Gear ratio

“ Another method of shifting to a lower gear ratio is to leave the throttle open and release the clutch just enough to allow it to slip and the engine to speed up. The gear shift lever should then be moved through neutral directly to the next lower speed position and the clutch engaged. ”

“ Under the latter conditions, viz., with the higher gears in use, the rider's feet revolve the crank axle slower, but the ratio of gearing being about one to two and a half turns of the road wheel on normal or middle, and three to three and a half turns of the road wheel on top gear, the machine moves faster with approximately the same exertion; or to explain it another way, the rider has no need with a high gear in use to exhaust himself with rapid pedalling as he would do if he wished to ride fast with a normal single gear. ”

“ When the central pinion is held stationary the hub is driven at a less speed than the chain-wheel; the gear-ratio is 100 : 76.2.
In the Fagan two-speed gear, shown combined with the Eadie coaster hub in fig. 12, the sun-wheel B can be moved laterally by the striking gear, so as to engage with the chain-wheel centre C, giving normal gear, or with an internally toothed wheel A fixed to the spindle. The chain-wheel centre C carries the annular wheel, and the four planet pinions D are mounted on the driving cone H. Thus the gear gives a reduction of speed, the gear-ratio being 100 : 75. ”

“ As a large gear reduction is thus rendered possible on the back axle, it will readily be understood that the change-speed gear-box may be made considerably smaller than would be necessary for a bevel-driven live axle, where a large gear reduction is not permissible, both on account of its size and because such a gear would be very noisy in its working. ”

“ If gears of exactly the proper size cannot be obtained readily, the position of the intermediate gear may be adjusted to produce a proper meshing of the gears.
Mount the small gear on the end of the armature shaft away from the commutator, so that there will be about 1⁄16-in. clearance between the outside surface and the shoulder at the end of the shaft. Fit it on tightly so that no other means of fastening will be necessary. Mount the large gear on the inside surface of one of the truck wheels, as shown in Figs. ”

“ In order to travel fast over level country, and yet be able to mount hills without undue exertion, we must be able to do what the motorist does—change gear. Two-speed and three-speed gears are now very commonly fitted to cycles. They all work on the same principle, that of the epicyclic train of cog-wheels, the mechanisms being so devised that the hub turns more slowly than, at the same [Pg 443] speed as, or faster than the small chain-wheel, [42] according to the wish of the rider. ”

“ Unfortunately, the great majority weigh between 38 and 40 lbs., and some are much more.
If a tourist wants greater comfort and reliability than can be obtained with such a specification as above he must be prepared to push along about 45 to 50 lbs. Many full tourist machines with heavy spring saddle, gear case, 13⁄4 in. tyres, wide rubber pedals, and three-speed hub, weigh quite as much as 50 lbs. and sometimes more.
Comfort must be sacrificed to some extent to secure lightness, and it is for the individual to decide what he thinks will best suit his or her requirements. ”

“ The engine governor having limited the speed of the 3-ton type to 16 miles per hour, and the speed of the 30-cwt. type to 20 miles per hour, the next step is to secure that, when road conditions require the use of lower gears, the whole of the vehicles in the convoy will need to change gear practically at the same point, and when on lower gears will run practically at the same speeds. ”

“ For the benefit of those of our readers, who have no previous acquaintance with mechanism, we shall merely premise that a gear is a wheel with a toothed circumference, like watch-wheels, or what in ruder mechanism are known as cogged-wheels; and those gears, known as level gears, are such as have the toothing on the circumference not perpendicular to the plane of the diameter, but at an acute angle to it, so that when two gears of a peculiar degree of bevil are set in contact, a horizontal rotatory movement may be communicated to one by a corresponding perpendicular rotation of the other. ”

“ The question of gearing is complicated by the fact that the frame of the car oscillates vertically with respect to the axles. Spur-wheels, worm-gear, friction gear, belts, multiple-band gear, and chain-gear are or have been used. ”

“ With a three-speed gear the low and high gears should be chosen respectively below and above the single gear which suits the rider, the middle gear being about the same as the rider’s usual single gear.
All the variable speed gears at present made consist of toothed wheel mechanism either at the hub or crank-bracket, and nearly all are based on the same epicyclic train of toothed wheels. At one speed there is no relative motion of the toothed wheels, the whole mechanism revolving as one solid piece ”

“ Each cheek has on the side a trail-handle and a manœuvring-ring. In rear of the rear transom is placed an eccentric-roller, having a projection in the middle of it, just large enough to fit in between the rails of the chassis, and guide the trail of the carriage. When this roller is in gear, the weight of the trail rests upon it, while that of the front part of the carriage is thrown upon the front rollers, and the piece is then easily run in and out of battery ”

“ With only two gears where roads or grades are such that the high gear cannot be used, there is nothing to do but drop to the low, —from thirty miles an hour to five or six,—and the engine runs as if it had no load at all. American roads especially demand intermediate gears if best results are to be attained, the conditions change so from mile to mile. ”

“ Gear-case.—The modern roller chain by makers of repute is so durable that the necessity for a gear-case is not so great as when chains were of inferior quality. But if the bicycle is to require the minimum amount of care and attention a gear-case should be fitted. The Sunbeam gear-case is built into the frame and is oil-retaining, and the chain, chain-wheels, free-wheel and two-speed gear are continually lubricated by an oil-bath. A detachable gear-case is not usually oil-retaining, but serves to exclude grit and mud from the chain. ”

“ Hub gears lost favour with motor cyclists on account of the weight of the gear being in the wrong place, and because so many hub gears intended for solo riding were used with side-cars and passengers, and proved unequal to the task of the double work. The modern motor cycle gear is now almost wholly of the countershaft type, and contained in a separate box or case like the change speed of most motor-cars. ”

“ We now have uniformity in height and contour to insure perfect contact between all classes of equipment, and a positively locked knuckle. The design and attachments to car body are prescribed of a strength in excess of the power of locomotives, and in modern friction draft gear the strength reaches 250,000 pounds. ”

“ Nearly all the makers are providing sufficient clearance at the crank axle and rear fork-end, so that a gear-case can be used. Many of the makers have gearcases of their own production, and there are two or three detachable ones on the market which are composed of hard and soft rubber, metal and leather combined. More gearcases will probably be sold this year than ever before in the history of the trade, public attention having been largely called to them by the neatness and desirability of the case as used on the bevel-gear cycles. ”

“ The imported gear cases are clumsy and heavy, and, being made mostly of metal, are apt to be noisy. The 1898 gear cases of American make are made of a combination of rubber, leather and metal, and are light, noiseless and graceful, and most of the leading makes of the chain cycles for the coming season are built with sufficient clearance to take a gear case. ”

“ In shifting to high speed from medium, the engine should be throttled more closely and the shift lever should hesitate again, if one would avoid the thump and jerk commonly felt when the high gear is thrown in. The engaging teeth of gears A and D will stand a sledge-hammer blow, but “constant tapping wears away the hardest rock,” you know, and the best gears made wear and break. Besides there is the jar to engine and car to consider. ”

“ French, British, and Indian Cavalry Divisions were "going through." On the 14th we packed up and were on the move again and bivouacked for the night on the roadside just short of ——, which was our railhead the following day. A sudden move is no light matter! More fortunate than other branches of the Service in the matter of carrying capacity, A.S.C. motor-lorries, when loaded up to their utmost capacity with rations and forage, do not offer as much accommodation for the carrying of kits and mess gear, though, as might at first sight appear. ”

“ On hard roads in a level country high gearing is all well enough, and a high average speed can be maintained, but where the roads are soft or the country rolling, a high gear may mean a very material disadvantage in the long run.
It is of little use to be able to run thirty or forty miles on the level if at every grade or soft spot it is necessary to throw in the hill-climbing gear, thereby reducing the speed to from four to six miles per hour ”

“ The above cut represents a very cheap and simple gear-cutter. Its principal novelty consists in the use of the large gear-wheel instead of the common graduated table. It is extremely simple, and at the same time possesses all the advantages of the old machine. It will be observed that the crank is connected to the large wheel by a set of intermediate gears, every revolution of which is made to correspond with the number of teeth in the wheel to be cut. ”

“ By gripping the endless rope between grip wheels (see 1208) the small wheel can be thrown into gear to grip the rope by a lever, cam or screw.
c. Differential gear may be driven from a shaft by belts or gearing. See Sections 84 and 3.
d. Screw gear. Ditto.
e. Rack gear. Ditto.
f. Worm and wheel gear. Ditto.
g. Friction gear is usually driven as No. 1211.
1211. Where the barrel shaft has a slight horizontal movement, so that, by the lever, it can be forced into gear with the friction pinion to raise the load, or into the brake block to sustain the load or lower it. ”

“ By means of these it is possible to change the gear of the machine so as to have a high gear under favourable conditions and a low gear when mud, wind, or an ascent make travelling difficult. Although chain gearing is used in nearly every machine made, connecting rods, wheels, or bands are fitted instead to some machines. ”

“ No doubt a carriage of one construction will travel easier than of another, with the same weight; and where the mechanical advantage thus gained is greatest, the heaviest weight may be put, with the same number of horses; but in the carriages usually made for the service of artillery, 4 cwt. per horse, beside the weight of the carriage, is the utmost they ought to be allowed to draw.
The French ammunition waggons, which are drawn by 4 horses, are always charged with 1200 pounds only. ”

“ The first provision against the helplessness that must, and the disaster that probably would, follow broken or disconnected steering gear, is sufficient strength in the parts. It should be as direct and simple in arrangement as possible, because least liable to disarrangement and because gear with chains and short rods and connections through springs have so many more points for possible looseness and losses and more to examine and yet be uncertain about. ”

“ Usually no difficulty would be experienced in shifting to a lower gear if the car speed is diminished sufficiently. As a general rule, when shifting to a lower gear the speed of the car should be a little less than when shifting to a higher, between the same relative gears. ”

“ At first sight, it might appear that sand and mud might create a disturbance by edging themselves into these small gears, but the makers maintain that a gear case is unnecessary, because the gears practically clean themselves, in consequence of each gear wheel running in direction opposite to that of its neighbor. ”

“ In the rare cases when actions have taken place, motor trucks have become moving forts, which continue on their way at a rate of twenty or twenty-five miles an hour, while from each one three or four well-protected riflemen keep up a steady fire.
The type of automobile most desirable for army use has become well-defined. The practice in this regard is the same in the French, British, German, Austrian, and Hungarian armies. On a powerful chassis, with an engine of at least 50-horse-power, is mounted a very light body, of the “pony tonneau” type, with room for two men in front and two behind. ”

“ The driving power being transmitted from front sprocket or gear by shaft tube to rear gear or sprocket, all being suitably secured as above stated to frame upon rear fork rotatably supported by ball bearings connected to the frame and forks.
“This does precisely what has always been accounted to be out of the question and confutes both theoretical and practical mechanics. It is a gear that turns the corner by means of square cut teeth that mesh directly instead of by means of bevel teeth, and we call it a face gear. ”

“ But next in its favor, as before said, is that the above advantages are not gained at the cost of added complication of parts or increased cost of machinery, but the reverse, as this gear can be built at a less cost than link gear, varying according to the circumstances, but reaching as high as a saving of 25 per cent., or, if it be compared with a link gear supplemented by the usual special expansion valve and gear as employed on marine engines, then the total saving is fully 50 per cent., and an equally good result is obtained as to the distribution and subsequent treatment of the steam. ”