| 摘要 |
The device for undercutting a drilled hole in a concrete wall has an end milling cutter which can be driven by means of a portable drill and is mounted with its shank in a pivotable rotary bearing of a bearing part. The bearing part has an annular shoulder, which can be placed against the wall surface in the area of the hole aperture, and also a centring sleeve which projects axially beyond the annular shoulder and can be inserted into the drilled hole. The milling members of the end milling cutter are designed as elongated plates of a diamond-steel sintered mass which, orientated in one axial plane each and projecting radially beyond the shank surface, are welded to one shank end at equal angular distances from one another. To increase the undercutting angle, the plates are set out radially at an angle to the shank axis towards the shank end. The pivotable rotary bearing is designed as a self-aligning ball bearing which is adhesively bonded in place with its outer race in an annular recess, open at the margin, of the bearing part. Furthermore, an annular pocket for accommodating the inner bearing race in the pivoted state is located at the annular-recess base pointing towards the centring sleeve. The cutter shank has several peripheral grooves which are arranged at an axial distance from one another and into which a snap ring can be inserted which forms a collar which projects radially on the shank and can be supported against the inner bearing race. <IMAGE>
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