Jackhammer chisel damper

Abstract

This paper will present the performance of a rugged Coulomb Friction damper for a Jackhammer chisel. The predominant source of high intensity airborne noise from a pneumatically muffled jackhammer is the ringing resulting from impacting the undamped chisel, which radiates airborne sound from the impacts of the hammer exciting the transverse bending modes. A simulated steel chisel moil point was constructed with geometric properties similar to a jackhammer chisel and designed so as to survive the severe acceleration impacts from the reciprocating hammer. Anechoic tests of the chisel and it damped equivalent indicate that the sound pressure level for the undamped chisel due to longitudinal impact was 86.8 dB linear (re to 20 Pa) with the strongest ring tone at 1.6 kHz and harmonics; the sound pressure level for the damped chisel with identical axial impacts was reduced by 13 dB to 73.5 dB with severe reduction of chisel ring.