VIBRATION-SAFE PNEUMATIC PERCUSSIVE TOOL

摘要

The invention relates to percussive tools, more specifically to hand-held pneumatic hammers. The hammer comprises a metal barrel situated in the fore part of a tool housing for securing the shank of a replaceable instrument, the dimensions of the barrel corresponding to the dimensions of the shank. The housing is made up of two cylinders of different diameters, which are coaxially arranged one inside the other with no rigid kinematic connection therebetween so that an annular chamber is formed between the cylinders, said chamber being provided with crosspieces that not only act as reinforcing ribs, but also give rise to longitudinal channels which serve as communication channels and additional receivers for the impact stroke chamber and the recoil stroke chamber. The two cylinders and the crosspieces are made of an impact-resistant polymer-elastomer. In addition to a parabolic concentrating head, the coil-type striker has a spherical protuberance in its fore and rear parts respectively, the diameters of the protuberances corresponding to the diameter of the cylinder in which the striker is situated, and the middle part of the striker is less in size than the inside diameter of the cylinder so that an annular chamber is formed. A spherical valve made of a polymer is situated in the gap between the conical surfaces of an upper and a lower seat and is hollow inside. The invention provides for increased vibration safety.