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Steam hammer


Steam hammer
Steam hammer dominated in mechanical engineering for 90 years and was one of the most important cars of its time. Its creation and introduction of its significance for the industrial revolution can be compared only with the introduction of mechanized slide lathe, Henry Maudsley implemented at the turn of the XIX century. The important place occupied by the hammer in the chain of production, explained a great value in forging a general process of obtaining products of iron. As already mentioned, the emergence of forging due to the reduction of iron syrodutnym way. Kritsa soft iron extracted from domnitsy, had a loose porous structure. The pores are filled with slag it. To get a high-quality iron and steel for the manufacture of tools, should remove the slag and pores brew. This is precisely achieved by forging. Forging metal could only be heating it up to welding heat: the blows inflicted by the hammer, had to be the most powerful to weld in places bundle really happened and were not formed voids. In addition, the hot metal bounces squeezed the remnants of the slag, which also increased the quality of the iron. Only a well-forged metal is then suited for the production of tools and weapons, and for many centuries they were also manufactured exclusively by forging. Later, in XVIII-XIX centuries, - forged and machine parts.

In ancient times, all the blacksmith work fully fulfilled smith. In the future, there was a division of labor - the most qualified to perform the work continued the blacksmith, and the heavy, low-skilled, - blacksmith, working under his direction. Smith worked with a hammer in the 1-2 kg, and Hammers - sledgehammers, whose weight reached 12 kg. Sledge is placed on a long stick of hard, elastic, neschepyaschihsya wood. "In the scope of" Long stick it possible to hold the hammer with both hands and beat in a circular motion. The division of labor between the blacksmith and the blacksmith opened the possibility to mechanize heavy monotonous beats produced by the latter, and transfer its work mechanism. In the Middle Ages was invented cam hammer driven by a water wheel. The first such hammers were already in the XIII century, and their widespread use relates to the XVI century. At the end of the XVIII century it came into use hammers driven by a steam engine. The patent for the invention of the hammer was in 1784 James Watt.

The connection of the hammer with the machine at first did not change anything in his own design. It was the same tail claw hammer that for four hundred years before the opening of Watt was powered by a water wheel. Moreover, it was possible to see its ancient prototype of a manual without difficulty. Age couple is not changed neither its form nor the principle of action, only to increase the size and weight. But this situation could persist for a long time. In subsequent decades, the development of mechanical engineering, railway construction and, mainly, the construction of the huge ocean liners require machining parts unprecedented size before. Shafts paddle wheels, cranks and other parts of steam engines often reach enormous size. For their manufacture were created giant machines, including powerful steam hammers. However, the design of the cam hammer, which had many shortcomings, not allowed to forge with high quality especially large blank. The strength of the hammer hitting directly dependent on the height of its fall. Meanwhile, with increasing preform size decreased clearance between the striker and the anvil, and thus weakened impact force. This is a big disadvantage, because the strikes proved the weakest, and vice versa, in the processing of large and massive parts - for machining small thickness hammer operated with maximum force that was completely back to production needs. As a result, a massive part time to cool before forging ended. It had to be heated again and translated under the hammer again. It takes a lot of time and effort, but forging quality still leaves much to be desired. Furthermore, since the movement of the hammer was carried out not in a straight line and an arc, you can never be achieved strict parallelism between the hammer and the anvil surface (except in cases where the hammer-forged parts intended for the same thickness).

Such was the state of affairs in the early 40-ies of the XIX century, when there was a steam hammer Nasmyth built on entirely different principles. He immediately became widespread, as answered the most pressing needs of production. The reason for this remarkable invention was filed in the following circumstance. The company "Great Western Company", for which the plant Nasmyth constantly supplying machine tools, has received an order to build a giant ship "Great Britain." The ship was supposed to be a giant crankshaft with 750 mm diameter. As it turned out, to forge a shaft with the help of the then existing hammers it was impossible. Upon learning of the company's difficulties, Nesmith began to think about how to implement such a gigantic forging. First, he proposed to improve the old hammer, but then realized that it is necessary to opt out of the old scheme and create a new device, in which the steam engine and the drummer will be joined into a single mechanism.

One of the main disadvantages of all previous hammers consisted in the fact that the movement of the steam engine to the shock of the hammer passed irrationally. The reciprocating motion of the piston in the cylinder of the machine is first converted into a rotational movement of the cam shaft. Then again I had to convert the rotary motion of the shaft into a reciprocating motion of the hammer. "And was there any benefit in this complex transformation of the movement? Absolutely no, - he wrote later, Nesmith. - On the contrary, this stemmed from only a number of important disadvantages - first of all, lost power. " Well aware of the shortcomings of the old design, Nesmith created a new machine with a freely falling test section, which has been deprived of them. The main parts of his hammer steel cylinder, piston and supporting their bed.

Steam cylinder C was located so that the piston rod out to the side of the anvil cylinder K. C supports two racks About, form a base frame. «Baba» B moved between the uprights in the grooves and carrying the striker, who was interchangeable and was dependent on the nature of the work performed. The steam from the boiler through the pipe P into the chamber, where the moving slide. When the spool is in the bottom position, the steam entered under the piston and raising it, as well as the stock, "a woman" and a striker. If the handle is turned in the opposite direction, the valve stop flow of steam under the piston and opened it to the atmosphere through the main conduit. Then falling parts under its own weight hits the workpiece with force, completely inaccessible to the tail of the cam hammer. The steam pressure was adjusted by reducing the aperture through which it is produced. Thus it was possible to get the hammer to fall faster or slower and thus apply more or less severe blows. Completely blocking the exit of steam, could instantly stop the hammer at any point. How a new Hammer was obedient in management, says this episode. In 1843, the Lords of the Admiralty came to the factory Nasmyth, wanting to explore his invention. Nesmith himself driving the car, which had a weight of falling parts 2, 5 m. To surprise of Lords, he had prepared a kind of focus. On the anvil was set crystal glass of raw egg. Start the machine, Nesmith broken shell eggs without damaging the glass.

The commercial success of the new machine exceeded all expectations. Hammer became a sensation among machine builders. In order to become familiar with its design, the engineers and mechanics came from all over the country. It received a lot of orders, and the steam hammer began his triumphal march first in England and then across the globe. (One of the first orders came from Russia.) This invention Nasmyth brought worldwide fame and reputation of being one of the leading machine builders. Even during his lifetime, in the second half of the XIX century, steam hammers reached colossal proportions. Thus, the hammer "Fritz" was built in 1861 at the Krupp factory. His "baba" weighed 50 tons.

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