SU984730A1 - Flying chkrs - Google Patents

Description

(54) VOLTAGE SCISSORS

The invention relates to the processing of metals by pressure, in particular, to flying shears for cutting sheet metal to dimensional lengths, and can be used in cutting machines, rolling mills, etc. The flying shears are known that contain a frame with supporting supports and lower blades. of which is associated with the eccentric drive shaft and has the ability to move along the vertical guides of another slide, made in the form of a carriage, having a reciprocating movement along the axis of the cut strip on roller guides. When the eccentric shaft is rotated, the caliper associated with it moves around the circumference described by the radius of the eccentricity. At the same time, the speed and movement of the caliper are decomposed into two components: the vertical one in the guide carriages of the other caliper and the horizontal one, together with the carriage with reciprocating movement 1 and 2. The disadvantage of these scissors is the low speed due to the presence of flywheel masses reciprocating movement, as well as the lack of feed to the cut of one of the knives, which leads to an increase in the angle of capture when cutting wide thick strips. Flying shears are known that contain two main eccentric drive shafts and knives with supports, which are connected by guides 3. Known flying shears have the following disadvantages: the high intensity of the flying shears for cutting thick wide strips; the drive of both supports is common, which does not allow expanding the technological capabilities when cutting; There is a significant dynamics when cutting thick strip steel at high speeds, which leads to increased wear and failure of flying scissors components and parts. The purpose of the invention is the expansion of technological capabilities by providing cutting of rolled strip of various thickness. The goal is achieved by the fact that the flying shears, containing two main eccentric drive shafts and knife supports, are interconnected by guides, are equipped with an additional eccentric shaft, one of the calipers is mounted on said shaft, and the other support is mounted on two main identical eccentric shafts .

The additional eccentric shaft is supplied with an individual drive.

FIG. 1 shows the kinematic diagram of the flying shears; in fig. 2 - side view of scissors; in fig. 3 shows the trajectories of the movement of the calipers with knives for various scissors designs.

The flying shears contain an upper caliper 1 with a knife 2, made in the form of a frame pivotally mounted on the necks of eccentric shafts 3 and 4 and having inside guides 5 and 6 for the lower caliper 7 with a knife 8 mounted by means of shatuni 9 and 10 pivotally on the necks of an eccentric shaft 11, general drive 12 connected to the eccentric shafts of the upper caliper by gear 13 and to the eccentric shaft of the lower caliper by the coupling 14, individual drive 15 connected to the eccentric shaft of the lower caliper by the coupling that 16 ..

Flying scissors work as follows.

The rotation drive of the eccentric shafts of the calipers may be common or separate, individual for each caliper.

In general, the rotational drive of the eccentric shafts, the coupling sleeve 14 is closed, the coupling sleeve 16 is open.

The initial position - the knives are divorced, i.e., the eccentrics of the shafts 3 and 4 of the upper support 1 are located in the upper position, the eccentrics of the shaft 11 of the lower support 7 - in the lower position.

The actuator 12 by means of a gear 13 of the coupling 14 rotates the eccentric shafts of both calipers, while the caliper 1 with the knife 2 moves described in absolute circular motion, and the caliper 7 with the knife 8 circular, elliptical or complex trajectories (Fig. Over, 6,8) depending on the magnitude of the eccentricities of the shafts 3 ,. 4 and gear ratio 13.

The supports 1 and 7 with the knives 2 and 8 in reciprocal movement perform reciprocating movement and constantly take a position perpendicular to the direction of movement of the strip. With this kinematic scheme of flying shears, the horizontal speed of the knives is provided by the upper support (frame). When the eccentrics of the shafts 3 and 4 are in the lowest position, and the shaft 11 in the extreme upper position, the supports 1 and 7 with the knives 2 and 8 approach each other, and the rolled strip is cut.

The eccentricity of shafts 3 and 4 may be equal to or different in magnitude from the eccentricity of the shaft 11.

With equal eccentricities of eccentric valbv upper and lower calipers

(ez) the gears in gear 13 have the same diameters of the pitch circles (da, dJ2 dj-), and for one full turn of the drive each caliper moves from one extreme position to the other and back, while the trajectories of the blades of both calipers are circular (FIG. Over) and their radius is equal to the magnitude of the eccentricity.

With different eccentricities of the shafts of the upper and lower calipers (ei ei

2; a) gear wheels in a gear can have both the same and different diameters of the pitch circles. If the diameters of the pitch circles of all gears are the same (dj ,, () then, as in the previous case,

in one turn of the drive, the calipers make one-time reciprocating / strokes, but the path of movement of the upper knife will be circular and the lower one - elliptical (Fig. 36).

5 If the diameters of the pitch circles of the gears on the shafts 3 and 4 are larger than on the shaft 11 (d3, d3j;,), then in one revolution of the eccentric shafts 3 and 4, the shaft 11 will make several turns, the number of which is determined by the gear ratio of the gears and

The trajectory of the upper knife in this case will also be circular, and the lower one - a complex curve, for example, with respect to ds, 5 3d32, the trajectory represents the similarity of two eights (Fig. 3).

An analysis of the trajectories of movement of the knives of the upper and lower calipers shows that the smallest angle of the gripping strip is obtained when the circular trajectory of the upper and complex trajectory of the lower knife. However, there is a drawback in this scheme, which is that with a common drive for one stroke of the upper caliper, the lower caliper makes multiple strokes, each time it touches the strip with a knife and thereby degrades the quality of its surface. To eliminate this phenomenon, it is necessary to provide special wiring to maintain the strip above the upper position of the lower knife until the beginning of the cut, which complicates the design of the scissors as a whole, or use an individual drive rotation of the eccentric shafts of each caliper.

With a separate drive of the calipers, it becomes possible to obtain the smallest angle of the strip to be captured by the upper caliper, i.e., to obtain the middle part of the complex trajectory (Fig. 3s) in one stroke of both calipers.

With a separate caliper drive, the eccentric shafts 3 and 4 receive rotation from the drive 12, and the eccentric shaft 11 from the drive 15. The coupling sleeve 14 is open and the coupling 16 is closed. The original position of the calipers is the same as in the case with the general drive.

Scissors work as follows.

The actuator 12 rotates the eccentrics of the UH shafts 3 and 4, the upper caliper with the knives 2 begins to move along a circular path. After a certain time, taking into account the time taken to accelerate the system, the drive 15 of the lower caliper is activated so that the knives of both calipers approach the strip at a given gripping angle at the same time.

The motion path of the lower support with the knife also represents a complex curve (Fig. Ze), but it was obtained in one turn of the lower support. As mentioned earlier, this combination of circular and complex trajectory of the knives leads to a decrease in the angle of capture of the strip by knives, which makes it possible to cut thick rolled strip with a slight difference between the horizontal speed of the knives and the strip.

Making eccentric flanks of the lower caliper with an eccentricity less than the eccentricity of the shafts of the upper caliper allows it to accelerate at a much higher speed than the upper caliper in a shorter time and with lower drive power.

In this case, the total power of the drives decreases, since the power required for the separate acceleration of the upper and relatively small mass of the lower caliper is less than the power required for acceleration of the shears as a whole for each cut. The design of the flying scissors allows to ensure high quality of the cut, reduce the metal intensity of the scissors, reduce the power of the drives, and expand the technological capabilities when cutting wide strip steel of various thicknesses.

Claims (3)

1.Flying scissors, containing two main eccentric drive shafts and knife supports, interconnected by guides, characterized in that 5 with the aim of expanding technological capabilities by providing cutting of rolled strip of various thickness, they are equipped with an additional eccentric shaft, one of the supports on the specified shaft, and the other support is mounted on two 0 main identical eccentric shafts. 2. The shears according to claim 1, which are characterized by the fact that the additional eccentric shaft is provided with an individual drive. Information sources, 5 taken into account in the examination 1.Reznichenko, AI and others. Modern designs of flying knives for dimensional cutting of broadband steel in the USSR and abroad. M., NIIINFORMTYAZHMASH, 0 1972, -72-20, p. 50. 2. Popov B.V. et al. New flying shears for cutting broadband steel. M., NIIINFORMTYAZHMASH, 1973. 1-73-55, p. 1-4. 3. USSR author's certificate 5 No. 599933, cl. In 23 D 25/10, 1976 (prototype).