RU2006345C1 - Hot shears for rolled products of round and square cross section - Google Patents

Abstract

FIELD: mechanical engineering; metallurgy. SUBSTANCE: frame shaped knife holders 2, 3 provided with knives 4-7 are mounted within housing 1. The knives are rigidly kinematically connected with the double-throw crankshaft and throws 8, 9 via connecting rods 10 and 11. Knives 4 and 5 are connected with throw 8, and knives 6 and 7 - with throw 9. The shears have also roller conveyor 12, plates 13, and stop member 14 designed to fix the length of the cut part of billet 15. The size of the main shaft throw is dependant of the billet thickness and may be determined by the formula presented in the description. EFFECT: reduced quantity of waste material.

Description

 The invention relates to procurement in mechanical engineering and metallurgy and can be used for high-quality cutting of hot rolled products on measuring blanks non-waste method.

 Known scissors for hot cutting of long products, containing a fixed knife fixed in the body, and a movable knife mounted in a knife holder that performs translational movement in a vertical plane, directed perpendicular to the axis of the cut workpiece [1].

 Scissors provide a preliminary cut and the final cut of the workpiece from the profile.

 The disadvantage of these scissors is the design complexity, which consists in the fact that there is a clamping device for half-knife blades, as well as the limited length of the cut workpiece, due to the width of the movable knife.

 The closest solution to the technical essence of the achieved result to the invention are scissors for hot cutting of rolled round and rectangular cross-section, containing a bed, two knife holders installed in the bed with the possibility of reciprocating movement in the direction perpendicular to the axis of the cut steel, knives according to the number of knife holders, each of which is fixed in the corresponding knife holder and a crank mechanism for moving knife holders [2].

 The disadvantage of these scissors is the low quality of the end surface of the resulting workpieces, since with one-sided cutting, especially of highly plastic materials, an end bevel and burrs usually appear. The known design is complex, as it includes levers of the clamping device, in addition, the lower knife quickly wears out due to the action of high stresses and heating to higher temperatures compared with the upper knife.

 The technical result of the invention is to increase durability and improve the quality of the resulting products.

This is achieved by the fact that in scissors for hot cutting of rolled round and rectangular cross-section, containing a bed, two knife holders installed in the bed with the possibility of reciprocating movement in the direction perpendicular to the axis of the cut steel, knives according to the number of knife holders, each of which fixed in the corresponding knife holder, and a crank mechanism for moving the knife holder, each knife holder is made in the form of a closed frame and is equipped with an additional knife, knives in the knife holder Rep fixed on their internal surfaces in parallel pairs, and the shaft of the crank mechanism is configured dvuhkolennym, elbows which are arranged relative to one another at an angle of ¹⁸⁰ ° and associated with the respective knife carrier.

 In FIG. 1 shows scissors, general view; in FIG. 2 - frame-shaped knife holder; in FIG. 3 - kinematics of the cutting process; in FIG. 4 - the position of the shaft of the crank mechanism.

 In the case 1 mounted frame-shaped knife holders 2,3 with knives 4-7 placed in them, having a rigid kinematic connection with the two-crankshaft-knees 8 and 9 by means of rods 10 and 11. Knives 4 and 5 are connected to knee 8, and knives 6 and 7 - with elbow 9. There are also roller tables 12, wiring 13 and emphasis 14 for fixing the length of the cut part of the workpiece 15.

 The determining factor in the implementation of the reverse cutting process is the relationship between the distance between the knives installed in one knife holder and the radius of the corresponding elbow. The magnitude of the elbow of the main shaft depends on the thickness of the cut workpiece and can be determined as follows: from Δ AOW (Fig. 4).

r ₁ - Δh = r ₁ ˙cosα
whence r ₁ = Δh / (1-Cosα) = (εh) / (1-Cosα) where r ₁ is the radius of the crank;
h is the thickness of the cut steel;
ε is the relative depth of penetration of the knife;
α- permissible crank angle corresponding to the beginning of the stroke.

The distance between the knives installed in the same knife holder, and the distance of each of them in the initial position to the axis of supply of the rolled products and the radius of the elbow of the main shaft, the thickness of the cut workpiece and the penetration of the knife are interconnected by the following expression: l ₁₁ + l ₁₂ = L ₁ ;
l ₁₁ = r ₁ + (h / 2) -Δh ₁ ;
l ₁₂ = r ₁ + (h / 2) -Δh ₂ ; where L ₁ - the distance between the knives mounted on the same knife holders;
l ₁₁ , l ₁₂ - the distance from the front 4 and rear 5 of the knife to the feed axis of the rental in their original position;
Δ h ₁ , Δh ₂ - respectively, the introduction of the front 4 and rear 5 knives relative to the initial position of the cut workpiece.

The difference between l ₁ and l ₂ depends on the notch depth Δh.

If the value of the preliminary and final cut is equal, Δh ₁ = Δh ₂ , then l ₁₁ = l ₁₂ = l ₂₁ = l ₂₁ .

Similarly, the knee radius r ₂ and the distance between the knives L _{2 of the} second knife holder (L ₂ = l ₂₁ + l ₂₂ ) are also set.

Along with the value of the radius of the knee and the distance between the knives, the location of the knees in a vertical plane in the initial position at an angle of 180 ° ^to each other is essential and mandatory.

 Scissors work as follows.

 In the initial position of the knee 8 and 9 are located mutually opposite and lie perpendicular to the plane of the direction of cut. The workpiece 15 is fed along the rolling table 12 until it stops 14. After turning on the drive (not shown in the drawing), the rotation of the two-cranked shaft begins. Knee 8 and the associated knives 4 and 5 begin to move forward towards the workpiece. At the same time, the knee 9 and the knives 6 and 7 associated with it move back.

The paths of movement of the knives, indicated respectively by the indices 4 ¹ , 5 ¹ , 6 ¹ , 7 ¹ depending on the rotation of the crankshaft, are shown in FIG. 3. When the shaft is turned, when the distance between the knives 5 and 6 moving in opposite directions becomes equal to the width of the workpiece, the introduction of knives into the metal being cut begins. The process continues to the maximum approximation of these knives (section II of Fig. 3), which corresponds to the end of the preliminary cut in this direction (the workpiece is cut by 10-20% depending on the plastic properties of the metal). With further rotation of the 2-crankshaft, knives 5 and 6 diverge, and knives 4 and 7 begin to converge. The reverse is carried out, finally cutting the workpiece in the opposite direction. The process continues to their maximum approximation (section II-II of Fig. 3).

 In the described scissors, the reverse movement of the knives determines the cutting process in two stages - cutting the workpiece to crack formation in one direction and final separation in the same plane when the other pair of knives is reversed, which ensures the restoration of the dent formed in the first cutting stage, minimizes the formation of a face bevel and burrs. In addition, the tight pressing of the workpiece to the wires at the final cutting stage prevents its axial curvature, accompanying the open cutting process.

 The proposed design is much more perfect than the known one, since the use of one two-cranked shaft and frame-shaped knife holders with double-sided knives made it possible to carry out reverse cutting with one full revolution of the shaft. The intermittent, short-term contact of the knives with the metal being cut causes a decrease in their wear and increases durability. In addition, complex linkages are eliminated and the load on the bed of scissors is reduced due to the mutual balancing of the arising transverse forces.

The horizontal movement of the knives eliminates the need for a swinging table and a clamping mechanism, the purpose of which is fixed wiring, since horizontal reversing cutting ensures minimal movement of the cut parts and therefore their minimum bias (especially when cutting long workpieces). In this case, the guides 13 installed at a certain distance (depending on the cross section of the cut workpiece 10.000-1000.000 mm ² ) simultaneously perform the function of the clamps. In addition, at the last stage of cutting, the cutting knives 4 and 7 tightly press the workpiece to the corresponding wiring, straightening it in case of axial deflection. (56) 1. Japan Application N 55-36445, cl. In 23 D 15/04, 1980.

 2. Korolev A. A. Mechanical equipment rolling and pipe shops. M.: Metallurgy, 1987.

Claims (1)

SCISSORS FOR HOT CUTTING OF ROLLED AND RECTANGULAR CROSS SECTION, containing a bed, two knife holders installed in the bed with the possibility of reciprocating movement in the direction perpendicular to the axis of the cut metal, knives according to the number of knife holders, each of which is fixed in connecting rod mechanism for moving knife holders, characterized in that, in order to increase durability and improve the quality of the products obtained, each of the knife holders is made in in the form of a closed frame and is equipped with an additional knife, the knives in the knife holders are fixed in parallel on their inner surfaces, and the crank shaft is made of a two-knee, the knee of which is located relative to each other at an angle of 180 ^o and connected with the respective knife holders.

Images