Abstract
A connection element for an interlocking connection to at least one component includes at least one component held between the connection element and a securing element wherein the connection element and the securing element enter into a friction welded connection, having a head with a drive and a shaft having at least two cutting structures on a front side. The at least two cutting structures have cutting edges situated in a cutting plane, wherein the cutting plane borders the shaft, and the at least two cutting structures are also spaced apart in the circumferential direction and define a cutting diameter. A cross-section of the shaft has a reduced extension between the cutting structures relative to the cutting diameter, wherein the area of the reduced extension extends in the axial direction at least with the length of the cutting diameter from the cutting structures in the direction of the head.
Claims
1. Connection element for positive connection to at least one component, said at least one component is held between the connection element and a securing element, and said connection element and said securing element enter into a friction-welded connection, comprising: a head with a drive and a shaft, said shaft includes a solid section extending from the head to a front side thereof, said front side includes at least two cutting structures, said cutting structures have cutting edges that lie in a cutting plane, wherein the cutting plane bounds the shaft, said cutting structures are also spaced apart in the circumferential direction and define a cutting diameter, wherein the shaft also has a cross-section having chamfers defining an area of reduced extension between the cutting structures relative to the cutting diameter, wherein the chamfers defining the area of reduced extension extend in the axial direction from the cutting structures towards the head at least the length of the cutting diameter, said chamfers discharge shavings axially towards the head.
2. Connection element according to claim 1, wherein the maximum radial extension of the cutting structures in the cutting plane is 25% at the most, of the cutting diameter.
3. Connection element according to claim 1, wherein the shaft has a cross-sectional area of at least 60% of the area defined by the cutting diameter.
4. Connection element according to claim 1, wherein a maximum of five cutting structures are provided.
5. Connection element according to claim 1, wherein the center of the front side of the shaft is spaced from the cutting plane in the direction of the head by a maximum of 50% of the cutting diameter.
6. Connection element according to claim 1, wherein the area of reduced extension is produced by providing recesses in the shaft.
7. Connection element according to claim 1, wherein the shaft is cylindrical.
8. Connection element according to claim 1, wherein the cutting diameter is ≤2.5 mm.
9. Connection element according to claim 1, wherein the reduced extension decreases constantly in the direction of the head.
10. Connection element according to claim 1, wherein the maximum radial extension of the cutting structures in the cutting plane is 20% at the most, of the cutting diameter.
11. Connection element according to claim 1, wherein the area of reduced extension is produced by providing grooves in the shaft.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Throughout the description, the claims and the drawings, those terms and associated reference signs are used as are listed in the List of Reference Signs below. In the drawings:
(2) FIG. 1A is a perspective view of a connection element according to the invention;
(3) FIG. 1B is a perspective view of a securing element according to the invention;
(4) FIG. 10 is a perspective view of a connection element according to the invention;
(5) FIG. 1D is a perspective view of a securing element according to the invention;
(6) FIG. 2A is a front view of a connection element according to the invention;
(7) FIG. 2B is a longitudinal sectional view of a connection element of FIG. 2A;
(8) FIG. 2C is a cross-sectional view of a shaft of a connection element of FIG. 2A;
(9) FIG. 3A is a top view of a securing element of FIG. 1B;
(10) FIG. 3B is a sectional view of a securing element of FIG. 3A;
(11) FIG. 4A is a front view of an inventive connection element of FIG. 10;
(12) FIG. 4B is a longitudinal sectional view of a connection element of FIG. 4A;
(13) FIG. 4C is a cross-sectional view of a shaft of a connection element of FIG. 4A;
(14) FIG. 5A is a top view of an inventive securing element of FIG. 10;
(15) FIG. 5B is a sectional view of an inventive securing element of FIG. 5A;
(16) FIG. 6 is a perspective view of a connection element according to the invention;
(17) FIG. 7 is a sectional view of another inventive embodiment of a securing element;
(18) FIG. 8 is a partial sectional view of a component connection according to the invention;
(19) FIG. 9 is a sectional view of a component connection according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
(20) FIG. 1A is a perspective view of a connection element 10 according to the invention. FIG. 1B is a view of a securing element 30 which corresponds to the connection element 10 of FIG. 1A, to which the connection element is materially connected in a friction-welding process after it has penetrated a securing structure having at least one component. The connection element 10 illustrated in FIG. 1A and the securing element 30 illustrated in FIG. 1B together form a connection system.
(21) FIG. 10 is a perspective view of another embodiment of a connection element 40 according to the invention. FIG. 10 is a perspective view of a securing element 50 according to the invention. The connection element 40 and the securing element 50 are matched to each other so as to yield an as large as possible frictional surface at the point where the elements make contact.
(22) FIG. 2A is a front view of a connection element 10 according to the invention for producing a friction-welded connection to a securing element, in particular of the type illustrated in FIG. 1B, to enable a securing structure to be held between a head 12 of the connection element 10 and the securing element. The connection element 10 has a cylindrical shaft 14 the front side of which terminates in a cutting plane E.sub.S in which two cutting edges 18 are situated. The cutting edges define a cutting diameter D.sub.S which can be used to form a hole in the securing structure in a shaving-removing manner.
(23) The shaft 14 has a chamfer 16 which extends from the cutting plane E.sub.S towards the head 12. Furthermore, another chamfer (see FIG. 2B) is provided opposite this chamfer 16, which results in an area of reduced cross-section with respect to the cutting diameter D.sub.S in the region of the chamfers 16. This is shown in more detail in FIG. 2C. The shavings removed from the securing structure by the cutting edges 18 will thus be discharged axially from the cutting plane E.sub.S towards the head 12 within the chamfers 16 as a result of the rotation of the connection element 10 and will thus be conveyed out of the securing structure against the drilling direction.
(24) When the chamfers 16, 20 are formed, this also creates the cutting structures 18 located on the front side of the shaft 14 in a single step.
(25) A recess is provided between the cutting edges. This recess acts to space the center of the shaft end from the cutting edge E.sub.S by approx. half of the cutting diameter D.sub.S. This ensures that the cutting edges 18 will reliably penetrate the securing structure.
(26) FIG. 2B is a longitudinal sectional view IIB-IIB with opposing chamfers 16, 20 located in the area of the shaft end. The depth of the chamfers 16, 20 decreases constantly with a small pitch in the direction of the head 12. This view also shows the distance A of the point of intersection of the shaft front face with the central axis from the cutting plane E.sub.S. This distance is 50% of the cutting diameter D.sub.S.
(27) FIG. 2C is a cross-sectional view IIC-IIC through the shaft 14, said cylindrical shaft 14 having the cutting diameter D.sub.S. Furthermore, this view clearly shows the design of the areas of reduced extension created by the chamfers 16, 20. These recesses which extend in an axial direction act to discharge the shavings produced at the cutting edge in an axial direction against the drilling direction.
(28) FIG. 3A is the top view of a securing element 30 according to the invention as shown in FIG. 1B whose design matches that of the connection element 10.
(29) FIG. 3B is a sectional view along lines IIIB-IIIB of FIG. 3A of a rotationally symmetrical securing element 30 according to the invention which is provided for securing a connection element 10 of the type illustrated in the views of FIG. 2A to 2C. The securing element 30 has a hexagonal outer contour, with the edge area 32 defining an abutment plane E.sub.A.
(30) On the interior of the edge area, a deposit area 34 is provided which is spaced from the abutment plane E.sub.A. As seen in the embodiment illustrated in FIG. 1C, the deposit area 34 is of an annular design. Provided within this annular deposit area 34 is a welding area 36 which is raised towards the abutment plane E.sub.A with respect to the level of the deposit area 34. The welding area 36 is of a convex spherical-cap shape, with the curvatures of the front face of the connection element 10 (FIG. 1A) and the welding area 36 being matched to each other. This first of all provides an as large as possible abutment surface between the components to be joined in a friction-welding process. Secondly, the raised spherical-cap shaped portion promotes the sliding down of shavings falling into the securing element during rotation of the connection element 10. This ensures that no shavings will remain in the zone of the joint which would adversely affect the friction-welded connection of the connection element to the securing element 30.
(31) FIG. 4A is a front view of another inventive embodiment of a connection element 40 comprising a head 42 and a shaft 44. Also the embodiment of FIG. 4A has cutting edges 46 on the front side end of the shaft, which cutting edges 46 are adapted to cut holes in a shaving-removing manner. In contrast to FIG. 1A, the recesses 47A are made into the cylindrical shaft 44 in the shape of a wedge, in particular by pinching, Same as in FIG. 1A, in this embodiment, the recess also extends in the axial direction from the cutting plane toward the head with a length that is longer than the cutting diameter DS.
(32) FIG. 4B is a sectional view taken along lines IVB-IVB of FIG. 4A: This sectional view shows the course of the recesses 47A, 47B. The extension of the cross-section in the area of reduced extension increasingly diminishes in the direction of the head. The depth of the recess decreases towards the head 42 up to a point where the complete shaft cross-section is reached again.
(33) FIG. 4C is a cross-sectional view of the shaft 44 taken along the cutting lines IVC-IVC of FIG. 4A, which produces areas of smaller extension 48 with respect to the cutting diameter D.sub.S. The wedge-shaped recess illustrated in FIGS. 2A and 2B has the advantage that it can be produced particularly easily and yet ensures a reliable discharge of the shavings from the cutting area.
(34) FIG. 5A is a top view of a securing element 50 according to the invention as seen in FIG. 1D which is of a design that matches the connection element 40.
(35) FIG. 5B is a sectional view taken along lines VB-VB of FIG. 5A. In contrast to the securing element illustrated in FIG. 1C, the welding area 52 is of a conical design here. Also this design allows the shavings produced during the penetration process to slide into the deposit area 54. Moreover, this design provides an as large as possible frictional surface for a connection element 40 having the design illustrated in FIG. 2A. The welding diameter D.sub.2 of the securing element 50 corresponds roughly to the cutting diameter D.sub.S of the connection element 40. This provides an ideal joining zone and ensures fast fusing of the components 40, 50 to be joined.
(36) FIG. 6 is a perspective view of a connection element 60 according to the invention, in which the area of reduced extension is produced by providing a groove 61 in the cylindrical shaft 62 of the connection element 60. The base of the groove 61 extends parallel to the axis of the connection element 60 and, at its end facing the head, increases to the level of the circumferential surface of the shaft 62.
(37) FIG. 7 is a sectional view of another embodiment according to the invention of a securing element 70 which has an annular deposit area 72 within which a hemispherical welding area 74 is provided. The radial extension of the abutment area 76 is designed such that the latter will at least partially extend beyond the deposit area 72 in the radial direction, thus forming an undercut. This has the advantage that the fusing of the components to be joined results in a widening of the weld bead, resulting in an additional interlocking connection, besides the material connection, in the embodiment corresponding to the view of FIG. 9.
(38) FIG. 8 is a partial sectional view of a component connection 80 according to the invention, comprising a first composite sheet 82 and a second composite sheet 84. Both composite sheets 82, 84 are made of FRP. Both composite sheets are held together according to the invention by providing an interlocking connection between the head 86 of a connection element 88 and a securing element 90. The connection between the connection element 88 and the securing element 90 is produced by providing a friction-welded connection between the connection element 88 and the securing element 90 at the joining zone 92 where the shaft of the connection element 88, once it has penetrated the composite sheets 82, 84 in a shaving-removing manner as described above, is then secured in place. During the shaving-removing hole forming process, shavings produced as a result of the aforementioned design of the connection element 88 will be discharged from the connection of composite sheets for as long as the portion of the shaft provided with a groove projects from the topmost composite sheet 82. However, as it is not possible to discharge all shavings against the drilling direction, the remaining shavings will be received in the deposit area 94 of the securing element 90. The shavings held there will thus not adversely affect the friction-welded connection. Despite a preferably small diameter of the shaft, this will ensure a high connection strength. As can be seen from the partial sectional view of FIG. 8, both the connection element 88 and the securing element 90 have an external drive in the shape of a hexagon. This is a common form of drive.
(39) FIG. 9 is a sectional view of a component connection 100 according to the invention, similar to the view of FIG. 8, in which the securing element 102 according to the embodiment of FIG. 7 is shown. It can clearly be seen in this sectional view that the abutment area 104 extends somewhat beyond the deposit area 106 of the securing element 102 in the radial direction. The friction weld bead 110 formed thus provides an interlocking connection in addition to the material connection at the joining zone 108.
