- Rack and pinion
A rack and pinion is a pair of
gear s which convert rotational motion into linear motion. The circular "pinion " engages teeth on a flat bar - the "rack".Rotation al motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel.For example, in arack railway , the rotation of a pinion mounted on alocomotive or arailcar engages a rack between the rails and pulls atrain along a steep slope.The rack and pinion arrangement is commonly found in the
steering mechanism of cars or otherwheel ed, steered vehicles. This arrangement provides a lessermechanical advantage than other mechanisms such asrecirculating ball , but much less backlash and greaterfeedback , or steering "feel". The use of a variable rack was invented byArthur 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.
External links
* [http://www.brockeng.com/mechanism/RackNPinion.htm Another animation] of the rack and pinion mechanism.
References
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