Drill deck bushing
US4943172A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 30, 1989 |
| Grant date | Jul 24, 1990 |
| Priority date | — |
| Expiry date | Mar 30, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B19/24
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A shock absorbing roller deck bushing for rotary blast hole drills has a steel inner liner with a cylindrical axial bore for receiving a drill string. The liner is rotatably disposed within an outer shell mounted in the drill deck. A split retainer plate is attached to the outer shell and has an inwardly projecting flange around its inner periphery which is captured between a pair of radially outwardly projecting flanges around the outer periphery of the liner. The flanges permit limited lateral movement of the liner with respect to the outer shell, but prevent the liner from being removed axially from the shell. A plurality of shock absorbing cushion roller assemblies are mounted vertically in slotted cages between the liner and shell. The roller assemblies each include a shaft surrounded by a sleeve within a cushion coating bonded to the sleeve, with thrust washers between the ends of the sleeves and the cages. The roller assemblies are free to turn about their shafts and rotate with the liner, and to move radially of the deck bushing to a limited extent, when impacted by the liner. The roller assemblies absorb and dampen impact loads imparted to the liner by the drill pipe.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.