- Rack and pinion
A rack and pinion is a pair of
gears which convert rotational motion into linear motion. The circular " pinion" engages teeth on a flat bar - the "rack". Rotational motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel.For example, in a rack railway, the rotation of a pinion mounted on a locomotiveor a railcarengages a rack between the rails and pulls a trainalong a steep slope.
The rack and pinion arrangement is commonly found in the
steeringmechanism of cars or other wheeled, steered vehicles. This arrangement provides a lesser mechanical advantagethan other mechanisms such as recirculating ball, but much less backlash and greater feedback, or steering "feel". The use of a variable rack was invented by Arthur E Bishop, [cite web|title=Rack and pinion variable ratio steering gear|publisher=Google Patent Search|url=http://www.google.com/patents?vid=USPAT3753378&id=bTEwAAAAEBAJ&dq=pinion+%2Bininventor:Arthur+ininventor:E+ininventor:Bishop&jtp=1|accessdate=2007-03-22] so as to improve vehicle response and steering "feel" on-centre, and that has been fitted to many new vehicles, after he created a hot forging process to manufacture the racks, thus eliminating any subsequent need to machine the form of the gear teeth.
For every pair of conjugate involute profile, there is a basic rack. This basic rack is the profile of the conjugate gear of infinite pitch radius."ANSI/AGMA 1012-G05", "Gear Nomenclature, Definition of Terms with Symbols".] what
A generating rack is a rack outline used to indicate tooth details and dimensions for the design of a generating tool, such as a hob or a gear shaper cutter.
* [http://www.brockeng.com/mechanism/RackNPinion.htm Another animation] of the rack and pinion mechanism.
Wikimedia Foundation. 2010.