Engineering Wonders of the World
Volume I

ONE OF THE GIGANTIC UPRIGHTS. 25 FEET HIGH, 12 FEET DEEP, 30 INCHES WIDE. 384 ENGINEERING WONDERS OF THE WORLD. ferring a belt from one pulley to another. The belt is here replaced by multiple-disc pneumatic clutches on the shaft of the 100 horse-power motor. Compressed air, controlled by valves operated automatically by the move- ments of the table, bring the clutches into action alternately, transferring the drive from one to the other at the end of a stroke. The last element in the driving train is a pair of gigantic pinions, called bull wheels, which engage with a rack on the underside of the table. The size of these pinions may be in- ferred from one of our illustrations. Electricity and pneumatic pressure operate all the complicated trains of mechanism for raising, traversing, and feeding the cutting tools ; and in spite of the huge scale of the planer, adjustment is possible to a very small fraction of an inch. The movement of a handle regulates the length of the table’s stroke to suit the size of the object which has to be planed or slotted. By means of cranks which work in combination a tool can be given a composite movement, so as to cut at an angle to the horizontal. Another interesting feature is the safety mechanism, which prevents the end of a stroke could not conveniently be table being moved while a tool is cutting accomplished by the ordinary method of trans- transversely, and vice versa. THE ENORMOUS PINIONS, OR MOVE THE TABLE BULL WHEELS, WHICH TO AND FRO. Note.—The illustrations were kindly supplied by the builders of the machine, Messrs. Niles Bement Pond of Philadelphia.