BG61233B1 - Plastic dowel for fixing rail to rc railway sleeper - Google Patents

Abstract

The dowel is used in railway transport. It can take up greater dynamic loads and has longer life. It is a hollow body (1) containing a longitudinal passage canal (2) which in its upper part (3) has the form of an inner truncated cone, being cylindical in its lower part (6). Trapezoidal female threading (8) is machined along the whole surface (7) of the canal (2). Each of the screw fillets (9) has an external trapeze (10) protruding to the longitudinal axis (5). An inner trapeze (12) made of glass-filled polyamide PAS-30 is made, concave to the wall (11) of the hollow body (1) between every two fillets (9). The external surface, in its lower part (6) is cylindrical and takes the shape of male threading (14) reaching the upper part (3) which externally takes the form of a truncated cone having the same wall (15) thicknesses along its entire length. The thickness of the wall (11) in its lower part (6) is the same along its entire length and is smaller than the wall thickness in its upper part (3).

Description

TECHNICAL FIELD

The invention relates to a plastic dowel for fastening the rail to a reinforced concrete crossbar, which is used in railway transport.

BACKGROUND OF THE INVENTION

A plastic dowel is known for attaching the rail to a reinforced concrete cross member, comprising a hollow body comprising a longitudinal through hole formed in its upper part as a stepped hexagon, and in its lower part a longitudinal passage through a cylindrical one. A profile inner thread is formed along the lower cylindrical surface of the longitudinal passage. The outer surface of the lower hollow body is cylindrical and is shaped like an external thread, beginning from the beginning of the lower part and extending to the beginning of the upper part, and has a length less than the length of the inner thread, such as the steps of the inner and the outer threads are equal. The thickness of the hollow body wall along the entire length of its lower body is the same and is greater than the thickness of the upper body wall in the area of the hexagonal / 1 /.

TECHNICAL NATURE

The plastic dowel for securing the rail to the reinforced concrete beam is a hollow body containing a longitudinal passage groove which is cylindrical at the bottom and its surface is shaped like an internal thread. The outer surface of the lower part of the hollow body is cylindrical and is shaped like an external thread, and the step of the inner thread is equal to the step of the outer thread, with the thickness of the wall of the lower part being the same along its entire length. According to the invention, the longitudinal passage channel at the upper part is formed as an inner truncated cone, whose formation concludes with the longitudinal axis at an angle α of 6 ° to 8 °. A trapezoidal internal thread is formed along the entire internal surface of the longitudinal passage duct and each of its turns contains a trapezoidal projection toward the longitudinal axis, and an inner trapezoid between each of the two turns is formed concave to the wall of the hollow body. The lengths of the large and small base of the outer trapezoid are smaller respectively than the lengths of the large and small base of the inner trapezoid, and the outer thread extends to the upper part, which is externally shaped as a truncated cone of uniform wall thickness along its entire length. . The thickness of each of the outer turns is less than the width of the concave part, which is part of a circle of radius R, and the transition of the concave part to its corresponding outer turns and back is arcuate with radius r, such that r / R = 0,42 - 0,44. The wall thickness of the lower part is less than the wall thickness of the upper part of the hollow body, the ratio of length 1 of the upper part to the length L of the lower part is 1 / L = 0.23 - 0.25.

The technical nature is further clarified by another embodiment in which the hollow body is made of polyamide.

The advantages of the invention are that the plastic dowel has a long service life and carries greater dynamic loads, since the wall of the conical upper part, which receives most of the impact, is thickened and its length and length are lower. 1 / L ratio = 0.24. In addition, the adhesion between the outer surface of the dowel and the reinforced concrete beam is improved because the transition of each of the basins to their respective outer turns and back is arcuate and its radius and radius of the basin are in the ratio r / R = 0,43.

DESCRIPTION OF THE FIGURES Attached

Figure 1 is a longitudinal half-view - half-section of the plastic dowel;

FIG. 2 is a longitudinal partial cross-sectional view;

EXAMPLES FOR IMPLEMENTATION

The plastic dowel for securing the rail to the reinforced concrete beam is a hollow body 1 comprising a longitudinal passage groove 2 formed in the upper part 3 as an inner truncated cone whose forming 4 concludes with a longitudinal axis 5 by an angle α = 7 ° and in the lower part 6 by a longitudinal passage pass channel 2 is cylindrical. A trapezoidal inner thread 8 is formed along the entire surface 7 of the channel 2, each of its windings 9 having an outer trapezoid 10 projecting toward the longitudinal axis 5, and between each two windings 9 it is concave to the wall 11 of the hollow body 1 of the inner trapezoid 12. The lengths of the large and small base of the outer trapezoid 10 are smaller, respectively, than the lengths of the large and small base of the inner trapezoid 12. The outer surface 13 in the lower part 6 of the hollow body 1 is cylindrical and is formed as an external thread 14 extending to the upper part 3 which is externally o shaped like a truncated cone of uniform wall thickness 15 along its entire length. The thickness of each of the outer turns 16 is smaller than the width of the concave portion 17, which is part of a circle of radius R. The transition 18 of the concave portion 17 to its corresponding outer turns 16 and back is arcuate with radius r, such that r / R = 0.43. The step of the inner thread 8 is equal to the step of the outer thread 14, and the thickness of the wall 11 of the lower part 6 is the same along its entire length and is less than the thickness of the wall in the upper part 3. The ratio of the length 1 of the upper part 3 and the length L of the lower part 6 is 1 / L ⁼ 0.24.

The invention is further elucidated by another example in which the hollow body 1 is made of polyamide - PAS-30.

The invention is not limited to the foregoing examples, the hollow body 1 may also be made of other suitable plastics.

APPLICATION OF THE INVENTION

Prior to pouring the concrete to obtain a reinforced concrete beam in its form (formwork), the dowels are placed and then the concrete is poured so that the front surfaces 19 of their upper part 3 coincide with the upper surface of the reinforced concrete beam.

Claims (2)

Claims 1. A plastic dowel for attaching a rail to a reinforced concrete beam, comprising a hollow body comprising a longitudinal passage groove which is cylindrical in the lower part and its surface is formed as an inner thread and the outer surface of the lower hollow body is cylindrical. shaped as an external thread, the step of the inner thread being equal to the step of the outer thread, and the thickness of the wall of the lower portion being equal along its entirety, characterized in that the longitudinal passage (2) in the upper part (3) is shaped k then an inner truncated cone whose generating element (4) concludes with an angle α from 6 ° to 8 ° with the longitudinal axis (5), a trapezoidal inner thread and each of the turns being formed along the entire inner surface (7) of the longitudinal passage groove (2). j (9) contains an outer trapezoid (10) convex to the longitudinal axis (5), and a recessed hollow body (1), an inner trapeze (12), formed between each of the two windings (9), with the lengths of the large and small bases of the outer trapeze (10) are smaller, respectively, than the lengths of the large and small bases of the inner trapezoid (12), and the outer p a tooth (14) extends to the upper part (3) which is externally shaped as a truncated cone of uniform wall thickness (15) along its entire length, with the thickness of each of the outer turns (16) being less than the width of the concave portion (17) representing a part of a circle of radius R and the passage (18) of the concave portion (17) to its corresponding outer turns (16) and back is arcuate with radius r, such that r / R = 0,42 - 0.44, and the thickness of the wall (11) of the lower part (6) is less than the thickness of the wall of the upper part (3) of the hollow body (1), by the ratio of length and 1 on the upper part (3) and the length L on the lower part (6) is 1 / L = 0.23 - 0.25. A plastic dowel for securing a rail to a reinforced concrete beam, according to claim 1, characterized in that the hollow body (1) is made of polyamide.