Pneumatic drill
US4957171A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1989 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Apr 24, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25D17/265
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A pneumatic rock drill which has a pneumatic percussion unit with a piston which slidably engages the cylinder in which it reciprocates. Preferably clearances of less than less than about 0.00125 inches per inch of piston diameter and greater than about 0.00075 inches where clearances are diameter are maintained to assure a fluid film between the piston and the cylinder wall. The clearances are based on diameters. The piston of the pneumatic drill has at least one stem section which slidably engages a distributor. The rock drill has a pneumatic motor connected to the percussion unit and engages a distributor of the percussion unit. An air motor gear in the pneumatic motor is rotatably mounted on the distributor. The exhaust is employed to lubricate the bearings and gearing which turn the striker bar.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.