Connecting Element, Method And Apparatus For Its Production

Abstract

The invention relates to a method for producing a rod- or pipe-shaped connecting element (100, 100) having an end face (106) from a semi-finished connecting element (102) made of metal, in particular of a drill or chisel insertion end which is secured in an axially movable manner in a chuck of a hammer drill, a semi-finished connecting element (102) is provided, characterized in that at least one radially movable forming body (206) guided in the recesses (204) of a die (202) for forming at least one longitudinal groove (122, 124) closed on both sides in the semi-finished connecting element (102) has a smaller longitudinal extension (LR) than a planned length (L) of the longitudinal groove (122, 124) and that the forming of the at least one longitudinal groove (122, 124) closed on both sides in the semi-finished connecting element (102) is performed by radially applying the at least one forming body (206) and by subsequently axially shifting the semi-finished connecting element (102) in a longitudinal die opening (214) of the die (202).

Claims

1. A method for producing a rod-shaped connecting element or pipe-shaped connecting element, which has an end face, from a semi-finished connecting element made of metal, in particular, a drill or chisel insertion end which is secured in an axially movable manner in a chuck of a hammer drill, the method comprising: providing a semi-finished connecting element; providing at least one radially movable forming body configured to be guided in at least one recess of a die for forming at least one longitudinal groove closed on both sides in the semi-finished connecting element, said at least one radially movable forming body having a smaller longitudinal extension than a planned length of the longitudinal groove; and, forming at least one longitudinal groove closed on both sides in the semi-finished connecting element by radially applying the at least one radially movable forming body and subsequent axial shifting of the semi-finished connecting element in a longitudinal die opening of the die.

2. The method according to claim 1, wherein the longitudinal extension of the at least one radially movable forming body has one to three times a width of the at least one longitudinal groove closed on both sides.

3. The method according to claim 1, wherein the die has an interior contour corresponding to at least one rotary entrainment surface of connecting element and that the at least one rotary entrainment surface is formed by forced insertion of the semi-finished connecting element in the die in the direction of a longitudinal axis of the die and that the at least one longitudinal groove closed on both sides is embossed by radially applying the at least one radially movable forming body movable in the die and subsequent axial movement in the direction of the longitudinal axis of the die.

4. The method according to claim 3, wherein the embossing of the at least one longitudinal groove closed on both sides is performed during the forming of the at least one rotary entrainment surface, by the at least one radially movable forming body being axially offset relative to a longitudinal axis of the die from a front end of at least one forming element arranged in the die for forming the at least one rotary entrainment surface.

5. The method according to claim 3, wherein the embossing of the at least one longitudinal groove closed on both sides begins upon completion of the forming of the at least one rotary entrainment surface by radially applying the at least one movable forming body and is continued and/or completed by expelling the connecting element from the longitudinal die opening under an axially acting force.

6. The method according to claim 3, wherein the semi-finished connecting element is pipe-shaped having an interior pipe cavity with an interior pipe diameter in the area of at least one planned rotary entrainment surface and at least one planned longitudinal groove closed on both sides, wherein the interior pipe diameter is reduced or closed by forming the at least one rotary entrainment surface.

7. The method according to claim 1, characterized in that the die is divided at least once in its longitudinal direction thereby forming at least two die parts and that the die parts are at a slight distance from each other proportionate to a diameter of the connecting element immediately before ejection.

8. A method of providing a semi-finished connecting element, in particular a drill or chisel semi-finished product, with at least one rotary entrainment surface and/or with at least one longitudinal groove closed on both sides, comprising the steps of: providing a semi-finished connecting element; providing at least one radially movable forming body configured to be guided in at least one recess of a die for forming at least one longitudinal groove closed on both sides in the semi-finished connecting element, the at least one radially movable forming body having a smaller longitudinal extension than a planned length of the longitudinal groove so that the at least one longitudinal groove closed on both sides can be formed in the semi-finished connecting element by radially applying the at least one radially movable forming body and subsequently axially shifting the semi-finished connecting element in a longitudinal die opening of the die.

9. The method of claim 8, including the further step of forming at least one longitudinal groove closed on both ends by radially applying the at least one radially movable forming body and subsequently axially shifting the semi-finished connecting element in a longitudinal die opening of the die.

10. An apparatus for producing a connecting element from a semi-finished connecting element, in particular a drill or chisel insertion end secured in an axially movable manner in a chuck of a hammer drill, comprising: a die, at least one radially movable forming body guided in at least one recess of the die for forming at least one longitudinal groove closed on both sides in the semi-finished connecting element, which the at least one radially movable forming body has a smaller longitudinal extension than a planned length of the longitudinal groove, and an extrusion punch, acting in a longitudinal die direction of the die by which the semi-finished connecting element is slidable in the die.

11. The apparatus according to claim 10, further comprising: an additional die and an extrusion punch acting in a longitudinal die opening of the die and/or the additional die for forming at least one rotary entrainment surface in the semi-finished connecting element.

12. The apparatus according to claim 10, wherein a first extrusion punch arranged on one side of the longitudinal die opening for forming the at least one rotary entrainment surface in the semi-finished connecting element upon insertion in the die, and a second extrusion punch on an ejection side located opposite the first extrusion punch for forming the at least one longitudinal groove closed on both sides in the semi-finished connecting element upon expulsion from the die.

13. The apparatus according to claim 10, wherein outside of the die and approximately perpendicular to the longitudinal die opening at least one wedge is arranged that is configured to press on the at least one radially movable forming body for embossing the at least one longitudinal groove closed on both sides on the semi-finished connecting element.

14. The apparatus according to claim 13, wherein the at least one wedge is attached as an interior cam surface in a bushing rotatably supported concentrically to the die and, by rotating the bushing, the force for forming the at least one longitudinal groove closed on both sides is applied to the at least one radially movable forming body.

15. The method according to claim 2, wherein the die has an interior contour corresponding to at least one rotary entrainment surface of connecting element and that the at least one rotary entrainment surface is formed by forced insertion of the semi-finished connecting element in the die in the direction of a longitudinal axis of the die and that the at least one longitudinal groove closed on both sides is embossed by radially applying the at least one radially movable forming body movable in the die and subsequent axial movement in the direction of the longitudinal axis of the die.

16. The method according to claim 3, wherein the semi-finished connecting element is pipe-shaped having an interior pipe cavity with an interior pipe diameter in the area of at least one planned rotary entrainment surface and at least one planned longitudinal groove closed on both sides, wherein the interior pipe diameter is reduced or closed by forming one of (i) the at least one longitudinal groove closed on both sides; and (ii) the at least one rotary entrainment surface; and prior to reducing or closing the interior pipe diameter, inserting an interior pin into the inner pipe cavity, the interior pin having at least one recessed portion allowing for formation of the one of the at least one longitudinal groove closed on both sides and the at least one rotary entrainment surface.

17. The method according to claim 3, wherein the embossing of the at least one longitudinal groove closed on both sides is performed during the forming of the at least one rotary entrainment surface.

18. The method according to claim 1, characterized in that the die is divided at least once in its longitudinal direction thereby forming at least two die parts and that the die parts are at a slight distance from each other proportionate to a diameter of the connecting element during ejection.

Description

[0021] Additional preferred embodiments of the invention are listed in the dependent claims.

[0022] Below, preferred embodiments of the invention are described based on the drawings. Parts or method steps that are identical or have identical functions are identified by the same reference symbols. The drawings show the following:

[0023] FIG. 1 shows a semi-finished connecting element for use in the methods and/or apparatuses according to the invention in a perspective view and a side view;

[0024] FIG. 2 shows a perspective view of a connecting element according to a first embodiment of the invention;

[0025] FIG. 3 shows a perspective view of a connecting element according to a second embodiment of the invention;

[0026] FIG. 4 shows the detail view A of FIG. 2;

[0027] FIG. 5 shows a partial top view of the connecting element of FIG. 2;

[0028] FIG. 6 shows a sectional view according to the sectional line C-C shown in FIG. 5;

[0029] FIG. 7 shows a sectional view according to the sectional line B-B shown in FIG. 5;

[0030] FIG. 8 shows the detail view A of the second embodiment of the connecting element according to FIG. 3;

[0031] FIG. 9 shows a partial top view of the connecting element of the second embodiment according to FIG. 3;

[0032] FIG. 10 shows a sectional view according to the sectional line B-B shown in FIG. 9;

[0033] FIG. 11 shows a sectional view according to the sectional line C-C shown in FIG. 9;

[0034] FIG. 12 shows a first embodiment of an apparatus according to the invention for producing a connecting element from a semi-finished connecting element;

[0035] FIG. 13 shows the embodiment of FIG. 12 at a later point in time;

[0036] FIG. 14 shows a cross-section of a third embodiment of an apparatus according to the invention for producing a connecting element from a semi-finished connecting element;

[0037] FIG. 15 shows a longitudinal section of the embodiment of FIG. 14;

[0038] FIG. 16 shows a perspective view of the embodiment of FIG. 14;

[0039] FIG. 17 shows a pipe-shaped semi-finished connecting element for use in the methods and/or apparatuses according to the invention in a perspective view;

[0040] FIG. 18 shows a cross-sectional view of an interior pin taken along a longitudinal axis of an interior pin having a cylindrical shape;

[0041] FIG. 19 shows a portion of a right end of the interior pin having an annular recess;

[0042] FIG. 20 is a schematic view of a die having two halves or parts; and,

[0043] FIG. 21 is a schematic view of a second embodiment of an apparatus according to the invention for producing a connecting element from a semi-finished connecting element having first and second dies and first and second extrusion punches.

[0044] FIG. 1 shows a semi-finished connecting element 102 for use in the methods and/or apparatuses according to the invention in a perspective view and in a side view. The semi-finished connecting element 102 shown in FIG. 1 is made of metal. The semi-finished connecting element 102 is overall embodied as a cylindrical rod. Alternatively, as shown in FIG. 17, the semi-finished connecting element can be a cylindrical piped-shape connecting element 102 having a hollow interior cavity 180 extending the length or substantially the length of connecting element 102. The semi-finished product 102 has a section 103 having a smaller diameter, always shown on the left in FIG. 1, and a section 104, always shown on the right in FIG. 1, which has, when compared to the diameter of the section 103, a diameter that is roughly twice as large, wherein the difference in diameters between the sections 103 and 104 are irrelevant for the present invention. In addition, the semi-finished product 102 has at its side facing away from the thinner section 103 an end face 106. FIG. 1 shows the raw state 110 of the semi-finished product 102 before the embossing of a longitudinal groove or a rotary entrainment surface in the section 104. The dashed line 136 visible in FIG. 1 in the side view of the semi-finished product 102 shows the longitudinal axis of the semi-finished product 102.

[0045] The semi-finished product 102, as shown in FIG. 17, has a section 103 having a smaller diameter, always shown on the left in FIG. 17, and a section 104, always shown on the right in FIG. 17, which has, when compared to the diameter of the section 103, a diameter that is roughly twice as large, wherein the difference in diameters between the sections 103 and 104 are irrelevant for the present invention. In addition, the semi-finished product 102 has at its side facing away from the thinner section 103 an end face 106. FIG. 17 shows the raw state 110 of the semi-finished product 102 before the embossing of a longitudinal groove or a rotary entrainment surface in the section 104 using any of the methods or apparatuses described herein.

[0046] The semi-finished connecting element 102 of FIG. 17 is embodied as a pipe-shaped semi-finished product 102. An internal pipe cavity 180 with a desired internal pipe diameter which extends concentrically with the longitudinal axis of element 102 can be found in the semi-finished product 102. Such semi-finished products are used, e.g., in hollow drill bits.

[0047] FIG. 2 shows a perspective view of a connecting element according to a first embodiment of the invention. FIG. 2 shows in the area of the section 104 a metal rod-shaped connecting element 100 made of the semi-finished connecting element 102 of FIG. 1 and provided with an end face 106. The first embodiment of the connecting-element 100 according to the invention shown in FIG. 2 represents a drill or chisel insertion end secured in an axially movable manner in a chuck of a hammer drill. The connecting element 100, which is located in the cylindrical section 104, and which is described in more detail with reference to FIGS. 4-7, has two longitudinal grooves closed on both sides 122 across from each other on the circumference of the section 104. The longitudinal grooves 122 have a planned length L. In the embodiment shown, the longitudinal grooves 122 serve as the locking grooves 124.

[0048] FIG. 3 shows a perspective view of a connecting element according to a second embodiment of the invention. The second embodiment of a connecting element 100 according to the invention shown in FIG. 3 is described in more detail below with reference to FIGS. 8-11. The essential difference between the second embodiment of the connecting element 100 and the connecting element 100 of FIGS. 2 and 4-7 is that two rotary entrainment surfaces 164separated by a right angle from the longitudinal grooves 122 along the circumferential direction of the circumference of the section 104two rotary entrainment surfaces 164 also located on the circumference of the section 104 across from each other, which are open towards the end face 106, embodied essentially as U-shaped grooves 162 in the depicted embodiment of FIGS. 3 and 8-11, are formed and/or embossed.

[0049] FIG. 4 shows the detail view A of FIG. 2.

[0050] FIG. 5 shows a top view of the connecting element 100 of FIG. 2.

[0051] FIG. 6 shows a sectional view of the connecting element 100 according to the sectional line C-C shown in FIG. 5.

[0052] FIG. 7 shows a sectional view of the connecting element 100 according to the sectional line B-B shown in FIG. 5.

[0053] FIG. 8 shows detail view A of the second embodiment of the connecting element 100 according to FIG. 3.

[0054] FIG. 9 shows a partial top view of the connecting element 100 of the second embodiment according to FIG. 3.

[0055] FIG. 10 shows a sectional view of the connecting element 100 according to the sectional line B-B shown in FIG. 9.

[0056] FIG. 11 shows a sectional view of the connecting element 100 according to the sectional line C-C shown in FIG. 9.

[0057] FIG. 12 shows a first embodiment of an apparatus 200 according to the invention for producing a connecting element 100 from a semi-finished connecting element 102, in particular for producing a drill or chisel insertion end secured in an axially movable manner in a chuck of a hammer drill. Apparatus 200 has a die 202 with an interior contour. The interior contour corresponds to at least one planned rotary entrainment surface 162 of the connecting element 100. The die 202 has one at least radially movable forming body 206 arranged in a recess 204 of the die 202. In the shown embodiment of FIG. 12, the forming body 206 is embodied as a rounded groove punch that can be radially applied and reset according to the double arrows 208 in the direction of the semi-finished connecting element 102. The rounded groove punch 206 serving as a forming body is used for forming at least one longitudinal groove 122 closed on both sides in the semi-finished product 102. A length LR measured along a parallel to the longitudinal axis of the semi-finished product 102 and/or, respectively, along a parallel to the double arrow 210 of FIG. 12 is smaller than the planned length L of the longitudinal groove 122 according to FIG. 2. In the exemplary embodiment shown in FIG. 12, the length LR of the rounded groove punch 206 corresponds to the diameter of the rounded groove punch 206 since the latter has a circular cross-section. Preferably, the diameter LR of the rounded groove punch 206 and/or, respectively, the length LR of the forming body 206 measured along a parallel to the arrow 210 is roughly between one and three times the width of the longitudinal groove 122 and less than 30% of the planned length L of the longitudinal groove 122 according to FIG. 2.

[0058] The forming of a longitudinal groove 122 according to FIG. 2 in the semi-finished product 102 is performed using the apparatus 200 of FIG. 12 by radially applying the forming body 206 and subsequently axially shifting the semi-finished connecting element 102 in a longitudinal die opening 214, which is matched to the outer circumference of the semi-finished product 102, of the die 202 according to the arrow 210. The longitudinal extension LR of the rounded groove punch 206 serving as a radially movable forming body is preferably one to three times that of a width B of the longitudinal groove 122 closed on both sides, which is shown in FIG. 5. In the exemplary embodiment shown in FIG. 12, the longitudinal extension LR of the rounded groove punch 206 corresponds to the width B of the planned longitudinal groove 122.

[0059] The apparatus 200 of FIG. 12 shows, for performing the shifting, an extrusion punch 212 acting in a longitudinal direction of the die 202 arranged by the double arrow 210 and an extrusion punch 216. The extrusion punch 212 is used for forming the rotary entrainment surface 164 during the insertion of the semi-finished connecting element 102 in the die 202; the extrusion punch 216 is used subsequently for forming the longitudinal groove 122 closed on both sides and for ejecting the semi-finished connecting element 102 from the die 202. By means of the extrusion punch 216 and the rounded groove punch 206, at least one longitudinal groove 122 closed on both sides can be formed in the semi-finished connecting element 102 by embossing. For this purpose, essentially, the radially movable rounded groove punch 206 is applied perpendicularly in the direction of the circumferential surface of the semi-finished connecting element 102 until the rounded groove punch 206 plunges into the circumferential surface of the semi-finished connecting element 102 to the desired depth of, in this case, 2.4 mm. Upon reaching the desired depth, this radial movement of the rounded groove punch 206 directed at the semi-finished connecting element 102 according to the arrow 208, is stopped. Then the extrusion punch 216 begins to expel the semi-finished connecting element 102 from the die 202 according to the end of the double arrow 210, shown in FIG. 12 on the right, in order to move the rounded groove punch, which has already plunged into the semi-finished connecting element 102, relative to the semi-finished product 102 and to thus form a longitudinal groove in the circumferential surface of the semi-finished product 102. The longitudinal groove then has a longitudinal extension corresponding to the sum of the circumference of the rounded groove punch 206 and the length of the shift of the punch 216 in the die 202.

[0060] FIG. 13 shows the apparatus of FIG. 12 from a different perspective and immediately before the start of the expulsion of the semi-finished product 102 from the longitudinal die opening 214 by the extrusion punch 216.

[0061] In a second embodiment of the apparatus according to the invention shown in FIG. 21, an additional, second die 202 having an extrusion punch 300 acting in this die's longitudinal die opening 214 can be provided for forming at least one rotary entrainment surface 162 in the semi-finished connecting element 102. This embodiment is characterized by the fact that extrusion punch 300 is arranged as an extension of each of the two longitudinal die openings 214 and 214. A first extrusion punch 300 is provided for forming the at least one rotary entrainment surface 162 in the semi-finished connecting element 102 during insertion in the second die 202, and a second extrusion punch 216 is provided for forming the at least one longitudinal groove 122 closed on both sides in the semi-finished connecting element 102 during the insertion in the die 202.

[0062] A third embodiment is shown in FIGS. 14-16. FIG. 14 shows a cross-section, FIG. 15 shows a longitudinal section, and FIG. 16 shows a perspective view of this embodiment. The embodiment of FIGS. 14-16 is characterized by the fact that outside of the die 202 and approximately perpendicular to the longitudinal die opening 214, at least one wedge 215 is arranged that, for embossing the at least one longitudinal groove 122 closed on both sides in the semi-finished connecting element 102 presses upon the at least one radially movable forming body 206 according to the double arrow 208. This embodiment is, according to FIGS. 14-16, further characterized by the fact that the at least one wedge 215 is attached as an interior cam surface 217 inside a bushing 218 rotatably supported concentrically to the die 202 in a bearing 222, and that by rotating the bushing 218 according to the double arrow 220, the force for forming the at least one longitudinal groove 122 closed on both sides is applied to the at least one radially movable forming body 206. FIGS. 14-16 show a state in which the forming bodies 206 have formed the longitudinal grooves 122 closed on both sides, and retraction of the forming bodies 206 from the grooves 122 is imminent by the rotating bushing 218 according to the double arrow 220 in a corresponding manner so that the cams 217 lose contact with the ends of the forming bodies 206 facing the cams 217.

[0063] Another, fourth embodiment, which is not shown, of the apparatus according to the invention and/or the method according to the invention is characterized by the fact that the die 202 has an interior contour corresponding to at least one planned rotary entrainment surface 162 of the connecting element 100 and that this at least one rotary entrainment surface 162 is formed by forced insertion of the semi-finished connecting element 102 in the die 202 in the direction of a longitudinal axis 210 of the die 202, and the at least one longitudinal groove 122 closed on both sides is embossed by radially applying the at least one forming body 206 movable in the die 202 and subsequent axial movement in the direction of the longitudinal axis 210 of the die 202. This embodiment can be further developed by performing the embossing of the at least one longitudinal groove 122 closed on both sides subsequent to the forming of the at least one rotary entrainment surface 162.

[0064] The method according to the invention can be characterized by the fact that the embossing of the at least one longitudinal groove closed on both sides is performed during the forming of the at least one rotary entrainment surface 162, preferably by the at least one radially movable forming body 206 being axially offset relative to a longitudinal die axis 210 from a front end of the at least one forming element 206, which is arranged in the die 202, for the at least one rotary entrainment surface 162.

[0065] The method according to the invention can further be characterized by the fact that the embossing of the at least one longitudinal groove closed on both sides begins upon completion of the forming of the at least one rotary entrainment surface 162 by the radial application of the at least one movable forming body 206 and is continued and/or completed by expelling the semi-finished connecting element 102 from the longitudinal die opening 214 under an axially acting force.

[0066] The method according to the invention can further be characterized by the fact that in a pipe-shaped semi-finished connecting element 102 having an interior pipe cavity 180 with an interior pipe diameter, interior pipe diameter is decreased or closed in the area of the at least one planned rotary entrainment surface 162 and the at least one planned longitudinal groove 122 by forming the at least one rotary entrainment surface 162 and/or the at least longitudinal groove using any of the methods described herein; further preferably or alternatively, the interior pipe diameter of element 102 is reduced or closed after an interior pin 400 profiled along its longitudinal axis by changes in its cross-section, is inserted in interior pipe cavity 180 in the semi-finished connecting element 102. In particular, the left end of interior pin 400 is initially inserted into the right end of interior pipe cavity 180 of element 102 and subsequently pushed into place in the interior of pipe cavity 180 so that the opposing ends of pin 400 are generally vertically aligned with the opposing ends of connecting element 102. Pin 400 has a shape similar to the shape of interior cavity 180 of element 102 but is smaller in size than the size of interior cavity 180 so that pin 400 can be disposed in interior cavity 180. Preferably, pin 400 has one or more recessed portions radially aligned or substantially radially aligned with the planned at least one groove and/or the planned at least one rotary entrainment surface wherein the recessed portion or portions provide sufficient space between the corresponding portion or portions of the section 404 of pin 400 and the corresponding portions of section 104 of element 102 to allow the at least one rotary entrainment surface and/or the at least one groove closed at both ends to be formed in section 104 of element 102. Referring to FIG. 18, for example, a portion of pin 400 (e.g., section 404) is shown as having an annular recess 406 that allows the at least one rotary entrainment surface and/or the at least one groove closed at both ends to be formed in section 104 of element 102 using any of the methods and/or apparatuses described herein.

[0067] The method according to the invention can be further characterized by the fact that the die 202 is divided at least once in its longitudinal direction 210, and the die halves or parts have at the time of, preferably just before, the expulsion a slight distance between them, relative to a diameter of the connecting element 100, 100. Referring to FIG. 20, a die 202 having two die parts or halves 202a and 202b are shown.