Abstract
A mould comprises a lining, having a lining body (2), and at least one moulding element (1) that is articulated with respect to the lining body, a cylindrical part (10) constituting a rotation axis (X) and a moulding part (11) secured to the cylindrical part (10). The cylindrical part (10) is placed in a cylindrical hole (20) arranged in the lining body (2) made from the same material as the moulding element (1). The moulding element (1) is of one piece, and is non-separable from the lining body (2).
Claims
1. A mould comprising a lining, having a lining body, and at least one moulding element that is articulated with respect to the lining body, said moulding element comprising a cylindrical part constituting a rotation axis and a moulding part secured to the cylindrical part, wherein the cylindrical part is placed in a cylindrical hole arranged in the lining body made from the same material as the moulding element, and wherein said moulding element is of one piece.
2. The mould according to claim 1, comprising means for the abutment and/or immobilization of the moulding element.
3. The mould according to claim 2, wherein the lining body has a surface arranged inside the mould and wherein one of the abutments is perpendicular to the surface of the lining body and the other is inclined.
4. The mould according to claim 1, wherein the cylindrical hole and the cylindrical part of the moulding element have a circular profile.
5. The mould according to claim 1, wherein the cylindrical hole and the cylindrical part of the moulding element have an oval profile.
6. The mould according to claim 1, characterized in that wherein the moulding element is arranged at the end of a sipe blade and wherein this end has a cylindrical exterior shape.
7. The mould according to claim 1, wherein the cylindrical hole has a closed profile and wherein the moulding element has a longitudinal recess in which a cylindrical part of the lining body is inserted.
8. The mould according to claim 1, wherein the cylindrical element is extended on each side by a cylindrical spigot that acts as a hinge.
9. A method of manufacturing an articulated moulding element of a mould according to claim 1, wherein the moulding element and the lining body are produced as a single piece by powder laser sintering during one and the same manufacturing operation and form a non-separable connection.
10. The method of manufacture according to claim 9, wherein an at least 0.1 mm thickness of non-fused powder is left between the articulated moulding element and the lining body.
Description
[0019] FIG. 1 depicts a view in longitudinal section of an articulated moulding element according to the invention,
[0020] FIG. 2 is a view in transverse section of the articulated moulding element of FIG. 1,
[0021] FIG. 3 is a view in cross section of an articulated moulding element according to a second alternative form of the invention,
[0022] FIG. 4 is a view in transverse section of the articulated moulding element of FIG. 3,
[0023] FIG. 5 is a view in cross section of an articulated moulding element according to a third alternative form of the invention,
[0024] FIG. 6 is a schematic view of a first alternative form of limiting of the moulding element according to the invention,
[0025] FIG. 7 depicts a schematic view of a second alternative form of limiting of the moulding element according to the invention,
[0026] FIG. 8 is a schematic view of a third alternative form of limiting of the moulding element according to the invention,
[0027] FIGS. 9 and 10 are two examples of positions of the moulding element according to the invention,
[0028] FIGS. 11 and 12 are two examples of positions of the moulding element according to the invention with a first example of an immobilizing system,
[0029] FIGS. 13 and 14 are two examples of positions of the moulding element according to the invention with a second example of an immobilizing system,
[0030] FIGS. 15 and 16 are views from above along the length of the sipe blade,
[0031] FIGS. 17 and 18 are views along the height of the sipe blade,
[0032] FIG. 19 is a view in transverse section of the moulding element manufactured according to the method,
[0033] FIG. 20 is a view in transverse section of another type of moulding element,
[0034] FIG. 21 is a view in profile of a mould with detail of a sipe blade in the mould-filling position,
[0035] FIG. 22 is a view in profile of the mould of FIG. 21 with the detail of the sipe blade in the demoulding position.
[0036] The example illustrated in FIGS. 1 and 2 shows a lining comprising an articulated moulding element 1 and a lining body 2 in which a cylindrical hole 20 is pierced. The moulding element 1 comprises a cylindrical part 10 arranged in the cylindrical hole 20 and a moulding part 11 which in this instance is rectilinear, starting from the cylindrical part 10. The cylindrical part 10 rotates about an axis X and on each side has cylindrical spigots 100 acting as a hinge and each collaborating with an orifice 26 that extends the cylindrical hole 20.
[0037] The example of FIGS. 3 and 4 shows an articulated moulding element in which the moulding part 11 has a recess 12 in which a peripheral part 21 of the lining body 2 can slide.
[0038] In the example of FIG. 5, the moulding element 1 has a cylindrical part 10 pierced with a hole 101 in which a rod 22 of axis X is inserted and secured to the lining 2.
[0039] In FIG. 6, the rectilinear part 11 is halted between two abutment stops 23 and 24 arranged on a surface of the lining 2 that is arranged on the interior side of the mould.
[0040] In FIG. 7, the cylindrical hole 20 of the lining body 2 and the cylindrical part 10 of the moulding element 1 have an oval profile and so when the moulding element 1 turns, the longest part 100 of the cylindrical part 10 will come into abutment against two sides 200 and 201 of the cylindrical hole 20.
[0041] In FIG. 8, the moulding element 1 has a counter abutment stop 13 which will be halted by two abutment stops 202 and 203 positioned inside the cylindrical hole 20. For better retention, it is possible to conceive of several abutment stops and counter abutment stops in the manner of meshing gears or a splined shaft.
[0042] FIGS. 9 to 18 show how the invention can be used in a tire manufacturing mould.
[0043] FIG. 9 illustrates an example of a position of the mobile element 1 on a moulding bar 3 for creating a tire groove, the moulding part 11 of the moulding element 1 in this instance is a sipe blade for moulding a sipe in the said tire. FIG. 10 shows a second position of the moulding element 1.
[0044] As in FIG. 9, in FIGS. 11 and 12, each mobile element 1 is prevented from rotating by a pin 4.
[0045] Likewise in FIGS. 13 and 14, the moulding elements 1 have teeth 14 which are equivalent to counter abutment stops, distributed over the entire periphery of the cylindrical part 10, these collaborating with abutment stops 204 arranged in the cylindrical hole 20, all of this constituting meshing gears or a splined shaft which may have the ability to slide so that the sipe blade can be removed and then reintroduced at another angle of inclination that will allow immobilization of the moulding part 11 of the moulding element 1.
[0046] FIG. 15 shows a plan view from above of the moulding bar 3 in the mould with a sipe blade 5 produced in the conventional way. FIG. 16 illustrates an articulated moulding element 1 placed at the end of the sipe blade 5. In this way, the tread pattern of the tire will be able to have sipes that follow broken lines and the tread pattern will be able to be modified during tire manufacture, with an immobilizing system.
[0047] FIG. 17 shows, in cross section, a bottom of the lining body 2 with a sipe blade 5 arranged on this bottom in the conventional way. In FIG. 18, the sipe blade 5 is surmounted by an articulated moulding element 1 placed at the upper part. It is thus easier to demould the tire since the mobile element 1 affords a certain degree of flexibility to the upper part of the sipe blade 5. The sipe blade may comprise one or more mobile elements so as to create an L-shaped sipe or a Y-shaped sipe which are shapes that are already known.
[0048] Manufacture of the moulding element 1 on the lining body 2 is performed in a single piece by powder laser sintering. In FIG. 19, the cylindrical part 10 is for exemple approximately 0.2 mm distant from the cylindrical hole 20, so powder 7 remains trapped between the cylindrical part 10 and the cylindrical hole 20 of the lining body after the laser sintering operation has been performed and this powder is then blown out in order to obtain the articulated moulding element 1.
[0049] It is also possible to have some of the powder semi-fused through the diffusion of heat, here near the bottom of the space between the two components, this powder constituting a slender connection 70 which connects the cylindrical part 10 to the inside of the cylindrical hole 20. This slender connection 70 is broken through action on the moulding element 1. In the example illustrated in FIG. 20, when the clearance is too small, during the sintering through diffusion of heat the connection is at the bottom because of gravity and this makes the mobile element rest on the bottom of the cylindrical cavity.
[0050] FIG. 21 shows an example of a mould with its lining which in this instance comprises two moulding elements 1 at the time of moulding. As can be seen, the mould has a rounded shape and the moulding elements 1 are, for example, perpendicular to the surface of the lining at the time of moulding since the tread patterns are perpendicular (which is not necessarily always the case) to the surface of the tire. The pressure exerted on the sipe blades at the time of the moulding of the rubber is great which means that the moulding parts 11 of the moulding elements 1 are pushed into an inclined position (into abutment), a cutout 110 being provided, for example, on one side of the moulding part 11 so as to limit the inclination of the moulding element 1. This cutout 110 collaborates with, for example, an elevation 25 of the surface of the lining 2.
[0051] FIG. 22 shows the mould of FIG. 21 at the time of demoulding. Once the rubber has hardened or become vulcanized, because demoulding is performed in a movement perpendicular to the mould rather than to the rounded surface of the lining, the moulding element 1 will rotate in the demoulding direction to make such demoulding easier, which means to say in this instance will rotate to vertical.
[0052] Other applications of the mobile element 1 are possible without departing from the scope of the present invention.
