This machine is used to cut plane surfaces or straight grooves. Fig. 192 shows a type of planer much used. Work is secured usually by bolts and clips to the heavy table T, the surface of which is level. This table is made to move, by mechanism under the machine, back and forth along two level Y-shaped grooves B in the planer bed. The distance of travel of the table is governed by two adjustable stops EE which strike a lug of the reversing mechanism on the side of the planer bed and cause the two driving belts to shift on the pulleys GG. One of these belts is open and the other is crossed to drive the pulley in opposite directions. The middle wheel runs idly and merely facilitates the shifting of the belts.
All that part of the machine above the table is designed for holding the tool rigidly and for controlling its horizontal and vertical adjustment. The housings HH carry the cross-rail C which may be raised or lowered by the hand mechanism above the machine. The head D slides horizontally along the cross rail, and its parts are arranged for raising or lowering the tool, and for setting to tool at an angle to make cuts along the sides of a piece of work.
The tool is clamped by four bolts to the apron A, and it makes a cut only when the table travels to the right in the view here shown. When the work travels back to the left, a horizontal bolt J which hinges the upper edge of the apron A allows the tool to swing out of the way as it drags over the work. The tool may be gradually fed horizontally across the table or may be fed vertically. The feeding mechanism is marked Klprs. This mechanism moves the tool after it has finished its cut and when the machine is reversing. When a series cuts is finished across a piece of work, the tool point is lowered slightly by the handle N for another series.
Fig. 192. - Planer.
The driving mechanism of the planer table is designed to give the table a quicker motion for the return than for the cutting stroke. This is known as the quick return motion.