sinker

n. One who, or that which, sinks. Specifically: (a) A weight on something, as on a fish line, to sink it. (b) In knitting machines, one of the thin plates, blades, or other devices, that depress the loops upon or between the needles. [ 1913 Webster ]

Dividing sinker, in knitting machines, a sinker between two jack sinkers and acting alternately with them. --
Jack sinker. See under Jack, n. --
Sinker bar. (a) In knitting machines, a bar to which one set of the sinkers is attached. (b) In deep well boring, a heavy bar forming a connection between the lifting rope and the boring tools, above the jars. [ 1913 Webster ]