Patent Application
20080245760
The invention relates to a method for forming compound layers in a sealing cap comprised of substantially a metal material. Such sealing caps, also referred to as “caps”, are used for sealing containers, in particular glass containers, by welding, the upper front end portion of which is provided with scams radially outwards, each of which extending in a tilted manner and being restricted in the perimeter, in order to allow to convert a rotational motion of the “cap” into an axial motion for sealing the container with the described cap and for removing the cap. Thus, the caps are used for the repeated sealing of a container.
The invention relates to a method for manufacturing such a sealing cap, in particular to the fabrication of the compound layer in the peripheral or edge area of the cap, wherein the compound layer forms a seal with the front end of the container and also acts as a mechanical closure at the lateral periphery of the upper end portion of the container. Hence, this area has the double function of sealing and closing such that this area is to be referred to as a sealing and closing or tightening area of the cap (radially outward of a cap level or panel).
The invention also relates to the cap formed by the method (cap, claim 14), which comprises the cap level and the edge area, referred to as “panel area” and “edge area”. These areas blend together via transfer zone, which is to be referred to as cap level edge area.
The invention finally relates to a form mould for positioning and forming an applied compound (as a pre-form) in the cap edge area {claim 20}.
A wide variety of caps is known in the art. One type of cap to be mentioned here is the PT cap as described in EP-B 844 972 (Taber, White Cap), cf. column 1, paragraphs [03], [04], which are here incorporated for the explaining of PT caps. These caps are provided with a compound at the edge area or periphery, which provides for a tightening or closing function and for a sealing function. An axial portion of the compound serves for tightening or closing by an axial pressure, wherein the screw cams of the container to be sealed penetrate the compound, resulting in a mechanical locking, which may be disengaged during use by a rotation only. The “P” represents the axial pressing or closing (P-closing) and the “T” represents the rotational opening (T-opening), cf., claim 14, preamble.
For manufacturing such caps two basically distinct techniques for applying the compound are used. The “lining compound” technique and the “moulded compound” technique, which are explained with reference to
It is an object of the invention to provide a cap having a sealing behavior identical to conventional systems, wherein the amount of compound used is to be reduced in order to reduce costs. In particular, present and future requirements imposed by the sealing of containers to be filled with foods should be met; moreover, within the concept for meeting these requirements a new type of application technique should not be introduced, which may cause additional costs; rather, known methods appropriately to be adapted should be used. The purpose of the invention is to use the conventional technique as much as possible in order to transit to the novel method, cap and moulds as smoothly as possible, while at the same time providing the previously described features of the new cap.
The object is solved by a method, in which two layers of compound are applied in the edge area {claim 1, claim 14}. The two layers of compound are preferably two different types of compound {claim 19, claim 1}, wherein the difference may be of chemical nature or may relate to physical properties. One of the compounds may be an inexpensive one and its food compatibility does not need to be very pronounced, when the compound is used in the radial outward direction with a great distance in the closure area of the sealing and closing area. The second compound may have a higher quality and may thus be more expensive, but it is used in its radial extension in a restricted form, that is, in an area forming a seal with the container at its front end, wherein the second compound may be in contact with the food with its radial inner rim in the sealed state.
The radially inner compound is enhanced with respect to its food compatibility, is, however, reduced in amount, while the compound located radially more outwardly may be optimised with respect to its mechanical strength without having to provide the feature of the food compatibility. This does not exclude that both compounds are of the same chemical and physical nature, however, they will be applied via two different methods to the edge area of the cap in order to cause an interface therebetween, which allows to recognize that a cap {claim 14} formed according to the method {claim 1} is provided with two different compound layers, even though they may be comprised of the same compound material.
With respect to the two methods on the one hand, the previously described method “moulded compound” is used (for the compound located farther radially outwardly), and the lining method (as previously described) is used for the layer of compound located radially further inwardly. Hereby, an overlap zone is created between these two subsequently applied compounds, which causes the above-mentioned intermediate layer, which may be identified in the cross section upon an analysis. Preferably, the compound on the outer edge area with an axially extending tapering more expanded compared to the compound located radially more inwardly, which provides for the front side sealing with the front end of the container.
By referring to the compounds as a first compound and a second compound {claim 1} no ordering is intended, in which these compound layers are applied to the edge area of the cap as a layer (levels). It is only intended to distinguish that the first compound is applied by a first method and the second compound is applied by a second method, wherein both methods are explained.
The order of these methods may be changed. First the layer located in the apron area may be applied. On the other hand, the compound layer located radially more inwardly may be applied first, which is applies according to the lining method. According to the sequence of the methods used there is an overlap zone, in which both compounds overlap and which is preferably located near the circumferential groove {claim 14, feature (a)}. The two methods may also be described such that the radially outer layer does not extend (or does substantially not extend) beyond the inner radial end of the circumferential groove {claim 14, feature (a)}. Alternatively/cumulatively, the compound layer located radially more inwardly may not extend further radially outwardly than the radially outer end of the circumferential groove or the “channel” in the cap {claim 14, feature (b)}.
Furthermore, alternatively/cumulatively the two layers may be distinguished such that one layer extends in a substantially radial manner and the other layer extends in a substantially axial manner, wherein, however, both layers have a given thickness that is adapted to the respective purpose. The substantially radially disposed layer is adapted to the front end sealing of the container. The substantially axially disposed layer is provided for the closing zone so as to cooperate with the screw scams of the container. Both layers together form the sealing and closing zone located at the edge area, which may not necessarily occupy the entire edge area of the cap.
Provided between the edge area and the panel area of the cap (the cap level) is an intermediate zone, which extends radially within the circumferential groove or channel. The compound layer located radially more inwardly does practically no, and preferably not at all, extend into this area so that as less a contact as possible is accomplished with respect to the food sealed in the interior of the container.
The three sub areas of the described sealing and closing zone in the edge area of the cap may be oriented such that they may be referred to as “area 1”, “area 2” and “area 3”. The first area, “area 1”, is in contact with the fill material, thus it is located in the intermediate area (transit zone) between the panel and the edge area. The second area, “area 2”, is the sealing area, which mainly acts as a sealing together with the front end of the container. The third area, “area 3”, serves for embedding the screw thread and for providing for the mechanical closure and the support, respectively, of the sealed cap, after it has been sealed with an axial pressing in order to be opened by screws in a re-sealable manner.
The compound layers applied by the different application methods occupy different geometrical areas in the edge area, that is, the closing area and the sealing area {claim 1}; an overlap zone {claim 9}. By the specific application of the two compound layers different characteristics in the sealing and closing area may be created. Each section of this sealing and closing zone may be given dedicated characteristics. The application of the compounds by the combined use of the Moulded Compound and the Lining Compound serves for the precise alignment of the respective used compound with respect its specific purpose at its specific location within the edge area of the cap {claim 8}.
The lining method is accomplished by injection moulding of a compound, wherein the cap is rotating. After introduction of the compound into a circumferential channel a mechanical post-forming by means of a ring imprint die may be omitted {claim 2}. A rotation of the cap takes place during or after the application inducing a displacement effect, wherein the still flow-like just introduced compound is moved radially outwardly, however only in a restricted amount {claim 1 ;claim 14, feature (b)}. This radial displacement may already begin during the injection.
The compound pre-form also applied by the lining method that is located radialy more outwardly compared to the above-described lining-application is deformed after application {claim 3} by an imprint die, which is a ring or annular die {claim 20}. This second compound is first positioned (during the application by a rotation of the cap), does not exhibit a rotation deformation but a die induced deformation, which extends only into a portion of the sealing and closing zone that comprises at least the closing zone of the cap. This is a substantially axially extending deformation including moderate amounts of a radial deformation when the circumferential channel of the metal shell (the cap raw form) is concerned {claim 15}. As far is the compound extends into the sealing zone {claim 4}, this compound layer is covered by a subsequent lining deformation in the form of rotative application and rotative displacement such that the surface of the sealing zone is formed in the edge area of the cap by the compound applied as the second compound. The resulting overlap zone is then configured such that in axial direction towards to the closing area of the container provided at the front side only the second compound is exposed, while the underlying first compound is covered.
When the order of the methods used is inverted, the second compound geometrically deformed by the moulded compound method does no extend into the sealing zone, but remains in the closing area {claim 3, claim 14, feature (a) and (c)}.
When the compound applied as the second compound also extends into the sealing zone {claim 4}, it is covered there—as previously explained—by the first compound applied afterwards, which is displaced, starting from the radial inner region, by the rotation of the cap.
In other words, the displacement of the two compounds after their respective application in the form of a circumferentially extending toroidal compound string is restricted {claim 5}. This restriction may effected by a ring-like barrier in such a manner that this barrier is located in the cap groove {claim 7, claim 25, claim 27}, or is provided by the annular die form {claim 6}, at the front side of which the barrier is provided as a front side protrusion, like a fin, or is provided as an outer peripheral relatively sharp edge.
During the respective deforming displacement of the second compound either the die or the annular barrier in the circumferential groove of the cap acts as a resistance at a predefined position for the radially inwardly directed flow of the deformed compound and restricts this flow {claim 5}. The flow therefore extends at most into the sealing zone with respect to the point in time of the end of the flow of the second compound caused by the annular die. This inner border does not mean that this inner flow should always extend to the inner end, but it may be completed earlier, for instance by the radially widely outwards located edge of the annular die {claim 21}, the flow may also be ended in a later stage when the flow is restricted by the radially inwardly located edge of the circumferential groove. Intermediate positions are possible {claim 6, 7}, caused by the axial protrusion at the annular die {claim 22} or an annular barrier in the circumferential groove of the cap, as a circumferential fin having a height that is less than a depth of the circumferential groove. Preferably, this barrier is used within the circumferential groove for such a shape of the circumferential groove which has a substantially flat horizontally disposed bottom. In an alternative groove, which substantially extends in wedge-like manner without a flat bottom the circumferential barrier for the radial inward displacement of the second compound (by the die induced deformation) given or barred by the shape and geometry of the annular die.
Further improvements for the structure, the adhesion and also for the other properties of the double layer are obtained by using an additional die that may also provide the compound layer applied radially more inwardly, that is, the first compound, with a pressure force {claim 10}. This application of the pressure force may occur prior to or after the application of the second compound. Upon the axial pressure a more uniform axial height is obtained. The first compound that is displaced radially outwardly in a too intensive manner caused by rotation, thereby resulting in a too large height (thickness), is pushed back to a substantially uniform axial height or thickness, resulting in a two-fold advantage. Created bubbles are reduced and the adhesion between the two compound layers or the adhesion of the first compound layer to the tin cap in the circumferential groove is enhanced. The improvement with respect to the reduction of bubbles and the adhesion occurs in the circumferential stripe forms. A border line of the compound located radially more inwardly, that is, the radially outermost border line is enhanced in view of its non-uniformity (“tail formation”) and may be made more uniform by the additional effect of the die {claim 11}.
The second die has a different configuration compared to that die that is used fort he radial displacement of the radially outer compound {claim 20}. The step of the rotating displacement by centrifugal force for the radially inner compound may be reduced in strength due to the die induced deformation. A double layer of compound material is created, which is free of bubbles, exhibits a good adhesion and lacks abrupt, protruding transitions, thus the double layer has good-quality transitions. This method step providing for a post-shaping or post-forming complements the lining method by an additional process step. This process step acts upon the still flowable first compound for reducing bubbles or improving the adhesion {claim 12}, in a stripe area near the outer edge of the radially inner compound layer.
If the combined groove is used {claim 7}, the additional die enables the formation of a channel at its front end {claim 13}, which is bordered by a fin located radially outwards {claim 24}. A circumferential recess or clearance provides for the formation of the channel in the pressed state in order to receive and radially restrict the compound already applied and displaced by centrifugal force. At the same time the compound is pressed into contact, the adhesion is enhanced and within the smaller narrower groove the condition for an improved separation of surfaces within the overlap zone is achieved. Here the smaller groove has a different function in the context of the larger (broader) groove compared to the same groove during the application method in which the compound located radially more outwardly is applied first {claim 7}. The smaller annular groove within the larger circumferential groove at least hinders the further radial displacement, even though it may not prevent the displacement entirely. In the sense of an existing barrier or resistance it acts, depending on the applied amount and the rounds per minute selected, more or less as a “resistance” with respect to the outward displacement of the still flowable compound located radially inwards. It should be appreciated that this barrier results applying the compound located radially more outwardly in a subsequent step and displacing it by a die in a deforming manner {claim 13, claim 20}.
Based on the two combined application methods the extension of the compounds into the “area 1” (in the panel edge area) may significantly be reduced or even completely avoided in order to reduce the contact with the fill material to a minimum. Substantially, the area used for sealing is occupied by the high-quality compound with an area provided for the sealing, representing the “area 2”. The “area 3” for creating the mechanical support is not or only insignificantly covered by the high-quality compound. Geometric position and spatial extension of the two compound layers, consisting of the first and the second compounds, respectively, which may preferably be different, are thus predetermined in a precise manner with respect to their respective usability and dedication {claim 8}. This predetermination of the geometric extension is especially advantageous for PT caps, which need the compound in the apron region of the cap for closure purposes. Any forms of the circumferential grooves may be used in the area of the apron and the cap level, including a rounded bottom {claim 18}, including a flat bottom {claim 17}, or including an additional fin in the flat bottom. The amount of high-quality compound to be applied, which has to be food compatible, is restricted to region of the “area 2”. The “area 1” is substantially free of the sealing agent and the “area 3” may, for mechanical support, be occupied by a compound of lower quality.
The precise geometry and the extension of the high-quality compound in the “area 2” may be adjusted by the position of the application of the toroidal circumferentially extending compound pre-form, the speed of the rotation of the cap and the amount or mass of the firstly applied compounds. The shape and position of the second compound is determined by the shape and geometry of the die that causes the displacement and the deformation of this compound after application. During the die induced deformation this method is divided into two sections, that is, the introduction or application of the pre-form of the compound and the die induced deformation. During the application of the first compound by the lining method these two method steps may occur concurrently or overlap by rotational application and rotational displacement such that the rotation speed during application may concurrently cause a radial displacement.
Hereby, it is to take into consideration that the cap having its apron facing upwardly is covered by the compounds and the applied compounds are also deformed in this orientation of the cap, while the cap is used after the fabrication and during the normal usage in an inverted state, wherein the compound layers face axially downwards.
Illustrative examples explain and complete the invention in the sense of “embodiments”.
a,
b illustrate the application of a compound layer C* by a method according to “moulded compound”, in two steps, the application of the compound as a pre-form C and the mechanical deformation by a die 40*.
a,
b illustrate the application of a compound pre-form C′ by a method according to “lined compound”, including the application of the compound and the displacement C″ by rotation, in this example without using a die*.
a illustrates three different sections or areas “area 1”, “area 2” and “area 3” in a cap 1. Only an edge area of this cap is shown, with an area of the radially outer end of the cap level 3*, which should no longer be considered herein. The cap 1 is occupied in its edge area 40 by the compound C by a die acting from bottom to top, the compound extending into all three areas “area 1”, “area 2” and “area 3”.
b illustrates the completed cap after the fabrication according to
a illustrates the edge area R of a cap in an axial section including the three enclosed areas, “area 1”, “area 2”, “area 3”, and a compound applied in a circumferential groove.
b illustrates the effect of a die 40 for forming a second compound B at the apron region 4 of the cap 1 of
a,
b illustrate the application of the first compound, followed by applying pressure by another die 50, and a state of the fabrication method of the cap, in which the second compound located B radially more outwardly is deformed in a displacing manner by the die 40 as shown in
a depicts an alternative cap 1, for example the cap of
b depicts the same cap of
a,
b show a manufacturing technique similar to that of
a shows a cap having a circumferential groove 21 having a rounded groove bottom 21a, wherein a die 40 having a different front side configuration compared to
b illustrates the same cap of
a illustrates a further manufacturing method including the application of the radially outer compound B as a first layer according to
b is a later step of the manufacturing method, in which the radially inner compound A is planarized with another die 51.
a illustrates a cap 1 similar to that of
b illustrates a further manufacturing step of the cap of
a,
b illustrates a manufacturing method according to
a,
b illustrate a cap 1 similar to that of
a,
b illustrate two method steps of a method for manufacturing of a cap 1 having two layers of compound and including two die induced deformations.
a,
b illustrates a method including two die induced deformations, wherein cap has a shape as shown in
a illustrates the cap 1 similar to that of
b illustrates a further manufacturing step after the one of
In the figures first the operation of the two mentioned methods of the “moulded compound” and the “lined compound” should be described on the basis of the
First it should be appreciated that the axial sections shown in the figures illustrate the edge area of a cap, which additionally comprises a panel area that is here shown in a non-recessed manner, and a narrow transition area, indicated as panel edge area 3a, provided between the latter areas. The edge area R is the area that has the closing function and the sealing function with respect to the container 90 to be sealed. The panel area hides the opening of the container mostly provided as wide-neck container, which is schematically indicated in
A first method according to
In a second step according to
A second alternative method of applying a compound is illustrated in
The deformation or change of shape according to
Here, three areas, area 1, area 2 and area 3 are given, which form upon moving the die 40*. The same areas are illustrated in
Area 2 extends in radial and partially in axial direction. Area 3 extends substantially in axial direction only. Area 1 substantially extends in radial direction only. All areas 1, 2 and 3 described before are formed from the same compound during the same manufacturing sequence that corresponds to that
One example of the cap according to
Between the panel edge area 3a and the apron section 4 is provided circumferential groove 2, which is schematically indicated. In the following figures different geometries of this circumferential groove 2 are denoted as 20 and 21, respectively. The view into the interior of the cap according to the left hand illustration of
A plurality of manufacturing methods are explained in various pairs of figures. The
In the above-mentioned pairs of figures not all of the process steps are shown, instead only two process steps are illustrated that indicate the difference if the described methods with respect to the prior art.
According to
The die geometry of the die 40 having a radially outer edge 41 restricts the flow motion of the compound layer D in radial direction so that the layer does not extend far but only slightly into the area 2 upon end of the motion and the pressure induced by the die 40.
After the removal of the die 40 the compound layer geometry is determined, that is, a radially more inwardly located first layer, which was applied first and which is the compound layer A, and a radially farther outwardly located layer as the compound layer be, which extends substantially axially and covers the apron area 4 in the area 3. Both layers have different functions, the former one has a sealing function and the latter layer has a mechanical support function.
The “3 areas” (areas or sections), area 1 radially within the outer edge zone 3a of the cap level 3, area 2 as sealing area 10D and area 3 at the apron 4, within the closing area 10V are configured as previously described. As can be seen in the completed cap according to
It is to be noted that the die 40 comprises a body section 40a as a structural component, which is substantially broader compared to the front section, which is configured narrower and which supports the barrier edge or ridge 41. Between these two differently dimensioned sections 40a and front edge of the die 40 a surface 45 extends radially inwardly, which substantially continuously changes its slope for a thickness change of the die 40. The different areas of the die have the different functions as previously described. The annular recess 46 serves for the change with respect to a deformation and displacement of the pre-form of the radially outer compound B; the front side is used for abutting and its peripheral edge serves as a barrier for a further expansion.
In a comparative process sequence the compound layer structure according to
The die 40 comprises on its outer side a recess 46 that extends annularly and determines the shape of the compound layer B. At its inner side the die is provided with a continuously extending surface 45, which leads from a narrow front side to a thicker body area 40a of the die. The narrow front area, at the outer edge area of which also the edge 41 is provided, is narrower compared to the circumferential groove 21 of
In the edge area R a zone 10 is provided as a sealing and closing area, which comprises two sections, that is, a substantially axially extending zone 10V and a substantially radially extending zone 10D. This is a adjacent to the panel edge area 3a in the inner side, which in turn surrounds the panel area 3. Within the sealing zone 10D that corresponds to area 2 the compound A according to
During the application of the compound A according to the
In the
The extension in the thickness direction of the first layer of compound A and the second layer of compound B is not constant, as is in particular illustrated in
Seen from another point, the first applied compound A extends no further in the radial outward direction as a layer than the circumferential groove 21, thus, it does not extend into area 3 but is tightly restricted to area 2 as a closing zone 10D of the closing and sealing zone 10. The orientation substantially in axial direction and substantially in radial direction may be described as L-shaped with respect to the axial section according to
The pairs of
The fin 42 is provided without sharp edges end is rounded. The entire front side of the die 40 opposite the body 40a has a continuously extending surface. In this way, the tin at the inner side will not be damaged end additionally a gentle form of the L-shaped leg of the compound layer B is formed, at which a layer A is applied according to the following figure.
An enlarged view of the overlap area with die engagement 40 is shown in
As is evident from the enlarged view the barring zone does not necessarily need to be an exact line but may extend across a certain piece of surface, which may be curved and annular. The entire front side surface of the die 40 is not necessary for this barrier since the wedge-shaped annular opening between lower surface of the layer A and front side surface of the die 40 faces radially the exterior of the inner edge 43.
For obtaining the configuration of
Both compounds overlap in the circumferential groove 21 radially within area 1 is no compound provided and area 3 is without any extension of the layer of compound A provided with compound B.
In the same order of the die induced deformation of the firstly applied compound B and a deformed compound layer A caused by a rotational motion the
The die 40 is configured as previously described, having a gentle inner surface 45, however, the radially outer edge 41′ is not as thick and sharply provided as in
In the embodiment according to
The intermediate groove has the function of restricting the flow of the first compound layer B applied by the moulded compound technique, wherein the first compound layer B extends substantially axially and as the only layer into “area 3” and also significantly into “area 2” while being radially restricted by circumferential groove 20a.
The circumferential groove 20a is provided with a height (depth) which is lower than the height (depth) of the circumferential groove 20 with respect to the distance between the cap level 3 and the flat bottom geometry of the circumferential groove 20. Accordingly the radially more inwardly positioned compound layer A according to the lining technique described in
The comparison of the different pairs of figures and of the different process results by using the two subsequently applied compound layers demonstrates that the overlap zone near the groove 20 or 21 is configured differently, which does not change anything on the basic distinction of the axial extension and the radial extension of the respective compound layer relative to its extension in the thickness direction oriented perpendicularly. The compound layer B extends more or less into the area 2 as a sealing zone 10D but will in any case covered by the compound layer A for an increasing extension into this area 2 such that the closure effect with the container is always provided by the high quality compound A. This layer of higher quality extends farther in the radial direction than the extension of the circumferential groove. The longest extension is shown in
Area 1 is essentially free of compound. In this region no compound is radially pushed inwards by the application. In this way, it may be avoided that the area of the compound comes into contact with the food. Moreover, it may be avoided that the high-quality compound A of the compound layer A extends too far into the radial outward direction and thus is involved in the closing function or such functions of the cap according to PT manner. The costs for this compound may therefore be reduced for superior chemical or physical characteristics. The physical characteristic of the compound B may be changed in that strong expansion of this compound occurs for enabling the closing function. The chemical and physical characteristics may each precisely adapted to the intended function. The same compound does not need to fulfil several functions in order to perform the required characteristic at the required position along its entire radial and axial extension. The different physical and chemical characteristics may be restricted to the respective required area of the edge area R and, in the present case, to the closing and sealing zone 10, as 10D, 10V.
It should be added that the compound pre-form not illustrated in the pairs of
The forming die 40 is clearly recognizable in its engagement position in
Due to the configuration to the front section it may be avoided that the compound B is significantly displaced in the radial direction. At as hereby restricted to a maximum possible yet not necessarily occurring displacement which is substantially less compared to the actual displacement as is illustrated in the maximum extension of
The flow barrier by a downwardly protruding circumferential fin 42 is directly located at the front side for the contact-free cooperation with the bottom of the groove 20 or 21 wherein than the radially outer edge 41′ is rounded more pronounced compared to the missing fin at the front side of the die 40 according
The radially inner front end 43 of the forming die 40 may relatively freely designed. The flow of the compound B may not reach this end so that the flow may also not enter the area 1 which is to be maintained free from compound. The flow may also not reach the actual sealing face formed by the compound A so that a radial flow is blocked in a substantial portion of area 2.
The lower (in reality: “upper”) remaining section of the annular die, which is not shown in the figures is known from the prior art and may not be explained herein in further detail. It has a support section and a driving mechanism for lifting the die and lowering the same, depending on the operational state. The actuation of the die may be performed mechanically, for instance by hydraulic or pneumatic means. The actuation of the die typically occurs from above, although this is shown in the embodiments for reasons of comparison with respect to the cap in its closing position in a bottom to top actuating manner.
In the intermediate figures not described so far the pairs of
The additional die 50 used according to
Due to the additional deformation of the first compound layer A an enhanced adhesion in the circumferential groove, in particular in the area 21a, is obtained. Therefore, this section of the compound will be freed from possibly formed bubbles or the number of existing bubbles is significantly reduced, which also contributes to an enhanced adhesion.
Due to the die induced deformation and the increased uniformity of the downwardly facing (in reality: upwardly facing) surface also the connection and the overlap according to
The lining technique as a first process step is complemented by die pressure application process as is previously described for the second applied layer. The advantages achieved were described. The usage of the second die 50 may be used in correspondingly modified configuration for such processes, in which the radially inner compound A is not applied first but is applied after the radially outer lying compound layer B and is then formed. Such an embodiment is described later with reference to
Compared to the pairs of
Also the process according to the pair of
In these
By means of the post-planarization according to
Also the process of providing enhanced uniformity of the radially outer borderline of the radially inner compound A is shown in the pair of
The radial outer recess 51c of the die 51 is significantly more exposed compared to
The pair of
A separate description of a process should be provided with reference to
The shape of the circumferential groove 22 is in a way as is explained with reference to
b illustrates a subsequent process step or the stage of the end of several intermediate process steps according to
The axial thickness of the inner compound layer A tapers towards the bottom of the groove 20 at
Each of the die 50 has a body section 50a and is axially sectioned and is illustrated as a partial view. Moreover, they are configured in the same way as die with a drive assembly and a support. The same holds true for the die 51 having a body section 51a and a planarizing surface 51b.
The
An additional pressure driven post-deformation after a rotation based displacement forms the lower surface of this firstly applied compound layer A in a substantially flat manner, as is defined by the shape of the bottom of the recess 55. In the area a3 a line-like improved adhesion is obtained. Also bubbles that may have formed are reduced by the additional deformation step with the die 52a. This die 52a has a body section 52a opposite to the circumferential recess 55, a continuously extending inner wall face 56 and an outer recess 53 which is located opposite to the apron 4 during the illustrated engagement state of the axial pressure application.
The subsequently applied second compound layer B according to
The deforming die 40 corresponds to that of
During the engagement of the die 40 in the area of its front side 42′ and its outer circumferential edge 41b a sharp tapering extending inwardly of the compound layer B is formed. This tip ends at the downwardly protruding ring protrusion with its highest position 42′, which defines a borderline in a line-like manner, beyond which compound B may not extend during its deformation and displacement, that is, it is blocked with respect its radial inward motion. With respect to a corresponding application and effect also the fin-like configuration 42 according to
The front face of the die 40 being substantially wedge-shaped in the cross section includes with its highest line 42′ this barrier zone contacting the radially inner compound A. The radially inner edge line 43 of the die 40 is then not required for blocking the compound flow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10351981.5 | Nov 2003 | DE | national |
| 10352672.2 | Nov 2003 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE04/02424 | 11/2/2004 | WO | 00 | 3/7/2008 |
