RU2336964C1 - Drawbench on moving mandrel - Google Patents

Abstract

FIELD: mechanics.

SUBSTANCE: drawbench on moving mandrel incorporates a loading bench, a working bench, rolls arranged on the drawbench inlet side, a prop of dies, pipe drawing mechanism, a pipe stop mechanism, a drawing carriage, a main drive with drive chains fitted on the working bench and a mandrel feed-and-withdraw mechanism arranged on the drawbench inlet side and comprising a mandrel gripper and a drive drum. The branches of the forward-back drives are laid on the drive drum in opposite directions. The back-drive cable is connected to the mandrel gripper via a tensioning device, while the forward-drive cables are thereto via the reversing blocks arranged on the die prop.

EFFECT: higher reliability, simpler design, expanded performances.

3 dwg

Description

The invention relates to the field of metal forming, in particular to pipe-drawing production.

Known mill for drawing pipes on a long (movable) mandrel (AS USSR No. 1002065, publ. 07.03.83, B.I. No. 9). According to this invention, the construction of the mill comprises two parallel chain conveyors (upper and lower), through which a movable mandrel with a pipe mounted on it is pushed through the die. After the die is installed a device for running the pipe and extracting the mandrel. Next, the mandrel is shifted in the transverse direction relative to the axis of the drawing and the roller conveyor is transferred to the input side of the mill on the loading table. Thus, the mandrel makes a working stroke, followed by an idle stroke along the entire length of the mill for feeding it to the load. The disadvantages of this design are the presence of idling of the mandrel, the lengthening of the drawing cycle and, as a result, the decrease in productivity of the mill due to the increased movement of the mandrel. In addition, the mechanisms of the mandrel moving transverse relative to the axis of drawing are needed and the roller conveyor drive mechanisms transporting the mandrel to the loading side after the drawing is completed, which reduces the reliability of the whole mill structure.

A known construction of a mill for drawing on a movable mandrel (Italian patent IT 119086 from 02.24.1988). A drawing mill stretching the pipe using a long mandrel is included in the production line comprising a loading table, a mechanism pushing the mandrel and the workpiece through the die, a roller conveyor, and a receiving table. Parallel to the main production line, there is an auxiliary one, in which the direction of drawing is the opposite. It is connected to the main transfer conveyors and is located in such a way that the input and output parts of one line are connected respectively to the output and input parts of another.

In this design, the movement of the mandrel occurs in a closed path in the forward (first working stroke) and reverse (second working stroke) directions.

The disadvantages of this design are the presence of lateral movement of the mandrel, and, consequently, the complexity of the design as a whole and a decrease in reliability. During lateral movements, damage to the movable mandrel, which is a long, thin shaft, is possible.

As a prototype, the design of the mill of the Iztm plant for drawing pipes on a movable mandrel was adopted (Z. Pertsikov, Drawn mills, M., Metallurgy, 1986, p. 104 and Fig. 65). The design contains the following main devices: loading table for workpiece pipes, work table, press-in mechanism for a pipe with a mandrel in a fiber, fiber holder with a wire, pipe break-in mechanism, pipe stop mechanism, drawing (pulling) carriage, main drive with traction chains, extraction carriage mandrels, lifting rollers on the inlet side of the mill. Pipe - the workpiece from the loading table is fed to the lifting rollers, which transport it to the pressing mechanism, where its front end is crimped. The mandrel is also set with lifting rollers in the workpiece and with it in the fiber holder. In this case, the thinned part of the mandrel, passing through the break-in mechanism and the pipe stop mechanism, is captured by the drawing cart and drawing is carried out while the pipe is being run-in. Together with the drawing carriage, the mandrel extraction carriage moves and, by the time the drawing is completed, the carriage grips enter the annular groove on the mandrel shank and catch it. The carriage removes the mandrel from the elongated pipe, while the pipe with the rear end abuts against the dies of the pipe stop mechanism. Further, the extraction carriage, moving from the fiber holder, comes to a special copy machine that opens the carriage grips and releases the mandrel. The free mandrel of the lifting rollers is transported to its original position (when the carriage passes, the lifting rollers are lowered) and the cycle repeats.

The disadvantages of the prototype are as follows. To remove the mandrel from the pipe and return it to its original position before charging into the pipe, in addition to the main drive, a lot of drives and mechanisms work: moving the lifting rollers and the mandrel extraction carriage, the carriage grips to catch the mandrel, and the mechanism of interaction between the carriage and the copiers to release the mandrel. Such a complex circuit has reduced reliability, in particular with respect to the capture of the mandrel and its release in the rear position of the carriage. In addition, there is wear of the annular groove of the mandrel in place of its capture. The objectives of the invention are to increase the reliability and simplify the design of the mechanism for feeding and removing the mandrel from the pipe after drawing, as well as expanding the technological capabilities of the drawing mill as a whole.

The problem is solved by creating a mill for drawing pipes on a movable mandrel, including a loading table, a work table, rollers on the inlet side of the mill, a mechanism for press fitting a pipe into a die, a die stand, a rolling mechanism, a pipe stop mechanism, a drawing cart, a main drive with traction chains, located on the desktop, and the mechanism for feeding and removing the mandrel, located on the input side of the mill, with a grip for the mandrel. New in the design is that the mandrel feed and extraction mechanism comprises a drive drum, on which branches of the traction and return drives are laid in opposite directions, the return drive cable being connected to the gripper for the mandrel through the tensioning mechanism, and the traction drive ropes through reversing blocks, rack mounted dies.

A mill for drawing pipes on a movable mandrel is shown schematically in FIG. A diagram of the mechanism for feeding and removing the mandrel is shown in Fig.2, a diagram of the attachment of the ropes to the drive drum is shown in Fig.3.

The mill (Fig. 1) contains a loading table 1, a working table 2 receiving the pulling force, rollers on the inlet side of the mill 3, a mechanism for pressing the pipe into the die 4, a rack for the die 5, a rolling mechanism for the pipe 6, a pipe stop mechanism 7, a drawing cart 8 , the main drive 9 with traction chains 10, the mechanism for feeding and removing the mandrel 11.

Actually, the mandrel supply and extraction mechanism comprises (Fig. 2) a drive drum 12, which is driven through a gearbox 13 from the electric motor 14. A brake 15 is installed between the gearbox and the drum 15. Traction 16 and a return 17 branch of the cable drive are laid on the traction drum 12. The rope of the return drive 17 is connected to the grab 18, which houses the rear end of the movable mandrel 19. The rope of the return drive 17 is connected to the grab 18 through the tensioning mechanism 20, the gripper 18 of the mandrel is equipped with a leveling block 21. The traction rope 16 covers the reversing blocks 22 mounted on the mechanism press fitting of the pipe 4. Since the ropes 16 and 17 together with the drive drum 12 form a closed system, after fixing the ropes at points A and B (Fig. 3), the gap in this system is eliminated by using the tensioning mechanism 20. The rope returns A fixed drive mechanism 23 is mounted near the drive drum 12, which is designed to guide the return cable 17 strictly along the drawing axis. The placement of the ropes on the drive drum 12 (Fig. 3) is as follows: the cable of the return drive 17 is in contact with this drum in T.A, and the cable of the traction drive in T.V, i.e. at points spaced 180 ° apart from each other.

The movable mandrel of the drawing mill contains a middle part on which the plastic deformation of the pipe is carried out, a front thinned part for passing it through the pressing, rolling and gripping mechanisms of the drawing cart, as well as a rear part fixed in the gripper 18 (Fig. 2).

The number of ropes of the traction drive in order to achieve the required allowable force may be more than two. In this case, for each of the traction ropes, a reversing unit is installed at the drawbar, and for each pair of ropes, a surge block is installed on the gripper of the movable mandrel. In the particular case, the number of ropes of the traction drive can be odd, then one of the ropes after passing through the reversing unit with its end is attached directly to the grip of the movable mandrel. Thus, the number of leveling blocks is equal to the whole of dividing the number of ropes of the traction drive by two (i.e., the leveling blocks are installed for all paired ropes of the traction drive).

Along with the use of ropes in the considered drive, flexible ties of known types can be used, for example, chains, flexible tapes, belts or wire.

Let us first consider the process of a single drawing of a pipe with the extraction of the mandrel after the drawing. In this case, the mill operates as follows. In the initial position, the movable mandrel 19 with the help of the rope 17 of the return drive is moved to the extreme rear position relative to the rack 5. When this works, the motor 14, the gearbox 13 and rotates the drive drum 12 counterclockwise. The rope 17 is wound on the drum 12, and the rope of the traction drive 16 is unwound from the drum 12.

The pipe from the loading table 1 moves in the transverse direction relative to the axis of the drawing and is on the axis of the drawing. The rollers on the input side of the mill 3 transport the pipe to the mechanism for pressing the pipe into the die 4. Next, the mechanism for feeding the mandrel 19 to the pipe is turned on. The rotation of the drive drum 12 is clockwise. In this case, the rope 17 is unwound from the drum 12, and the ropes 16 are wound on the drum and the mandrel 19 is fed into the pipe. In this case, the thinned end of the movable mandrel passes through the press-fit mechanism 4, the drawbar 5, the rolling-in mechanism of the pipe 6 and the pipe stop mechanism 7.

After that, the drawing carriage 8 captures the end of the mandrel that emerges from the pipe stop mechanism 7 and, using the traction chains 10 and the main drive 9, makes a working stroke (drawing process). At the same time, a run-in is carried out on the outer surface of the pipe by mechanism 6 for its easy separation from the mandrel. After the rear end of the pipe passes the pipe stop mechanism 7, the drawing process ends. During operation of the main drive, the mandrel feed mechanism simultaneously unwinds the rope 17 and the ropes 16. The mechanism 7 then fixes the rear end of the pipe and, by reversing the feed and extraction mechanism, the mandrel 19 is removed from the pipe and fed to its original (extreme rear) position. The extended pipe is removed from the axis of the drawing, the drawing cart 8 returns to the mechanism 7 and the mill is ready for re-drawing.

The proposed mill can carry out several modes of operation. According to the above-described scheme of work, the process of drawing the pipe on a movable mandrel is carried out with the mandrel being returned to its original position for loading it into the pipe (mode I). We will call regime II such that the mandrel feed mechanism holds the mandrel during the drawing process, and the latter moves somewhat slower than the pipe moves. This allows to reduce the length of the mandrel, and the drawing cart must carry out the capture of the pipe. When operating in mode III, a drawing can be carried out in several passes, without removing the pipe from the mandrel at the intermediate transitions of the drawing. So, for example, according to the scheme of work described above (mode I), the first transition of the drawing is performed using detachable dies. After drawing, the die is opened, and the tube with the mandrel is not removed, but returned back to the position before the drawing began. A smaller die is installed in the rack, and the drawing process is repeated. Thus, the mill of the proposed design also allows you to expand the technological capabilities of the process of drawing pipes on a movable mandrel.

Claims (1)

A mill for drawing pipes on a movable mandrel, comprising a loading table, a work table, rollers on the inlet side of the mill, a mechanism for pressing pipes into a die, a rack for drawing, a mechanism for rolling pipes, a pipe stop mechanism, a drawing carriage, a main drive with traction chains located on the working table, and located on the input side of the mill, the mechanism for feeding and removing the mandrel with a gripper for the mandrel, characterized in that the mechanism for feeding and removing the mandrel contains a drive drum, which is laid in opposite directions there are branches of ropes of the traction drive and the rope of the return drive, the rope of the return drive connected to the gripper for the mandrel through the tensioning mechanism, and the ropes of the traction drive through reversing blocks mounted on the rack.

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