| 摘要 |
<p>PURPOSE:To facilitate engage/disengage of engaging boards by forming the jointing section of column side engaging board and pad side engaging board in annular shape while providing projections engagable in circumferential direction on said jointing section. CONSTITUTION:A synthetic resin supporting tube 7 is stopped to the column 2 side from boss plate 3a while an annular rubber engaging board 8 is secured to the tip side of said tube 7. An annular jointing section 9 is formed on the front face of column side engaging board 8 while many engaging projections 10A, 10B of various size are formed on said section 9. While a supporting tube 11 similar with said tube 7 is supported to the ring section 6 side from the boss plate 3a rotatably around the boss section 3b at the ring section 6 side while facing with said tube 7. A pad 30 is stopped to the base end of said tube 11 while an engaging board 12 having similar projection with that of the column side engaging board 8 is secured to the tip.</p> |
