| 摘要 |
Boring apparatus having a plurality of hole-enlarging assemblies comprising shaft-mounted working members. In a convergent arrangement of the axes of the working members the assemblies are completed by insertion of the elongated shafts via a hollow space in the bottom connector, through passages in the frame. The upper ends of the shafts are shown held in holes in the frame, and the exterior upper and lower surfaces of the frame are shown as surfaces of revolution, free of wear points. The passages are shown to form cut-outs in the thread of the connector in the first preferred embodiment. In other embodiments the passages are formed through an extension of the frame preceding the connector, and a two-part connector assembly is provided, the passage entering a hollow space provided by the outer part. Also shown, in a boring apparatus, are self-contained lubrication systems in the shafts of each of a multiplicity of rock boring assemblies, with lubricant pressurized by the flushing fluid, as by fluid passing through the shaft, and lubrication fill points at the ends of the shafts, preferably accessible through the hollow space of the bottom connector. |
