| 摘要 |
Along one length edge the beam has a central symmetry axis (1c) with jaws (1f, 1g) on either side and grooves (1d, 1e) in between, this axis passing through a neck section (1c2) separating the two grooves. A round head is supported on top of this neck section. The grooves have a constant width and are congruent with the curved surface of the cylindrical-shaped head. Along the opposite length edge extends a pair of jaws (1h, 1i) which are received by the correspondingly shaped grooves and clamped around the head in the opposite length edge, one of these two jaws (1i) being longer than the other (1h). The groove (1k) in the outside of the shorter jaw has a greater depth than the groove (1l) in the longer jaw. The beam is preferably made from recycled plastic. |
