| 摘要 |
The subject of this patent application is a pneumatic rock drill. It is a ha nd held unit called a "stoper". When in operation, the operator controls the operation by holding an attached handle. The operator also intermittently holds a rubber hose, which is attached to the drill and supplies the air required to operate the drill. Vibrations as high as 36 metres per seconds squared are transmitted to the hands of the operator from both the handle and the hose. Research has identified the injury caused by these vibrations as Raynaud's Phenomenon referred to as hand-arm vibration syndrome (HAVS). In most cases, the injury is compensated. Researchers have attempted to isolate the handle and hose from the body of the drill, which is the primary source of the vibratio n. All efforts have failed. When in operation, the drill is held against the drill steel by a pressurize d piston type permanently attached leg (figure 2), which rests on solid ground or a drilli ng platform upon which the operator stands. Vibrations from the operation are transmitte d through its leg piston to the platform and ultimately through the whole body of the operator. There are four physical factors of primary importance in determining the human response to vibration, namely, the intensity, the frequency, the direction and the duration of the vibration. In the practical evaluation of any vibration of which a physical description can be given in terms of those factors, three main criteria can be distinguished . These are: a) the preservation of working efficiency, b) the preservation of health or safety, c) the preservation of comfort. The recommended limits of exposure are set by the International Organization for Standardization (1986) (ISO5349). The manner in which the requested patent contributes to a, b, and c above is set out in the claims section of this application.</ SDOAB>
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