245) a rack I, fixed to the carriage, caused a pinion H on the gun to revolve.
The crank shaft carries a pinion which gears into a toothed wheel of a coarse pitch, carrying cutters at the ends of the teeth.
The wing of the bird, like that of the insect, is concavo-convex, and more or less twisted upon itself when extended, so that the anterior or thick margin of the pinion presents a different degree of curvature to that of the posterior or thin margin.
In this instance a very slight movement at the root of the pinion, or that end of the lever directed towards the body, 1 is followed by an immense sweep of the extremity of the wing, where its elevating and propelling power is greatest - this arrangement ensuring that the large quantity of air necessary for support and propulsion shall be compressed under the most favourable conditions.
Fixed to the pinion were three cams, for high, low and mean tides.
This small pinion carries a finger, M, which is arranged to catch against the finger, G, when moved up to it.
The sleeve of the pinion which carries M also carries the dial finger, and if the dial is properly graduated its finger will indicate the weight.
For the sake of compactness and convenience of reading the extension of the springs, and consequently the load, is frequently indicated on a dial, by means of a small rack and pinion, which give motion to a finger on the dial-plate, but the regularity and correctness of the indications of the finger will depend upon the condition of the rackwork and upon the friction, and these will vary with the wear of the machine.
The value d/D usually lies between the limits io/i i and 15/16, and, if a greater difference of E from R is required, a further mechanical advantage can be obtained by employing a separate hand-wheel and chain, or by forming the upper sheave with an annular spurwheel gearing with a pinion driven by a hand-wheel and chain, as in the Tangye form of Weston pulley-block.
A spur pinion D, gearing with both wheels, is carried loosely upon an eccentric E forming part of the central pin, so that when this latter is turned by the hand-wheel F and chain G the axis of the pinion describes a circle the diameter of which equals the throw of the eccentric, and a small relative motion of the two sheaves takes place, depending on the number of the teeth of the annular wheels.
The worm-wheel shaft then sometimes carries a spur-pinion gear ing with a spur-wheel on the lifting shaft, whereby a much greater mechanical advantage is obtained with a small loss by friction of the spur gearing.
A web in the focal plane of telescope marks the point in the field at which the bands are to be made to disappear; this is effected by turning the polarizer by means of a rack and pinion worked by an arm from the observer's end of the instrument.
The iris diaphragm i is pushed to the side by the rack and pinion t n.
In cheap stands the rough adjustment was worked by moving the inner tube by hand, but the more convenient rack and pinion is now used almost exclusively.
By using a rack and pinion movement L the supplementary microscope can be adjusted for the images.
The ink-box is made adjustable, being carried by an arm attached to a pillar provided with a rack with which a pinion operated by a milled head screw engages.
Rotation is communi cated by a pinion, turned by the handle c (concealed in the figure), which works in teeth cut on the edge of the flange h.
9) by the tangent screw f, acting on a small toothed wheel clamped to the rod connected with the driving pinion, there was apt to be a torsion of the rod rather than an immediate action.
This ring runs between friction wheels and is provided with teeth on its inner periphery, and these teeth transmit motion to a pinion on a spindle having at its other end another pinion which, through an intermediate wheel, rotates the heliometer tube.
Per second; but, unlike the older machines, in which the cutting is done in a fixed plane, the chain with its motor is made movable, and is fed forward by a rack-and-pinion motion as the cutting advances, so that the cut is limited in breadth (31 to 4 ft.), while its depth may be varied up to the maximum travel (8 ft.) of the cutting frame.
It followed that when the gun was elevated or depressed, the rack caused the pinion to revolve, and the sight was thus raised or lowered to the proper height to fulfil the conditions given above; but, as Colonel Watkin said, owing to want of level of platform and other causes it was not satisfactory.
The rocking-bar is moved by a rack g into which a pinion on a cross-spindle j gears; the cross-spindle is moved by means of a worm-wheel into which a worm on the longitudinal FIG.
A rack-and-pinion railway (opened in 1897) ascends from Llanberis to the summit of the mountain (44 m.).
To the west of Buda extends the hill (1463 ft.) of Svab-Hegy (Schwabenberg), with extensive view and numerous villas; it is ascended by a rack-and-pinion railway.
It follows that the smallest pinion of a set in which pinion the flanks are straight should have twelve teeth.
Rises the Gaisberg (4206 ft.), which is ascended by a rack-and-pinion railway, which starts from Parsch.
The wing in the insect is more flattened than in the bird; and advantage is taken on some occasions of this circumstance, particularly in heavy-bodied, small-winged, quick-flying insects, to reverse the pinion more or less completely during the down and up strokes."
During the up or return stroke, on the other hand, the posterior margin rotates in a direction from below upwards and from before backwards, so that by a similar but reverse screwing motion the pinion attacks the air from beneath.".
" The figure-of-8 action of the wing explains how an insect or bird may fix itself in the air, the backward and forward reciprocating action of the pinion affording support, but no propulsion.
The angles, moreover, made by the wing with the horizon during the down and up strokes are at no two intervals the same, but (and this is a wing of the martin, where the bones of the pinion are short, and in some respects rudimentary, the primary and secondary feathers are greatly developed, and banked up in such a manner that the wing as a whole presents the same curves as those displayed by the insect's wing, or by the wing of the eagle, where the bones, muscles and feathers have attained a maximum development.
The elastic properties of the wing are absolutely essential, when the mechanism and movements of the pinion are taken into account.
Action with an irregular hammer-like movement, the pinion having communicated to it a smart click at the beginning of every down stroke - the up stroke being more uniform.
The toothed segment, C, actuates the pinion, F, which carries the finger, G, and this finger remains fixed in position so long as the person is standing on the platform.
If now a small weight, as a penny, be passed through the slot, H, it falls into the small box, I, and causes the lever, J, to turn; the lever, J, which turns in friction wheels at K, and is counterbalanced at 0, carries a toothed segment, L, which actuates a small pinion on the same axle as F, and is free to turn on that axle by a sleeve.
When a charge of coal is dropped into the hopper, the bell-crank lever receives a violent jerk from the shackle of the flitch-plate, and this jerk by means of suitable mechanical arrangements throws a pinion on the cam shaft into gear with a wheel on a counter shaft From the Notice issued by the Standards Department of the Board of Trade, by permission of the Controller of H.M.
The rotation of the cam shaft continues till the cam has again heaved up the flitch-plate, when the pinion on the cam shaft is thrown out of gear with the wheel on the counter shaft, and the cam remains steady till another charge of coal is dropped into the hopper and the action is renewed.
Since, however, only relatively low powers are now employed, the ordinary rack and pinion movement for focusing suffices, and for the illuminating the object only a mirror below the stage is required when the object is transparent, and a condensing lens above the stage when opaque.
The signal coil is suspended by fibres and is mounted together with a fixed soft iron core on a brass plate affixed to a rack, with which a pinion operated by a milled head screw engages.