Superposed drilling device
AssigneeIng. Guenter Klemm Bohrtechnik GmbH
InventorGuenther W. Klemm
Life of this patent
Estimating the term…
Abstract
The device comprises a solid drill bit (28) and an annular drill bit (40). Axial impacts are exerted on the solid drill bit (28) which are transmitted onto the annular drill bit (40) through impact transmission surfaces. The annular drill bit (40) is freely axially displaceable within limits. It has rearwardly projecting tongues (43) that engage windows (15) of an outer pipe end piece (12). Thus, the movability of the annular drill bit (40) is ensured without any keyings or the like being necessary, which entail the risk of a clogging with bore material. All movable parts are included in the scavenging so that jamming is avoided.
Claims7
A superposed drilling device comprising a solid drill bit (28) onto which impacts are exerted or transmitted, and an annular drill bit (40) enclosing said solid drill bit (28), which is axially movable relative to said solid drill bit (28), said solid drill bit (28) and said annular drill bit (40) being coupled to each other by impact transmission surfaces (31, 50) that abut against each other and transmit the impacts onto said annular drill bit (40),
- characterized in that
- said annular drill bit (40) has axially projecting tongues (43) that engage windows (15) of an outer pipe end piece (12) in a longitudinally displaceable manner, said outer pipe end piece guiding said annular drill bit.
Dependencies are inferred from the claim text.