PLA

304

PLA

depressed at pleasure, by means of a greater or less quantityof the said fluid being confined between the end of the shaftand the bottom of the step. 6. The materials to be cutmust be firmly fixed on a frame, similar to those in sawing-mills, on which the timber is carried to the saws. Theseframes must be moved in a steady progressive manner as thecutter frame turns round, either by the same power whichmoves the latter, or otherwise, as may be found to answerbest in practice. 7. The motion of the cutter frames mustbe under the control of a regulator, so that the velocity ofthe tool, in passing over the work, may be made quicker orslower, ns such work may respectively require, to cause thecutter to act properly to the best advantage.” For this pur-pose, Mr. Bramah proposes to use what he calls an universalregulator of velocity, and which he describes as follows :“ T take any number of cog-wheels, of different diameters,with teeth that will exactly fit each other through thewhole; suppose ten, or any other number, but, for anexample, say ten, the smallest of which shall not exceed oneinch in diameter, and the largest suppose ten inches in dia-meter, and all the rest to mount by regular gradations intheir diameters, from one to ten. I fix these ten wheels,fast and immovable, on an axis perfectly true, so as toform a cone of wheels ; I then take ten other wheels,exactly the same in all respects as the former, and fix themon another axis, also perfectly true, and the wheels in per-fect gradation also ; but these latter wheels I do not fix faston their axes, like the former, but leave them all loose, soas to turn on the said axes, contrary to the former, whichare all fixed. AH these latter wheels I have the powerof locking, by a pin or otherwise, so that I can, at dis-cretion, lock or unite any single wheel at pleasure to theaxis. I then place the two axes parallel to each other,with the wheels which form the two cones, as above des-cribed, in reverse position, so that the large wheel at one endof the cone may lock its teeth into the smallest one inthe cone opposite, and likewise vice versd. Then supposethe axis, on which the wheels are permanently fixed, tobe turned about, all the wheels on the other axis will becarried round with velocities correspondent to their dia-meters and those of the former, but their axis will notmove. Then lock the largest wheel on the loose axis, and,by turning about the fastened axis, as before, it must taketen revolutions, while the opposite wheel performs butone ; then by unlocking the largest wheel, and locking thesmallest one at the contrary end of the cone in its stead,and turning as before, the fastened axis will then turnthe opposite ten times, while itself only revolves once.Thus the axes or shafts of these cones, or conical com-binations of wheels, may turn each other reciprocally, asone to ten, and ten to one, which collectively produces achange in velocity, under a uniform action of t\\o primummobile, as ten to a hundred ; for when the small wheel onthe loose axis is locked, and the fast one makes ten revo-lutions, the former will make one hundred; and by addingto the number of those wheels and extending the cones,which may be done ad infinitum, velocities may be likewiseinfinitely varied by this simple contrivance : A may turn bwith a speed equal to thousands or millions of times its ownmotion ; and by changing a pin and locking a differentwheel, as above described, b will turn A in the same pro-portion, and their power will be transferred to each, inproportion as their velocities, reciprocally. Here is auniversal regulator at once for both power and velocity.In some instances I produce a like effect, by the same neces-sary number of wheels made to correspond in conical order,but, instead of being all constantly mounted on the axe 3

or shafts, aschanged from

above described, they willone axis to the other, in

recipro 0 ®:^ to

unit,,, single. jis-match according to the speed or power wanted, J® jj r e3'the former instance. This method will have, in * (li epects, the same effect, but not so convenient as w®wheels are ail fixed.” . e M

In 1803, Mr. Bevans obtained a patent for a " iaC ,o*planing, (or sticking, as the joiners term it,) all ^ fl smouldings or rebates, and ploughing grooves, as ^

does

tio® 3

forming flat surfaces of small breadth, which itvery little labour: in this machine, the opera- ,performed by the planes commonly used for similar f* ,0with only such alterations as are necessary to adapt ^ ^,jtlithe machinery by which they are put in

motif 11 ^ be

mechanical power instead of human labour; they a nU m'> er ’used either singly, or combined together in any on c®>according to the width of the boards to be worked * ^ atand the nature of the work to be done, so as to piano ^one operation, such moulding as joiners work ®P> / t ],jsseveral planes successively for the different part 3 > g x jnj?

of

effected by a kind of frame, or box, which admit 3any number of planes in it, side by side, and at a®y^

1 i is

n ce

fit®

asunder, to form the compound moulding requh® u ; g ^ad®work is fixed fast on a bench, and the box of pla ne nI1 ecti”^to pass over it, in the direction of its length, by a ®° e co®'rod communicating at one end with the box or c idr)® r ?taining the planes, and, at the other end, withcapable of affording a reciprocating motion. „,iist ® '

This machinery consists of a crank, whose rad> n iU 3nearly half the length of the required stroke, ^ |,y tl> ebe regulated accordingly : this regulation is e ® eC (r0 iig b°*jarm of the crank passing through a mortise in a 3 re quh efixed on an axis, and sliding in the said box to anylength, where it must be fixed by strong scre '' a ’ n i,being turned by manual exertion, by horses, 3 ffU [ tt tedor any other power, and having its motion toa fly-wheel. . w ith

The planes are loaded, to keep them in contac^ si®^work, by a long beam of wood, set up on end u Pjj V ;ded 111 0of the box, and connected therewith by iCmed tp an letwo cheeks, winch, at the lower sides, aie ^ oim . n the 3fl . ^

. to

of a circle, and united to the box by chains, 1 |J ecte d

rm®

manner as the beams of steam-engines are jgtheir piston-rods. The upper part of the b® a fri®pass always through one point, by sliding k et \ vot8 , p® r .-wheels, or otherwise, in a tube hung on two P 1 jjeig ^dicularly over the centre of the work, an< ^. a 0 f the stf ° e o-as may be most convenient for the length before ^required : the connecting-rod, from the era® ioW® r 6 9(tioned, is jointed to the upright beam, neai 0 f pt® og pand by this means the motion is given t0 1,1 2 it, i® ,the chains and arches at the bottom ali 0 ^* 11 ^ Jjde { b e 0 fftions, to preserve the plane horizontal. 1 bear th eI ?. e j jof planes in a rectilinear motion, and also .j, red 1 " •

TrrlirtM v\ 1 av\L linn L a/ivi *«n /1 11/10/^

conn

tio®'

,e®'

in

when the plank has been reduced to the n£ jjcol ar £ ue ,fences are used, which are irons sliding - n g atubes or sockets, in the box or frame, and c ^ str ok®> 1or ruler, fixed in the direction of the requir e (l ,pa,)

frame supporting the bench. , Q t eekt e r e o®

PLANISPHERE,(from Latin, planus, *** there® ' Q (

a projection of the sphere, and the several gen se, ®^| fii®a plane ; as upon paper, or the like.^ _ I® exln^’Jf

are

cai

the heavens and the earth, in whichmeridians, and other circles of the spheie,spheres. See Projection. , «, be

In all planispheres, the eye is suppo 3 re f el -ri®Sviewing all the circles of the sphere, » nl

lied P

la® 1 '

a P 0 ’

th®® 1

inb

t®