DE10146700B4 - Tool for profiling a hole - Google Patents

Abstract

Tool (1) for profiling a bore (2), in particular in a screw (3) comprising
A longitudinal axis (6) along which the tool (1) extends,
A cutting edge (9),
- Which is arranged at a first longitudinal end (7) of the tool (1) and
- Which is arranged with changing distance to the longitudinal axis (6) around this,
- engaging means (15) for a tool for driving the tool (1) into a bore (2) in a cutting direction along the longitudinal axis (6),
- Wherein the engagement means (15) at a second longitudinal end (8) of the tool (1) are arranged, and
- A rotary tool portion (13), viewed in the cutting direction behind the cutting edge (9) is arranged, wherein the outer peripheral surface of the rotary tool portion (13) and the cutting edge (9) in a projection in the direction of the longitudinal axis (6) lie on each other.

Description

The The invention relates to a tool for profiling a bore, in particular in a screw. With such a tool, in particular screws, which are screwed into threaded holes and their screw head are broken off in the region of the screw shank, machined so be that they can be removed from the threaded hole again.

So far have known tools for unscrewing broken screws a pin with an external thread on, which to a longitudinal end of the pin tapers. The tool is with an opposite thread to that thread formed having the screw to be removed. To remove the screw becomes a bore lengthwise a longitudinal axis the screw inserted into this. The thread of the tool is formed as a cutting thread, so that this screwed into the hole can be, with an internal thread is cut into the hole. Due to the conical configuration of the cutting thread is the Resistance during the screwing of the tool larger until for tightening the tool, a limit torque is exceeded, in which the screw can be screwed out of the threaded hole. Because such tools too for little ones Screw sizes can be used have to be The se have a very small diameter and can when Slight cutting off cutting process. Especially with stuck corroded screws The risk of breaking off is very large, since the to turn off the Required torques far exceed the maximum torques of the bolt Exceed tool.

The DE 198 05 578 C2 shows a tool for producing a circular spline with a cutting edge, which is arranged at a first longitudinal end of the tool and is arranged with varying distance to a longitudinal axis about this. Furthermore, the tool has engagement means for a tool for driving the tool into a bore, wherein the engagement means are arranged on a second longitudinal end of the tool. Furthermore, the tool has a portion which, viewed in the cutting direction, is arranged behind the cutting edge and on which a tool can engage.

US 3 997 429 A shows a chisel made of a body having a hexagonal profile. At one end of the main body of this a cutting tool portion is formed, which is viewed in cross-section square and deviates from the cross section of the body. The cutting tool portion forms a straight cutting edge.

task The invention is to provide a tool having a bore prepared in a screw so that the screw with little effort can be rotated from a threaded hole, the tool preferably should be stable.

• – eine Längsachse, entlang welcher sich das Werkzeug erstreckt,
• – eine Schneidkante,
• – die an einem ersten Längsende des Werkzeugs angeordnet ist und
• – die mit sich verändernden Abstand zur Längsachse um diese angeordnet ist,
• – Angriffsmittel für ein Werkzeug zum Eintreiben des Werkzeugs in eine Bohrung in einer Schneidrichtung entlang der Längsachse,

wobei die Angriffsmittel an einem zweiten Längsende des Werkzeugs angeordnet sind, und

• – ein Drehwerkzeugabschnitt, der in Schneidrichtung betrachtet hinter der Schneidkante angeordnet ist, wobei die Außenumfangsfläche des Drehwerkzeugabschnitts und die Schneidkante in einer Projektion in Richtung der Längsachse aufeinander liegen, gelöst.

The object is achieved by a tool for profiling a bore, in particular in a screw comprising

• A longitudinal axis along which the tool extends,
• A cutting edge,
• - Which is arranged at a first longitudinal end of the tool and
• - which is arranged with changing distance to the longitudinal axis about this,
• Engaging means for a tool for driving the tool into a bore in a cutting direction along the longitudinal axis,

wherein the engaging means are arranged at a second longitudinal end of the tool, and

• - A rotary tool portion, which is arranged behind the cutting edge when viewed in the cutting direction, wherein the outer peripheral surface of the rotary tool portion and the cutting edge lie in a projection in the direction of the longitudinal axis to each other, solved.

The Tool leaves to drive axially into the bore of a screw, the cutting edges a Create a cross section of the hole that deviates from a circle. Preferably, the cutting edge has a hexagonal shape, so that a hexagon profile is formed. After the cutting process let yourself Insert a hexagon key into this hexagon socket with the screw shaft a broken screw is ausdrehbar.

The Tool is not loaded on torsion but only on compressive stresses. The compressive stresses are not dependent on the torque that to unscrew the screw is required. The compressive stresses are only on the material of the screw and the depth of cut Cutting edge dependent. As the depth of cut depends on the diameter of the bore can be kept relatively low, the loads of the tool are significantly less when driving the strength of the tool. Thus the danger of the breaking off is of the tool significantly reduced.

So not a separate hexagon key sel must be used to unscrew the screw, the rotary tool portion is provided, which is arranged behind the cutting edge when viewed in the cutting direction, wherein the outer peripheral surface of the rotary tool portion and the cutting edge lie in a projection in the direction of the longitudinal axis. Here, the dimensions of the outer peripheral surface of the rotary tool portion may be slightly smaller than that of the cutting edge to avoid interference fit of the rotary tool portion in the profiled bore.

It may be a connecting portion for connecting the tool with a Be provided rotary actuator. The connection section can in this case Be formed cross-section hexagonal. Thus, the tool can to unscrew the screw with the simplest tools. For example, a ratchet or a cordless screwdriver on the in the tool located hole to be plugged.

Around an arranged in the cutting direction behind the cutting edge free space for a better To be able to provide machining is the cutting edge Part of a cutting tool section, the cutting edge immediately connected and an open space , wherein the cutting tool portion of the cutting edge starting conically tapering is trained.

At the first longitudinal end the tool may be provided with an axially projecting centering projection, in a projection in the direction of the longitudinal axis within the cutting edge is arranged. This leaves the tool before driving into the hole on the hole put on, with the centering already protrudes into the hole, so that the tool is centered to the hole. The centering approach Here, preferably, starting from the cutting edge is tapered conically.

One preferred embodiment is explained in more detail with reference to the drawings.

Here in shows

1 a longitudinal section by a screw with a driven into a bore inventive tool and

2 a view of the tool according to the 1 in view II-II.

In the 1 and 2 is a preferred embodiment explained in more detail. They will be described together below.

An inventive tool 1 is in a hole 2 a screw 3 , whose screw head is broken off, partially driven. The screw 3 is in a threaded hole 4 a component 5 screwed.

The tool 1 has a longitudinal axis 6 on and is concentric in the hole 2 driven so that the longitudinal axis 6 simultaneously the longitudinal axis of the hole 2 represents. The tool 1 has a first longitudinal end 7 on, with which the tool 1 into the hole 2 is driven. Furthermore, the tool points 1 a second longitudinal end 8th on, which from the hole 2 protrudes. At the first longitudinal end 7 is a cutting edge 9 provided, which by a cutting surface 10 and an open space 11 is formed. The cutting surface 10 is transverse to the longitudinal axis 6 arranged and the open space 11 is starting from the cutting edge 9 conically towards the second longitudinal end 8th formed rejuvenating. The open space 11 is part of a cutting tool section 12 of the tool 1 ,

Towards the second longitudinal end 8th closes to the cutting tool section 12 one in the hole 2 Submerged rotary tool section 13 at. The turning tool section 13 has a hexagonal cross-section, wherein in a projection in the direction of the longitudinal axis 6 the outer peripheral surface of the rotary tool section 13 and the cutting edge 9 lie on one another. This ensures that the turning tool section 13 perfectly fitting in the cut profile of the bore 2 is insertable.

The turning tool section 13 goes seamlessly into a connecting section 14 over, which has the same cross-section as the rotary tool section 13 , On the connecting section 14 For example, a ratchet or a cordless screwdriver can be attached to the tool 1 to rotate and due to the rotationally fixed connection of the tool 1 over the turning tool section 13 in the hole 2 to unscrew the screw.

An endface 15 at the second longitudinal end 8th is perpendicular to the longitudinal axis 6 arranged and allows the tool 1 by means of a hammer in the hole 2 to be able to collect and thus the bore 2 to profile. To before driving the tool 1 this concentric to the hole 2 Being able to align as simply as possible is a centering approach 16 before, starting from the cutting surface 10 protrudes axially and starting from the cutting surface 10 conically tapered. The base diameter of the spigot 16 in the area of the cutting surface 10 corresponds approximately to the diameter of the bore 2 so that when putting the tool 1 on the hole 2 the centering approach 16 into the hole 2 protrudes and the tool 1 aligns to the hole.

1

Tool

2

drilling

3

screw

4

threaded hole

5

component

6

longitudinal axis

7

first longitudinal end

8th

second longitudinal end

9

cutting edge

10

cutting surface

11

open space

12

Cutting tool section

13

Rotary tool section

14

connecting portion

15

end face

16

Spigot

Claims (7)

Tool ( 1 ) for profiling a bore ( 2 ), in particular in a screw ( 3 ), comprising - a longitudinal axis ( 6 ), along which the tool ( 1 ), - a cutting edge ( 9 ), - at a first longitudinal end ( 7 ) of the tool ( 1 ) is arranged and - the with changing distance to the longitudinal axis ( 6 ) is arranged around these, - submission means ( 15 ) for a tool for driving the tool ( 1 ) into a hole ( 2 ) in a cutting direction along the longitudinal axis ( 6 ), - where the plea ( 15 ) at a second longitudinal end ( 8th ) of the tool ( 1 ), and - a turning tool section ( 13 ), viewed in the cutting direction behind the cutting edge ( 9 ) is arranged, wherein the outer peripheral surface of the rotary tool section ( 13 ) and the cutting edge ( 9 ) in a projection in the direction of the longitudinal axis ( 6 ) lie on one another. Tool according to claim 1, characterized in that the cutting edge ( 9 ) has a hexagonal shape. Tool according to one of claims 1 or 2, characterized in that a connecting portion ( 14 ) to connect the tool ( 1 ) is provided with a rotary drive. Tool according to claim 3, characterized in that the connecting portion ( 14 ) is hexagonal in cross section. Tool according to one of claims 1 to 4, characterized in that the cutting edge ( 9 ) Component of a cutting tool section ( 12 ), which is against the cutting edge ( 9 ) and an open space ( 11 ), wherein the cutting tool section ( 12 ) from the cutting edge ( 9 ) is formed starting conically tapered. Tool according to one of claims 1 to 5, characterized in that at the first longitudinal end ( 7 ) of the tool ( 1 ) an axially projecting spigot ( 16 ) which is projected in the direction of the longitudinal axis ( 6 ) within the cutting edge ( 9 ) is arranged. Tool according to claim 6, characterized in that the centering projection ( 16 ) starting from the cutting edge ( 9 ) conically tapered.