Method for inserting wood preservatives into wood

Claim 2

Spiral drill, characterized by a sleeve around it, which is connected with the drill such, that it comes to a standstill, while the drill keeps rotating, as soon as the sleeve comes into contact with the surface to be drilled in.

Claim 3

Spiral drill according to claim 1, characterized in that the sleeve (1) has two different inner diameters, the larger diameter in drilling direction, and is locked between a ring (4,6) which is connected at its side which is turned away from the drilling direction with the drill shaft and has a diameter sized such, that the sleeve is supported thereon, and a Seeger-ring (3) is present in the part of the sleeve having the larger diameter, which Seeger-ring is clampingly positioned in a groove about the spiral part of the drill.

Claim 4

Spiral drill according to claim 2, characterized in that the ring, positioned at the side turned away from the drill direction is a Seeger-ring (4), which is clampingly positioned within a groove about the drill shaft.

Claim 5

Spiral drill according to claim 2, characterized in that the sleeve is made of synthetic material and that the side (6) which is turned away from the drill direction is provided with a steel disc (6) which is or is not fixedly connected therewith.

Claim 6

Spiral drill according to claim 2, characterized in that the ring mounted at the side turned away from the drilling direction is a steel ring (6) soldered onto the drill shaft, having a diameter which is substantially equal to the outer diameter of the sleeve.

Claim 7

Spiral drill according to one of the claims 2-5, characterized in that the sleeve can be lenghtened by elongation pieces.

Claim 8

Spiral drill according to claim 6, characterized in that each elongation piece is provided with raised borders, which clampingly fit into the hollow space of the preceding elongation piece or the first mounted sleeve.