lever

/lev"euhr, lee"veuhr/, n.
1. Mech. a rigid bar that pivots about one point and that is used to move an object at a second point by a force applied at a third. Cf. machine (def. 4b).
2. a means or agency of persuading or of achieving an end: Saying that the chairman of the board likes the plan is just a lever to get us to support it.
3. Horol. the pallet of an escapement.
v.t., v.i.
4. to move with or apply a lever: to lever a rock; to lever mightily and to no avail.
[1250-1300; ME levere, levour for *lever < AF; OF levier, equiv. to lev(er) to lift ( < L levare to lighten, lift, v. deriv. of levis light) + -ier -IER2]

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Simple machine used to amplify physical force.

All early people used the lever in some form, for moving heavy stones or as digging sticks for land cultivation. Balance beams for weighing were probably used in Egypt с 5000 BC; they consist of a bar pivoted at its center with weights on one end balancing the object on the other. As early as 1500 BC people were raising water and lifting soldiers over battlements using the swape or shadoof, a long lever pivoted near one end with a platform or container hanging from the short arm and counterweights attached to the long arm.

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      simple machine used to amplify physical force. All early people used the lever in some form, for moving heavy stones or as digging sticks for land cultivation. The principle of the lever was used in the swape, or shaduf, a long lever pivoted near one end with a platform or water container hanging from the short arm and counterweights attached to the long arm. A man could lift several times his own weight by pulling down on the long arm. This device is said to have been used in Egypt and India for raising water and lifting soldiers over battlements as early as 1500 BC.

      Another interesting lever device, probably used in Egypt about 5000 BC, was a balance beam for weighing, consisting of a bar pivoted at its centre and weights that were hung on one end to balance the object being weighed on the other end.

 The illustration—> shows how a lever, for example, a crowbar that is supported and can turn freely on the fulcrum f, enables a man to create at b a force P that is greater than the force F that he exerts at a. If, for example, the length af is five times bf, the force P is five times F. In the nutcracker, shown at the right, the two bars are connected by a pin joint at the fulcrum f; if af is three times bf, the force P at b is three times the force F exerted by the hands at a.
 

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Universalium. 2010.

Look at other dictionaries:

  • lever — 1. (le vé. La syllabe le prend un accent grave quand la syllabe qui suit est muette : je lève, je lèverai) v. a. 1°   Placer dans une situation plus haute ce qui est étendu, pendant, etc. Levez cela davantage. On leva la poutre en l air. Le… …   Dictionnaire de la Langue Française d'Émile Littré

  • lever — Lever, act. acut. Signifie haulser, et de bas tirer en hault, Erigere, comme, Levez vous, Erige te. Lever la main, pour prester serment, Manum ad iusiurandum attollere. Lever de terre, Ex humo sursum educere, extollere. Les François l esleverent… …   Thresor de la langue françoyse

  • Lever — Le ver (l[=e] v[ e]r or l[e^]v [ e]r; 277), n. [OE. levour, OF. leveor, prop., a lifter, fr. F. lever to raise, L. levare; akin to levis light in weight, E. levity, and perh. to E. light not heavy: cf. F. levier. Cf. {Alleviate}, {Elevate},… …   The Collaborative International Dictionary of English

  • Lever — Freguesia de Portugal …   Wikipedia Español

  • lever — Ⅰ. lever UK US /ˈliːvər/ US  /ˈlevər/ noun [C] ► a bar or handle which moves around a fixed point, so that one end of it can be pushed or pulled in order to control a machine or move a heavy object: »Lower the lever to lock the machine into place …   Financial and business terms

  • Lever — Sn Audienz während der Morgentoilette erw. bildg. (18. Jh.) Entlehnung. Entlehnt aus frz. lever m., einer Substantivierung von frz. lever aufheben, sich aufrichten, aufgehen , dieses aus l. levāre heben, aufrichten, erleichtern , zu l. levis… …   Etymologisches Wörterbuch der deutschen sprache

  • lever — lever; lever·man; lever·aged; lever·age; …   English syllables

  • lever — [lev′ər, lē′vər] n. [OFr leveour < lever, to raise < L levare < levis, light: see LIGHT2] 1. a bar used as a pry 2. a means to an end 3. Mech. a device consisting of a bar turning about a fixed point, the fulcrum, using power or force… …   English World dictionary

  • lever — (n.) c.1300, from O.Fr. levier (Mod.Fr. leveur) a lifter, a lever, agent noun from lever to raise, from L. levare to raise, from levis light in weight, from PIE root *legwh light, having little weight; easy, agile, nimble (Cf. Skt. laghuh quick,… …   Etymology dictionary

  • lever — ► NOUN 1) a rigid bar resting on a pivot, used to move a load with one end when pressure is applied to the other. 2) a projecting arm or handle that is moved to operate a mechanism. ► VERB 1) lift or move with a lever. 2) move with a concerted… …   English terms dictionary

  • Lever — Lev er (l[=e] v[ e]r), a. [Old compar. of leve or lief.] More agreeable; more pleasing. [Obs.] Chaucer. [1913 Webster] {To be lever than}. See {Had as lief}, under {Had}. [1913 Webster] …   The Collaborative International Dictionary of English


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