Knight's cyclopædia of the industry of all nations, 1851 / [edited by George Dodd].

Date:
[1851]
Catalogue details

Licence: Public Domain Mark

Credit: Knight's cyclopædia of the industry of all nations, 1851 / [edited by George Dodd]. Source: Wellcome Collection.

    978/1000
    1783 WHEELS. WHITE-LEAD MANUPACTURE. 1784 different forms of the same class of machines, frequently also the axle is made to carry a wheel with teeth on its circumference, in order that, by revolving, motion may he communi- cated to machinery : such are the -wind-mills and water-mills which are employed for grind- ing cox*n. Considered as a mechanical aid in locomo- tion, lifting, transference of power, &c., the Avheel and axle act like a lever of the first kind. WHEELS. In machinery, wheels are generally used for transmitting motion, regu- lating velocity, converting one species of mo- tion into another, reducing friction, or equaliz- ing the effect of forces apphed in an intermit- tent or irregular manner. The simplest mode of transmitting motion from one wheel to another is by causing their peripheries to revolve in contact and pressing them together, in order to prevent shpping. Another mode of transmitting rotatory motion more effectually than by simple contact is by the use of endless bands or straps passing over the peripheries of the wheels which are intended to revolve together. Straps or belts are much used in cotton-factories, and other works in which moving-power has to be com- municated to a great number of machines in different parts of a building, and they are pre- ferred to cog-wheels in cases where sudden strains are liable to occur, because of the yielding character of the connection effected by them. Such straps were formerly made of leather; but caoutchouc and gutta percha are now largely used. Sometimes a chain of links is used instead of a band. To convert rotatory motion into rectilineal-, or rectiUnear into rotatory, various foi-ms of the rack and pinion are used. In its simplest form this contrivance is applied in raising sluice-gates, in lifting-jacks, and various other machines in which a fixed pinion or small toothed wheel is made to give motion to a straight toothed bar capable of moving in the direction of its length. A crank is also ap- phed in various ways for convertmg rotatory motion into rectilinear, or rectihnear motion into rotatory. Of the Excentric and other wheels for producing rectihnear or irregular motion from a revolving axis, or for producing uniform rotation from an intermittent force, the varieties are numerous. The escapement - wheels of clocks and wheels furnish types of another important class of wheels for modifying motion; and snail-wheels, pin-wheels, ratchet-wheels, and fusee Avheels, are among the ingenious contri- vances by which the rotatory motion of a wheel and axle jnay he made to set.in motion a train of comphcated machinery, or to regulate and vary motion at pleasm-e. Another class of wheels, called Friction- Wheels are intended to lessen the evils of friction in machinery. Wheels introduced into machinery for the pm-pose of overcoming inertia, or ot rendering uniform and steady a motion derived from an intermittent or variable source, are called Fly- Wheels. Since they owe their effect to their weight, fly-wheels are usually heavy, and as much as possible of then- weight is disposed in the rim, where, owing to the effect of cen- trifugal force, it is of far more value than when near the centre. The steam-engLae, the stamping-press, the common lathe, the coffee- mill, and a variety of other machines exhibit the useful application of a fly-wheel. In roasting-jacks, musical-boxes, the stiiking- apparatus of clocks, and various other contri- vances in which a retai'ding force is required to prevent the moving power of a spi-ing or weight from rimning down too rapidly, wheels with projecting vanes, which encounter sufii- cient resistance fi-om the aii* to moderate their velocity, are used under the name of Flys or Flyers. A small wheel having cyhndiical staves or spindles fixed between two circular boai'ds or plates of metal, in positions parallel to the axis of rotation, is called a lantern wheel: and when a wheel acts with one which is smaller in diameter, whatever be the form of the teeth, the latter is usually called a pinion. T^Tieels having the teeth formed on then- cu-cumfe- rences so as to project from thence in the direction of the radii are caUed spur-wheels: but when the teeth ai-e perpendicular to the plane of the wheel, the latter is called a crotcn or contrate ivheel. If the teeth are cut on the circumference of a wheel in a dh-ection ob- lique to its plane, the wheel is said to be hevilled; and two wheels may have then- teeth so bevilled as to revolve in planes making any angles with one another. WHETSTONE, is a smooth flat stone used for whetting or shai-pening edged instruments by friction. Whetstones, of which a pecuhar kind for shai-pening razors are called Hones, are made of various kinds of hai'd close- grained stone, and ai-e moistened, when in use, with either oil or water. [Grindstones ; TuEKEY Hone.] WHISKEY. [Distillation ; Kectifying ; Spirit Trade.] WPIITE-LEAD MAFUFACTURE. Tliis branch of industry exhibits many interesting featm-es, both on account of the chemical relations which govern it, and tlio mechanical aiTangemeuts adopted. White lead is made from common metallic