Pneumatic hammer drill (I)
US7383894B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2006 |
| Grant date | Jun 10, 2008 |
| Priority date | — |
| Expiry date | May 10, 2026 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25D17/08
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A pneumatic hammer drill includes: a pneumatic cylinder having a cylinder rear end fitted in a handle body, an air passage, and a pressure chamber; and an air valve adjacent to the cylinder rear end. The air valve has a front bearing end, a valve orifice interconnecting fluidly the air passage and the pressure chamber, and an opening disposed at the front bearing end in communication with the valve orifice. A piston is disposed slidably in the pressure chamber, and has a piston rear end capable of moving towards or away from the front bearing end. An air trap arrangement is associated with the piston rear end and the front bearing end to trap air between the same and around the opening so as to provide a shock-absorbing air cushion when the piston rear end moves towards the front bearing end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.