Axle.
1. (Machinery.) A shaft or rod on which a pulley, drum, or wheel is placed.
Axles in machinery are known as Live axles when communicating power; as Dead or Blind axles when running, but ineffective, temporarily or otherwise.
Hollow axles are tubular, as their name indicates. They become sleeve-axles when the tube is occupied by a rod or tube forming a live or dead axle, or a fixed axis, as the case may be.
2. (Vehicle.) The transverse bar beneath a vehicle, upon whose ends the wheels are placed.
In the carriage-axle the wheels rotate on the axle-spindle, the axle-tree being relatively fixed.
In the car-axle the wheels are fast to the axle, which rotates therewith. The axle has bearings in boxes. See car-axle.
Carriage and wagon axles are made tubular for strength and lightness; tubular axles are made from welded iron pipes, such as are used for water and gas. The ends are drawn to a taper for the spindles, a butting-ring is then welded on, and the end fitted with a plug on which a thread is cut for the nut. Hollow axles are also made by taking two swaged hollow portions and welding them together. See patents of Lewis, 1871, 1872.
A divided axle is one which is bisected at its midlength; the parts being coupled or otherwise, as the case may be.
The claims to antiquity of this highly useful portion of the carriage do not afford much room for enlargement. The cart and the chariot, whatever may be their order of precedence as regards time, afford the earliest specimens. The details of early forms are comprised in the axle-tree, two spindles, and their linch-pins. Skeins, nuts, straps, clips, boxes, bushing, lubricators, and other devices, seem to have been reserved for the moderns. Axles are made of wood or metal; in the former case the spindles for the wheels are strengthened and preserved by metal (see skeins), and the axle-tree itself receives straps and bands, secured by clips and bolts, for the same purpose. Pliny, A. D. 79, recommends ash, oak, and elm for the manufacture of axle-trees. See carriage, chariot, wagon.
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| Compound axle. |
The arms of the compound truss-axle (Fig. 483) are each made in two parts with an intervening oil-space. One of the parts is placed edgewise, vertically, and the other flatwise, horizontally; the two being united by collars, which form butting-rings, and by screw-nuts, which latter also secure the hubs into the axles.
In Fig. 484 each end of the wooden axle-tree has a cast-metal sleeve, on the outer end of which is a polygonally shaped recess, for a finished metallic spindle, whose shank screws into the end of the axle-tree. A collar on the spindle abuts upon the end of the sleeve and holds it in place. A cap screws on the sleeve, and its flange projects into a face-groove on the inner end of the hub. A similar provision on the outer nut also tends to exclude grit from the bearing surfaces.
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| Carriage-axle. |
While most wheels revolve on the spindles of their axles, others are fast to and rotate with their axles; in the latter case bearings are provided for the axle (as in Fig. 485), in which the parts of the divided axle rotate in bearings attached to the axletree. Each portion is received in a long socketpiece, bolted to the axle, and is retained by a set screw, whose inner end passes into an annular groove in the periphery of the axle.
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| Divided axle. |
In one form of divided axle the tongue is pivoted to the front sill-piece of the wagon-frame, coincidently with the pivot of the slotted middle section [199] of the axle-tree, and the tongue is not affected by the contact of the front wheels with obstructions in the road. The middle section of the axle-tree forms a link in which slip the inner ends of the two outer sections, in which the axles of the wheels have their bearings. Each wheel is secured to its portion of the axle, and each section of the axle-tree is secured by hounds to its respective end of an equalizing bar, which oscillates on the tongue as the wheels swerve out of their course or change their parallelism with the hind wheels. The tongue-hounds are hinged to their sections of the axle-tree, so as to allow the required vertical motion to the tongue, which has also a hingeing joint.
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| Drew's carriage-axle. |
Fig. 487 shows a means of securing the wheel to the axle. It is intended for children's carriages, and the fastening is not exposed at the outer end of the hub. A rod is fitted in the spindle of the axle, and provided at its outer end with a button eccentrically attached. The button in certain positions bears upon the outer end of the hub, and the inner end of the rod is secured by a staple and key.
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| Denison's carriage-axle. |
The bent or crank axle is much used in city drays, its purpose being to lower the bed without reducing the size of the wheels. Bringing the floor of the vehicle nearer to the ground obviates lifting the load to any great extent. The bent axle, to enable the bed of the cart or wagon to come near to the ground, while retaining a large wheel, is a common device in England in city and rural vehicles. One form of driving wheel-axles for locomotives is also bent. Baddeley, a contributor to the early volumes of the Mechanic's Magazine, London, advocated their use, and may have been the inventor.
Paterson (England) proposed that carriages should have axles of unequal length, so as to avoid “tracking,” and thus prevent the formation of ruts.
A turning-axle is the fore-axle of a carriage, which turns on the fifth wheel.
A leading-axle is an axle of a locomotive, in front of the driving axle or axles. The term is applied especially to the English engines, which are not supported in front by a four-wheeled truck, as with us.
A trailing-axle is the last axle of the locomotive. In English engines it is under the foot-plate.
A crank-axle is a driving-axle connected to the piston-rods of a locomotive whose cylinders are inside, technically speaking.
A driving-wheel axle, or driring-axle, is the one on which the driving-wheels are keyed. The power is either applied to cranks on the axle, or to wrists on the driving-wheels themselves.
