Keyhole saw
A tool for creating a wall opening. The tool includes a hole saw; and a centering jig having a center axis, where the centering jig is constructed as a centering ring, into which the hole saw can be pushed at least partly, and in that both the hole saw and the centering ring have on their circumference an opening such that this can be pushed transverse to the center axis completely onto a line.
1. A tool for creating a wall opening, the tool comprising:
a hole saw; and
a centering jig having a center axis,
wherein the centering jig comprises a centering ring to receive the hole saw, and
wherein, when assembled for cutting, the hole saw has a circumferential cutting surface comprising a first opening and the centering ring has a circumferential surface comprising a second opening, the first and second openings to allow the hole saw and the centering ring to be pushed in a direction transverse to the center axis around a line.
2. The tool according to claim 1 , further comprising:
a base carrier and a saw blade,
wherein the base carrier and the saw blade are attached to one another, and
wherein an outer circumference of the saw blade is smaller than an inner circumference of the centering ring.
3. The tool according to claim 2 , wherein the saw blade is free to move within the centering ring as a result of the outer circumference of the saw blade being smaller than the inner circumference of the centering ring.
4. The tool according to claim 1 , wherein the centering ring has at least one dowel to fix the centering ring on a wall through which the line passes.
5. The tool according to claim 1 , wherein
the centering ring has a first axis, and
the hole saw has a second axis which is parallel to the first axis when the hole saw is in the centering ring.
6. The tool according to claim 1 , wherein at least one of the first opening and the second opening is less than one quarter of the circumference of a corresponding one of the hole saw and centering ring.
7. The tool according to claim 1 , wherein the hole saw has exactly one saw blade.
8. The tool according to claim 1 , further comprising a hand-controlled actuator coupled to the hole saw and to move the hole saw when a force is applied.
9. A method for creating a wall opening around a line already projecting from a wall, the method comprising:
attaching the centering ring of the tool according to claim 1 to a wall,
pushing the centering ring around the line through the second opening,
fixing the centering ring relative to the wall,
inserting the hole saw into the centering ring and around the line, and
rotating the hole saw around the center axis within the centering ring.
10. The method according to claim 9 , further comprising:
inserting of a fire-protection grommet into the wall opening.