CA2057579A1 - Process for recapping pneumatic radial tires - Google Patents
Process for recapping pneumatic radial tiresInfo
- Publication number
- CA2057579A1 CA2057579A1 CA 2057579 CA2057579A CA2057579A1 CA 2057579 A1 CA2057579 A1 CA 2057579A1 CA 2057579 CA2057579 CA 2057579 CA 2057579 A CA2057579 A CA 2057579A CA 2057579 A1 CA2057579 A1 CA 2057579A1
- Authority
- CA
- Canada
- Prior art keywords
- tire
- cord
- arrayed
- radially
- bladder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D30/00—Producing pneumatic or solid tyres or parts thereof
- B29D30/06—Pneumatic tyres or parts thereof (e.g. produced by casting, moulding, compression moulding, injection moulding, centrifugal casting)
- B29D30/52—Unvulcanised treads, e.g. on used tyres; Retreading
- B29D30/54—Retreading
Abstract
A PROCESS FOR RECAPPING PNEUMATIC RADIAL TIRES
ABSTRACT OF THE DISCLOSURE
A process is disclosed for recapping a pneumatic radial tire including a carcass toroidally extended between a pair of bead portions and composed of a ply or plies having cords radially arranged, and a belt composed of three or more cord-arrayed layers arranged on a radially outer side of a crown portion of the carcass and having a split structure in which a central portion of a radially innermost cord-arrayed layer is removed.
A base tire is obtained by removing the other cord-arrayed layer or layers positioned radially outwardly from the radially inner two cord-arrayed layers as well as a tread rubber, while retaining two cord-arrayed layers positioned on a radially inner side of the tire.
Then, at least one cord-arrayed layer and a fresh tread rubber are bonded onto the base tire to form a built tire, applying an internal pressure into the built tire, and the built tire is vulcanized and shaped inside a mold, wherein a diameter (Bo) of the radially outermost cord-arrayed layer of the built tire before application of the internal pressure and a diameter (B) of the radially out-most cord-arrayed layer on the vulcanization and shaping inside the mold satisfy the following inequations:
O ? (B - Bo)/B X 100 ? 0.76.
ABSTRACT OF THE DISCLOSURE
A process is disclosed for recapping a pneumatic radial tire including a carcass toroidally extended between a pair of bead portions and composed of a ply or plies having cords radially arranged, and a belt composed of three or more cord-arrayed layers arranged on a radially outer side of a crown portion of the carcass and having a split structure in which a central portion of a radially innermost cord-arrayed layer is removed.
A base tire is obtained by removing the other cord-arrayed layer or layers positioned radially outwardly from the radially inner two cord-arrayed layers as well as a tread rubber, while retaining two cord-arrayed layers positioned on a radially inner side of the tire.
Then, at least one cord-arrayed layer and a fresh tread rubber are bonded onto the base tire to form a built tire, applying an internal pressure into the built tire, and the built tire is vulcanized and shaped inside a mold, wherein a diameter (Bo) of the radially outermost cord-arrayed layer of the built tire before application of the internal pressure and a diameter (B) of the radially out-most cord-arrayed layer on the vulcanization and shaping inside the mold satisfy the following inequations:
O ? (B - Bo)/B X 100 ? 0.76.
Description
2~7~7~
2-417, 9g3 A PROCESS FOR RECAPPING PNEUMATIC RADIAL TIRES
The present invention relates to a process for recapping pneumatic radial tires. Particularly, the invention relates to the tire-recapping process which can make appropriate the shape of a raw tire with an 05 unvulcanized tread and prevent buckling of the tire.
As compared with bias tires, a pneumatic radial tire, which is provided with a carcass composed of a ply having cords arranged radially and a belt composed of layers having cords arranged, at relatively small angles lo with respect to the tire eguatorial plane, around a crown portion of the carcass, has various advantages such as a smaller movement of a tread rubber constitut-ing a treading surface portion of the tire, excellent durability and wear resistance, and smaller rolling r~sistance owing to a hooping effect of the belt.
Therefore, wlth recent development and propa~ation of express road networks, there is a tendency that such pneumatic radial tires are favorably used for heavy duty vehicles such as trucks or buses.
Particularly, in order to assuredly protec~ the carcass and impart a given circumferential rigidity upon the tire, a tire having a belt composed of four cord-arrayed layers extended substantially over the width of 2 ~ ~ 7 ,..1 ,~ ~
the tires have been frequently used as such pneumatic radial tires for heavy duty vehicles such as trucks or buses.
Although the above belt composed of a plurality of the cord-arrayed layers advantageously function to protect the carcass, increase rigidity of the tread and improve wear resistance and traction performance, the belt has disadvantages in that since excess cornering forces are produced during turnin~ of the vehicle, un-even wearing is likely to occur, and when the tire runson a road having great unevenness, the belt is likely to be damaged due to receipt of large impact from the road.
For this reason, it is a common practice that a cord-arrayed layer located on the radially innermost 1~ side of the plural cord-arrayed layers constituting the belt, that is, the innermost cord-arranged layer, has a split structure in which a central portion is removed, so that cornering forces are advantageously reduced, impacts are adsorbed and a uniform ground-contacting ~0 shape is maintained, without reducing rigidity of the side edge portions of the tread of the tire and durability of the belt.
Incidentally, even when the wearing of tread of the tire proceedsl the carcass ordinarily has sufficient strength. In such a case, a recapping process has been employed, in which a remaining tread rubber is removed 2 ~ .~ 7 ~ 7 ~
from the worn tire, an unvulcanized tread rubber is bonded to a surface of the resulting base tire to build a tire having the unvulcanized tread (hereinafter referred to as "built tire", an internal pressure is o~ applied inside the built tire, and the tire is vulcanized and shaped inside a mold. Recapping ~he tire like this is greatly desirable from the standpoint of effective utilization of natural resources and from the economical standpoint in the case of heavy duty vehicles such as trucks or buses.
Detailed examination of tires actually run revealed that not only a tread rubber but also a cord-arrayed layer constituting a belt were damaged in some cases. In those cases, it is necessary to remove the 1~ damaged cord-arrayed layer and recap the tireO
However~ it is impossible to judge the degree to which the interior of the belt was damaged. For example, in the case of tires having four cord-arrayed layers, up to two cord~arrayed layers positioned on the radially outer side of the tire were damaged in many cases. Therefore, whether the tire should be recapped or not is ordinarily judged by removing two cord-arrayed layers positioned on the radially outer side of the tire and checking the tire. That isr if damage is spread 2~ into the two cord-arrayed layers positioned on the radially inner side of the tire, the tire is disposed of ~7~jrJ~
without being recapped, considering the safety of the tire. When only the two layers positioned on the radially outer side of the tire are damaged, ~hese cord-arrayed layers are removed, and the tire is recapped.
#~ As a matter of fact, thus recapped tires can be used without causing any problem.
As to a recappable tire, a base tire is obtained by removing a tread rubber and two cord-arrayed layers positioned on the radially outer side of the tire, a built tire is formed by bonding fresh two cord-arrayed layers and an unvulcanized tread rubber having a given sectional shape onto the remaining cord-arrayed layer of a belt in the base tire, and shaping and recapping the tire inside a mold by vulcani ation under application o 1~ an internal pressure.
However, with respect to the tire recapped after removing the two cord-arrayed belt layers located on the radially outer side of the tire including the tread rubber, while retaining the radially innermost cord-arrayed layer having the split structure and the othercord-arrayed layer adjacent thereto, a so-called buckling problem occurs during vulcanization and shaping in the moldiny. This occurs as follows:
That is, when the fresh cord-arrayed layers and 9~ the vulcanized tread rubber are to be bonded onto the base tire, and the internal pressure is directly applied 7 ~
to the interior of the base tire to maintain its s ape, the central portion of the base tire which has the two cord-arrayed layers remaining in the radially inner portion of the tire radially outwardly swells owing to o~ removal of the tread rubber and two cord-arrayed layers located on the radially outer side of the tire. As a result, the base tire is deformed to approach sidewall portions spaced in a rotary axis of the tire to each other.
When the built tire is formed by bonding the fresh cord-arrayed layers to constitute the belt and the tread rubber onto the base tire thus deformed, the outer diameter of the built tire is greater than an inner diameter of the mold for the succeeding vulcanization 1~ and shaping. In this case, the recapped tire cannot avoid influence of the above deformation of the tire.
That is, when the raw tire is to be vulcanized and shaped, the tread rubber enters between split faces of the molding, or the buckling problem occurs in such a manner that the radially inner central portion of the tread collects at the central portion of the tread rubber and projects radially inwardly. When such a recapped tire is filled with an internal pressure, a tread surface is deformed in a radially projecting convex fashion. This causes a non-uniform ground-contacting shape and large strain at ends of the belt.
2 ~ ~ 7 ~ rl ~
Consequently, an intended durability of the belt can hardly be attained. Such defects occur not only when the cord-arrayed layers and the tread rubber are bonded onto the base tire under direct application of the o~ internal pressure but also when a bladder havin~ a substantially uniform thickness and being inflatable upon application of a pressurizing fluid is used.
~ he present invention has been accomplished in view of the above-mentioned problems, and is aimed at the provision of a process for recapping pneumatic radial tires, while preventing occurrence of buckling.
In order to attain the above-mentioned object, the present invention relates to the process for recapping a pneumatic radial tire including a carcass 1~ toroidally extended between a pair of bead portions and composed of a ply or plies having cords radially arranged, and a belt composed of three or more cord-arrayed layers arranged on a radially outer side of a crown portion of the carcass and having a split structure in which a central portion of a radially innermost cord-arrayed layer is removed, said process including the steps of obtaining a base tire by retaining two cord-arrayed layers positioned on a radially inner side of the tire and removing the other 8~ cord-arrayed layer or layers positioned radialIy outwardly from the radially inner two cord-arrayed 7~7~
layers as well as a tread rubber, bonding at least one cord-arrayed layer and a fresh tread rubber onto the base tire to build a built tire, applying an internal pressure into the built tire, and vulcanizing and shaping the built tire inside a mold, wherein a diameter (Bo) of the radially outermost cord-arrayed layer of the built tire before application of the internal pressure and a diameter (B) of the radially outmost cord-arrayed layer on the vulcanization and shaping inside the mold satisfy the following inequations:
0 < (B - Bo~/B X lO0 < 0.76.
According to the present invention, the following countermeasures are considered preferable.
l. When the built tire is formed, a bladder is used, which gives a smaller amount swelled radially outwardly on the application of the internal pressure as compared with an amount swelled axially outwardly.
2. A bladder is used, which has that thickened central portion to be contacted with an inner surface of a crown portion of the base tire which is thicker than the remaining portion of the bladder.
2-417, 9g3 A PROCESS FOR RECAPPING PNEUMATIC RADIAL TIRES
The present invention relates to a process for recapping pneumatic radial tires. Particularly, the invention relates to the tire-recapping process which can make appropriate the shape of a raw tire with an 05 unvulcanized tread and prevent buckling of the tire.
As compared with bias tires, a pneumatic radial tire, which is provided with a carcass composed of a ply having cords arranged radially and a belt composed of layers having cords arranged, at relatively small angles lo with respect to the tire eguatorial plane, around a crown portion of the carcass, has various advantages such as a smaller movement of a tread rubber constitut-ing a treading surface portion of the tire, excellent durability and wear resistance, and smaller rolling r~sistance owing to a hooping effect of the belt.
Therefore, wlth recent development and propa~ation of express road networks, there is a tendency that such pneumatic radial tires are favorably used for heavy duty vehicles such as trucks or buses.
Particularly, in order to assuredly protec~ the carcass and impart a given circumferential rigidity upon the tire, a tire having a belt composed of four cord-arrayed layers extended substantially over the width of 2 ~ ~ 7 ,..1 ,~ ~
the tires have been frequently used as such pneumatic radial tires for heavy duty vehicles such as trucks or buses.
Although the above belt composed of a plurality of the cord-arrayed layers advantageously function to protect the carcass, increase rigidity of the tread and improve wear resistance and traction performance, the belt has disadvantages in that since excess cornering forces are produced during turnin~ of the vehicle, un-even wearing is likely to occur, and when the tire runson a road having great unevenness, the belt is likely to be damaged due to receipt of large impact from the road.
For this reason, it is a common practice that a cord-arrayed layer located on the radially innermost 1~ side of the plural cord-arrayed layers constituting the belt, that is, the innermost cord-arranged layer, has a split structure in which a central portion is removed, so that cornering forces are advantageously reduced, impacts are adsorbed and a uniform ground-contacting ~0 shape is maintained, without reducing rigidity of the side edge portions of the tread of the tire and durability of the belt.
Incidentally, even when the wearing of tread of the tire proceedsl the carcass ordinarily has sufficient strength. In such a case, a recapping process has been employed, in which a remaining tread rubber is removed 2 ~ .~ 7 ~ 7 ~
from the worn tire, an unvulcanized tread rubber is bonded to a surface of the resulting base tire to build a tire having the unvulcanized tread (hereinafter referred to as "built tire", an internal pressure is o~ applied inside the built tire, and the tire is vulcanized and shaped inside a mold. Recapping ~he tire like this is greatly desirable from the standpoint of effective utilization of natural resources and from the economical standpoint in the case of heavy duty vehicles such as trucks or buses.
Detailed examination of tires actually run revealed that not only a tread rubber but also a cord-arrayed layer constituting a belt were damaged in some cases. In those cases, it is necessary to remove the 1~ damaged cord-arrayed layer and recap the tireO
However~ it is impossible to judge the degree to which the interior of the belt was damaged. For example, in the case of tires having four cord-arrayed layers, up to two cord~arrayed layers positioned on the radially outer side of the tire were damaged in many cases. Therefore, whether the tire should be recapped or not is ordinarily judged by removing two cord-arrayed layers positioned on the radially outer side of the tire and checking the tire. That isr if damage is spread 2~ into the two cord-arrayed layers positioned on the radially inner side of the tire, the tire is disposed of ~7~jrJ~
without being recapped, considering the safety of the tire. When only the two layers positioned on the radially outer side of the tire are damaged, ~hese cord-arrayed layers are removed, and the tire is recapped.
#~ As a matter of fact, thus recapped tires can be used without causing any problem.
As to a recappable tire, a base tire is obtained by removing a tread rubber and two cord-arrayed layers positioned on the radially outer side of the tire, a built tire is formed by bonding fresh two cord-arrayed layers and an unvulcanized tread rubber having a given sectional shape onto the remaining cord-arrayed layer of a belt in the base tire, and shaping and recapping the tire inside a mold by vulcani ation under application o 1~ an internal pressure.
However, with respect to the tire recapped after removing the two cord-arrayed belt layers located on the radially outer side of the tire including the tread rubber, while retaining the radially innermost cord-arrayed layer having the split structure and the othercord-arrayed layer adjacent thereto, a so-called buckling problem occurs during vulcanization and shaping in the moldiny. This occurs as follows:
That is, when the fresh cord-arrayed layers and 9~ the vulcanized tread rubber are to be bonded onto the base tire, and the internal pressure is directly applied 7 ~
to the interior of the base tire to maintain its s ape, the central portion of the base tire which has the two cord-arrayed layers remaining in the radially inner portion of the tire radially outwardly swells owing to o~ removal of the tread rubber and two cord-arrayed layers located on the radially outer side of the tire. As a result, the base tire is deformed to approach sidewall portions spaced in a rotary axis of the tire to each other.
When the built tire is formed by bonding the fresh cord-arrayed layers to constitute the belt and the tread rubber onto the base tire thus deformed, the outer diameter of the built tire is greater than an inner diameter of the mold for the succeeding vulcanization 1~ and shaping. In this case, the recapped tire cannot avoid influence of the above deformation of the tire.
That is, when the raw tire is to be vulcanized and shaped, the tread rubber enters between split faces of the molding, or the buckling problem occurs in such a manner that the radially inner central portion of the tread collects at the central portion of the tread rubber and projects radially inwardly. When such a recapped tire is filled with an internal pressure, a tread surface is deformed in a radially projecting convex fashion. This causes a non-uniform ground-contacting shape and large strain at ends of the belt.
2 ~ ~ 7 ~ rl ~
Consequently, an intended durability of the belt can hardly be attained. Such defects occur not only when the cord-arrayed layers and the tread rubber are bonded onto the base tire under direct application of the o~ internal pressure but also when a bladder havin~ a substantially uniform thickness and being inflatable upon application of a pressurizing fluid is used.
~ he present invention has been accomplished in view of the above-mentioned problems, and is aimed at the provision of a process for recapping pneumatic radial tires, while preventing occurrence of buckling.
In order to attain the above-mentioned object, the present invention relates to the process for recapping a pneumatic radial tire including a carcass 1~ toroidally extended between a pair of bead portions and composed of a ply or plies having cords radially arranged, and a belt composed of three or more cord-arrayed layers arranged on a radially outer side of a crown portion of the carcass and having a split structure in which a central portion of a radially innermost cord-arrayed layer is removed, said process including the steps of obtaining a base tire by retaining two cord-arrayed layers positioned on a radially inner side of the tire and removing the other 8~ cord-arrayed layer or layers positioned radialIy outwardly from the radially inner two cord-arrayed 7~7~
layers as well as a tread rubber, bonding at least one cord-arrayed layer and a fresh tread rubber onto the base tire to build a built tire, applying an internal pressure into the built tire, and vulcanizing and shaping the built tire inside a mold, wherein a diameter (Bo) of the radially outermost cord-arrayed layer of the built tire before application of the internal pressure and a diameter (B) of the radially outmost cord-arrayed layer on the vulcanization and shaping inside the mold satisfy the following inequations:
0 < (B - Bo~/B X lO0 < 0.76.
According to the present invention, the following countermeasures are considered preferable.
l. When the built tire is formed, a bladder is used, which gives a smaller amount swelled radially outwardly on the application of the internal pressure as compared with an amount swelled axially outwardly.
2. A bladder is used, which has that thickened central portion to be contacted with an inner surface of a crown portion of the base tire which is thicker than the remaining portion of the bladder.
3. In the countermeasure 2, an axial width of the thickened central portion is greater than that of the central portion removed from the radially innermost 2B cord-arrayed layer, but smaller than a maximum width of the tire.
4. The ratio of an outer diameter of the bladder in a free state filled with no internal pressure to the diameter of the radially inner surface of the base tire in a free state filled with no internal pressure is not o~ more than 240%.
The ratio of a sum of a total length of the radially inner surface in the radial section of the base tire and a value obtained by deducing the outer diameter of the bladder from the diameter of the bead base portion to the width of the bladder in a free state filled with no internal pressure is not less than 110%.
6. The following inequation: (M-N)/2 x 0.65 ~
(d-N)/2 is met, in which d is diameter of each of a pair of holding rings which support the base tire at bead 1~ portions and sidewall portions of the base tire from - axially outer sides and M and N are a diameter of the base tire at a maximum width location, and an outer diameter of the base tire at the bead portion, respec-tively, in the state that the base tire is in a free 2~ state filled with no internal pressure.
~ ccording to the present invention, since the outer diameter of the built tire is made appropriate relative to the mold for vulcanizing and shaping, occurrence of the buckling can significantly be prevented, and the ground-contacting shape of the recapped tire can be made uniform.
7 ,3 r~ 9 These and other objects, features and advantages of the invention will be appreciated upon reading of the following description of the inven~ion when taken in conjunction with the attached drawings, with the under-o~ standing that some modifications, variations and change~of the same could be made by the skilled person in the art to which the invention pertains without departi.ng from the spirit of the invention or the scope of claims appended hereto.
For a better understanding of the invention, reference is made to the attached drawings, wherein:
Fig. 1 is a sectional view of a built tire to which the present invention is applied;
Fig. 2~a) is a sectional diagram illustrating 1~ the dimension of a fourth cord-arrayed layer of a built tire in a non-restraint state;
Fig. 2(b) is a sectional diagram illustrating the dimension of the fourth cord-arrayed layer of the built tire inside a mold during a vulcanizing-shaping step;
Fig. 3(a) is a sectional view of a part of a bladder favorably applicable to the recapping process according to the present invention;
Fig. 3(b) is a schematic diagram showing the relationship between the radial growth of the base tire and the applied pressure;
~i7 ~ 1~
Fig. 45a) is a diagram showing the relationship between the elongation rate of the bladder shown in Fig. 3(a) in the circumferential direction and the number of times at which the bladder is expanded and o~ contracted by feeding and removing the internal pressure to the bladder;
Fig. 4(b) is a diayram showing the relationship between the radial expansion rate of the bladder shown in Fig. 3(a) and the average difference of radially grown amount between tread shoulders when the internal pressure of 0.5 kg/cm2 is applied to the bladder;
Fig, 5(a) is a sectional view illustrating holding rings to favorably cooperate with the bladder shown in Fig. 3(a): and 1~ Fig. 5(b) is a diagram showing the relationship between the outer diameter of the holding ring and the deviated amount of the center of the base tire.
Fig. 1 is a sectional view showing a raw tire 10 built by bonding two cord-arrayed layers and a un-vulcanized tread rubber onto a base tire having two cord-arrayed layers according to the present invention.
A carcas~ 12 includes a ply having cords radially arranged and toroidally extending between a pair of bead portions 14 spaced from each other in a rotary axis direction of the tire. Although it is illustrated that the carcass 12 of the built tire 10 has a single cord-2 ~ ~ 7 '~
arrayed layer, a plurality oE cord-arrayed layers may be used depending upon the specification of the tire.
In that case, at least one o the radial cord arrangement layers constituting the carcass is turned up around a bead core 16 of the bead portion 14 at each of the opposite ends.
Along the outer periphery of a crown portion of the carcass 12 are successively arranged four cord-arrayed layers 18, 20, 22 and 24 from the radially inner side to the radially outer side of the tire in this order, and these cord-arrayed layers form a belt 26.
The first cord-arrayed layer 18 is located on the radially inner side of the tire, and has a split structure in which a tire-widthwise central portion is 1~ removed over the circumferential direction of the tire.
Cords of the layer 18 are uniformly inclined upwardly in the right direction at a relatively small cross angle, for example, at a cross angle of 45-52, with respect to the the equatorial plane of the tire not shown.
The second cord-arrayed layer 20 is located adjacently on the radially outer side of the radially innermost cord-arrayed layer 18, and the cords of the layer 20 are uniformly inclined upwardly in the right direction at a relatively small cross angle, for example, at a cross angle of 18-20, with respect to the equatorial plane of the tire.
~ 3 The third cord-arrayed layer 22 is located adjacent to the second cord-arrayed layer 20, and the cords of the third layer 22 are inclined in a direction reverse to that of the cords of the second cord-arrayed 0~ layer 20 radially inwardly adjacent thereto, that is, inclined upwardly in the left direction, with respect to the equatorial plane of the tire. The angle defined by the cords of the third cord-arrayed layer and the tire equa~orial plane is in a range of 18-20 or in a range lower than this range.
In the fourth cord-arrayed layer 24 located on the radially outer side of the belt 26, the angle defined between the cords of the layer 24 and the tire equatorial plane is substantially equal to the cross 1~ angle defined by the cords of the third cord-arrayed layer and the tire equatorial plane, The built tire 10 is obtained by bonding an unvulcanized tread rubber 28 adjacent to and on the radially outer side of the belt 26. A recapped tire is obtained by applying an internal pressure into the built tire to press it against the inner surface of a given mold, and vulcanizing and shaping the built tire.
Different from the built tire 10 shown in Fig. 1, the inclined direction of the cords of each of the cord-26 arrayed layers constituting the belt 26 may be reversedor their inclined directions may be chan~ed to quite . .
: ' ' ', different ones.
Such a recapped tire may be obtained as follows:
First, a tread rubber of a tire to be recapped is removed by buffing, and then a base tire is obtained by removing third and fourth cord-arrayed layers located on the radially outer side of the tire along a line segment L denoted by a dot-and-dash line in Fig. 1 by using an appropriate cutter. A degree at which the tire is damaged is examined, and a base tire in which damage is not propagated into first and second coxd-arrayed layers 18 and lg located radially inside the tire is selected.
The surface shape and the dimension of the base tire are adjusted by using a wire brush or the like, an appropriate adhesive is applied to the resulting base tire, and a wide unvulcanized cushion sheet having a thickness of, for example, 0.5 mm - 1.0 mm is bonded thereto. By so doing, the excellent bonding between the remaining second cord-arrayed layer 20 and a third cord-arrayed layer 22 to be newly bonded can be assured.
When the width of the cushion sheet is greater than that of the below-mentioned third cord-arrayed layer 22, preferably substantially equal to that of the base tire, adhesion between the below-mentioned unvulcanized tread rubber and the brushed surface of the base tire can be improved.
In order to prevent separation of the third cord-arrayed layer 22 bonded onto the cushion sheet from an end, a narrow unvulcanl2ed cushion rubber (not shown) having a thickness of 0.5 ~ 0.8 mm is bonded, correspond-ing to each of widthwise end portions of the third cord-arrayed layer, between each of the widthwise end portions of the third cord-arrayed layer and the cushion sheet along the circumferential direction of the tire.
Next, the third cord-arrayed layer 22 is bonded to a given portion of the wide cushion sheet. The third cord-arrayed layer 22 is bonded onto the base tire such that the widthwise end portions of the layer 22 may be located on the cushion sheet.
Then, a new fourth cord-arrayed layer 24 is 1~ bonded adjacent the third cord-arrayed layer 22 and radially outwardly on the rentral portion of the layer 22. Finally, the built tire 10 is obtained by bonding a unvulcanized tread rubber adjacent 10 and on the radially outer side of the fourth cord-arrayed layer 24.
After the built tire 10 is placed in a given mold, the built tire is filled with an internal pressure, and vulcanized and shaped. According to the present invention, the Eollowing relationship of 0 S (B - Bo)/B
x 100 < 0.76 is satisfied. In these inequations, Bo is the outer diameter of the fourth cord-arrayed layer of the built tire to which no internal pressure i8 applied, ' ' ' .
as shown in Fig. 2(a), and B is the outer diameter of the fourth cord-arrayed layer 24 when the internal pressure is applied to the built tire, as shown in Fig. 2tb) when the raw tire is to be vulcanized and shaped in the mold.
As shown in Table shown below~ if (B - Bo)/B x 100 is less than zero, that is, if the outer diameter Bo of the built tire undertaking no restraint is greater than the inner diameter of the mold, the resulting recapped tire is buckled or the tread rubber enters between split faces of the mold. On the other hand, if ~B - Bo)/B x 100 is greater than 0.76, that is, if the built tire cannot be sufficiently pressed against the inner surface of the mold, sponge is formed in the tread of the recapped tire.
Table 1 _ _ (B-BU)/B x 100 Tire sectional shape _ ~
-0.1 buckled _ 0~0 good .... __ _ 0.4 good ", ._ 0.76 good 0.80 sponge formed 1.0 sponge formed 2~7~
In order that the built tire and the vulcanized and shaped tire, and particularly the fourth cord~
arrayed layer constituting the belt may satisfy the above-mentioned relationship, it is preferable to use a bladder which can swell the base tire for the formation of the built tire, while suppressing radial swelling of the base tire. One of such bladders is shown in Fig. 3.
Since the bladder is laterally substantially symmetrical with respect to the widthwise central portion, only a left half portion of the bladder is shown for simplicity.
As is the same with known bladders, the bladder 30 is made of a bag-shaped rubber or rubbery elastic member having flexibility, gas-tightness and heat 1~ resistance. The bladder is designed such that when the bladder is inflated with a pressurizin~ fluid, the thickness hl of a portion contacting the inner face of the crown of the base tire i9 greater than that h2 of the remainin~ portion, and the width ~ of the thicker ao portion of the bladder is greater than the width of that portion of the first cord-arrayed layer 18 constituting the belt which is removed from the layer 18, but smaller than the maximum width of the tire. A bladder body is supported by a support member 34.
a6 If the width e of the thicker portion of the bladder is smaller than the width of the central hollow ~ ^3 portion of the first cord-arrayed layer 18, the base tire is locally expanded radially outwardly at the central hollow portion as well as a portion near the hollow central portion. If the width e of the bladder is greater than the maximum width of the tire, it is likely that the bladder is more greatly swelled in the tire-radial direction then in the tire-width direction.
Rigidity of that thicker portion of the bladder 30 which is pressed against the inner surface of the crown portion of the base tire is higher as compared with that of the remaining portion of the bladder which contacts the other portion of the tire, such as sidewalls. Thus, the thicker portion of the bladder less greatly swells in the radially outer direction than lB in the widthwise outer direction, when the internal pressure is applied to the bladder. Accordin~ly, the bladder swells to substantially follow the shape of the inner surface of the base tire free from restraint.
That is, when the internal pressure is applied to the ao bladder, the belt portion remaining in the base tire is not greatly swelled in the radially outward direction.
Fig. 3(b) shows the radially outwardly swelled amount of a base tire when a pressurizing fluid was applied to each o~ a bladder having the structure shown a~ in Fig. 3~a), and a known bladder having a almost uniform thickness and a base tire in which the -~8-rl ~
pressurizing Eluid was directly applied without using any bladder.
On the o~her hand, since the bladder 30 i5 repeatedly expanded or contracted in the circumferential direction, following the feeding and discharging of the pressuri2ing fluid into the bladder, a ratio Sc of the diameter ED of the inner surface of the base tire in the free state to the outer diameter DB of the bladder in a free state not influenced by the internal pressure with the pressuring fluid is set at 240% or less.
As shown in Fig. 4(a), if the ratio i8 more than 240~, durability of the bladder 30 repeatedly subjected to the expansion and contraction is greatly reduced.
Preferably, the ratio 5c is not more than 190%. The l~ ratio Sc denotes a circumferential expandable degree following the feeding and discharging of the pressurizing fluid for the bladder.
Since the bladder 30 repeatedly radially expands and contracts, following the feeding and discharging of ~0 the pressurizing fluid, a ratio Sr of a value C, which is obtained by adding a total length of the radially inner surface in the radial section of the base tire to a value obtained by deducing the outer diameter D of the bladder from the diameter of the bead base portion, 2* relative to the width W of the bladder 30 is set at 110%
or more. As shown in Fig. 4(b), if the ratio Sr is less ~Y~7~
than 110%, the bladder is so great that the bladder cannot be appropriately inserted into the base tire to make centering alignment impossible, and the growth in the radius becomes dif~erent between the opposite tread o~ shoulders of the base tixe at locations spaced from the equatorial plane of the tire by 70 mm when the tire is inflated at an internal pressure of 0.5 kg/cm2.
Further, since the shape of the base -tire has been ordinarily deformed, different from an original shape of a fresh tire owing to use, it is advantageous that a part of a portion between the bead portion and at least the sidewall portion is held such that the base tire is uprightly held symmetrically with respect to the equatorial plane. Therefore, it is advantageous to use 1~ a member capable of holding the bead portion and the sidewall portion of the base tire from the exterior of the tire in a desired shape in cooperation with the bladder 30 inflated inside the base tire. For example, a pair of holding rings 36 shown in Fig. 5(a) is ~0 advantagèously used. In Fig. S(a), an imaginary line denotes the bladder in the contracted state.
The outer diameter d of the holding ring 36 is selected to satisfy the relationship: ~M - N)/2 x 0.65 < (d ~ N)/2 in which M and N are a diameter of the base a6 tire at a maximum width location before application of the internal pressure, and a diameter of the bead base portion of the base ~ire, respectively. As shown in Fig. 5(b), if [(d - N)/2]/[(M - N)/2]is less than 0.65, the center of the base tire is greatly deviated from a preset center.
o~ After the base tire is set by using the bladder 30 and the holding rings 36 as shown in Fig. 5(a~, the internal pressure to be applied to the bladder is appropriately selected so that the radially outermost cord-arrayed layer of the built tire formed may satisfy the inequations tl), and then a fresh cord-arrayed layer and an unvulcanized tread rubber are bonded to the base tire, thereby obtaining the built tire ~atisfyin~ the inequations (l).
As having been described before, according to 1~ the recapping process of the present invention, the recapped tire free from occurrence of buckling and entering of the tread rubber into the split faces of the mold when the tire is vulcanized and shaped in the mold can be obtained.
~B
The ratio of a sum of a total length of the radially inner surface in the radial section of the base tire and a value obtained by deducing the outer diameter of the bladder from the diameter of the bead base portion to the width of the bladder in a free state filled with no internal pressure is not less than 110%.
6. The following inequation: (M-N)/2 x 0.65 ~
(d-N)/2 is met, in which d is diameter of each of a pair of holding rings which support the base tire at bead 1~ portions and sidewall portions of the base tire from - axially outer sides and M and N are a diameter of the base tire at a maximum width location, and an outer diameter of the base tire at the bead portion, respec-tively, in the state that the base tire is in a free 2~ state filled with no internal pressure.
~ ccording to the present invention, since the outer diameter of the built tire is made appropriate relative to the mold for vulcanizing and shaping, occurrence of the buckling can significantly be prevented, and the ground-contacting shape of the recapped tire can be made uniform.
7 ,3 r~ 9 These and other objects, features and advantages of the invention will be appreciated upon reading of the following description of the inven~ion when taken in conjunction with the attached drawings, with the under-o~ standing that some modifications, variations and change~of the same could be made by the skilled person in the art to which the invention pertains without departi.ng from the spirit of the invention or the scope of claims appended hereto.
For a better understanding of the invention, reference is made to the attached drawings, wherein:
Fig. 1 is a sectional view of a built tire to which the present invention is applied;
Fig. 2~a) is a sectional diagram illustrating 1~ the dimension of a fourth cord-arrayed layer of a built tire in a non-restraint state;
Fig. 2(b) is a sectional diagram illustrating the dimension of the fourth cord-arrayed layer of the built tire inside a mold during a vulcanizing-shaping step;
Fig. 3(a) is a sectional view of a part of a bladder favorably applicable to the recapping process according to the present invention;
Fig. 3(b) is a schematic diagram showing the relationship between the radial growth of the base tire and the applied pressure;
~i7 ~ 1~
Fig. 45a) is a diagram showing the relationship between the elongation rate of the bladder shown in Fig. 3(a) in the circumferential direction and the number of times at which the bladder is expanded and o~ contracted by feeding and removing the internal pressure to the bladder;
Fig. 4(b) is a diayram showing the relationship between the radial expansion rate of the bladder shown in Fig. 3(a) and the average difference of radially grown amount between tread shoulders when the internal pressure of 0.5 kg/cm2 is applied to the bladder;
Fig, 5(a) is a sectional view illustrating holding rings to favorably cooperate with the bladder shown in Fig. 3(a): and 1~ Fig. 5(b) is a diagram showing the relationship between the outer diameter of the holding ring and the deviated amount of the center of the base tire.
Fig. 1 is a sectional view showing a raw tire 10 built by bonding two cord-arrayed layers and a un-vulcanized tread rubber onto a base tire having two cord-arrayed layers according to the present invention.
A carcas~ 12 includes a ply having cords radially arranged and toroidally extending between a pair of bead portions 14 spaced from each other in a rotary axis direction of the tire. Although it is illustrated that the carcass 12 of the built tire 10 has a single cord-2 ~ ~ 7 '~
arrayed layer, a plurality oE cord-arrayed layers may be used depending upon the specification of the tire.
In that case, at least one o the radial cord arrangement layers constituting the carcass is turned up around a bead core 16 of the bead portion 14 at each of the opposite ends.
Along the outer periphery of a crown portion of the carcass 12 are successively arranged four cord-arrayed layers 18, 20, 22 and 24 from the radially inner side to the radially outer side of the tire in this order, and these cord-arrayed layers form a belt 26.
The first cord-arrayed layer 18 is located on the radially inner side of the tire, and has a split structure in which a tire-widthwise central portion is 1~ removed over the circumferential direction of the tire.
Cords of the layer 18 are uniformly inclined upwardly in the right direction at a relatively small cross angle, for example, at a cross angle of 45-52, with respect to the the equatorial plane of the tire not shown.
The second cord-arrayed layer 20 is located adjacently on the radially outer side of the radially innermost cord-arrayed layer 18, and the cords of the layer 20 are uniformly inclined upwardly in the right direction at a relatively small cross angle, for example, at a cross angle of 18-20, with respect to the equatorial plane of the tire.
~ 3 The third cord-arrayed layer 22 is located adjacent to the second cord-arrayed layer 20, and the cords of the third layer 22 are inclined in a direction reverse to that of the cords of the second cord-arrayed 0~ layer 20 radially inwardly adjacent thereto, that is, inclined upwardly in the left direction, with respect to the equatorial plane of the tire. The angle defined by the cords of the third cord-arrayed layer and the tire equa~orial plane is in a range of 18-20 or in a range lower than this range.
In the fourth cord-arrayed layer 24 located on the radially outer side of the belt 26, the angle defined between the cords of the layer 24 and the tire equatorial plane is substantially equal to the cross 1~ angle defined by the cords of the third cord-arrayed layer and the tire equatorial plane, The built tire 10 is obtained by bonding an unvulcanized tread rubber 28 adjacent to and on the radially outer side of the belt 26. A recapped tire is obtained by applying an internal pressure into the built tire to press it against the inner surface of a given mold, and vulcanizing and shaping the built tire.
Different from the built tire 10 shown in Fig. 1, the inclined direction of the cords of each of the cord-26 arrayed layers constituting the belt 26 may be reversedor their inclined directions may be chan~ed to quite . .
: ' ' ', different ones.
Such a recapped tire may be obtained as follows:
First, a tread rubber of a tire to be recapped is removed by buffing, and then a base tire is obtained by removing third and fourth cord-arrayed layers located on the radially outer side of the tire along a line segment L denoted by a dot-and-dash line in Fig. 1 by using an appropriate cutter. A degree at which the tire is damaged is examined, and a base tire in which damage is not propagated into first and second coxd-arrayed layers 18 and lg located radially inside the tire is selected.
The surface shape and the dimension of the base tire are adjusted by using a wire brush or the like, an appropriate adhesive is applied to the resulting base tire, and a wide unvulcanized cushion sheet having a thickness of, for example, 0.5 mm - 1.0 mm is bonded thereto. By so doing, the excellent bonding between the remaining second cord-arrayed layer 20 and a third cord-arrayed layer 22 to be newly bonded can be assured.
When the width of the cushion sheet is greater than that of the below-mentioned third cord-arrayed layer 22, preferably substantially equal to that of the base tire, adhesion between the below-mentioned unvulcanized tread rubber and the brushed surface of the base tire can be improved.
In order to prevent separation of the third cord-arrayed layer 22 bonded onto the cushion sheet from an end, a narrow unvulcanl2ed cushion rubber (not shown) having a thickness of 0.5 ~ 0.8 mm is bonded, correspond-ing to each of widthwise end portions of the third cord-arrayed layer, between each of the widthwise end portions of the third cord-arrayed layer and the cushion sheet along the circumferential direction of the tire.
Next, the third cord-arrayed layer 22 is bonded to a given portion of the wide cushion sheet. The third cord-arrayed layer 22 is bonded onto the base tire such that the widthwise end portions of the layer 22 may be located on the cushion sheet.
Then, a new fourth cord-arrayed layer 24 is 1~ bonded adjacent the third cord-arrayed layer 22 and radially outwardly on the rentral portion of the layer 22. Finally, the built tire 10 is obtained by bonding a unvulcanized tread rubber adjacent 10 and on the radially outer side of the fourth cord-arrayed layer 24.
After the built tire 10 is placed in a given mold, the built tire is filled with an internal pressure, and vulcanized and shaped. According to the present invention, the Eollowing relationship of 0 S (B - Bo)/B
x 100 < 0.76 is satisfied. In these inequations, Bo is the outer diameter of the fourth cord-arrayed layer of the built tire to which no internal pressure i8 applied, ' ' ' .
as shown in Fig. 2(a), and B is the outer diameter of the fourth cord-arrayed layer 24 when the internal pressure is applied to the built tire, as shown in Fig. 2tb) when the raw tire is to be vulcanized and shaped in the mold.
As shown in Table shown below~ if (B - Bo)/B x 100 is less than zero, that is, if the outer diameter Bo of the built tire undertaking no restraint is greater than the inner diameter of the mold, the resulting recapped tire is buckled or the tread rubber enters between split faces of the mold. On the other hand, if ~B - Bo)/B x 100 is greater than 0.76, that is, if the built tire cannot be sufficiently pressed against the inner surface of the mold, sponge is formed in the tread of the recapped tire.
Table 1 _ _ (B-BU)/B x 100 Tire sectional shape _ ~
-0.1 buckled _ 0~0 good .... __ _ 0.4 good ", ._ 0.76 good 0.80 sponge formed 1.0 sponge formed 2~7~
In order that the built tire and the vulcanized and shaped tire, and particularly the fourth cord~
arrayed layer constituting the belt may satisfy the above-mentioned relationship, it is preferable to use a bladder which can swell the base tire for the formation of the built tire, while suppressing radial swelling of the base tire. One of such bladders is shown in Fig. 3.
Since the bladder is laterally substantially symmetrical with respect to the widthwise central portion, only a left half portion of the bladder is shown for simplicity.
As is the same with known bladders, the bladder 30 is made of a bag-shaped rubber or rubbery elastic member having flexibility, gas-tightness and heat 1~ resistance. The bladder is designed such that when the bladder is inflated with a pressurizin~ fluid, the thickness hl of a portion contacting the inner face of the crown of the base tire i9 greater than that h2 of the remainin~ portion, and the width ~ of the thicker ao portion of the bladder is greater than the width of that portion of the first cord-arrayed layer 18 constituting the belt which is removed from the layer 18, but smaller than the maximum width of the tire. A bladder body is supported by a support member 34.
a6 If the width e of the thicker portion of the bladder is smaller than the width of the central hollow ~ ^3 portion of the first cord-arrayed layer 18, the base tire is locally expanded radially outwardly at the central hollow portion as well as a portion near the hollow central portion. If the width e of the bladder is greater than the maximum width of the tire, it is likely that the bladder is more greatly swelled in the tire-radial direction then in the tire-width direction.
Rigidity of that thicker portion of the bladder 30 which is pressed against the inner surface of the crown portion of the base tire is higher as compared with that of the remaining portion of the bladder which contacts the other portion of the tire, such as sidewalls. Thus, the thicker portion of the bladder less greatly swells in the radially outer direction than lB in the widthwise outer direction, when the internal pressure is applied to the bladder. Accordin~ly, the bladder swells to substantially follow the shape of the inner surface of the base tire free from restraint.
That is, when the internal pressure is applied to the ao bladder, the belt portion remaining in the base tire is not greatly swelled in the radially outward direction.
Fig. 3(b) shows the radially outwardly swelled amount of a base tire when a pressurizing fluid was applied to each o~ a bladder having the structure shown a~ in Fig. 3~a), and a known bladder having a almost uniform thickness and a base tire in which the -~8-rl ~
pressurizing Eluid was directly applied without using any bladder.
On the o~her hand, since the bladder 30 i5 repeatedly expanded or contracted in the circumferential direction, following the feeding and discharging of the pressuri2ing fluid into the bladder, a ratio Sc of the diameter ED of the inner surface of the base tire in the free state to the outer diameter DB of the bladder in a free state not influenced by the internal pressure with the pressuring fluid is set at 240% or less.
As shown in Fig. 4(a), if the ratio i8 more than 240~, durability of the bladder 30 repeatedly subjected to the expansion and contraction is greatly reduced.
Preferably, the ratio 5c is not more than 190%. The l~ ratio Sc denotes a circumferential expandable degree following the feeding and discharging of the pressurizing fluid for the bladder.
Since the bladder 30 repeatedly radially expands and contracts, following the feeding and discharging of ~0 the pressurizing fluid, a ratio Sr of a value C, which is obtained by adding a total length of the radially inner surface in the radial section of the base tire to a value obtained by deducing the outer diameter D of the bladder from the diameter of the bead base portion, 2* relative to the width W of the bladder 30 is set at 110%
or more. As shown in Fig. 4(b), if the ratio Sr is less ~Y~7~
than 110%, the bladder is so great that the bladder cannot be appropriately inserted into the base tire to make centering alignment impossible, and the growth in the radius becomes dif~erent between the opposite tread o~ shoulders of the base tixe at locations spaced from the equatorial plane of the tire by 70 mm when the tire is inflated at an internal pressure of 0.5 kg/cm2.
Further, since the shape of the base -tire has been ordinarily deformed, different from an original shape of a fresh tire owing to use, it is advantageous that a part of a portion between the bead portion and at least the sidewall portion is held such that the base tire is uprightly held symmetrically with respect to the equatorial plane. Therefore, it is advantageous to use 1~ a member capable of holding the bead portion and the sidewall portion of the base tire from the exterior of the tire in a desired shape in cooperation with the bladder 30 inflated inside the base tire. For example, a pair of holding rings 36 shown in Fig. 5(a) is ~0 advantagèously used. In Fig. S(a), an imaginary line denotes the bladder in the contracted state.
The outer diameter d of the holding ring 36 is selected to satisfy the relationship: ~M - N)/2 x 0.65 < (d ~ N)/2 in which M and N are a diameter of the base a6 tire at a maximum width location before application of the internal pressure, and a diameter of the bead base portion of the base ~ire, respectively. As shown in Fig. 5(b), if [(d - N)/2]/[(M - N)/2]is less than 0.65, the center of the base tire is greatly deviated from a preset center.
o~ After the base tire is set by using the bladder 30 and the holding rings 36 as shown in Fig. 5(a~, the internal pressure to be applied to the bladder is appropriately selected so that the radially outermost cord-arrayed layer of the built tire formed may satisfy the inequations tl), and then a fresh cord-arrayed layer and an unvulcanized tread rubber are bonded to the base tire, thereby obtaining the built tire ~atisfyin~ the inequations (l).
As having been described before, according to 1~ the recapping process of the present invention, the recapped tire free from occurrence of buckling and entering of the tread rubber into the split faces of the mold when the tire is vulcanized and shaped in the mold can be obtained.
~B
Claims (7)
1. A process for recapping a pneumatic radial tire including a carcass toroidally extended between a pair of bead portions and composed of at least a ply having cords radially arranged, and a belt composed of three or more cord-arrayed layers arranged on a radially outer side of a crown portion of the carcass and having a split structure in which a central portion of a radially innermost cord-arrayed layer is removed, said process including the steps of obtaining a base tire by retaining two cord-arrayed layers positioned on a radially inner side of the tire and removing the other cord-arrayed layer or layers positioned radially outwardly from the radially inner two cord-arrayed layers as well as a tread rubber, bonding at least one cord-arrayed layer and a fresh tread rubber onto the base tire to built a built tire, applying an internal pressure into the built tire, and vulcanizing and shaping the built tire inside a mold, wherein a diameter (Bo) of the radially outermost cord-arrayed layer of the built tire before application of the internal pressure and a diameter (B) of the radially outmost cord-arrayed layer on the vulcanization and shaping inside the mold satisfy the following inequations:
O ? (B - Bo)/B X 100 ? 0.76.
O ? (B - Bo)/B X 100 ? 0.76.
2. The process according to Claim 1, wherein when the raw tire is formed, a bladder is used, which gives a smaller amount swelled radially outwardly on the application of the internal pressure as compared with an amount swelled axially outwardly.
3. The process according to Claim 2, wherein the bladder has that thickened central portion to be contacted with an inner surface of a crown portion of the base tire which is thicker than the remaining portion of the bladder.
4. The process according to Claim 3, wherein an axial width of the thickened central portion is greater than that of the central portion removed from the radially innermost cord-arrayed layer, but smaller than a maximum width of the tire.
5. The process according to Claim 2, wherein a ratio of an outer diameter of the bladder in a free state filled with no internal pressure to the diameter of the radially inner surface of the base rubber in a free state filled with no internal pressure is not more than 240%.
6. The process according to Claim 1, wherein a ratio of a sum of a total length of the radially inner surface in the radial section of the base tire and a value obtained by deducing the outer diameter of the bladder from the diameter of the bead base portion to the width of the bladder in a free state filled with no internal pressure is not less than 110%.
7. The process according to Claim 1, wherein the following inequation is satisfied: (M - N)/2 x 0.65 ? (d -D)/2 in which d is the outer diameter of each of holding rings which support the base tire at bead portions and sidewall portions of the base tire from axially outer sides, and M and N are a diameter of the base tire at a maximum width location, and an outer diameter of the base tire at the bead portion, respectively, in the state that the base tire is in a free state filled with no internal pressure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2417993A JPH0798367B2 (en) | 1990-12-14 | 1990-12-14 | Pneumatic radial tire rehabilitation method |
| JP2-417,993 | 1990-12-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2057579A1 true CA2057579A1 (en) | 1992-06-15 |
Family
ID=18525971
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2057579 Abandoned CA2057579A1 (en) | 1990-12-14 | 1991-12-13 | Process for recapping pneumatic radial tires |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH0798367B2 (en) |
| CA (1) | CA2057579A1 (en) |
| FR (1) | FR2670429B1 (en) |
| TR (1) | TR27370A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140007999A1 (en) * | 2011-02-22 | 2014-01-09 | Bridgestone Corporation | Tire |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1305117A (en) * | 1960-11-08 | 1962-09-28 | Kentredder Ltd | Method and apparatus for retreading tires |
| FR1333047A (en) * | 1961-09-08 | 1963-07-19 | Pirelli | Improvement in retreading of pneumatic casings for vehicles of all types |
| US3464873A (en) * | 1966-03-23 | 1969-09-02 | Hawkinson Paul E Co | Method of treading pneumatic tire casings |
| US4218277A (en) * | 1975-12-17 | 1980-08-19 | Der Burg Sjirk Van | Tire retreading method including adding reinforcing belt |
| GB1601100A (en) * | 1977-03-28 | 1981-10-21 | Goodyear Tire & Rubber | Method of building a radial tyre |
| US4258776A (en) * | 1979-01-29 | 1981-03-31 | The Goodyear Tire & Rubber Company | Retreaded tire, method and apparatus |
| JPS5816839A (en) * | 1981-07-24 | 1983-01-31 | Sumitomo Rubber Ind Ltd | Method of vulcanizing elastomer product |
| JPS61290041A (en) * | 1985-06-17 | 1986-12-20 | Toyo Tire & Rubber Co Ltd | Manufacture of reclaimed tire having steel belt |
| JPS62267107A (en) * | 1986-05-16 | 1987-11-19 | Yokohama Rubber Co Ltd:The | Method for curing tire |
-
1990
- 1990-12-14 JP JP2417993A patent/JPH0798367B2/en not_active Expired - Lifetime
-
1991
- 1991-12-12 FR FR9115456A patent/FR2670429B1/en not_active Expired - Fee Related
- 1991-12-12 TR TR01172/91A patent/TR27370A/en unknown
- 1991-12-13 CA CA 2057579 patent/CA2057579A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| FR2670429A1 (en) | 1992-06-19 |
| JPH0798367B2 (en) | 1995-10-25 |
| FR2670429B1 (en) | 1997-08-14 |
| TR27370A (en) | 1995-01-17 |
| JPH04216035A (en) | 1992-08-06 |
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