PROBLEM TO BE SOLVED: To provide a dental device having a simple structure and being inexpensive.SOLUTION: A liquid supply tube 20 for connecting a water supply unit and a dental handpiece, comprises a water tube 21 for conducting water, and an outer tube 22 for surrounding the water tube 21. In (a) of the figure 4, water is conducted to the water tube 21 and high pressure air whose pressure is higher than that of the conducted water is supplied to a space between the water tube 21 and outer tube 22. At this time, as shown in (b) of the figure 4, due to pressure difference, the water tube 21 shrinks so that its diameter becomes smaller diameter D2. When water conduction is stopped and at the same time, the high pressure air is discharged, pressure difference vanishes and diameter of the water tube 21 becomes original diameter D1. When returning from (b) of the figure 4 to (a) of the figure 4, water is sucked to the water tube 21, as the result, water does not drip from a tip of the dental handpiece.EFFECT: As the effect, by only fitting the outer tube to the water tube, and then fitting a fluid tube and a fluid pressure switch valve to the outer tube, a structure is formed, the structure is extremely simple and inexpensive.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2016,JPO&INPIT【課題】構造が簡単で安価な歯科装置を提供することを課題とする。【解決手段】給水ユニットと歯科用ハンドピースとを結ぶ液体供給管20は、水を通す水管21と、この水管21を囲う外管22で構成する。図4の(a)にて、水管21に通水すると共に水管21と外管22との間に、通水より高圧の空気を供給する。すると、図4の(b)に示すように、圧力差により、水管21が小さな径D2へ縮径される。通水を停止すると同時に、高圧の空気を排出すると、圧力差がなくなり、水管21は元の径D1に戻る。図4の(b)から図4の(a)に戻る際に、水が水管21内へ吸引される。結果、歯科用ハンドピースの先端から水が垂れることはなくなる。【効果】水管に、外管を取付け、この外管に流体管及び流体圧切換弁を取付けるだけで済むため、構造が極めて簡単であり、安価である。【選択図】図4
