What is a transmission shaft?

A transmission shaft (also known as shaft) is a rotating machine element with circular cross section. Shaft is used to transfer rotary motion from one point to the other point.

Shaft is generally mounted with gears, pulleys and sprockets. With the help of these mountings power is transferred to the other shaft or to the point where it is actually used.

One the basis of application shafts are given different names. However, the purpose remains same i.e. transfer of torque, motion and power.

Spindle

Spindle is a short rotating shaft. The name spindle is originated from the round tapered stick of the spinning wheel.

Axle

Axle is a shaft which supports rotating elements like wheels.

Countershaft

A counter shaft is a shaft which is connected to the main shaft with the help of a pair of gears. Since, it rotates opposite to the direction of rotation of main shaft, it is known as counter shaft.

Jackshaft

Jackshaft is the intermediate shaft between to rotating shafts. Its sole purpose is to transfer power from one shaft to the another.

Line shaft

A line shaft is a combination of shafts which are joined axially to one another (with the help of couplings). Line shift is mounted with several pulleys so that power from the one line shaft can be used at several points where it is actually used.

Line shaft are now replaced by group drives hence, they are obsolete now.

Image credits:

1. Line Shaft: By Atelier Hermann WalterBernhard Müller (* 1860; † 1930)Karl Walter (* 1877; † 11 October 1940) – Christoph Kaufmann: Fotoatelier Hermann Walter. Leipzig 1918–1935. Pro Leipzig, Leipzig 2010, ISBN 978-3-936508-61-1, Public Domain, https://commons.wikimedia.org/w/index.php?curid=12079454
2. Counter Shaft: http://mel0207lsprod.blob.core.windows.net/uploads/global/ls/content/35176/drivetrain/how/manual_4.html
3. Axle Shaft: By No machine-readable author provided. Pantoine assumed (based on copyright claims). – No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=812624