Device and method for welding hard material elements onto teeth of a saw blade

Abstract

The invention relates to a device (2) for welding hard material elements (4) onto teeth (6) of a saw blade (8), comprising a saw blade feed device (12) for moving the saw blade (8) in a feed direction (14), such that a tooth (6a) of the saw blade (8) can be brought into a target position (16) in a working region (10) of the device (2), comprising a first centering device (30) for centering the saw blade (8) transversely to the feed direction (14), comprising a second centering device (32) for centering a respective hard material element (4) transversely to the feed direction (14), comprising a resistance welding device (24) having a welding electrode (26) that can be deployed into and withdrawn from the working region (10), comprising a supply device (28) for supplying and transferring a respective hard material element (4) to the welding electrode (26), and it being possible for the welding electrode (26) to be deployed in such a way that the hard material element (4) can be brought toward the tooth (6a) to abut the tooth (6a). According to the invention, the hard material element (4) can be centered relative to the centered and fixed saw blade (8) by means of the second centering device (32), and the first and second centering device (30) are provided in a common assembly (38), such that the centering of the saw blade (8) by the first centering device (32) predetermines a centering position for the subsequent centering of the hard material element (4) by the second centering device (32).

Claims

1. Device (2) for welding hard material elements (4) onto teeth (6) of a saw blade (8), including a band or circular saw blade, comprising: a saw blade feed device (12) for moving the saw blade (8) in a feed direction (14), such that a respective intended tooth (6a) of the saw blade (8) can be brought into a target position (16) in a working region (10) of the device (2), a first centering device (30) for centering the saw blade (8) transversely to the feed direction (14) and for fixing the saw blade (8) while a respective hard material element (4) is welded on, a supply device (28) for supplying the respective hard material element (4), a second centering device (32) for centering the respective hard material element (4) transversely to the feed direction (14) before the welding, a resistance welding device (24) having a welding electrode (26) that can be deployed into the working region (10) and withdrawn from the working region (10), the supply device (28) being configured to supply and transfer the respective hard material element (4) to the welding electrode (26), and deploy the welding electrode (26) with the respective hard material element (4) transferred thereto into the working region (10) so that the respective hard material element (4) can be brought toward the respective intended tooth (6a) in the target position (16) to abut the respective intended tooth (6a), characterized in that the second centering device (32) is configured to center the respective hard material element (4) abutting the respective intended tooth (6a) relative to the centering of the fixed saw blade (8), and the first centering device (30) and the second centering device (32) are provided in a common assembly (38), such that the centering of the saw blade (8) by the first centering device (30) predetermines a centering position for a subsequent centering of the respective hard material element (4) by the second centering device (32).

2. Device (2) according to claim 1, characterized in that the first centering device (30) for centering and fixing the saw blade (8) comprises a first gripper arrangement (40) having first gripper jaws (44a, 44b) configured to move toward or away from one another transversely or obliquely to the feed direction (14).

3. Device (2) according to claim 2, characterized in that the first gripper arrangement (40) comprises a pull-down mechanism, so that the saw blade (8) that has a band back facing away from the teeth (6), is brought into abutment with a support surface during the centering and fixing of the saw blade (8).

4. Device (2) according to claim 1, characterized in that the common assembly (38) comprises at least one double-acting cylinder (60).

5. Device (2) according to claim 1, characterized in that the second centering device (32) for centering the respective hard material element (4) before the welding comprises a second gripper arrangement (52) having second gripper jaws (54a, 54b) configured to move toward or away from one another transversely or obliquely to the feed direction (14).

6. Device (2) according to claim 5, characterized in that the second gripper jaws (54a, 54b) are configured to guide on the first gripper jaws (44a, 44b).

7. Device (2) according to claim 5, characterized in that either the first gripper jaws (44a, 44b), or the second gripper jaws (54a, 54b), or both, is configured to move toward or away from one another via wedge hook or wedge surface gear mechanisms (64a, 64b).

8. Device (2) according to claim 7, characterized in that the wedge hook or wedge surface gear mechanisms (64a, 64b) comprise wedge slides (66a, 66b) which are guided in the first gripper jaws (44a, 44b) of the first centering device (30).

9. Device (2) according to claim 1, characterized in that the device comprises a measuring sensor device (34) configured to interact with the saw blade feed device (12), such that a respective intended tooth (6) of the saw blade (8) can be brought into the target position (16) in the working region (10) by means of the saw blade feed device (12) and using the measuring sensor device (34).

10. Device (2) according to claim 9, characterized in that the measuring sensor device (34) is configured to come into contact with a corresponding tooth (6) of the saw blade (8) when the saw blade (8) is moved in the feed direction (14).

11. Device (2) according to claim 10, characterized in that, when the saw blade (8) is moved in the feed direction (14), the measuring sensor device (34) is configured to come into contact with the corresponding tooth (6) of the saw blade (8) that is being moved to the target position (16).

12. Device (2) according to claim 11, characterized in that the measuring sensor device (34) is configured to come into contact with the corresponding tooth (6) close to the region of the corresponding tooth (6) to which the respective hard material element (4) is to be welded.

13. Device (2) according to claim 9, characterized in that the measuring sensor device (34) is configured to insert into and withdraw from a tooth gap transversely to the feed direction (14).

14. Device (2) according to claim 9, characterized in that the measuring sensor device (34) is configured to deflect in the feed direction (14) while a measuring operation is being carried out.

15. Device (2) according to claim 1, characterized in that the device comprises a monitoring and detecting device configured for monitoring and detecting the welding action of the device.

16. Device (2) according to claim 15, characterized in that, when the second gripper jaws (54a, 54b) are reset, the monitoring and detecting device is configured to make an uncovered direct optical and/or thermal detection.

17. Device (2) according to claim 1, characterized in that the welding electrode (26) is configured to magnetically hold the respective hard material element (4) transferred thereto.

18. Method for welding hard material elements (4) onto teeth (6) of a saw blade (8) using a device (2) according to claim 1, characterized in that the method comprises the following steps: supplying the saw blade (8) in a feed direction (14) by means of the saw blade feed device (12); bringing a respective intended tooth (6a) of the saw blade (8) into a target position (16) in a working region (10) of the device (2); centering the saw blade (8) by means of the first centering device (30) transversely to the feed direction (14); fixing the saw blade by means of the first centering device (30); supplying and transferring the respective hard material element (4) to a welding electrode (26) by means of the supply device (28), deploying the welding electrode (26) together with the respective hard material element (4) transferred thereto into the working region (10); centering the respective hard material element (4) brought into the working region by means of the second centering device (32) transversely to the feed direction before the welding, welding the respective hard material element (4) onto the tooth (6a) in the target position (16) in the working region; withdrawing the welding electrode (26) from the working region (10); characterized in that a centering position for the centering of the respective hard material element (4) by the second centering device (32) is predetermined by the centering of the saw blade (8) by the first centering device (30), such that, when centering the respective hard material element (4) transversely to the feed direction (14), the respective hard material (4) element is centered relative to the previously centered and fixed saw blade (8).

19. Device (2) according to claim 2, characterized in that the common assembly (38) comprises at least one double-acting cylinder (60).

20. Device (2) according to claim 2, characterized in that the second centering device (32) for centering the respective hard material element (4) before the welding comprises a second gripper arrangement (52) having second gripper jaws (54a, 54b) configured to move toward or away from one another transversely or obliquely to the feed direction (14).

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1a is a perspective view of the device according to the invention with a saw blade;

(2) FIG. 1b is a schematic view of the device according to the invention according to FIG. 1a with a saw blade;

(3) FIG. 2 shows a detail of the device according to the invention according to FIG. 1a without a saw blade;

(4) FIGS. 3a to 3d show different views of an assembly of the device according to the invention according to FIG. 1a, and

(5) FIG. 4 shows a further detail of the device according to the invention according to FIG. 1a with a saw blade.

DETAILED DESCRIPTION OF THE BEST MODE OF THE INVENTION

(6) FIGS. 1a and 1b schematically show a perspective view of the device according to the invention, designated as a whole by reference number 2, for welding hard material elements 4 onto teeth 6 of a saw blade 8. In the embodiment shown, the saw blade 8 is a band saw blade. The invention can also be applied to circular saw blades.

(7) The hard material elements 4 are welded onto the teeth 6 of the saw blade 8 in a working region 10 of the device 2. For this purpose, the saw blade 8 is moved in the feed direction 14 by means of a saw blade feed device 12, such that a respective intended tooth 6a of the saw blade 8 can be brought into a target position 16 in the working region 10 of the device 2.

(8) According to the embodiment shown, the saw blade feed device 12 comprises gripping or clamping devices 18 for grasping the saw blade 8, which are mounted on feed carriages 20. The feed carriages 20 can be moved, for example by means of a drive, in the direction of the double arrow 22 in parallel with the feed direction 14. The drive is preferably an electric linear drive.

(9) For welding the hard material elements 4 onto the teeth 6 of the saw blade 8, the device 2 comprises a resistance welding device 24 having a welding electrode 26 which can be deployed into the working region 10 and withdrawn from the working region 10. Using a supply device 28, a respective hard material element 4 is supplied to the welding electrode 26 and transferred thereto. The welding electrode 26 with the hard material element 4 transferred thereto is deployed into the working region 10 of the device 2, and the hard material element 4 is brought toward the tooth 6a, in the target position 16, of the saw blade 4, namely until abutment with the tooth 6a.

(10) Using a first centering device 30, before the welding action the saw blade 8 is centered transversely to the feed direction 14 and fixed in the centered position. A second centering device 32 is used to center the respective hard material element 4 transversely to the feed direction 14 before welding onto the respective intended tooth 6a, in the target position, of the saw blade 8. The mode of operation and the structure of the first and the second centering device 30, 32 are explained below with reference to FIGS. 2 and 3a to 3d. After the welding action has ended, the saw blade 8 is moved further in the feed direction 14 by means of the saw blade feed device 12, so that a subsequent tooth 6b can be brought into the target position 16.

(11) FIG. 2 shows a detail or a partial view of the device 2 according to the invention according to FIG. 1; further components which are not of immediate interest are omitted for better understanding. The detail shown shows the working region 10, the first centering device 30, the second centering device 32 and a measuring sensor device 34. By means of the measuring sensor device 34, a respective intended tooth 6a of the saw blade 8 is brought into the target position 16 or it is ensured that a respective intended tooth 6a of the saw blade is in the target position. For this purpose, the measuring sensor device 34 can be inserted into and withdrawn from a tooth gap of the saw blade 8 located in the working region 10. When the saw blade 8 is moved by the saw blade feed device 12 in the feed direction 14, the measuring sensor device 34 positioned in the working region comes into contact with a tooth 6 of the saw blade 8 and a stylus 36 of the measuring sensor device 34 is deflected in the feed direction 14. The measuring sensor device 34 further comprises a sensor (not shown) which detects the deflection of the stylus 36. The deflection of the stylus 36 of the measuring sensor device 34 can be used to determine whether the respective intended tooth 6a of the saw blade 8 is in the target position 16. When the target position 16 is reached, the feed of the saw blade 8 by the saw blade feed device 12 is interrupted, and the saw blade 8 is centered and fixed transversely to the feed direction 14 by the first centering device 30, preferably until the end of the upcoming welding action.

(12) FIGS. 2 and 3a to 3c show an assembly that is designated as a whole by reference number 38. The assembly 38 comprises the first centering device 30 for centering the saw blade 8 and the second centering device 32 for centering a respective hard material element 4.

(13) The first centering device 30 comprises a first gripper arrangement 40 having first gripper jaws 44a, 44b that can be moved toward or away from one another transversely to the feed direction 14 in the direction of the double arrow 42, for gripping the saw blade 8. The gripping movement of the first gripper jaws 44a, 44b is converted, for example, from an actuating movement of an in particular double-acting cylinder via a wedge hook gear mechanism into a movement in the direction of the double arrow 42.

(14) According to the embodiment shown here, the gripper jaws 44a, 44b comprise base jaws 46a, 46b and electrically conductive gripper jaw inserts 48a, 48b. The gripper jaw inserts 48a, 48b contact the saw blade 8 during the welding action. To derive the welding current, the gripper jaw inserts 48a, 48b are connected via electrical terminals 50 to electrical lines via which the welding current is conducted.

(15) The first centering device 30 further comprises a pull-down mechanism. Via the pull-down mechanism, during the gripping and fixing by means of the first gripper jaws 44a, 44b the saw blade 8 is brought into abutment with a support surface 51, which is only shown schematically in FIG. 1b and is located between the first gripper jaws 44a, 44b.

(16) The second centering device 32 comprises a second gripper arrangement 52 having second gripper jaws 54a, 54b, the second gripper jaws being guided in the gripper jaws 44a, 44b.

(17) According to the embodiment shown here, the gripper jaws 54a, 54b can be moved toward or away from one another obliquely to the feed direction 14. According to the embodiment shown here, the second gripper jaws 54a, 54b comprise second base jaws 56a, 56b and gripper fingers 58a, 58b for grasping and centering the hard material element 4.

(18) According to the embodiment shown here, the second centering device 32 comprises a double-acting cylinder 60. An actuating movement caused by the double-acting cylinder 60 is transmitted to wedge hook gear mechanisms 64a, 64 via a cylinder bridge 62. The wedge hook gear mechanisms 64a, 64b convert the actuating movement of the double-acting cylinder 60 into the gripping movement of the second gripper jaws 54a, 54b, in the present example obliquely to the feed direction 14, but in particular and preferably orthogonally to the actuating movement of the double-acting cylinder 60. It would also be conceivable for the actuating movement to be generated by drive means other than a double-acting cylinder.

(19) It can be seen from FIGS. 3a to 3c that the second gripper jaws 54a, 54b of the second gripper arrangement 52 are guided on the first gripper jaws 44a, 44b of the first gripper arrangement 40. FIG. 3d shows a halved sectional view of the assembly 38. A wedge slide 66a of the wedge hook gear mechanism 64a of the second gripper arrangement 52 is guided in the first gripper jaws 44a of the first gripper arrangement 40. In this way, the second centering device 32 is centered relative to the first centering device 30, transversely to the feed direction. The centering of the saw blade 8 by the first centering device 30 thus simultaneously predetermines a centering position for the centering of the hard material element 4 by the second centering device 32.

(20) FIG. 4 shows a detail of the device 2 according to the invention according to FIG. 1 with a saw blade 8 and a hard material element in the target position. The detail shown shows the working region 10 of the device 2. The tooth 6a of the saw blade 8 is in the target position 16. The saw blade 8 is received between the gripper jaw inserts 48a, 48b of the first gripper arrangement 40 of the first centering device 30 and centered and fixed transversely to the feed direction 14. The hard material element 4a is arranged between the gripper fingers 58a, 58b of the second gripper arrangement 52 of the second centering device 32. The welding electrode 26 of the resistance welding device is shown withdrawn from the working region for a better representation of the hard material element. In normal operation, the welding electrode 26 contacts the hard material element and holds it against the tooth in question, while the gripper fingers 58a, 58b border the hard material element on both sides and thus center it with respect to the saw blade plane. After this centering has been carried out, the gripper fingers 58a, 58b move back and the welding action is then carried out.