Hydraulic hammer
The hydraulic hammer or demolition hammer is an excavator attachment for the destruction of components such as stone and concrete or rock, similar to a pneumatic hammer . In contrast to demolition cutters , for example , a hydraulic hammer can only break material and not cut reinforcements.
Structure, functionality and key figures
A hydraulic hammer consists of a hammer mechanism, housing and - as an insert tool - a chisel.
The impact mechanism converts the carrier from the apparatus (excavator) via high-pressure hoses in the form of hydraulic oil pressure and flow done work in kinetic energy and transfers it to the bit. To do this, the oil is used to build up pressure in a reservoir (e.g. a nitrogen reservoir with a membrane), which then suddenly releases its contents onto the percussion piston underneath, thereby setting it in motion. The energy transmitted per individual impact is called the impact energy , the number of individual impacts per unit of time is called the number of impacts .
The chisel conducts when the percussion piston impacts on it, the energy being used in the material to be broken one, depending on its properties Pointed, flat, or stump chisel. The chisel is guided by the chisel bushing ; Holding wedges prevent the chisel from slipping out completely.
In particular, the housing has the task of noise and vibration insulation. For this purpose, it is usually designed to be closed and damped. Its characteristic shape, which is tapered at the bottom, results from the different space requirements of the striking mechanism arranged above and the chisel bushing with the holding devices arranged below.
In addition to the impact energy and the number of blows, the dead weight and the construction height (with or without a chisel) are other important indicators.
Operation and use
To move the hydraulic hammer, to press the material to be broken with the necessary force and to supply it with hydraulic oil, it is attached to a suitable carrier device ( e.g. excavator ), the size of which depends largely on the weight of the hammer.
In order not to damage the retaining wedges and the chisel bushing, the hammer must not be operated when it is empty , i.e. without a surface. The decisive operating parameters during use are the hydraulic pressure and the oil flow to the hydraulic pump on the carrier unit, as well as the oil temperature and the counter pressure on the return oil line.
For example, a Montabert BRH 501 from the 1980s with a mass of over 1 t required around 80 bar pressure with an oil flow of 110–140 40 · min −1 . This resulted in around 1600 J single impact work at a maximum of 400 impacts per minute. A comparable hydraulic hammer nowadays, such as the LST XB 1100 iS , requires 85–130 ℓ · min −1 , but at up to 140 bar, which results in an impact work of 2000 J with up to 1060 impacts per minute. Devices of this size class are mounted on carrier devices with a net weight of 12–22 t.
Large hydraulic hammers are mainly used as a production machine for direct extraction in quarries. Medium and small hydraulic hammers, on the other hand, are mainly used for secondary crushing or demolition of buildings, foundations, trench and road construction.
development
The first hydraulic hammer HM 400 was developed in 1967 by Krupp (today Atlas Copco ) in Essen and was probably the first machine-guided demolition tool. It was based on a patent granted in 1963 for a hydraulic hammer mechanism. This first system, however, could still be improved. The hydraulic hammer concept was therefore only fully accepted when the Montabert (now Ingersoll-Rand ) BRH was brought onto the market in 1969 . The BRH 501 is one of the most widely used hydraulic hammers.
Further milestones in the development of the hydraulic breakers were:
- 1986 Indeco invented the intelligent hammering system - before that, hydraulic hammers hit with constant frequency and constant force. A special control system for detecting the hardness of the material now enabled the force-frequency ratio to be set automatically.
- In 1989, Henze Baumaschinen invented the soundproofed housing, with which the noise level when working with the hydraulic hammer could be reduced by 10–20 dB (A).
- 2007 Presentation of the largest hydraulic hammer in the world (HB 10000) with a service weight of 10 t by Atlas Copco . The hammer is intended for carrier equipment between 85 t and 140 t net weight. It generates a single impact energy of over 16 kJ (AEM) at an impact rate of 380 min −1 .
- 2008 Hydraulic hammer XB5100iS or XB7900iS from LST with a construction height including chisel of 3.5 m (2.7 m without chisel), 18.9 kJ impact energy (not AEM) and an impact rate between 240 min −1 and 550 min −1 .
See also
- Demolition cutter
- Excavator
- List of construction machinery manufacturers
- List of construction machinery and construction equipment
