Sliding pressure control valve for pneumatic hammer drill
| DWPI Title: Apparatus for controlling e.g. pneumatic percussion drill, has compliant biasing device in non-rest compressed position when ported valve is at point along feed tube, where point along feed tube is closer than another point |
| Abstract: A pneumatic device control apparatus and method comprising a ported valve slidably fitted over a feed tube of the pneumatic device, and using a compliant biasing device to constrain motion of the valve to provide asymmetric timing for extended pressurization of a power chamber and reduced pressurization of a return chamber of the pneumatic device. The pneumatic device can be a pneumatic hammer drill. |
| Use: Apparatus for controlling a pneumatic device e.g. pneumatic percussion drill and rock breaker. |
| Advantage: The apparatus makes timing of air flow to drill chambers asymmetric with respect to power and return stroke of a piston, so that the valve controls the points during the stroke in which the air flow from the feed tube to the power chamber is terminated during the power stroke, thus permitting a termination point that is closer to the piston impact point to improve overall efficiency of the power chamber over a longer extent of the strokes. |
| Novelty: The apparatus has a compliant biasing device operatively connected, constraining motion of a ported valve (12), providing asymmetric timing for extending pressurization of a power chamber and reducing pressurization of a return chamber of a pneumatic device. The biasing device is in a rest position when the ported valve is at a point along a feed tube (24). The biasing device is in a non-rest compressed position when the ported valve is at another point along the feed tube. The latter point along the feed tube is closer to a drill bit than the former point along the feed tube. |
| Filed: 2/3/2009 |
| Application Number: US2009364600A |
| Tech ID: SD 10988.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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