JPS60156839A - Screw anchor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a coarsely threaded portion tapering toward a distal end;
a conical head portion having a central blind hole starting from its front end;
A screw for screwing in the fixing element and a polygonal complementing vertical groove for inserting a tool to unscrew and remove the screw, which can be cast integrally in concrete and can be unscrewed and removed from the concrete. Regarding anchors.

This type of screw anchor is described in British patent specification 81584.
414. Screw anchors of this type are applied above all to so-called climbing frames (e.g. weirs and power plants) and therefore only occasionally have to be roughly fixed to the concrete and where the fixing location is known before the concrete is poured. applies everywhere. Its use is very economical due to the ability to replace the expensive screw anchors.

For example, the attachment to the temporary frame is carried out by means of typical fastening elements, such as machine screws. In order to overcome the relatively large span widths, correspondingly relatively long drawbars will be used. The latter is the case, for example, when the fastening element has to penetrate multiple strip thicknesses or the like. However, in this case, as a rule, relatively thin screws must be screwed out with great effort. Cleaning threads is time consuming. Experience has therefore shown that workers prefer to use unused stockpiles.

The problem of the present invention is to maintain a threaded tightening method that accommodates optimal transverse forces, while also providing a threaded connection primarily intended for the transmission of tensile forces for threaded rods with favorable conditions regarding cleaning. The object of the present invention is to form a screw anchor of the type mentioned at the outset in a manner that is technically simple to manufacture and advantageous in terms of use.

This problem is solved by the invention set forth in claim 1.

The embodiment section shows advantageous developments.

This creates a screw anchor of the type mentioned at the beginning with increased utility and safety. Two different screws can be freely selected. One screw is useful for accepting commercially customary machine screws, for example when relatively large lateral forces have to be transmitted through the anchored screw anchor, yet press-less steel. Tuned other screws are mainly applied when tensile forces have to be transmitted via the screw anchor. Corresponding prestressed steels are widely used in architectural construction and are therefore practically always at hand. These very rough prestressed steel screws with relatively wide rib spacing have
It has the advantage of being extremely resistant to contamination and damage to concrete. Moreover, interrupting the screw rip results in a high degree of self-cleaning effect. The concrete that has penetrated approximately into the ring space at the height of the fine threads is at least partially pulled together and crushed during loosening and removal of the prestressing steel.

In addition, prestressed steel has the advantage that its threads have a lead angle in the range of lOo or 15°, which allows for rapid adjustment of the action. Any kind of stability drop is caused by the fact that the screws that are coaxial and one behind the other extend inward to the fx head section and thus extend to an area that does not have any mantle side markings (threads). will not occur. In addition, 6 parts of the subsequent roughening remain intact. It is advantageous to divide the entire thread length in such a way that the blind hole carrying the internal thread has approximately the same length as the prestressed steel threaded hole. By stepping the thread transition, the small cross-section of the prestressed steel provides maximum protection as it contrasts sharply with the fine threads of the blind hole.

The subject matter of the invention will be explained in more detail below with reference to embodiments shown in the drawings.

The screw anchor 1 has a base body that tapers conically towards the tip 2. On the distal side, there is a coarse thread 3 of a single thread running over approximately 273 of the entire length of the screw anchor, with varying thread heights. The lead angle is 15°. The pitch will be 29mm. The tip 2 and the front end 4 of the other screw anchor end face transversely to the central longitudinal axis X--X of the screw anchor 1, the front edge being chamfered.

The head part 5, which is divided into approximately 1/3 of the total length of the screw anchor 1, has a central blind hole 6 starting from the front end 4. The circular inner surface is, for example, a mechanical screw 7 (the ninth
It carries a screw G1 for screwing in a fastening element in the form of (see figure).

Further, the blind hole 6 is formed with four vertical grooves 8 wrapped around a polygon. These longitudinal grooves project the screw base circle by an amount equal to the thread height and extend over the entire length of the screw G1. On the front side, the entrance to the blind hole has a conical chamfer 9.

With a square groove, it is possible to introduce a bushing wrench with a correspondingly square cross section. but,
The drawing shows a bushing wrench 0. The blind hole 6 carrying the screw G1 follows the screw-thread (LIO) coaxially and therefore also in the longitudinal central axis X--X, which screw is designated G2. It is.

The screw G2 is likewise still inside the head part 5 and has a smaller diameter than the blind hole 6 carrying the screw G. In this way, a ring-shaped step 11 is created between the two threaded regions. The ring step is funnel-shaped in the direction of the screw-threaded hole 10, so that a screw bolt in the form of prestressed steel 12 with a corresponding mating thread is centered.

The prestressed steel 12 has threaded ribs 13 rolled on both sides on its outer periphery. It is a coarse screw tap with trapezoidal cross section. The diametrically opposed threaded ribs 13 each extend approximately over a quarter of the prestressing steel - the mantle surface M. Their adjacent end faces 13' are about 150
It runs into the mantle surface of the cylindrical prestressed steel core at an obtuse angle of . The concrete placed in the hollow ring space 14 is later removed when the prestressing steel 12 is loosened. At that time, the threaded rib 13
actually acts like a milling cutter. At that time, the finer screw G1 and the threaded rib 13 do not even come into contact. Threaded ribs 13 make it possible to carry out the evacuation action without damage. The width of the helical grooves between the threaded ribs, which are the fragments simultaneously produced when the concrete-ring filling is crushed, is clearly larger than the width of the threaded ribs. At that time, relatively large fragments are sent beyond the lick surrounding space of the threaded rib,
It can then be captured by the end face 1g' of the next threaded rib.

On the distal side, the prestressed steel-screw-threaded bore 10 continues into a threaded end 16 as well as an unthreaded portion 16', which finally terminates in a conically shaped hollow tip 16''. A coarse screw 3 is screwed into the mantle surface of the screw anchor at the height of this hollow tip 16''.

The head part 5 has a division such that the blind hole 6 and the prestressed steel screw screw hole 1° are approximately of the same length, taking into account the holes of both screw specifications.

An example of application becomes clear from FIGS. 8 and 9.

FIG. 8 shows a one-sided vertical frame wall 17 with a vertical strip 18 held by a support frame 9. FIG. 1. remaining on the bottom 22 lying on the angle bisector between the horizontal concrete foundation part 20 and the vertical concrete foundation part 21 and inclined and therefore perpendicular to the angle bisector 1. A set screw anchor 1 receives a screwed prestressing steel 12. This prestressing steel 12 passes through the crossbeam 18' and is screwed therein by a tightening device 23 with a screw.

In FIG. 9, a corresponding prestressing steel 12 is present in the climbing frame 24. In the lower part of the temporary frame, the screw anchor 1 has already been loosened and removed again. The screw anchors recovered in this way can then be assigned to the temporary frame wall 17 placed therein. This screw anchor is fixed using a machine screw 7. The machine screws 7 pass through well-fitting holes in the temporary frame wall 17. The machine screw 7 reliably draws the flat front end 4 of the screw anchor 1 to the inner surface of the temporary frame wall 17 close to the hole. By additionally filling the spaces between the temporary walls, the monolithically cast concrete surrounds the freely projecting screw anchors 1, which can be released again if necessary after the concrete has hardened.

All new features described in the description and shown in the drawings are essential to the invention, even if not explicitly stated in the claims.

[Brief explanation of the drawing]

1 is a side view of the screw anchor, FIG. 2 is the head of the screw anchor of FIG. 1, mainly in section and shown approximately to actual scale, and FIG. 3 is a front view of the screw anchor;
Figure 4 is a side view of the prestressed steel section, and Figure 5 is a side view of the prestressed steel section.
The plan view of the prestressed steel shown in the figure, Figure 6 is line VI of Figure 4.
-■ cross-sectional view, Figure 7 is a diagram corresponding to Figure 2 when prestressed steel is screwed in, Figure 8 is a conc IJ
- Diagram showing an example of the use of a temporary frame on one side and a screw anchor and prestress steel when fixing to the bottom of a base, No. 9
The figure shows an example of the use of a so-called climbing temporary frame. 1...Screw anchor 8...Coarse thread part 5...
・Head part 6... Blind hole 8... Vertical groove 10... Prestress steel - Screw - Screw hole 11...
・Ring stepped part 12...Prestress steel G1...Screw G2...Screw Agent: Hikaru Esaki Good agent: Hikaru Esaki

Claims (2)

[Claims] (1) having a roughened portion tapering towards the tip and a rounded head portion, the head portion having a central blind hole starting from its front end, and having a cylindrical inner surface of the blind hole; is formed with a screw for screwing in the fixing element and a complementary vertical groove in a polygonal shape for inserting a tool for loosening and removing the screw, which can be cast integrally in the concrete and can be unscrewed from the concrete. characterized in that, in the removable anchor, the blind hole (6) is stepped and continues into a prestressed steel-screw-threaded hole (10) running inside the head part (5). Anchor to. (2) The blind hole (6) and the prestressed steel screw threaded hole (10) have the same length.
Anchors listed in section.