CA2354284C - Technique for the partial substitution of damaged metal cords in the sidewalls of medium and large radial tires and the means to permit their substitution - Google Patents
Technique for the partial substitution of damaged metal cords in the sidewalls of medium and large radial tires and the means to permit their substitution Download PDFInfo
- Publication number
- CA2354284C CA2354284C CA 2354284 CA2354284A CA2354284C CA 2354284 C CA2354284 C CA 2354284C CA 2354284 CA2354284 CA 2354284 CA 2354284 A CA2354284 A CA 2354284A CA 2354284 C CA2354284 C CA 2354284C
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- layer
- cords
- tire
- metal cords
- opening
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C13/00—Tyre sidewalls; Protecting, decorating, marking, or the like, thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C73/00—Repairing of articles made from plastics or substances in a plastic state, e.g. of articles shaped or produced by using techniques covered by this subclass or subclass B29D
- B29C73/04—Repairing of articles made from plastics or substances in a plastic state, e.g. of articles shaped or produced by using techniques covered by this subclass or subclass B29D using preformed elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C1/0008—Compositions of the inner liner
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/02—Carcasses
- B60C9/04—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship
- B60C9/08—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship the cords extend transversely from bead to bead, i.e. radial ply
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C73/00—Repairing of articles made from plastics or substances in a plastic state, e.g. of articles shaped or produced by using techniques covered by this subclass or subclass B29D
- B29C73/24—Apparatus or accessories not otherwise provided for
- B29C73/26—Apparatus or accessories not otherwise provided for for mechanical pretreatment
- B29C2073/264—Apparatus or accessories not otherwise provided for for mechanical pretreatment for cutting out or grooving the area to be repaired
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2030/00—Pneumatic or solid tyres or parts thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2030/00—Pneumatic or solid tyres or parts thereof
- B29L2030/007—Sidewalls
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tyre Moulding (AREA)
- Tires In General (AREA)
- Ropes Or Cables (AREA)
Abstract
The invention concerns a technique for the partial substitution of the damaged metal cords in the sidewalls of medium and large size radial tires. The technique also foresees the application of reinforcing elements, while substituting the damaged metal cords in large tires (diameter greater than two metres approximately). The technique consists in carrying out cuts in the tire sidewalls so as to have a trapezoidal opening (5) with side edges parallel to the undamaged radial cords, and the realisation of two trapezoidal slots (4) in which to insert a layer of unvulcanised rubber (1) containing metal cords (1.2) with the ends placed over the metal cords CR of the tire, protruding from the same slots (4), and the application of one or more covering layers to be placed over the perimetral grooves (6) realised by means of grinding along the perimeter of the trapezoidal opening (5) to facilitate attachment.
Description
TECHNIQUE FOR THE PARTIAL SUBSTITUTION OF DAMAGED METAL CORDS IN THE
SIDEWALLS OF MEDIUM AND LARGE RADIAL TIRES AND TI-II: MEANS TO PERMIT
THEIR SUBSTITUTION.
The invention concerns a technique to carry out repairs on the sidewalls of medium and large size radial tires, such as those used for lorries, very large dumpers and diggers and, for example, those used in the lift trucks of contaiiiers, heavy duty cranes which travel over land, operating machinery for shifting materials and very large dumpers etc., which have incurred damage to and/or breakage of the metal cords especially in the case of larger tire damage which, though repairable, compromises the rigidity of the tire sidewalls.
Moreover, the invention also concerns the specific materials used in carrying out the technique, which consist in layers of rubber containing radially arranged metal cords, layers of rubberised fabric, layers of unvulcanised rubber and so on.
In order to carry out the aforementioned repairs on medium-sized tires, as for example those of lorries and medium-sized dumpers, special techniques and patches are used, these being the subject matter of Italian and foreign patents by the same owner N.EP 0353313, designating Italy too; US
Patent N. 5,139,840; Patent N. 196 3887 in Japan; Patent N. 1334375 in Canada.
Said patches, trapezoidal in shape, are vulcanised so as to maintain an arched curved shape and are made up of two layers of only rubber, one layer of rubber containing radially arranged rectilinear metal cords, a layer of rubberised fabric positioned over this last mentioned layer and by a rubber dowel which is inserted into the cut-out window opening in the sidewall of the tire in order to remove the damaged cords.
Concerning much larger tires, having a belt diameter of some metres for which it is necessary to cut out large openings to substitute the damaged radial metal cords and to restore the rigidity of the damaged sidewalls, the current state-of-the-art offers no such technique, suitable means or relative know-how.
On the other hand, for the inevitable manufacturing drawbacks which are also present in medium-sized tires, in some cases the trapezoidal patches cannot be as perfectly applied as they should, since the radial metal cords of the tire walls often do not have a perfectly rectilinear disposition, since they may be more or less waved transversal to the radial cords and remain positioned on the metal cords of the patches thus causing an increase in the rigidity of the tire sidewalls.
This makes it difficult to obtain a perfectly trapezoidal window opening with a radial axis in which to insert the rubber dowel part of the patch, and the realisation of two co-axial trapezoidal slots along the longitudinal length of the window opening into which are inserted the two ends of the metal cord layer not positioned over the dowel.
SIDEWALLS OF MEDIUM AND LARGE RADIAL TIRES AND TI-II: MEANS TO PERMIT
THEIR SUBSTITUTION.
The invention concerns a technique to carry out repairs on the sidewalls of medium and large size radial tires, such as those used for lorries, very large dumpers and diggers and, for example, those used in the lift trucks of contaiiiers, heavy duty cranes which travel over land, operating machinery for shifting materials and very large dumpers etc., which have incurred damage to and/or breakage of the metal cords especially in the case of larger tire damage which, though repairable, compromises the rigidity of the tire sidewalls.
Moreover, the invention also concerns the specific materials used in carrying out the technique, which consist in layers of rubber containing radially arranged metal cords, layers of rubberised fabric, layers of unvulcanised rubber and so on.
In order to carry out the aforementioned repairs on medium-sized tires, as for example those of lorries and medium-sized dumpers, special techniques and patches are used, these being the subject matter of Italian and foreign patents by the same owner N.EP 0353313, designating Italy too; US
Patent N. 5,139,840; Patent N. 196 3887 in Japan; Patent N. 1334375 in Canada.
Said patches, trapezoidal in shape, are vulcanised so as to maintain an arched curved shape and are made up of two layers of only rubber, one layer of rubber containing radially arranged rectilinear metal cords, a layer of rubberised fabric positioned over this last mentioned layer and by a rubber dowel which is inserted into the cut-out window opening in the sidewall of the tire in order to remove the damaged cords.
Concerning much larger tires, having a belt diameter of some metres for which it is necessary to cut out large openings to substitute the damaged radial metal cords and to restore the rigidity of the damaged sidewalls, the current state-of-the-art offers no such technique, suitable means or relative know-how.
On the other hand, for the inevitable manufacturing drawbacks which are also present in medium-sized tires, in some cases the trapezoidal patches cannot be as perfectly applied as they should, since the radial metal cords of the tire walls often do not have a perfectly rectilinear disposition, since they may be more or less waved transversal to the radial cords and remain positioned on the metal cords of the patches thus causing an increase in the rigidity of the tire sidewalls.
This makes it difficult to obtain a perfectly trapezoidal window opening with a radial axis in which to insert the rubber dowel part of the patch, and the realisation of two co-axial trapezoidal slots along the longitudinal length of the window opening into which are inserted the two ends of the metal cord layer not positioned over the dowel.
Moreover, the application of the trapezoidal patches requires a vast array of different sized patches for each type of tire and relative to each damaged area in order to exactly substitute the number of damaged radial cords.
The invention as claimed intends to supply the techniques and means both for the repair and substitution of the radial cords of tires of medium siz-e without causing superimposition of the substituted cords onto the undamaged ones, and to regain the necessary rigidity of the damaged sidewalls of very large tires whose cords must be replaced.
The advantages of the invention, apart from the functional ones, lie, in particular, in the economic aspect, when considering the high costs of medium and large size tires and given that repairs carried out using the technique according to the invention allow for the complete restoration of the function of the tires in question.
Accordingly, in one aspect, the invention provides a method for the partial substitution of damaged metal cords in sidewalls of medium and large sized radial tires and of means to permit their substitution, the method comprising the step of removal of the damaged areas from the sidewall of the tire in order to form a trapezoidal opening the height of which corresponds to the length of the removed cords, the transversal bases of said opening being transversal to the radial cords of the tire and the sides being parallel to the undamaged cords which delimit said opening, the greater base of this opening being located in the area of the edge of the tire belt.
In another aspect, the invention provides a method for partial substitution of damaged metal cords in the sidewalls of medium and large sized radial tires and the means to permit their substitution, medium-sized tires having diameters ranging from I000mm to 2000mm, and large tires being those with a diameter greater than 2000mm, the method comprising:
removing a damaged area from the sidewall of the tire forming a trapezoidal opening, the height of which corresponds to the length of the removed cords, the transversal bases of said opening being transversal to the radial cords of the tire and the sides being parallel to the undamaged cords which delimit said opening, the greater base of the opening being located in the area of the edge of the tire belt;
realisation in the proximity to the basis of the trapezoidal opening of two slots and whose axes of symmetry are co-axial to the radial axis of symmetry of said opening, said slots being realised along the virtual extension of the radial sides of the same opening and being delimited above and below by two sides transversal to the radial cords of the tire, the depth of these slots being such that it uncovers the original cords of the tire, in order to obtain the smaller distance between the metal cords embedded in the layer and said uncovered metal cords of the tire once the layer has been positioned;
grinding and brushing of the inner surface of the tire along the outer perimeter of the trapezoidal shaped opening and the edges of the slots, so to obtain a perimetral groove to the opening and the relative slots being delimited by a width and showing a texture type RMA 2-3;
insertion of a trapezoidal layer of unvulcanised rubber having a maximum width equal to the width of the slots, said .trapezoidal layer embedding a number of metal cords equal to those removed when the metal cords have the same diameter, or greater to those removed when the diameter of the metal cords of the layer is smaller;
application of one or more covering air-tight layers also containing a layer of butyl rubber, on the layer of metal cords, by means of a layer of adhesive unvulcanised rubber so as to cover the perimetral groove, the area of each covering layer being equal to the delimited area of the outer perimeter of the same perimetral groove;
filling, with unvulcanised rubber having suitable characteristics for sidewall tires, of the outer trapezoidal cavities formed by the opening and the outer surface of the layer of metal cords; and vulcanisation, using appropriate means, of the repaired area.
The invention is described in detail as follows with reference made to the enclosed drawings which illustrate respectively:
Fig. 1: the layers which allow for repair of a medium-sized tire;
Fig. 2: the layers which form the protective and finishing layer to be positioned over the layer of metal cords;
Fig. 3: Section AA of fig. 1;
Fig. 4. an example of the application of the layers as in fig. 1, to the sidewalls of a medium-sized radial tire, with parts of unvulcanised rubber filling partially removed fi-om the window opening Gom which the damaged metal cords have been removed;
Fig. 5. a layer of unvulcanised rubber with radial metal cords;
Fig. 6: the technique of application of the layers.as in fig. I to a mediuni-sized tire;
3a Fig. 7: the three layers which allow to carry out the repairing technique on large tires;
Fig. 8: the composition of layers 9 and 10 of fig. 7;
Fig. 9: the technique of application of the layers of fig. 7 on a large size tire;
Fig. 10: a dimensional comparison between a large tire with lateral reinforcements and a medium-sized tire without lateral reinforcements;
Fig. 11. an example of medium and large size tires compared to the average human height;
Fig. 12. adaptability of the layer containing the radial metal cords on the irregular edges of the window opening realised to remove the damaged metal cords of medium and large sized tires;
Background of the invention The invention is based on the fact that the materials which permit the carrying out of the technique have neither been previously and reciprocally made solid nor vulcanised at the same time so as to 3b assume a stable single body, but rather are made up of single components and vulcanised afler their application to the zone to be repaired.
TECHNIQUE OF REPAIRING A MEDIUM-SIZED T'IRE
With regard to medium-sized tires having a diameter of less than 2000mm, the single components are a layer I of unvulcanised rubber containing metal cords and a multiple layer 2 of only rubber, which are applied immediately one after the other to the inner surface of the tire P (fig. 1).
The distortion of unvulcanised rubber fig. 5, of the layer I allows for adaptation of the lateral radial cords 1.2 parallel to the radial cords of the tire, even wlien distorted, as illustrated in fig. 12.
This avoids superimposing the lateral metal cords 1.2 of layer 1 on to the undamaged radial cords CR protruding from the edges of the window opening 5, if they are waved instead of rectilinear.
The metal cords 1.2 of the layer 1 are radially arranged as the radial cords CR in the sidewalls of the tire: the number of cords contained in such a layer, partially trapezoidal in shape, must be the same as, or greater than, the number of the cords removed.
The aim of the second set of layers 2, also trapezoidal in shape, is to protect layer I from oxidation, to create a sufficient air-tight condition, indispensable to tubeless tires, and to fmish off the repaired area.
Said set, see figs. 2 and 4, is made up of a unit of superimposed rubber layers, trapezoidal or rectangular in shape, that is, of an outer layer 12 of anti-oxidant rubber, such as butyl mixture, and of a layer 2.1 of only rubber, consisting in a homogeneous mix, both vulcanised simultaneously so as to form a single unit.
Lastly, on the free side of layer 2.1, a thin sheet of adhesive unvulcanised rubber is applied to be attached to the surface of the layer 1 of metal cords, and to the surface of the perimetral grooves 6, D3 in width, which laterally delimit both the window opening 5 and the slots 4 into which the ends of layer I are inserted; the grooves 6 being realised by grinding and brushing the intact surface surrounding the window opening 5.
Moreover, the second set of layers 2, has a greater area than the layers of metal cords 1, the said greater area being equal in area to that of the grooves 6.
The technique of substituting the damaged cords in a medium-sized tire is based on the following steps:
a) carrying out, on the sidewall two transversal cuts in the direction of the radial cords to be removed and two cuts parallel to the undamaged cords, so as to isolate and remove only the layers of damaged cords and to form a trapezoidal window opening 5.
One of the two transversal cuts is carried out near the edge of the tire belt far enough from the edge of the rim zone 7 in order to realise, on the intact undamaged part of the tire, the slot 4.1 into which the upper end 1.3 of the layer I of metal cords is to be inserted and the other cut in the lower end of the wider slot 4.2 into which the lower end of the same layer I is to be inserted:
the trapezoidal slots 4, are obtained by scraping the rubber which covers the two opposite ends of the radial cords CR of the tire from which the damaged parts have been removed, until the cords are conipletely bare.
The depth S 1 of the slots 4 must be such that it can completely contain layer 1 of the metal cords having a thickness S2 < S 1 and confer a sufficiently high resistance to the radial shifting determined by the tight contact between layer 1 and the bare cords.
b) Grinding and brushing of the inner surface of the tire so as to create the grooves 6, width D3, parallel to the sides of the window opening 5 and to the trapezoidal slots 4.1 and 4.2, to delimit a trapezoidal surface having the same area as that of layer 2 in the inner part of the same grooves.
c) Application of layer 1 of unvulcanised rubber containing the metal cords which will substitute those removed;
d) Application of layer 2 within which layers 2.1 and 12 are vulcanised together so as to form a single unit by means of a thin sheet of adhesive unvulcanised rubber 11 to permit attachment to the opposite surface of the layer of metal cords 1;
e) Filling with unvulcanised rubber 3 the cavity 5.1 of the window opening 5 situated between the outer surface of the tire and the convex surface of the layer 1;
fj Vulcanisation of the repaired area.
TECHNIQUE OF REPAIRING A LARGE TIRE
In the case of very large tires, having a diameter greater than 2000mm, or even larger diameters, see figs. 10 and 11, into which a reinforced and stiffening patch 15 is inserted, such as those used for lift trucks for containers, heavy duty cranes, dumpers etc., the problem to solve is trying to regain the rigidity compromised when the metal cords are substituted, which is the opposite case for medium-sized tires where flexibility is a functional characteristic.
This is solved by using a double protection of the unvulcanised rubber layer 1 containing metal cords made up of two sets of layers, 9 and 10 respectively, instead of only one layer 2 as used when repairing medium-sized tires.
The first protective set 9 is made up of two layers of rubberised fabric 9.1 in which the reinforcing fibre cords which form the fabric are, compared to the axes of the layers 9, angled in a suitable way and conform to the teachings shown in other patents by the sanie owner; a layer of adhesive unvulcanised rubber 11 is placed over the above mentioned layers in order to attach the layer of metal cords to the surface of the layer 1.
Tlie second protective sct 10 is made up of another two layers of rubberised fabric 10.1 having the same characteristics of rubberised fabric layers 9.1, upon which, on the part which remains inside the tire, a layer of butyl rubber 12 is placed to ensure further necessary air-tightness, and on the opposite part, a layer of adhesive unvulcanised rubber 11.
The sets of layers 9 and 10 have an area equal to that delimited by the outer perimeter of the grooves realised by grinding and brushing the zones adjacent to the perimeter of the opening 5.
The layers of the set 9 formed by the rubberised fabrics 9.1 and the layers of sets 10 formed by the layers of rubberised fabric 10.1 and by the layer of butyl rubber 12 are vulcanised separately.
Therefore, the repairing technique for a large tire differs only in that there is the application of two protective groups instead of only one, as in the technique relative to the repairing of medium-size tires and the steps of such an application are the following:
1) carrying out of steps a), b) and c) as in the case of medium-sized tires;
2) Separate vulcanisation of the layers 9.1 of the set 9 and 10.1 and 12 of set 10;
3) Superimposition with the vulcanised set on the metal cords I and attachment thereof by means of a layer of adhesive unvulcanised rubber 11;
4) Superimposition of the vulcanised set 10 to the layer formed by set 9 and attachment thereof by means of a layer of adhesive unvulcanised rubber 11;
The invention as claimed intends to supply the techniques and means both for the repair and substitution of the radial cords of tires of medium siz-e without causing superimposition of the substituted cords onto the undamaged ones, and to regain the necessary rigidity of the damaged sidewalls of very large tires whose cords must be replaced.
The advantages of the invention, apart from the functional ones, lie, in particular, in the economic aspect, when considering the high costs of medium and large size tires and given that repairs carried out using the technique according to the invention allow for the complete restoration of the function of the tires in question.
Accordingly, in one aspect, the invention provides a method for the partial substitution of damaged metal cords in sidewalls of medium and large sized radial tires and of means to permit their substitution, the method comprising the step of removal of the damaged areas from the sidewall of the tire in order to form a trapezoidal opening the height of which corresponds to the length of the removed cords, the transversal bases of said opening being transversal to the radial cords of the tire and the sides being parallel to the undamaged cords which delimit said opening, the greater base of this opening being located in the area of the edge of the tire belt.
In another aspect, the invention provides a method for partial substitution of damaged metal cords in the sidewalls of medium and large sized radial tires and the means to permit their substitution, medium-sized tires having diameters ranging from I000mm to 2000mm, and large tires being those with a diameter greater than 2000mm, the method comprising:
removing a damaged area from the sidewall of the tire forming a trapezoidal opening, the height of which corresponds to the length of the removed cords, the transversal bases of said opening being transversal to the radial cords of the tire and the sides being parallel to the undamaged cords which delimit said opening, the greater base of the opening being located in the area of the edge of the tire belt;
realisation in the proximity to the basis of the trapezoidal opening of two slots and whose axes of symmetry are co-axial to the radial axis of symmetry of said opening, said slots being realised along the virtual extension of the radial sides of the same opening and being delimited above and below by two sides transversal to the radial cords of the tire, the depth of these slots being such that it uncovers the original cords of the tire, in order to obtain the smaller distance between the metal cords embedded in the layer and said uncovered metal cords of the tire once the layer has been positioned;
grinding and brushing of the inner surface of the tire along the outer perimeter of the trapezoidal shaped opening and the edges of the slots, so to obtain a perimetral groove to the opening and the relative slots being delimited by a width and showing a texture type RMA 2-3;
insertion of a trapezoidal layer of unvulcanised rubber having a maximum width equal to the width of the slots, said .trapezoidal layer embedding a number of metal cords equal to those removed when the metal cords have the same diameter, or greater to those removed when the diameter of the metal cords of the layer is smaller;
application of one or more covering air-tight layers also containing a layer of butyl rubber, on the layer of metal cords, by means of a layer of adhesive unvulcanised rubber so as to cover the perimetral groove, the area of each covering layer being equal to the delimited area of the outer perimeter of the same perimetral groove;
filling, with unvulcanised rubber having suitable characteristics for sidewall tires, of the outer trapezoidal cavities formed by the opening and the outer surface of the layer of metal cords; and vulcanisation, using appropriate means, of the repaired area.
The invention is described in detail as follows with reference made to the enclosed drawings which illustrate respectively:
Fig. 1: the layers which allow for repair of a medium-sized tire;
Fig. 2: the layers which form the protective and finishing layer to be positioned over the layer of metal cords;
Fig. 3: Section AA of fig. 1;
Fig. 4. an example of the application of the layers as in fig. 1, to the sidewalls of a medium-sized radial tire, with parts of unvulcanised rubber filling partially removed fi-om the window opening Gom which the damaged metal cords have been removed;
Fig. 5. a layer of unvulcanised rubber with radial metal cords;
Fig. 6: the technique of application of the layers.as in fig. I to a mediuni-sized tire;
3a Fig. 7: the three layers which allow to carry out the repairing technique on large tires;
Fig. 8: the composition of layers 9 and 10 of fig. 7;
Fig. 9: the technique of application of the layers of fig. 7 on a large size tire;
Fig. 10: a dimensional comparison between a large tire with lateral reinforcements and a medium-sized tire without lateral reinforcements;
Fig. 11. an example of medium and large size tires compared to the average human height;
Fig. 12. adaptability of the layer containing the radial metal cords on the irregular edges of the window opening realised to remove the damaged metal cords of medium and large sized tires;
Background of the invention The invention is based on the fact that the materials which permit the carrying out of the technique have neither been previously and reciprocally made solid nor vulcanised at the same time so as to 3b assume a stable single body, but rather are made up of single components and vulcanised afler their application to the zone to be repaired.
TECHNIQUE OF REPAIRING A MEDIUM-SIZED T'IRE
With regard to medium-sized tires having a diameter of less than 2000mm, the single components are a layer I of unvulcanised rubber containing metal cords and a multiple layer 2 of only rubber, which are applied immediately one after the other to the inner surface of the tire P (fig. 1).
The distortion of unvulcanised rubber fig. 5, of the layer I allows for adaptation of the lateral radial cords 1.2 parallel to the radial cords of the tire, even wlien distorted, as illustrated in fig. 12.
This avoids superimposing the lateral metal cords 1.2 of layer 1 on to the undamaged radial cords CR protruding from the edges of the window opening 5, if they are waved instead of rectilinear.
The metal cords 1.2 of the layer 1 are radially arranged as the radial cords CR in the sidewalls of the tire: the number of cords contained in such a layer, partially trapezoidal in shape, must be the same as, or greater than, the number of the cords removed.
The aim of the second set of layers 2, also trapezoidal in shape, is to protect layer I from oxidation, to create a sufficient air-tight condition, indispensable to tubeless tires, and to fmish off the repaired area.
Said set, see figs. 2 and 4, is made up of a unit of superimposed rubber layers, trapezoidal or rectangular in shape, that is, of an outer layer 12 of anti-oxidant rubber, such as butyl mixture, and of a layer 2.1 of only rubber, consisting in a homogeneous mix, both vulcanised simultaneously so as to form a single unit.
Lastly, on the free side of layer 2.1, a thin sheet of adhesive unvulcanised rubber is applied to be attached to the surface of the layer 1 of metal cords, and to the surface of the perimetral grooves 6, D3 in width, which laterally delimit both the window opening 5 and the slots 4 into which the ends of layer I are inserted; the grooves 6 being realised by grinding and brushing the intact surface surrounding the window opening 5.
Moreover, the second set of layers 2, has a greater area than the layers of metal cords 1, the said greater area being equal in area to that of the grooves 6.
The technique of substituting the damaged cords in a medium-sized tire is based on the following steps:
a) carrying out, on the sidewall two transversal cuts in the direction of the radial cords to be removed and two cuts parallel to the undamaged cords, so as to isolate and remove only the layers of damaged cords and to form a trapezoidal window opening 5.
One of the two transversal cuts is carried out near the edge of the tire belt far enough from the edge of the rim zone 7 in order to realise, on the intact undamaged part of the tire, the slot 4.1 into which the upper end 1.3 of the layer I of metal cords is to be inserted and the other cut in the lower end of the wider slot 4.2 into which the lower end of the same layer I is to be inserted:
the trapezoidal slots 4, are obtained by scraping the rubber which covers the two opposite ends of the radial cords CR of the tire from which the damaged parts have been removed, until the cords are conipletely bare.
The depth S 1 of the slots 4 must be such that it can completely contain layer 1 of the metal cords having a thickness S2 < S 1 and confer a sufficiently high resistance to the radial shifting determined by the tight contact between layer 1 and the bare cords.
b) Grinding and brushing of the inner surface of the tire so as to create the grooves 6, width D3, parallel to the sides of the window opening 5 and to the trapezoidal slots 4.1 and 4.2, to delimit a trapezoidal surface having the same area as that of layer 2 in the inner part of the same grooves.
c) Application of layer 1 of unvulcanised rubber containing the metal cords which will substitute those removed;
d) Application of layer 2 within which layers 2.1 and 12 are vulcanised together so as to form a single unit by means of a thin sheet of adhesive unvulcanised rubber 11 to permit attachment to the opposite surface of the layer of metal cords 1;
e) Filling with unvulcanised rubber 3 the cavity 5.1 of the window opening 5 situated between the outer surface of the tire and the convex surface of the layer 1;
fj Vulcanisation of the repaired area.
TECHNIQUE OF REPAIRING A LARGE TIRE
In the case of very large tires, having a diameter greater than 2000mm, or even larger diameters, see figs. 10 and 11, into which a reinforced and stiffening patch 15 is inserted, such as those used for lift trucks for containers, heavy duty cranes, dumpers etc., the problem to solve is trying to regain the rigidity compromised when the metal cords are substituted, which is the opposite case for medium-sized tires where flexibility is a functional characteristic.
This is solved by using a double protection of the unvulcanised rubber layer 1 containing metal cords made up of two sets of layers, 9 and 10 respectively, instead of only one layer 2 as used when repairing medium-sized tires.
The first protective set 9 is made up of two layers of rubberised fabric 9.1 in which the reinforcing fibre cords which form the fabric are, compared to the axes of the layers 9, angled in a suitable way and conform to the teachings shown in other patents by the sanie owner; a layer of adhesive unvulcanised rubber 11 is placed over the above mentioned layers in order to attach the layer of metal cords to the surface of the layer 1.
Tlie second protective sct 10 is made up of another two layers of rubberised fabric 10.1 having the same characteristics of rubberised fabric layers 9.1, upon which, on the part which remains inside the tire, a layer of butyl rubber 12 is placed to ensure further necessary air-tightness, and on the opposite part, a layer of adhesive unvulcanised rubber 11.
The sets of layers 9 and 10 have an area equal to that delimited by the outer perimeter of the grooves realised by grinding and brushing the zones adjacent to the perimeter of the opening 5.
The layers of the set 9 formed by the rubberised fabrics 9.1 and the layers of sets 10 formed by the layers of rubberised fabric 10.1 and by the layer of butyl rubber 12 are vulcanised separately.
Therefore, the repairing technique for a large tire differs only in that there is the application of two protective groups instead of only one, as in the technique relative to the repairing of medium-size tires and the steps of such an application are the following:
1) carrying out of steps a), b) and c) as in the case of medium-sized tires;
2) Separate vulcanisation of the layers 9.1 of the set 9 and 10.1 and 12 of set 10;
3) Superimposition with the vulcanised set on the metal cords I and attachment thereof by means of a layer of adhesive unvulcanised rubber 11;
4) Superimposition of the vulcanised set 10 to the layer formed by set 9 and attachment thereof by means of a layer of adhesive unvulcanised rubber 11;
5) Filling the cavity 5.1 of the outer surface with unvulcanised rubber 3 which has the features of hardness and elasticity similar to those of the rubber of the sidewalls;
6) Vulcanisation of the repaired area.
The advantages of the technique lie above all in the manageability which simplifies application of the protective layers of the layer of the metal cords on large and extensive areas.
Due to the limited thickness of the protective layers, the rolling necessary for expelling air trapped between the superimposed layers may be easily carried out manually.
This is facilitated by the presence of the adhesive layers of unvulcanised rubber 11, not vulcanised together with the components of the sets 9 and 10.
The pre-vulcanisation of the sets 9 and 10, in the subsequent vulcanisation of the repaired area, avoids the onset of anomalous forces on the layer of metal cords I due to the greater adaptability of the reinforcement, and also avoids any possible shifting of the layer of metal cords I from its manufacturing position.
The advantages of the technique lie above all in the manageability which simplifies application of the protective layers of the layer of the metal cords on large and extensive areas.
Due to the limited thickness of the protective layers, the rolling necessary for expelling air trapped between the superimposed layers may be easily carried out manually.
This is facilitated by the presence of the adhesive layers of unvulcanised rubber 11, not vulcanised together with the components of the sets 9 and 10.
The pre-vulcanisation of the sets 9 and 10, in the subsequent vulcanisation of the repaired area, avoids the onset of anomalous forces on the layer of metal cords I due to the greater adaptability of the reinforcement, and also avoids any possible shifting of the layer of metal cords I from its manufacturing position.
Claims (12)
1. A method for partial substitution of damaged metal cords in the sidewalls of medium and large sized radial tires and the means to permit their substitution, medium-sized tires having diameters ranging from 1000mm to 2000mm, and large tires being those with a diameter greater than 2000mm, the method comprising:
removing a damaged area from the sidewall of the tire forming a trapezoidal opening, the height of which corresponds to the length of the removed cords, the transversal bases of said opening being transversal to the radial cords of the tire and the sides being parallel to the undamaged cords which delimit said opening, the greater base of the opening being located in the area of the edge of the tire belt;
realisation in the proximity to the basis of the trapezoidal opening of two slots and whose axes of symmetry are co-axial to the radial axis of symmetry of said opening, said slots being realised along the virtual extension of the radial sides of the same opening and being delimited above and below by two sides transversal to the radial cords of the tire, the depth of these slots being such that it uncovers the original cords of the tire, in order to obtain the smaller distance between the metal cords embedded in the layer and said uncovered metal cords of the tire once the layer has been positioned;
grinding and brushing of the inner surface of the tire along the outer perimeter of the trapezoidal shaped opening and the edges of the slots, so to obtain a perimetral groove to the opening and the relative slots being delimited by a width and showing a texture type RMA 2-3;
insertion of a trapezoidal layer of unvulcanised rubber having a maximum width equal to the width of the slots, said trapezoidal layer embedding a number of metal cords equal to those removed when the metal cords have the same diameter, or greater to those removed when the diameter of the metal cords of the layer is smaller;
application of one or more covering air-tight layers also containing a layer of butyl rubber, on the layer of metal cords, by means of a layer of adhesive unvulcanised rubber so as to cover the perimetral groove, the area of each covering layer being equal to the delimited area of the outer perimeter of the same perimetral groove;
filling, with unvulcanised rubber having suitable characteristics for sidewall tires, of the outer trapezoidal cavities formed by the opening and the outer surface of the layer of metal cords; and vulcanisation, using appropriate means, of the repaired area.
removing a damaged area from the sidewall of the tire forming a trapezoidal opening, the height of which corresponds to the length of the removed cords, the transversal bases of said opening being transversal to the radial cords of the tire and the sides being parallel to the undamaged cords which delimit said opening, the greater base of the opening being located in the area of the edge of the tire belt;
realisation in the proximity to the basis of the trapezoidal opening of two slots and whose axes of symmetry are co-axial to the radial axis of symmetry of said opening, said slots being realised along the virtual extension of the radial sides of the same opening and being delimited above and below by two sides transversal to the radial cords of the tire, the depth of these slots being such that it uncovers the original cords of the tire, in order to obtain the smaller distance between the metal cords embedded in the layer and said uncovered metal cords of the tire once the layer has been positioned;
grinding and brushing of the inner surface of the tire along the outer perimeter of the trapezoidal shaped opening and the edges of the slots, so to obtain a perimetral groove to the opening and the relative slots being delimited by a width and showing a texture type RMA 2-3;
insertion of a trapezoidal layer of unvulcanised rubber having a maximum width equal to the width of the slots, said trapezoidal layer embedding a number of metal cords equal to those removed when the metal cords have the same diameter, or greater to those removed when the diameter of the metal cords of the layer is smaller;
application of one or more covering air-tight layers also containing a layer of butyl rubber, on the layer of metal cords, by means of a layer of adhesive unvulcanised rubber so as to cover the perimetral groove, the area of each covering layer being equal to the delimited area of the outer perimeter of the same perimetral groove;
filling, with unvulcanised rubber having suitable characteristics for sidewall tires, of the outer trapezoidal cavities formed by the opening and the outer surface of the layer of metal cords; and vulcanisation, using appropriate means, of the repaired area.
2. The method of claim 1, wherein the unvulcanised rubber has a hardness of 55 Sh°.
3. The method as claimed in claim 1 or 2, further comprising application on the sidewall of a medium-sized tire having a diameter ranging from 1000mm to 2000mm of a covering layer formed by a layer of rubber and a protective air-tight layer of butyl rubber matched uncured or even vulcanised together so as to form a single layer, to permit with a thin sheet of adhesive unvulcanised rubber the sticking on the metal cords and on the perimetral groove.
4. The method as claimed in any one of claims 1 to 3, further comprising further application of two covering layers on the sidewall of large tire having a diameter greater than 2000mm, the first layer being formed by two layers of rubberised fabric matched uncured or even vulcanised together so as to form a single layer, the second layer formed by other two layers of rubberised fabric and by a layer of butyl rubber matched uncured or even vulcanised together so as to form a single layer, the sticking to the vulcanised set of layers on the opposite surface of the layer of metal cords being obtained by means of two layers of adhesive unvulcanised rubber applied respectively on the first and second of layers.
5. The method as claimed in claim 4, wherein the first layer is applied on the metal cords and groove, followed by the second layer that is superimposed to the first layer in order to restore rigidity to the repaired sidewall.
6. The method as claimed in claim 4 or 5, wherein the reinforcing fibre cords of the rubberised fabric layers making up the first and second layers are angled compared to the symmetry axis of each patch.
7. The method as claimed in claim 1, 2, 4 or 5, wherein the layer of unvulcanised rubber contains a number of metal cords equal to, or greater than, the number of the damaged cords removed from the sidewall of the tire, so as to furnish an equal resistance to traction as the original metal cords of said tire.
8. The method as claimed in claim 3, or 4, wherein the layer is unvulcanised in order to be manually applied and shaped to the opening and to the slots of said opening, in order to adapt the lateral metal cords of layer, parallel to the metal cords of the tire, when these are not perfectly rectilinear due to manufacturing imperfections.
9. The method as claimed in claim 1 or 2, comprising the following means:
(a) a trapezoidal layer of unvulcanised rubber, containing radially arranged metal cords, equal or greater to the number of cords to be substituted, the area of layer being such that it covers the opening obtained by removing the damaged cords, remaining inserted with its surface ends in two slots co-axial to the above mentioned opening and having its lateral edges along the virtual extension of the radial sidewalls of the same tire, the depth of the slots being such that it contains the thickness of the layer; and (b) a covering layer formed by a layer of rubber and by a layer of anti-oxidant and air -tight butyl rubber, matched uncured or even vulcanised together and thereafter covered by a thin layer of adhesive unvulcanised rubber on the surface which must be placed on the layer the area of said layer being greater than that of the above mentioned layer of radial cords having an area which corresponds to the area delimited by the grooves said grooves being obtained by means of grinding and brushing the inner surface of the tire, along the outer perimeter of the opening and the slots.
(a) a trapezoidal layer of unvulcanised rubber, containing radially arranged metal cords, equal or greater to the number of cords to be substituted, the area of layer being such that it covers the opening obtained by removing the damaged cords, remaining inserted with its surface ends in two slots co-axial to the above mentioned opening and having its lateral edges along the virtual extension of the radial sidewalls of the same tire, the depth of the slots being such that it contains the thickness of the layer; and (b) a covering layer formed by a layer of rubber and by a layer of anti-oxidant and air -tight butyl rubber, matched uncured or even vulcanised together and thereafter covered by a thin layer of adhesive unvulcanised rubber on the surface which must be placed on the layer the area of said layer being greater than that of the above mentioned layer of radial cords having an area which corresponds to the area delimited by the grooves said grooves being obtained by means of grinding and brushing the inner surface of the tire, along the outer perimeter of the opening and the slots.
10. The method of claim 9, wherein the layer of rubber is cushion gum.
11. The method as claimed in claim 4, comprising the following means:
(a) one layer of unvulcanised rubber, containing radially arranged metal cords, equal or greater to the number of cords to be substituted, the area of layer being such that it covers the opening obtained by removing the damaged cords, remaining inserted with its surface ends in two slots co-axial to the above mentioned opening and having its lateral edges along the virtual extension of the radial sidewalls of the same tire, the depth of the slots being such that it contains the thickness of the layer; and (b) two covering layers, the first formed by two layers of rubberised fabric matched uncured or even vulcanised together so as to form a single layer, the second formed by another two layers of rubberised fabric and by a layer of butyl rubber, matched uncured or even vulcanised together so as to form a single layer, both covering layers being furnished with a layer of adhesive unvulcanised rubber for their reciprocal sticking and final attachment to the layer and groove.
(a) one layer of unvulcanised rubber, containing radially arranged metal cords, equal or greater to the number of cords to be substituted, the area of layer being such that it covers the opening obtained by removing the damaged cords, remaining inserted with its surface ends in two slots co-axial to the above mentioned opening and having its lateral edges along the virtual extension of the radial sidewalls of the same tire, the depth of the slots being such that it contains the thickness of the layer; and (b) two covering layers, the first formed by two layers of rubberised fabric matched uncured or even vulcanised together so as to form a single layer, the second formed by another two layers of rubberised fabric and by a layer of butyl rubber, matched uncured or even vulcanised together so as to form a single layer, both covering layers being furnished with a layer of adhesive unvulcanised rubber for their reciprocal sticking and final attachment to the layer and groove.
12. The method as claimed in any one of claims 1 to 11, wherein all the layers and the fillings are vulcanised after their application to the area to be repaired.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2354284 CA2354284C (en) | 2001-07-27 | 2001-07-27 | Technique for the partial substitution of damaged metal cords in the sidewalls of medium and large radial tires and the means to permit their substitution |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2354284 CA2354284C (en) | 2001-07-27 | 2001-07-27 | Technique for the partial substitution of damaged metal cords in the sidewalls of medium and large radial tires and the means to permit their substitution |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2354284A1 CA2354284A1 (en) | 2003-01-27 |
| CA2354284C true CA2354284C (en) | 2008-07-15 |
Family
ID=4169604
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2354284 Expired - Fee Related CA2354284C (en) | 2001-07-27 | 2001-07-27 | Technique for the partial substitution of damaged metal cords in the sidewalls of medium and large radial tires and the means to permit their substitution |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2354284C (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2219854B1 (en) * | 2007-11-09 | 2016-03-23 | Compagnie Générale des Etablissements Michelin | Repair patch for radial tires |
| BRPI0722230A8 (en) | 2007-11-29 | 2017-12-26 | Soc Tech Michelin | METHOD FOR APPLYING A REPAIR PATCH TO A DAMAGED PORTION OF A TIRE, AND, TIRE REPAIR PATCH |
| CN102076486A (en) | 2008-06-27 | 2011-05-25 | 米其林研究和技术股份有限公司 | Integrated tire section repair |
| JP5378509B2 (en) * | 2008-06-27 | 2013-12-25 | ミシュラン ルシェルシュ エ テクニーク ソシエテ アノニム | Patches with reinforcements with staggered ends |
| CN102076511B (en) | 2008-06-27 | 2013-12-11 | 米其林研究和技术股份有限公司 | Damaged reinforcement ending preparation for tire repairs |
| BRPI0823067B1 (en) * | 2008-09-10 | 2018-10-16 | Michelin & Cie | method for repairing a damaged part of a tire, and, primed tire repair patch |
| JP6830019B2 (en) * | 2017-04-06 | 2021-02-17 | 株式会社ブリヂストン | Resin metal composite members for tires and tires |
| JP7112480B2 (en) * | 2018-02-14 | 2022-08-03 | 住友電気工業株式会社 | tire |
-
2001
- 2001-07-27 CA CA 2354284 patent/CA2354284C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2354284A1 (en) | 2003-01-27 |
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