JPH0626846B2 - Plastic tube manufacturing method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In the art to which the present invention pertains, it is known to manufacture thermoplastic corrugated tubes or tiles for water supply and drainage devices using a molding apparatus commonly referred to as a corrugator. An exemplary apparatus for this purpose generally consists of a pair of complementary upper and lower assembled molds, each of which is connected along a circulation path having an articulated interconnected circular chain mold block and a forward runway and a return runway. And a device for guiding the mold block. Each mold block is complementary to the mold blocks of the other assembled molds, and the mold blocks cooperate as a set along the forward runway to form a tubular mold axis with corrugated walls. Forming a tunnel extending in the direction. The assembly mold is positioned so that the extrusion head is located at the entrance of the tunnel which is coaxial therewith, and the extruded thermoplastic material is blow-molded to expand and conform to the inner surface of the mold. In such a device, cooling the mold block to facilitate the molding of the thermoplastic tube, as well as inducing a vacuum to ensure their bond between the extruded plastic and the mold tunnel wall. It has also been done conventionally. 1
U.S. Pat. No. 39816 issued Sep. 21, 976
No. 63 describes a corrugating machine having the above characteristics.

Rotating mold blocks inevitably require complex structures and are inconvenient for piping coolant and vacuum, because positive mold cooling is a continuous irreversible or generally spiral path. This is because it is performed only while the mold block along the road is running. Separation of the more troublesome rotary type hose is one of the problems to be solved by this technology.

A complete stoppage of the corrugating device is also required to make the mold changes. That is, in addition to the standard length of corrugated flexible plastic tubes or tiles, there is a need for tube fittings represented by couplings, adapters, end caps, and the like. The production of such fittings requires die changes in the corrugating machine and consequent downtime of the entire die. This fact is 19
U.S. Pat. No. 443,913, published March 27, 1984
It is described near the end of the 0 specification.

Column 9 of the same patent also states that the assembled molds that do not participate in the formation of the mold tunnel are continuously returned along the return path where they are cooled. It is quite clear that installing more assembly molds than would be required for actual production would significantly increase mold cost, and other disadvantages would result therefrom.

The above and other disadvantages of prior art devices are plastic tubes and related parts which are characterized by imparting linear motion to the assembly molds to cause them to reciprocate back and forth in a straight track relative to the molding position. It is effectively eliminated by providing the manufacturing method and the device. The linear movement of the mold block or the assembly mold can take place in various ways, and the actuating device for this purpose can be provided by way of example by means of a fluid or gear device.
An important and novel aspect of the present invention is the installation of one or more stand-by positions, where one or more assembly molds are temporary to receive extrudable thermoplastic material before being returned to the molding position. I can wait for you. This new method of manufacturing corrugated plastic tubes effectively overcomes the known shortcomings of the prior art, and other advantages of Applicants' novel molding apparatus will become apparent from the following description thereof. Ah

FIG. 1 is a side view of a novel apparatus for carrying out the process of the present invention.

FIG. 2 is an end view of the corrugating device taken along line 2-2 of FIG.

FIG. 3 is an end view of the device of the present invention taken along line 3-3 of FIG.

4-16 are schematic diagrams showing a novel reciprocating and waiting device which characterizes Applicant's inventive contribution to the corrugated plastic tube manufacturing technique.

FIG. 17 is a partial side view showing a corrugating device that employs a segment type mold block.

FIG. 18 is a partial cross-sectional view showing one mode of the die interlock device.

FIG. 19 is an end view of an exemplary embodiment of a mold latch device.

Referring first to FIGS. 1, 2 and 3 of these drawings, an exemplary embodiment of an apparatus for manufacturing a corrugated plastic tube and its fittings is generally designated by the symbol A.
It is represented by. The structural skeleton supporting the corrugating device A can take a variety of forms, including a pair of longitudinally spaced end frames 10 and 12 fixed to the substructure, such as 14, and end frames 10 and 12. It may consist of a top frame 16 which is fitted and connected. The structural frame may incorporate additional support members (not shown), or it may be attached to a suitable carriage or similar member if mobility relative to the extruder is required. Each of the vertical members 10a and 12a has an end frame 1
It forms part of 0 and 12.

Roughly speaking, the linear movements of the mold blocks M-1 and M-2 shown in solid lines in FIG. 1 with respect to each other and to the extruder E and the sequential opening and closing of said molds are carried out by a built-in timing function. By means of actuating devices with a large number of interactions responsive to known commercially available control devices with electrical and electronic equipment having The following description relates to the details of the mechanism for performing the novel linear reciprocating and waiting movements of Applicant's corrugating machine A.

Fixed along the upper and lower ends of the end frame 10 and on opposite sides thereof are a plurality of bracket devices 18 supporting the gear box 20. The end frame 10 is provided with a motor device 22 at one end along its lower end, which acts on a drive shaft device 26 via a two-stage reducer 24, which in turn via a gearbox 20. Acts on 28. Support for the speed reducer 24 and its connecting parts is
This is done with the connecting member 30 attached at 32 to the fixed structure.

Extending horizontally between the end frames 10 and 12 is a pair of fixed shaft devices 36 carrying bearing devices 34 through which the bracket device 38 passes through the mold block M-1. And a bearing device (not shown) for opening and closing M-2. Both of the blocks are shown in the closed position in FIG. The pair of upper and lower gear boxes 40 and 42 are mounted by the fixed structure, and the upper and lower drive shaft members 44 extend through the pair of upper and lower gear boxes 48 and 50 (FIG. 3), respectively. And 46. As described above, the motor device 22 acts on the drive shaft device 26 via the two-stage speed reducer 24, and the shaft device 28 is driven by the gear box 20. This shaft device 28 is a gear box 2
0, which in turn causes the upper and lower shaft members 44 and 46, which extend to the upper and lower gear boxes 48 and 50, respectively, by rotating the shaft arrangement 26.

By installing the aforementioned cooperation mechanism, the carriage M-
The mold block on 2 advances at a precisely controlled speed to the active or melt receiving position for extruder nozzle N shown in phantom in FIG. Once the mold M-2 cavity (not shown) has been filled, the following steps are performed using the apparatus described with additional reference to FIG. Assembling the mold block The linear motion of the mold and the opening and closing thereof are first performed by the mold blocks M-1 and M-.
It will be better understood by referring to the support structure for 2.

Appropriately attached to top frame 16 and also end frames 10 and 12
On the opposite side of it is a rod-shaped support and guide member 52, which is in contact with a bearing arrangement 54 and a shaft assembly 56. Additional top shaft support is provided by 58 in FIG. Adjacent to the support structure is precise control of the active position of the mold carriage, ie, the motion of the mold carriage or mold block, represented by M-2 in FIG. 1, to the melt receiving position. Is the first actuation device for. The first actuation device described herein is in the form of a pinion and drive rack device, with the alternative being a precision regulating fluid device,
It will be appreciated that lead screws or chains or the like can be used.

As shown in FIGS. 1 and 3, the linear movements of the mold carriages M-1 and M-2 in the substantially linear path back and forth are caused by a pair of substantially the same first actuators. Done. In short, the basic difference is the mold carriage M-
1 is connected along the top side thereof, whereas in the case of the carriage M-2, the first operation device is supported along the bottom side, that is, the base side. is there. The bracket arrangement 38 for the mold blocks M-1 and M-2 is connected to a drive rack 60 which meshes with a pinion 62 driven by a shaft arrangement 26 terminating in gearboxes 48 and 50, respectively. . The shaft device 26 is a bearing device 64.
Supported by.

To summarize the operation of the first actuator, the motor device 22
Acts on the drive shaft device 26 via the two-stage speed reducer 24, and the shaft device 28 is driven via the gear box 20. The shaft arrangement 28 actuates the gearbox 20, which in turn rotates the upper and lower shaft members 44 and 46 which extend to the upper and lower gearboxes 48 and 50, respectively. The latter gearbox actuates the pinion 62 via the shaft device 26, but because the pinion is in mesh with the drive rack carried by the assembly molds M-1 and M-2, the mold block is the first. The linear movement of the mold takes place in a precisely controlled manner until it reaches the position shown. The cooperative connection between the first actuating device and the second and third actuating devices of the present application will be briefly described below.

The second actuating device is mainly the assembling molds M-1 and M-2.
It is installed to open and close. As best seen in FIG. 2, each of the assembly molds is of the split or clamshell type, thus providing end faces 70a and 70a.
It consists of a pair of semi-cylindrical mold segments having b and 72a and 72b. As can be seen from FIG. 2, when the assembly mold is in the fully closed position immediately before, during or immediately after the injection of the plastic, the end faces 70a and 72 are
a and the end faces 70b and 72b are in contact with each other. An exemplary embodiment of the mold interlock device and an exemplary embodiment of the mold latch device will be mentioned later.

A second actuation device for pivoting the mold segments 70 and 72, shown in solid and dotted lines in FIG. 2, from an open position to a closed position can be provided by a fluid actuated cylinder, preferably a hydraulic cylinder. However, it is generally possible to substitute an equivalent mechanism, and a device such as a gear device, a lead screw, or a chain may be used depending on the situation. Second
The upper and lower hydraulic cylinders 74 and 76 shown in the figure are connected at 78a to a bracket device 78 mounted on a fixed structure, and on their opposite side at 80 via a cylinder rod 82 and a bracket device 84 to a mold segment 70. And welded or otherwise attached to 72. As mentioned above, the mold segment is adapted for pivotal movement in the manner shown in FIG.
It is supported via a bearing device 34 mounted on the 6.

The method of operation of the second actuator will be briefly described with reference to the third actuator referred to below, since the third actuator controls the linear movement of the assembly molds M-1 and M-2. Functions in cooperation with the first actuator. As mentioned above, the second actuator opens and closes the mold segments 70 and 72, while the third actuator, described below, opens the fully assembled mold to the start position in a new and efficient manner. Together with the return, it serves the function of advancing the closed assembly mold, in combination with the first actuating device, in a precise manner in a precise manner to the correct position for receiving the melt from the nozzle N of the extruder E. .

The third actuator of the present invention takes the form of upper and lower fluid actuated cylinders 90 and 92, preferably of pneumatic or hydraulic type. However, as already mentioned in connection with the second actuating device, it is also possible to employ a substitute mechanism in the form of a device such as a gear device, a lead screw or a chain.

As can be seen from FIG. 1, the upper fluid working cylinder 9
Reference numeral 0 denotes a piston device 90a, which is connected to a mold block, that is, an assembly mold M-1 via a bracket device 94. Similarly, the linear motion of the mold block or assembly mold M-2 is achieved by the fluid actuated cylinder 92.
This is performed by the mold engagement bracket device 96 connected to the piston device 92a.

The cooperative operation of the first, second and third actuators is
It will be more fully understood when referring to the schematic diagram of FIG. However, referring to FIG. 1 and particularly FIG. 2 after the mold segments 70 and 72 of the assembly mold M-2 have been opened by the action of the fluid actuated cylinder 76, they are operated by the controller of the corrugator. Assembly mold M-2 with open third actuating device in the form of fluid actuated cylinder 92
To the rear, that is, to the left in FIG. At about the same time
Also, when the fluid actuated cylinder 74 closes the mold segments 70 and 72 of the assembly mold M-1, the first actuator of the type of rack and pinion mechanisms 60 and 62 of the assembly mold M1 takes it to receive the melt. Advance to position. Almost at the same time, the assembly mold represented by reference numeral M-2 in FIG. 1 moves to the left side of the other assembly mold. Closed assembly mold M-2
Is advanced by its first actuating device and is precisely moved by the action of the third actuating device (cylinders 90 and 92) relative to the lower assembly mold. Then the melt injection is started.

Applicant features a new and improved apparatus for back and forth movement of the mold relative to the extrusion position in a linear or essentially straight track, and also the unobstructed waveforms in the linear reversible mold reciprocating motion disclosed herein. It is apparent here that they have provided a novel method and apparatus for manufacturing plastic tubes and related parts. In this way, the above-mentioned disadvantages of the prior art, in particular the drawbacks associated with the previous track arrangements using an irreversible circulating belt in a direction substantially along the spiral track, are hereby effectively eliminated. Of.

The innovative mold running concept described above resulted in a new arrangement of parts and the related process sequence. In this case, one assembly mold stands by in the lower or upper position of the extrusion position. Yes, that is, it is set ready and left for a while. This measure, which differs from the prior art, makes it unnecessary to shut down the corrugating machine in order to make a mold change. As is known in the industry, there is a frequent demand for tube fittings represented by couplings, adapters and the like. Previously, the corrugating machine itself had to change molds to make such parts, which meant downtime for the entire mold.

Shown in phantom in the application drawings is a third assembly mold M-3 for performing the standby function, which function will be described more fully below in connection with the progress of each drawing. . Although not specifically shown, from FIG.
The third assembly mold M-3 comprises the first, second and third actuator devices and other associated structures, so that linear travel is imparted to the device in the manner detailed above. It will be understood.

The novel linear drive and standby combination concept is described below in connection with the schematic diagrams of FIGS. 4-16, but those skilled in the art will recognize the linear predecessor feature itself for some applications. Would be sufficient. However, the combination of the linear movement of the mold and the standby enhances the cost and advantages of the present invention.

In the preceding section, the first actuator provided by the Applicant comprises a drive rack 60 and a pinion 62 with the actuator specifically disclosed in connection with FIGS. 1 and 3, and second The actuator is described as comprising fluid cylinders 74 and 76 under the command of the disclosed actuator. On the other hand, the third actuator is disclosed as encompassing the fluid cylinders 90 and 92 with the disclosed actuator. Within the scope of the schematic diagrams in FIGS. 4 to 16, only some of the components consisting of the first, second and third actuating devices are specifically designated by numbers, so that as the description proceeds Reference will be made to FIGS. 1 and 3 which disclose in detail.

Referring first to FIG. 4 of the schematic diagram, the mold carriages M-1 and M-2 of the corrugating machine A are essentially end-to-end contact and each also has a mold M. -2 is extruder E
In the closed position for receiving the melt from the nozzle N. The mold carriage M-3 installed to manufacture a tube mounting component represented by a coupling, an adapter, a cap, etc. is in a standby position on the lower side. Mold block M-
When the filling of the two caribidites is completed, the first actuating device consisting of the pinion 62 and the drive rack 60 places the assembly molds M-1 and M-2 under the control of the actuating device in the positions shown in FIG. Move forward to.

The control device for the corrugating machine constructed as described above operates the mold block M-2 as shown in FIG. 6 by actuating the second actuating device consisting of the upper and lower fluid actuating cylinders 74 and 76. Open. Mold carriage M-1 and M-
3 still remains in the rest position at this point, again as shown in FIG. The control device thereto activates a third actuating device consisting of fluid actuated cylinders 90 and 92, causing the open mold block M-2 to retract past the mold block M-1 to the position of FIG. Reach

Then a pneumatic or hydraulic cylinder 7 consisting of a second actuator
4 and 76 close the mold block M-2 under the action of the controller of the corrugator. A third actuating device, including fluid actuated cylinders 90 and 92 or equivalent device, advances closed mold block M-2 until it abuts mold block M-1 as shown in FIG. . This action causes the drive rack 60 to move the pinion 6 of the gearboxes 48 and 58.
2 (first actuating device), the movement of the working die M-1, that is, the movement to a precise position for accurately receiving the melt from the pressing machine E is controlled.

Referring to FIG. 9, the mold block M-1 is shown open, which is done by the second actuation device after the end of the molding process. The mold blocks M-2 and M-3 shown in FIG. 9 are in the same positions as in FIG.

In FIG. 10, the mold blocks M-1 and M in the open position are under the control of a separate third actuating device consisting of upper and lower fluid actuated cylinders 90 and 92 or generally an equivalent device.
It can be seen that -3 is moved rearward past the closed mold block M-2 to reach the standby position at the rear.
From a comparison of Figures 8 and 10, it is clear that the standby position can be either in front of or behind the working mold.

Applicant's novel sequence of straight running and waiting steps in the manufacture of corrugated tubes is further clarified by FIG. In the figure, the mold block M-3 is closed by the second actuating device, and further moved forward by the action of the third actuating device to contact the mold block M-2. At this point, the first actuator, in the form of a pinion 62 and drive rack 60, functions as described above to control the precise position of the working mold (M-2) relative to the extruder nozzle.

In FIG. 12, the mold block M-1 remains in the stopped standby position, the mold block M-2 is opened by the second actuator, and the mold block M-3 is slightly advanced by the third actuator. ing. In FIG. 13, the mold block M-
1 is waiting in the rear device and the open mold block M-2 is retracted past the working mold M-3 under the action of the third actuator.

In FIG. 14, mold block M-2 is closed by a second actuating device consisting of fluid actuated cylinders 74 and 76 or equivalent devices, while mold blocks M-1 and M-2 are generally shown in FIG. It can be seen that it stays in the same position as in. However, as shown in FIG. 15, the novel process sequence is continued by the mold block M-2 which is advanced to the working position by the action of the third actuator.
The mold block M-3 is opened by the second actuator.
Although the process sequence can be regarded as completed by the open mold block M-1 moving forward from the rear standby position,
As shown in FIG. 16, the mold block M-3
Is moved to the rear standby position by the third actuator.
The mold block M-2 remains in the working position, but the process cycle is related to the previously described FIG. 4 mold block M-1.
It will be repeated by closing.

Mold structure consisting of a number of separable openable segments arranged in end-to-end abutting relationship when each pair of mold blocks is closed to receive an extrudable thermoplastic material. It is also within the scope of the invention to provide
The segmented mold placement, envisioned as described above, allows the use of reduced length extruder heads, facilitates melt feed from the side-directed extruder, and further mold segment sequential The provision of the opening improves the support of the extruded tube shape. The opening and closing of the mold segments can be done not only sequentially, but simultaneously in the mold carriage.

An exemplary device having these and other advantages is shown in FIG. 17, which is described below. The corrugating device illustrated therein is generally designated by the letter C and includes a structural frame 100, which device is essentially the one described in connection with FIGS. 1-3. Can have the same configuration. The corrugating machine operating mechanism and the control device, the drive device, and the above-mentioned first, second and third operating devices are not specifically shown in the same figure, but of course they are incorporated in the device C of FIG. ing.

The corrugated plastic tube manufacturing device C is engaged with a stationary extruder E-1 equipped with a nozzle device N-1. Skeleton 100 through the use of a third actuation device or its equivalent
The mold carriage device 10 can move back and forth along the carriage.
2 and 104, which support a plurality of second actuators 110 via shaft devices 106 and 108, the second actuators being provided by fluid actuated cylinders or equivalent devices. Separately or separably coupled to each of the second actuators 110, or in any suitable manner, are an equal number of pairs of mold segments 112, six of which are shown. Can be changed significantly.

How the device C operates will be apparent from the above description given in connection with FIG. Mold segment 112
Is driven back and forth by means of a third actuation device in connection with FIGS. 1, 2 and 3 and the accompanying description. Similarly, opening and closing of the desired mold segment 112 is accomplished through the use of the second actuator, which is disclosed in detail in the previous section. The first actuator provided by the pinion and drive rack controls the mold movement from the inventive concept portion of FIG.

It is sometimes desirable to provide an interlock between the end-to-end die blocks or segments thereof, especially when one of the die blocks is in the actuated or melt receiving position and the opposing die blocks are in contact. This is the case when the mold block or the good one is in the standby position. This was previously described in connection with the mold blocks M-1 and M-2 of FIG. 1, but it is particularly relevant to the working mold M into the correct position for receiving the melt from the extruder nozzle N. -2 relating to the action of the pinion 62 and the drive rack 60 which constitutes the first actuation device for controlling the precise movement of the -2. One of the advantages of the die interlock mechanism is that it prevents melt leakage between the opposing die blocks and that the extruded material is blown against the die cavity contour by vacuum forces. The prevention of air leakage.

Although an exemplary mold interlock mechanism is shown in FIG. 18 in connection with a segmented mold structure, this concept is also apparent in the mold block of the structure shown in FIGS. 1 and 3. Is applicable to. Each mold segment 210 in FIG. 18 may be machined complementarily, or may have a protruding, or claw, to provide a mating interlocking engagement with the recessed or grooved surface 210b of the next adjacent mold segment 210. Machining along its perimeter is provided to provide tongue 210a. In this way, the possibility of melt or air leakage is essentially completely prevented.

In the clamshell form of mold construction having the features shown in FIG. 3, a halving mold is illustrated by a second actuation device illustrated by fluid actuated cylinders 74 and 76 or using an equivalent device as described above. It may sometimes be desirable to more closely secure the molds to each other after closing.
The present invention provides a locking or latching device for providing a tighter lock of a split mold, which is the first.
It is shown in FIG.

As shown in the figure, the mold halves 300 and 302 have bracket devices 304 and 306 supported by a shaft device 308 at one end thereof. The split mold 300 at the other end is provided with a catch device 310 that engages with a pawl or finger device 312, which is pivotally attached by a pin device 314 to a bifurcated bracket device 316 supported by a split mold 302. Has been done. The pin device 314 and the bracket device 316 also support a lever arm 318 that is pin coupled or otherwise attached at 320 to the coupling device 322,
The coupling device is further provided at 324 with a split mold 302.
It is fixed to. The illustrated and described latching device is able to ensure a tight fit of both mold halves in a sealed relationship.

While various changes and modifications to the present invention have been described,
These and other changes can, of course, be implemented without departing from the spirit of the invention or the scope of the appended claims.

[Brief description of drawings]

FIG. 1 is a side view of a novel apparatus for carrying out the process of the present invention. FIG. 2 is an end view of the corrugating device taken along line 2-2 of FIG. FIG. 3 is an end view of the device of the present invention taken along line 3-3 of FIG. 4-16 are schematic diagrams showing a novel reciprocating and waiting device which characterizes Applicant's inventive contribution to the corrugated plastic tube manufacturing technique. FIG. 17 is a partial side view showing a corrugating device that employs a segment type mold block. FIG. 18 is a partial cross-sectional view showing one mode of the die interlock device. FIG. 19 is an end view of an exemplary embodiment of a mold latch device. A, C ... corrugating device, E ... extruder, M-1, M-
2, M-3 ... Mold block, N ... Nozzle, 10, 1
2 ... End frame, 10a, 12a ... Vertical member, 16 ... Top frame, 26 ... Shaft device, 34 ... Bearing device, 36 ... Shaft member, 38 ... Bracket device,
48 ... Gear box, 52 ... Supporting and guiding member, 60 ...
... Drive rack, 62 ... Pinion, 70, 72 ... Mold segment, 70a, 70b, 72a, 72b ... End surface, 74, 76 ... Hydraulic cylinder, 90, 92 ... Cylinder, 100 ... Skeleton, 102 , 104 ... Mold carriage device, 106, 108 ... Shaft device, 110 ...
… Second actuating device, 210 …… Mold segment, 210a
...... Tongue surface, 210b ...... Groove surface, 300, 302 ......
Split mold, 310 ... Catch device, 312 ... Finger device, 318 ... Lever arm, 322 ... Coupling device

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B29C 69/02 7344-4F B29L 23:18 4F

Claims (12)

[Claims] 1. A molten plastic material is supplied to a mold cavity, the material is molded in the cavity according to its contour to manufacture a plastic tube having a predetermined length, and the cavity is formed into the plastic tube. Moving from a length, advancing the cavity to a lower position along a straight track, retracting the cavity from the lower position to a straight upper position along the straight track, and further moving the mold cavity. A method of making a plastic tube comprising advancing from a good position along a straight path and intimately contacting a second mold cavity into which molten plastic material is being supplied prior to supplying the mold cavity. 2. Arranging the first and second closed mold cavities in a substantially tangential relationship, feeding molten plastic material to the second closed mold cavity and molding plastic parts therein. , Opening the second closed mold cavity and advancing it along the straight track to a lower position while simultaneously moving the first closed mold cavity along the straight track to supply molten plastic material therein. Advancing, moving the open mold cavity from the lower position to the rear along a straight path to its upper position in close contact with the first closed mold cavity, further closing the open mold cavity and closing it. A method of manufacturing a plastic part, comprising positioning relative to a subsequent supply of molten plastic material. 3. Placing a third mold cavity open in spaced apart, preliminary positions below the first and second mold cavities, and if necessary, the third mold cavity. 3. The method of claim 2 comprising displacing the molten plastic material therein along a straight path from the preliminary position to a straight rearward facing direction of the first and second mold cavities. Plastic parts manufacturing method. 4. A plurality of mold cavities are sequentially moved forward and backward with respect to a source of molten plastic material that can be extruded in a linear direction along a straight path, one of said cavities being a molten plastic material therein. During the feeding of the mold, opening one of the mold cavities after molding the plastic parts therein, moving the open cavity downward along a straight path, another one of the mold cavities. Closing for feeding molten plastic material therein, moving said lower open mold cavity rearward along a straight track and laying well past said another closed mold cavity. , Closing said one mold cavity, and said one of said one for further movement of the molten plastic material into the receiving position. Plastic component manufacturing method comprising the Kusarikin cavity since it is another closed mold cavity substantially Taise' said. 5. A method of manufacturing a corrugated plastic tube, wherein a plurality of mold cavities are reciprocated to and from a plastic material source that can be extruded along a straight path, said mold cavities being moved therein. Sequential opening and closing after and before the supply of plastic material, and also an open mold cavity for receiving the molten plastic material later during the reciprocating movement along a straight track, past the mold cavity closed backwards. An improvement consisting of moving to a position just above the sea level. 6. A support frame, a plurality of mold carriages mounted by the frame for linear traveling along the frame, a pair of mold blocks connected to each of the carriages, and one of the carriages. A first actuation device for moving the die block above it to an extrusion position for feeding the molten plastic material along a straight path, and a second actuation for opening and closing the die block before and after feeding the plastic material into it. A device, a third actuating device for moving another one of said carriages and an open mold block on it rearward along a straight path past a pair of closed mold blocks, said first, second And a plastic tube manufacturing apparatus comprising a starting device for controlling a third actuating device. 7. In order to precisely control the position of the mold carriage and the mold blocks above them with respect to the extrusion position,
7. A device having the characteristics of claim 6, wherein a device connecting the first actuating device and the third actuating device is installed. 8. The apparatus of claim 6 wherein said first actuator comprises a pinion and drive rack mechanism and said second and third actuators are fluid actuated cylinders. 9. A support frame, an extruder engaged with the frame for discharging molten plastic, and an attachment device coupled to the frame for reversible linear travel along it, operating independently. A device coupled to the mounting device, the device comprising a plurality of mold cavities hinged together,
The mounting device and the mold, each of which sequentially opens and closes the mold cavity, and which moves the mounting device and the mold cavity connected thereto to the front and the rear along a straight path with respect to the extruder. A corrugated plastic tube manufacturing apparatus comprising a plurality of actuators connected to a cavity and an activator for controlling the actuators. 10. The feature of claim 6 wherein each pair of mold blocks is complementarily formed with a mating surface on its perimeter to provide a substantial interlocking engagement therebetween. apparatus. 11. An apparatus having the features of claim 6 wherein each pair of mold blocks comprises a plurality of separable and independently controllable mold segments arranged in side-by-side relationship. 12. A latching device having a clamshell structure in which each pair of mold blocks is hinged at one end thereof and at the other end for tightly securing the clamshell mold blocks. 7. An apparatus having the features of claim 6 wherein: