Expansion gear

Gear \Gear\ (g[=e]r), n. [OE. gere, ger, AS. gearwe clothing,
   adornment, armor, fr. gearo, gearu, ready, yare; akin to OHG.
   garaw[imac], garw[imac] ornament, dress. See {Yare}, and cf.
   {Garb} dress.]
   1. Clothing; garments; ornaments.
      [1913 Webster]

            Array thyself in thy most gorgeous gear. --Spenser.
      [1913 Webster]

   2. Goods; property; household stuff. --Chaucer.
      [1913 Webster]

            Homely gear and common ware.          --Robynson
                                                  (More's
                                                  Utopia).
      [1913 Webster]

   3. Whatever is prepared for use or wear; manufactured stuff
      or material.
      [1913 Webster]

            Clad in a vesture of unknown gear.    --Spenser.
      [1913 Webster]

   4. The harness of horses or cattle; trapping.
      [1913 Webster]

   5. Warlike accouterments. [Scot.] --Jamieson.
      [1913 Webster]

   6. Manner; custom; behavior. [Obs.] --Chaucer.
      [1913 Webster]

   7. Business matters; affairs; concern. [Obs.]
      [1913 Webster]

            Thus go they both together to their gear. --Spenser.
      [1913 Webster]

   8. (Mech.)
      (a) A toothed wheel, or cogwheel; as, a spur gear, or a
          bevel gear; also, toothed wheels, collectively.
      (b) An apparatus for performing a special function;
          gearing; as, the feed gear of a lathe.
      (c) Engagement of parts with each other; as, in gear; out
          of gear.
          [1913 Webster]

   9. pl. (Naut.) See 1st {Jeer}
      (b) .
          [1913 Webster]

   10. Anything worthless; stuff; nonsense; rubbish. [Obs. or
       Prov. Eng.] --Wright.
       [1913 Webster]

             That servant of his that confessed and uttered this
             gear was an honest man.              --Latimer.
       [1913 Webster]

   {Bever gear}. See {Bevel gear}.

   {Core gear}, a mortise gear, or its skeleton. See {Mortise
      wheel}, under {Mortise}.

   {Expansion gear} (Steam Engine), the arrangement of parts for
      cutting off steam at a certain part of the stroke, so as
      to leave it to act upon the piston expansively; the
      cut-off. See under {Expansion}.

   {Feed gear}. See {Feed motion}, under {Feed}, n.

   {Gear cutter}, a machine or tool for forming the teeth of
      gear wheels by cutting.

   {Gear wheel}, any cogwheel.

   {Running gear}. See under {Running}.

   {To throw in gear} or {To throw out of gear} (Mach.), to
      connect or disconnect (wheelwork or couplings, etc.); to
      put in, or out of, working relation.
      [1913 Webster]
    

Expansion \Ex*pan"sion\, n. [L. expansio: cf. F. expansion.]
   1. The act of expanding or spreading out; the condition of
      being expanded; dilation; enlargement.
      [1913 Webster]

   2. That which is expanded; expanse; extend surface; as, the
      expansion of a sheet or of a lake; the expansion was
      formed of metal.
      [1913 Webster]

            The starred expansion of the skies.   --Beattie.
      [1913 Webster]

   3. Space through which anything is expanded; also, pure
      space.
      [1913 Webster]

            Lost in expansion, void and infinite. --Blackmore.
      [1913 Webster]

   4. (Economics & Commmerce) an increase in the production of
      goods and services over time, and in the volume of
      business transactions, generally associated with an
      increase in employment and an increase in the money
      supply. Opposite of {contraction}.

   Syn: economic expansion. [1913 Webster +PJC]

   5. (Math.) The developed result of an indicated operation;
      as, the expansion of (a + b)^{2} is a^{2} + 2ab + b^{2}.
      [1913 Webster]

   6. (Steam Engine) The operation of steam in a cylinder after
      its communication with the boiler has been cut off, by
      which it continues to exert pressure upon the moving
      piston.
      [1913 Webster]

   7. (Nav. Arch.) The enlargement of the ship mathematically
      from a model or drawing to the full or building size, in
      the process of construction. --Ham. Nav. Encyc.
      [1913 Webster]

   Note: Expansion is also used adjectively, as in expansion
         joint, expansion gear, etc.
         [1913 Webster]

   8. an enlarged or extended version of something, such as a
      writing or discourse; as, the journal article is an
      expansion of the lecture she gave.
      [PJC]

   9. an {expansion joint}. See below. [Colloq. or jargon]
      [PJC]

   {Expansion curve}, a curve the co["o]rdinates of which show
      the relation between the pressure and volume of expanding
      gas or vapor; esp. (Steam engine), that part of an
      indicator diagram which shows the declining pressure of
      the steam as it expands in the cylinder.

   {Expansion gear} (Steam Engine). a cut-off gear. See Illust.
      of {Link motion}.

   {Automatic expansion gear} or {Automatic cut-off}, one that
      is regulated by the governor, and varies the supply of
      steam to the engine with the demand for power.

   {Fixed expansion gear}, or {Fixed cut-off}, one that always
      operates at the same fixed point of the stroke.

   {Expansion joint}, or {Expansion coupling} (Mech. & Engin.),
      a yielding joint or coupling for so uniting parts of a
      machine or structure that expansion, as by heat, is
      prevented from causing injurious strains; as:
      (a) A slide or set of rollers, at the end of bridge truss,
          to support it but allow end play.
      (b) A telescopic joint in a steam pipe, to permit one part
          of the pipe to slide within the other.
      (c) A clamp for holding a locomotive frame to the boiler
          while allowing lengthwise motion.
      (d) a strip of compressible material placed at intervals
          between blocks of poured concrete, as in roads or
          sidewalks.

   {Expansion valve} (Steam Engine), a cut-off valve, to shut
      off steam from the cylinder before the end of each stroke.
      [1913 Webster]