| 摘要 |
<p>The present invention relates to a variable diameter type combination hammer, wherein a casing (20), which is a steep pipe, perforated in the inside and press inserted into a hole at the same time. A wedge type of a sliding piece (31) is installed in an outer circumference of the casing (20) of the combination hammer. When perforating, a drill (10) of the combination hammer is pushed out to an outward direction of the radius. When collecting, the drill (10) of the combination hammer is restored to an inward direction of the radius. According to the present invention, a diameter of the combination hammer becomes variable to enable a steel pipe which is a casing to be easily press inserted and simultaneously perforated on the composite ground in vertically and horizontally perforation.</p> |
