Guiding member 1 is reciprocated along fixed guide 2 by cross- head 11 through bellcrank lever 4 which is pivoted to the cross- head at a. Cross-head 11 slides along fixed bars 9 and 10, and is reciprocated by cam 3 in whose groove roller a of the cross- head rolls and slides. Roller d, at the lower end of bellcrank lever 4, engages the slot of pivoted lever 5. The stroke of member 1 depends upon the angle of inclination of slotted lever 5. This angle of lever 5 is controlled by cam 6 in whose groove g roller b of lever 5 rolls and slides. Cam 6 rotates about fixed axis A and is driven by worm 7 and worm wheel 8. While roller b of lever 5 is passing over concentric circular portion f of groove g in cam 6, lever 5 has a dwell and guiding member 1 has its maximum stroke. Then the stroke is gradually diminished as roller b passes along portion c of groove g, reaching its minimum value at point e. After this point, the stroke of member 1 gradually increases again.
$3173$CmL,ML$