The engineer's sketch-book of mechanical movements, devices, appliances, contrivances and details employed in the design and construction of machinery for every purpose

by Thomas Walter Barber

Section 65.—QUICK RETURN MOTIONS.

Employed for machines having a slow movement one way, and a quicker return movement.

[1195]. Slot lever and crank motion; gives a varying speed, quickest when the crank pin is at the bottom centre, and slowest when at the top, with a slight pause at each end of stroke.

[1196]. Whitworth’s motion. The pin A in the wheel B travels eccentrically in the crank disc, which is eccentric to the fixed boss on which the driving wheel B runs, so that the radius of the driving motion of the pin varies as it revolves and it travels up and down the slot in the disc.

[1197]. By two belts, one open and one crossed, and driving drums of different diameters.

[1198]. By two belts, one open and one crossed, but driven by the same drum. The middle pulley is loose, the left hand pulley is fast to the spur wheel, and the right hand pulley to the spur pinion.

Segment gear, gearing alternately with the internal ring and the central pinion. See [No. 724].

See [Section 74].

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