Planer Open and Crossbelt Drive Mechanism with Rack and Spur Gears

Planer Open and Crossbelt Drive Mechanism with Rack and Spur Gears

Planer Open and Crossbelt Drive Mechanism with Rack and Spur Gears - In this mechanism of planer table drive, the open and crossbelts transfer motion from the countershaft (or electric motor) to thebul1 gear, which in turn moves the rack fitted under the worktable of the planer (Fig.).

 Two belts, one open and one crossed operate on loose and tight pulleys. Crossed belt* is used for forward or cutting stroke and the open belt for return motion. The open and *Crossed belt making a greater arc of contact on the pulley is considered better for driving the table on the cutting stroke.

Open Drive Mechanism with Rack and Spur Gears

Crossbelt Drive Mechanism with Rack and Spur Gears

Open and Crossbelt Drive Mechanism with Rack and Spur Gears

crossed belt drive mechanism permits operation of the gear train in such a manner that the table will travel slowly on the cutting stroke and travel faster on the return stroke. Pulleys keyed to the drive pinion shaft are called tight pulleys and those which turn freely on the shaft are called loose pulleys.

There are two tight pulleys and two loose pulleys. The larger tight pulley is used for the slower forward speed or cutting stroke drive and the smaller tight pulley is used for the quicker return stroke.

For obtaining continuous forward and return motion of the planer table both the open and crossed belts run continu­ally and are shifted back and forth by the belt shifter which is linked to the reverse lever.

During cutting stroke the crossed belt is on the tight pulley, the open belt is on the loose pulley and the position is reverse during the return stroke. Belt shifter reverse lever and the trip dogs: are responsible for relative shifting of belt automatically at the end of each stroke without stopping the machine.

Trip dogs are provided, one each at both ends of the planer table. At the end of each stroke, the trip dog meets against the reverse lever, actuates the belt shifter and thus the table movement is reversed.