Escape wheel

“ The escapement we next describe is that most generally used in chronometers. S S, Fig. 99, is the escape wheel which is kept from revolving by the detent D. On the axis of the balance are two discs, R1, R2, placed one under the other. As the balance revolves in the direction of the arrow, the pin P2 will come round and catch against the point of the detent, lifting it and releasing the escape-wheel, which will revolve, and the tooth T will hit against the stud P1, giving the balance an impulse. ”

“ Escapement—The device in a watch or clock which regulates the motion of the train thus distributing the power of the main-spring. It communicates the motive power to the balance or pendulum. Escapements are of three classes: recoil, dead, or dead-beat; and detached.
Escapement, Anchor—The recoil escapement, invented by Hooke, used in most house clocks. A name also applied to one kind of Lever Escapement with an unusually wide impulse pin. The recoil escapement is one in which each tooth of the escape wheel, after it comes to rest, is moved backward by the pallets. ”

“ The right-hand pallet forms no essential part of the escapement, but is simply a safety pallet, designed to catch the wheel in case of accident to the locking-stone during the time that the left-hand pallet is beyond the range of the wheel. The escape wheel carrying the seconds hand thus moves once only in each complete or double vibration of the pendulum, or every two seconds. ”

“ The great leak of power as transmitted by the lever escapement to the balance is to be found in the pallet action, and we shall devote special attention to finding and stopping such leaks.
WHEN POWER IS LOST IN THE LEVER ESCAPEMENT.
If we use a ratchet-tooth escape wheel we must allow at least one and a half degrees drop to free the back of the tooth; but with a club-tooth escape wheel made as can be constructed by proper skill and care, the drop can be cut down to three-quarters of a degree, or one-half of the loss with the ratchet tooth. ”

“ If we wind up the mainspring of the watch it will immediately cause the main wheel to turn, and, of course, that will turn the next wheel, and so on to the escape wheel. When that wheel turns to the right, as it must, it will force back the arm of the pallet which swings on its arbor. In swinging out in this way it must also swing in the other pallet arm, and that movement will bring it directly in front of another wheel tooth, so that the wheel can turn no further. ”

“ But as a turn of the wheel always corresponds to the same distance accomplished, the faster the vehicle travels the more turns will the wheel make in a given time, and the more movements of progression will the style undergo. This solidarity between the movements of the wheel and those of the style is obtained by means of a small eccentric placed on the vane. At each turn there is produced a puff of air which, by a transmitting tube, causes a tooth of the wheel of the apparatus to escape, and the style to advance by a small quantity. ”

“ The lock-chain ground out the wagon tire in one spot. The brake saves that; and it also saves the animal's neck from that bruising and chafing incident to the dead strain that was required when dragging the locked wheel.
There is another difficulty that has been overcome by the wagon-brake. In stopping to lock wheels on the top of a hill, your train get into disorder. In most cases, when trains are moving on the road, there is a space of ten or fifteen feet between the wagons. Each team, then, will naturally close up that space as it comes to the place for halting to lock. ”

“ The air is full of the buoyant freshness of the hills, and one's thoughts turn to pine forests and rushing waters. Over the superb highway where in ancient days stately processions passed to and fro from Spain, our machine glides on with a sweeping, flying motion, until I find myself leaning over and looking for the wings which should project from the centre of each wheel,—winged wheels, surely. ”

“ A very useful form of the dead escapement, which is adopted in many of the best turret clocks, is called the “pin-wheel escapement.” Fig. 10 will sufficiently explain its action and construction. Its advantages are—that it does not require so much accuracy as the other; if a pin gets broken it is easily replaced, whereas in the other the wheel is ruined if the point of a tooth is injured; a wheel of given size will work with more pins than teeth, and therefore a train of less velocity will do, and that sometimes amounts to a saving of one wheel in the train, and a good deal of friction ”

“ Having thoroughly sifted the many varieties at hand, it has been finally determined that the only means known to provide the most regular flow of power consists in intermittently interrupting the procession of the wheel-work, and thereby gaining a periodically uniform movement. Whatever may be the system or kind of escapement employed, the functioning of the mechanism is characterized by the suspension, at regular intervals, of the rotation of the last wheel of the train and in transmitting to a regulator, be it a balance or a pendulum, the power sent into that wheel. ”

“ The wheelers were always the heavyweights, old and trained, and able to hold back the load or their unruly teammates until the whackers could throw on a brake or "rough lock," the last named a log chain fastened at one end to the wagon, thrown through the wheel spokes in such a way as to be between the ground and the wheel on the "near rear hind wheel" of the lead wagon. ”

“ But what I have mentioned was another turn more, so that the wheels were again in statu quo, and the horse not in the least disordered: if it should be unruly, with the help of one pin, you disengage him from the Calesh without any inconvenience. I myself was once overturned, and knew it not, till I looked up, and saw the wheel flat over my head; and, if a man went with his eyes shut, he would imagine himself in the most smooth way, though, at the same time, there were three feet difference in the heights of the ground of each wheel. ”

“ It will easily be understood how, by tightening the free end of the cord, the break is pressed against the wheels. The bent piece of iron shown in fig. 2, by which the bar of the break is kept in its place, may be replaced by a piece of wood, or even by a thong of leather. Every explorer's wagon should be furnished with a break.
A simple break, used in Italy, in some parts of England and probably elsewhere, is shown in fig. 3. A rail is lashed to the body of the cart, both before and behind the wheel, and is made to press against the wheel. ”

“ And in the gravity escapement clocks there is yet another thin bar about half way between the back frame and the bar on which the bushes of the wheels are set the only use of which is to carry the bush of the scape-wheel, which is set behind the fly; the wheel, the fly, and the pallets, or gravity- arms, stand between these two intermediate bars ; and the pallet- arbors are set in a brass cock screwed to the top of the pendulum- cock. The beat-pins should be of brass, not steel, and no oil put to them, or they are sure to stick. The escapement in fig. ”

“ Indeed, to my mind, there must always be the man who will prefer the reins to the driving wheel. And who can blame him for the choice?
Footnotes
[1] “In Europe, sledge is the name applied to a low kind of cart, but in America the word has been abbreviated to sled or changed to sleigh, which in either case involves the idea that a sliding vehicle is meant. In the rural districts, the farmer employs a machine we call a stone-sledge. This is commonly made from a plank, the flat under surface of which is forced along the surface of the ground by ox-power.” The World on Wheels. Ezra N. Stratton. ”

“ A ricketty waggon—not an English hay-cart, but a spidery trap, with high wheels, so called—and a dilapidated buggy were placed at their disposal. Two children and the old nurse remained to follow in the coach, and the advance guard started, after an anxious consultation as to whether the wheel of the buggy could be trusted to revolve the twelve miles without dislocation. ”

“ If there is to be a change of horses, or you are in your own stable yard at the end of the journey, have your reins unbuckled, let the leaders' reins be pulled through your hands by the grooms, then throw down the wheel-reins, one on either side, or, as circumstances of space demand, retain the wheel-reins, and drive your coach where it is to stand by the wheelers alone, after the leaders are out. ”

“ If carriages had always to move along perfectly smooth roads, such as a tramway of wood, iron, or stone, the use of wheels in overcoming friction would be their sole utility, and the height of the wheels would be of small consequence. But as carriages are drawn along roads with loose stones and uneven surfaces, wheels are further useful in mounting over these obstacles, and it is plain that a high wheel does this more easily than a low one. ”

“ Subjected as it is to the influence of the slightest variation in the motive power and of the least jar or shaking, a balance wheel escapement improvided with a regulator containing within itself a regulating force, could not possibly give forth anything else than an unsteady movement. ”

“ There is a singular addition to their vehicles outside the wheels; a piece of wood curved to the shape of the wheel is placed above it, frequently supported by two straight uprights from the end of the axle-tree outside the wheel; this acts as a wing or guard to keep any one from falling out of the vehicle, and also the dress of the passengers from becoming entangled in the wheel. ”

“ He was pleased to find his command over his machine already sensibly increased. He set himself little exercises as he went along and performed them with variable success. There was, for instance, steering in between a couple of stones, say a foot apart, a deed of little difficulty as far as the front wheel is concerned. But the back wheel, not being under the sway of the human eye, is apt to take a vicious jump over the obstacle, which sends a violent concussion all along the spine to the skull, and will even jerk a loosely fastened hat over the eyes, and so lead to much confusion. ”

“ There is a cobweb of wheeled vehicles of all sorts, from a cab to a hybrid construction something between a wheelbarrow and a costermonger’s shallow. There is much bawling and flinging, shoving, hoisting, pulling and dragging of parcels; all the horses’ heads seem to be turned the wrong way; everybody’s off-wheel seems locked in somebody else’s ”

“ On the one hand you had coachbuilders and others filling the newspapers and publishing tracts, some very serious, some extraordinarily mathematical, others merely facetious, to prove that the roads could be preserved only by using very broad wheels—some,179 indeed, advocated rollers, which, as we shall see, were actually tried—and on the other hand you had people filling more columns, and very dull columns some of them were, to show that a low broad wheel was the one thing which no really satisfactory vehicle could possibly possess. ”

“ Will you state more definitely the nature of the injury you have seen in regard to the effect of the horses' feet, in comparison to that of the wheels of Carriages?—First of all they displace at every blow, they tear up, and throw the surface behind them; whereas the wheel only rolls as it goes, and throws some portion on both sides of it, if the road is soft. ”

“ He expatiates on the exquisite order in which wheel rotates within wheel, but not having heard, he cannot be shocked by the grating of each as it turns upon its axis for discord sets the primary wheel in motion, and its jarring is felt through the whole machine. ”

“ It was the very first time that these primitive savages had seen the principle of the wheel applied to locomotion, and it passed their comprehension altogether. With childish delight and an uproar that baffles all description, both men and women almost fought with one another for the honour of pushing the crude little conveyance about. The perambulator was made out of logs, and was a four-wheeled vehicle; the rims of the wheels being cut from a hollow tree. My blacks were also much amazed at the great size of my mountain home ”

“ I shoe my horses with spikes when showing, so that they shall not slip up, and have strong wheels made for my speed wagons, as the strain on unbanked-up turns, is apt to buckle a very light wheel, which is quite safe on turns that are banked-up. ”

“ Round the wheel was coiled an enormous length of a six-inch steel-wire band, and the disengaged end of the band, after passing over a beam, was fastened to the cross-bar above mentioned. On the bridge of the wheel stood an engineer, the arbiter of fates, who is perpetually unwinding victims down from stage to stage of the Inferno, and winding up the redeemed from limbo to limbo. ”

“ Pressing this invention to the ultimate produced a spoked wheel. The Egyptians used a six-spoked chariot wheel thousands of years before Ezekiel's time, and the Greeks and others had four-spoke models. This was quite an invention and in addition to its useful aspects, it produced some rather unusual, even magical side-effects. As every child knows, if you turn your tricycle upside-down and spin the wheel, the spokes seem to vanish. All that can be seen is the rim and the parts of the hub near the center of rotation. No matter what shape the hub actually is, it too looks round like a wheel. ”

“ If the irons at the axis of a coach-wheel are applied to each other, without the interposition of some unctuous matter to keep them from immediate contact, they will become so hot when the carriage runs swiftly along, as to set the wood on fire; and the fore wheels being smallest, and making more revolutions, will be most in danger. ”