion is given to a hollowshaft by three driving pulleys; when the strap is on that to the left, the spur-wheel andpinion put the machine in motion, and communicate it to the chuck which holds the steel

Fig. 1573.

ELEVATION.

Fig. 1572.

END VIEW