Steam hammer

A machine hammer, depending on the version also known as monkey, steam hammer, hammer spring or pneumatic hammer, is a forming machine used for forging, rarely also bustle.

It is characteristic of the mechanized forging hammer that the deformation tool as opposed to the rather slow motion in a press at high speed gives the deformation energy to the workpiece. The tool to deliver energy to the workpiece is referred to as Hammerbär. While impact hammers with drive via hydro ( water wheel ) were already in the Late Middle Ages in use, the first steam hammers during the industrial revolution in the years 1842 and 1843 in England outgoing by James Nasmyth and in France by François Bourdon verwirklicht.Zum 19th century, was the spring hammer and a little later developed air hammers, which are now in their more advanced form and robust construction next to the presses craft (eg blacksmiths ) and industrially used for forging.

Types of mechanical forging hammers

Basically, the following forms are distinguished:

Monkey

In this type of hammer, the bear is only as a result of acting on his weight at a speed of impact on the work of around 5-8 m / s speeds.

The lifting of the Hammerbärs to the starting position can be done in various ways.

Even before the industrial revolution Hammers in use, in which the Hammerbär is attached to a pivot shaft and provided with handle and bear about the rotational axis of the pin as a lever to move up and down. The drive is provided, often by water power, by means of a rotating drive shaft is provided with thumb (thumb shaft). Their thumb grasp handle or bear temporarily lift them up and then released, so that the bear accelerated by its weight strikes the workpiece. Depending on the attack position of the thumb is called the forehead Hammer ( attack on the bear itself ), breast Hammer ( attack between bears and pivots) or tail Hammer ( attack on an extension of the stem on the side opposite the bear side of the pivot ).

In a more purposeful design of the bear is done in the vertical, that in contrast to the stem hammering regardless of the height of the workpiece is always parallel to the Unterbär, the anvil, the workpiece is true (so-called vertical hammer ). The bear is raised in these types hammer by an electric motor, a belt transmission or by steam, compressed air or hydraulic fluid to acting piston. Regarding the latter, during the process of the case bears the print medium can escape as quickly as possible and without interference from the flask to avoid by throttling losses. This model of a machine hammer is also referred to as a real monkey. The impact energy is calculated according to the following formula:, where m = mass of the bear; H = height of fall. Here is to be noted however, that the following applies: where g represents the gravitational acceleration. Hammers have a working capacity of 1.5 kNm to 40 kNm. The Bärmasse moves between 100 and 2000 kg.

Upper steam hammer

At the top of the steam hammer Hammerbär is in addition to the acting force of gravity accelerated by steam or compressed air via a directly connected to the bear via a piston rod piston. This results in a larger capacity of the forming machine, however, a higher energy consumption. Steam hammers of this type are also referred to as double-acting.

Acting hammer

In contrast to the simple case hammer and upper steam hammer a gas cushion above the bear is compressed when lifting the Bears a top pressure hammer. The return movement of the bear is done regularly in this case by a hydraulic cylinder. The gas cushion located above the hammer stores energy and releases it during the downward movement of the piston. Thus, there also acts in addition to the acceleration by the weight of a further, caused by the gas pressure force. This kind of monkey is also referred to as an ideal monkey. The impact energy can be calculated by the following formula:, wherein A denotes the area of ​​the piston, which presses against the gas cushion and p prevailing in the gas cushion pressure. When acting hammer work capacity are between 10 and 250 kNm. The Bärmasse is between 15 and 10,000 kg. See also air hammer.

Retaliation Hammer

Unlike the other types hammer while facing demolition hammer is the anvil, so the lower Bear, not securely mounted. The anvil moves rather upward while the upper ram moves down. For this purpose, a coupling of the two bears is necessary. This coupling can take place via two principles. It can be done via a mechanical coupling a compound of two bears by metal straps or a hydraulic coupling hydraulic cylinders. When counter-strike hammer the mass of the lower Bear must be much greater than the mass of the upper Bear. Nevertheless, to achieve a balance of forces, but the lower Bear moves much more slowly than the upper Bear. With counter -blow hammers working capacity 63-1000 kNm can be realized. The Bärmassen move 10000-205000 kg. Compared with other types arise while facing demolition hammer has specific advantages and disadvantages. The largest counter-blow hammer in the world ( Ladish ) has a working capacity of 1,250 KJ, the Müller Weingarten is currently building an even larger 1400 KJ (about 54,000 tons of force ).

Counter-strike hammers require less around 35% building mass as opposed to other types of Hammers with the same working capacity. In operation, they produce less vibration and strain so that the hammer foundation or the overall structure of the work site less. Due to the much higher mass of Unterbärs compared to the upper ram is in case of failure of the hammer the work " automatically " re-enabled. However, a disadvantage is the more elaborate construction and associated higher costs.

Application areas of machine hammering

Hammers are used both in series production, for example when forging of crankshafts as well as in the manufacture of individual parts in open die forging workpieces of all sizes. Occasionally, one deployed for the embossing.

Components of hammers

  • Foundation
  • Frame
  • Guide columns
  • Anvil
  • Bear
  • Height of fall (no substantive existent element )
  • Saddle ( at the nut and the saddle )

Advantages of hammers

  • High impact velocity
  • Low Druckberührzeit
  • Low investment costs
  • Overload Protection
  • High flexibility

Disadvantages of historical hammering

( neglecting largely in modern hammering through good insulation)

  • High foundation loading
  • Strong vibrations

Alternative meaning

Linguistically, the term steam hammer is also used metaphorically but insensitive for something Strong.

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