| 摘要 |
22 DOWEL JOINT SYSTEM FOR CONNECTING WOODEN ELEMENTS A system for fastening a dowel to a wooden element includes a drilling assembly for forming a blind hole in the wooden element which includes a first portion which is cylindrical and a second portion which tapers outwardly in frusto conical shape from the lower end of the first portion. A dowel having initially a cylindrical shape is inserted into the blind hole and the expanded outwardly into the frusto conical portion. The expansion can be carried out by a tapered plug which is forced into the end of the dowel, by a wedge member which is forced into slits in the end of the dowel or by expansion of the dowel itself from an initial compressed position by absorption of moisture from an adhesive. The drilling is effected by a compound drilling assembly which includes a first and second drilling element, the latter being movable axially relative to the former with the axial movement causing the latter to move outwardly along the frusto conical shape to form the second frusto conical portion after the first element drills to the required depth of the hole of the bore.
|
