Plastic dowel for fastening of a rail and combination of such a plastic dowel and a rail screw
The present invention relates to a plastic dowel for the fastening of a rail on a solid substrate. The plastic dowel includes an opening, an interior, a shank section, and a holding section, which provides at least one circumferential projection around its circumference. The at least one projection protrudes in a radial direction whereby the upper flank of the projection of the holding section assigned to the dowel opening is aligned at an angle of 90°±3° in relation to a longitudinal axis of the plastic dowel.
1. A plastic dowel for fastening a rail on a solid substrate, with a dowel opening formed at an end face of the plastic dowel for insertion of a rail screw into the plastic dowel, with a dowel interior space enclosed by the plastic dowel, with a shank section which connects to the dowel opening of the plastic dowel, and with a holding section which connects to the shank section of the plastic dowel and which is provided on an outer side with at least one projection running around its circumference and protruding in a radial direction which, in a finished installed state, engages with a material of the solid substrate enclosing the plastic dowel, wherein the projection of the holding section is formed as an external thread and an upper flank of the projection of the holding section is orientated at an angle of 90°±3° in relation to a longitudinal axis of the plastic dowel,
wherein the dowel has an internal thread on an inner side, and a flank of the internal thread is orientated at an angle of 90°±3° in relation to the longitudinal axis of the plastic dowel.
2. The plastic dowel according to claim 1 , wherein an inner circumferential face or outer circumferential face of the shank section is smooth.
3. The plastic dowel according to claim 1 , wherein a second holding section connects to a first holding section of the plastic dowel, in said second holding section also at least one radially outwardly protruding projection is formed or a respective internal thread is continued, and in that a flank of the projection or of the internal thread in the second holding section is arranged at an angle of more than 93° in relation to the longitudinal axis of the plastic dowel or is rounded.
4. The plastic dowel according to claim 1 , wherein the upper flank in a first holding section is orientated in each case at an angle of 90°±1° in relation to the longitudinal axis of the plastic dowel.
5. The plastic dowel according to claim 1 , wherein a transition from an underside of a flank of the projection or of an upper flank of the internal thread to a respectively assigned circumferential face of the plastic dowel has a rounded form.
6. The plastic dowel according to claim 1 , wherein a lower flank of the projection or of the internal thread has a convex domed form.
7. The plastic dowel according to claim 1 , wherein a transition from an underside of the upper flank of the projection or of an upper flank of the internal thread of a second holding section to the flank of an associated projection or of a second holding section to the internal thread has a rounded form.
8. The plastic dowel according to claim 1 , wherein on an outer side of the plastic dowel in the area of a first holding section at least one web connected to the shank section and extending in a longitudinal direction of the plastic dowel is formed,
the width of said web in a base area being equal to at least a fifteenth of a circumference of the plastic dowel,
said web crossing the projection of the first holding section and
an apex face of said web extending at most to an imagined prolongation of the envelope of the shank section.
9. The plastic dowel according to claim 8 , wherein two or more webs are provided which are arranged at same angular intervals about the longitudinal axis of the plastic dowel.
10. The plastic dowel according to claim 1 , wherein in an area of a first holding section a groove-shaped recess extending in a longitudinal direction of the plastic dowel is formed in an inner circumferential face.
11. The plastic dowel according to claim 10 , wherein the recess is formed in an area of a web, the web provided in each case on the outer side of the plastic dowel.
12. The plastic dowel according to claim 1 , wherein a recess intersects the internal thread.
13. A combination of a rail screw and a plastic dowel formed according to claim 1 , wherein the rail screw has a screw head and a threaded screw shank following the screw head in a longitudinal direction of the rail screw, a circulating screw thread being formed on said screw shank, wherein an upper flank of the screw thread is orientated at an angle of 90°±3° in relation to a longitudinal axis of the rail screw.
14. The combination according to claim 13 , wherein the upper flank is orientated at an angle of 90°±1° in relation to the longitudinal axis of the rail screw.
15. The combination according to claim 13 , wherein a core of the rail screw tapers conically towards a screw tip, at least in an area in which the screw thread is present.
16. The combination according to claim 13 , wherein the screw thread extends over an entire length of the screw shank in a radial direction as far as a cylindrically formed envelope of the screw shank.
17. The combination according to claim 13 , wherein, between the screw head and the thread section, the rail screw has a shank section whose circumferential face is smooth.
18. The combination according to claim 13 , wherein an envelope of a circumferential face of the shank section coincides with a cylindrical envelope of the thread section.