Shaper Feed Mechanism
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Shaper Feed Mechanism
Shaper Feed Mechanism - The feeds of a shaper are usually obtained by means of a pawl and ratchet actuating the feed (lead) screw, (Fig.).
| A - Nut | E - Ratchet wheel | L - Rocker arm |
| B - Lead screw | F - Square for hand | |
| C - Connecting link | G - Driving disc rotates at same speed as the stroke (bull) wheel | |
| D - Reversible pawl | H - Driving pin adjustment in tee slot to very feed per stroke |
Shaper Work Table Feed Mechanism
| A - Cross Feed Lead Screw | E - Spring | J - Elevating Shaft |
| B - Power Feed Control Knob | F - Reversible pawl | |
| C - Detent pin | H - Ratchet wheel | |
| D - Connecting Rod | I - Cross Rail |
The (slotted) driving disc is driven by a gear connected to the bullwheel shaft, the gearing being such that the disc rotates at the same speed as the bull wheel (or bull gear).
The driving disc is linked by connecting rod to the rocker arm which carries a spring loaded reversible pawl. As the disc rotates it causes pawl to oscillate about the centre of the feed screw.
By offsetting the driving pin on the slotted disc, the rocker arm is made to oscillate sufficient to move the pawl over one or more teeth of ratchet and so transmit intermittent motion to the Crossfeed lead screw which moves the work table.
To reverse the direction of table traverse, the pawl is lifted by tbe knurled knob and turned round so that it moves the ratched wheel in the opposite direction.
When no feed is required, the pawl is lifted and turned through 90° so that the pin is out of the groove and the pawl is held clear of the ratchet.
The amount of feed to use on a given job will depend to large extent on the class of finish required, and whether a roughing or finishing cut is being taken. Feed on the shaper is measured in terms of the distance moved by the work for each cutting stroke made by the ram.
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