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Title:
MOLD WITH VOLUME COMPENSATION FOR SPOKE OF NON-PNEUMATIC TIRE
Document Type and Number:
WIPO Patent Application WO/2020/131378
Kind Code:
A1
Abstract:
A mold 810) for manufacturing a spoke for a non-pneumatic tire is provided that has first and second mold pieces (16, 22) with first and second engagement surfaces to engage the spoke. The first mold piece (16) has a void (20), and is movable relative to the second mold piece. A volume compensation feature (26) is carried by the first mold piece (16) and has a base that is located at the void. The volume compensation feature has a deflection plate (30) that engages the base, and has a non-deflected orientation and a deflected orientation. When the mold is closed the spoke engages the deflection plate and deflects the deflection plate relative to the first engagement surface so as to be in the deflected orientation.

Inventors:
WILSON BRIAN D (US)
BOHN JR (US)
Application Number:
PCT/US2019/064460
Publication Date:
June 25, 2020
Filing Date:
December 04, 2019
Export Citation:
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Assignee:
MICHELIN & CIE (FR)
WILSON BRIAN D (US)
BOHN JR CLAYTON (US)
International Classes:
B29D30/02; B29C33/00
Domestic Patent References:
WO2018125197A12018-07-05
WO2002087863A22002-11-07
WO2016108890A12016-07-07
Foreign References:
JPS57205126A1982-12-16
FR1076635A1954-10-28
US20170068670W2017-12-28
Attorney, Agent or Firm:
PIEROTTI, Neal (US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A mold for use in manufacturing a spoke for a non-pneumatic tire, comprising: a first mold piece having a first engagement surface configured for engaging the spoke, wherein the first mold piece has a void;

a second mold piece having a second engagement surface configured for engaging the spoke, wherein the first mold piece and the second mold piece are movable relative to one another; and

a volume compensation feature carried by the first mold piece, wherein the volume compensation feature has a base that is located at the void, and wherein the volume compensation feature has a deflection plate that engages the base, wherein the deflection plate has a non-deflected orientation and a deflected orientation;

wherein when the mold is closed the spoke engages the deflection plate and deflects the deflection plate relative to the first engagement surface so as to be in the deflected orientation.

2. The mold as set forth in claim 1, wherein the base is located completely within the void.

3. The mold as set forth in claim 1 or 2, wherein the deflection plate has a perimeter, and wherein the upper surface of the deflection plate is flush with the first engagement surface along at least a majority of the perimeter of the deflection plate in the non-deflected orientation.

4. The mold as set forth in any one of claims 1-3, wherein the upper surface of the deflection plate is flat when the deflected plate is in the non-deflected orientation.

5. The mold as set forth in any one of claims 1-4, wherein the deflection plate bends upon deflecting from the non-deflected orientation to the deflected orientation.

6. The mold as set forth in any one of claims 1-5, wherein when the deflection plate is in the deflected orientation the base fills the void a greater amount than when the deflection plate is in the non-deflected orientation such that the volume of the void is less in the deflected orientation and greater in the non-deflected orientation.

7. The mold as set forth in any one of claims 2-6, wherein the base is made of a material different than the deflection plate, the first mold piece, and the second mold piece; and

wherein the deflection plate is made of a material different than the first mold piece and the second mold piece.

8. The mold as set forth in claim 7, wherein the base is made out of a polymeric material, wherein the deflection plate is made out of spring steel, and wherein the first mold piece and the second mold piece are made out of aluminum or steel.

9. The mold as set forth in any one of claims 1-8, wherein the second mold piece has a second void, and further comprising a second volume compensation feature carried by the second mold piece, wherein the second volume compensation feature has a second base that is located at the second void, and wherein the second volume compensation feature has a second deflection plate that engages the second base, wherein the second deflection plate has a non-deflected orientation and a deflected orientation.

10. The mold as set forth in claim 9, wherein the first mold piece has a third void, and further comprising a third volume compensation feature carried by the third mold piece, wherein the third volume compensation feature has a third base that is located at the third void, and wherein the third volume compensation feature has a third deflection plate that engages the third base, wherein the third deflection plate has a non-deflected orientation and a deflected orientation.

11. The mold as set forth in any one of claims 1-10, wherein when the mold is closed a flat leg panel of the spoke is the portion of the spoke that engages the deflection plate and deflects the deflection plate relative to the first engagement surface so as to be in the deflected orientation.

12. The mold as set forth in any one of claims 1-11, wherein when the mold is opened after curing of the spoke the deflection plate springs back from the deflected orientation to the non-deflected orientation.

13. The mold as set forth in claim 12, wherein the deflection plate springs back from the deflected orientation to the non-deflected orientation due to elasticity of the materials making up the deflection plate and the base.

Description:
MOLD WITH VOLUME COMPENSATION FOR SPOKE OF NON-PNEUMATIC TIRE

FIELD OF THE INVENTION

[0001] The subject matter of the present invention relates to a mold for use in manufacturing a spoke used in the construction of a non-pneumatic tire. More particularly, the present application involves a mold that has a volume compensation feature for the reduction or elimination of flashing, and that reduces distortion of the molded spoke and allows for less precise manufacturing methods for green spoke components placed into the mold.

BACKGROUND OF THE INVENTION

[0002] 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 components of the non-pneumatic tire, it is known to combine together the spoke component products into a long form that is cut to the desired length. This cutting can be before or after curing of the product. Another known method of producing spokes involves placing the components of the spoke into 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. This pressure along with heat cures the components of the spoke to manufacture the product.

[0003] The spoke could be formed by a plurality of components, and it is possible that the control of mass per unit length of one or more of these components entering the mold could be off by as much as two or three percent. The excess material, or lack of material, of one or more of the components could result in the molded spoke being made in an unintended manner. Excess material may cause flashing of the molded part which will require labor and cost to clean off of the finished spoke. Excess material, or lack of material, of one or more of the components may result in distortion of the spoke architecture by having too much rubber flow to one area of the spoke, or by having one area of the spoke lack enough rubber to create its desired shape. It is generally the case that components of the spoke are provided with more, as opposed to less, material so that voids in the spoke are avoided upon molding. However, as previously stated imprecise manufacturing methods of the various components of the spoke may result in too much material being present in the green, uncured spoke components placed into the mold. A mold with a feature that functions to reduce or eliminate flashing, prevents the distortion of spoke architecture, and allows for less precise manufacturing methods of the uncured components supplied to the mold would be desirable. As such, there remains room for variation and improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] 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:

[0005] Fig. 1 is a side view of a non-pneumatic tire.

[0006] Fig. 2 is a perspective view of a spoke of a non-pneumatic tire in one embodiment.

[0007] Fig. 3 is a perspective view of a bottom half of a mold for molding a spoke of a non-pneumatic tire that has a volume compensation feature.

[0008] Fig. 4 is a perspective sectional view taken along line 4-4 of Fig. 3.

[0009] Fig. 5 is a cross-sectional view of a bottom half of a mold in an open configuration with the spoke components placed onto the bottom half.

[0010] Fig. 6 is a cross-sectional view of the bottom half and spoke of Fig. 5 in a closed position with the top half engaged thereon and pressure applied.

[0011] Fig. 7 is a cross-sectional view taken along line 7-7 of Fig. 6.

[0012] Fig. 8 is a cross-sectional view of an open mold with several volume compensation features in accordance with another exemplary embodiment.

[0013] Fig. 9 is a cross-sectional view of the mold of Fig. 8 in a closed position with pressure applied.

[0014] Fig. 10 is a perspective view of a mold with a volume compensation feature that has pressure applied via a lock rod arrangement.

[0015] The use of identical or similar reference numerals in different figures denotes identical or similar features.

DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] The present invention provides for a mold 10 for forming a spoke 12 of a non-pneumatic tire 14 that has a volume compensation feature 26 that allows for greater variability in the mass of components supplied to the mold 10. The volume compensation feature 26 provides an adjustability to the mold 10 volume so that additional mass of the components do not cause distortion of the resulting molded spoke 12 and so that flashing is reduced or eliminated. The volume compensation feature 26 has a base 28 and a deflection plate 30 that moves between a non-deflected orientation 34 and a deflected orientation 36 based upon whether the mold 10 is opened or closed and whether the spoke 12 in the mold 10 has or does not have excess material. If excess material is present and the mold 10 is closed the deflection plate 30 moves to the deflected orientation 36 so that additional mold 10 volume is present to accommodate the presence of the excess material. The resulting cured spoke 10 will maintain its desired spoke 10 architecture even though this excess material is present, and flashing will be eliminated or reduced since the excess material will be included in the added volume afforded by the deflected orientation 36.

[0018] Fig. 1 shows a non-pneumatic tire 14. The non-pneumatic tire 14 has an axis 54 at its center, and the radial direction extends from the axis 54. Tread is located on the outer exterior of a shear band 56 and extends all the way around the non-pneumatic tire 14 in the circumferential direction. The shear band 56 is located inward in the radial direction from the tread and likewise extends 360 degrees around the axis 54 in the circumferential direction. A series of spokes 12 engage the shear band 56 and extend inward in the radial direction from the shear band 56 to a hub 58 of the non-pneumatic tire 14. Any number of spokes 12 can be present, and their cross-sectional shape can be different from that shown. In some instances, between 64-80 spokes 12 are present in the non-pneumatic tire 14. The hub 58 is located inward from the spokes 12 in the radial direction and can be mounted onto a wheel of the vehicle. The spokes 12 at the top of the non-pneumatic tire 14 are in tension, and the spokes 12 at the bottom are in compression as the non-pneumatic tire 14 rests on the ground and as the non-pneumatic tire 14 turns in normal operation of the vehicle.

[0019] The spoke 12 is shown in perspective view in Fig. 2 and includes a pair of legs 60, 62 that have triangular shaped feet 66, 68. The central body of the spoke 12 is also made with a triangular shaped cross-section and is referred to as a nose 64. The spoke 12 can be molded out of a single material, or may be made from a plurality of materials in some embodiments. Multiple layers of material can be placed onto one another and then positioned into the mold 10 for curing. It is to be understood that the shape and size of the spoke 12 formed by the mold 10 can be varied in accordance with different exemplary embodiments, and that a variety of spoke 12 configurations are possible. Materials making up the spoke 12 may include rubber, urethane, and/or polyurethane in accordance with different exemplary embodiments. The spoke 12 extends from a first end to a second end, to achieve a depth of the spoke 12, and may have an extension from end to end greater than, less than, or the same as the height of the spoke 12.

[0020] Fig. 3 shows a first mold piece 16 of the mold 10 in an open position without the spoke 12 located thereon. The first mold piece 16 can be made of any suitable material such as steel or aluminum and may feature apertures or other recesses for connection to a second mold piece 22 or pressing/clamping member. The first mold piece 16 is complimentary to a second mold piece 22 and both are designed for relative movement towards and away from one another. The first mold piece 16 has a first engagement surface 18 shaped and sized for engagement with the green spoke 12 to cause the green spoke 12 to be molded as desired. It is to be understood that an uncured spoke 12 is often referred to as a “green” spoke 12. The first mold piece 16 includes a volume compensation feature 26 that can be located at the first engagement surface 18. The volume compensation feature 26 has a deflection plate 30 with an upper surface 32 that engages the green spoke 12 when the green spoke 12 comes into contact with the first engagement surface 18. The deflection plate 30 has a perimeter 70 at the first engagement surface 18 that is rectangular in shape. In other embodiments the perimeter 70 need not be rectangular in shape but could be variously shaped such as being square, triangular, oval, or circular in shape.

[0021] The upper surface 32 at the entire perimeter 70 could be flush with the adjacent first engagement surface 18. In some embodiments, the upper surface 32 is flush with the first engagement surface 18 along a majority of the perimeter 70, but not along the entire perimeter 70. In yet other embodiments, the upper surface 32 is flush with the first engagement surface 18 along a minority of the perimeter 70. In still further embodiments, the upper surface 32 is not flush at all with the first engagement surface 18 along any portion of the perimeter 70. The upper surface 32 does not extend along the entire area the spoke 12 engages, but is only a portion of the area engaged by the spoke 12 with the first engagement surface 18 making up the rest of the area at the first mold piece 16 that engages the spoke 12. The upper surface 32 may extend the entire depth of the spoke 12 and thus extend from one end of the spoke 12 to the other. The upper surface 32 may be flat in the non-deflected orientation 34 illustrated in Fig. 3. The upper surface 32 can be positioned at a portion of the spoke 12 to be cured that is desired to be a flat portion of the spoke 12.

[0022] With reference now to Fig. 4, a sectional view of the first mold piece 16 of Fig.3 is illustrated. The first mold piece 16 has a void 20. The volume compensation feature 26 includes a base 28 that is at the void 20. The base 28 may be located entirely within the void 20 so that the base 28 does not extend to the first engagement surface 18. The void 20 and base 28 may have the same cross-sectional shape, and in the embodiment shown are both rectangular in cross-sectional shape. The base 28 directly engages the deflection plate 30 on a side of the deflection plate 30 opposite of the upper surface 32. The base 28 may be connected to the deflection plate 30, or the base 28 can simply be in contact with the deflection plate 30 but not directly attached to the deflection plate 30.

[0023] The base 28 may be made out of a material different than that making up the deflection plate 30 in some embodiments. In some instances, the base 28 is made out of a polymeric material and the deflection plate 30 is made out of spring steel material. In other embodiments the base 28 is made out of a polyurethane material. The base 28 may be composed of silicone adhesive with zinc oxide as a thermally conductive filler. The material composing the base 28 may be COOLTHERM ® MT-220 thermally conductive adhesive supplied by Lord Corporation having headquarters at 111 Lord Drive, Cary, North Carolina, USA. The deflection plate 30 may be made of AISI 1095 spring steel, or may be made out of Beryllium Copper UNS C17300 for higher heat transfer. The base 28 may be selected to be a material that has the same or similar thermal conductivity characteristics as the material making up the first mold piece 16. In a similar manner, the material making up the deflection plate 30 may be selected so as to be a material with the same or similar thermal conductivity characteristics as the material making up the first mold piece 16. By selecting materials that are close in thermal conductivity the first mold piece 16, the base 28 and the deflection plate 30 can transfer heat into the spoke 12 in a consistent manner. Still further, these elements may have similar or the same thermal conductivity properties as the second mold piece 22, and any volume compensation features of the second mold piece 22, and any other mold pieces employed in the mold 10 so that the spoke 12 receives heat in a uniform and consistent manner during curing. However, it is to be understood that the elements 16, 28 and 30 need not all have the same or similar thermal conductivity properties to one another or to other portions of the mold 10 in other arrangement of the mold 10.

[0024] In use of the mold 10, the green spoke 12 is placed onto one of the first or second engagement surfaces 18, 24 while the first and second mold pieces 16, 22 are in an open position. Fig. 5 is a cross-sectional view of the first mold piece 16 in accordance with one exemplary embodiment in the open position with a green, uncured spoke 12 located on the first engagement surface 18. The uncured spoke 12 is made of a number of different tissues that each themselves may include various materials such as rubber, cord, polyurethane, metal, any polymeric material or any other material. The various components can be assembled directly on the first engagement surface 18 or can be preassembled and simply moved onto the first engagement surface 18. Alternatively, some of the components can be present on the second engagement surface 24 and moved into engagement with those on the first engagement surface 18 when the mold 10 is closed. The spoke 12 shown in Fig. 5 has a nose 64 made primarily out of two separate tissues. The spoke 12 also has a pair of legs 60, 62 that are flat that extend into and between the nose 64 and the opposite feet 66, 68. Although four components are shown, as previously discussed any number of components can be present in the uncured spoke 12 in other arrangements.

[0025] The uncured spoke 12 is placed onto the first engagement surface 18 and the deflection plate 30 engages the component making up the leg 62, but is not deflected as minimal force is applied to the deflection plate 30 via the weight of the spoke 12. The deflection plate 30 is positioned in a non-deflected orientation 34 when the mold 10 is open. The first engagement surface 18 also engages the spoke 12, and engages the spoke 12 a greater surface area than that of the surface area of engagement of the deflection plate 30 with the spoke 12. In the non-deflected orientation 34 of the deflection plate 30 the base 28 is at an initial at rest position and does not receive compressive forces by the deflection plate 30. However, based upon the orientation of the base 28 and deflection plate 30, the base 28 could experience some compressive force or other force from the deflection plate 30 even when the deflection plate 30 is in the non-deflected orientation 34. The upper surface 32 is flat and the portion of the spoke 12 that engages the upper surface 32, which is the panel making up the leg 62, is likewise flat at the upper surface 32. Variations of the shape of the portion of the uncured spoke 12 engaging the upper surface 32 are possible such that this portion need not be flat. In the non-deflected orientation 34 the upper surface 32 is flush with the first engagement surface 18 along at least a majority of the perimeter 70. [0026] The next step of the curing process may involve the use of a press 72 that has one or more hydraulic cylinders that actuate to force the top, second mold piece 22 down onto the bottom, first mold piece 16 with the green spoke 12 between the first mold piece 16 and second mold piece 22. Fig. 6 shows the press 72 with the mold 10 in the closed position. This compression causes some squeezing and deformation of the green spoke 12 into the desired final form. After the squeezing by the press 72, or simultaneously therewith, a lock 74 can be applied to the mold 10 to lock it in the squeezed position. The cylinder force of the press 72 can be released and the mold 10 will remain in the squeezed position so that the green spoke 12 in the mold 10 still feels compressive forces even with the compression of the press 72 released. Any mechanism may be employed to lock the mold 10 in the squeezed position. Fig. 6 illustrates two arms on either side of the mold 10 that pivot from the second mold piece 22 and engage the bottom of the first mold piece 16. The arms can pivot as the second mold piece 22 is pressed against the first mold piece 16. Alternatively, the first and second mold pieces 16, 22 could be first pressed against one another and then subsequently the lock 74 can engage to hold the mold pieces 16, 22 against one another with the pressure applied. As stated, the lock 74 can be variously configured and need only be capable of holding the two mold pieces 16, 22 together after they have been pressed together by the press 72.

[0027] The second mold piece 22 can be moved relative to the first mold piece 16 and the spoke 12 resting upon the first engagement surface 18 until the second mold piece 22 engages the spoke 12 and the spoke 12 is compressed between the first engagement surface 18 and the second engagement surface 24. The first and second mold pieces 16, 22 are thus moved into the closed position, and in this closed position certain portions of the first and second mold pieces 16, 22 can touch one another. However, in other arrangements, no portion of the first mold piece 16 contacts the second mold piece 22 when the mold 10 is closed. When the mold 10 is closed and the spoke 12 is compressed, if there is excess material in any one of the components of the uncured spoke 12 the volume compression feature 26 may deflect so that extra space is made for this extra material. If extra material is present, pressure applied onto the spoke 12 will cause the spoke 12 to push on the upper surface 32 to cause the deflection plate 30 to move from the non-deflected orientation 34 to the deflected orientation 36 illustrated in Fig. 6. In the deflected orientation 36 the deflection plate 30 bends inward towards the void 20. The ends 76 of the deflection plate 30 are nested within grooves of the first mold piece 16 so they do not bend or move relative to the first mold piece 16 when the deflection plate 30 moves into the deflected orientation 36.

[0028] Movement of the deflection plate 30 into the deflected orientation 36 may cause a corresponding deflection of the base 28 so that the volume of the void 20 is reduced in the deflected orientation 36 as compared to the non-deflected orientation 34. In other instances, the base 26 could be made of a material that includes voids so that movement of the deflection plate 30 into the base 26 closes these voids so that the base 26 absorbs some or all of the movement of the deflection plate 30 so that the base 26 does not move into the void 20 such that the void 20 is the same volume both in the non-deflected orientation 34 and the deflected orientation 36. Movement into the deflected orientation 36 adds additional volume to the space formed by the first and second mold pieces 16, 22 and if the leg 62 was provided with extra material then this material will flow into this extra space at this point so that flashing produced by the molding process is reduced or eliminated. Also, since extra material in the leg 62 is moved into this added space, the extra material will not move into other areas of the spoke 12 so that distortion of the architecture of the spoke 12 is prevented. For instance, the extra material could have been pushed into the foot 68 and changed the shape of the foot 68 if the volume compensation feature 26 were not present. Since the volume compensation feature 26 compensates for errors in the volume of material in components supplied to construct the green spoke 12, less precise manufacturing methods for the green spoke 12 components may be allowed to be employed saving both time and money in the construction of the spoke 12 along with compensating for any errors of extra material.

[0029] The volume compensation feature 26 can be located at a portion of the spoke 12 that is flat such that the upper surface 32 engages a flat portion of the spoke 12. However, other arrangements are possible in which the volume compensation feature26 is at a position in the mold 10 in which the upper surface 32 engages portions of the spoke 12 that are not flat, for example the nose 64. However, in some arrangements of the mold 10 all upper surfaces 32 present only engage flat portions of the spoke 12 and do not engage the spoke 12 or any other curved portions of the spoke 12. The flat area of the upper surface 32 and the deflection of the deflection plate 30 causes the extra material of the leg 62 to maintain a generally flat shape in the leg 62 so that the leg 62 will not be distorted. The extra material may cause a slight convex bulge in the leg 62 so that a resulting completely flat leg 62 does not result. The slight convex bulge may not significantly interfere with the architecture of the spoke 12 so that it will function in its initially intended manner. Also, the size of the leg 62 may allow for any excess material placed into it by the volume compensation feature 26 to be absorbed over its entire length and thus negligible in the leg 62 in the cured spoke 12.

[0030] Fig. 7 is a cross-sectional view along line 7-7 of Fig. 6 and shows the depth wise features of the volume compensation feature 26. The ends 76 of the deflection plate 30 remain undeflected in the non-deflected orientation 34. The ends 76 are nested within notches of the first mold piece 16 and can be retained therein through adhesives, mechanical fasteners, an interference fit, geometry of the first mold piece 16 into which the ends 76 are fit, or through any other means. Between the ends 76 the deflection plate 30 is deflected in the deflected orientation 36 so as to be below the ends 76 and the material of the leg 62 fits into this deflected space. The base 28 extends the width of the void 20, and the deflection plate 30 extends beyond the depths of the void 20 and the base 28 in both directions. It is to be understood that other arrangements of the volume compensation feature 26 are possible that are different than the embodiment disclosed in the figures. For instances, the volume compensation feature 26 can be made with a coil spring base 28 that engages the deflection plate 30 on one end and the first mold piece 16 within the void 20 on an opposite end. Pressure on the upper surface 32 causes compression of the coil spring base 28 which causes it to move further into the void 28 to thus move the deflection plate 30 into the void 28 to present space for the extra material to fill. Removal of force on the upper surface 32 allows the coil spring base 28 to push back outward so that the deflection plate 30 moves in a linear manner back to the non-deflected orientation 34. The deflection plate 30 may thus not bend in this arrangement, but instead slide in a linear manner towards/into the void 20 and out of/away from the void 20.

[0031] The spoke 12 will have pressure and heat applied for an amount and time sufficient to cure the green spoke 12 and produce a cured spoke 12. The base 28 and deflection plate 30 are preferably made out of materials that has the same, or as close as possible, thermal conductivity The cured spoke 12 is shown in Fig. 6 as having all of its components merge into a single layer, but it is to be understood that even after curing the various components and layers of the spoke 12 may still be visible. The mold 10 can then be opened so that the first and second mold pieces 16, 22 are moved away from one another, and the spoke 12 can be demolded from either the first mold piece 16 or the second mold piece 22. Release of pressure on the deflection plate 30 causes the deflection plate 30 to spring back from the deflected orientation 36 back to the non-deflected orientation 34. This spring back may be accomplished due to the material making up the deflection plate 30 being a high yield strength material that seeks to return to its normal at rest position once an applied force and bending is removed. Return to the non-deflected orientation 34 will also cause the base 28 to move back to its position in the non-deflected orientation 34 as shown in Fig. 5. The base 28 is also made of a material capable of returning to its normal, at rest position once the force is removed. The force can be removed once the spoke 12 is move out of engagement with the upper surface 32, or the force can be removed once the mold 10 is opened so that the first and second mold pieces 16, 22 are move away from one another into the open position so that pressure is removed from the spoke 12. As such, the spring back to the non-deflected orientation 34 can take place even when the spoke 12 is on the first engagement surface 18 and engages the upper surface 32. Alternatively, the spring back may only take place once the spoke 12 is disengaged from the upper surface 32. The return of the deflection plate 30 to the non-deflected orientation 34 from the deflected orientation 36 returns the first mold piece 16 back to its original starting position and a new uncured spoke 12 can be placed thereon for subsequent curing.

[0032] The mold 10 has been shown and described with but a single volume compensation feature 26 located therein. It is to be understood that any number of volume compensation features 26 can be present in the mold 10. The volume compensation features can be found in only one of the mold pieces 16 or 22, or can be found in both of the mold pieces 16 and 22. Fig. 8 shows an alternate embodiment in which the first mold 16 has four volume compensation features, and in which the second mold 22 has two volume compensation features. The first volume compensation feature 26 is configured as previously described and is located at the leg 62 to receive any extra material at this point. The second volume compensation feature 40 is located at the second mold piece 22 and includes a second base 42 and a second deflection plate 44 arranged as previously discussed regarding base 28 and deflection plate 30. The second mold piece 22 has a second void 38 and the base 28 is located at this second void 38. The second volume compensation feature 40 is located at the leg 60 and receives any excess material of this component of the spoke 12. The second volume compensation feature 40 functions in the same way as the volume compensation feature 26 and a repeat of this information is not necessary.

[0033] A third volume compensation feature 48 is included in the mold 10 and is in the first mold piece 16. The third volume compensation feature 48 has a third deflection plate 48 and a third base 50 located at a third void 46 in the first mold piece 16. The third volume compensation feature 48 works in a manner similar to the volume compensation feature 26 as previously discussed. The third volume compensation feature 48 is located at the foot 68 and receives excess material present in the component(s) of the uncured spoke 12 making up the foot 68. The upper surface of the third deflection plate 52 engages a flat section of the foot 68 and deflects inward should there be excess material in the foot 68. An additional fourth volume compensation feature 78 is present in the second mold piece 22 and is located at the leg 62. The leg 62 is adjacent on opposite sides to the volume compensation feature 26 and the fourth volume compensation feature 78 so that excess material in the leg 62 can be inserted into either of the features 26, 78 on opposite sides of the flat leg 62. A fifth volume compensation feature 80 is also included and is in the first mold piece 16 at the leg 60. The fifth volume compensation feature 80 is opposite the second volume compensation feature 40 with the leg 60 between them and excess material, if present, from the leg 60 can be received within the second and/or fifth volume compensation features 40, 80. A sixth volume compensation feature 82 is in the first mold piece 16 at the foot 66 and receives extra material from the foot 66 during molding.

[0034] The uncured spoke 12 is shown as being located on the first engagement surface 18 when the mold 10 is in the open position. The second mold piece 20 is moved to the first mold piece 16 to close the mold as shown in Fig. 9. Excess material from the spoke 12 is pressed against all of the volume compensation features 26, 40, 48, 78, 80, 82 and they are moved into the deflected orientations to accommodate this excess material as shown. The placement of volume compensation features on opposite sides of the leg 60 and of the leg 62 may allow for reduced distortion of the shape of the legs 60, 62 after curing because excess material could be located in both of these features so that the excess material is not completely focused on one side of the leg 60, 62. In Fig. 9 the excess material is shown as deflecting and moving into all of the volume compensation features 26, 40, 48, 78, 80, 82. In other instances, the placement of the excess material may be such that it flows into some of the volume compensation features but not others so that some but not all of the volume compensation features of the mold 10 are deflected. Also, the amount of force needed to deflect the individual volume compensation features 26, 40, 48, 78, 80, 82 could be varied so that some of them deflect before others during curing. Once the spoke 12 is cured, the mold 10 can be opened and the cured spoke 12 removed, and the volume compensation features 26, 40, 48, 78, 80, 82 can spring back to their non-deflected orientations so that a new spoke 12 can be inserted and cured. [0035] The functioning of the mold 10 has been described in that if the volume compensation feature 26 is next to the leg 62 and the leg 62 includes additional material then it is accommodated by the volume compensation feature 26. However, this need not always be the case. It is possible that if extra material is present in foot 66, then this excess material will cause material to flow into the volume compensation feature 26 (that is at the leg 62) even though this extra material is not at the leg 62 or at the volume compensation feature 26. The rubber or other material can flow within the mold 10 or otherwise force material into the volume compensation feature 26 that is remote therefrom. As such, it may be the case that a single volume compensation feature 26 is sufficient for handling all of the excess material. Any number of volume compensation features can be present in the mold 10 in accordance with various exemplary embodiments.

[0036] The mold 10 can include other features to effect molding of the spoke 12. Fig. 10 shows one of several different possible arrangements in which the mold 10 has lock down features that allow the mold 10 to be closed without the need to have a press 72 apply a force thereon during heating of the spoke 12 in the mold 10. The arrangement shown in Fig. 10 can be that as shown and described in PCT application US2017/68670 filed December 28, 2017 titled“Mold for Manufacturing a Spoke for a Non-pneumatic Tire”, the contents of which are incorporated by reference herein in their entirety for all purposes. The portion of the mold 10 that rigidly holds the second mold piece 26 has a series of spring loaded lock rods 84 that each have a lock element depression 86. When the second mold piece 22 is moved into engagement with the first mold piece 16 to close the mold 10, the lock rods 84 move into the illustrated openings. A lock element 88 is present and is actuated by the two lock element actuators 90 and 92 in a linear direction. Actuation of the lock element 88 causes it to be placed into the lock element depressions 86 to capture the lock rods 84 and hold the first and second mold pieces 16, 22 in the closed configuration. The closed mold 10 with the spoke 12 therein can then be transported into an oven and heated to cure the spoke 12 without the need for a press 72 to apply a constant force to the mold 10 due to the fact that the lock rods 84 are locked to the lock element 88 to mechanically apply closing force to the mold 10. To open the mold pieces 16, 22, the other one of the lock element actuators 90 or 92 is actuated to move the lock element 88 in the opposite direction to move it out of the lock element depressions 86 to release the lock rods 84 so that the mechanical closing force on the mold pieces 16, 22 is released. Although described as using the locking arrangement of Fig. 10, it is to be understood that a press 72 or other closing arrangement can be provided with the mold 10 to effect opening and closing and eventual curing of the spoke 12 in other embodiments. As such, other embodiments are possible in which the locking arrangement is not used, but instead the mold 10 is closed through the use of a platen press 72 and heat and pressure is applied while the platen press applies the hold down force.

[0037] The location of the volume compensation feature 26 could be at any portion of the spoke 12 and need not be at one of the legs 60, 62 in other embodiments. The volume compensation feature 26 can correct for poor control of mass per unit length of material fed into the spoke 12 components. In some manufacturing methods, this volume variation may be from 2 to 3 percent on tissues entering the mold 10. To accommodate this, the spoke 12 components should be made at a 1 percent volume variation to avoid flashing and spoke 12 architecture distortions. With the volume compensation feature 26 this tolerance can be relaxed to the 2 to 3 percent range so that the components making up the parts of the spoke 12, such as the legs 60, 62, feet 66, 68, and nose 64, may each be made up to 2 percent or up to 3 percent larger than design planning. In molding, it is desired to error on having too much material in the part to be molded, rather than not enough, so that voids within the molded part are avoided.

[0038] 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.




 
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