| 摘要 |
A ground anchor (10) comprising an anchor shaft (11) and an anchoring screw (13) moulded onto the anchoring shaft adjacent the lower end thereof. The anchoring shaft (11) is of a rectangular cross-section with four side walls (12). The anchoring shaft (11) is configured at its bottom end (15) for ground penetration. The upper end (19) of the anchor shaft (11) is configured to receive torque applied thereto. The anchoring screw (13) comprises a hub (21) and a screw flight (23) on the hub. The anchoring screw (13) is moulded onto the anchor shaft (11), and the hub (21) is keyed to the anchor shaft. The anchoring screw (13) is so constructed that the spiral flight (23) is rigid yet has some resilient flexibility which allows the flight to deflect laterally in the direction of the screw axis. Specifically, the screw flight (23) has sufficient rigidity to allow it to penetrate the ground in which it is intended to be used when torque is applied to the anchor shaft (11). Further, the screw flight (23) has sufficient rigidity in order to retain the ground anchor (10) embedded in the ground when subjected to the normal load conditions for which it is intended, as is the case with conventional ground anchors. The resilient flexibility provides the screw flight (23) with a degree of "springiness", so allowing the screw flight (23) to deflect laterally in the direction of the screw axis when subjected to the loadings to which it is exposed when winding into the ground. With this arrangement, the pitch of the helical screw (25) is permitted to alter during ground embedment as ground pressure increases. |
