FI62245B - REFERENCE TO A RESOLUTION FOR A PARTICULAR PURPOSE OF A PLASTIC MACHINE - Google Patents

Description

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Ma 1 j '' utlAggningsskrift 6zz4 5 c <45> Fa ten 1.:,1 oyilnnctty 10 12 1932 Patent jineddelat (51) Kv.ik.Vo. B 29 c 17/02, B 29 D 23/00 FINLAND —FINLAND (21) IWttlK »k.rm * -P« t.flt »» »6ki» * nf T82560 (2, 22.08.78 V '(23) AlkupiM — Glltlghatfdtg 22.08.78 (41) Tullut JulklMkil - UMt offwttfif 23.02.80

National Board of Patents and Registration .... ........ ._. t ...., „. .

__ „. ___, (44) Date of export and date of export. - 31.08.82

Patent · och registerstyrelaen Amttkan ekfd och utUkrtiM pubUcmd (32) (33) (31) hnMsttjr «Tuotkou» —Äcjird priorkct (Tl) Asko-Upo Oy, PO Box 99 »15100 Lahti 10, Finland-Finland (FI) (72) Ilkka The present invention relates to a method for obtaining the desired wall thickness of a plastic pipe sleeve part. to obtain using a tamping in connection with a sleeve, according to which the sleeve end of the tube is first brought to a heating station for softening, then the sleeve end is moved to a tamping station to increase the wall thickness of the point to be sleeve and finally the sleeve end is moved to a sleeve station for actual sleeve.

The invention also relates to an apparatus for carrying out this method.

In the manufacture of sleeves used at the ends of plastic pipes, i.e. the so-called the sleeve expands the diameter of the pipe end, which at the same time results in a thinning of the wall thickness. The thinning is strongest at the sealing groove, where the diameter becomes greatest. However, the pressure pipe standards of most countries do not allow the wall thinning described in the sleeve described above, because the operating stress could then rise too high. The wall thickness 2 62245 must therefore be proportional to the diameter of the respective sleeve, which can be achieved by the following methods:

A reinforcement sleeve is placed on top of the sleeve part of the pipe before the sleeve. However, due to the manufacturing costs of the sheath sleeves and the costs of their storage and transportation, the method is relatively expensive. In addition, the use of slender makes it difficult to automate the molding.

The wall of the pipe is thickened in connection with the pipe manufacturing process at the point where the sleeve is formed. However, placing the thickener in the right place on the pipe is problematic and uncertain. In a fast production process, both mechanical and process technical difficulties arise in the operation of the extruder and the drawing device. It should also be noted that in the event of a failure in the thickened part of the sleeve, the pipe must be scrapped.

The wall of the pipe is reinforced in connection with the formation of the sleeve. In this case, the heated end of the pipe is placed on a shaping mandrel which gives the final shape, after which an axial pushing movement is made on the end of the pipe. Around the molding mandrel is a mold, the space between the inner surface and the mandrel of which is filled during filling. There are two different basic applications of the method. One of them has a molding mandrel and the mold is cooled. In another embodiment, the mandrel and mold are heated to or above the plastic deformation temperature during annealing, after which the heating is stopped and cooling is turned on.

However, when a cooled molding mandrel and mold is used, the tube cools rapidly as it enters the mandrel and its ductility decreases. Therefore, large pushing forces are required, leading to expensive equipment. In addition, there are high internal stresses in the finished sleeves, which weaken the strength of the sleeve. When using an alternately heated and alternately cooled mandrel and mold, the cycle times become long and production slows down. Manufacturing automation is also becoming more difficult.

SE patent publication 399 008 discloses a method according to which the heating, tamping and molding take place in principle on the same workstation. The pipe to be treated and the necessary equipment are moved axially relative to each other in different work stages. In addition, the inside diameter of the tube remains unchanged after annealing.

3 62245 The disadvantage of this method is the relatively long processing time, since each work step must be performed before the next step can be started. In addition, the expansion of the pipe cannot be performed during the filling, but only during the molding. In this case, the end of the pipe, which already has a thickened wall thickness, has to be pushed onto the molding mandrel, which requires a large thrust and makes the molding more difficult.

DE-A-1 257 413, on the other hand, discloses a method in which a heated tube is inserted into a cavity formed by a mold mandrel and an outer mold, whereby the tamping and the molding take place simultaneously.

In this method, the temperature of the mandrel and mold must be relatively high during the tube insertion and filling phase, after which it must be sharply lowered to cool the tube. Changing the temperature requires complex hardware and also makes the processing time long.

It is an object of the present invention to obviate the disadvantages of the methods described above and to provide a new type and more efficient method and apparatus for punching and molding.

The solution according to the invention is characterized in that the transfer of the pipe-forming end from the heating station via the filling station to the forming position is performed by moving the pipe laterally parallel to the previous position and that

In the solution according to the invention, the heating, the tamping and the sleeve are thus clearly separated from each other and each is placed in a separate workstation on the machine. The workstations are equally far apart. Intermittent transfer equipment moves the pipe from one station to another. Thus, in the period between transfers, one work step takes place simultaneously at each workstation.

Compared to the solutions presented above, this means at least the following advantages: - Significantly more finished pipes can be produced in a unit of time.

- During punching, it is easy to expand the sleeve and thus make it easier to push the pipe onto the mandrel during molding.

4,6245

The apparatus according to the invention comprises a transfer device for moving the pipe from one working step to another and workstations for heating, pushing and shaping the muffled end of the pipe, characterized by a transfer device simultaneously to the transfer device so that each tube is at one workstation.

Due to the above, the method is perfectly applicable to automatic production.

It should also be noted that if the sleeve fails, the pipe does not need to be scrapped, but the defective sleeve can be cut off and the remaining pipe re-sleeved.

The invention will now be examined in more detail by means of an exemplary embodiment according to the accompanying drawings.

Figure 1 shows a perspective view of one forming machine according to the invention.

Figure 2 shows the machine seen from the direction I of Figure 1.

Figures 3-6 show in cross-section a tamping device according to the invention at different stages of tamping.

Figure 3 shows the device in the initial position before tamping.

In Figure 4, the sleeve tube is placed on the mandrel of the stuffing device.

In Fig. 5, the tube is locked in a tamping device, after which the end of the tube is tamped by means of a tamping ring, whereby the shaping space between the mandrel and the mold around it is filled.

In Fig. 6, the end of the tube is removed from the tamping device while using the tamping ring as an ejector.

The forming machine shown in Figures 1 and 2 has four different workstations numbered 1-4. The transfer of the pipe from one workstation to another takes place by means of a turret-type transfer device 5, the circumference of which has fastening devices 6 for fastening the tube to the transfer device during the transfers and the various work steps. The detailed structure of the fastening devices 6 is not essential to the invention and is therefore not shown in detail in Figures 1 and 2. The fastening device 6 may be a pair of jaws for gripping the pipe, one jaw being fixed and the other movable

5 6224S

or whose both jaws are movable. The opening and closing of the jaws can take place, for example, by means of compressed air cylinders attached to the transfer device 5.

The pipe 7 to be clamped is placed in the transfer device 5 at the workstation 1, where the length adjustment of the pipe end is further performed by the setting device 8. After the length setting, the tube is fixed to the transfer device 5 by means of fastening devices 6.

The pipe is then moved by turning the transfer device 90 ° to the workstation 2, where the heating of the pipe end is carried out by means of a heater 9.

After heating, the pipe is transferred to the workstation 3 / where the end of the pipe is pushed by means of the stuffing device 10 as described below.

After stamping, the pipe is transferred to the workstation 4, where the molding is performed by means of the molding tool 11.

The heater 9 and the shaping tool 11 are known per se. They, as well as the tamping device 10, are attached to chips or the like by means of which they are moved in the longitudinal direction of the machine to get the devices to and from the end of the pipe at the beginning and end of each work step.

After the molding, the jaws of the fastening devices 6 in the workstation 4 are opened, and the pipe is dropped out of the molding machine.

The tamping device 10 in the workstation 3 is a separate unit, such as a heater 9 and a molding tool 11. It is fixed by its body 12 to a frame 13 on a slide or the like in the machine (the tamping device mandrel 14 is fixed to the body 12 .

Around the mandrel 14 is a mold 15, which is also fixed to the body 12. Between the mandrel 14 and the mold 15 there is a bellows ring 16, at the other end of which a mandrel 18 is attached.

At the front end of the stuffing device there is a ring 20 which is guided into the device by means of pins 37 and which can be moved by means of cylinders 21 in the direction of the longitudinal axis of the device (only one of pins 37 and cylinders 21 is shown in the figures). Inside the ring there are four jaws 22 (two shown in the figures) which guide the ring 622245 by means of guides 23 and 24. The jaws are further loaded by springs 25 via pins 26 in the direction of the longitudinal axis of the device and keep the end faces 27 and 28 of the jaws and the mold in contact with each other. With the guides 23 and 24 at a certain angle to the longitudinal axis of the device, the jaws 22 can be displaced by moving the ring 20 in the direction of the longitudinal axis. As the ring 20 moves to the right (Figures 3 and 6), the jaws 22 move radially outward from the center of the device. As the ring 20 moves to the left (Figures 4 and 5), the jaws 22 move toward the center of the device.

The tip of the mandrel 14 has a ring 29 made of, for example, spring steel and cut at one point around its circumference so that the ring can be expanded somewhat radially. The expansion is performed by moving the mandrel 18 to the right, whereby the small conical surface 30 on the mandrel pushes the pieces 31 (only one piece shown in the figures) radially outwards, which in turn forces the ring to expand. The ring remains expanded as long as the pieces 31 rest against the straight portion 32 of the mandrel 18 (Figure 5).

Both the mandrel 14 and the mold 15 are heated by electric resistors or a heating medium introduced into the cavities 35 and 36.

After the transfer device 5 has moved from the pipe machine workstation 2 to the workstation 3, the stuffing device 10 moves in the longitudinal direction of the machine by means of a slider or the like in the machine (Fig. 3). The movement continues until the mandrel 14 has penetrated the heated tube 33 to a predetermined length. The ring 20 is then moved to the left by means of the cylinders 21, whereby the jaws 22 move towards the center of the device, squeezing around the tube 33 (Fig. 4).

The next step is the actual pulsation, which takes place by means of the punching ring 16 (Fig. 5). As the cylinder 19 begins to push the thrust ring 16, the mandrel 18 also moves forward and the conical surface 30 pushes the pieces 31 out of the center, causing the ring 29 to expand radially and the tube 33 to lock between the ring 29 and the jaws 22. This prevents axial displacement of the pipe due to the pushing forces. As the pushing movement continues, the pieces 31 rest against the straight part 32 of the mandrel 18, keeping the ring 29 expanded and thus also locking the tube 33. During the pulsating movement, the shaping space 34 between the mandrel 14 and the mold 15 is filled. The heated mandrel 14 and mold 15 retain the plastic end of the tube for the post-tamping molding operation.

At the end of the pushing step, the ring 20 is moved to the right by means of cylinders 21, whereby the jaws 22 move outwards from the center of the device, releasing the locking of the tube 33 (Fig. 6). Thereafter, the pushing ring 16 begins to eject the end of the tube, and simultaneously with the ejection movement, the entire pushing device 10 moves backwards by means of a slider or the like on the machine (Fig. 6). During the ejection, the spindle 18 also moves forward, whereby the pieces 31 come into contact with the lightened part 38 of the spindle, allowing the ring 29 to contract so as not to impede the ejection (Fig. 6).

After the pushing device 10 has moved back so far that the end of the tube 33 has been completely released from it, the transfer device 5 moves the tube to the work station 4 for molding. In the tamping device, the tamping ring 16 and the spindle 18 are pulled to the rear position shown in Fig. 3 ready for the next tamping step.

The forming machine shown in Figures 1 and 2 has four different workstations. The number of workstations can also be different from four. Thus, for example, in order to increase the efficiency of heating, one more heating station can be installed in the machine, whereby the number of workstations increases to five.

Claims (3)

8 6 2 2 4 ^ Claims: w A method for obtaining a desired wall thickness of a sleeve portion of a plastic pipe (T) using tamping in connection with a sleeve, which method first places the sleeve end of the tube (7) in a heating station (2) for softening, then moves the sleeve end by pushing and finally the sleeve end is moved to its sleeve (i) for the actual sleeve, characterized in that the transfer of the sleeve end of the pipe (7) from the heating station (2) via the sleeve station (3) to the sleeve parallel to the position and that while the tube (7) moves from one position to another, the next tube to be formed moves to the previous position, so that in each workstation (2, 3, k) one work step takes place simultaneously with the other work steps. A method according to claim 1, characterized in that said transfer is performed by means of a rotational movement. Apparatus for carrying out the method according to claim 1 for obtaining the desired wall thickness of the sleeve part of a plastic pipe (7) by means of a tapping sleeve, the apparatus comprising a transfer device (5, 6) for transferring the tube (7) from one stage to another characterized in that the transfer device is a stepping transfer device (5) of the revolver type, which moves the tube (7) from one working step to another laterally parallel to the early position and has a plurality of fastening devices (6) on the periphery ) so that each tube is at one workstation (2-U).