RU190217U1 - ANTIQUE TUBULAR FRICTION - Google Patents

Abstract

The utility model relates to the mining industry, in particular, to the anchor supports, and can be used to fasten the mine workings of mines and mines. that the tubular friction anchor is made in the form of a hollow metal tube with a longitudinal slit along the entire length, with a support ring welded at one end to hold the supporting element This, characterized in that the anchor is made of sheet metal with pre-applied periodically repeating stiffening corrugations located transversely relative to the longitudinal axis of the anchor. The technical result is also achieved by the fact that the corrugations of stiffness are made with a height of 0.5 to 2.0 mm. The technical result is also achieved by the fact that the corrugations of stiffness are made with a width of 2.0 to 10.0 mm. The technical result ostigaetsya also in that the distance between the tops of the corrugations is the stiffness of 2.0 to 60.0 mm. 5 il.

Description

The technical field to which the utility model

The invention relates to the mining industry, in particular to the anchor supports, and can be used for fastening the mine workings of mines and mines.

The level of technology

Technical solutions are known (RU 155346 U1, priority date 01/14/2015; RU 161881 U1, priority date 30.09.2015; RU 171624 U1, priority date 09/26/2016, IPC E21D 21/00).

Known tubular anchoring type "Split-Set", the closest in technical essence to the proposed utility model. Anchor lining includes a steel pipe with a longitudinal slit along the entire length and a constant width supporting the flange to hold the support plate, and the head end of the lining is made in the form of a truncated cone for ease of installation in a well of smaller diameter than a steel pipe (Scott D. New anchor lining. - Glukauf, 1980, N 3, p. 6-10) (prototype).

The disadvantage of the technical solution adopted for the prototype is the low stability of the anchor buckling that occurs during its installation in the hole of smaller diameter.

Disclosure of utility model

The technical result, which is aimed at ensuring the proposed utility model, is to increase the stiffness (stability of buckling) of the anchor.

The technical result is achieved by the fact that the tubular friction anchor is made in the form of a hollow metal tube with a longitudinal slit along the entire length, a support ring for holding the support element welded at one end, characterized in that the anchor is made of sheet metal with pre-applied periodically repeated stiffenes transverse to the longitudinal axis of the anchor.

Description of the drawings

FIG. Figure 1 shows a side view of a tubular friction anchor complete with a support element made of sheet metal with stiffenings prior to installation into the hole.

FIG. Figure 2 shows a front view of a tubular friction anchor complete with a support element made of sheet metal with stiffen corrugations arranged transversely relative to the longitudinal axis of the anchor prior to installation into the hole.

FIG. 3 shows a cross section of an anchor made of smooth sheet metal.

FIG. 4 shows cross sections of an anchor made of rolled sheet with stiffening corrugations with their different locations.

FIG. 5 shows a general view of a tubular friction anchor complete with a support element made of sheet metal with stiffenings after installation in the hole.

Implementation of the utility model

The friction tubular anchor is a hollow metal tube 1 with a longitudinal slit 2 along the entire length, a support ring 3 welded at one end to hold the support element 4, characterized in that the anchor is made of sheet metal with pre-applied periodically repeated corrugations of stiffness 5 located transverse to the longitudinal axis of the anchor.

The technical result is also achieved by the fact that the anchor is made of sheet corrugated steel with a thickness of from 1.5 to 4.0 mm. The thickness of the sheet metal due to the stability of the anchor buckling. The thickness of the rolled less than 1.5 mm is not able to provide sufficient stability of the anchor to buckling, which leads to its bending during installation. The thickness of the steel more than 4.0 mm leads to an increase in metal consumption of the anchor, while its resistance to buckling becomes excessive.

The technical result is also achieved by the fact that the corrugations are made with a height of from 0.5 to 2.0 mm. When the thickness of the car is from 1.5 to 4.0 mm, the use of corrugations of stiffness with a height of less than 0.5 mm does not have a significant effect on the rigidity of the anchor, and when forming corrugations of stiffness with a height of over 2.0 mm, the discontinuity of the metal rolled in places of formation of corrugations.

The technical result is also achieved by the fact that the corrugations are made in widths from 2 to 10 mm. When the thickness of the car is from 1.5 to 4.0 mm, the formation of corrugations of stiffness with a width of less than 2 mm does not have a significant effect on the rigidity of the anchor; also during the formation of corrugations of stiffness of such a width, the discontinuity of the metal of the rolled metal in the places of their formation may occur. The formation of a corrugation of stiffness over a width of 10 mm and a height of 0.5 to 2.0 mm with a thickness of rolled metal of 1.5 to 4.0 mm does not have a significant effect on the rigidity of the anchor.

The technical result is also achieved by the fact that the distance between the tops of the corrugations of rigidity is from 2 to 60 mm. Since the corrugations of stiffness are symmetrical about their longitudinal axis, then with a width of corrugations of stiffness of 2 mm, the minimum distance between their tops will be 2 mm. Increasing the distance between the corrugations of stiffness above 60 mm with their height from 0.5 to 2.0 mm does not have a significant effect on the stiffness of the anchor.

These quantitative data were obtained as a result of research and development work at the plant OKS LLC and pilot tests at mines in Russia.

The installation of the anchor tube friction is as follows. After drilling the bore-holes, a boom with an adapter (punch) is installed on the boom of the feeder of the self-propelled drilling rig or on the hand drill. Next, the anchor of the tail part is put on the punch and installed in the guide (steady). The anchor element 4 is mounted on the anchor. The head end of the anchor 6 in the form of a truncated cone is inserted into the hole 7 of a smaller diameter than the diameter of the anchor and by the impact impact of the perforator on the tail part, the anchor is sent until the moment of the preloaded supporting element 4 of the rock mass 8.

During the installation of the anchor of the tubular friction in the hole, due to the high friction between the walls of the hole and the surface of the anchor, there are compression forces causing buckling of the anchor.

The technical problem to which the proposed utility model is directed, is the problem of the stability of a straight rod under the action of longitudinal compressive forces arising in the body of the anchor when it is installed in the hole.

As the load increases, due to an increase in the resistance of the anchor to blocking into the hole, arising due to the elastic deformations of the anchor body, the rectilinear shape of the metal anchor remains stable until a certain critical value of the load determined by the Euler formula is reached, after which the curved shape becomes stable, which is unacceptable during installation anchor hole, because leads to the impossibility of its further installation.

Euler's formula for determining the critical force:

где

Where

E is the modulus of longitudinal elasticity of the material;

J is the moment of inertia;

μ is the length reduction factor;

- длина стержня.

- rod length.

и Е являются одинаковыми в обоих случаях, а величина момента инерции J будет выше у анкера, изготовленного из гофрированного проката. Соответственно и величина критической нагрузки, вызывающей продольный изгиб анкера, у анкера из гофрированного проката будет выше, чем у анкера, изготовленного из гладкого проката. Это объясняется следующими доводами.In a comparative analysis of the prototype with the proposed utility model, made of the same material, the values of π, μ,

and E are the same in both cases, and the value of the moment of inertia J will be higher for an anchor made of corrugated steel. Accordingly, the magnitude of the critical load causing buckling of the anchor for a corrugated steel anchor will be higher than that of an anchor made from smooth steel. This is explained by the following reasons.

The moment of inertia of a thin-walled ring, which is the cross section of a tubular anchor, is determined by the formula:

J _x = J _y = πd ³ h / 8,

where d is the diameter of the ring (anchor);

h- wall thickness of the ring (anchor).

For clarity, we give the equation through the cross-sectional area of the ring (anchor).

J _x = J _y = πd ³ h / 8 = πd ² / 4⋅d⋅h / 2 = S⋅d⋅h / 2, where

S is the cross-sectional area of the ring (anchor).

An example of calculation.

FIG. 3 and 4 are cross-sections of anchors made of smooth and corrugated steel, respectively. Area S1 in FIG. 3 and 4 corresponds to the cross-sectional area of an anchor made from smooth steel; in FIG. 4 it is shown by a dotted line. Squares S2, S3 and S4 correspond to the cross-sectional areas of the anchor, made of corrugated steel at different locations of the corrugations. For comparison, a tubular anchor with a length of 2000 mm, an external diameter of 47 mm and a wall thickness of 2.5 mm, made of steel grade Art. 3 and calculated its cross-sectional area when used for the manufacture of smooth sheet metal and corrugated sheet metal. The calculations turned out that the cross sectional area of the anchor, made of smooth sheet metal is S1 = 241,773 mm ^2, and the cross-sectional areas of the anchor, made of corrugated rolled equal to S2 = 284,555 mm ² S3 = 300,712 mm ^2, S4 = 299,299 mm ² . Accordingly, the moment of inertia for a smooth rolled anchor will be:

J _x = J _y = 241.773⋅47⋅2.5 / 2 = 14204.163 mm ⁴

The moment of inertia for the corrugated anchor for the minimum cross-section is:

J _x = J _y = 284.555⋅47⋅2.5 / 2 = 16717.606 mm ⁴

From the above calculation it follows that the moment of inertia of an anchor from corrugated steel is 18% higher than that of an annealed steel. Accordingly, the critical force at which anchor bends when subjected to compressive forces will be 18% higher when using corrugated steel for the manufacture of an anchor.

The technical result, declared when applying for a patent for a utility model, is achieved by a combination of its essential features indicated in the formula. The significance of all features of the utility model is confirmed by the causal link between the features of the formula of the utility model and the technical result.

The friction tubular anchor, offered as a utility model, is a device, all of whose elements are interconnected and perform a single function.

The utility model meets the conditions of patentability "novelty" and "industrial applicability", which was confirmed in the course of research and development work, pilot tests in real conditions of mine workings.

Claims (1)

Friction tubular anchor, made in the form of a hollow metal tube with a longitudinal slit along the entire length, with a support ring welded at one end to hold the support element, characterized in that the anchor is made of rolled metal sheet with a thickness of 1.5 to 4.0 mm previously applied periodically repeating stiffening corrugations with a height of 0.5 to 2.0 mm, a width of 2.0 to 10.0 mm, the distance between the tops of the stiffening corrugations is from 2.0 to 60.0 mm, while the stiffening corrugations are transversely relatively longitudinal second anchor axis.

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