C-shaped frame and device for cold joining

Abstract

A C-shaped frame for a cold-joining tool has two leg sections spaced apart from one another and a connection section. A punch unit and a die unit are provided opposite one another to define a tool axis. The C-shaped frame has a first surface side and a second surface side. An outer contour of the C-shaped frame is determined by an outer edge of the C-shaped frame in the transition between the two surface sides. The C-shaped frame includes a reinforcing section provided on the outer edge along the outer contour of the C-shaped frame. There are multiple portions of the reinforcing section, each with an associated thickness dimension of the portion, over a profile of the reinforcing section as seen along the outer edge. The extent of the respective portions along the outer edge and parallel to a surface side is in each case at least 30 millimetres.

Claims

1. A C-shaped frame for a cold joining device, the C-shaped frame comprising: a first leg section and a second leg section, wherein the first and second leg sections are spaced apart from one another; and a connection section having at least one weakening section formed therein, wherein a free end of the first leg section is adapted to receive a punch unit of the cold joining device, and a free end of the second leg section is adapted to receive a die unit of the cold joining device, whereby the punch unit and the die unit are located opposite one another and define a tool axis, wherein ends of the leg sections that face away from the free ends are connected to one another via the connection section, wherein the C-shaped frame further comprises a first surface side and a second surface side opposite the first surface side, wherein an outer contour of the C-shaped frame is defined by an outer edge of the C-shaped frame in a transition between the first and second surface sides, wherein the C-shaped frame further comprises a reinforcing section provided on the outer edge of the C-shaped frame along the outer contour of the C-shaped frame, wherein multiple portions of the reinforcing section each have an associated thickness dimension over a longitudinal profile of the reinforcing section, as seen along the outer edge, wherein the thickness dimension of 2 to 6 of the multiple portions of the reinforcing section each differs from the thickness dimension of adjacent ones of the multiple portions of the reinforcing section in a direction of the longitudinal profile of the outer edge, wherein an extent of respective portions along the outer edge and parallel to a surface side in each case is at least 30 millimeters, and wherein an attachment part, comprising a flat flange for connecting the C-shaped frame to a robot arm, is located on a portion of the reinforcing section between the two leg sections, and extends into a central one of the at least one weakening section.

2. The C-shaped frame as claimed in claim 1, wherein the reinforcing section is formed within an edge strip, wherein the edge strip extends from the outer edge as far as a surface-side section, and wherein the surface-side section is spaced apart from the outer edge by at least 5 millimeters to a maximum of 150 millimeters.

3. The C-shaped frame as claimed in claim 1, wherein a thickness dimension of the reinforcing section of the C-shaped frame is greater than an average thickness dimension of the remaining part of the C-shaped frame.

4. The C-shaped frame as claimed in claim 1, wherein the reinforcing section is formed over at least 80% of a length of the outer edge of the C-shaped frame.

5. The C-shaped frame as claimed in claim 4, wherein the reinforcing section is formed over at least 90% of the length of the outer edge of the C-shaped frame.

6. The C-shaped frame as claimed in claim 1, wherein the reinforcing section has a thickness dimension that is at least twice as great as an average thickness dimension of a remaining part of the C-shaped frame.

7. The C-shaped frame as claimed in claim 1, wherein the reinforcing section has a thickness dimension that is more than 300% greater than an average thickness dimension of a remaining part of the C-shaped frame.

8. The C-shaped frame as claimed in claim 1, wherein the C-shaped frame has an overall frame height measured from the free end of a leg section at a point on the outer edge of the C-shaped frame in a direction of a longitudinal axis of the leg section and at right angles to the tool axis.

9. The C-shaped frame as claimed in claim 1, wherein the reinforcing section has an edge region that is offset from being parallel to the tool axis, and which defines 20% of a frame height.

10. The C-shaped frame as claimed in claim 1, wherein a thickness dimension of the reinforcing section is in a range of 30 millimeters to 150 millimeters.

11. The C-shaped frame as claimed in claim 1, wherein a cross-sectional area of the reinforcing section is in a range of 500 mm.sup.2 to 7000 mm.sup.2.

12. The C-shaped frame as claimed in claim 1, wherein the first leg section comprises two first beam sections, which are separated from one another by a first weakening section in the first leg section.

13. The C-shaped frame as claimed in claim 1, wherein the second leg section comprises two second beam sections, which are separated from one another by a second weakening section in the second leg section.

14. A cold joining device comprising the C-shaped frame as claimed in claim 1, wherein a punch unit of the cold joining device is provided at the free end of the first leg section, and wherein a die unit of the device is provided at the free end of the second leg section.

15. The cold joining device as claimed in claim 14, further comprising a drive unit assigned to at least one of the punch unit and the die unit, wherein the drive unit comprises a hydro-pneumatic drive with pressure boost and/or an electric drive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the present invention are explained by using arrangements according to the invention illustrated schematically in the figures.

(2) FIG. 1 shows a C-shaped frame according to the present invention in a view of a narrow side of the C-shaped frame facing away from the tool;

(3) FIG. 2 shows the C-shaped frame from FIG. 1 in a view of a surface side of the C-shaped frame;

(4) FIG. 3 shows the C-shaped frame in section according to the line A-A in FIG. 2;

(5) FIG. 4 shows the C-shaped frame according to FIGS. 1-3 in a perspective view; and

(6) FIG. 5 shows the C-shaped frame according to FIGS. 1-4, on which a punch unit and a die unit are accommodated.

DETAILED DESCRIPTION OF THE INVENTION

(7) A C-shaped frame 1 according to the present invention for a cold-joining tool according to FIGS. 1-4 is preferably formed in one piece and, for example, produced from a plate material blank, preferably from a steel material, for example, machined out. The C-shaped frame 1 comprises two leg sections 2 and 3 spaced apart from one another and a connection section 4.

(8) A free end 5 of the first leg section 2 is designed to detachably but firmly hold a punch unit 6 (see FIG. 5) of the associated cold-joining tool. A free end 7 of the second leg section 3 is designed to detachably but firmly hold a die unit 8 of the associated cold-joining tool. In the C-shaped frame 1 equipped for the tool use with the punch unit 6 and die unit 8 held thereon according to FIG. 5, the punch unit 6 and the die unit 8 are located opposite one another and predefine a tool axis W of the associated cold-joining tool.

(9) An approximately C-shaped or U-shaped outer contour 11 of the C-shaped frame 1 is determined by an outer edge 12 of the C-shaped frame 1. The outer contour 11 is formed in accordance with an outer peripheral narrow side of the C-shaped frame 1 in the transition between two surface sides 9 and 10 of the C-shaped frame 1. In the region reaching as far as the outer edge 12 or in the near region of the outer edge 12, a reinforcing section 13 of the C-shaped frame 1 having a respective thickness D1 or D2 is formed. The outer contour 11 and, therefore, the outer edge 12 have different points S1 to S7 following one another in the counterclockwise direction, based on the top view of the surface side 9 according to FIG. 2. The basis here is that the point S3 coincides with the free end 7 and the point S6 coincides with the free end 5.

(10) According to FIG. 2, viewed in the counterclockwise direction along the outer contour 11, the first leg section 2 is bordered by the outer edge 12 between the points S5 and S7. The second leg section 3 is bordered by the outer edge 12 between the points S2 and S4. The connection section 4, viewed in the counterclockwise direction along the outer contour 11, is accordingly bordered by the remaining part of the outer edge 12 between the points S7 and S2 and, relative to the leg sections 2 and 3, is bounded by the line A-A, which extends through the points S2 and S7. The two leg sections 2 and 3 are spaced apart by the part of the outer edge 12 between the points S4 and S5, wherein this part of the outer edge 12 bounds an edge section of the connection section 4.

(11) The ends of the leg sections 2 and 3 facing away from the free ends 5 and 7 on the line A-A between the points S7 and S5 in the leg section 2 and on the line A-A between the points S4 and S2 in the leg section 3, are connected to one another via the connection section 4. The connection section 4 reaches as far as the virtual line A-A illustrated in FIG. 2 and is bounded by the latter. The line A-A extends parallel to and offset from the tool axis W.

(12) The first surface side 9 of the C-shaped frame 1 is illustrated in top view in FIG. 2, wherein the second surface side 10 is opposite the first surface side 9. The C-shaped frame 1 comprises the reinforcing section 13, which is present on the outer edge 12 along the outer contour 11 of the C-shaped frame 1. Viewed over a profile of the reinforcing section 13 along the outer edge, the reinforcing section 13 has a plurality of portions, at least two here, each having an associated thickness transverse to the surface sides 9, 10. In the example of the C-shaped frame 1 illustrated, the reinforcing section 13 has two portions 14 and 15. Starting from the view according to FIG. 2 and in the counterclockwise direction along the outer contour 11, the portion 14 reaches from the points S1 via S2 and S3 as far as the point S4 with an associated constant or uniform thickness dimension D1 of the portion 14. The transition between the two portions 14 and 15 and from the thickness D1 to the thickness D2 is preferably formed with a concave taper, which in particular can be seen at the point S1 in FIG. 1.

(13) The second portion 15 accordingly reaches from the point S4 via S5, S6 and S7 as far as the point S1 with an associated constant or uniform thickness dimension D2. The thickness D1 is approximately 70% of the thickness D2.

(14) The reinforcing section 13, based on the two surface sides 9 and 10, is formed within an edge strip 16 or 17 and an inner boundary of the reinforcing section 13 coincides with the inner edge of the edge strips 16, 17. The edge strip 16 forms a loop-like outer peripheral part of the first surface side 9, and the edge strip 17 forms a part of the second surface side 10. The two edge strips 16 and 17 are opposite one another and, by way of example, are identical in their width B1 and B2. The reinforcing section 13 can alternatively have a different width on the surface side 9 than on the surface side 10.

(15) In the C-shaped frame 1, the width of the reinforcing section 13 or the width B1, B2 of the portions 14 and 15 is not constant; instead this width changes over the length of the relevant portion 14 and 15 along the outer edge with a respective unchanged thickness D1 and D2 here by way of example.

(16) Within the surface side 9 and 10, the edge strip 16 and 17 having the reinforcing section 13 extends from the outer edge 12 as far as a line 18, wherein the line 18 is spaced apart from the outer edge 12 by at least 5 millimeters to at most 150 millimeters, which predefines a value range for a maximum value of the width B1 and B2.

(17) The surface sides 9, 10, apart from the edge-side reinforcing section 13 and the free ends 5 and 7, are flat and level. Preferably, the planes respectively spanned by the surface sides 9 and 10 are aligned parallel to one another.

(18) The thickness D1 and D2 of the reinforcing section 13 is greater than an average thickness dimension Dm of the remaining part of the C-shaped frame 1 (see FIG. 3).

(19) The reinforcing section 13 is formed over virtually the whole length of the outer edge 12 of the C-shaped frame 1. Only in the region of the free ends 5 and 7 is the outer edge 12 of the C-shaped frame 1 adapted for the detachable attachment of the punch unit 6 and the die unit 8. Therefore, over a comparatively short section at the free ends 5 and 7, the outer edge 12 can have a normal thickness or a lower thickness than the thickness D1 or D2 of the reinforcing section 13.

(20) The C-shaped frame 1 has an overall frame height H, which from the distance between the tool axis W that can be provided on the C-shaped frame 1 and a point P of a center line of the outer edge 12 of the C-shaped frame 1, wherein the point P lies on a central plane centrally between those spanned by the two surface sides 9, 10, in which the tool axis W also lies.

(21) The reinforcing section 13 is formed on the C-shaped frame 1, preferably at least over the part on the outer edge 12 which, in the vertical direction of the C-shaped frame 1 from the tool axis W, is located on the other side of a vertical line parallel to the tool axis W, wherein the vertical line corresponds to a partial height H1, which makes up 20% of the total height H (see FIG. 2). This means that part of the leg sections 2, 3 is formed in the region of the free ends 5, 7 without any reinforcing section 13, which is due to the attachment of the punch unit and die unit 6, 8.

(22) The C-shaped frame 1 has a weakening section 19 in the first leg section 2 and a weakening section 20 in the second leg section 3 and a further weakening section 21 in the connection section 4. The weakening sections 19-21, each formed as a material-free region or as a material cutout or opening, permit a saving in material and therefore in weight of the C-shaped frame 1 with no detrimental effect that is relevant in practice with regard to the mechanical stability values of the C-shaped frame 1 according to the present invention in useful tool use. The reduced stability associated with the weakening sections 19-20 is at least compensated by the reinforcing section or an additional advantageous property of a predefinable elasticity behavior of the C-shaped frame and of the leg sections in the useful use of the tool formed thereby is achieved.

(23) The weakening sections 19 and 20 result in a structure of the two leg sections 2 and 3 each having two beam sections 22, 23 and 24, 25.

(24) Thus, the first leg section 2 has two first beam sections 22 and 23, and the second leg section 3 has two second beam sections 24 and 25.

(25) The weakening sections 19-21 do not reach as far as into the reinforcing section 13. The weakening sections 19-21 predominantly have a spacing relative to the reinforcing section 13. Only the weakening section 21 adjoins the reinforcing section 13 over short distances between the points S4 and S5.

(26) Provided on the reinforcing section 13, between the points S4 and S5, is an attachment point 26 such as, for example, a flat flange section 27, for example, for the connection to a robot arm.

(27) FIG. 5 shows, on the C-shaped frame 1 for use in a cold-joining tool, the punch unit 6 having a punch element 28, which can be driven reversibly and linearly in the direction R1 and R2 by a drive unit 30. The die unit 8 having a die element 29 is provided opposite. A workpiece that can be processed by the cold-joining tool, such as two or more sheet metal layers, which can be clamped between a free end of the punch element 28 and the die element 29 in order to be processed, is not illustrated in FIG. 5.

(28) In FIG. 5, the elastic deformation behavior of the C-shaped frame 1 equipped with the punch unit and die unit 6, 8 is indicated in practical tool operation, for example, during a riveting or clinching process.

(29) With loading of the C-shaped frame 1 with the tool working, the two leg sections 2 and 3 or their respective beam sections 22, 23 and 24, 25 deform in such a way that a bending-open effect of the C-shaped frame 1 and the leg sections 2, 3 does not detrimentally occur in practice.

(30) The deformation of the beam sections 22-25 is indicated highly schematically and unrealistically to an exaggerated extent with dashed lines in FIG. 5. The deformation V22 for the deformation of the beam section 22, the deformation V23 for the deformation of the beam section 23, the deformation V24 for the deformation of the beam section 24 and the deformation V25 for the deformation of the beam section 25.

(31) As a result of the deformations V22 to V25, which are substantially determined by the formation and mutual matching of the weakening sections 19, 20 and 21 and the reinforcing section 13, the beam sections 22-25 bend such that a tool offset and skewing or an axial offset is advantageously lower than in known C-shaped frames during tool use. An absolute deformation of the leg sections 2, 3 in the direction of the force or along the tool axis W can be comparatively greater in the C-shaped frame 1 according to the present invention during tool use than in known arrangements, but this is not critical or can be compensated by a somewhat longer driven movement path of the punch element 28.

(32) Because of the indicated deformations V22-V25 of the beam sections 22-25, during tool use the punch unit 6 and therefore the punch element 28, as a rule superimposed on the driven movement of the punch element 28 in the direction R1 or R2, move virtually linearly and parallel to the tool axis W in the direction R6 and back again counter to R6, without any practically relevant skewing of the longitudinal axis of the punch element 28 relative to the tool axis W.

(33) In a corresponding way, during tool use the die unit 8 and, therefore, the die element 29, in the direction R8 and back again counter to R8, move virtually linearly and parallel to the tool axis W without any practically relevant skewing of the longitudinal axis of the die element 29 relative to the tool axis W.

(34) The deformations V2 of the inner beam section 22 and the deformation V24 of the inner beam section 24 are, for example, curved concavely inward toward the weakening section 19 and toward the weakening section 20 in relation to the unloaded state according to FIG. 2. A corresponding deformation or bulging in the same direction is exhibited by the outer beam section 23 of the first leg section 2 and the outer beam section 25 of the second leg section 3, that is to say bulging outward.

(35) In known C-shaped frames, in particular of uniformly plate-like design without weakening sections in particular deliberately formed to this effect, the leg sections deform precisely differently with an inwardly curved or an inwardly convex bulging of inner narrow sides of leg sections of the known frame.

LIST OF DESIGNATIONS

(36) 1 C-shaped frame 2 Leg section 3 Leg section 4 Connection section 5 End 6 Punch unit 7 End 8 Die unit 9 Surface side 10 Surface side 11 Outer contour 12 Outer edge 13 Reinforcing section 14 Portion 15 Portion 16 Edge strip 17 Edge strip 18 Line 19 Weakening section 20 Weakening section 21 Weakening section 22 Beam section 23 Beam section 24 Beam section 25 Beam section 26 Attachment point 27 Flange section 28 Punch element 29 Die element 30 Drive unit