Differential fundamentals .

Differential fundamentals .

1- Transmission shaft ; 2 - Crown wheel ; 3- Driving pinion ; 4- Shaft bearing ; H,H Sun gears ; W,W half shafts ; T , Protective casing ; F , Differential hub

Until the time of Mancock, the rays of the wheels of the vehicles were hammered within the central wood bucket, as still it could be seen in the ordinary cars in the '30s. Hancock found that the wheels thus assembled could not resist the displacements of the axis without braking the rays ; therefore, he made the inner ends of rays of their wheels with wedge form, in such a way that they fit each other by the ends perfectly, and he connected them between two iron discs, one of which had the bucket that maintained the axis. One of them had a pair of salient jambs that fit with another corresponding pair, subject to the axis, and that turned with it. This adjustment gave a slight flexibility to the connection between the wheel and the axis. Practically, all the wood wheels of automobiles around 1920's were made this way.

Another important improvement was the gear of compensation, or " differential ", used for the first time by F. Hill, but invented by Richard Roberts, used in a vehicle to distribute power from the car transmission shaft to a pair of left-right wheels , while allowing wheels to rotate at different speeds.

One may notice that when a vehicle follows a curve, the wheel of the outer part must rotate faster than the one than goes in the internal part of the curve. If the two wheels are solidly fit to the axis, it must produce certain sliding between the wheels and the land, and if the vehicle moves at great speed, specially by a humid surface, this action is not only disagreeable for the occupants, but excessively dangerous. In many of the primitive vehicles of this class, the wheels worked independently or they were connected with the axis by means of staples that could be tightened or become loose voluntarily.

Roberts' invention , which has gotten to be indispensable in the construction of automobiles, has been perfected until producing the modern differential gear, in which the shaft consists of two parts, each one of having a pinion or sun gear, H, and the ordinary wheel, W. A tube, T, is strongly bound to the body of the machine, and does not rotate . The armor, F, rotates by means of the motor, and the wheels can move independently when they march following a course of different length.

The construction of many of these primitive steam moved vehicles was excellent, as much in theory as in the execution of the work, and some of the results obtained with them are worthy to notice like excellent facts of those first times. It is doubtful, nevertheless, that if any other great development had been made following those same lines, without several other improvements that were needed previously, the modern automobile had been able to develop definitively. Of these improvements, the most important has been the gasoline motor , and of secondary importance the tire and the bearing of balls and roller, that have contributed in no small degree to the great success of the vehicle. The bearing of ball and the tire were perfected in the construction of bicycles.

STEAM BUS OF HANCOCK (1839)

Although the promoters of steam cars proved that these ones supposed an economic improvement for the public; that the land used to feed a horse could be used to feed eight people, and that there were two million horses in the United Kingdom, many laws were approved restricting the use of the vehicles moved by steam, and imposing them the highest taxes .

Several of the promoters of the new vehicles were discouraged, and others dedicated their attention to the development of the steam railroads , whose history is described in other pages. Nevertheless, the interest in the steam vehicles as a means to transport passengers by the roads never died completely, and resurged from time to time in the following years. But, in general the application of the steam to road locomotives had been confined to machines of high traction, for road rollers and other similar apparatuses. The remarkable success of the railroad and the fast subsequent development of the iron routes had influenced in a great degree, without any doubt , to contain the development of the steam vehicles by road . We cannot assure, nevertheless, that if although these difficulties had not existed, the steam vehicles could had been a complete success , but , anyway, we owe to the precursors of these works very remarkable inventions that still apply to the construction of the modern automobiles.

STEAM CARRIAGE "ERA" OF HANCOCK (1834)

The problem of the locomotion

The problem of the locomotion by automobile vehicles seemed to be definitively in the way of being solved when the inventors and promoters of these machines found the opposition that appears almost always when new and radical improvements arises. The owners of the roads and the people who used these roads such as coachmen, farmers, proprietors of cars and diligences, all were united in strong opposition against the new vehicles. They said that these were excessively dangerous, that scared the cavalries; others, that spoiled the roads. The interested parts in the services of diligences and related services were opposed, of course, because if the new vehicles were successful, their businesses would go to ruin. One of the engineers in charge to make work these new steam cars wrote: "we are surrounded by harmed people: agriculturists, proprietors of diligences, coachmen , foremen, and others, direct or indirectly related to them, and all of them, helped by the old ladies of Cheltenham, I assure you that they offer a formidable opposition to all innovation ".

STEAM VEHICLE OF GURNEY ( 1822 ) .

Hancock invented an ingenious boiler that could resist high pressures, and that was very solid and manageable. In 1834, from August to November, Hancock put to work his two steam vehicles , called "the Era" and "the Autopsy" between London and Paddington, reaching to transfer altogether near 4,000 passengers and marching at the speed of 32 kilometers per hour. Alexander Gordon, who wrote in 1832, mentioned boilers for road locomotives , which he said they worked at high pressures of up to 200 pounds by square inch, and machines which gave a power of 30 horsepower, constructed for this service. Also he describes coarse condensers, to condense the steam that had been used in the machine of the road locomotives , of such a way that it could return to the boiler, anticipating therefore the more advanced type of machines of the following times. The coke was almost the exclusively used fuel.

STEAM VEHICLE OF TREVITHICK (1802)

Meanwhile in the United States of America, it was Oliver Evans who in 1804 constructed a so called "Orukutor Amphibolis" vehicle, with which he traveled himself by earth and water. All these attempts were more or less lucky tests; but in 1829, W. H. James constructed a car-automobile, that marched at the speed of 2,5 kilometers per hour, transporting passengers. In 1822, sir Golsdsworthy Gurney began to assemble steam vehicles , remarkable successfully. One of his cars appears in the attached figures, and it can be noticed that the boiler that was fixed in the back part of the machine was constructed of tubes, it is to say, that used an idea that later would have a great development. But perhaps, the one who achieved better success among the first constructors of steam vehicles was Walter Hancock, of Stratford (London).

SECOND STEAM WAGON OF CUGNOT (1770)

The invention of the steam engine, towards the end of the XVII century, relived the speculations on the possibilities of flying and of giving propulsion to vehicles, setting out many interesting and peculiar suggestions about the resolution of these problems. An English man, called Francisco Moore, invented a vehicle automobile, in 1769, and he was so sure about his good success, that him and many of his friends sold their horses. But Watt was not so enthusiastic about the use of the steam engine for the vehicles, and it seems that he discouraged to those wanted to solve this problem. In this period of speculation and experiment, the first steam locomotive was born in 1769 which got to transport travelers. It was invented by a French, Nicholas Cugnot .

In his first race took four people, at the speed of 3.62 kilometers per hour. Cugnot was commissioned immediately by the French Government to construct a more perfected and more powerful machine, than could drag cannons . This second machine is still conserved and it is, without doubt, the most interesting and venerable machine in the history of the steam locomotion . In England, William Murdock, one of Watt's assistants , invented a small steam locomotive for roads , in 1774, of which he said that it marched at the speed of 10 to 13 kilometers per hour; and another English man, Trevithick, who later became famous for constructing the first locomotive that marched on tracks, invented the first steam vehicle , in 1802.

History of the automobile, the first steam machines that replaced the horse vehicles .

The adventurous spirits in all the times have ardently wished to fly through the air, like the birds, to cross the earth and to furrow the seas, at great speed and with perfect freedom of movements. Mythology and primitive literature abound in stories and speculations with respect to such aspirations, but until the invention of the steam engine, the most the man could do was to take advantage of the winds to move his boats and to use the animals for the fast transport by the earth. The invention of the steam engine and the gas motor in the past altered all this and has made the airplane and marine navigation possible, and to suppress the land distances in a way that almost justifies the old mythological superstitions. It seems that the period of modern speculation about this problem began towards the XIII century. Roger Bacon, an English Francisca monk, who lived in that time of ignorance about mechanical questions, wrote, nevertheless, in one of its treatises : "We will get to be able to construct machines with which we will be able to impel great boats with higher speeds than all a trimming of rowers, and with which only a pilot who governs the boat will be needed; we will impel vehicles with incredible speeds, without the aid of any animal and we will construct machines that, by means of wings, will allow us to fly in the air, like birds " .









STEAM CAR DEVISED BY SIR ISAAC NEWTON


Everything indicated in this outstanding prophecy written in a time in which none of necessary means for its fulfillment was known nor were signals that it would happen has gotten to be a reality, and would be interesting to know the foundations on which the philosopher based his predictions.
Bacon did not make practical indication about how he hoped that those things would happen; but, in 1680, sir Isaac Newton suggested the idea of a vehicle automobile as it is indicated in the attached figure. It consisted of a spherical steam generator, B, under which it was located a small furnace, D, and all parts mounted on a vehicle with four wheels.

A long slightly conical horizontal tube protruded in the generator in opposite direction of the advance of the vehicle. The steam produced in the generator, B, by the action of the fire of small furnace D, was exhausted by the conical tube, C, at great speed, with which it reacted against the air, causing that the vehicle march forwards. The valve, F, that allowed the exit of the steam by the tube, was under the action of the coachman, by means of the handle, No data exists to demonstrate that Newton got to construct such machine; but the idea, although imperfect is practicable.