Method and apparatus for applying dose of material

Abstract

A method and apparatus for applying a dose of sealing material to a closed lid of a container to form a gasket, wherein an annular dose is separated from a flow of plasticized material and deposited on a substrate of the lid; the plasticized material is fed via a channel until it reaches a material outlet extending in a circumferential direction; the annular dose comprises at least one separating portion, whereby a radial cross-section of the separating portion of the annular dose is different from a radial cross-section of another portion of the annular dose, where "radial" is understood as an axis around which the annular dose extends in a circumferential direction; the presence of a partition portion reduces the risk of forming a cavitation between the sealing material and the cap.

Description

Background Art

[0001] The present invention relates to a method and an apparatus for applying a dose of material, such as a sealing material, in particular by separating the dose of material from a continuous plasticized material flow by extrusion and applying the separated dose to the surface of an object, such as the inside of a lid for closing a container.

[0002] In particular, but not exclusively, the invention can be used to apply an annular dose of material, in particular a sealing material, to a surface, for example to form an annular gasket on an object, for example to the inside of a lid (made of metal or plastic) for closing a container; or to apply an annular dose of material to a flat element, in particular made of metal or plastic, such as a disc, which can then be inserted into a more complex device with a sealing function; or to apply an annular dose of material, in particular having a sealing function, to a cardboard element intended, for example, to form a container or part of a container, or directly to a container, for example made of plastic or metal; or to insert an annular dose of material directly into a mold in order to obtain therefrom an object, for example an annular object, which in particular has a closing function (for example a plug composed of a wall made of plastic and a central metal disc provided with a gasket obtained from the annular dose) or also has another function different from the closing function.

[0003] Patent publications JP H06-312762A, US2012 / 0171381 A1, US2017 / 0239848 A1 and US2020 / 0376724 A1 each show an application method in the preamble of claim 1, wherein the radial cross section of the separated annular dose is constant over the entire circumference of the dose.

[0004] One of the problems of the prior art is to apply an annular dose of material (in particular, a sealing material suitable for forming a gasket) to an object, in particular to the base of an object (for example a lid for closing a container) and inside the annular wall of the object, without forming air pockets between the annular dose of material and the object, in particular in the transition area between the base and the annular wall of the object. Summary of the invention

[0005] An object of the present invention is to propose a method and / or device capable of solving the aforementioned problems of the prior art.

[0006] It is an object of the present invention to provide an application method and / or an application device which is an alternative to the prior art application methods and / or application devices.

[0007] One advantage is to provide an apparatus which is simple and inexpensive in construction for applying an annular dose of material to a surface of an article, particularly to form a gasket in a closure cap.

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

[0009] These objects and advantages and yet other objects and advantages are achieved by methods and / or apparatus according to one or more of the claims set forth below.

[0010] In one specific example, a method for applying an annular dose of sealing material, in particular for applying an annular dose of sealing material to the inside of a closure lid of a container to form a gasket, comprises the steps of separating the annular dose from a flow of plasticized material and depositing the annular dose on an object, wherein the plasticized material is fed through a channel until it reaches a material outlet extending in a circumferential direction, and wherein the separated annular dose comprises at least one partition portion, wherein the partition portion is understood to mean a partition portion having a radial cross-section that is different from a radial cross-section of another portion of the annular dose, wherein "radial" is understood to mean the axis around which the annular dose extends in the circumferential direction.

[0011] The separated annular dose may in particular comprise several continuous portions or segments of material (e.g. three, or four, or five, or six continuous portions or segments of material), each of which extends along a circumferential arc (e.g. portions or segments of material each in the shape of a circular crown arc), interspersed with the same number of partitions, each of which comprises a cavity free of material, which cavity is arranged in the space comprised between two continuous portions or segments of material. Each continuous portion or segment of material may be shaped as a circular sector arc having an angular extent of greater than 30°, or greater than 45°, or greater than 60°. The continuous portion or segment of material may have a constant radial cross section over its entire length or circumference.

[0012] Each cavity of a respective separating portion may occupy all the space contained between two consecutive portions or segments of material, so that there is an empty space completely devoid of material between two consecutive portions or segments of material, or there may be a bridge or rib of material between two consecutive portions or segments of material having a radial cross-section thinner than the radial cross-section of the two consecutive portions or segments of material. The bridge or rib of material may in particular be configured to connect two consecutive portions or segments of material together. In this case, the radial cross-section of the separating portion is smaller (at least one dimension is smaller than 0.1 mm) than the radial cross-section of the continuous portion or segment of material adjacent to the separating portion.

[0013] It is possible to provide other embodiments in which the radial cross section of the separating portion is larger (at least one dimension exceeds 0.1 mm) than the radial cross section of the continuous portion or segment of material adjacent to the separating portion. The separating portion may in particular comprise a protruding appendage increasing its radial cross section.

[0014] It has been observed that the presence of the separating portion in the ring-shaped dose significantly reduces the risk of air pockets forming between the ring-shaped dose and the object on which it has been deposited, in particular when the ring-shaped dose is pressed against the object, for example to form a gasket.

[0015] In particular, when an annular dose of material is deposited on the base of an object and inside the annular wall of the object, the effect of evacuating air has been determined and the risk of forming air pockets in the transition area between the base and the annular wall of the object has been reduced, especially when the annular dose deposited on the object is pressed against the object, for example to form an annular gasket inside a lid for closing a container.

[0016] It has been found that a certain effectiveness in evacuating air (which results in a reduced risk of cavitation) may have been detected by means of partitioned portions of the dose, each of which has a radial cross-section having at least one dimension (e.g. height or width) that differs (is smaller or possibly larger) from the radial cross-section of another portion of the annular dose by at least 0.1 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features and features of the invention will be more clearly described with the aid of the accompanying drawings which show some specific embodiments of the invention by way of non-limiting example, in which:

[0018] Figure 1 is an exploded view of a first embodiment of an application device according to the first embodiment;

[0019] Figure 2 for Figure 1 A perspective view of an application device in which two cross-sectional planes are orthogonal to each other;

[0020] Figure 3 for Figure 1 A partial cross-sectional view of a vertical elevation view of an application device;

[0021] Figure 4 for Figure 3 Section IV-IV;

[0022] Figure 5 Shown in partial cross-section in vertical elevation Figure 1 Two operating steps of an application device, wherein on the left, the annular dose is in a forming step leaving the extruder, and on the right, the annular dose is in a cutting and separation step;

[0023] Figure 6 Shown in full cross-section vertical elevation Figure 5 Two operating steps of the application device;

[0024] Figure 7is a partial perspective view of a second embodiment of an application apparatus according to the first embodiment, with some parts removed to better emphasize other parts;

[0025] Figure 8 for Figure 7 a view of the application device from another perspective with some parts removed to better emphasize other parts;

[0026] Fig. 9 for Figure 7 A view of the application device of from yet another perspective, wherein the separated annular doses are better emphasized;

[0027] Fig.10 A partial perspective view of a third specific example of an application apparatus according to the present invention, in which two cross-sectional planes are orthogonal to each other;

[0028] Fig.11 for Fig.10 A view of the application device from another perspective, in which the separated annular doses are better emphasized;

[0029] Fig.12 is an exploded view of a fourth specific example of an application device according to the present invention;

[0030] Fig.13 for Fig.12 Magnified details of

[0031] Fig.14 is a section in a vertical elevation view of a fifth embodiment of the application device according to the first embodiment in an operating step in which the annular dose has been separated;

[0032] Fig.15 for Fig.14 Magnified details of

[0033] Fig.16 Shown in the operating steps where the ring dose has not yet been separated, Fig.14 a portion of a cross section;

[0034] Fig.17 for Fig.16 Magnified details of

[0035] Fig.18 An exploded partial view of a sixth specific example of an application device according to the present invention;

[0036] Fig.19 For the operation steps in which the annular dose has not yet been separated, Fig.18 A cross section in a vertical elevation view of a detail of an application device;

[0037] Fig. 20 For the operation step in which the annular dose has been separated, Fig.19 The cross section of

[0038] Fig.21 is an exploded view in vertical elevation of a seventh embodiment of an application apparatus according to the present invention;

[0039] Fig. 22 for Fig.21 Magnified details of

[0040] Fig.23 For the operation steps in which the annular dose has not yet been separated, Fig.21 A cross section in a vertical elevation view of a detail of an application device;

[0041] Fig.24 For the operation step in which the annular dose has been separated, Fig.23 The cross section of

[0042] Fig.25 is a partial perspective view of an eighth specific example of an application device according to the present invention;

[0043] Fig.26 For the operation steps in which the annular dose has not yet been separated, Fig.25 A cross section in a vertical elevation view of a detail of an application device;

[0044] Fig. 27 For the operation step in which the annular dose has been separated, Fig.26 The cross section of

[0045] Fig.28 A perspective view showing an annular dose produced by means of an application device according to the invention;

[0046] Fig.29 a section or a first cover for closing a container with an annular gasket made by moulding an annular dose applied by means of an application device according to the invention;

[0047] Fig.30 exhibit Fig.29 Magnified details of

[0048] Fig.31 a section of a second cover for closing a container with an annular gasket made by moulding an annular dose applied by means of an application device according to the invention;

[0049] Fig.32 exhibit Fig.31 Zoomed in details. DETAILED DESCRIPTION

[0050] In the aforementioned figures, similar elements of different embodiments have been indicated by the same numerals.

[0051] 1 generally indicates an application device which can be used in particular for applying a dose D of sealing material for forming an annular gasket on an object P. The application can be carried out in particular by separating an annular dose D of material from a continuous plasticized material flow (for example by extrusion) and applying the annular dose D to a surface of an object P, for example to the inside of a cap for closing a container.

[0052] The annular dose D can be applied inside a closure cap, such as a cap made of metal or plastic. In other embodiments, the annular dose can be applied to a flat element, such as a disk, especially made of metal or plastic, which can then be inserted into a more complex device with a sealing function.

[0053] It is also possible to apply an annular dose, in particular having a sealing function, to a cardboard element which is intended, for example, to form a container or a part of a container.

[0054] The annular dose can be applied directly to a container, for example made of plastic or metal. In yet other embodiments, the annular dose can be inserted directly into a mold to obtain an object thereof (for example an annular object) which has in particular a closing function (for example a plug consisting of a wall made of plastic and a central metal disk provided with a gasket obtained from the annular dose) or also has a function different from the closing function.

[0055] The application device 1 may in particular be a rotary application machine (not shown) comprising a rotating rack which rotatably supports a plurality of application devices (e.g. identical to the application device 1) arranged angularly spaced from one another and an extruder (e.g. a screw extruder) which feeds the plasticized material to the application devices. Thus, the application device 1 may be a linear rather than a rotary application machine.

[0056] The application device 1 may comprise, or may be operatively associated with (e.g. connected to a processing line) a compression-forming member for forming the annular dose D after the dose has been deposited on the object P. This compression-forming member (not shown in the figures) may be arranged in particular on a carousel downstream of the application device 1, so as to form and apply the annular dose D.

[0057] The application device 1 comprises a feeder 2 of molten or plasticized material. The feeder 2 may in particular be connected to an extruder which may be arranged to feed plasticized sealing material suitable for forming a gasket.

[0058] Inside the feeder 2, at least one channel 3 may be housed to feed material to at least one material outlet 4 extending in a circumferential direction around an axis of the feeder 2 (eg a vertical axis considering the position of use of the application device 1).

[0059] The channel 3 may in particular comprise an annular portion for passing plasticized material which 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 straight cross section having a circular shape or a portion of a channel having another solid shape.

[0060] The material outlet 4 may be arranged such that the outlet direction of the annular flow of the extruded plasticized material has at each outlet point at least one normal component radial to the (vertical) axis of the feeder 2, in particular at least one horizontal radial component.

[0061] The feeder 2 may in particular comprise valve means for regulating the flow of the plasticized material. The feeder 2 may in particular comprise heat regulating means (eg one or more resistors) for heating one or more parts in contact with the plasticized material.

[0062] The feeder 2 can in particular comprise an inner part 5 and an outer part 6 at least partially surrounding the inner part 5. The outer part 6 can in particular be sleeve-shaped. The channel 3 can in particular be defined between the inner part 5 and the outer part 6.

[0063] The application device 1 comprises a separator 7 which surrounds the feeder 2 and is arranged to separate annular doses D of material from the material outlet 4. The separator 7 and the feeder 2 are movable coaxially relative to each other (in particular along the axis of the feeder). In the specific embodiment described here, the separator 7 is movable in a (vertical) linear motion by means of a drive member (for example a drive member of a known type).

[0064] The separator 7 may in particular comprise an annular cutting element which surrounds the feeder 2 and which, during the step of separating the annular doses D, passes in front of the material outlet 4 to cut the doses.

[0065] The separator 7 may be movable, possibly adopting: at least one front cutting position, in which the separator 7 enables the plasticized material to leave the material outlet 4 and in which it has a blade of an annular cutting element ready to cut the material; and at least one rear cutting position, in which the blade has passed in front of the material outlet 4 and has cut the material that has left the material outlet 4 to separate the annular dose D.

[0066] The drive means of the separator 7 may in particular be arranged to move the annular cutting element alternately, in particular to and fro between a front cutting position and a rear cutting position, to perform cutting cycles so as to form at least one annular dose D in each cycle.

[0067] The drive member may comprise, for example, a cam member. The cam member may in particular comprise at least one (fixed) cam profile, for example a profile extending substantially as a circumferential arc coaxial with the axis of rotation of the carousel. The cam member may in particular comprise at least one cam follower associated with the annular cutting element and coupled to the aforementioned cam profile. The cam follower may comprise, for example, a (roller) rolling member that can slide on the cam profile.

[0068] The application device 1 may in particular comprise a feeding member (not shown in the figures) arranged to feed the objects P. The feeding member may in particular be arranged to feed caps for closing containers, so that the annular doses D separated from the separator 7 can be deposited on the caps. The feeding member may in particular be a feeding member of known type, such as, for example, a cap conveying line comprising at least one conveying carousel.

[0069] The feeding means may in particular comprise at least one support for supporting the object P (in particular, a support for supporting the lid of the container). The support may be movable, possibly adopting a receiving position (for example an upper position) in which the supported object P is close to the material outlet 4, so that the annular dose D just formed is in contact with the surface (substrate B) of the supported object P and can adhere to this surface. The support may be able to adopt a removal position (for example a lower position) in which the supported object P is away from the material outlet 4, so that the annular dose D more adhered to the surface of the object P is peeled off from the separator 7.

[0070] The aforementioned surface of the object P may be pre-activated (by heating and / or by a primer layer and / or by other adhesion promoting means) to facilitate this peeling.

[0071] The material outlet 4 comprises at least one separated outlet portion 8 configured to produce a separated portion in the annular dose D, as will be better explained further in the description. The term "portion" of an annular dose may particularly mean an area arranged along the circumferential extent of the annular dose D. This area (whose length may be measured along the circumferential extent of the annular dose D) may be filled with the material forming the dose D, or may be partially free of material, or may be completely free of material.

[0072] The separated outlet portion 8 is defined by the fact that the radial cross section considered in the separated outlet portion 8 is different from the radial cross section considered in the other part of the material outlet 4, wherein "radial" is understood to mean the axis about which the material outlet 4 extends in the circumferential direction. In the specific embodiment described 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.

[0073] The separated outlet portion 8 may in particular include: an outlet blocking portion, which may be arranged to form a local blockage of the port along the circumferential range of the material outlet 4 so as to prevent or restrict the passage of material; or include: an outlet expansion portion, which may be arranged to form a local widening of the port along the circumferential range of the material outlet 4 so as to enable a larger amount of material to pass through rather than reaching the surrounding port portion.

[0074] The application device 1 may in particular comprise two or more separated outlet portions 8 which are angularly spaced apart from one another and separated from one another by at least one continuous portion of the material outlet 4 .

[0075] The continuous part of the material outlet 4 may in particular be a part of the material outlet 4 having a channel port of constant width. The aforementioned width of the channel port regarded as constant may in particular be a dimension parallel to the axis of the material outlet 4 or the axis of the feeder 2. The aforementioned dimension of the channel port may in particular be the height (vertical dimension) of the channel port from which the material is discharged.

[0076] The application device 1 may in particular comprise three, or four, or five, or six separated outlet portions 8 which are angularly spaced apart from one another and are spaced apart by a continuous portion of the material outlet 4 .

[0077] The respective continuous sections of the material outlet 4 can in particular be sections of the material outlet 4 having a passage port of constant width.

[0078] The sum SD of the lengths of the separated outlet portions 8 in the circumferential direction may in particular be smaller than the sum SC of the lengths of the consecutive portions of the material outlet 4 in the circumferential direction. In particular, it is possible to provide for SD<0.75*SC, or SD<0.50*SC, or SD<0.25*SC, or SD<0.10*SC. In the illustrated particular embodiment, the material outlet 4 comprises four separated outlet portions 8 which are angularly (in particular, equidistantly) spaced apart from one another and which alternate with four consecutive portions of the material outlet 4, wherein each consecutive portion of the material outlet 4 extends over an angle of about 80° in length along the circumferential extent, and each separated outlet portion 8 extends over an angle of about 10° in length along the circumferential extent (so that SD=0.125*SC).

[0079] The length of each separated outlet portion 8 extending in the circumferential direction may in particular be less than 1 / 10 (corresponding to an angular range less than 36°), or less than 1 / 20 (corresponding to an angular range less than 18°), or less than 1 / 30 (corresponding to an angular range less than 12°), or less than 1 / 60 (corresponding to an angular range less than 6°) of the total length of the material outlet 4 in the circumferential direction (that is, the circumferential range of the material outlet 4, which corresponds to an angular range equal to 360°).

[0080] The application device 1 may comprise in particular at least one cavity 9 obtained on the feeder 2 or separator 7 at the separated outlet portion 8. This cavity 9 may in particular be arranged to be filled with discharged material leaving the feed channel 3 inside the feeder 2. This cavity 9 may in particular be shaped and configured to form a bridge 11 of material at the separated portion 10 of the annular dose D, which joins two portions of the annular dose D connected to the separated portion 10 and located on two opposite sides of the annular dose.

[0081] In some specific examples, the separated outlet portion 8 may in particular include an outlet blocking portion integral with the feeder 2, and the cavity 9 may include a cavity formed on the outlet blocking portion, so that the cavity 9 for receiving the plasticized material enables the formation of a bridge portion 11 of the material, connecting the two parts of the annular dose connected to the separating portion 10.

[0082] In some specific examples, the separating outlet portion 8 may in particular include an outlet blocking portion integral with the feeder 2, and the cavity 9 may include a groove obtained on the circumference of the feeder 2 (for example, the circumference connected to the outlet blocking portion), so the cavity 9 also enables the formation of a bridge portion 11 of material in these specific examples, connecting the two parts of the annular dose connected to the separating portion 10.

[0083] In some embodiments, the separated outlet portion 8 may in particular comprise an outlet expansion. The cavity 9 may in particular comprise a slit formed on the separator 7 (e.g. on an annular cutting element cutting the annular dose D), so that the cavity 9 formed on the separator 7 enables the formation of an appendage 12 protruding from the closed annular body of the dose D (in particular, a body having a constant radial cross section along the entire circumference).

[0084] exist Figures 1 to 6 In the embodiment of the invention, the material outlet 4 has four separated outlet sections 8 formed by four plugging parts, which are angularly spaced from each other and are integral with the feeder 2 (in this embodiment, the plugging parts are integral with the inner part 5), alternating with four continuous parts of the material outlet 4, which have a constant port width defined between the inner part 5 and the outer part 6 of the feeder 2. Each plugging part can be made in particular by a rib-like part protruding from the inner part 5 and extending inside the feeder 2. The separator 7 comprises an annular cutting element with a continuous circular blade.

[0085] In operation, the sealing material will exit through four consecutive portions of the material outlet 4, while it will not be able to exit the four outlet obstructions. After separation, the annular dose D will contain four consecutive portions of material with a constant radial cross-section, each of which will extend in length along a circumferential arc (in the form of a circular sector arc), separated by four partitions 10, each of which will consist of an empty space, i.e. without sealing material, so that each consecutive portion of the material of the annular dose D will be separated from another portion by a respective empty space.

[0086] exist Figures 7 to 9 In the specific example of the material outlet 4, the material outlet 4 has four separated outlet parts 8 arranged at an angle to each other, each of which includes a blocking portion that is integral with the feeder 2 (for example, integral with the inner part 5). In this specific example, each blocking portion has a size such as not to occupy all the space included between two parts of the material outlet 4 arranged on opposite sides of the separated outlet parts 8, because at each blocking portion, there is a cavity 9 in the shape of a cavity arranged between the inner part 5 and the outer part 6 of the feeder 2. In this specific example, each cavity 9 is arranged above a respective blocking portion.

[0087] In operation, the sealing material will leave through four continuous parts of the material outlet 4 and through four openings (in this specific example, relatively thin openings) defined by four cavities 9 obtained as gaps between the inner part 5 and the outer part 6, and it will not be able to leave at the four blockages arranged below the four openings.

[0088] The annular dose D after separation will comprise four continuous portions of material of constant radial cross-section, each of which will extend in length along a circumferential arc, interspersed with four separation portions 10, each of which will comprise an empty space, i.e. without sealing material, and a bridge 11 of sealing material which will join two continuous portions of material connected to a respective separation portion 10. In this embodiment, the bridge 11 of sealing material is arranged at the upper, i.e. upper part, for joining the various continuous portions of material.

[0089] Figure 10 to Figure 11 The specific instance of Figures 7 to 9 A specific example: each cavity 9 is arranged below a respective blocking portion, so that in this case as well, the separated annular dose D will include four continuous portions of material with a constant radial cross-section, each continuous portion extending along a circumferential arc, interspersed with four partition portions 10, each containing a space without sealing material; and a bridging portion 11 of sealing material for joining two continuous portions of material, wherein, however, the bridging portion 11 of sealing material is arranged below, i.e., the lower portion for joining the various continuous portions of material.

[0090] Figure 12 to Figure 13 The specific instance of Figures 1 to 6 Specific example: each separated outlet portion 8 comprises a plugging portion integral with the outer portion 6 and not with the inner portion 5. The plugging portion may be made of a rib-like portion protruding from the outer portion 6. In this case too, the separated annular dose D will comprise four consecutive portions of material of constant radial cross-section, extending in length along a circumferential arc, separated by four separation portions 10 consisting of spaces free of sealing material, which separate the various consecutive portions of sealing material from each other.

[0091] exist Figures 14 to 17 In the specific example of , the material outlet 4 has four divided outlet parts 8 arranged angularly spaced from each other. Each divided outlet part 8 comprises a plugging part integral with the feeder 2, in this case integral with the outer part 6. The plugging part can be made of a rib-like part protruding from the outer part 6.

[0092] Each separated outlet portion 8 comprises a cavity 9 arranged at the respective blocking portion. In this embodiment, each cavity 9 can be arranged above the respective blocking portion (rib-shaped portion). In this embodiment, each cavity 9 can comprise a groove formed on the outer portion 6 (in particular, on the blocking portion integral with the outer portion 6). Each cavity 9 can be obtained in particular by a mechanical working task by removing material of the outer portion 6.

[0093] In operation, the sealing material will leave through four consecutive parts of the material outlet 4, and will further flow through the four cavities 9 obtained by the grooves on the outer part 6, and will then leave through the four openings defined by the four cavities 9, without being able to leave at the four blockages arranged below the four cavities.

[0094] The annular dose D separated from the separator 7 will then comprise four consecutive portions of material of constant radial cross-section, each of which will extend in length along a circumferential arc, separated by four partitions 10, each of which will comprise an empty space, i.e. no sealing material, and a bridge 11 of sealing material that will join two consecutive portions of material connected to a respective partition 10. In this particular example, the bridge 11 of sealing material is arranged at the upper, i.e. upper part, for joining the various consecutive portions of material.

[0095] Figures 18 to 20 A specific example is similar to Figures 14 to 17, in which the four cavities 9 are obtained as grooves on the outer part 6. In this embodiment, the grooves are arranged in a different way from the previous embodiments. In particular, in this embodiment, the cavities 9 (grooves) are arranged on the outer part 6 at a distance from the inner part 5, while in the previous embodiments they were arranged continuously with the inner part 5. The separated annular dose D is also formed in this case by four bridges 11, the radial cross section of which is lower than the radial cross section of the four dose parts joined by the bridges.

[0096] Figure 21 to Figure 24 The specific instance of Figures 18 to 20 : the cavity 9 is obtained as a groove formed on a plug (rib) integral with the inner part 5, and not as a groove formed on a plug (rib) integral with the outer part 6. Also in this embodiment, the separated annular dose D comprises four bridges 11 arranged on the top.

[0097] exist Figure 25 to Figure 27 In the specific example of , the material outlet 4 has four separated outlet portions 8 formed by four cavities 9 arranged at an angle to each other, each of which is obtained as a slit on the blade of a separator 7, in particular a slit on the annular blade of an annular cutting element that separates the dose D from the rest of the plasticized sealing material.

[0098] In this case, the cavity 9 is arranged on the separator 7, while the material outlet 4 arranged on the feeder 2 has a circumferential extent connected to a passage port (height) that is constant over the entire circumference. The cavity 9 (slit) on the separator 7 actually constitutes the same number of divided outlet portions 8, which causes the outlet to expand during the step of separating the annular dose D.

[0099] In practice, in this embodiment, each separated outlet portion 8 is indirectly formed by a discontinuity arranged on the separator 7, rather than being formed by a discontinuity directly arranged on the material outlet 4 of the channel 3 inside the feeder 2 as in the prior art embodiment.

[0100] In operation, the sealing material will leave via the material outlet 4, which in this case is formed via an outlet having a constant channel port over the entire circumferential extent of the material outlet 4, while the separated portion 10 of the dose D is formed via the effect of an interruption formed on the separator 7 and defined by the cavity 9 (in the form of a slit on the annular cutting element).

[0101] The various cavities (slits) cause a certain delay in the actual momentum of material cutting relative to the rest of the blade of the separator 7, thereby causing a greater local distribution of the discharged material from the channel 3 at this cavity 9 and therefore causing the formation of a partition 10, which in this case includes an appendage 12.

[0102] It is possible to provide a different Figure 25 to Figure 27 A (non-illustrative) specific example of a specific example: the separator 7 comprises a tooth instead of a cavity 9 in the form of a slit on an annular cutting element, which tooth protrudes from the annular cutting element and causes a certain anticipation of the actual momentum of the material cutting relative to the rest of the blade of the separator 7, thereby causing a local expected interruption of the distribution of the plasticized discharge material from the channel 3 at this tooth and thus causing the formation of a separation portion, which in this case consists of a portion with less material and therefore a radial cross-section lower than the radial cross-section of the adjacent portion.

[0103] In the embodiment disclosed here, the material outlet 4 has four divided outlet portions 8 (specifically, portions arranged equidistantly at an angle from each other) to form the same number of divided portions 10 of the annular dose D. It is possible to provide embodiments in which the material outlet 4 has a different number N (e.g., three or five or six, or 2≤N≤15, specifically 3≤N≤9) of divided outlet portions 8 to form the same number of divided portions 10 of the annular dose D.

[0104] The operation of the application device can in particular actuate an application method comprising the following steps: feeding plasticized material (in particular, sealing material suitable for forming a gasket) through at least one channel 3 formed in the feeder 2 until reaching at least one material outlet 4, which extends in a circumferential direction around the axis of the feeder 2.

[0105] The application method comprises the following steps: an annular dose D of material is separated from the material outlet 4 by a separator 7 surrounding the feeder 2, and wherein the separator 7 and the feeder 2 move coaxially with each other. The shear rate (usually referred to as shear rate γ) of the plastic flowing in the channel 3 can be optionally measured on the wall, specifically in the range of 2≤γ≤150sec -1 , more specifically 4≤γ≤80sec -1 within the range.

[0106] The application method comprises the following steps: depositing an annular dose D on an object P, in particular on a substrate B of the object P, wherein the object P may be, for example, a cap for closing a container.

[0107] The separated annular dose D comprises at least one separating portion 10, where "separating portion" means a portion arranged along the circumferential extent of the annular dose D, at which the radial cross-section of the annular dose D is different from the radial cross-section considered in another portion of the annular dose D.

[0108] In this description, the term "radial" refers to the axis around which the annular dose D extends in the circumferential direction. This axis can in particular coincide with the (vertical) axis of the feeder 2.

[0109] The separated annular dose D can in particular comprise two or more separating portions 10 (specifically, four or five separating portions 10, but it is possible to provide a different number N, for example three or six or seven or more than seven separating portions 10, or a certain number N of separating portions 10, where 2 ≤ N ≤ 15, specifically 3 ≤ N ≤ 9), which are angularly spaced apart from each other (specifically, equidistantly) and separated from each other by at least one continuous portion of the material forming the annular dose D (specifically, a continuous portion interspersed with the separating portions 10).

[0110] Each continuous portion can in particular comprise a portion of the material having a constant radial cross-section. Each continuous portion can in particular comprise a portion of the material that extends in length and is shaped as an arc of a circular sector. The continuous portions can in particular be shaped as arcs of circular sectors of the same length. The separating portions 10 can in particular extend longitudinally with the same circumferential length.

[0111] The sum SD of the lengths of the separating portions 10 in the circumferential direction can in particular be less than half of the sum SC of the lengths of the continuous portions (in the form of arcs of circular sectors) in the circumferential direction. Specifically, 0.25*SC < SD < 0.05*SC. The length by which each separating portion 10 extends in the circumferential direction can in particular be 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 dose in the circumferential direction.

[0112] Each separating portion 10 can in particular consist of a cavity not occupied by material. Each separating portion 10 can in particular include a cavity not occupied by material. The radial cross-section of the separating portion 10 can in particular be completely free of sealing material or have less material than the radial cross-section of another portion of the annular dose D.

[0113] Each cavity in the separating portion 10 can in particular be delimited between two end surfaces that face each other in the circumferential direction and are arranged on two respective portions of the annular dose D. The two aforementioned respective portions of the annular dose D can in particular be two portions shaped like circumferential arcs that extend in length along an axis, that is, two material portions or segments in the form of arcs of circular sectors.

[0114] Each separation portion 10 may notably comprise at least one bridge 11 of material joining two portions of the annular dose D, in particular two portions each extending in length and having a constant radial section.

[0115] The cutting frequency of the separator 7 can be chosen according to the amount of material that will have to form the annular dose D. This amount may depend in particular on the dimensions of the object P and / or the dimensions of the gasket G obtained from the moulded dose D. For example, in order to form an annular gasket on a "press / twist-off" cap with a nominal diameter of 51 mm, the annular dose D is divided into four dose portions in the form of circular crown arcs separated by separating portions of the dose without material, wherein each dose portion in the form of a circular crown arc has a weight of 0.25 g or 0.4 g, or a weight value comprised between 0.25 and 0.4 g; or into five dose portions, each having a weight equal to 0.3 g or 0.35 g, or a weight comprised between 0.30 and 0.35 g. According to another embodiment, in order to form an annular gasket on a "press / twist-off" type cap with a nominal diameter of 48 mm, the annular dose D can be divided into three dose portions in the form of circular crown arcs separated by a dose separation portion without material, wherein the weight of each dose portion in the form of a circular crown arc is 0.25 grams; or into four dose portions, each having a weight value equal to 0.3 grams; or into five dose portions in the form of circular crown arcs separated by a dose separation portion without material, wherein the weight of each dose portion in the form of a circular crown arc is 0.25 grams. As can be seen from these embodiments, the annular dose D can have different total weights depending on the specific case. For each specific case, it is possible to have a different number of dose portions, for example by making the total weight of the annular dose D almost constant.

[0116] The annular dose D is separated from the material outlet 4 by means of the separator 7 and deposited on the object P. It is possible to provide an unillustrated step in which the annular dose D deposited on the object P is pressed (for example, punched by annular compression molding) to form a gasket. Fig.29 In FIG. 1 , the display object P (in particular, the closure cap) has an annular gasket G obtained by compression molding of an annular dose D. Fig.30 , the maximum radial dimension of the annular gasket G measured from the inner edge to the outer edge of the gasket has been indicated by G1, while G2 is the maximum radial dimension of the annular recess present at the transition area T of the object P (cover) where the risk of forming undesirable air pockets between the gasket G and the object P is greater, G3 is the maximum height of the gasket G, and W is the thickness of the cover, which includes both the thickness of the gasket G (the thickness obtained at the outer sealing surface of the gasket G which has been further pressed downwards in the molding step) and the thickness of the metal sheet body of the cover.

[0117] The aforementioned thickness W may particularly be included between 0.3 mm and 2 mm, more specifically between 0.55 mm and 1.6 mm, and even more specifically between 0.8 mm and 1.3 mm. In addition, in Fig.30 some dimensions (diameter or thickness) of the annular washer G are indicated only by way of example.

[0118] Reference Fig.28 , the length or maximum circumferential extent of the separating outlet portion 8 (more specifically, the outlet blocking portion) has been indicated by L1, the length or maximum circumferential extent of the separating portion 10 of the dose D (more specifically, the blank portion completely free of material) has been indicated by L2, the length or maximum circumferential extent of the continuous portion of the dose D (more specifically, having a constant complete radial cross-section) included between the two separating portions 10 has been indicated by L3, the maximum width or maximum radial extent of the complete radial cross-section of the continuous portion of the dose D has been indicated by L4, and the height or maximum axial extent of the complete radial cross-section of the continuous portion of the dose D has been indicated by L5.

[0119] It has generally been found that L1~L2 may be determined as L1 < L2 or L1 > L2 depending on the process conditions and rheological properties of the material in some cases.

[0120] In particular, it is possible that by appropriately adjusting the process of applying the dose D and / or appropriately sizing the applying device 1, the L3 / L2 relationship between the length L3 of the continuous portion of the separated annular dose D and the length L2 of the separating portion 10 of the separated annular dose D is included between 2 and 20 (20 ≥ L3 / L2 ≥ 2), more specifically included between 2.5 and 12 (12 ≥ L3 / L2 ≥ 2.5). Selecting this relationship L3 / L2 enables the evacuation of air to be promoted and the risk of forming bubbles or cavities between the washer G and the object P to be reduced.

[0121] If the maximum radial dimension G1 of the annular washer (which must be molded from the annular dose D) is greater than the maximum height G3 of the washer, then more specifically, it is possible to provide (by appropriately adjusting the process of applying the dose D and / or appropriately sizing the applying device 1) a width L4 of the continuous portion of the separated annular dose D that is greater than or equal to the height L5 of the continuous portion of the dose (i.e., if G1 ≥ G3, then L4 ≥ L5), and more specifically, if G1 ≤ G3, then L4 will be ≤ L5. Selecting this relationship L4 / L5 enables the evacuation of air to be promoted and the risk of forming bubbles or cavities between the washer G and the object P to be reduced.

[0122] It is possible to provide (by appropriately adjusting the process of applying the dose D and / or appropriately setting the size of the application device 1) a width L4 of the continuous portion of the separated annular dose D (i.e. L4-G2) which is in particular substantially the same as the maximum radial dimension G2 of the annular recess present at the transition zone T. G2 is particularly likely to be slightly larger than L4, for example not exceeding 10% of L4, i.e. L4 <G2≤1.1*L4。

[0123] Generally, providing one or more separating portions 10 reduces the risk of air pockets forming between the sealing material and the object P on which the annular dose D has been deposited and possibly pressed.

[0124] The annular dose D may in particular be deposited inside an annular wall S of the object P connected to the base B of the object P by means of a transition zone T. The object P may in particular comprise a cover (e.g. a cover made of plastic, or a crown cover, or a cover made of metal, or yet another type of cover), each of which is provided with sealing means, such as, for example, a gasket or a washer. The sealing means are made of the aforementioned sealing material and may be molded from a single type of plastic, or may be made from a combination of different plastics, or may have a multilayer structure.

[0125] The annular dose D can form a polymer gasket, which is especially made 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 polyvinyl chloride (PVC) based compounds.

[0126] Alternatively, for the preparation of the annular dose D, it is possible to use a sealing material comprising thermoplastic elastomers and compounds thereof, for example a combination of polyolefins with styrenic block copolymers, a combination of hard polymers with elastomers, such as, for example, polypropylene and ethylene-propylene PP / EPR, or polypropylene and ethylene propylene diene monomer PP / EPDM.

[0127] In particular, the density of the sealing material (polymer or mixture) used to form the gasket may be comprised between 0.87 and 0.94 g / cm 3 between 0.88 and 0.92 g / cm 3 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. An application method comprising the following steps: Feeding material, in particular sealing material suitable for forming a gasket, through at least one channel (3) formed in a feeder (2), upwardly to at least one material outlet (4), the at least one material outlet (4) extending in a circumferential direction around an axis of the feeder (2); separating an annular dose (D) of material from the material outlet (4) by means of a separator (7) surrounding the feeder (2), wherein the separator (7) and the feeder (2) move coaxially relative to each other; Depositing the annular dose (D) on an object (P), in particular on a substrate of a cap for closing a container; It is characterized in that The separated annular dose (D) comprises one or more partitioning parts (10), i.e. a radial cross-section of a partitioning part (10) of the annular dose (D) is different from a radial cross-section of another part of the annular dose (D), wherein "radial" is understood to refer to an axis around which the annular dose (D) extends in a circumferential direction.

2. A method as claimed in claim 1, wherein the separated annular dose (D) comprises two or more partition portions (10) which are angularly spaced from each other and separated from each other by at least one continuous portion of the material of the annular dose (D), specifically a number N of partition portions (10), wherein 2≤N≤15, more specifically 3≤N≤9; the separated annular dose (D) in particular comprises three, or four, or five, or six partition portions (10), which are angularly spaced from each other and interspersed with continuous portions of the material of the annular dose (D).

3. A method as claimed in claim 2, wherein each continuous portion of the material is shaped like a circular sector arc with an angular range greater than 30°, greater than 45°, or greater than 60°; each continuous portion of the material in particular has a constant radial cross-section.

4. The method as claimed in claim 2 or 3, wherein the sum SD of the lengths of the separating parts (10) in the circumferential direction is smaller than the sum SC of the lengths of the continuous parts in the circumferential direction; specifically, SD<0.75*SC, or SD<0.50*SC, or SD<0.25*SC, or SD<0.10*SC.

5. A method as claimed in any of the preceding claims, wherein a length extending in the circumferential direction of each partition portion (10) is less than 1 / 10, or less than 1 / 20, or less than 1 / 30, or less than 1 / 60 of a length of the annular dose (D) in the circumferential direction.

6. A method as claimed in any of the preceding claims, wherein each partition portion (10) consists of or includes a cavity not occupied by the material, whereby a radial cross-section of the partition portion (10) contains no material or has less material than a radial cross-section of another part of the annular dose (D).

7. A method as claimed in claim 6, wherein each cavity is delimited by two end surfaces facing each other in a circumferential direction and arranged on two separate parts of the annular dose (D); the two separate parts of the annular dose (D), in particular two parts extending in length along an axis, are shaped like a circular arc.

8. A method as claimed in claim 7, wherein each dividing portion (10) comprises at least one bridge (11) of material joining the two portions of the annular dose (D) situated on opposite sides of the dividing portion (10).

9. A method as claimed in any one of the preceding claims, wherein the annular dose (D) is deposited inside an annular wall (S) of the object, the annular wall (S) being connected to a base (B) of the object via a transition zone (T).

10. An application device, in particular for carrying out the method according to any of the preceding claims, comprising: a feeder (2), in particular connected to an extruder for a sealing material suitable for forming a gasket, wherein at least one channel (3) is obtained each time material is fed, in particular plasticized material, upwards until reaching at least one material outlet (4), the at least one material outlet (4) extending in a circumferential direction around an axis of the feeder (2); a separator (7) surrounding the feeder (2) and arranged to separate an annular dose (D) of material from the material outlet (4), the separator (7) and the feeder (2) being movable coaxially with each other, the annular dose (D) being intended to be deposited on an object (P), in particular on a lid for closing a container, in order to form a gasket; It is characterized in that The material outlet (4) comprises at least one separating outlet portion (8) configured to produce a separating portion (10) in the annular dose (D), wherein a radial cross-section of a separating outlet portion (8) is different from a radial cross-section of another portion of the material outlet (4), wherein "radial" is understood to refer to an axis around which the material outlet (4) extends in a circumferential direction; the separating outlet portion (8) particularly comprises an outlet blocking portion or an outlet expansion portion.

11. An apparatus as claimed in claim 10, comprising two or more separated outlet portions (8) which are angularly spaced from each other and separated from each other by at least one continuous portion of the material outlet (4); the apparatus in particular comprises a number N of separated outlet portions (8), wherein 2≤N≤15, more particularly 3≤N≤9; the apparatus in particular comprises three, or four, or five, or six separated outlet portions (8) which are angularly spaced from each other and separated from each other by a continuous portion of the material outlet (4); each continuous portion of the material outlet (4) in particular has a constant channel port.

12. Apparatus as claimed in claim 11, wherein each successive portion of the material outlet (4) extends along a circumferential arc having an angular extent greater than 30°, or greater than 45°, or greater than 60°.

13. An apparatus as described in claim 11 or 12, wherein the sum SD of the lengths of the separated outlet parts (8) of the material outlet (4) in a circumferential direction is smaller than the sum SC of the lengths of the continuous parts of the material outlet (4) in the circumferential direction; specifically, SD<0.75*SC, or SD<0.50*SC, or SD<0.25*SC, or SD<0.10*SC.

14. An apparatus as described in any one of claims 10 to 13, wherein a length extending in a circumferential direction of each separated outlet portion (8) of the material outlet (4) is less than 1 / 10, or less than 1 / 20, or less than 1 / 30, or less than 1 / 60 of a total length of the material outlet (4) in the circumferential direction.

15. An apparatus as claimed in any one of claims 10 to 14, wherein the separating outlet portion (8) comprises at least one cavity (9) obtained on the feeder (2) to form a bridge (11) of a material joining two parts of the annular dose (D) in the separating portion (10) of the annular dose (D).

16. An apparatus as claimed in claim 15, wherein the separated outlet portion (8) comprises an outlet blocking portion integral with the feeder (2), and the cavity (9) comprises a gap formed in the feeder (2) or a groove obtained on the outlet blocking portion.

17. Apparatus according to any one of claims 10 to 16, wherein the separated outlet portion (8) comprises at least one cavity (9) in the form of a slit obtained on an annular cutting element of the separator (7) to form an appendage (12) of material protruding from the annular dose (D).

Images