| 摘要 |
The fastener has a core (1). Extending from opposite sides of the core are a pair of major fins (2) and a pair of minor fins (3). The fins are formed so as to follow a 30 DEG helix. The ends of the fastener are pointed. The material of the fastener is stainless steel, work hardened in its formation. In use, the fastener can be hammered into a 2.5mm pilot bore (11) through a timber (12) and a piece of steel work (13). In the timber, the minor fins have lightly gripped the timber, but the major fins have cut into the timber to cause the fastener to twist on its helix as it is driven in. When the fastener reaches the steel, the minor fins have a diameter to engage and cut into the pilot bore for good grip. |
