RU2096139C1 - Shears for cutting sheet material - Google Patents

Abstract

FIELD: plastic metal working. SUBSTANCE: shears has bed 1 with table 2, knife 3 fixed to the table, slide 4 with top knife 5, drive 6 for moving the slide, and device 17 for changing an angle of inclination of the top knife 6 to the bottom one made up as a replaceable cell of Z-shaped cross-section 18, mounted on slide 4. The bearing surfaces of cell 18, which are in a contact with slide 4 and knife 5, are at an angle to each other that defines the inclination of top knife 5 to bottom knife 3. EFFECT: enhanced efficiency. 2 dwg , 1 tbl

Description

 The invention relates to the processing of metals by pressure, in particular to devices for cutting metal, and can be used for cutting sheet metal.

Known scissors for cutting sheet material containing a bed with a table on which a fixed lower knife is fixed, a slider with an upper knife and a slider drive with an upper knife, made in the form of a crank mechanism [1]
Scissors do not contain a mechanism for changing the angle of inclination of the upper knife relative to the lower, depending on the thickness of the cut sheet material. When cutting sheet material, the cut part bends with a bulge towards the inclined knife. Sheet material with a bend in the cutting zone is subject to editing.

Known scissors for cutting sheet material containing a bed with a table on which a fixed lower knife is fixed, a slider with an upper knife and a drive for moving the upper slider with the upper knife [2]
Scissors do not contain a mechanism for changing the angle of inclination of the upper knife with respect to the lower. When cutting sheet material, bending of the cut part also occurs.

кривизна вогнутости;
στ предел текучести разрезаемого материала;
E модуль упругости разрезаемого материала;
h толщина разрезаемого материала.To correct a defect in the form of a bend, the scissors are equipped with a housing located on the side of the cut sheet part and mounted on the bed with vertical guides and movably arranged in the said guides by a table with a drive mounted for rotation in a plane perpendicular to the material supply axis, while the table surface is on the side the cut part of the sheet at the upper position of the knife beam is located at the same level with the cutting edge of the lower knife. The surface of the table is made concave with curvature determined by the ratio

concavity curvature;
στ yield strength of the material being cut;
E is the elastic modulus of the material being cut;
h is the thickness of the material being cut.

 The cut part of the sheet after bending with the upper knife abuts against the table surface and undergoes editing.

 The disadvantage of this invention is that for different thicknesses and mechanical properties of the material being cut, its own profiling of the table surface is required, i.e. the table should be replaceable. And since the table is under the slider, replacing it is very time-consuming. In addition, the presence of a table directly under the slider makes it difficult to remove scraps of sheet during operation.

 Known closest to the proposed scissors for cutting sheet material, containing a bed with a table on which a fixed knife is mounted, mounted with the ability to move the slider carrying the upper knife, the drive moving the slider and a device for changing the angle of inclination of the upper knife relative to the lower knife.

The device for changing the angle of inclination of the movable knife includes an indicator, which through the fist and flexible tape controls the vertical movement of the control valves in opposite directions. The latter control the jacks acting on the ends of the knife [3]
A device for adjusting the angle of inclination of the movable knife of known scissors is complex in design and has low reliability, since the presence of control valves involves their positioning in different positions when the angle of inclination of the movable knife changes. The presence of such control valves in the circuit places an increased demand on the filtration of the working fluid. When working according to this scheme, as a result of leakage of the working fluid, a spontaneous change in the angle of inclination of the knife is possible.

 The aim of the invention is to expand the technological capabilities of scissors and improve the quality of the sheet in flatness, reduce the cost of correcting defects in flatness, and in accordance with the stated increase in production on the sheet finishing lines.

 This goal is achieved by the fact that scissors for cutting sheet material containing a bed with a table on which a fixed lower knife is mounted, movable with a slider carrying the upper knife, the slider moving drive is equipped with a device for changing the angle of inclination of the upper knife relative to the lower knife, made in the form of a removable cartridge of a Z-shaped section mounted on a slider, while the supporting surfaces of the cartridge, designed to interact with the slider and the upper knife, are made at an angle between oh, determining the angle of inclination of the upper knife relative to the lower knife.

 In FIG. 1 shows a General view of the scissors for cutting sheet material, front view, figure 2 section aa.

 Scissors for cutting sheet material contain a frame 1 with a table 2, on which a fixed lower knife 3 is mounted, mounted with the ability to move the slider 4, carrying the upper knife 5, the drive 6 for moving the slider 4, made in the form of a crank mechanism 7, including an electric motor 8 , gear 9, a pair of gears 10, 11, a crankshaft 12, connecting rods 13, 14 and hinges 15, 16 of the slider suspension 4.

 The scissors are equipped with a device 17 for changing the angle of inclination of the upper knife 5 relative to the lower knife 3, made in the form of a removable cartridge 18 Z-shaped section mounted on the slider 4.

 A groove 19 is made in the cassette 18 for attaching the upper knife 5. The replaceable cassette 18 is fixed to the slider 4 with bolts 20, and the upper knife 5 is fixed to the cassette 18 with bolts 21. In this case, the supporting surface 22 in contact with the slider 4 and the surface 23, in contact with the knife 5, are made at an angle b between themselves, which determines the angle a of the inclination of the upper knife 5 with respect to the lower knife 3.

где

угол между опорными поверхностями 22 и 23 нижнего 3 и верхнего 5 ножей.Wherein

Where

the angle between the supporting surfaces 22 and 23 of the lower 3 and upper 5 knives.

.In the case of parallelism of the supporting surfaces 22, 23 among themselves

.

 Replaceable cartridge 18 is fixed in the groove 24 on the slider 4, while the cartridge 18 with its supporting surface 22 is in contact with the bottom 25 of the groove 24, and a gap d is established between the opener 26 of the cartridge 18 and the slider.

 Scissors work as follows.

 The sheet is defined between the fixed lower knife 3 and the movable upper knife 5. When the motor 8 is turned on, the crankshaft 12 of the crank mechanism 7 rotates and moves the slider 4 in the bed 1 of the scissors.

 In this case, the sheet is cut between the upper 5 and lower 3 knives. Since the upper knife 5 is installed at an angle a with respect to the lower knife 3, bending of the cut part of the sheet occurs as a result of tangential stresses in the sheet from the impact of the knife.

 To reduce the deflection of the sheet from the influence of tangential stresses in the cutting zone, a replaceable cartridge 18 is installed on the slider 4, in which the supporting surfaces 22, 23 in contact with the knife 5 and the bottom 25 of the groove 24 of the slider 4 are made at an angle b that defines the angle a of the tilt of the upper knife 5 with respect to the lower knife 3.

,
где α_i угол между верхним и нижним ножами,
h_i толщина разрезаемого листа,
h_max максимальная толщина разрезаемого листа,
α_max угол между верхним и нижним ножами при разрезании листа с максимальной толщиной.The angle a is determined from the relation

,
where α _{i is the} angle between the upper and lower knives,
h _{i the} thickness of the cut sheet,
h _{max the} maximum thickness of the cut sheet,
α _max angle between the upper and lower knives when cutting a sheet with maximum thickness.

 A set of interchangeable cartridges with different angles β between the supporting surfaces 22, 23 is made for scissors.

 When cutting, the force from the upper knife 5 is transmitted to the supporting surface 23 of the cartridge 18, and then to the bottom 25 of the groove 24 of the slider 4. The shear force arising from the cutting is transmitted to the side surface of the groove 24 of the cartridge 18, and then through the opener 26 of the cartridge during deformation and choosing a clearance d on the slider 4.

 The angle b between the supporting surfaces 22, 23 of the removable cartridge 18 is set from the condition for choosing the required angle a of the inclination of the upper knife 5 with respect to the lower 3, at which the bending of the cut part of the sheet is insignificant for a certain range of thicknesses of the material being cut and fits into the flatness tolerances required by standards and the customer to the sheets in the cards.

 Studies were conducted to determine the optimal angle of inclination of the upper knife 5 with respect to the lower 3 guillotine shears with a force of 600 tons of cutting line of the plate mill 2800 of Severstal JSC.

 The research results are summarized in table.

The research results show that for the thicknesses of the cut sheet in the ranges of 8.19 and 19.25 mm, it is preferable to use the angle a of the inclination of the upper knife with respect to the lower in the range close to the angle 1 ^o 55 '. In this case, the deflection of the cut sheet meets the increased requirements of the customer (6 mm or less / 1 linear meter). Sheets 25.32 and 32.50 mm thick on scissors were not processed due to insufficient cutting force. For thicknesses of the cut sheet 25.32, it is preferable to use an angle a close to 2 ^° 30 ′.

 In this case, the deflection of the sheet does not exceed the permissible limits (12 mm / 1 linear meter) specified by the standard.

For sheets 32.50 mm thick, it is preferable to use an angle a close to 5 ^° 45 '.

 When working for a batch of metal with a certain thickness and mechanical properties, a cassette is installed on the slider of 4 scissors, at which the angle b between the supporting surfaces 22, 23 corresponds to the necessary angle a, at which the deflection of the sheet during cutting does not go beyond the tolerances specified by the order.

Claims (1)

 Scissors for cutting sheet material containing a bed with a table on which a fixed lower knife is mounted, movable with a slider carrying the upper knife, a slider moving drive and a device for changing the angle of inclination of the upper knife relative to the lower knife, characterized in that the device for changing the angle of inclination the upper knife is made in the form of a removable cartridge of a Z-shaped section mounted on a slider, while the supporting surfaces of the cartridge, designed to interact with the slider and the upper knife, are Full angle between themselves defining an angle of inclination of the upper knife relative to the lower knife.

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