Cutting device for perforating a pipe

Abstract

Cutting device (1) for perforating a tube (18), with a head part (2) which can be inserted into a tube (18) at a front end (4), wherein the head part (2) extends along a longitudinal axis (6) from the front end (4) of the head part (2) to a rear end (5) of the head part (2); and a cutting tool (11) pivotably mounted on the head (2) with a free end (15) having a cutting edge (16), wherein the cutting tool (11) is pivotably mounted about a pivot axis (12) which extends transversely to the longitudinal axis (6) of the head (2), wherein the cutting tool (11) is pivotable from a first position in which the free end (15) of the cutting tool (11) is turned away from the front end (4) of the head (2) towards a second position in the direction of the front end (4) of the head (2), and wherein the cutting tool (11) is designed such thatthat the cutting tool (11) in the first position projects beyond the outer circumference of the head part (2) such that when the head part (2) is inserted into a tube (18) and pulled rearward (14) towards the rear end (5) of the head part (2), the cutting tool (11) wedges its cutting edge (16) against the tube wall (19) of the tube (18) and penetrates the tube wall (19), so that by further retraction of the head part (2) rearward (14), the cutting tool (11) pivots towards the front end (4) to penetrate deeper into the tube wall (19) and pierce the tube wall (19), characterized in that the cutting device (1) has adjustable adjusting means which are configured to adjust a position of the cutting tool (11) about the pivot axis (12), wherein the adjusting means are relative to the head part (2) comprising an actuator (23) movable along the longitudinal axis (6) and a coupling mechanism (24, 25),which is designed to couple the actuator (23) with the cutting tool (11) in such a way that movements of the actuator (23) in different directions along the longitudinal axis (6) are transmitted to the cutting tool (11) in order to pivot the cutting tool (11) in a first pivoting direction (21) towards the front end (4) of the head part (2) to the second position and in a second pivoting direction (22) opposite to the first pivoting direction (21), and wherein the coupling mechanism (24, 25) is designed to be releasable in such a way that the cutting tool (11) can decouple itself from the actuator (23) when wedged against the pipe wall (19) and subsequently pivoted towards the front end (4) by further retraction of the head part (2) to the rear (14).

Description

TECHNICAL AREA

[0001] The invention relates to a cutting device for perforating a tube, comprising a head part that can be inserted into the tube with its front end facing forward. The head part extends along a longitudinal axis from its front end to a rear end. A pivotably mounted cutting tool is attached to the head part, the cutting tool having a free end with a cutting edge that serves to create a perforation in the tube. BACKGROUND OF THE INVENTION

[0002] Devices of the type mentioned above are used to create perforations, or holes, in the inside of a pipe and are particularly useful in applications where pipes must be at least partially destroyed before further use. For example, for safety reasons, it is often necessary to perforate heat exchanger tubes before they are plugged to allow pressure equalization. For this purpose, significant perforation in the pipe is sufficient. Other examples of applications for these devices include cutting steel, brass, and copper tubes in condensers, coolers, or boilers.

[0003] A known cutting device of this type, based on prior art, is designed such that it is first inserted into a pipe and then creates a perforation in the pipe wall by applying a rotational force. This cutting device has a head to which a cutting tool is attached. By applying a torque and rotating the cutting device, for example, using a wrench, the cutting tool pivots laterally out of the head about an axis extending longitudinally along the head and cuts into the pipe wall. Before the cutting tool can be removed from the pipe, a torque must again be applied, this time in the opposite direction, causing the cutting tool to retract from the pipe wall and retract laterally into the head. Only then can the cutting tool be pulled out of the pipe by axial tensile forces.

[0004] However, a disadvantage of such devices is the comparatively complex mechanism for operating the cutting tool within the head. Using the cutting device generally involves several operating movements (turning, pulling), which can be perceived as cumbersome. Furthermore, the design proves to be expensive and prone to malfunction.

[0005] US 1 433 722 A shows a deep well casing ripper designed to be lowered into the casing of a deep well and operated to cut the lower end of a casing sleeve out of a coupling or collar.

[0006] US 3,581,395 A shows a tool for cutting the inside of a pipe at an angle.

[0007] The object underlying the invention is therefore to propose a device of the type mentioned above which enables simpler and more cost-effective perforation of pipes. SUMMARY OF THE INVENTION

[0008] The problem underlying the invention is solved by a cutting device for perforating pipes with the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] According to the invention, the cutting device comprises a cutting tool that is pivotably mounted about a pivot axis extending transversely to the longitudinal axis of the head. The cutting tool can be pivoted from a first position, in which the free end of the cutting tool is directed away from the front end of the head, i.e., essentially oriented rearward, towards the front end of the head, i.e., forward, to a second position. The cutting tool is designed such that, in the first position, it projects laterally beyond the outer circumference of the head in such a way that when the head is inserted into a tube with a corresponding inner diameter and pulled rearward, i.e., towards the rear end of the head, the cutting tool wedges itself with its cutting edge against the inside of the tube wall and, in particular, can penetrate the tube wall obliquely.The resistance causes the cutting tool to pivot forward around its pivot axis towards the front end by further retraction of the head, thus allowing the cutting tool to penetrate deeper into the pipe wall in order to pierce the pipe wall.

[0010] As the cutting tool pivots forward from its initial position, its free end moves outward relative to the longitudinal axis of the cutting head. Thus, it performs an outward pivoting motion from its initial position. This allows the cutting tool to penetrate deeper into the pipe wall, creating a perforation. On the side of the cutting head furthest from the cutting edge, relative to the longitudinal axis, the cutting head can rest against the inside of the pipe wall.

[0011] In contrast to the prior art, the cutting forces for creating the perforation in the pipe wall are generated by introducing axial forces. This significantly simplifies the entire cutting process, as positioning, actuating, and subsequently removing the cutting device all occur in the axial direction. Only the pivoting cutting tool is required on moving parts to create the perforation. This proves to be extremely cost-effective.

[0012] In principle, the pipes to be perforated by the cutting device are selected to have an inner diameter larger than the outer diameter of the head, so that the head can be inserted into the pipe and the cutting tool can wedge itself against the inside of the pipe wall. However, the cutting device according to the invention can readily be designed for a wide range of pipe inner diameters. In another embodiment of the invention, the extent to which the cutting tool projects beyond the outer circumference of the head in the first position is adjustable. This allows a single cutting device to be used for a large number of pipes with different inner diameters. In principle, however, the cutting device according to the invention can be dimensioned in a variety of ways to cover an even wider range of pipe inner diameters.

[0013] The cutting device has adjustable adjusting means configured to set a position of the cutting tool about the pivot axis, wherein the adjusting means comprise an adjusting element movable relative to the head part along the longitudinal axis and a coupling mechanism configured to couple the adjusting element to the cutting tool in such a way that movements of the adjusting element in different directions along the longitudinal axis are transmitted to the cutting tool in order to pivot the cutting tool in a first pivoting direction towards the front end of the head part to the second position and in a second pivoting direction opposite to the first pivoting direction, and wherein the coupling mechanism is designed to be releasable.that the cutting tool, when wedged against the pipe wall and subsequently pivoted towards the front end, can decouple itself from the actuator by further retracting the head part backwards.

[0014] The direction in which the cutting tool can pivot forward around the pivot axis towards the front end of the head is the first pivot direction. The first pivot direction also indicates the direction in which the cutting tool pivots forward during the cutting process. Accordingly, the second pivot direction indicates a direction in which the cutting tool can pivot around the pivot axis in the opposite direction to the first pivot direction, i.e., towards the rear end of the head or away from the second position.

[0015] The coupling mechanism is designed so that the actuator can couple with the cutting tool, enabling the actuator to exert actuating forces on the cutting tool. In the coupled state, the position of the actuator along its longitudinal axis correlates with a specific position of the cutting tool around its pivot axis. Movements of the actuator along its longitudinal axis are transmitted to the cutting tool, and the cutting tool can rotate around its pivot axis in either the first or second direction, corresponding to a movement of the actuator along its longitudinal axis. This makes it possible to set a specific position of the cutting tool, e.g., the first position, by adjusting the position of the actuator accordingly.

[0016] The cutting tool is decoupled from the actuator during the cutting process in such a way that movements of the actuator along its longitudinal axis (e.g., backwards) do not cause the cutting tool to return to its restoring position in the second pivoting direction. This also means that the cutting tool can rotate forwards around its pivoting axis when entering the pipe wall, while the actuator remains stationary along its longitudinal axis. While it is possible for physical contact between the cutting tool and the actuator to be maintained after decoupling, in the decoupled state, movement of the actuator along its longitudinal axis (e.g., backwards) does not cause the cutting tool to return to its restoring position. The cutting tool can rotate freely forwards.

[0017] This embodiment offers particular advantages with regard to the cutting process. To prepare for a cutting operation, the cutting tool can be coupled to the actuator, so that movements of the actuator relative to the head along the longitudinal axis are converted into a rotational movement of the cutting tool around the pivot axis. Movements of the actuator in one direction along the longitudinal axis (e.g., forwards) cause a pivoting movement of the cutting tool in the first pivoting direction, i.e., forwards towards the front end of the head. Movements of the actuator in the other, i.e., opposite, direction along the longitudinal axis (e.g., backwards) cause a pivoting movement of the cutting tool in the second pivoting direction, i.e., opposite to the first pivoting direction.As previously explained, adjusting the position of the actuator along the longitudinal axis relative to the head allows for the rotational positioning of the cutting tool. This proves particularly helpful when inserting the head into a pipe. The cutting tool can initially be positioned so that its cutting edge points backward, preventing it from contacting the pipe's inner wall when the cutting device is inserted. Once the cutting device is positioned at the point to be cut, the cutting tool can be extended using the actuator and brought into contact with the pipe wall to perform the cutting operation, for example, by moving it into the first position. The actuator can also be used to press the cutting tool against the inner wall to facilitate wedging it against the pipe wall.During the actual cutting process, the cutting tool is pivoted forward towards its front end. This decouples the cutting tool from the actuator, and the actuator no longer exerts any restoring forces on the cutting tool. This allows the cutting tool to perform the cutting process without any influence from the actuator. The ability to pivot the cutting tool in different directions while coupled to the actuator also makes it possible to abort a cutting process and retract the cutting tool back to its original position. The cutting device can then simply be pulled out of the pipe.

[0018] Another preferred embodiment of the invention is a cutting device for perforating a tube, comprising a head part which can be inserted into a tube at a front end, the head part extending along a longitudinal axis from the front end of the head part to a rear end of the head part; and a cutting tool pivotably mounted on the head part, the cutting tool having a free end and a cutting edge, wherein the cutting tool is pivotably mounted about a pivot axis which extends transversely to the longitudinal axis of the head part, wherein the cutting tool can be pivoted from a first position in which the free end of the cutting tool is turned away from the front end of the head part to a second position towards the front end of the head part, and wherein the cutting tool is designed such that when the head part is inserted into a tube and is pulled rearward towards the rear end of the head part,The cutting tool can wedge its cutting edge against the pipe wall and penetrate the pipe wall, so that by further retracting the head part backwards, the cutting tool pivots toward the front end to penetrate deeper into the pipe wall and pierce the pipe wall, the cutting device having adjustable adjusting means configured to set a position of the cutting tool about the pivot axis, the adjusting means comprising an adjusting element movable relative to the head part along the longitudinal axis and a coupling mechanism configured to couple the adjusting element to the cutting tool such that movements of the adjusting element in different directions along the longitudinal axis are transmitted to the cutting tool.to pivot the cutting tool in a first pivoting direction towards the front end of the head towards the second position and in a second pivoting direction opposite to the first pivoting direction, wherein the coupling mechanism is designed to be releasable such that the cutting tool, when wedged against the pipe wall and subsequently pivoted towards the front end, can decouple itself from the actuating element by further retraction of the head. A position of the cutting tool can be set by means of the actuating means. Thus, the cutting tool can be set before the initiation of the cutting process, i.e., before the head is pulled back, so that it projects beyond the outer circumference of the head in such a way that when the head is inserted into a pipe and pulled back towards the rear end of the head,The cutting tool wedges its cutting edge against the pipe wall. The adjusting mechanism allows the cutting tool to be extended from a position where it is fully retracted and oriented to the rear (i.e., not protruding beyond the outer circumference of the head) to a position where it extends beyond the outer circumference, thus wedging itself against the pipe wall when the head is retracted. A particular advantage is that the cutting tool can initially remain inside the head when being inserted into a pipe and is only extended once it reaches its target position within the pipe.

[0019] According to a further embodiment of the invention, the actuating element comprises a connecting rod movable along the longitudinal axis relative to the head, the front end of which is configured to couple with the cutting tool. As part of the actuating means, the position of the connecting rod along the longitudinal axis can be adjusted by the user of the cutting device.

[0020] According to a further embodiment of the invention, the actuating element is arranged on the side of the pivot axis of the cutting tool facing the rear end of the head part.

[0021] According to a further embodiment of the invention, the coupling mechanism is designed to automatically couple the actuator to the cutting tool by means of an actuating movement of the actuator in the direction of the cutting tool. The coupling mechanism can, for example, be designed to establish the connection between the cutting tool and the actuator by bringing the actuator into engagement or contact with the cutting tool.

[0022] According to a further embodiment of the invention, the releasable coupling mechanism comprises releasable positive locking means and / or frictional locking means. Interacting positive locking means and / or frictional locking means are preferably provided at an end of the actuator oriented towards the pivot axis of the cutting tool and on the cutting tool itself. The actuator can, in particular, comprise the connecting rod, which is movable along its longitudinal axis relative to the head, and at whose front end positive locking means and / or frictional locking means are provided. Corresponding positive locking means and / or frictional locking means are provided on the cutting tool, which can interact with the positive locking means and / or frictional locking means of the connecting rod to couple the connecting rod to the cutting tool.Coupling mechanisms based on positive locking and force locking include, in particular, snap-fit ​​connections, clamping connections, adhesive connections (e.g., adhesive connections, hook and loop connections) and, especially preferably, magnetic connections (magnetic couplings).

[0023] According to a further embodiment of the invention, the releasable coupling mechanism between the actuator and the cutting tool comprises a magnetic coupling. For this purpose, the actuator and the cutting tool can have magnetic connecting elements, preferably located at the front end of the connecting rod and on the cutting device. The actuator can, for example, have a magnetic element, such as a permanent magnet, preferably located at the front end of the connecting rod. The cutting tool can have a corresponding counter-element, for example, an iron element, configured to interact magnetically with the magnetic element of the connecting rod in order to be attracted and magnetically held by the magnetic element of the connecting rod. The cutting tool can also consist entirely or partially of a material (e.g., iron) suitable for coupling with the magnetic element of the connecting rod.

[0024] According to a further embodiment of the invention, the cutting tool comprises a control surface for engaging the actuator, wherein the control surface is configured such that a movement of the actuator along the longitudinal axis pivots the cutting tool towards the second position, or in the first pivoting direction. Particularly preferably, the cutting tool comprises a control surface for engaging a front end of the actuator, wherein the control surface is configured such that a movement of the actuator in the direction of the pivot axis pivots the cutting tool towards the second position, or in the first pivoting direction. A control surface can, for example, be provided by a back surface of the cutting tool that extends parallel to the pivot axis of the cutting tool.

[0025] Another embodiment of the invention provides that the adjusting means comprise actuator means, preferably in the form of an adjusting screw, to actuate the adjusting means when the cutting device is inserted into a pipe. The actuator means can, for example, have a threaded section that is screwed to a corresponding mating threaded section of the cutting tool. The threaded section of the actuator means can be part of an adjusting screw attached to or integrally formed with the adjusting element, which can also be actuated by the user when the cutting device is inserted.

[0026] Another embodiment of the invention provides that the cutting tool is arranged in a groove-like recess of the head part extending in the direction of the longitudinal axis. Preferably, the cutting tool is pivotably mounted in the recess. For this purpose, it can be pivotally mounted in the recess by means of a cylindrical pin extending transversely to the longitudinal axis of the head part. The pivot axis of the cutting tool is thus located within the outer circumference of the head part.

[0027] According to a further embodiment of the invention, the cutting device is designed such that the cutting tool is pivoted into the second position by further retraction of the head section, i.e., after the cutting tool has penetrated and pierced the pipe wall, and the free end of the cutting tool is oriented with the cutting edge facing forward, i.e., extending from the pivot axis in a direction towards the front end of the head section. For this purpose, the cutting tool can have appropriately shaped control surfaces to assist the pivoting movement, such as an inclined or rounded back that comes into contact with the edge of the perforation when the cutting device is retracted and is shaped such that the cutting tool is pivoted forward when the cutting device is retracted.As the cutting tool is pivoted further into the second position, the head is released for withdrawal from the pipe. The continuous pulling motion on the head causes the cutting edge to pivot further forward after penetrating the pipe wall, approaching the longitudinal axis of the head again and retracting from the pipe wall. The cutting device can then be easily pulled out of the pipe. A further advantage is that the cutting and withdrawal processes can transition seamlessly into one another and are triggered by a pulling motion on the head. This significantly simplifies the handling of the cutting device.

[0028] According to a further embodiment of the invention, the cutting tool does not project beyond the outer circumference of the head in the second position. In this embodiment, the cutting tool is fully inserted into the recess in the head when it reaches the second position and lies within the outer circumference of the head. This significantly simplifies the removal of the cutting device from the pipe, as the cutting tool cannot become jammed against the inside of the pipe wall.

[0029] According to a further embodiment of the invention, the cutting device can be designed such that the cutting tool can be pivoted rearward beyond the first position, for example, to facilitate easy insertion of the cutting device into the pipe. Pivoting the cutting device rearward beyond the first position can be accomplished using the adjusting means described above. Furthermore, the recess can also be designed to fully accommodate the cutting tool when the cutting tool is pivoted toward its rear end, so that the cutting tool does not project beyond the outer circumference of the head. Essential to the fundamental concept of the invention is, at a minimum, that the cutting tool can assume the first position described above for the cutting process.

[0030] Another embodiment of the invention further provides that the first position of the cutting tool, necessary for the cutting process, is adjustable. Setting the first position for the cutting process is possible in various ways, for example, by means of an elastic preload element, such as a spring (which will be described later), by means of an adjustable setting mechanism, such as a screw mechanism for extending the cutting tool forward out of the recess, or based on gravity, meaning that the cutting tool pivots out of the receptacle into the first position independently when the cutting device is positioned accordingly. The adjusting means with actuating element described herein represent such an adjustable setting mechanism.

[0031] Another embodiment of the invention provides that the cutting device has a pre-tensioning element designed to pre-tension the cutting tool or cutting edge against the inside of the pipe wall when the head is inserted into the pipe. The pre-tensioning ensures that, after the head is positioned in the pipe, the cutting edge is pressed against the inside of the pipe wall and cuts into the pipe wall as intended. Furthermore, the pre-tensioning element can set the initial position of the cutting tool necessary for the cutting process.

[0032] Another embodiment of the invention provides that the pre-tensioning element is arranged such that it is pre-tensioned when the head is inserted into a pipe and the cutting tool is forced through the inside of the pipe wall in the direction of the longitudinal axis of the head, i.e., inwards or towards the inside of the head. In this embodiment, when the cutting device is inserted into the pipe, the cutting tool comes into contact with the inner wall of the pipe at the pipe opening, provided that a pipe with a sufficiently small inner diameter is selected. The pipe wall presses the cutting tool into the head, thus tensioning the pre-tensioning element. The pre-tensioning element, in turn, exerts a counterforce against the cutting tool and forces the cutting edge against the inside of the pipe wall.

[0033] According to a further embodiment of the invention, the preload element is a spring element, preferably in the form of a spring steel wire extending along the longitudinal axis.

[0034] According to a further embodiment of the invention, the preload element is provided by the actuating element, for example in the form of an elastic connecting rod made of spring steel wire.

[0035] Another embodiment of the invention provides that the cutting device further comprises a pull rod which is preferably detachably connected or connectable to the rear end of the head part. The necessary tensile forces can be introduced into the head part by means of the pull rod.

[0036] The drawbar can, in particular, be a rod that is at least partially threaded and is screwed to the rear end of the head. For this purpose, the drawbar can have a corresponding thread and the head can have a matching mating thread. The connections are specifically designed to transmit tensile forces.

[0037] According to a further embodiment of the invention, the drawbar has means for securing a mechanical, hydraulic and / or pneumatic pulling unit. For this purpose, a thread for attaching a threaded nut or other securing means, for example for a hydraulic pulling unit, can be provided at the end of the drawbar facing away from the head part.

[0038] According to another embodiment of the invention, the cutting tool is a cutting wedge. List of characters

[0039] Further features, advantages, and applications of the invention will also become apparent from the following description of an exemplary embodiment with reference to the drawings. All features described and / or illustrated, individually or in any combination, constitute the subject matter of the invention, irrespective of their compilation in the claims or their cross-references. The drawings show: • Fig. 1 a cutting device according to a first embodiment of the invention in a top view; • Fig. 2 individual components and sections of the cutting device made of Fig. 1; • Fig. 3 another view of the cutting device Fig. 1; • Fig. 4 schematically the insertion of the cutting device Fig. 1 into a pipe; • Fig. 5 schematically the perforation of a pipe with the cutting device made of Fig. 4; • Fig. 6 the front part of a cutting device according to a further embodiment of the invention; • Fig. 7 the rear part of the cutting device Fig. 6.

[0040] Fig. Figure 1 shows a cutting device 1 comprising a head 2 and a pull rod 3. The head 2 has a front end 4 and a rear end 5. The pull rod 3 is screwed to the rear end 5 of the head 2.

[0041] The head section 2 extends along a longitudinal axis 6, which runs through the front end 4 and the rear end 5 of the head section. The drawbar 3 lies in extension of the longitudinal axis 6. An external thread 7 is formed at the rear end of the drawbar 3, onto which a threaded nut 8 is screwed. The threaded nut 8 serves to introduce tensile forces into the cutting device 1.

[0042] Fig. Figure 2 shows the headboard 2 from the Fig. 1, detached from the pull rod 3. The external thread 9 at the front end of the pull rod 3 serves to screw the pull rod 3 to the rear end 5 of the head section 2, as shown in Fig. Figure 1 shows the rear end 5 of the head section 2, which has a corresponding internal thread. A preload element 10 in the form of a spring steel wire is guided in the drawbar 3.

[0043] The head section 2 comprises a cutting tool 11 in the form of a cutting wedge. The cutting tool 11 is pivotally mounted about a pivot axis 12, which runs transversely to the longitudinal axis 6 of the head section 2, by means of a pin. This mounting allows the cutting tool 11 to pivot forward about the pivot axis 12 (direction of arrow 13), i.e., towards the front end 4 of the head section, and back again (direction of arrow 14), i.e., towards the rear end 5 of the head section 2 (pivoting movement shown by a curved double arrow). The front position of the cutting tool 11 is in the Fig. 2 indicated by dashed lines.

[0044] The cutting tool 11 has a free end 15 which has a cutting edge 16.

[0045] Fig. Figure 3 is another representation of the header 2 from the Fig. 1, in which the head part 2 was rotated 90° about its longitudinal axis 6. A groove-like recess 17 is formed in the head part 2, extending in the direction of the longitudinal axis 6. The cutting tool 11 is, as with respect to the Fig. 2 explained, mounted in the recess 17 so that the pivot axis 12 can be pivoted.

[0046] The preload element 10 rests with one end against the cutting tool 11 and serves to exert a preload on the cutting tool 11 such that the cutting edge 16 (see Fig. 2) is pressed outwards, i.e. away from the head part 2. The preloading element 10 is preloaded by the cutting tool 11 in the Fig. 1 or in Fig. In the position shown, the cutting tool is pressed inwards, i.e., pivoted backwards. In operation, this is achieved by pushing the head 2, with the front end 4 leading, into a tube. The tube has a slightly larger inner diameter than the head, but is slightly narrower in the area where the cutting tool protrudes laterally from the head. During insertion, the cutting tool 11 is forced inwards through the inner wall of the tube into the head 2, thus clamping the pre-tensioning element 10. This process is also shown in the Fig. 4 shown.

[0047] Fig. 4 and Fig. Figure 5 schematically shows the operation of the cutting device 1, starting with the insertion and positioning of the cutting device 1 in a pipe ( Fig. 4) until the pipe is perforated ( Fig. 5) The threaded nut made of Fig. Item 1 is not shown. However, the threaded rod 3 is connected to a tensioning unit that is not shown.

[0048] Fig. Figure 4a shows how the cutting device 1, with the head section 2 leading, is inserted forward (arrow 13) into a tube 18. The head section 2 contains the [missing information - likely a reference to the] Fig. The pre-tensioning element 10 described in section 3 is arranged, which is only sketched here as a principle. The cutting tool 11 projects laterally beyond the outer circumference of the head part 2 and, when the head part 2 is inserted into the tube 18, comes into contact with the tube wall 19 and, with further forward movement of the head part 2, pivots inwards (indicated by the curved arrow). This pre-tensions the pre-tensioning element 10.

[0049] Fig. Figure 4b shows how, by further retracting the head 2 into the target position, the cutting tool 11 was pivoted inwards through the inside of the pipe wall 19, i.e., into the recess 17. The preloading element 10 now exerts a preload force on the cutting tool 11 and presses it outwards against the pipe wall 19. After the head has been positioned in the pipe as desired, the cutting process to create a perforation can be initiated. This is explained with regard to the Fig. 5.

[0050] Fig. Figure 5a shows the cutting tool in the position according to Fig. 4b. The cutting tool 11 is here in a first position in which the cutting tool 11 extends beyond the outer circumference of the head part 2 and, under preload, rests with the cutting edge against the pipe wall 19.

[0051] To initiate the perforation process, a rearward pulling force (arrow 14) is introduced into the head 2 via the pull rod 3, which pulls the head 2 backward. This wedges the cutting tool 11 with its cutting edge 16 against the inside of the pipe wall 19 and cuts into the pipe wall.

[0052] When the head section 2 is further withdrawn into the tube 18 (shown in Fig. 5b) The cutting tool 11 cuts deeper into the pipe wall 19 and then pivots forward out of the recess 17 relative to the head part 2 towards the front end 4 of the head part 2 (indicated by the curved arrow). As the free end of the cutting tool with the cutting edge 16 moves increasingly away from the outer circumference or the longitudinal axis of the head part 2 and pivots outwards, the cutting tool 11 penetrates the pipe wall 19 and creates a hole or perforation 20.

[0053] Fig. Figure 5c shows how the cutting tool 11 pivots further towards the front end 4 when the head part 2 is retracted further (arrow 14).

[0054] Fig. Figure 5d shows how the cutting tool 11 re-enters the recess 17 from the front of the pivot axis and retracts from the perforation 20. The cutting tool 11 is moved into the recess 17 by the interplay of the backward movement of the head and the contact of the cutting tool 11 with the edge of the perforation 20.

[0055] In the Fig. In step 5e, the head 2 has been retracted so far that the cutting tool has completely left the perforation 20. This has caused the cutting tool to assume a second position, in which the cutting tool 11 is oriented forward (arrow 13). The head 2 is now free to disengage and can simply be pulled out of the tube axially. The cutting device can then be used in another tube.

[0056] Fig. Figure 6 shows a further embodiment of the invention in three different representations a, b and c.

[0057] This embodiment includes adjusting means with which the position of the cutting tool 11 about the pivot axis 12 can be set before the cutting process. The preload element is in the form of a spring steel wire made of Fig. Item 1 has been removed. The rear end (in the direction of arrow 14) of the cutting tool has been cut off for illustrative purposes. The rear end of the cutting device is in Fig. 7 shown.

[0058] The cutting tool 11 is of the embodiment in Fig. 1 can be pivoted about the pivot axis 12. The cutting tool 11 can be pivoted forwards about the pivot axis 12, i.e., towards the front end 4 of the head 2, in a first pivot direction 21 about the pivot axis 12. Starting from Fig. 6a designates the first pivoting direction, the direction in which the cutting tool pivots during the cutting process described with reference to the first embodiment. The second pivoting direction 22 designates the pivoting direction of the cutting tool 11 about the pivot axis 12, which is opposite to the first pivoting direction 21. The rotary position of the cutting tool 11 about the pivot axis 12 can be adjusted by means of the adjusting means. This is explained with reference to the Fig. 6a and Fig. 6b.

[0059] In Fig. 6a The cutting tool 11 is fully retracted into the head 2 and the cutting edge 16 points to the rear (arrow 14). In this state, the cutting device 1 can be inserted into a pipe without the cutting tool 11, and in particular the cutting edge 16, coming into contact with the inner wall of the pipe. As soon as the cutting device 1 is positioned in the pipe in the target position, the cutting tool 11 is extended by means of the adjusting means. The cutting tool 11 is pivoted in the first pivot direction 21, so that it projects laterally beyond the outer circumference of the head 2 and its cutting edge 16 rests against the inner wall of the pipe. This is comparable to the position of the cutting tool in Fig. 4b.

[0060] To move the cutting tool 11 from the position in Fig. 6a into the position in Fig. To proceed as described in section 6b, the actuating means have an actuating element 23 in the form of a connecting rod. The connecting rod 23 is movably guided in the pull rod 3 relative to the head part 2 along the longitudinal axis 6, i.e., the connecting rod can be moved axially forward (arrow 13) and backward (arrow 14).

[0061] The cutting tool 11 has a control surface 24. At the front end (in the direction of arrow 13) of the connecting rod 23, a magnetic element in the form of a permanent magnet 25 is attached. The permanent magnet 25 is part of a coupling mechanism designed to couple the actuator 23 (connecting rod) to the cutting tool 11. The control surface 24 is designed to interact magnetically with the permanent magnet 25 of the connecting rod 23 according to the principle of a magnetic coupling, so that the control surface 24 adheres to the permanent magnet 25.

[0062] In Fig. 6a The cutting tool 11 is positioned such that the control surface 24 is inclined to the longitudinal axis 6 and thus to the axis of movement of the connecting rod 23. If the connecting rod 23 is moved forward along the longitudinal axis 6 (arrow 13) in the direction of the pivot axis 12, it comes into contact with the control surface 24 of the cutting tool 11. The cutting tool 11 is then magnetically coupled to the actuator 23 (connecting rod). This state is described in Fig. 6a shown.

[0063] If the actuator 23 (connecting rod) is moved from the Fig. As the cutting tool 11 is moved further forward (arrow 13), it is pivoted about the pivot axis 12 in the first pivot direction 21 due to the engagement of the front end of the connecting rod 23 with the control surface 24. The permanent magnet 25 slides along the control surface 24 of the cutting tool, but maintains the magnetic coupling. In the example shown, the cutting tool 11 was moved in this way into the Fig. The position shown in 6b has been swivelled.

[0064] Due to the coupled state of the coupling mechanism between the actuator 23 (connecting rod) and the cutting tool 11, the cutting tool 11 can be axially offset by the connecting rod 23 between the parts in the Fig. 6a and Fig. The positions shown in 6b can be moved back and forth. If the connecting rod 23 is in Fig. When the connecting rod 23 is moved backwards (arrow 14), the actuating forces are transmitted to the cutting tool 11 via the magnetic clutch. The connecting rod thus pulls on the control surface 24 via the magnetic clutch, causing the cutting tool 11 to pivot about the pivot axis 12 in the second pivot direction 22. In the coupled state, the cutting tool 11 can therefore be pivoted in the first pivot direction 21 and in the second pivot direction 22 by corresponding movements of the connecting rod 23 along the longitudinal axis 6. This allows the cutting tool 11 not only to be extended from the head section 2 to assume a first position for the cutting process (see Fig. 6b). The cutting tool can also be retracted if necessary ( Fig. 6a), for example, to abort a cutting operation.

[0065] Fig. Figure 6c shows the position of the cutting tool 11 during a cutting process, the position of the cutting tool shown being comparable to the position of the cutting tool from Fig. 5c, i.e., when the cutting tool moves from the Fig. 6b has wedged itself against the pipe wall and, as a result of the head being pulled back, has pierced it and pivoted forward.

[0066] The coupling mechanism, i.e., in the illustrated example the magnetic coupling, between the cutting tool 11 and the connecting rod 23 is designed to be detachable, so that when the cutting tool 11 wedges itself against the pipe wall and is subsequently pivoted towards the front end 4, the head part 2 is pulled back further (arrow 14), thus automatically decouples itself from the actuator 23 (connecting rod). The cutting process, as described in the illustration, Fig. 5b to Fig. As explained in section 5d, this causes the control surface 24 of the cutting tool 11 to pivot away from the connecting rod 23. This releases the magnetic coupling between the cutting tool 11 and the connecting rod 23. The cutting tool 11 can then pivot freely forward. In the decoupled state, return movements of the adjusting elements do not cause the cutting tool to pivot in the second direction 22. No rotational restoring forces from the magnetic element 25 act on the cutting tool 11; that is, the adjusting elements do not impede the pivoting movement of the cutting tool 11 during the cutting process. While the cutting tool 11 pivots forward in the first direction 21, the connecting rod 23 maintains its position along the longitudinal axis 6.

[0067] Fig. Figure 7 shows the rear end of the cutting device. Fig.6. As already explained, the connecting rod 23 is guided within the drawbar 3 along its longitudinal axis 6 as part of the actuating means. The rear end of the connecting rod 23 is fixedly connected to an actuator in the form of an adjusting screw 26, for example, by crimping, gluing, or soldering. The adjusting screw 26 is part of the actuating means and can also be actuated when the cutting device is inserted into a tube. The adjusting screw 26 is screwed to the drawbar 23 via a threaded connection 27. By rotating the adjusting screw 26 relative to the drawbar 3, the adjusting screw is moved axially along the longitudinal axis 6. Due to the fixed connection between the adjusting screw 26 and the connecting rod 23, the connecting rod 23 is also moved axially along the longitudinal axis 6.Consequently, by actuating and turning the adjusting screw 26 in both directions, the connecting rod 23 can be moved along the longitudinal axis 6 in both longitudinal directions. As explained above, the axial movements of the connecting rod can be converted into rotary movements of the cutting tool to adjust the rotary position of the cutting tool 11. Reference symbol list 1 cutting device 2 Headboard 3 pull rod 4 front end of the headboard 5 rear end of the headboard 6 Longitudinal axis 7 external threads 8 threaded nuts 9 external threads 10 Preload element (spring steel wire) 11 cutting tool (cutting wedge) 12 swivel axes 13 forward 14 backwards 15 free ending 16 cutting edge 17 Exclusion 18 pipe 19 pipe wall 20 Perforation (hole punching) 21 first direction of rotation 22 second direction of rotation 23 Actuator (connecting rod) 24 Control surface 25 Permanent magnet (magnetic element) 26 Actuator means (adjusting screw) 27 Threaded connection

Claims

[1] Cutting device (1) for perforating a tube (18), with a head part (2) which can be inserted into a tube (18) at a front end (4), wherein the head part (2) extends along a longitudinal axis (6) from the front end (4) of the head part (2) to a rear end (5) of the head part (2); and a cutting tool (11) pivotably mounted on the head (2) with a free end (15) having a cutting edge (16), wherein the cutting tool (11) is pivotably mounted about a pivot axis (12) which extends transversely to the longitudinal axis (6) of the head (2), wherein the cutting tool (11) is pivotable from a first position in which the free end (15) of the cutting tool (11) is turned away from the front end (4) of the head (2) towards a second position in the direction of the front end (4) of the head (2), and wherein the cutting tool (11) is designed such thatthat the cutting tool (11) in the first position projects beyond the outer circumference of the head part (2) in such a way that when the head part (2) is inserted into a tube (18) and pulled backward (14) towards the rear end (5) of the head part (2), the cutting tool (11) wedges its cutting edge (16) against the tube wall (19) of the tube (18) and penetrates the tube wall (19), so that by further pulling the head part (2) backward (14) the cutting tool (11) pivots towards the front end (4) to penetrate deeper into the tube wall (19) and pierce the tube wall (19), characterized by, that the cutting device (1) has adjustable adjusting means which are configured to adjust a position of the cutting tool (11) about the pivot axis (12), wherein the adjusting means comprise an adjusting element (23) movable relative to the head part (2) along the longitudinal axis (6) and a coupling mechanism (24, 25) which is configured to couple the adjusting element (23) with the cutting tool (11) in such a way that movements of the adjusting element (23) in different directions along the longitudinal axis (6) are transmitted to the cutting tool (11) in order to pivot the cutting tool (11) in a first pivoting direction (21) towards the front end (4) of the head part (2) to the second position and in a second pivoting direction (22) opposite to the first pivoting direction (21), and wherein the coupling mechanism (24, 25) is designed to be releasable,that the cutting tool (11) can decouple itself from the actuator (23) by further retracting the head part (2) backwards (14) when it wedges itself against the pipe wall (19) and is subsequently pivoted towards the front end (4). [2] Cutting device (1) according to claim 1, wherein the releasable coupling mechanism comprises positive locking means and / or force locking means (25). [3] Cutting device (1) according to one of claims 1 or 2, wherein the releasable coupling mechanism (24, 25) comprises a magnetic coupling. [4] Cutting device (1) according to one of claims 1 to 3, wherein the cutting tool (11) comprises a control surface (24) for engaging a front end of the actuating element (23), wherein the control surface (24) is designed such that a movement of the actuating element (23) in the direction of the pivot axis (12) pivots the cutting tool (11) in the direction of the second position. [5] Cutting device (1) according to one of claims 1 to 4, wherein the adjusting means comprise actuator means (26), preferably in the form of an adjusting screw, to actuate the adjusting means in a state of the cutting device (1) inserted into a tube (18). [6] Cutting device (1) according to one of the preceding claims, wherein the cutting device (1) is designed such that the cutting tool (11) is pivoted into the second position by further retraction of the head part (2) and the free end (15) of the cutting tool (11) is oriented forward (13) so that the cutting tool (11) detaches from the pipe wall (19) and releases the head part (2) to move out of the pipe (18). [7] Cutting device (1) according to claim 6, wherein the cutting tool (11) does not extend beyond the outer circumference of the head part (2) in the second position. [8] Cutting device (1) according to one of the preceding claims, wherein the cutting device (1) has a pre-tensioning element (10) designed to pre-tension the cutting tool (11) against the pipe wall (19). [9] Cutting device (1) according to claim 8 and one of claims 1 to 5, wherein the preload element is formed by the actuating element (23).

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