Noun
spur gear (plural spur gears)
(mechanical engineering) The simplest type of gear wheel, with teeth projecting radially, parallel to its axis.
Due to the short distance between the lever arm link boss and the pivot pin and the difference between the effective radius of the sector gear and that of the spur gear, any motion of the Bourdon tube is greatly amplified. Source: Internet
This has a spur gear that engages the sector gear (7) and extends through the face to drive the indicator needle. Source: Internet
Post mills sometimes have a head and/or tail wheel driving the stone nuts directly, instead of the spur gear arrangement. Source: Internet