Method and apparatus for applying a predetermined amount of material

Abstract

A method and apparatus for applying a quantity of sealing material to a closure cap of a container to form a gasket, wherein an annular quantity is separated from a flow of plasticized material and deposited at the base of the cap, the plasticized material being fed through a channel until it reaches a material outlet extending along a circumferential direction, the annular quantity including at least one differentiated portion whereby a radial cross-section at the differentiated portion of the annular quantity differs from a radial cross-section at another portion of the annular quantity, where "radial" is understood to refer to an axis about which the annular quantity extends circumferentially, and the presence of the differentiated portion reduces the risk of air pockets forming between the sealing material and the cap.

Description

[Technical Field]

[0001] In particular, the present invention relates to a method and apparatus for applying a predetermined amount of material, such as a sealing material, by separating a predetermined amount of material from a continuous flow of material plasticized by extrusion and applying the separated predetermined amount to a surface of an object, such as the inside of a cap for closing a container. [Background technology]

[0002] In particular, but not exclusively, the invention can be used to apply an annular quantity of material (in particular a sealing material) to a surface, for example to form an annular gasket on an object, such as the inside of a cap (made of metal or plastic) for closing a container, or to apply an annular quantity of material to a flat element (e.g. a disk), in particular made of metal or plastic, which has a sealing function and which is subsequently inserted into a more complex device, or to apply an annular quantity of material (in particular having a sealing function), for example to a cardboard element intended to form a container or part of a container, or directly onto, for example, a plastic or metal container, or to insert an annular quantity of material directly into a mold from which an object (e.g. an annular object), in particular having a sealing function (e.g. a plug consisting of a plastic wall and a central metal disk with a gasket obtained from the annular quantity), or an object having a function different from a sealing function, can be obtained.

[0003] JP 06-312762A, US 2012 / 0171381A1, US 2017 / 0239848A1, and US 2020 / 0376724A1 disclose coating methods as described in the preamble of claim 1, in which the radial cross section of the separated annular predetermined volume is constant over the entire circumferential range of the predetermined volume.

[0004] One of the challenges in the prior art is to apply an annular quantity of material (particularly a sealing material suitable for forming a gasket) to an object, particularly the base of the object (e.g., a cap for closing a container) and inside the annular wall of the object, without forming air pockets between the annular quantity and the object, particularly in the transition area between the base of the object and the annular wall of the object. Summary of the Invention [Problem to be solved by the invention]

[0005] One object of the present invention is to propose a method and / or device that allows overcoming the above-mentioned problems of the prior art.

[0006] One object of the present invention is to provide an alternative coating method and / or coating apparatus to the prior art.

[0007] One advantage is that it provides a structurally simple and inexpensive device for applying a circular amount of material to the surface of an object, particularly to form a gasket on a closure cap.

[0008] One advantage is that a predetermined annular amount of sealing material is applied to form a gasket on the base of the cap for closing the container and inside the annular wall of the cap without leaving an air pocket in the transition area between the base and the annular wall of the cap.

[0009] These objects and advantages, as well as other objects, are achieved by methods and / or apparatus according to one or more of the claims set out below. [Means for solving the problem]

[0010] In one embodiment, an application method, particularly an application method for applying an annular quantity of sealing material to the inside of a closure cap of a container to form a gasket, includes steps of separating the annular quantity from a flow of plasticized material and depositing the annular quantity on an object, wherein the plasticized material is fed through a channel until it reaches a material outlet extending along a circumferential direction, and the separated annular quantity includes at least one distinguished portion, the distinguished portion being understood to be a radial portion of the distinguished portion that is different from a radial portion of another portion of the annular quantity, where ``radial'' is understood to refer to an axis about which the annular quantity extends circumferentially.

[0011] The separated annular predetermined amount may in particular include a plurality of continuous portions or segments of material (e.g., three, four, five, or six continuous portions or segments of material), each extending along a circumferential arc (e.g., arc-shaped portions or segments of a toric crown) with an equal number of differentiated portions interposed therebetween, each containing material without cavities, the cavities being located in the space defined between two continuous portions or segments of material. Each continuous portion or segment of material may be formed as an arc having a circular sector with an angular extent of more than 30°, or more than 45°, or more than 60°. A continuous portion or segment of material may have a constant radial cross-section over its entire length or circumferential extent.

[0012] Each cavity in each differentiated portion may occupy all of the space defined between two successive portions or segments of material, such that there is an empty space between the two successive portions or segments of material where no material is present, or there may be a bridge or rib of material between the two successive portions or segments of material having a radial cross-section thinner than the radial cross-sections of the two successive portions or segments of material. The bridge or rib of material may in particular be arranged to connect two successive portions or segments of material, where the radial cross-section of the differentiated portion is smaller (by at least one dimension less than 0.1 mm) than the radial cross-section of the successive portions or segments of material adjacent to the differentiated portion.

[0013] It is also possible to provide other embodiments in which the radial cross section of the differentiating portion is larger (0.1 mm larger in at least one dimension) than the radial cross section of the continuous portion or segment of material adjacent to the differentiating portion. The differentiating portion may in particular include protruding appendages that increase its radial cross section.

[0014] It has been observed that the presence of a differentiated portion in the annular volume significantly reduces the risk of air pockets forming between the annular volume and the object onto which it is deposited, particularly when the annular volume is pressed against the object, for example to form a gasket.

[0015] In particular, the effect of expelling air has been confirmed when an annular quantity of material is deposited on the base of an object and inside the annular wall of the object, thereby reducing the risk of air pockets forming in the transition area between the base and the annular wall of the object, particularly when the annular quantity deposited on the object is pressed against the object (e.g., to form an annular gasket on the inside of a cap for closing a container).

[0016] It has been found that a certain effectiveness in evacuating air, such as reducing the risk of air pockets, can already be detected in distinct portions of the predetermined volume, each having a radial cross-section with at least one dimension (e.g., height or width) that differs by at least 0.1 millimeter from the radial cross-section of another portion of the annular predetermined volume (which may be less than or greater than that). [Brief explanation of the drawings]

[0017] The invention may be better understood and practiced with reference to the accompanying drawings, which show some non-limiting embodiments. [Figure 1] FIG. 1 is an exploded view of a coating device according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of the coating device of FIG. 1, cut along two cross-sectional planes perpendicular to each other. [Figure 3] FIG. 3 is a partial cross-sectional view of the coating device of FIG. 1 at vertical height. [Figure 4] FIG. 4 is a cross section taken along line IV-IV in FIG. [Figure 5] FIG. 5 shows, in partial cross-section in the vertical height direction, two operational steps of the coating device of FIG. 1: on the left, the shaping step where the annular quantity leaves the extruder, and on the right, the cutting and separation step where the annular quantity is cut. [Figure 6] FIG. 6 shows two operational steps of the application device of FIG. 5 in cross section generally in the vertical height direction. [Figure 7] FIG. 7 is a partial perspective view of a second embodiment of the applicator device according to the first embodiment, with some parts removed to better highlight other parts. [Figure 8] FIG. 8 is another view of the applicator device of FIG. 7, with some parts removed to better highlight other features. [Figure 9] FIG. 9 is a view of the applicator of FIG. 7 from yet another perspective, further emphasizing the separated annular portions. [Figure 10]FIG. 10 is a partial perspective view of a third embodiment of the coating device according to the present invention, cut along two cross-sectional planes that are orthogonal to each other. [Figure 11] FIG. 11 is a view of the applicator of FIG. 10 from another perspective, which better highlights the separated annular portions. [Figure 12] FIG. 12 is an exploded view of a fourth embodiment of the coating device according to the present invention. [Figure 13] FIG. 13 is an enlarged detail of FIG. [Figure 14] FIG. 14 is a cross section in the vertical height direction of the fifth embodiment of the coating device according to the first embodiment in an operation step in which the annular predetermined amount is separated. [Figure 15] FIG. 15 is an enlarged detail view of FIG. [Figure 16] FIG. 16 shows part of the cross section of FIG. 14 at an operating step when the annular volume has not yet been separated. [Figure 17] FIG. 17 is an enlarged detail of FIG. [Figure 18] FIG. 18 is a partial exploded view of a sixth embodiment of the coating device according to the present invention. [Figure 19] FIG. 19 is a vertical height section showing a detail of the application device of FIG. 18 in a working step in which the annular volume has not yet been separated. [Figure 20] FIG. 20 is a cross section of FIG. 19 at an actuation step where the annular predetermined amount is separated. [Figure 21] FIG. 21 is an exploded view in the vertical height direction of a seventh embodiment of the coating device according to the present invention. [Figure 22] FIG. 22 is an enlarged detail of FIG. [Figure 23] FIG. 23 is a vertical height section showing a detail of the application device of FIG. 21 in a working step in which the annular volume has not yet been separated. [Figure 24] FIG. 24 is a cross section of FIG. 23 at an actuation step where the annular predetermined amount is separated. [Figure 25]FIG. 25 is a partial exploded view showing an eighth embodiment of the coating device according to the present invention. [Figure 26] FIG. 26 is a vertical height section showing a detail of the application device of FIG. 25 in a working step in which the annular volume has not yet been separated. [Figure 27] FIG. 27 is a cross section of FIG. 26 at an actuation step where the annular predetermined amount is separated. [Figure 28] FIG. 28 is a perspective view showing the annular predetermined amount performed in the coating apparatus according to the present invention. [Figure 29] FIG. 29 is a cross section of a first cap for closing a container having an annular gasket made by molding an annular quantity applied with an application device according to the present invention. [Figure 30] FIG. 30 is an enlarged detail of FIG. [Figure 31] FIG. 31 is a cross section of a second cap for closing a container having an annular gasket made by molding an annular quantity applied with an application device according to the present invention. [Figure 32] FIG. 32 shows an enlarged detail of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] In the foregoing figures, similar elements in different embodiments are designated by the same reference numerals.

[0019] 1 generally denotes an application device that can be used in particular to apply a quantity D of sealing material to form an annular gasket on an object P. Application can be carried out in particular by separating an annular quantity D of material from a continuous flow of plasticized material (e.g., by extrusion) and applying the annular quantity D to a surface of the object P, for example the inside of a cap for closing a container.

[0020] The annular predetermined amount D may be applied to the inside of a closure cap (e.g., a metal or plastic cap). In other embodiments, the annular predetermined amount may be applied to a flat element (e.g., a disk), in particular made of metal or plastic, which may then be inserted in a more complex device to provide a sealing function.

[0021] The annular dose may also be applied (in particular with a sealing function) to, for example, a container or a cardboard element intended to form part of a container.

[0022] The annular predetermined amount can be applied directly to, for example, a plastic or metal container. In yet another embodiment, the annular predetermined amount can be inserted directly into a mold (e.g., an annular body) in order to obtain an object (e.g., an annular object), in particular with a closing function (e.g., a plug consisting of a plastic wall and a central metal disk with a gasket obtained from the annular predetermined amount) or with a function different from the closing function.

[0023] The application device 1 may in particular belong to a rotary application device (not shown) comprising a carousel which rotatably supports a number of application devices (e.g. identical to the application device 1) arranged angularly spaced from one another, and an extruder (e.g. of the screw type) which supplies the application devices with plasticized material. It is therefore also possible for the application device 1 to belong to a linear rather than rotary application machine.

[0024] The application device 1 may comprise or be operatively associated with compressive forming means for forming the annular predetermined quantity D after the predetermined quantity has been deposited on the object P. Such compressive forming means (not shown) may in particular be arranged on a carousel arranged downstream of the application device 1 for forming and applying the annular predetermined quantity D.

[0025] The application device 1 comprises a molten or plasticized material feeder 2. The feeder 2 may be connected to an extruder which may be configured to feed a plasticized sealing material suitable for forming a gasket, among other things.

[0026] Inside the feeder 2, at least one channel 3 may be received for feeding material to at least one material outlet 4 extending along a circumferential direction centered on the axis of the feeder 2 (e.g., a vertical axis taking into account the position of use of the application device 1).

[0027] The channel 3 may in particular have an annular portion for passing the plasticized material and may terminate in a material outlet 4. The annular portion of the channel 3 may communicate, for example in a derivative relationship, with a channel portion located upstream, for example a channel portion with a circular rectilinear cross section or a channel portion with another three-dimensional shape.

[0028] The material outlet 4 may be configured so that the exit direction of the annular flow of extruded plasticized material has at each exit point at least one normal component that is radial to the (vertical) axis of the feeder 2, and in particular at least one horizontal radial component.

[0029] The feeder 2 may in particular be provided with valve means for regulating the flow of the plasticized material. The feeder 2 may in particular be provided with heat regulation means (e.g. one or more resistors) for heating one or more parts in contact with the plasticized material.

[0030] The feeder 2 may in particular comprise an inner portion 5 and an outer portion 6 at least partially surrounding the inner portion 5. The outer portion 6 may in particular be bush-shaped. The channel 3 may in particular be defined between the inner portion 5 and the outer portion 6.

[0031] The application device 1 comprises a separator 7 which surrounds the feeder 2 and is configured to separate the annular quantity D of material from the material outlet 4. The separator 7 and the feeder 2 are movable coaxially with respect to each other (in particular along the axis of the feeder). In the particular embodiment illustrated herein, the separator 7 is movable in a (vertical) linear motion by a drive means, for example a drive means of known type.

[0032] The separator 7 may in particular have an annular cutting element which surrounds the feeder 2 and passes in front of the material outlet 4 in order to cut off the annular predetermined amount D in the step of separating the predetermined amount.

[0033] The separator 7 may be movable and have the possibility of adopting at least one pre-cutting position, in which it allows the plasticized material to exit the material outlet 4 and has the cutting edge of the annular cutting element ready to cut the material, and at least one post-cutting position, in which the cutting edge has already passed in front of the material outlet 4 and has already cut the material exiting the material outlet 4 to separate the annular predetermined amount D.

[0034] The drive means of the separator 7 may in particular be configured to perform cutting cycles by alternately, in particular reciprocating, the annular cutting element between a pre-cutting position and a post-cutting position to form at least one annular predetermined quantity D in each cycle.

[0035] The drive means may comprise, for example, cam means. The cam means may in particular have at least one (fixed) cam profile, for example a profile that extends substantially as an arc of a circumference coaxial with the rotation axis of the carousel. The cam means may in particular have at least one cam follower associated with the annular cutting element and coupled to said cam profile. The cam follower may for example comprise (roller) rolling means slidable on the cam profile.

[0036] The application device 1 may in particular have supply means (not shown) configured to supply the objects P. The supply means may in particular be configured to supply caps for closing the containers so that the annular dose D separated from the separator 7 can be deposited on the caps. The supply means may in particular be supply means of known type, such as, for example, a cap conveying line with at least one conveying carousel.

[0037] The supply means may in particular have at least one support for supporting the object P (in particular a support for supporting a cap for a container). The support may be movable so that the supported object P has the possibility to adopt a receiving position (e.g. an upper position) located in the vicinity of the material outlet 4 so that the just-formed annular predetermined amount D can contact and adhere to the surface (base B) of the supported object P. The support may also be able to adopt a removal position (e.g. a lower position) in which the supported object P is further away from the material outlet 4 so that the annular predetermined amount D that is more adherent to the surface of the object P can be peeled off from the separator 7.

[0038] Said surface of object P may be activated beforehand (by heating and / or by a layer of primer and / or by other adhesion promoting means) to facilitate this release.

[0039] The material outlet 4 comprises at least one differentiated outlet portion 8 arranged to generate a differentiated portion in the annular predetermined quantity D, as will be explained in more detail herein. The term "portion" of the annular predetermined quantity may particularly refer to an area arranged along the circumferential extent of the annular predetermined quantity D. This area (the length of which can be measured along the circumferential extent of the annular predetermined quantity D) may be filled with the material forming the predetermined quantity D, may be partially empty of material, or may be completely empty of material.

[0040] The differentiated outlet section 8 is defined by the fact that the radial cross section considered at the differentiated outlet section 8 is different from the radial cross section considered at the rest of the material outlet 4. Here, "radial" is understood to be relative to the axis along which the material outlet 4 extends in the circumferential direction. In the specific embodiment shown here, the axis of the material outlet 4 coincides with the (vertical) axis of the feeder 2 and the material feed channel 3 and / or with the corresponding (vertical) axis of movement between the feeder 2 and the separator 7.

[0041] The differentiated outlet section 8 may comprise, in particular, an outlet obstruction, which may be configured to form a localized blockage of the port along a circumferential extent of the material outlet 4 to prevent or restrict the passage of material, or an outlet enlargement, which may be configured to form a localized enlargement of the port along a circumferential extent of the material outlet 4 to allow a greater amount of material to pass through than surrounding port sections.

[0042] The application device 1 may in particular comprise two or more differentiated outlet sections 8 angularly spaced apart from one another and separated from one another by at least one succession of material outlets 4 .

[0043] The continuation of the material outlet 4 may in particular be a part of the material outlet 4 having a passage port of constant width. The width of said passage port considered as constant may in particular be a dimension parallel to the axis of the material outlet 4 or to the axis of the feeder 2. Said dimension of the passage port may in particular be the height (vertical dimension) of the passage port of the outlet material.

[0044] The application device 1 may in particular comprise three, or four, or five, or six differentiated outlet sections 8, which are angularly spaced apart from one another and separated by successive sections of the material outlets 4.

[0045] Each succession of material outlets 4 may in particular be a portion of material outlet 4 having a passage port of constant width.

[0046] The sum of the circumferential lengths SD of the differentiated outlet sections 8 may in particular be smaller than the sum of the circumferential lengths SC of the succession of material outlets 4. In particular, it is possible to provide that SD is < 0.75 x SC, or SD < 0.50 x SC, or SD < 0.25 x SC, or SD < 0.10 x SC. In the specific embodiment shown, the material outlets 4 comprise four differentiated outlet sections 8 angularly spaced apart (in particular equidistantly) from one another and arranged alternately with the four successions of material outlets 4, each succession of material outlets 4 extending over an angular length of approximately 80° along the circumferential direction and each differentiated outlet section 8 extending over an angular length of approximately 10° along the circumferential direction (so that SD = 0.125 x SC).

[0047] Each differentiated outlet section 8 may in particular extend in the circumferential direction by a length of less than 1 / 10 (corresponding to an angular range of less than 36°), or less than 1 / 20 (corresponding to an angle of less than 18°), or less than 1 / 30 (corresponding to an angle of less than 12°), or less than 1 / 60 (corresponding to an angle of less than 6°) of the total circumferential length of the material outlet 4 (i.e. the range of the circumference of the material outlet 4 corresponding to an angle of 360°).

[0048] The application device 1 may in particular comprise at least one cavity 9 obtained on the feeder 2 or on the separator 7 at the differentiated outlet 8. This cavity 9 may in particular be configured to be filled with the outlet material coming from the feed channel 3 inside the feeder 2. This cavity 9 may in particular be shaped and arranged in such a way that, at the differentiated portion 10 of the annular predetermined quantity D, it forms a bridge 11 of material that is continuous with the differentiated portion 10 and that connects the two portions of the annular predetermined quantity D located on two opposite sides thereof.

[0049] In some embodiments, the differentiated outlet portion 8 may comprise an outlet obstruction, in particular an obstruction integral with the feeder 2, and the cavity 9 may comprise a cavity formed on the outlet obstruction, the cavity 9 receiving the plasticized material allowing the formation of a bridge 11 of material joining the two portions of a continuous annular predetermined amount with the differentiated portion 10.

[0050] In some embodiments, the differentiated outlet portion 8 may in particular comprise an outlet blockage that is integral with the feeder 2, and the cavity 9 may comprise a groove obtained in the periphery of the feeder 2 (e.g. a periphery that is continuous with the outlet blockage), so that also in these embodiments the cavity 9 makes it possible to form a bridge 11 of material that is continuous with the differentiated portion 10 and that connects the two portions of a predetermined annular amount.

[0051] In some embodiments, the differentiated outlet section 8 may in particular constitute an outlet enlargement. The cavity 9 may in particular comprise a slit formed in the separator 7, for example a slit formed in an annular cutting element cutting an annular predetermined amount D, so that the cavity 9 formed in the separator 7 allows the formation of an appendage 12 protruding from a closed annular body of predetermined amount D (in particular a body having a constant radial cross section along the entire circumference).

[0052] In the embodiment of Figures 1-6, the material outlets 4 have four differentiated outlet sections 8 formed by four obstructions angularly spaced from one another and integral with the feeder 2 (in this embodiment, the obstructions are integral with the inner part 5), the differentiated outlet sections 8 alternating with four successive sections of material outlets 4 having a constant port width defined between the inner part 5 and the outer part 6 of the feeder 2. Each obstruction may in particular be made by a rib protruding from the inner part 5 and extending inside the feeder 2. The separator 7 comprises an annular cutting element having a continuous circular cutting edge.

[0053] In operation, the sealing material exits through the four successive portions of the material outlets 4 but cannot exit through the four outlet blockages. The separated annular predetermined quantity D then comprises four successive portions of material having a constant radial cross section, each of which extends a length along an arc of the circumference (in the form of a partial arc of a circle) and is spaced apart by four differentiating portions 10, each of which consists of an empty space, i.e., without sealing material, such that each successive portion of material of the annular predetermined quantity D is separated from the others by a respective empty space.

[0054] In the embodiment of Figures 7-9, material outlet 4 has four differentiated outlet sections 8 angularly spaced from one another, each of which may comprise an obturator integral with feeder 2 (e.g., integral with inner section 5). In this embodiment, each obturator has a cavity-shaped cavity 9 located between inner section 5 and outer section 6 of feeder 2, such that each obturator is dimensioned such that it does not occupy all of the space defined between the two sections of material outlet 4 located on opposite sides of differentiated outlet section 8. In this embodiment, each cavity 9 is located above a respective obturator.

[0055] During operation, the sealing material exits through the four successive portions of the material outlet 4 through four openings (in this embodiment, relatively thin openings) defined by four cavities 9 obtained as gaps between the inner portion 5 and the outer portion 6, but cannot exit through four obstructions positioned below the four openings.

[0056] The separated annular predetermined volume D then comprises four successive portions of material with a constant radial cross section, each extending a length along a circular arc of the circumference and sandwiched between four differentiated portions 10, each differentiated portion 10 comprising an empty space, i.e. a space without sealing material, and a bridge 11 of sealing material connecting two successive portions of material adjacent to each differentiated portion 10. In this embodiment, the bridge 11 of sealing material is arranged upwards, i.e. connecting the tops of the successive portions of the various materials.

[0057] The embodiment of Figures 10-11 differs from the embodiment of Figures 7-9 by the fact that each cavity 9 is arranged below a respective obstruction, and the separated annular predetermined volume D again has a constant radial cross section and comprises four continuous portions of material, each extending along a circumferential arc and interposed by four differentiated portions 10, each of which comprises a space free of sealing material and a bridge 11 of sealing material for connecting two continuous portions of material, which in this case are however arranged below, i.e. underneath, the various continuous portions of material.

[0058] The embodiment of Figures 12-13 differs from the embodiment of Figures 1-6 by the fact that each differentiated outlet 8 comprises an obstruction integral with the outer portion 6 rather than with the inner portion 5. The obstruction may be made of a rib projecting from the outer portion 6. Also in this case, the separated annular predetermined volume D comprises four successive portions of material having a constant radial cross section and extending in length along a circumferential arc, spaced apart by four differentiated portions 10 consisting of spaces free of sealing material separating the various successive portions of sealing material from one another.

[0059] In the embodiment of Figures 14 to 17, the material outlet 4 has four differentiated outlet sections 8 angularly spaced from one another. Each differentiated outlet section 8 is provided with an obstruction that is integral with the feeder 2, in this case with the outer part 6. The obstruction may be made of a rib protruding from the outer part 6.

[0060] Each differentiated outlet 8 comprises a cavity 9 arranged in a respective obturator. Each cavity 9 may, as in this embodiment, be arranged above a respective obturator (rib). Each cavity 9 may, as in this embodiment, comprise a groove formed on the outer part 6 (in particular on an obturator that is integral with the outer part 6). Each cavity 9 may, in particular, be obtained through removal of material of the outer part 6 by a machining operation.

[0061] During operation, the sealing material exits through the four successive portions of the material outlet 4, flows further through the four cavities 9 obtained as grooves in the outer portion 6, and exits through the four openings defined by the four cavities 9, but cannot exit at the four obstructions located below the four cavities.

[0062] The annular predetermined volume D separated from the separator 7 then comprises four successive portions of material having a constant radial cross section, each of which extends a length along a circumferential arc and is spaced apart by four differentiating portions 10, each of which comprises a void, i.e. a void space free of sealing material, and a bridge 11 of sealing material connecting the two successive portions of material that are contiguous with the respective differentiating portion 10. In this embodiment, the bridge 11 of sealing material is arranged upwards, i.e. connecting the tops of the successive portions of the various materials.

[0063] The embodiment of Figures 18 to 20 is similar to the embodiment of Figures 14 to 17, in that the four cavities 9 are obtained as grooves on the outer part 6. In this embodiment, the grooves are arranged differently than in the previous embodiments. In particular, in this embodiment, the cavities 9 (grooves) are arranged in the outer part 6 at a distance from the inner part 5, whereas in the previous embodiments they were arranged contiguous with the inner part 5. The separating annular predetermined volume D is also formed by four bridges 11, which in this case have a lower radial cross section than the radial cross sections of the four predetermined volume parts connected by the bridges.

[0064] The embodiment of Figures 21 to 24 differs from the embodiment of Figures 18 to 20 in that the cavities 9 are obtained not as grooves formed in an occlusion (rib) integral with the outer part 6, but as grooves formed in an occlusion (rib) integral with the inner part 5. Also, in this embodiment, the separated annular predetermined volume D comprises four bridges 11 arranged above it.

[0065] In the embodiment of Figures 25 to 27, the material outlet 4 has four differentiated outlet sections 8 formed by four cavities 9 angularly spaced from one another, each of which is obtained as a slit on the cutting edge of the separator 7, in particular on the annular cutting edge of an annular cutting element which separates a predetermined amount D from the rest of the plasticized sealing material.

[0066] In this case, the cavities 9 are arranged on the separator 7, while the material outlets 4 arranged on the feeder 2 have a continuous circumferential extent with constant passage ports (height) over the entire circumference. The cavities 9 (slits) on the separator 7 actually constitute an equal number of differentiated outlet sections 8 which result in outlet enlargements in the step of separating the annular predetermined volume D.

[0067] In fact, in this embodiment, each differentiated outlet section 8 is created indirectly by an interruption placed in the separator 7, rather than by an interruption placed directly at the material outlet 4 of the inner channel 3 of the feeder 2, as in the previous embodiment.

[0068] During operation, the sealing material exits through the material outlet 4, which in this case is formed by an outlet having constant passage ports over the entire circumferential extent of the material outlet 4, while a differentiated portion 10 of a predetermined amount D is formed by the effect of an interruption formed in the separator 7 and defined by a cavity 9 (in the form of a slit on the annular cutting element).

[0069] The various cavities (slits) cause a certain delay in the actual momentum of the cutting of the material relative to the rest of the cutting edge of the separator 7, resulting in a greater localized dispensing of the material leaving the channel 3 precisely at the cavity 9 and therefore in this case the formation of a differentiated portion 10 including an appendage 12.

[0070] The fact that the separator 7, instead of cavities 9 in the form of slits on the annular cutting element, comprises teeth protruding from the annular cutting element and causing a certain prediction of the actual momentum of the cutting of the material, makes it possible to provide embodiments (not shown) different from those of Figures 25 to 27, which cause a localized and expected interruption of the dispensing of the plasticized material from the channel 3, precisely at the part of the teeth, with respect to the rest of the cutting edge of the separator 7, resulting in the formation of differentiated parts, which in this case consist of parts with less material and therefore a lower radial cross-section than the radial cross-section of the adjacent parts.

[0071] In the embodiment disclosed herein, the material outlet 4 has four differentiated outlet sections 8 (particularly parts arranged angularly equidistant from one another) to form an equal number of differentiated portions 10 of the annular predetermined volume D. It is possible to provide embodiments in which the material outlet 4 has a different number N of differentiated outlet sections 8 (for example, 3 or 5 or 6, or 2≦N≦15, in particular 3≦N≦9) to form an equal number of differentiated portions 10 of the annular predetermined volume D.

[0072] The operation of the application device may in particular operate an application method that includes the step of feeding plasticized material, in particular a sealing material suitable for forming a gasket, through at least one channel 3 formed in the feeder 2 to at least one material outlet 4 extending circumferentially around the axis of the feeder 2.

[0073] The application method comprises the step of separating an annular predetermined quantity D of material from the material outlet 4 by a separator 7 which surrounds the feeder 2, the separator 7 and the feeder 2 moving coaxially with each other. The shear rate measured at the wall as the plastic flows in the channel 3 (commonly known as the shear rate γ) may be selected in particular in the range 2≦γ≦150 / s, more in particular 4≦γ≦80 / s.

[0074] The application method comprises the step of depositing an annular quantity D onto an object P, in particular onto a base B of the object P, which may for example be a cap for closing a container.

[0075] The separated annular predetermined quantity D includes at least one differentiating part 10, where the "differentiating part" is a part arranged along the circumferential range of the annular predetermined quantity D, and the radial cross-section of the annular predetermined quantity D is different from the radial cross-section considered in another part of the annular predetermined quantity D.

[0076] The term "radial direction" refers in this specification to the axis centered around which the annular predetermined quantity D extends in the circumferential direction. This axis may in particular coincide with the (vertical) axis of the feeder 2.

[0077] The separated annular predetermined quantity D may in particular consist of two or more differentiating parts 10 (in particular 4 or 5 differentiating parts 10, but different numbers N, for example 3, or 6, or 7 or more differentiating parts 10, or different numbers N of differentiating parts 10 with 2 ≤ N ≤ 15, in particular 3 ≤ N ≤ 9) that are angularly spaced from each other (in particular equidistantly) and separated from each other by at least one continuous part of the material forming the annular predetermined quantity D (in particular a part in which continuous parts and differentiating parts are mixed).

[0078] Each continuous part may in particular include a part of the material having a constant radial cross-section. Each continuous part may in particular include a part of the material shaped by extending in the form of an arc length having a circular cross-section. The continuous part may in particular be shaped as an arc having a circular cross-section of the same length. The differentiating part 10 may in particular extend longitudinally by the same circumferential length.

[0079] The total SD of the lengths of the differentiating parts 10 in the circumferential direction may in particular be less than or equal to half of the total SC of the lengths of the continuous parts (in the form of arcs of circular cross-section) in the circumferential direction. In particular, 0.25×SC ≤ SD < 0.05×SC may be possible. Each differentiating part 10 may in particular extend in the circumferential direction by less than 1 / 10, or less than 1 / 20, or less than 1 / 30, or less than 1 / 60 of the length of the annular predetermined quantity in the circumferential direction.

[0080] Each differentiated portion 10 may in particular consist of a cavity that is not occupied by material. Each differentiated portion 10 may in particular include a cavity that is not occupied by material. The radial cross section of the differentiated portion 10 may in particular be devoid of sealing material or have less sealing material than the radial cross section of another portion of the annular predetermined amount D.

[0081] Each cavity of the differentiated portion 10 may in particular be bounded between two end faces circumferentially opposite each other and arranged on two respective portions of the annular predetermined amount D. The two respective portions of the annular predetermined amount D may in particular be two portions extending in length along an axis shaped like circumferential arcs, i.e. two portions or segments of material in the form of arcs of circular cross section.

[0082] Each differentiating portion 10 may in particular comprise at least one bridge 11 of material connecting two portions of an annular predetermined volume D, in particular two portions extending over a length with a constant radial cross section.

[0083] The cutting frequency of the separator 7 may be selected according to the amount of material required to form the annular predetermined amount D. This amount may depend, inter alia, on the dimensions of the object P and / or the dimensions of the gasket G resulting from molding the predetermined amount D. For example, to form an annular gasket for a "press-on / twist-off" cap having a nominal diameter of 51 millimeters, it is possible to provide the annular predetermined amount D divided into four predetermined portions in the form of arcs of a circular crown separated by a differentiated portion of a predetermined amount of material, each of which weighs 0.25 grams, or 0.4 grams, or a weight value between 0.25 and 0.4 grams, or 0.3 grams, or 0.35 grams, or a weight value between 0.30 and 0.35 grams. According to another embodiment, to form an annular gasket on a "press-on / twist-off" type cap having a nominal diameter of 48 millimeters, the annular predetermined quantity D may be divided into three predetermined portions in the shape of a circular crown separated by a predetermined amount of differentiated material, each of which weighs 0.25 grams, or into four predetermined portions each having a weight value equal to 0.3 grams, or into five predetermined portions in the shape of a circular crown separated by a predetermined amount of differentiated material, each of which weighs 0.25 grams. As can be seen from these embodiments, the annular predetermined quantity D may have a different overall weight depending on the particular case. For example, it is also possible to vary the number of predetermined portions in each particular case by keeping the overall weight of the annular predetermined quantity D approximately constant.

[0084] The annular predetermined amount D is separated from the material outlet 4 by a separator 7 and deposited on the object P. It is also possible to provide a step (not shown) in which the annular predetermined amount D deposited on the object P is pressed (for example, by an annular compression punch) to form a gasket. In FIG. 29, an object P (in particular, a closure cap) is shown with an annular gasket G obtained by compression molding the annular predetermined amount D. In FIG. 30, G1 denotes the maximum radial dimension of the annular gasket G measured from the inner end to the outer end of the gasket, 2 denotes the annular recess of the maximum radial dimension present in the transition zone T of the object P (the cap) where there is a greater risk of undesirable air pockets forming between the gasket G and the object P, G3 denotes the maximum height of the gasket G, and W denotes the thickness of the cap, which includes both the thickness of the gasket G (measured at the outer sealing surface of the gasket G, which is pressed further downward in the molding step) and the thickness of the cap's sheet metal body.

[0085] The aforementioned thickness W may include, in particular, between 0.3 mm and 2 mm, more particularly between 0.55 mm and 1.6 mm, and even more particularly between 0.8 mm and 1.3 mm. Furthermore, in Figure 30, the dimensions (diameter or thickness) of the annular gasket G are shown merely as an example.

[0086] Referring to Figure 28, the length or maximum circumferential extent of the differentiated outlet section 8 (particularly the outlet obstruction) is indicated by L1, the length or maximum circumferential extent of the differentiated portion 10 of a predetermined amount D (particularly an empty portion with no material) is indicated by L2, the length or maximum circumferential extent of the continuous portion of a predetermined amount D (particularly having a constant overall radial cross-section) included between two differentiated portions 10 is indicated by L3, the maximum width or maximum radial extent of the overall radial cross-section of the continuous portion of a predetermined amount D is indicated by L4, and the height or maximum axial extent of the overall radial cross-section of the continuous portion of a predetermined amount D is indicated by L5.

[0087] Generally, it is confirmed that L1 and L2 are roughly equal, but depending on the process conditions and the rheological properties of the material, L1<L2またはL1> It may also be L2.

[0088] The relationship of L3 / L2 between the length L3 of the continuous part of the separated annular predetermined amount D and the length L2 of the differentiated part 10 of the separated annular predetermined amount D can be made to be between 2 and 20 (20 ≥ L3 / L2 ≥ 2), more particularly between 2.5 and 12 (12 ≥ L3 / L2 ≥ 2.5) by appropriate adjustment of the process of applying the predetermined amount D and / or appropriate sizing of the coating device 1. By selecting this relationship L3 / L2, the discharge of air can be promoted and the risk of generating bubbles or air pockets between the gasket G and the object P can be reduced.

[0089] The maximum radial dimension G1 of the annular gasket - which needs to be formed from the annular predetermined amount D - is larger than the maximum height G3 of the gasket (i.e., L4 ≥ L5 when G1 ≥ G3), but when G1 ≤ G3, L4 ≤ L5. In particular, it is possible to provide (by appropriate adjustment of the application process of the predetermined amount D and / or appropriate sizing of the coating device 1) that the width L4 of the continuous part of the separated annular predetermined amount D is larger than or the same as the height L5 of the continuous part of the predetermined amount. By selecting this relationship L4 / L5, the discharge of air is promoted and the risk of forming bubbles or air pockets between the gasket G and the object P is reduced.

[0090] In particular, it is possible to provide (by appropriate adjustment of the application process of the predetermined amount D and / or appropriate sizing of the coating device 1) that the width L4 of the continuous part of the separated annular predetermined amount D is substantially the same as the maximum radial dimension G2 of the annular recess existing in the transition zone T (i.e., L4 and G2 are substantially equal). It is particularly possible that G2 is slightly larger than L4, for example, 10% or less of L4, i.e., L4 < G2 ≤ 1.1 × L4.

[0091] Generally, by providing one or more differentiated parts 10, the risk of forming air pockets between the sealing material and the object P, which may be pressed when the annular predetermined amount D is deposited, is reduced.

[0092] The annular predetermined amount D may in particular be deposited on the inside of an annular wall S of the object P, which is connected to a base B of the object P by a transition zone T. The object P may in particular consist of a cap (for example a plastic cap, or a crown cap, or a metal cap, or even another type of cap) provided with a sealing device, for example a liner or a gasket. The sealing device is made of the aforementioned sealing material and may be molded from a single type of plastic, from a compound of different plastics, or have a multi-layer structure.

[0093] The annular predetermined quantity D can form a polymer gasket made in particular of low density polyethylene (LDPE), or linear low density polyethylene (LLDPE), or ultra-linear low density polyethylene (ULDPE), or a mixture of similar products, or ethylene vinyl acetate (EVA), or a compound based on polyvinyl chloride (PVC).

[0094] Alternatively, to create the annular predetermined amount D, it is also possible to use a sealing material containing a thermoplastic elastomer and its compounds, for example, a combination of a hard polymer and an elastomer, such as a combination of a polyolefin and a styrenic block copolymer, for example, a combination of polypropylene and ethylene propylene PP / EPR or a combination of polypropylene and ethylene propylene diene monomer PP / EPDM.

[0095] The density of the sealing material (polymer or mixture) used in particular to form the gasket may be comprised between 0.87 and 0.94 g / cm3, in particular between 0.88 and 0.92 g / cm3. The hardness of the sealing material (polymer or mixture) used in particular to form the gasket may be comprised between 40 and 90 Shore A, in particular between 55 and 85 Shore A.

Claims

1. feeding a material, in particular a sealing material suitable for forming a gasket, through at least one channel (3) formed in a feeder (2) to at least one material outlet (4) extending in a circumferential direction around the axis of said feeder (2); separating an annular quantity (D) of material from the material outlet (4) by a separator (7) surrounding the feeder (2), wherein the separator (7) and the feeder (2) move coaxially relative to each other; depositing said annular quantity (D) on an object (P), in particular on the base of a cap for closing a container; Including, A coating method in which the separated annular predetermined amount (D) comprises one or more differentiated portions (10), i.e., the radial cross-section of a differentiated portion (10) of the annular predetermined amount (D) is different from the radial cross-section of another portion of the annular predetermined amount (D), where "radial" is understood to refer to the axis about which the annular predetermined amount (D) extends circumferentially.

2. the separated annular predetermined quantity (D) comprises two or more differentiated portions (10) angularly spaced from one another and separated from one another by at least one continuous portion of the material of the annular predetermined quantity (D), in particular the number N of differentiated portions (10) is 2≦N≦15, more in particular 3≦N≦9, the separated annular predetermined quantity (D) in particular comprises three, or four, or five, or six differentiated portions (10), the differentiated portions (10) being angularly spaced from one another and interspersed with continuous portions of the material of the annular predetermined quantity (D); The method of claim 1.

3. each successive portion of material is shaped like an arc of a circular sector having an angular extent of more than 30°, or more than 45°, or more than 60°, each successive portion of material having in particular a constant radial cross section; The method of claim 2.

4. the sum of the lengths in the circumferential direction of the differentiated portions (10) SD is smaller than the sum of the lengths in the circumferential direction of the continuous portions SC, in particular SD<0.75 x SC, or SD<0.50 x SC, or SD<0.25 x SC, or SD<0.10 x SC; The method according to claim 2 or 3.

5. each differentiated portion (10) extends in the circumferential direction by less than 1 / 10, or less than 1 / 20, or less than 1 / 30, or less than 1 / 60 of the circumferential length of said annular predetermined amount (D); 10. A method according to any one of the preceding claims.

6. each differentiated portion (10) consists of or includes a cavity not occupied by material, whereby a radial cross section at said differentiated portion (10) is free of material or has less material than a radial cross section at another portion of said annular volume (D); 10. A method according to any one of the preceding claims.

7. each cavity is bounded by two end faces circumferentially opposite each other and arranged in two respective portions of said annular volume (D), said two respective portions of said annular volume (D) being in particular two portions extending in length along an axis shaped like a circumferential arc; The method of claim 6.

8. Each differentiating portion (10) comprises at least one bridge (11) of material connecting two portions of said annular volume (D) located on either side of said differentiating portion (10), The method of claim 7.

9. The annular quantity (D) is deposited on the inside of the annular wall (S) of the object, which is connected to the base (B) of the object by a transition zone (T), 10. A method according to any one of the preceding claims.

10. An application device, in particular for carrying out the method according to any one of claims 1 to 9, comprising: a feeder (2) in particular connected to an extruder for sealing material suitable for forming gaskets, which feeds at least one channel (3) for feeding material, in particular plasticized material, to at least one material outlet (4) extending in a circumferential direction around the axis of said feeder (2); a separator (7) surrounding the feeder (2) and configured to separate an annular quantity (D) of material from the material outlet (4), the separator (7) and the feeder (2) being coaxially movable relative to each other, the annular quantity (D) being intended to be deposited on an object (P), in particular a cap for closing a container, to form a gasket; Equipped with The material outlet (4) comprises at least one differentiated outlet section (8) arranged to generate a differentiated portion (10) within the annular volume (D), the radial cross section at the differentiated outlet section (8) being different from the radial cross section at other parts of the material outlet (4), where "radial" is understood to refer to an axis about which the material outlet (4) extends in a circumferential direction, the differentiated outlet section (8) comprising in particular an outlet closure section or an outlet widening section.

11. the device comprises two or more differentiated outlets (8) angularly spaced from one another and separated from one another by at least one succession of the material outlets (4), the device in particular comprising a number N of differentiated outlets (8) such that 2≦N≦15, more in particular 3≦N≦9, the device in particular comprising three, or four, or five, or six differentiated outlets (8), the differentiated outlets (8) angularly spaced from one another and separated from one another by successions of the material outlets (4), each succession of the material outlets (4) in particular having a constant passage port, 11. The apparatus of claim 10.

12. each succession of said material outlets (4) extends along a circumferential arc having an angular extent of greater than 30°, or greater than 45°, or greater than 60°; 12. The apparatus of claim 11.

13. the sum of the lengths SD of the differentiated outlet sections (8) of the material outlets (4) in the circumferential direction is smaller than the sum of the lengths SC of the successive sections of the material outlets (4) in the circumferential direction, in particular SD<0.75 x SC, or SD<0.50 x SC, or SD<0.25 x SC, or SD<0.10 x SC; 13. Apparatus according to claim 11 or 12.

14. each differentiated outlet section (8) of the material outlet (4) extends in the circumferential direction by less than 1 / 10, or less than 1 / 20, or less than 1 / 30, or less than 1 / 60 of the total circumferential length of the material outlet (4); 14. Apparatus according to any one of claims 10 to 13.

15. the differentiated outlet (8) comprises at least one cavity (9) obtained on the feeder (2) for forming, in the differentiated portion (10) of the annular volume (D), a bridge (11) of material connecting two portions of the annular volume (D), 15. Apparatus according to any one of claims 10 to 14.

16. The differentiated outlet section (8) comprises an outlet blockage integral with the feeder (2), and the cavity (9) comprises a gap formed in the feeder (2) or a groove obtained in the outlet blockage.

16. The apparatus of claim 15.

17. the differentiated outlet (8) comprises at least one cavity (9) in the form of a slit obtained on the annular cutting element of the separator (7) for forming an appendage (12) of material protruding from the annular volume (D); 17. Apparatus according to any one of claims 10 to 16.

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