| 摘要 |
PURPOSE: To improve a sheath strength and a fixing character by setting the inclination of the slope of peripheral rib facing the entrance portion of a sheath to about 30 deg. and providing a metal sheath with play with respect to the other slope. CONSTITUTION: A sheath 4 made of a synthetic material has a screw streak 5 inside, and a peripheral edge fixing rib 7 triangular in section and two longitudinal ribs outside. The sheath 4 is surrounded with a metal sheath 12. No peripheral edge ribs are provided in the upper portion 6 of the sheath 4. The inclination of the slope 8 of the peripheral edge rib facing the entrance surface of the sheath 4 is about 30 deg.. The metal sheath 12 is brought into contact with the slope 8, but it has play with respect to the other slope 9. Thus, a sheath strength and the character of firmly anchoring the device to the concrete are improved.
|
