DE29516413U1 - Chisel for hydraulic hammer - Google Patents

Description

DESCRIPTION:

"Heissel for hydraulic hammer"

The utility model relates to hardness specifications of hydraulic chisels.

Hydraulic chisels (hereinafter referred to as chisels) are used in hydraulic hammers and are used for crushing rock, concrete and for demolition work.

The chisel is driven into the material to be treated by a rapid series of blows from the hydraulically operated impact piston on the chisel head and results in crushing by disrupting and splitting the material.

The chisel is therefore exposed to high levels of wear in the working area (2) and on the impact head (3). To withstand this stress, the chisel must be very hard.

During use, damage to the chisel surface (4) cannot be avoided. This damage, in conjunction with ^bending stress caused by lateral forces, leads to cracks and the resulting fatigue fracture leading to the failure of the chisel.

In the insertion area (1), the high impact rate in combination with a short relative movement and high surface pressure leads to pitting despite lubrication. This surface disruption leads to cracking and finally to the failure of the chisel. This stress requires low hardness with high toughness.

Attempts are made to meet these contradictory requirements by varying the chisel hardness to suit different operating conditions, by shot-peening the surface and by using steels with a high nickel content.

The application describes a chisel which has a high hardness of 49-52 HRc in the core and on certain surface areas and hardness values of 43-45 HRc on the edge, thus ensuring a low susceptibility to cracking and high fatigue strength under flexural stress.

The requirements for the material used are clearly
lower than before and must be adjusted to the respective diameter
only provide the required core hardness.

Shot blasting can be omitted.

Claims (1)

I I I Il I · · ··» · I UTILITY MODEL REGISTRATION " Chisel for hydraulic hammer " Utility model claim: Hydraulic chisel in the form of a round material, which is provided with a corresponding shape at one end (insertion area-1) for holding in the hammer. The other end (working area-2) has a conical or pyramid tip, a cutting edge by flattening on both sides or a wide cutting edge by widening the round material and flattening on both sides. Characterized in that the chisel has a hardness gradient from the edge (approx. 43-45 HRc.) to the core (approx. 49-52 HRc.).