What is "treadle"

Treadle \Trea"dle\, n. [OE. tredyl a step, AS. tredel. See Tread.]

1. The part of a foot lathe, or other machine, which is pressed or moved by the foot.

2. (Biol.) The chalaza of a bird's egg; the tread.

"lever worked by foot," c.1400, from Old English tredel "step, stair, sole of the foot," from tredan "to tread" (see tread (v.)) + instrumental suffix -el (compare handle (n.)).

n. A foot-operated pedal or lever that generates circular motion. vb. To use a ''treadle''.

1. n. a lever that is operated with the foot [syn: pedal, foot pedal, foot lever]

2. v. tread over; "the brickmaker treadles over clay to pick out the stones"

3. operate (machinery) by a treadle

A treadle [from OE tredan, to tread] is a part of a machine which is operated by the foot to produce reciprocating or rotary motion in a machine such as a weaving loom (reciprocating) or grinder (rotary). Treadles can also be used to power water pumps (as in the treadle pump), or to turn wood lathes (as in the pole lathe). In the past, treadles have been used to power a range of machines including sewing machines, looms, wood saws, cylinder phonographs and metal lathes. Along with cranks, treadmills, and treadwheels, they allowed human and animal power of machinery in the absence of electric machinery.

In railway signalling, a treadle is a mechanical or electrical device that detects that a train axle has passed a particular location. They are used where a track circuit requires re-inforcing with additional information about a train's location, such as around an automatic level crossing, or in an annunciator circuit, that sounds a warning a train has passed an exact point. The important difference between a treadle and a track circuit is that while a track circuit detects a train over a distance as long as several kilometres, a treadle provides pin-point detection.