EP2875888B1 - Tool, system and method for separating a head from a shaft - Google Patents

Description

The invention relates to a tool for separating a head from a shaft having the features of the preamble of claim 1, a system comprising such a tool and a head and a shaft having the features of the preamble of claim 8 and a method for separating a head from one Shaft with the tool having the features of the preamble of claim 10. Such a tool, system and method is for example from the US 5 984 272 A out.

The invention is particularly intended to separate the head from an anchor which is anchored in an anchorage, so that the head rests against a surface of the anchorage or a component disposed thereon. Anchored means that the anchor is anchored in the anchorage. The intended application of the invention is the removal of fire protection panels on tubbing in tunnels, for example for testing, inspection or maintenance purposes. If the fire protection plates with anchors are fastened to the tubbings on the inside, heads of shafts of the anchors must be separated in order to be able to remove the fire protection plates. Since the head of an anchor rests on the surface of the fire protection plate, when the anchor is anchored as intended, the shaft of the anchor is inaccessible. It should be borne in mind that anchors used in tunnel construction must be made of stainless steels, for example grade A4 or even grade 1.4529, ie steels of high strength and toughness. However, the invention is not limited to severing heads of high strength and / or toughened steel anchors, but is generally applicable to severing heads of shafts of any material.

The object of the invention is to provide an easily manageable tool for separating a head of a shaft when the shaft is anchored in an anchorage and the head rests against a surface of the anchor base or a component disposed thereon. The tool is also intended for heads and shanks made of steels higher Strength and toughness are suitable. The term "tool" is to be interpreted broadly and may include, for example, a device. It is another object of the invention to provide a system with such a tool and a head and a shaft and a method for separating a head from a shaft with such a tool.

This object is achieved by the features of claims 1, 8 and 10. The tool according to the invention has at least two jaws with cutting edges, which can be moved towards one another and moved away from one another. Moving the jaws and cutting toward each other is also referred to as closing and moving the jaws and the cutting away from each other also as opening the tool or the jaws. The jaws have a projecting cutting edge and a recessed cutting edge, which are arranged, for example, side by side on the jaw. The cutting edges are arranged and the tool is designed so that when closing the jaws, the projecting cutting edges come so close to each other that they separate a shaft located between them. The projecting blades may be arranged to contact each other when the jaws are closed or, with the jaws closed, a gap exists between the projecting blades which is so small that the shank between the blades will break despite the gap between the projecting blades. The design is dependent on a diameter and a material of the shaft to be separated with the tool.

The recessed cutting edges are spaced from each other when the jaws are closed, which is about as large or larger as the shaft is thick. To remove the head from the shaft, the recessed cuts are first used: The tool according to the invention is attached to the head so that the recessed cutting edges on a surface of an anchorage or a component disposed thereon or with the smallest possible distance from the surface against a circumference of the head reach. Subsequently, the tool is closed, with the jaws and the blades move towards each other. The recessed cutting edges on the circumference of the head pass between the head and the surface, thereby lifting the head slightly, for example about 1 mm to 2 mm, from the surface and pulling the shaft out of the anchor base accordingly. For example, expanding expansion anchors can always be pulled out so far from an anchorage in which they are anchored. Post-spreading anchor, which is in an anchor hole in anchored to an anchorage, spread, ie spread on when the anchor hole widens, for example, as a result of cracking in a tensile zone of the anchorage. In particular, the post-expanding armature is a bolt anchor having a spreading cone widening in diameter opposite the direction of insertion of the armature into a borehole, on which an expansion sleeve displaceable in the longitudinal direction along the shaft of the expansion armature is arranged. The re-spreading takes place at a tensile stress of the expansion anchor, which pulls the expansion anchor a short distance from the Ankergrurid by the shank arranged on the expansion cone further pulled into the slidably disposed on the shaft expansion sleeve and the expansion sleeve is widened in the radial direction. But other anchors, nails and the like. Can be pulled out a short distance from an anchorage by the recessed edges of the tool according to the invention as described attached to the circumference of the head and penetrate by closing the jaws between the head and the surface. Because the recessed cutting edges are not used for cutting, but rather like cutting wedges between the head and the surface, the recessed cutting edges are comparatively slightly stressed and therefore relatively sharp, without breaking off or breaking out during use. Sharp cutting enables or at least facilitates penetration between a head resting on a surface and the surface. In particular, the stress on the recessed cutting edges of the tool according to the invention is independent of the material of the shank from which the head is to be cut, because the recessed cutting edges do not separate the shank. With closed jaws, the distance between the recessed cutters is preferably at least as great as the shank is thick, so that the recessed cutters do not rest or lie against the shaft without force. It is also conceivable a slightly smaller distance of the recessed cutting each other with closed jaws. In any case, their distance should be chosen so large that a contact force of the recessed cutting edges on the shank with closed jaws does not damage the recessed cutting edges, even if they are sharp-edged.

After pulling the shaft a short distance of, for example, 1 mm to 2 mm from the anchor base with the recessed cutting edges tool according to the invention is opened so that the protruding cutting so far away from each other that between the head and the surface on the shaft can be recognized. By re-closing the jaws, the shaft of cut the protruding cutting and thus separated the head from the shaft. The projecting blades may be rounded or blunt, which they preferably are, so that they withstand the stress of cutting the shaft. By "blunt" is common that the projecting cutting, for example, have a narrow, flat surface instead of an edge. As the tool pulls the shank out of the anchoring base until it is accessible to the projecting cutting edge, the protruding cutting edges can be rounded or blunted to such an extent that they can withstand the severing of a shank made of a steel of high strength and toughness.

The invention enables a low-cost tool, with which the heads of shafts can be quickly separated by shutting the tool twice shafts, even if the shanks are made of a steel of high strength and toughness.

A preferred embodiment of the invention proposes that the jaws have abutment surfaces which bear against the surface when the tool is attached to the head to be severed or the shank of the tool to be severed and support the tool on the surface there. The recessed cutting edges are in a plane with the abutment surfaces, wherein the abutment surfaces may also be rounded. For example, the abutment surfaces end at the recessed cutting edges. This embodiment of the invention makes it possible to attach the tool according to the invention to a head of a shaft anchored in the anchor base, such that the recessed cutters bear against the surface when they reach the circumference of the head. This allows for the best possible penetration of the recessed cutters between the head and the surface when closing the jaws.

Preferably, the jaws are formed at least in the region of the recessed cutters in the manner of wedges, which act as wedges when penetrating between the head and the surface and lift the head by wedging force from the surface, wherein the jaws are supported on the surface. The jaws have two wedge surfaces whose transition form the preferably sharp-edged, recessed cutting. One of the wedge surfaces is, for example, the abutment surface of the jaws, with which the jaws are supported on the surface when the shaft is pulled out of the anchorage. The other wedge surfaces engage under the head and press it from the surface when the jaws are closed. The wedge surfaces can be flat or, for example, also rounded, the abutment surfaces, if they are rounded, preferably convex and the other wedge surfaces, when rounded, are preferably concavely rounded.

A preferred embodiment of the invention provides for a lateral stop of the tool or the jaws at one end of the projecting cutting edges. The stop abuts the side of the head to be separated from the shaft when the projecting blades between the head and the surface are attached to the shaft. The stop simplifies positioning of the tool when attaching the projecting cutting edges on the shaft. For the recessed cutting the projecting cutting edges can form a lateral stop.

Preferably, the tool according to the invention is a hand tool, d. H. a hand-held tool, in particular, it is a pair of pliers. This has the advantage that the tool requires no power supply. As pliers, the tool according to the invention may for example be a side cutter, wherein the projecting and the recessed cutting edges are arranged one behind the other on one side of the jaws or the projecting edges on one side and the recessed edges on the other side of the jaws. An embodiment of the invention provides a front cutter as a pliers, in which the cutting edges are arranged at the front, a pliers joint distal ends of the jaws. The pliers can be a lever pliers with a force translating lever mechanism.

The peripheral surface of the head to be separated from the shaft may be perpendicular to the surface when the head abuts the surface. Even then, in most cases, the recessed edges of the tool according to the invention will force between the head and the surface when the jaws are closed, especially when the recessed edges are sharp-edged. However, it facilitates the placement of the tool according to the invention, the penetration of the recessed cutters between the head and the surface, the lifting of the head from the surface and the withdrawal of the stem a short distance from the anchor base when the head has an undercut on the circumference. The undercut may be formed, for example, by a rounded peripheral edge of the head or a chamfer on the circumference of the head, which tapers to the surface, ie to the shank. A low undercut that is so high is enough the recessed cutters can reach them when the head abuts the surface. The undercut is formed such that an end of the undercut remote from the shaft has a greater distance from a bottom of the head than the recessed cutting edges from the abutment surface of the tool. A head with such a frusto-conical undercut is described in one embodiment. In particular, the peripheral surface of the head is frusto-conical and tapers in the direction of the shaft. The frusto-conical, the undercut forming peripheral surface of the head is axially higher than the distance of the recessed edges of the tool from the abutment surfaces, so that the recessed edges when attaching and closing the tool against the frusto-conical peripheral surface of the shaft to be separated from a shaft head, when the tool with its abutment surfaces on a surface or an attached object and the bottom of the head also rests on the surface.

In one embodiment, a despreading expansion anchor with a shaft and a head to be separated from the shaft is described. A nachspreizender expansion anchor is particularly suitable for separating his head with the tool according to the invention, because its shaft can be pulled out as already explained as in a Nachspreizen a short distance from the anchorage.

The inventive method has already been explained with reference to the above explanations of the tool according to the invention, which is referred to avoid repetition.

The invention will be explained in more detail with reference to an embodiment shown in the drawing:

Figur 1

ein Werkzeug zum Abtrennen eines Kopfs von einem Schaft gemäß der Erfindung;

Figur 2

einen vorderen Teil des Werkzeugs aus Figur 1 etwas schräg gestellt in größerer Darstellung und von einer gegenüberliegenden Seite;

Figur 3

einen nachspreizenden Spreizanker mit einem Schaft mit einem Kopf;

Figur 4

ein Ansetzen des Werkzeugs aus Figur 1 an einem Kopf eines Schafts;

Figur 5

ein Herausziehen des Schafts aus einem Ankergrund mit dem Werkzeug aus Figur 1; und

Figur 6

ein Abtrennen des Kopfs vom Schaft mit dem Werkzeug aus Figur 1.

Show it:

FIG. 1

a tool for severing a head from a shaft according to the invention;

FIG. 2

a front part of the tool FIG. 1 slightly inclined in a larger view and from an opposite side;

FIG. 3

a despreading expansion anchor with a shaft with a head;

FIG. 4

a preparation of the tool FIG. 1 on a head of a shaft;

FIG. 5

pulling the stem out of an anchorage with the tool FIG. 1 ; and

FIG. 6

a separation of the head from the shaft with the tool FIG. 1 ,

This in FIG. 1 illustrated, inventive tool 1 is a Hebelvornschneider 2, so a pair of pliers with a lever mechanism 3 to a power transmission, the arranged transversely to the pliers cutting 4, 5 (see FIG. 2 ) has at front ends of two jaws 6 of the forceps. The tool 1 is thus a hand tool or a hand-operated tool 1. By pivoting of levers 19, the jaws 6 together with the cutting edges 4, 5 via the lever mechanism 3 and moved apart, which also as closing and opening of the jaws 6 and des Tool 1 can be construed. FIG. 2 shows a front part of the tool 1 with closed jaws 6 from an opposite side as. FIG. 1 , The jaws 6 each have on one side a recessed edge 4 and a projecting edge 5 next to the recessed edge 4 on the other side of the jaws 6. With closed jaws 6, the projecting blades 5 abut against each other, whereas the recessed blades 4 have a distance from each other. The recessed cutting edges 4 are sharp-edged, whereas the projecting cutting edges 5 are rounded. Front faces of the jaws 6 form abutment surfaces 7, which end at the recessed cut 4. On the inside, the jaws 6 have wedge surfaces 8, which likewise end at the recessed edges 4, so that 6 wedges 9 are formed on the jaws, which are bounded by the wedge surfaces 8 and the abutment surfaces 7 and pointed to the sharp-edged, recessed cutting edge. 4 leak. In the embodiment, the wedge surfaces 8 are concave, but this is not mandatory for the invention.

The projecting blades 5 are formed on wedges 10 projecting from the jaws 6 inwardly towards each other. On the side of the jaws 6, on which the projecting cutting edges 5 are arranged, the tool 1 has a lateral stop 11.

The tool 1 is used for separating a head 12 from a shaft 13 of an in FIG. 3 The expansion anchor 20 serves for fastening, for example, fire protection plates 14 to an anchorage 15, for example a tubbing in a tunnel (FIG. FIG. 4 ). The shaft 13 passes through the fire protection plate 14 and is anchored in the tubbing 15. The tubbing forms the anchoring base 15. In the exemplary embodiment, the side of the fire protection plate 14 facing away from the anchoring base 15 forms a surface 1.8. By train, the expansion anchor 20 can be nachspreizen, ie further spread, for example, if an anchor hole in which the expansion anchor is anchored, as a result of cracking in a tensile zone of the tubing or anchor base 15 expands. By acting on the shaft 13 of the Spreizarikers pulling force of the shaft 13 is pulled out a short distance from the tubbing or anchoring ground 15 and spreads by. The shank 13 has an expansion cone 21 at its head far end, on which a slotted expansion sleeve 22 is arranged. When re-spreading is pulled by train on the shaft 13 of the expansion cone 21 further into the expansion sleeve 22 and expands it more, that spreads the expansion sleeve on, which is referred to as retightening. To form an undercut 17, the head 12 has a chamfer 16 on its circumference, which tapers in the direction of the shaft 13. The chamfer 16 is a frusto-conical surface on the circumference of the head 12, which tapers in the direction of the shaft 13 and forms a peripheral surface of the head 12.

To separate the head 12 from the shaft 13 of the expansion anchor 20, the tool 1 according to the invention as in Figure. 4 drawn with open jaws 6 set so that the abutment surfaces 7 abut a surface 18 of the fire protection plate 14, the head 12 of the expansion anchor 20 is located between the recessed cutting edge 4 and the blades 4 when closing against the circumference of the head 12 arrive. The recessed cutting edges 4 reach against the chamfer 16, which forms the undercut 17 of the head 12. Upon further closing of the jaws 6, the recessed cutting 4 squeeze between the head 12 and the fire protection plate 14, wherein the Hineinzwängen is favored by the frusto-conical chamfer 16 on the circumference of the head 12, extending in the direction of the shaft 13 and thus in the direction of the fire protection board 14 rejuvenated. In this state, an end of the undercut (17) facing away from the shaft has a greater distance from an underside of the head (12) than the recessed cutting edges (4) from the abutment surface (7). By wedge effect of the facing wedge elements 9 on the inner sides of the jaws 6, at the ends of the recessed cutting edge. 4 are formed, the head 12 is pressed or lifted off the fire protection plate 14 and the shaft 13 accordingly pulled out of the tubbing or anchorage 15 ( FIG. 5 ). The head 12 is lifted by, for example, about 2 mm from the fire protection plate 14 and the shaft 13 is also pulled out by about 2 mm from the tubbing or anchorage 15 accordingly. The shaft 13 is now accessible between the head 12 and the fire protection plate 14. When attaching the tool 1, the projecting blades 5 help in a lateral positioning, because the projecting blades 5 and the wedges 10, on which they are formed and which are arranged adjacent the projecting blades 4, laterally on the circumference of the head 12 can be applied.

After briefly pulling the shaft 13 out of the tubing or anchoring base 15, the jaws 6 are opened again and the tool 1 is offset laterally so that the shaft 13 is now located between the projecting blades 5. For lateral positioning of the lateral stop 11 of the tool 1, which can be applied to the circumference of the head 12 is used. Subsequently, the jaws 6 are closed again, the projecting blades 5 penetrate into the shaft 13 and severing it, so that the head 12 is separated from the shaft 13, as in FIG. 6 shown.

After separation of the heads 12 of all expansion anchors, with which the fire protection plate 14 is attached to the tubing or anchorage 15, the fire protection plate 14 can be removed from the anchorage. For a renewed attachment, the shafts 13 of the expansion anchor 20, which protrude with removed fire protection plate 14 from the tubing or anchorage 15, taken in the tubbing or anchorage 15. Thereafter, the fire protection plate 14 can be fastened with new expansion anchors 20 again on the tubbing or anchorage 15.

In tunnel construction, expansion anchors are made of corrosion-resistant steel of high strength and toughness, for example grade A4 or 1.4529. For cutting a correspondingly stable tool 1 is necessary. Because the recessed blades 4 are not used to sever the shaft 13, their stress is comparatively low and they may therefore be sharp-edged to allow them to be forced between the head 12 resting against the fire protection plate 14 and the fire protection plate 14. The projecting cutting edges 5 used for cutting the shaft 13 can be by their rounding or by a blunt formation (not shown) so stable that they are able to sever the shaft 13 without being damaged, even if the shaft 13 is made of a steel of high strength and toughness.

LIST OF REFERENCE NUMBERS Tool, system and method for severing a head from a shaft

1

Tool

2

Lever End Cutting

3

lever mechanism

4

recessed edge

5

projecting cutting edge

6

jaw

7

Abutment surface.

8th

wedge surface

9

wedge

10

wedge

11

lateral stop

12

head

13

shaft

14

Fire protection panel

15

Ankergrund

16

chamfer

17

undercut

18

surface

19

lever

20

expansion anchor

21

expansion cone

22

expansion sleeve

Claims (10)

1. Tool for separating a head (12) from a shank (13), with at least two jaws (6) having blades (4, 5), which jaws are movable towards one another, the jaws (6) having set-back blades (4) which, when the jaws (6) are in the closed position, are spaced apart from one another by a distance which is at least approximately as large as the shank (13) is thick, characterised in that the jaws (6) have projecting blades (5) which, when the jaws (6) are closed, come so close together that they cut through a shank (13) located therebetween.
2. Tool according to claim 1, characterised in that the projecting blades (5) are rounded or blunt.
3. Tool according to claim 1 or 2, characterised in that the jaws (6) have counter-bearing faces (7) for supporting the tool (1) against a surface (18), and the set-back blades (4) are located in the same plane as the counter-bearing faces (7) of the jaws (6).
4. Tool according to claim 3, characterised in that the jaws (6) have wedge faces (8) which adjoin the set-back blades (4) and form the wedges (9) with the counter-bearing faces (7).
5. Tool according to any one of the preceding claims, characterised in that at an end of the projecting blades (5) remote from the set-back blades (4) the tool (1) has a stop (11) for the head (12) to be separated from the shank (13).
6. Tool according to any one of the preceding claims, characterised in that the tool (1) is a hand tool.
7. Tool according to claim 6, characterised in that the tool (1) is a pair of pliers.
8. System for separating a head (12) from a shank (13), having a tool according to any one of claims 3 - 7 which has at least two jaws (6), which are movable towards one another, with a projecting blade (5) and a set-back blade (4) and with a counter-bearing face (7) in the plane of which the set-back blades (4) are located, wherein when the jaws (6) are closed the projecting blades (5) come so close together that they cut off a shank (13) located therebetween and the set-back blades (4) are spaced apart from one another by a distance which is at least approximately as large as the shank (13) is thick, and with a shank (13) having a head (12), characterised in that the jaws (6) of the tool (1) have a counter-bearing face (7) for supporting the tool (1) against a surface (18); the head (12) of the shank (13) has an undercut (17); and an end of the undercut (17) remote from the shank is spaced a greater distance apart from an underside of the head (12) than the set-back blades (4) are spaced apart from the counter-bearing face (7).
9. System according to claim 8, characterised in that the head (12) and the shank (13) are components of an expansible anchor capable of follow-up expansion.
10. Method of separating a head (12) from a shank (13), wherein the shank (13) is fixed in an anchoring substrate (15) and the head (12) rests against a surface (18), having a tool (1) according to any one of claims 3 - 7 which has at least two jaws (6) with a projecting blade (5) and a set-back blade (4), wherein when the jaws (6) are closed the projecting blades (5) come so close together that they cut off a shank (13) located therebetween and the set-back blades (4) are spaced apart from one another by a distance which is at least approximately as large as the shank (13) is thick, and with counter-bearing faces (7) for supporting the tool (1) against the surface (18), characterised in that the jaws (6) are positioned against the head (12) so that the counter-bearing faces (7) rest against the surface (18); the jaws (6) are closed so that the set-back blades (4) pass between the head (12) and the surface (18) and the head (12) is lifted away from the surface (18) and the shank (13) is pulled slightly out of the anchoring substrate (15); the jaws (6) are subsequently opened again and the projecting blades (5) of the tool (1) are positioned against the shank (13) between the head (12) and the surface (18) and the jaws (6) are then closed so that the projecting blades (5) cut through the shank (13).

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