RU2354512C1 - Cutting method of long-length sheet material and related device - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: inventions consider pressurised metal treatment and may be used in machine building industry for rolled metal cutting in cold and semi-cold states. During cutting, the being cutoff part of separated sheet is forcibly deformed in the area of maximum static deflection of its centre of gravity towards the main motion of inclined throat shears. It is deformed within the limits of material elasticity and proportionally to the cutting length by the value no less than static deflection of being cutoff part centre of gravity under proper weight effects using retractable and adjustable by height stops. The device is mounted on the frame of descending shear table and implemented as stopper arms which are hinge connected with load-bearing bar by means of adjustable by length links. The load-bearing bar is fastened to the shear foundation. Stoppers are installed horizontally in the area of maximum static deflection of the being cutoff part of the sheet and at a distance from the cutting shear edge being no more than half of the above part. The stoppers are also installed vertically above cutting edge of inclined throat shears at the lower position of the main motion and descended table by the value no less than static deflection of the being cutoff part of the sheet under the proper weight effect.

EFFECT: improved quality of separated sheet cutting.

3 cl, 6 dwg,1 ex

Description

The invention relates to the processing of metals by pressure and can be used in mechanical engineering and in the metallurgical industry for cutting sheet metal in cold or semi-cold conditions.

Scissors with a top cut, usually with an inclined knife, are used in the rolling industry of the metallurgical industry. The lower scissor knife is usually set horizontally. The angle of inclination of the upper knife is selected depending on the mechanical (strength) properties of the material being cut and its thickness in order to reduce the metal consumption of the machine and the drive power. [Encyclopedic reference book, vol. 8, M., "Mashgiz", 1949, p. 721, UDC621 (03), M38].

The disadvantages of scissors with inclined knives include bending with an inclined knife the edges of the sheet when cutting [Encyclopedic Handbook, Vol. 8, M., Mashgiz, 1948, p. 721, p. 968, UDC621 (03), M38].

Bending the edge of the sheet during cutting leads to an increase in deviation from flatness. The quality of rolled products is regulated by state standards, including the type of flatness.

Depending on deviations from flatness per 1 m of the length of rolled products supplied in sheets, for example GOST 19903-74 “Hot-rolled sheet steel”, norms are determined by the types of flatness. Types of flatness determine the quality of products and, consequently, the price. When studying the cutting process with an inclined knife, it was found that the total force required to cut the sheet with an inclined knife is composed of two main quantities: the intrinsic cutting force necessary to overcome the shear resistance of one part of the sheet relative to the other, and the effort required to bend the sheet arising when cutting with an inclined knife.

The amount of bending of the edge of the cut part of the sheet at the initial moment of cutting is well known and depends on the angle of inclination of the knife, the thickness of the sheet, and the mechanical properties of the material of the cut sheet.

A device for guillotine shears for trimming the longitudinal edge of the sheets (ed. Certificate of the USSR No. 137379, 6 V23B 15/06, published in the "Bulletin of inventions" No. 7 for 1961).

The known device is made in the form of a lowering stop mounted on the side of the scissors along the sheet supply, under the cut edge for the purpose of reverse bending under the action of an inclined scissor knife.

The use of a known device for transverse cutting of a sheet is impossible, because the length of the shear knife for transverse cutting is greater than the width of the shared sheet and the design of the known scissors with an inclined knife does not allow sequential cutting in the transverse direction of sheets of large length.

In addition, it is known that when cutting steel by transverse cutting with an upper cut with an inclined knife, during cutting of a sheet, not all the cross-sectional area of the sheet is subjected to cutting at the same time, but only part of it, which appears to be a triangle during the steady-state cutting process [Encyclopedic Handbook, Vol. 8, M., Mashgiz, 1949, p. 969, UDC621 (03), M38].

During the transverse cut of the sheet, the length of the cut increases, and the remaining uncut part of the sheet decreases. The bending of the edges (edges) of the sheet when cutting with an inclined knife is directed towards the longitudinal axis of the cut part of the sheet.

The present invention solves the problem of improving the quality of the cut of the cut part of the shared sheet during cutting.

Improving the quality of the cut is achieved by reducing the bending of the sheet edge at the final moment of cutting (at the end of the cutting process) of the sheet.

To obtain such a technical result, in the proposed method for improving the quality of cut of sheet material, mainly long one, with scissors with an upper inclined knife, the cut part of the shared sheet during cutting is forcibly deformed in the region of maximum static deflection within the elasticity of the sheet material towards the working movement of the inclined knife. They deform within the elasticity of the material of the cut part of the sheet being divided in proportion to the length of the cut by an amount not less than the static deflection of the center of gravity of the cut part of the sheet under the action of its own mass by means of retractable, height-adjustable stops with rotating rollers.

Distinctive features of the proposed method are forced deformation in the region of maximum static deflection of the cut part of the shared sheet towards the working movement of the inclined knife, taking into account the course of the inclined knife in the plane of the stops, by at least a static deflection of the center of gravity of the cut part of the divided sheet.

This allows you to reduce the bending of the edge of the cut part of the sheet at the final moment of cutting (at the end of the cut).

When practicing the proposed method, it was found that the bending of the edge of the cut part of the sheet at the initial moment of cutting with an inclined knife is well known and consists of two main quantities: the intrinsic cutting force and the effort spent on bending the sheet that occurs when cutting with an inclined knife [Encyclopedic Handbook, vol. 8, M., "Mashgiz", 1949, p. 969, UDC621 (03), M38].

The value of the bend of the edge of the cut part of the sheet to be cut at the end of the cut (at the final moment of cutting), especially when cutting sheets with a thickness of more than 16 mm - 20 mm and a length of more than 1500 mm - 2000 mm, begins to significantly exceed the absolute value of the bend of the edge of the cut part of the sheet to be cut at the beginning of the cut (at the initial moment of cutting).

It is established that at the end of the cut, the forces that deform the uncut part of the cut sheet, from the intrinsic mass of the cut part of the sheet, are added to the well-known effort spent on bending the sheet that occurs when cutting with an inclined knife.

During the transverse cut of the sheet, the length of the cut increases, and the remaining uncut portion of the cross section of the sheet decreases. Before the cut, the entire mass of the cut part of the sheet, like beams with freely supported edges, is evenly distributed over the cross-sectional area in the plane of the supports (on the one hand on the bottom knife of the scissors, and on the other on the receiving roller of the rolling mill or the falling table).

In the process of cutting, the cross-sectional area of the uncut part in the plane of the cut of the sheet decreases, therefore, the deformation forces along the time of cutting for the remaining undercut part of the sheet are constantly increasing.

There comes a time when the rate of bending deformation from the sheet own mass exceeds the deformation from the cutting forces in magnitude. The value of the bend of the edge of the sheet in this case significantly exceeds the value of the bend of the edge of the sheet at the initial moment of cutting the sheet.

In contrast to the known device according to USSR author's certificate No. 137379, the proposed method of forced deformation in the region of maximum static deflection of the cut part of the shared sheet towards the working movement of the inclined knife, taking into account the course of the latter by the amount of no less than the static deflection of the center of gravity, excludes the component of the residual deformation bending of the sheet edge from its own mass of the cut part of the shared sheet.

To achieve the named technical result, a device is proposed which, like the closest known to it according to the USSR author's certificate No. 137379, contains retractable stops with rollers rotating around their own axes.

In contrast to the known retractable stops of the proposed device are mounted on the frame of a descending scissors table for transverse cutting of rolled products in a sheet-rolling workshop between chains of a multi-row chain conveyor in the form of levers of at least two kinematically connected articulated by length-adjustable links with a power beam fixed to the scissors foundation .

The stops are equipped with rollers with the possibility of rotation around their own axes, each in the horizontal (in the direction of rolling) direction in the region of maximum static deflection of the cut part of the sheet being shared, i.e. at a distance from the cutting edge of the lower knife of the scissors, not more than half the length of the cut part of the sheet. In the plane of rotation of the levers, each rotating roller is installed above the cutting edge of the inclined scissors knife with the lower position of the working stroke of the latter and with the table lowered by at least the static deflection of the center of gravity of the cut part of the sheet under its own weight.

The proposed design described was tested in sheet rolling shop No. 1 of OJSC "AMET". Installing retractable stops on the frame of the lowering table in the area of maximum static deflection of the cut part of the sheet, and not under the cut edge, as in the prototype according to ed. witness USSR No. 137379, and the forced deformation of the cut part of the sheet towards the working movement of the tilt knife allowed to significantly reduce the bending of the sheet edge (edge) during cutting. The actual deviations from flatness before the introduction of the proposed device corresponded to the normal type of flatness according to GOST 19903-74 "Hot-rolled sheet steel", and after the introduction of the inventive device to a high view of flatness according to GOST 19903-74.

The invention is illustrated by drawings, which depict:

figure 1 - diagram of a device for implementing the proposed method, top view;

figure 2 is a lowering table, a view along section AA in figure 1.

The proposed method is carried out in the following sequence.

Based on the geometric dimensions of the cut part of the sheet to be separated (thickness, width and length) and mechanical characteristics (density and elastic modulus) is determined by well-known formulas of material resistance by calculating the value of the static deflection of the center of gravity of the cut part of the sheet, as a freely supported beam. Almost without calculations, this value can be obtained by measuring the deflection arrow in the center of gravity of the sheet before the start of the cut.

Next, the position of the cutting edge of the upper inclined knife of the scissors is determined by calculation in the plane of each retractable adjustable stop at the lower position of the working stroke of the upper inclined knife relative to the cutting edge of the lower knife of the scissors. Practically, without calculations, these values can be obtained by measuring the distances from the cutting edge of the lower knife to the position of the cutting edge of the upper inclined knife in the extreme lower position of the working stroke (at the end of the working stroke). These measurements must be made in the planes of movement of the retractable stops.

Having these data, each stop is advanced in the vertical direction, increasing the length of the corresponding link connecting the stop lever to the power beam fixed on the scissors foundation so that the cylindrical surface of the roller mounted on the lever is higher than the calculated position of the cutting edge of the upper inclined scissors knife at the extreme lower position of the working stroke by the calculated value of the static deflection of the center of gravity of the cut part of the sheet.

When cutting the sheet by the claimed method, the sheet material is forced to deform towards the working movement of the inclined knife within the elasticity of the material of the divided sheet and the component of the residual deformation of the sheet edge at the end of the cut is excluded under the influence of the dead weight of the cut part of the sheet and, as a result, the absolute value of the deformation residual bending is significantly reduced the edges of the sheet during the cutting process, especially at the end of the knife stroke. The proposed method is more accurate than known by the USSR copyright certificate No. 137379, 6 B23D 15/06, because during the cut during the working movement of the upper inclined knife, the sheet under its action does not receive an inverse residual deformation anti-bending, which worsens the quality of the cut.

Example.

It is necessary to carry out the cutting of cold rolled steel with a thickness of 0.030 m, a width of 2.0 m on sheets with a length of 4.0 mm on scissors 1 with an upper inclined knife 2 (Fig. 1 and Fig. 2).

We determine the value of the static deflection of the center of gravity P of the cut-off part as a freely supported beam according to FIG. 3.

For a sheet of given geometric dimensions and material, this value (static deflection under the action of its own mass) is 0.157 m.

The value of static deflection can be calculated using well-known formulas of material resistance.

Turning on the drive of the upper knife, lower the upper inclined knife 2 to its lowest position.

We note the position of the cutting edge of the upper inclined knife 2 (points K, L, M) at the end of the lower knife 3 in the plane of rotation of the stops 4 (see Fig. 4 - Fig. 6).

We extend each stop 4 in the vertical direction (up) by the previously defined value P of the static deflection (Fig. 3) for a sheet of predetermined geometric dimensions and material, i.e. 0.157 m above the corresponding points K, L, M (Fig. 4 - Fig. 6) with the lowered position of the lowering table 5 without taking into account the rigidity of the stops 4.

Given the rigidity of the stops 4, the magnitude of their extension in the vertical direction exceeds the value P of the static deflection by the amount of flexibility of the stops 4 by the action of the mass of the cut part of the sheet. The extension of the stops 4, taking into account the flexibility of the stops, leads to an additional decrease in the amount of bending of the edge of the cut part of the sheet during cutting.

When cutting a sheet, the lowering table 5 occupies the position depicted in figure 4 - figure 6. The stops 4 should be placed relative to the cutting edge of the knife 3 in the horizontal direction in the region of maximum static deflection, in this case, at a distance of not more than half the length of the cut part of the sheet, i.e. at a distance of less than 2.0 m.

We feed the cut part of the rolled product to the lowering table 5 by the required amount, in this case, 4.0 m relative to the cutting edge of the lower knife 3 in a given direction and perform cutting.

During the cutting process, the cut part of the shared sheet is forcibly deformed by the stops 4 within the elasticity of the material, without residual deformation, towards the working movement of the tilt knife 2, as a result, the residual deformation (bending) of the sheet edge under the influence of the dead weight of the cut part of the shared sheet is excluded. The quality of the cut increases sharply.

The proposed device for improving the quality of the cut of sheet material with scissors 1 with an upper inclined knife 2 (Fig. 1 and Fig. 2) and a lower horizontal straight knife 3 contains stops 4 in the form of pivoting levers mounted on the frame of a table 5 with a lever system that lowers during cutting weightlessness 6 own weight.

The lowering table 5 of scissors 1 with the upper inclined knife 2 has an electric drive for raising and lowering, kinematically connected with the drive of the knife 2 of the scissors 1, a multi-row chain conveyor 7 for removing the cut part of the sheet from the cutting zone. On the frame of the lowering table 5 between the chains of the multi-row conveyor 7, the stops 4 are mounted pivotally in the form of levers.

The levers of the stops 4 are kinematically connected pivotally by means of links 8, adjustable in length, with a power beam 9, mounted on the foundation 10 of the scissors 1.

The stops 4 are provided with rollers 11 for rotation around their own axes.

The stops 4 are mounted relative to the cutting edge of the knives 2 and 3 of the scissors 1 at a distance of not more than half the length of the cut sheet (figure 4 - figure 6).

In the vertical plane (in the plane of rotation of the levers of the stops 4), the rollers 11 of each stop 4 are mounted so that the cylindrical generators of the rollers 11 in contact with the surface of the cut sheet are higher than the cutting edge of the upper inclined knife 2 by the value of the static the deflection of the center of gravity of the cut part of the sheet under the action of its own mass with the lowered position of the table 5 (figure 4 - figure 6).

Adjusting the position of the rollers 11 of the stops 4 relative to the cutting edge of the upper knife 2 in this case is carried out by changing the length of the links 8 by the required amount.

Figure 4 - figure 6 shows the position of the rollers 11 of the stops 4 relative to the cutting edge of the upper inclined knife 2 with the table lowered 5.

Figure 2 shows the rollers 11 of the stops 4 relative to the lowering table 5 in the initial (horizontal) position of the latter.

The device operates as follows.

The sheet to be cut is fed between the knives 2 and 3 of the scissors 1 onto the lowering table 5 for cutting (FIG. 2).

When cutting the cut part of the sheet, the lowering table 5 and the sliding stops 4 in the form of levers with rollers 11 occupy the position shown in Fig. 4 - Fig. 6.

After the cuts of the sheet, the table lift drive returns the table 5 to the horizontal position (FIG. 2). Chain multi-row conveyor 6 removes the cut part of the sheet from the cutting zone.

Next, the cutting cycle is repeated.

Claims (2)

1. A method of cutting a long sheet material with scissors with an upper inclined knife, characterized in that during the cutting process, the cut part of the sheet material is forcibly deformed in the region of its maximum static deflection towards the working movement of the upper inclined knife within the elasticity of the sheet material in proportion to the length of the cut by an amount not less than static deflection of the center of gravity of the cut part of the sheet material under the action of its own mass, while the deformation is carried out by izhnyh vertically adjustable stops rotating rollers with the magnitude of the stroke of the upper blade inclined in the plane of these stops. 2. A device for cutting long sheet material with scissors with an upper inclined knife, containing a foundation, a lower scissor knife mounted on it, an upper inclined knife drive, a table with a raising and lowering drive during cutting and with a lever weightless weight system kinematically connected to the drive upper inclined knife, and a chain multi-row conveyor for removing from the cutting zone the cut part of the sheet material, characterized in that it is provided with at least two stops in the form of levers, hinges mounted on a table frame between chains of a multi-row conveyor and pivotally connected by means of length-adjustable links with a power beam fixed to the foundation, rollers are mounted on the free ends of the levers with the possibility of rotation around their own axes from the condition that each of them is located in a horizontal plane at a distance from the cutting edge of the scissors, not exceeding half the length of the cut part of the sheet material, and in the plane of rotation of the levers - above the cutting edge of the upper inclined knife of the sheath n in its lowermost position by an amount not less than the static deflection of the center of gravity of the cut portion of the sheet material by its own weight when lowered position table.

Images