TOOL UNIT

Abstract

In a tool unit comprising a tool holder and at least one tool, the tool holder being designed for holding the tool and for guided displacement of the tool in an axial direction from a rest position to a working position and back, the tool holder comprises a control region with a control profile, and wherein a control pin is designed to interact with regions offset in the axial direction in the control profile.

Claims

1. A tool unit comprising a tool holder and at least one tool, the tool holder being designed for holding the at least one tool and for guided displacement of the at least one tool in an axial direction from a rest position to a working position and back, characterized in that the tool holder comprises a control region with a control profile, and wherein a control pin is designed to interact with regions offset in the axial direction in the control profile.

2. The tool unit according to claim 1, characterized in that the tool holder comprises a base body and at least one guide element arranged thereon for moving the at least one tool in the tool holder, wherein, in a wall of the at least one guide element, at least one control groove for a control pin on the at least one tool for engagement in the at least one control groove is formed, the at least one control groove comprising a groove control profile running along a circumferential direction of the wall, the groove control profile comprising at least two regions offset in the axial direction, and wherein a drive means is provided in the tool holder for rotating the at least one guide element in the tool holder.

3. The tool unit according to claim 2, characterized in that the at least one control groove comprises an axially directed inlet section for the control pin, wherein said inlet section opens at an edge of the wall.

4. The tool unit according to claim 2, characterized in that the drive means is formed by a belt which runs around the at least one guide element and which engages with the at least one guide element.

5. The tool unit according to claim 2, characterized in that the drive means is formed by a driven gearwheel which is toothed with the at least one guide element.

6. The tool unit according to claim 2, characterized in that the tool holder comprises a plurality of guide elements and that the drive means is designed for synchronously rotating the plurality of guide elements, wherein the plurality of guide elements, with respect to the regions of the control grooves that are offset in the axial direction relative to the drive means, is received in the tool holder offset in the circumferential direction of the plurality of guide elements.

7. The tool unit according to claim 6, characterized in that the drive means is in engagement with a first guide element of the plurality of guide elements and that at least one further guide element of the plurality of guide elements is in engagement with the first guide element.

8. The tool unit according to claim 2, characterized in that three identical control grooves are arranged in the at least one guide element and offset by 120° each, in a circumferential direction of the at least one guide element.

9. The tool unit according to claim 2, characterized in that a resilient stop is formed between the at least one tool and the at least one guide element.

10. The tool unit according to claim 1, characterized in that the control profile is designed as a profiled hole on the tool holder and the profiled hole cooperates with a rotatable profiled control pin on a support element of the tool unit.

11. The tool unit according to claim 10, characterized in that the support element comprises a plurality of control pins which are driven by a drive means for synchronous rotation, wherein a tool holder having the profiled hole each cooperates with a control pin.

12. The tool unit according to claim 10, characterized in that the control pin is resiliently mounted along its axis of rotation.

13. A 3D positioning device comprising a tool unit according to claim 1.

Description

[0023] The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawing. In the drawings

[0024] FIG. 1 is a perspective view of a tool, a guide element and an anti-twist device for the tool,

[0025] FIG. 2 is a perspective view of a tool holder with three guide elements,

[0026] FIG. 3 is a schematic representation of three control grooves for three guide elements or tools,

[0027] FIG. 4 is an illustration of a drive means for three guide elements,

[0028] FIG. 5 is a perspective view of an alternative drive means for three guide elements and

[0029] FIG. 6 shows a perspective illustration of an alternative embodiment of a tool unit according to the invention.

[0030] In FIG. 1, a tool 1 is designed as a working head or print head 1 for a 3D printer. Filament (not shown) is fed to the print head 1 at a proximal end 2 and the filament is melted in the printhead 1 and released and solidified at the distal end 3 (“hot end”) to build a workpiece in an additive manufacturing process. The tool 1 can also be designed as a cutting tool, for example a CNC milling machine, but this is not shown in the figures.

[0031] The print head 1 has three control pins 4, which are arranged around the circumference of the print head 1 and are offset by 120°. The print head 1 can now enter the guide element 9 in the axial direction, which is symbolized by the double arrow 5, by inserting the control pins 4 into the inlet section 6 of the control groove 7 in the wall 8 of the guide element 9. When the print head 1 is inserted into the guide element 9 and with its control pin 4 into the control groove 7, it is secured against rotation in the guide element 9 by the ribs 10, which interact with corresponding recesses 10′ on the anti-rotation device 11, so that the guide element 9 is rotated by the action of the control profile 12 of the control groove 7 to displace the print head 1 or tool 1 in the axial direction 5. The reason for this is that the control profile 12 has areas 13′ and 13″ which are offset in the axial direction and which correspond to different axial positions of the tool 1 in the sense of the double arrow 5. By turning the guide element 9, the control pins 4 of the tool 1 or of the print head 1 pass through the control profile 12 and the print head 1 is pushed forwards or backwards according to the axial positions of the different regions of the control profile 12.

[0032] FIG. 2 now shows that the invention can be used in a particularly advantageous manner for moving a plurality of tools or print heads. For this purpose, several guide elements 9, 9′ and 9″ are arranged in a common tool holder 14. The guide elements 9, 9′ and 9″ have mutually different control profiles 12, 12′ and 12″, which with respect to the regions 13′, 13″ of the control grooves 7, 7′, 7″ which are offset in the axial direction with regard to a drive means, which is received in the tool holder 14, are each received in the tool holder 14 offset in the circumferential direction (symbolized by the double arrows 15) of the guide elements 9, 9′ and 9″. The guide elements 9, 9′ and 9″ are driven by the drive means for common and synchronous rotation and the control profiles 12, 12′ and 12″ are oriented to one another in such a way that, depending on the respective rotational position of the drive means, only one tool (not shown in FIG. 2) is in an axially advanced working position, while the other tools are either in a retracted rest position or, if the control pin(s) of the tool is/are aligned with the inlet sections 6, in a release position. Reference numeral 16 designates a drive with a motor and a gear for the drive means.

[0033] The fact that has just been described can be better understood when looking at FIG. 3. In a first rotational position or rotational position A of the guide elements 9, 9′ and 9″ in the tool holder, the control pin 4 of a first print head is located in an axially advanced region of the control groove 7. The corresponding print head is thus in a working position. At the same time, the control pin 4′ of a second print head is located in an axially retracted region of the control groove 7′ and the control pin 4″ of a third print head is aligned with the inlet section 6 of the guide element 9″ and is there also in an axially retracted region of the control groove 7″.

[0034] In a second rotational position or rotational position B of the guide elements 9, 9′ and 9″ in the tool holder, the control pins 4 and 4″ of the first and third printhead are located in an axially retracted region of the control grooves 7 and 7″ and the corresponding print heads are thus in a rest position. At the same time, however, the control pin 4′ of the second print head is located in an axially advanced region of the control groove 7′ and the print head is thus in a working position.

[0035] In a third rotational position or rotational position C of the guide elements 9, 9′ and 9″ in the tool holder, the control pins 4 and 4′ are located in an axially retracted region of the control grooves 7 and 7′ and the corresponding print heads are thus in a rest position. At the same time, however, the control pin 4″ of the third print head is located in an axially advanced region of the control groove 7″ and the print head is thus in a working position.

[0036] The further exemplary rotational positions not explicitly designated and shown in dashed lines in FIG. 3 are transition positions or are used to remove or insert print heads. The control grooves 7, 7′ and 7″ in FIG. 3 do not necessarily correspond to those that can be seen in the preceding figures and an abundance of different configurations of the control profiles 12, 12′ and 12″ are conceivable.

[0037] In FIG. 4, the drive means is implemented as a toothed belt 23 with inwardly directed teeth. The toothed belt 23 is toothed with the guide elements 9, 9′ and 9″, so that a rotation of the toothed belt in the direction of the arrow 24 leads to a synchronous rotation of the guide elements 9, 9′ and 9″ in the same direction, since with the embodiment shown in FIG. 4 the guide elements 9, 9′ and 9″ are not directly interlocked with one another but are only connected to one another via the toothed belt 23.

[0038] Alternatively, the drive means can be formed by a driven gearwheel (not shown) which meshes with a first guide element 9. FIG. 5 relates to this variant and it can be seen that the first guide element 9 in turn engages with the further guide elements 9′ and 9″. When the first guide element 9 rotates in the direction of the arrow 25, the further guide elements 9′ and 9″ perform an opposite and synchronous rotation in the direction of the arrows 26.

[0039] FIG. 6 shows how a tool, for example a print head, can be fixed to a support element 17 in order to allow the axial movement to be achieved with the present invention. A rotatable control pin 18′ on the support element 17 interacts with a corresponding profiled hole 18″ in an alternative tool holder 19. The tool holder 19 is pushed with the profiled hole 18″ over the rotatable control pin 18′. Upon rotation of the rotatable control pin 18′ in the direction of the double arrow 20, the profile in the profiled hole 18″ is scanned by the eccentric control bolt 18′, so that a displacement of the tool holder 19 and thus a tool attached to it takes place in the direction of the double arrow 5 and thus in the axial direction. The pins 21 engage in the corresponding elongated holes 21′ or in the groove 21″, which allows movement in the axial direction 5 for moving the print head or generally the tool. Bearing balls 22 press against corresponding grooves 22′ and can also be displaced in the same in the direction of double arrow 5.