Drop forging hammer
Drop forging hammers are machines for the hot forming of metals .
Forging hammers are differentiated according to their basic structure and / or the type of drive.
A blacksmith hammer , the bear of which only moves downwards through the action of gravity, is called a drop hammer . The bear is brought back up by a belt, a board, a chain, steam, compressed air or hydraulics.
Historical drop hammer in the Freibergsdorf hammer with a die for the production of cannon balls
Sling drop hammer
Strap drop hammers have been around from around 1850 to 1860. The first designs were hand-drawn. A man pulled the bear up on a strap. The bear was dropped from the correct height as instructed by the blacksmith.
After the introduction of steam engines, the drive was done via central transmissions. Today most of the still existing belt drop hammers have been converted to single electric drives.
Board drop hammer
A board is attached to the bear with a wedge connection. The bear is raised by the fact that two rotating drive wheels in the hammer head press against the board and move the board together with the bear upwards.
Upper pressure hammer
In pressure hammers, the bear is accelerated by steam, compressed air or hydraulics.
Operated with compressed air: see air hammer
With the counter-blow hammer or impact former, both tools move towards each other through machine power. As a rule, only the upper ram is driven by expanding compressed air or by releasing hydraulic oil. Counterblow hammers can be distinguished by the different connection between upper and lower rams .
Belt-coupled counterblow hammer
The upper ram is designed as a piston at its upper end, which moves downwards after the blow is triggered by expanding compressed air. A set of steel belts is attached to each side of the ram, which pulls the lower ram upwards at a transmission ratio of 1: 1 via pulleys on the side of the machine. In the middle of their path, both bears meet and are able to transfer forming energies of up to approx. 500 kJ via the dies to the material to be formed. After the end of a stroke, the bears move back to their starting position in the upper or lower dead center.
Hydraulically coupled counterblow hammer
The construction and function is essentially the same as that of the belt-coupled counter-blow hammer, except that instead of the steel belt packages and deflection pulleys, a hydraulic coupling takes over this function. The upper ram pushes a piston rod on both sides into a cylinder, which uses a hydraulic system to apply pressure to a larger cylinder directly below the lower ram and lifts the lower ram upwards in the same proportion. To compensate for leaks and set-up work, the system is supplied by its own hydraulic unit. The upper ram can be powered both with compressed air (impact energies from approx. 400 kJ to 1,400 kJ) and with hydraulic oil (impact energies up to approx. 400 kJ).
A counter-blow hammer with horizontally lying bears