The subject matter of the present invention relates to a method of molding spokes of a non-pneumatic tire by utilizing an array of molds that can cycle through a platen press. More particularly, the present application involves a method of manufacturing spokes in which the molds are sequentially moved through a platen press during curing with following molds taking their place in sequence.
Non-pneumatic tires are those that do not require air or other fluid for their inflation for use. Some non-pneumatic tires have a plurality of spokes arranged circumferentially around and attached to a hub. On their opposite end, the spokes are attached to a shear band. To build the spoke component of the non-pneumatic tire, it is known to combine various products into a multi-component product and then cure this product in a mold. One type of mold used in the production of spokes is a mold that features segments that engage the spoke on the top, bottom, left and right hand sides. The segments of the mold are fastened, bolted, screwed, or otherwise secured into one another to form a closed compartment that engages the spoke and applies pressure thereon. Spokes of a particular size/configuration that require the same time for curing are placed into individual molds and force and heat are applied until the right amount of curing is achieved. The molds are then opened, the spokes removed, and the molds are refilled with new green spokes for subsequent curing. The process of loading the molds, demolding, and placing the molds into a press is done manually and is highly labor intensive. The process of molding a product may involve a press having the top and bottom portions shaped to receive and form the product to be molded, and this top and bottom are attached to the press and are not removable therefrom, instead the products are themselves put into and pulled out of these press molds.
The construction of multi-sized non-pneumatic tires requires the construction of spokes that are of different sizes, strengths, and configurations. Although it is known to use fixed molds to mold products, and to use a press to mold a single product, there remains a need to mold spokes having different cure time requirements in an efficient manner. As such, there remains room for variation and improvement within the art.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
The use of identical or similar reference numerals in different figures denotes identical or similar features.
Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a third embodiment. It is intended that the present invention include these and other modifications and variations.
The present invention provides for a method for molding spokes 10 of a non-pneumatic tire 66. The method utilizes a platen press 12 into which various molds 70 in an array that carry green spokes 20 are positioned. Some of the molds 70 are arranged to mold spokes 10 that have different cure times. This may be because the size and/or composition of the spokes 10 are not the same. Spokes 10 having different cure times are simultaneously present within the platen 12 and heat and force is applied to the molds 70 to cure the spokes 10. The platen 12 can be opened to remove its force from the molds 70, and additional molds 70 with spokes 10 can be loaded into the platen 12 and those spokes 10 that have been cured a sufficient amount may be removed from within the platen 12. The molds 70 may be arranged in an array in a series of rows 32, 34, 36, 38, 40, 42 within the platen 12 so that they are organized via their particular required cure time. The new molds 70 entering the platen 12 are positioned into the rows 32, 34, 36, 38, 40, 42 corresponding to their particular required cure time and in so doing molds 70 on the other end of the rows 32, 34, 36, 38, 40, 42 that have been in the platen 12 for their required amount of time are pushed out. The method thus allows for molding spokes 10 that have different cure times within the same platen 12 at the same time. The spokes 10 with the different cure times may have the platen 12 apply the same amount of force to all of them when in the platen 12 during the curing.
The spoke 10 is shown in perspective view in
In use of the mold 70, the green spoke 10 is placed onto one of the first or second engagement surfaces and the top and bottom pieces 24, 26 are moved towards one another into the closed position. The spoke 10 engages both of the engagement surfaces and will have pressure and heat applied for an amount and time sufficient to cure the green spoke 20 and produce a cured spoke 22. The mold 70 can then be opened so that the top and bottom pieces 24, 26 are moved away from one another. The spoke 10 may be demolded from the top or bottom piece 24, 26 and the pieces 24, 26 can be prepared to receive a new green spoke 20 for subsequent molding. The pressure applied to the mold 70 may come from a platen 12 that presses onto the mold 70 to in turn apply force to the spoke 10 within the mold 70. Heat can be transferred from the platen 12 or some other source into the spoke 10 to effect curing of the spoke 10.
A perspective view of a section of a platen 12 that can be used for applying force to molds 70 is illustrated with reference to
The platen 12 has a base onto which the molds 70 are positioned. A top section of the platen 12 is movable relative to this base in the vertical direction. The top can be moved via one or more hydraulic cylinders in order to move down onto the molds 70 and squeeze the molds 70 between it and the base. Heating elements can be present in the base or in the top movable portion, or both, so that heat may be transferred into the molds 70 and into the green spokes 20 within the molds 70. The platen 12 may be defined as the portion of the system in which molds 70 are positioned and force is applied to them by the top section and in which they are heated. The platen 12 may or may not include the robot 30, the transports 76 and 78, and the mold open and close areas 62, 64 in some embodiments.
The molds (x) are arranged within the platen 12 so that molding/curing can take place utilizing molds (x) with green spokes 20 having different cure times. In this manner, molds (x) with different cure times can be cured with one another in the same platen 12 at the same time. The molds (x) with less cure time will spend less time within the platen 12 than those molds (x) requiring more cure time. The molds (x) are arranged in an array in a series of rows within the platen 12 so that their time sequence in the platen 12 can be easier realized. As used herein, the term “array” refers to the organizational structure of the mold 70 pattern within the platen 12. The molds -(1) are identified as a first series 14. The molds -(1) of the first series 14 are positioned in a first row 32 and a second row 34. In other arrangements, only a single row 32, 34 can be present, and in yet other arrangements more than just the two rows 32, 34 of the first series 14 are present. Also, although immediately adjacent one another, the two rows 32, 34 of the first series 14 may be separated by rows of other series in other embodiments. The molds -(1) of the first series 14 are grouped into the first series 14 because they all carry green spokes 20 that require the same amount of cure time within the platen 12.
A second series 16 is also included within the platen 12 and includes molds -(2) that each have green spokes 20 that require the same amount of cure time within the platen 12. The green spokes 20 of the second series 16 in the molds -(2) require an amount of time within the platen 12 greater than the green spokes 20 of the first series 14. The molds -(2) are arranged in two rows 36, 38 that are immediately adjacent one another. As with the first series 14, the second series 16 could have any number of rows and these rows need not be immediately adjacent one another in other embodiments.
A third series 18 exists in the array and includes molds -(3) that are positioned within two rows 40, 42 that extend from one side of the platen 12 to the other. The molds -(3) of the third series 18 carry green spokes 20 that require a different amount of cure time in the platen 12 than do the green spokes 20 of molds -(1) and -(2). The green spokes 20 of the molds -(3) require a greater amount of time within the platen 12 to cure the green spokes 20 they carry than do the molds -(1) and -(2). As with the first and second series 12, 16, any number of rows of the third series 18 can be present and these rows may be in sequence with one another or may be separated by rows of other mold series 14 or 16.
Although three series 14, 16, 18 are shown, it is to be understood that any number of series of molds can be present in other embodiments, and each of these series includes green spokes 20 that require a different cure time in the platen 12. There may be from 4-6 series, from 7-10 series, from 11-15 series, or from 16-26 series in accordance with other exemplary embodiments. The rows 32, 34, 36, 38, 40, 42 are shown as extending across the width of the platen 12, but need not extend the entire way across in other embodiments. In this regard, although all of the rows 32, 34, 36, 38, 40, 42 are shown being filled with molds, it is to be understood that there may be gaps in the rows 32, 34, 36, 38, 40, 42 such that they do not include molds all the way across but instead have some empty slots. Further, the rows 32, 34, 36, 38, 40, 42 although shown as being horizontally extending could instead be vertically extending with respect to a view downward into the platen 12.
As used in the process, the molds of the first series 14 are labeled -(1) in which the “-” represents a mold of an unspecified number and the (1) represents the fact that this particular mold is a member of the first series 14. The molds of the second series 16 are labeled as having a designation -(2) and this signifies that the mold is of an unspecified number with the 2 meaning that this particular mold is a member of the second series 16. Likewise the molds of the third series 18 are labeled with a -(3) in which the “-” signifies a mold of an unidentified number and the (3) means it is a member of the third series 18 of molds. The molds in the intervention area 56 are not yet a member of any of the series 14, 16, or 18 and thus are simply given the designation (x), but will become one of the molds of the series 14, 16, or 18 once supplied with a green spoke 20 and put into the platen 12.
The method includes positioning a first mold of the first series 1(1) into the first row 32 so that it is, at the position shown in
Any device or method can be employed to move the molds from the first transport 58 to within the platen 12. As shown, each row 32, 34, 36, 38, 40, 42 is associated with its own linear actuator. The first series linear actuator 44, which could be a pneumatic or hydraulic cylinder, pushes molds into the first row 32, and the first series linear actuator 46 pushes molds from the first transport 58 to the second row 34. Second series linear actuators 48, 50 push molds into the third row 36 and the fourth row 38. Third series linear actuators 52, 54 push molds into the fifth row 40 and the sixth row 42. However, in other embodiments, a single linear actuator may move to the necessary row 32, 34, 36, 38, 40, 42 and push the mold from the first transport 58 into it. Still further, multiple linear actuators may be present but can be set up so that they are associated with some but not all of the rows 32, 34, 36, 38, 40, 42 such that one is associated with the rows 32, 34 of the first series 14, one is associated with the rows 36, 38 of the second series 16, and one is associated with the rows 40, 42 of the third series 18. In still other embodiments, a linear actuator is carried by the first transport 58 so that when the first transport 58 is next to the desired row, it is actuated to push the mold off of the first transport 58 and into the row 32, 34, 36, 38, 40, 42 adjacent the first transport 58. In this embodiment, the linear actuator moves with the first transport 58 and its position is thus adjustable relative to the platen 12.
The method can continue loading molds into the platen 12 and removing molds from the platen 12 in accordance with the necessary cure times of the various green spokes 20 being cured within the platen 12. For example, the platen 12 could be opened so that force is no longer applied to any of the molds within the platen 12, and three additional molds may be inserted into the platen 12.
The method can continue to add molds to the platen 12 and remove molds from the platen 12 depending upon the required cure time of the molds of the various series 14, 16, 18. The green spokes 20 of the first series 14 require the shortest amount of cure time so they are cycled through the platen 12 faster than the green spokes 20 in the molds of the second series 16 and the third series 18. In this regard, the molds in the first series 14 are inserted and removed faster than those of the second and third series 16, 18 so that they reach the right hand side of the platen 12 faster than those of the second and third series 16 and 18.
The cured spoke 22 in the mold 1(1) could be transported from the platen 12 via the second transport 60 to the mold open area 62. Here, the robot 30 or a human can open the mold 1(1), for instance by separating the top piece 24 from the bottom piece 26, and can demold the cured spoke 22 from the mold 1(1). The cured spoke 22 may then be placed by the robot 30 to the human onto the cured spoke transport 78 and transported away from the platen 12 station to the next station in the production process. The mold 1(1) that was just opened could then be moved to the intervention area 56 and its surfaces can be cleaned and prepared for acceptance of a new green spoke 20 for subsequent transport back into the platen 12 for curing.
The positioning of the molds in
A subsequent step in the curing method is illustrated with reference to
Although
The spokes 10 in the various series 14, 16, 18, 84, 86 require different amounts of curing time within the platin 12 and the transferring of the spokes 10 through the platin 12 can be timed with a bump cycle such that when a bump cycle takes place in the platin 12 the spokes 10 are transferred.
The method of curing thus utilizes molds that carry spokes 10 that may require different cure times. In other embodiments, the cure times of the spokes 10 may not be different from one another as used in the present method. Depending upon the cure times and the number of molds within the platen 12, it may be the case that some molds placed into the platen 12 are empty of green spokes 20 for curing but instead are put into the platen 12 for spacing purposes due to the timing of the cure times for the different series 14, 16, 18 in the array and for the number of mold spaces within the platen 12. As such, it is to be understood that not all of the molds within the platen 12 include a green spoke 10. Further, although described as having a single green spoke 20 within each one of the molds, it is the case that in some embodiments the molds put into the platen 12 may include 2, 3, 4, from 5-10, from 11-20, or from 21-30 green spokes 20 in other embodiments.
In some embodiments, the green spokes 20 of the first series 14 have a cure time within the platen 12 of 8 minutes, and the green spokes 20 of the second series 16 have a cure time within the platen 12 of 10 minutes, and the green spokes 20 of the third series 18 have a cure time within the platen 12 of 12 minutes. In some instances, the robot 30 could provide as much or as little automation as needed or desired in the method. For example, the robot 30 could open the molds (x), place the green spoke 20 within the mold (x), close the mold (x) with the green spoke 20 therein, and move the closed mold (x) with the green spoke 20 onto the first transport 58. In other arrangements, the opening and closing of molds (x) could be done by fixtures, or could be done manually. The cured spoke 22 could be demolded from the mold (x) by the robot 30 or by a human operator.
The various series 14, 16, 18 can undergo a cycle at set frequencies to allow the mold with the cured spokes 22 to be pushed out of the platen 12 by a mold having a green spoke 20. The opening of the platen 12 may also function simultaneously as a bump cycle in some instances as pressure is released from the platen 12 allowing air to escape. However, the cycle to move the molds need not constitute a bump cycle in all embodiments. If pressure from the platen 12 is not needed for the curing, the molds may still be put into the platen 12 for increased temperature. The platen 12 may have a top that moves up and down by the actuation of a piston, and the top of the platen 12 need not move the entire way up, thus less than the entire stroke of the piston, when inserting and removing molds 70 from within the platen 12. The top need only be moved up a distance short enough to allow the molds 70 to be pushed into and out of the platen 12. Opening of the platen 12 with less than its entire capability provides lower cycle time in the production process.
The present method allows for the curing of multiple spokes 10 with different cure laws in the same platen press 12. Also, spokes 10 having different sizes and/or cure laws can be changed during production with the simple removal and replacement of the mold 70 subassemblies into and out of the system. As such, different types of spokes 10, whether they be of different materials, sizes, or configurations, can be all molded at the same time within the same platen 12. The transport method of molds 70 into and out of the platen 12 minimizes the amount of piston stroke needed by the platen 12 and reduces temperature fluctuations of the molds 70 within the platen 12. In putting molds 70 into and out of the platen 12, a bump/breathe cycle can be utilized to allow air trapped within the molds 70 to escape. However, the movement of molds 70 in opening the platen 12 may or may not constitute a bump cycle as is used in some instances of molding with a platen 12. Although a single platen 12 level is shown and described, it is to be understood that the rows of molds 70 could be arranged in a multi-level platen 12 that has various floors positioned vertically higher and lower than one another.
The method can allow one to mold a certain type of spoke 10 with the first series 14, and then once the last mold -(1) of the first series 14 is removed, a spoke 10 of a second series 16 can be put into the same line as the molds -(1) that were creating the first series 14. As such, the line can be converted over in transition from spokes 10 of one size/configuration to spokes 10 of a different size/configuration. The embodiments illustrated show the different series 14, 16, 18 in different rows of the platen 12, but it is to be understood that the different series 14, 16, 18 could be put into the same row of the platen 12 in other embodiments to effect a transition in that particular row from one series 14, 16, 18 to the next.
Any type of mold 70 can be adapted for use with the present process. The molds 70 could be a single mold assembly or a multi-cavity mold assembly. Further, the molds 70 may be self-locking or otherwise capable of applying some force to the green spoke 20 therein and so that additional force can be imparted via the platen 12. The platen 12 could be a fixed platen 12 or a floating platen 12, and the molds 70 used may be floating platen molds 70 or fixed platen molds 70. The molds 70 could have top halves and bottom halves that move with one another into and out of the platen 12. Alternatively, some embodiments are possible in which one of the halves, for example the top half, of the mold 70 is fixed in the platen 12 while the bottom half of the mold 70 moves into and out of the platen 12.
While the present subject matter has been described in detail with respect to specific embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be apparent.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/063554 | 11/27/2019 | WO |