System and method for mold block change on a return track

Abstract

A system and method for replacing or substituting die blocks in a corrugator, the corrugator including a first track and a second track for carrying respective chains of die blocks, each of the tracks including a return track, wherein the system advances a replacement die block to the return track to displace a corresponding die block in the chain of die blocks as the corrugator is producing and as the chain of die blocks is moving.

Description

[0001] Cross-references to earlier applications

[0002] This application claims priority to U.S. Application No. 63 / 202,862, filed on June 28, 2021, under the Paris Convention. Technical Field

[0003] This specification relates to systems and methods for use with a bellows machine for producing bellows. More specifically, this specification relates to systems and methods that allow for the replacement of die blocks in a pipe bellows machine while the bellows machine is running. Background Technology

[0004] Systems used for producing corrugated pipes, also known as corrugating machines, are well known in the art. Typically, such a corrugating machine comprises two sets of die blocks, wherein the pairs of die blocks are positioned together to define a moving die tunnel. This die tunnel is aligned with an extruder, into which molten plastic material is injected through the extruder. The extruded plastic conforms to the shape of the inner surface of the die blocks and advances with the die blocks through the die tunnel. At this stage, the extruded plastic cools, thus forming a pipe.

[0005] These series of mold blocks are set up and carried on endless tracks adapted to rotate in opposite directions. In this way, the mold blocks come together to form a mold tunnel and separate at the end of the tunnel. The tracks return the mold blocks on their opposite sides. In one aspect, these tracks are arranged vertically, with one track above the other.

[0006] Examples of corrugating machines including movable mold blocks are provided in U.S. Patents 9,969,119, 4,504,206, and 4,681,526. The entire contents of these references are incorporated herein by reference as if listed in their entirety.

[0007] Typically, the die blocks used to manufacture bellows have a common internal profile, thereby forming an elongated tube conforming to that profile. However, in some cases, it is necessary to form a section of tube with a different profile. This occurs, for example, when a coupling is formed at one end of the tube to allow connection with an adjacent pipe section. In this case, it should be understood that different die blocks, i.e., die blocks with different internal profiles, must be used to produce the desired shape on the pipe. Therefore, to accommodate this change in pipe profile, the bellows machine must be stopped and the necessary die blocks replaced. With the coupling formed, the bellows machine must be stopped again to allow the replacement die blocks to be replaced with the original ones. It should be understood that this process is very time-consuming, leading to increased downtime of the bellows machine and lost productivity.

[0008] An improved system and method for replacing mold blocks in a bellows machine is needed. Summary of the Invention

[0009] In one aspect, this specification provides a system and method for replacing die blocks in a pipe bellows machine. Specifically, the system and method allow for die block replacement while the bellows machine is producing pipes. In one aspect, as the die block chain moves, a replacement die block is induced into position, and an existing die block on the chain is displaced.

[0010] In one aspect, an apparatus is provided for changing die blocks on a corrugated machine, the corrugated machine having a frame, a first track for carrying a plurality of first die blocks and a second track for carrying a plurality of second die blocks, the first and second tracks being generally parallel to each other, each of the first and second tracks including a corresponding production track and a corresponding return track, wherein the apparatus includes:

[0011] - A pair of first guide rails fixed on a first track, the first guide rails being approximately parallel to the first track and disposed on opposite sides thereof;

[0012] - A pair of second guide rails fixed on the second track, the second guide rails being approximately parallel to the second track and disposed on opposite sides thereof;

[0013] - The first unit, aligned with the first return track and movably supported by the first guide rail;

[0014] - A second unit aligned with the second return track and movably supported by the second guide rail;

[0015] - Each of the first and second units includes a pair of corresponding storage platforms disposed on opposite sides of the respective first and second return tracks, each of the storage platforms being aligned with the respective return track and adapted to support one or more replacement mold blocks;

[0016] - Each of the storage platforms includes a pusher arm adapted to advance the one or more replacement mold blocks and load the one or more replacement mold blocks onto a corresponding return track.

[0017] In another aspect, a method is provided for replacing die blocks disposed on a corrugating machine having a first track for carrying a first die block chain and a second track for carrying a second die block chain, the first die block chain comprising a plurality of first die blocks and the second die block chain comprising a plurality of second die blocks, the first track and the second track being substantially parallel to each other, each of the first track and the second track comprising a corresponding production track and a corresponding return track, wherein the method includes:

[0018] - Store one or more first replacement mold blocks adjacent to the first return track and on a first storage surface aligned with the first return track;

[0019] - Store one or more second replacement mold blocks adjacent to the second return track and on a second storage surface aligned with the second return track;

[0020] -Proceed the first replacement mold block and the second replacement mold block toward the first return track and the second return track, so that the corresponding mold blocks on the first mold block chain and the second mold block chain are shifted;

[0021] -The displacement of the mold block occurs during the movement of the mold block chain.

[0022] In one aspect, the replacement of the mold block and the movement of the mold block chain occur simultaneously. Attached Figure Description

[0023] Features of certain embodiments will become more apparent from the following detailed description with reference to the accompanying drawings, in which:

[0024] Figure 1 This is a side elevation view of a pipe corrugating machine.

[0025] Figure 2 This is a left-side perspective top view of the bellows machine, which includes the system described in this article.

[0026] Figure 3 This is a right-side perspective top view of the bellows machine, which includes the system described in this article.

[0027] Figure 4 This is a left-side perspective bottom view of the corrugated machine, which includes the system described in this article. Detailed Implementation

[0028] As used herein, the term "mold block" will be understood to refer to an object having an internal cavity that defines a profile corresponding to approximately half of the outer surface of the bellows. Therefore, two mold blocks, when aligned, combine to form a mold used to define the outer surface of the tube.

[0029] The term "mold tunnel" will be understood to refer to multiple mold blocks aligned and in which pipes are formed. In the context of the bellows machine described herein, the mold tunnel will be understood as "moving" as the mold blocks advance.

[0030] The terms “comprising,” “including,” “containing,” or “having” are used in this specification. As used herein (including the specification and / or claims), these terms should be interpreted as open-ended terms, indicating the presence of a said feature, integer, step, or component, but not excluding the presence of one or more other features, integers, steps, components, or groups thereof that are obvious to those skilled in the art. Therefore, as used herein, the term “comprising” means “consisting of at least partially…”. When interpreting statements in this specification that include this term, the feature beginning with that term in each statement must be present, but other features may also be present. Related terms such as “comprising” and “containing” should be interpreted in the same manner.

[0031] The phrases “mainly composed of…” or “essentially composed of…” will be understood as general closed terms, but may include additional items, materials, components, steps, or elements that do not substantially affect the essential and novel features or functions of the item with which it is used. For example, it is permissible if trace elements present in a compound but not affecting the properties or characteristics of the compound are present in the language of “mainly composed of…”, even if not explicitly listed in the list of items following such terms. When using open-ended terms such as “comprises” or “includes”, it should be understood that direct support should also be provided for the language of “mainly composed of…” and “composed of…”, as if explicitly stated, and vice versa. Essentially, the use of one of these terms in the specification provides support for all other terms.

[0032] The term "and / or" can mean either "and" or "or".

[0033] Unless otherwise stated herein, the articles “a” and “the” are not intended to limit an element to only one, but should be understood to mean “at least one” or “one or more”.

[0034] Figure 1 A bellows machine known in the art is shown. The bellows machine 10 includes a first track 12 and a second track 14 mounted on a frame 16. In the illustrated aspect, tracks 12 and 14 are mounted on supports 18a and 18b, whereby the first track 12 is arranged perpendicularly above the second track 14, and wherein the longitudinal axes of tracks 12 and 14 are parallel. Tracks 12 and 14 extend between a first end 20 and a second end 22 of the bellows machine. As indicated by arrows 24 and 26 and according to the description, the first track is adapted to rotate clockwise 24, while the second track is adapted to rotate counterclockwise 26.

[0035] As also shown in the figure and further described below, the first track 12 includes a first production track 13, and the second track 14 includes a second production track 15. Production tracks 13 and 15 face each other. In addition, the first track 12 includes a first return track 17 facing away from the second track 14, and similarly, the second track 14 has a return track 10 facing away from the first track 12.

[0036] Each of tracks 12 and 14 carries or supports multiple mold blocks, which move along the track. Figure 1 As shown, a first track 12 carries a plurality of first mold blocks 30, and a second track 14 carries a plurality of second mold blocks 32. Each of the plurality of mold blocks forms a mold block chain, wherein the first mold blocks 30 form a first mold block chain associated with the first track 12, and the second mold blocks 32 form a second mold block chain associated with the second track 14. This specification is not limited to any particular number of mold blocks. As those skilled in the art will understand, the number and size of the mold blocks will vary as needed.

[0037] Mold blocks 30 and 32 are shown herein in schematic form for reference. It will be understood that the system described herein can be used with any known mold block. In particular, this specification is not limited to mold blocks having any particular mold profile.

[0038] Mold blocks 30 and 32 move along their respective tracks in directions 24 and 26, respectively. For example... Figure 1 As shown, when the die blocks 30 and 32 move about the first end 20 of the corrugating machine, i.e., from the respective return tracks 17 and 19 to the respective production tracks 13 and 15, they align to form a die tunnel 34, which includes a die for forming the desired corrugated tube (not shown). At this time, the die blocks 30 and 32 move in a common direction as indicated by arrow 28. The die blocks 30 and 32 remain aligned along the length of the die tunnel 34. As described above, molten plastic from an extruder (not shown) is injected into the die tunnel near the first end 20, and, as those skilled in the art know, the molten plastic exhibits a profile defined by the inner surfaces of the die blocks 30 and 32. In this respect, the inner surfaces of the die blocks 30 and 32 are provided with a profile corresponding to the corrugations to be formed on the outer surface of the tube. As is known in the art, the length of the die tunnel is chosen such that the molten plastic is allowed to solidify, thereby forming the tube.

[0039] As discussed herein and as is known in the art, production tracks 13, 15 are used to align the mold blocks together to form a mold tunnel 34, while return tracks 17, 19 are used to return the mold blocks from the second end 22 of the corrugating machine to its first end 20. As is known in the art, the mold blocks are cooled on the return tracks. In one aspect, when the mold blocks are carried on the respective return tracks 17, 19, adjacent mold blocks may be spaced apart from each other to accelerate the cooling process.

[0040] Typically, mold blocks 30 and 32 share a common mold profile, thereby enabling the formation of a tube of continuous length with a consistent outer profile. Once formed, the tube can be cut to the desired length.

[0041] However, in some examples, the pipe being formed may require a different external profile at a specific cross-section along its length. For example, such a profile may include a coupling formed at the end of the pipe's length, allowing one pipe segment to be connected or coupled to an adjacent pipe segment during pipe laying. This type of coupling is known in the art. As will be understood, when forming such a coupling at the end of a given length of pipe, a different set of module blocks will be required. This specification provides a system and method for replacing one or more different module blocks on a module block chain using module blocks with the desired profile. In a preferred aspect, the system and method allow such module block replacement to be performed while the corrugating machine is still in production. For this purpose, the system and method described herein include a corrugating machine, such as those known in the art, equipped with a waiting station for placing the desired replacement module block and means for advancing the replacement module block to the desired portion of the module block chain before the module block forms a mold tunnel. In this respect, module block replacement is performed when the module block is located on the corresponding first return track 17 and second return track 19.

[0042] like Figures 2 to 4As shown, system 50 is adapted to mate with corresponding first return tracks 17 and 19 of the first track 12 and the second track 14. The system includes two platforms 52 and 54, wherein, as described below, the first platform 52 is adapted to mate with the first return track 17, and the second platform 54 is adapted to mate with the second return track 19. Platforms 52 and 54 are mounted on corresponding guide rails, which are mounted on opposite sides of the corresponding first return track 17 and second return track 19. The guide rails extend generally parallel to the longitudinal axes of the return tracks 17 and 19 and are mounted spaced apart from the opposite sides of the tracks 17 and 19. Specifically, the first platform 52 is mounted on guide rails 56 and 58, which are secured to opposite sides of the frame supporting the first track 12 by support brackets 60 and corresponding support blocks 61. Similarly, the second platform 54 is mounted on guide rails 62 and 64, which are secured to opposite sides of the frame supporting the second track 14 by support brackets 66 and corresponding support blocks 67. Figures 2 to 4 As shown, platforms 52 and 54 are preferably vertically aligned with return tracks 17 and 19, respectively. The purpose of this alignment will be discussed below.

[0043] Although Figures 2 to 4 The brackets 60, 66 and associated support blocks 61, 67 are shown for securing the respective guide rails to rails 12 and 14, but it will be understood that any other securing device may be used for this purpose. This specification is not limited to any particular device used for securing guide rails 56, 58, 62, and 64.

[0044] Stages 52 and 54 are movably mounted on guide rails, thereby adapting each stage to translate along the respective guide rail in a direction parallel to the guide rail. In one aspect, for this purpose, stages 52 and 54 are slidably mounted on the respective guide rails. In this respect, as... Figures 2 to 4 As shown, platforms 52 and 54 are mounted to slide reversibly along guide rails in a direction parallel to the longitudinal axes of return tracks 17 and 19. In one aspect, this slidability is achieved using platforms with grooves for engaging with the respective guide rails. For example, as... Figure 2 As shown, the first unit 52 is provided with grooves 66 and 68, which are adapted to receive guide rails 56 and 58, respectively. Similarly, as Figure 4 As shown, the second stage 54 is provided with grooves 70 and 72, which are adapted to receive guide rails 62 and 64, respectively. It will be understood that other components can be incorporated into the system to facilitate longitudinal movement of stages 52 and 54 along their respective guide rails. For example, the grooves and / or guide rails may be provided with bearings, rollers, wheels, gears, or other such components to allow or facilitate sliding of the stages along the guide rails.

[0045] A stage drive device, such as a travel motor 74, is provided to drive stages 52 and 54 to move along corresponding guide rails. As shown, according to one aspect, the travel motor 74 includes a drive shaft 76 extending from the motor 74 to a bearing 78. The drive shaft 76 is connected in sequence to stages 52 and 54, whereby actuation of the motor 74 causes stages 52 and 54 to translate along their respective guide rails. In one aspect, the drive shaft 76 is connected to stages 52 and 54 via gear and screw mechanisms known in the art. This specification is not limited to any particular means of connecting the motor 74 to stages 52 and 54. The travel motor 74 is reversible, whereby stages 52 and 54 can reciprocate along their respective guide rails. In one aspect, stages 52 and 54 are linked together, in which case the travel motor 74 only needs to be connected to one of the stages, and the movement of said stage is translated into movement of the other stage. As will be understood, this arrangement is preferred for synchronizing the movement of stages 52 and 54. In an alternative, each station can be equipped with a separate motor or other such drive device while achieving the desired synchronous movement of stations 52 and 54.

[0046] Each of the first unit 52 and the second unit 54 is equipped with a corresponding storage platform for storing and receiving mold blocks during the replacement process. For example... Figure 2 and Figure 3 As shown, the first unit 52 has a first storage platform 80 on one side of the return track 17, and a second storage platform 82 on the opposite side of the return track 17. Figure 4 As shown, the second unit 54 has a first storage platform 84 on one side of the return track 19 and a second storage platform 86 on the opposite side of the return track 19. The surfaces of the storage platforms are approximately coplanar with the surfaces of the corresponding return tracks, as will be discussed further below. Each storage platform extends approximately perpendicular to the corresponding return track by a certain distance. As described below, this distance allows the mold block to be held or stored away from the return track before the replacement step.

[0047] Each storage platform is equipped with a corresponding push arm. Thus, as shown, storage platforms 80 and 82 are equipped with corresponding push arms 81 and 83, and storage platforms 84 and 86 are equipped with corresponding push arms 85 and 87. Push arms 81, 83, 85, and 87 are adapted to reciprocate in a direction substantially perpendicular to the longitudinal axes of the first return track 17 and the second return track 19. Preferably, the push arms are driven by a push arm drive device, such as a loading motor 88. In this respect, the loading motor 88 is connected to a drive shaft 89, which in turn is connected to subordinate drive shafts 90 and 92. Subordinate drive shaft 90 is adapted to engage and drive push arms 81 and 83, while subordinate drive shaft 92 is adapted to engage and drive push arms 85 and 87. In this arrangement, the associated push arms are adapted to move in the same lateral direction, such that when push arm 81 moves toward the return track 17, the opposing push arm 83 moves away from the track 17, and vice versa. Similarly, as push arm 85 moves toward the return track 19, the opposing push arm 87 moves away from track 19, and vice versa. As described above, it is preferred that the push arms be driven by a single motor to synchronize their movements. However, it will be understood that the same synchronization can be achieved using more than one motor or drive unit.

[0048] The operation of the main system will now be described. As mentioned above, the corrugated machine comprises a chain of traveling die blocks associated with each of tracks 12 and 14. Figures 2 to 4 In this diagram, the corresponding portions of this chain are shown as a first mold block 30 and a second mold block 32. In these figures, mold blocks 30 and 32 are shown located on their respective return tracks 17 and 19. In one aspect of this specification, one or more replacement mold blocks are provided on the respective storage platforms. For convenience, the one or more replacement mold blocks may be referred to as a “set” in this specification. Figure 2 and Figure 3 As shown, a first set of replacement mold blocks 100 is provided on the storage platform 80, and such replacement mold blocks are held on the platform until the mold block chain advances to the position where the replacement mold block 100 is to be inserted into the mold block chain. As described above, the replacement mold block 100 may include a mold block having a mold profile designed for forming a coupling on a pipe. It will be understood that, although Figure 2 and Figure 3 Two replacement mold blocks 100 are shown, but any number of such replacement mold blocks can be set.

[0049] like Figure 2 and Figure 3As shown, the replacement mold block 100 is placed on the storage platform 80 and located between the return track 17 and the pusher arm 81. When a mold block replacement occurs, the loading motor 88 is actuated, thereby pushing the arm 81 forward in a direction toward the return track 17. This movement causes the replacement mold block 100 to slide against the corresponding mold block 30 on the return track 17. As the pusher arm 81 advances, the replacement mold block 100 displaces the corresponding mold block 30 that forms part of the mold block chain. This movement forces the replaced mold block 30 onto the opposite storage platform 82 on the opposite side of the return track 17, and the replacement mold block 100 is thus added to the mold block chain to participate in the forming of a tube with the desired profile. As will be understood, as the replaced mold blocks 30 are moved onto the storage platform 82, such that they come into contact with the pusher arm 83, the pusher arm 83 moves away from the return track 17 via the loading motor 88.

[0050] like Figure 3 and Figure 4 As shown and as will be understood, a second set of replacement mold blocks 102 is positioned on a storage platform 84 associated with the return track 19, wherein the second set of mold blocks 102 corresponds to the first set of replacement mold blocks 100 for use in the molding process. As described above, the advance of the push arm 85 associated with the platform 84 is synchronized with the advance of the push arm 81. Therefore, the required mold block 32 is replaced by the second set of replacement mold blocks 102, the mold profile and position of which correspond to the first replacement mold block 100 discussed above.

[0051] In a preferred aspect of the system described above, the replacement of corresponding mold blocks 30 and 32 with replacement mold blocks occurs during the operation of the corrugated machine. Therefore, in this case, the mold block replacement occurs as the mold block chains on each of tracks 12 and 14 move. To accommodate this movement, tables 52 and 54 are mounted on corresponding guide rails 56, 58, and 62 and driven by motor 74, as described above. Tables 52 and 54 are initially located near the second end 22 of the corrugated machine. As the position for mold block replacement moves toward tables 52 and 54, motor 74 synchronizes the translation of the tables on the guide rails, causing the tables and their replacement mold blocks to move at the same speed as the mold block chain and in the direction toward the first end 20 of the corrugated machine. The speed of tables 52 and 54 will also be synchronized with the speed of the mold block chain. Thus, there is no relative longitudinal movement (i.e., movement in the direction of the return track) between the replacement mold block and the mold blocks on the mold block chain. Therefore, the push arm can advance, displacing the mold blocks and replacing the mold blocks on the chain in the manner described above. Once the mold block is replaced, motor 74 is actuated again, causing tables 52 and 54 to return to their initial positions near the second end 22 of the corrugating machine.

[0052] It will be understood that when forming couplings, for example, on long pipe sections, the requirement for coupling mold blocks may not be necessary for each rotational cycle of the mold block chain. Therefore, once the replacement mold block 100 has completed the coupling formation and is returning towards stages 52 and 54 on return tracks 17 and 19, the replacement mold block can be removed and replaced by the initial mold blocks 30 and 32, which, when the replacement mold blocks are connected to the mold block chain, are moved to storage platforms 82 and 86 and abut against the corresponding push arms 83 and 87. To achieve this, the loading motor 88 is actuated again, but in the opposite direction. This causes the push arms 83 and 87, positioned on the corresponding storage platforms 82 and 86, to advance towards the corresponding return tracks 17 and 19. Thus, the previously displaced mold blocks 30 and 32 advance into the corresponding mold block chain, thereby displacing the previously connected replacement mold blocks. Therefore, the replacement mold blocks return to the storage platforms and are ready to be incorporated into the mold block chain in subsequent cycles. What will be understood is that this sequence of replacement and reversal of the mold block can be performed any desired number of times to form the desired pipe segment.

[0053] In the above discussion, reference has been made to the use of subject systems and methods for temporarily replacing certain mold blocks to form unique features on a pipe. For example, such a feature could be a coupling. It will be understood that this specification is not limited to any particular mold block construction, and that replacement mold blocks can be used to form any desired feature or profile on a pipe. It will also be understood that this system and method can be used to replace mold blocks with mold blocks having the same profile, as may be necessary, for example, when a mold block is damaged or needs to be replaced.

[0054] In the above description, it has been envisioned that the mold block replacement occurs once per cycle or every two cycles. However, in some cases, it may be necessary to change the tube profile multiple times within a given module cycle. This may occur, for example, when forming a short tube section with a coupling. In this case, the tube length may be less than the length of the mold block tunnel 34. For this purpose, the bellows machine can be equipped with multiple systems as described above. In this case, a first system can be actuated to replace the first set of mold blocks with a first set of replacement mold blocks, and a second system located at a certain distance from the first system can be actuated to replace the second set of mold blocks with a second set of replacement mold blocks.

[0055] The above description refers to a single die block replacement occurring within each die block chain cycle. However, it will be understood that, in other respects, the apparatus and method described herein can be adapted to allow for more than one variation of the tube profile on a section of tube. For example, the tube can be formed with a coupling at one end and its profile can vary further along its length.

[0056] As will be understood from the above description, controllers and the like can be included to coordinate and synchronize the drive mechanisms used for the moving table and the pusher arm.

[0057] While the foregoing description includes references to certain specific embodiments, various modifications to these specific embodiments will be apparent to those skilled in the art. Any examples provided herein are for illustrative purposes only and are not intended to be limiting in any way. Any drawings provided herein are for illustrating various aspects of this specification only and are not intended to be drawn to scale or to limit in any way. The scope of the appended claims should not be limited to the preferred embodiments listed in the foregoing description, but should be given the broadest interpretation consistent with the entire specification.

Claims

1. An apparatus for changing die blocks on a corrugated machine, the corrugated machine having a frame, a first track for carrying a plurality of first die blocks and a second track for carrying a plurality of second die blocks, the first track and the second track being generally parallel to each other, each of the first track and the second track including a corresponding production track and a corresponding return track, wherein, The device includes: - A pair of first guide rails fixed to the first track, the first guide rails being generally parallel to the first track and disposed on opposite sides thereof; - A pair of second guide rails fixed to the second track, the second guide rails being generally parallel to the second track and disposed on opposite sides thereof; - A first unit aligned with the first return track and movably supported by the first guide rail; - A second unit aligned with the second return track and movably supported by the second guide rail; - Each of the first and second units includes a pair of storage platforms disposed on opposite sides of the respective first and second return tracks, each of the storage platforms being aligned with the respective return track and adapted to support one or more replacement mold blocks; Each of the storage platforms includes a pusher arm adapted to advance the one or more replacement mold blocks and load the one or more replacement mold blocks onto a corresponding return track.

2. The apparatus according to claim 1, wherein, The pair of first guide rails extend in a direction parallel to the longitudinal axis of the first rail, and the pair of second guide rails extend in a direction parallel to the longitudinal axis of the second rail.

3. The apparatus according to claim 1 or 2, wherein, The first guide rail and the second guide rail are connected to the frame of the corrugated machine and are at a certain distance from the corresponding first and second rails.

4. The apparatus according to claim 1 or 2 further includes a first drive device for reversibly moving the first unit and the second unit along corresponding first and second guide rails.

5. The apparatus according to claim 4, wherein, The first drive device is adapted to synchronize the movement of the first and second units with the movement of the first and second return tracks.

6. The apparatus according to claim 1 or 2 further includes a second drive mechanism for advancing the push arm.

7. A method for changing die blocks disposed on a corrugated machine, the corrugated machine having a first track for carrying a first die block chain and a second track for carrying a second die block chain, the first die block chain comprising a plurality of first die blocks, the second die block chain comprising a plurality of second die blocks, the first track and the second track being substantially parallel to each other, each of the first track and the second track comprising a corresponding production track and a corresponding return track, wherein... The method includes: - Store one or more first replacement mold blocks adjacent to the first return track and on a first storage surface aligned with the first return track, wherein the first storage surface is movably supported by a pair of first guide rails fixed to opposite sides of the first track and substantially parallel to the first track; - Store one or more second replacement mold blocks adjacent to the second return track and on a second storage surface aligned with the second return track, wherein the second storage surface is movably supported by a pair of second guide rails fixed to opposite sides of the second track and substantially parallel to the second track; -Proceed the first replacement mold block and the second replacement mold block toward the first return track and the second return track, so as to shift the corresponding mold blocks on the first mold block chain and the second mold block chain; -The displacement of the mold block is performed during the movement of the mold block chain.

8. The method according to claim 7, wherein, During the displacement of the mold block, the first storage surface and the second storage surface move synchronously with the first return track and the second return track.

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