摘要 |
The two curbs (12,14) have top surfaces which slope downwards near the ends, and there are longitudinal undercut slits (21) with short side arms in the tapered end portions (18) of the curbs. The straps (13) holding the ends together are of a shallow M-shape and have downturned ends with sideways projections (37,38) which fit into the undercut slits. |