| 摘要 |
A drill comprising a body means having an axial, generally cylindrical, interior space is provided with a first cylindrical piston axially slidable between a first and a second position within the cylindrical space. The piston is provided with an extension in the form of a second piston, and the first and second piston surround an axially disposed flushing tube, which with the piston defines a first annular oiling space. The flushing tube, the first piston and the body define a second annular oiling space, while the flushing tube, the second piston and the body define an annular pumping zone. A source of lubricating fluid communicates with the pumping zone by means of the body inlet as the first piston is moving towards said first slidable position, and the pumping zone communicates with the second annular oiling space by means of the first annular oiling space as the first piston is moving towards said second slidable position. The first annular oiling space and the inlet are provided with one-way valve. In this manner, the surfaces between the flushing tube and the piston, as well as the surfaces, for example, between a drill neck and a bushing in the second annular oiling space, are effectively lubricated and cooled. |
