CA1136811A - Apparatus for producing pneumatic tires - Google Patents
Apparatus for producing pneumatic tiresInfo
- Publication number
- CA1136811A CA1136811A CA000362302A CA362302A CA1136811A CA 1136811 A CA1136811 A CA 1136811A CA 000362302 A CA000362302 A CA 000362302A CA 362302 A CA362302 A CA 362302A CA 1136811 A CA1136811 A CA 1136811A
- Authority
- CA
- Canada
- Prior art keywords
- tire
- cords
- mold
- portions
- mold element
- 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.)
- Expired
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)
- B29D30/0601—Vulcanising tyres; Vulcanising presses for tyres
- B29D30/0661—Rigid cores therefor, e.g. annular or substantially toroidal cores
-
- 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)
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Tyre Moulding (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A cavity having the shape of the tire to be produced is defined by a mold comprising an upper element, a lower element and a core element which are fittable to and releasable from one another. The core mold element comprises three divided segments, i.e., a segment for forming the inner surface of the tire tread, and a pair of segments for forming the inner surfaces of the tire sidewalls including tire beads. The core mold element has two pairs of nipping portions for holding the opposite ends of tire cords placed on the tread inner surface forming segment. The nipping portions in each pair are movable toward or away from each other. The tire cords nipped at their opposite ends by the core mold element are held in place within the cavity by the cooperation of the upper and lower mold elements, and a molding material composed of rubber or an equivalently elastic material is filled into the cavity and cured.
A cavity having the shape of the tire to be produced is defined by a mold comprising an upper element, a lower element and a core element which are fittable to and releasable from one another. The core mold element comprises three divided segments, i.e., a segment for forming the inner surface of the tire tread, and a pair of segments for forming the inner surfaces of the tire sidewalls including tire beads. The core mold element has two pairs of nipping portions for holding the opposite ends of tire cords placed on the tread inner surface forming segment. The nipping portions in each pair are movable toward or away from each other. The tire cords nipped at their opposite ends by the core mold element are held in place within the cavity by the cooperation of the upper and lower mold elements, and a molding material composed of rubber or an equivalently elastic material is filled into the cavity and cured.
Description
113f~
TIT~E OF THE INVEN~ION
APPARATUS FOR PRODUCING PNE~ATIC TIRES
~ACKGROUND OF ~HE I~ENTION
Pneumatic tires for vehicles adapted to be driven in various areas including desert, wet land, waste land, etc. advantageously have high flexibility, a large ground contact area so as to have sufficient load-carrying capacity and trac-tion for running in such areas and an inflation pressure of about 0.1 to 0.3 kg/cm2 in order to run at a low ground contact pressure.
Accordingly cordless tires made only of rubber or equivalently elastic material and capable of retaining a low pressure are preferable as pneumatic tires, especially as tubeless pneumatic tires, for such vehicles.
However, cordless tires are very ~usceptible to puncuture when the tread strikes nails, ~lass pieces and other sharp obstacles on the road surface.
Particularly tubeless pneumatic tires for vehicles to be driven in various areas are more prone to puncture because of varying driving environments.
While pneumatic tires are adapted to mitigate shocks by the deformation of the tread during travel, shock impact, when acting thereon, deforms the tire and also gives the tire an increased inflation pressure, whioh ~13~
acts to reduce the deformation and the absor~tion of the impact.
The reduction in the voll~e of the deformed portion of the tire due to the deformation is balanced by bulging deformation of another p~rtion of the sealed interior of the tire, or by an increase in the inflation pressure.
As means for rendering tires less susceptible to puncture, tire co-rds are incorporated in tubeless pneumatic tires which are made entirely of rubber or equivalently elastic material.
~ ,~lith such tubeless pneumatic tires havin~
cords incorporated therein, the cords extend from one bead of the tire to the other bead, with the opposite ends of the cords substantially secured to the beads.
The inflation pressure of the tire acts on the cords and is ultimately supported by the beads.
When the tire cords have a low elongation and extend from bead to bead as fixed ~hereto, the varia-tion in the interior volume of the tire due to deforma-tion is balanced to a greater extent by the increase of the inflation pressure of the tire than by the bulging deformation of the interior of the tire which is restrained by the cords. This greatly reduces the absorption of impact. Although outstanding in endurance against - : : -, ' 113~
p~mct~lre, the tire does not have flexiblity sufficient for use in ~ehicles for travellin_ in various areas, rendering such vehicles seriousl~- uncomfortable to ride.
It has therefore been desired to provide tubeless pneumatic tires which have hi~h cushionin~
ability, sufficient flexibility and outstanding resistance to puncture and which are especially suited for use in vehicles of the type described above. We have already succeeded in developing such tires which have the following improved construction.
The tubeless pneumatic tire of improved construction is made entirely of rubber or equivalently elastic material and has incorporated therein tire cords provided along the inner periphery of the tire and having opposite ends which are not fixedly attached to the beads. While the tire cords give the tread resistance to puncture, an elastic deformable portion composed substantially of rubber or equivalently elastic material is formed between the ends of the cords on each side of the tire and the corresponding bead. With this construction, the rise of inflation pressure is inhibited to a ~reater extend to afford improved cushioning ability and an extremely comfortable ride.
The tubeless pneumatic tire of such improved construction is produced by a mold comprising at least 113~
three co~ponents, namely an upper mold element, a lower mold element and a core mold element, defining a ca~ity having the shape of the tire. However, when rubber or like elastic material is charged into the cavity for molding, the flow of the material acts on the tire cords which are not secured at their ends to the bead portions, consequently disturbing the arran~ement of the tire cords and causing movement of cords. Thus diIficulties are encountered in accurately positioning the cord ends, with the inevitable result that the tire cords will not be arranged uniformly in the tire obtained.
Although the tire cords are usually placed on the core mold element in accurate position before the cavity is filled with the moldin~ material, the cords, which are arranged in a toroidal annular form in conformity with the shape of the tire inner surface, are difficult to place in position. Additionally, if accurately positioned, the cords will be displaced by the flow of the molding material.
SI~ARY OF THE INVENTIO~
The present invention relates to an apparatus for producing pneumatic tires, and more particularl~ to an apparatus for producing pneumatic tires of improved construction with divided mold elements which tires are 1:13f~
capable of retaining a relatively low infl~ltion pressure, have incor~orated therein tire cords arranged along the inner periphery of -the tire tread, include a substantially elastic deformable portion between -the ends of the cords and the bead on each side of the tire, are well-suited for use in vehicles adapted to be driven in various areas.
The invention provides an apparatus for producing pneumatic tires comprising at least three fittable mold components, i.e., an upper mold element, a lower mold element and a core mold element. The core mold element comprises at least three divided fittable mold segments for forming the inner surfaces of the tire tread and the tire sidewalls including a pair of beads. The tread inner surPace forming mold segment and at least one of the sidewall inner surface forming mold segments have on their opposed faces nipping portions movable toward or away from each other for holding at least one end of each ~ ti~e cord~.
An object of the present invention is to provide an apparatus of the above construction for producing pneumatic tires in which the nipping portions are adapted to hold at least one end of each cord placed on the outer peripheral surface of the core mold element so that the cords will not be disturbed by the flow of 113~
the molding material charged into the cavity, permitting -the curing of the moldin~ material with the cord ends accurately held in position.
Another object of the invention is to provide an apparatus of the construction described above for producing pneumatic tires in which thc tread inner surface forming mold ~egment is formed on its outer peripheral surface with indentations and projections, with the nipping portions adapted to hold at least one end of each of the tire cords in position, so that the stretch of the cords due to the flow o~ the molding material can be accommodated by the indentations and projections when the cavity is filled with the molding material with the cords thus held in position.
Another object of the invention is to provide an apparatus of the type described above for producing pneumatic tires in which two pairs of nipping portions are disposed symmetrically with respect to the equatorial line of the tire for holding the opposite ends of the tire cords, the nipping portions in each pair being movable toward or away from each other, so that the tire cords can be arranged uniformly on the outer peripheral surface of the core mold element.
Another object of the invention is to provide an apparatus of the construction descri~ed in the third ~ ' 113~
ob,ject above in which one of the nip~ing portlons in each pair has an annular recess for accommodating therein the corresponding end of each of the tire cords in a curled form and substantially enclosing the curled end in a molded portion of the molding ma,terial, so that the opposite cord ends will be disposed in annular pro~ections which are to be positioned near the shoulders of the tire and symmetrically with respect to the equatorial line and to be formed on the inner surface of the tire along a circumference centered about the axis of rotation of the tire.
Still another object of the inventi.on is to provide an apparatus of the type described above for producing pneumatic tires in which the tire cords can be easily placed in position on the outer periphery of the core mold segment and by which annular grooves can be formed in the inner surface of the tire symmetrically in corresponding relation to the beads of the tire, the tire being easily releasable from the apparatus upon molding.
BRIEF DESCRIPTIO~ OF ~HE DRAWINGS
Figs. 1 to 5 are sectional views schematlcally showing a first embodiment of the invention and also illustrating tire molding steps;
1136~11 Figs. 1 to ~ are sectional views showing the movement of segments of ~. core mold element;
~ ig. 4 is a sectional view showing an up~er mold element, a lower mold element a.nd the core mold element;
Fig. 5 is a sectional view showing the embodi-ment during molding operation;
~ ig. 6 is a fragmentary enlarged view in section showing the core mold element of the first embodiment;
Figs. 7 (1) and (2) are sectional views schematically showing tire cord end nipping portions:
~ ig. 8 is a plan view schematically showing tire cords arranged in place;
Fig. 9 is a sectional view schematically showing a second embodiment of the invention during molding operation;
~ ig. 10 is a fragmentary enlarged view in section showing the core mold element of the second embodiment;
Figs. 11 (1) and (2) are fra~mentary di.agrams showing two examples of projections and indentations formed on the tread inner surface forming core mold segment of the second embodiment;
~ig. 12 is a. sectional view schematically - :' .: :
~36~11 showing a third embodiment of the invention durin~
moldin~ operation; and ~ igs. 13, 14 and 15 are sectional views sho~in~
three tires as fitted to rims.
DESCRIP~ION Ol~ THE PRR~ERRED ENT:130DIMENTS
A first embodiment of the invention vJill be described with reference to ~`igs. 1 to 5 which also schematically show the steps of producing tires.
A tire mold 1 comprises at least three fittable components, i.e., an upper mold element 2, a lower mold element 3 and a core mold element 4, which coact to define a cavity 5 having the shape of the tire to be manufactured. The cavity 5, which is shown in section in ~i'ig. 5, extends continuously along the equatorial line of the tire in the form of a ring.
The core mold element 4 com~rises at least three mold segments which are fittable together, i.e., a mold segment 6 for forming the inner surface of the tire -tread, and a pair of mold segments 7 and 8 for forming the inner surfaces of tire sidewalls including the beads.
'Nhen clamped, these divided segments are fitted together to form the inner surface of the tread, the inner surfaces of tire shoulder portions and -the inner surfaces of the sidewalls including the beads.
113~
~ 'he up~er mold segmen-t 7 and ihe lower rnold segment 8 of the core mold element 4 are openably divided along a horizontal plane. The mold segment 6 for the tread is divided from the segments 7 and 8 along a vertical pla1le extendin~ through the shoulders of the tire to be made. The seg~ent 6 is fi-tted to the upper segment 7 by engaging means 9 and is vertically movable rclative to the se~ment 7.
The lower se~nent 8 is movable upward and downward by the stroke of an unillustrated cylinder device disposed at the center of -the rnolding a~paratus.
When the segments are clamped together, the whole core mold element 4 is movable upward and downward by the cylinder device relative to the upper mold element 2 which is stationary.
~ 'urthermore, the lower mold element 3 is movable u-pward and downward rel~tive to the stationary upper mold element 2 by the stroke of an unillustrated cylinder device. In this way, the upper, lower and core mold elements 2, 3, 4 can be clamped together for molding and released from one another for the removal of -the molded tire.
The up er and lower mold elements 2, 3 for defining the external shape and size of the tire are formed on their inner surfaces with portions lO, ll for forming , .
' ` : ' ' .
:, 113~
the tread. pattern of the tire. These elem~nts are also formed on their inner surfaces with portions 12, 13 for forming the outer su.rfaces of the tire sidewalls including the shoulders and beads. As seen in ~'igs. 4 and 5, means 15 for feeding a block of molding material, namely rubber or an equivalently elastic material, extends circumferentially along the junction between the upper an~ lower mold elements 2, 3. -The core mold element 4 comprising at least three fittable segments has portions for nipping theends of tire cords. According to the first embodiment shown in ~'ig. 3, the upper and lower end faces 16, 17 of the tread inner surface forming mold segment 6 are substantially opposed respectively to the end faces 18, 19 of the mold segments 7, 8 for forming the inner surfaces of the sidewalls. The end faces 16, 1~ provide upper nipping portions 20 which are movable toward or away from each other. The end faces 17, 19 serve as lower nipping portions 21 which are sirnilarly rnovable.
The upper and lower nipping portions 20, 21 are positioned at the tire shoulders and extend centripetally o~ -the tire.
As seen in L~'ig. 6, curved recesses 23, 24 extending circumferentially are formed at the upper and lower nipping portions 20, 21, that is, substantially in 113~811 the end :t`aces 1~, 19 respectivel~y.
i~`u.~ther as shown in l~`igs. 6 and 7 (1) and (2), the upper nipping ~ortions 20 have a curved recess 25 extending circumf`erentially and disosed at a location 5 radially inward from the outer peri~hery of the core element 4. lhe recess 25 is adapted to accommodate the ends 22B of tire cords in a Xolded forr.~ as seen in ~'ig.
7 (2). The molding material, when par-tly f'lowing into the recess 25 and cured, encloses the folded cord ends 22B therein to protect the cords f`rom breaking. l~'urther as best seen in Figs. 7 (1) and (2), the curved outer surface of the sidewall forming segment 7 is stepped inward from the tread forming segment 6 at the upper nipping portions 20 as indicated at a, whereby a bearing wall 23A is formed on the segment 7. When tire cords 22 are wound on the tread forming segment 6 with their ends 23B nipped in place and the molding material is charged into the cavity for molding, the f`low of the material will s-tretch th.e cords 22, but the stretched portions of the cords bear against the wall 23A and are allowed to move radially into the core element ~-with ease.
Examples of useful materials for the tire cord 22 are those having a small elongation, such as nylon, polyester, rayon and other synthetic or artif'icial 1~3~
l`ibers, natural fibers, and steel,alumin~ and like metals.
5uch materials may be used in combinatlon. Such materials are used in the f`orm of monofilaments, tapes, loosely arranged yarns or a thick fibric. These materials may be used as coated with an uncured or semicured material which is the same as the molding material or compatible therewith.
The tire cords 22 are applied to the outer periphery of the mold segment 6 with one end 22A of each cord first held between the lower nipping portions 21 as seen in ~`ig. 3, and the other ends 22B oft~e cords are thereafter held by the ni~ping portions 20. q'he cords 22 are wound on the se~nent 6 in the usual manner.
When the weft elements of the tire cords 22 are placed at an angle 0 of 0 to 15 degrees with respect to the equator 0-0 of the tire as seen in ~ig. 8, the resul-ting tire will assure a comfortable ride. When the tire needs to have high rigidity and load-bearing capacity, the angle 0 may be 50 degrees, for e~ample.
Since the ends 22A of the cords 22 are f`irst held betwéen the lower nipping portions 21, and the remaining portions of the cords are then wound on the mold segrnent 6 transversly thereof as indicated at A in l~ig. 6 over the entire circumference of the segrnent 6, the angle a of the lower nipping PortLons 21 is 10 to ' 113~8i~1 45 degrees as shown in ~'ig. 6 to ~revent the ends 22A lror.
sli~?ping off and to assure trouble-lree applicatlon of the cords 22. The uPper ni-pping portions 20 have an angle ~ of 30 to 90 degrees to render the other ends 22B
smoothly holdable by the por-tions 20.
The curved upper and lower corners of the mold segment 6 have a radius R of 3 to 8 mm as exemplified in I1`iga. 7 (1) and (2) for the upper end face 16.
To prevent the doughnut-shaped cord arrangement from contraction and excessive expansion that would lead to the loosening and rupture of cords, the cords 22 have a length d which is smaller than the peripheral length D of the segment 6. Preferably 0.9 ~ d~D > 0.7.
With reference chiefly to ri'igs. 1 to 5, the operation of the first embodiment will be described below for the production of tubeless pneumatic tires.
Before tire cords 22 are wound on the core mold element 4, the mold segments 6 to 8 are in the fitted position as seen in Ii'ig. 1.
To wind tire cords 22 on the segment 6, the lower mold segment 8 is mo~ed down by a stroke of an unillustrated cylinder device as seen in Fig. 2. Since the segment 6 is fitted to the lower segment 8 and also to the upper segment 7 by the engaging means 9, the segment 6 moves down with the ower segment 8 within the -; -.
~3~81~
range allowed by -the engaging means 9 to open the upper nipping portlons 20 as seen in l~lig. 2.
'~'ihen the lower segment 8 is further lowered, the lower nipping portions 21 are opened as shown in I~'ig. 3 since the segment 6 i5 now held to the upper segment 7 by the engaging means 9.
With the upper and lower nipping portions 20, 21 thus opened, the ends 22A of tire cords 22 are placed between the lower nipping portions 21 manually or by a cord applicator of the known -type ~not shown). The lower segment 8 is then raised by the cylinder device to close the lower nipping portions 21. Thus the end faces 17, 19 coact to hold the ends 22A.
The remaining portions of the cords 22 are thereafter wound on -the mold segment 6 over its outer periphery by the applicator or manually. '~ith the other ends 22B released from the applicator and stretched as shown in ~1ig. 7 (1), both the lower segment 8 and the segment 6 are raised by the cylinder device to fit them to the upper segment 7, whereby the end faces 16, 18 serving as the upper nipping portions 20 coact to hold the ends 22B.
In this way, the tire cords are wound on the tread inner surface forming mold segment 6 OI` the core element 4, with their opposite ends 22A, 22B fixedly 113~
held by the u~per and lower nipping ~ortions 20, 21.
The clamping force applied at this time is preferably at least 1 kg ~er cord.
After the tire cords 22 have been held in place on the outer periphery of the core element 4, the element 4 is raised in its entirety by the cylinder device to ~roper -position rela-tive to the stationary upper mold element 2, and -the lower mold element 3 is also raised by an unillustrated cylinder device. At this -tlme, a molding material comprising rubber or an e~uivalently elastic material and in the ~orm of an annular block 14 is placed on the f`eeding means 15 at :the junction between the upper and lower mold elements
TIT~E OF THE INVEN~ION
APPARATUS FOR PRODUCING PNE~ATIC TIRES
~ACKGROUND OF ~HE I~ENTION
Pneumatic tires for vehicles adapted to be driven in various areas including desert, wet land, waste land, etc. advantageously have high flexibility, a large ground contact area so as to have sufficient load-carrying capacity and trac-tion for running in such areas and an inflation pressure of about 0.1 to 0.3 kg/cm2 in order to run at a low ground contact pressure.
Accordingly cordless tires made only of rubber or equivalently elastic material and capable of retaining a low pressure are preferable as pneumatic tires, especially as tubeless pneumatic tires, for such vehicles.
However, cordless tires are very ~usceptible to puncuture when the tread strikes nails, ~lass pieces and other sharp obstacles on the road surface.
Particularly tubeless pneumatic tires for vehicles to be driven in various areas are more prone to puncture because of varying driving environments.
While pneumatic tires are adapted to mitigate shocks by the deformation of the tread during travel, shock impact, when acting thereon, deforms the tire and also gives the tire an increased inflation pressure, whioh ~13~
acts to reduce the deformation and the absor~tion of the impact.
The reduction in the voll~e of the deformed portion of the tire due to the deformation is balanced by bulging deformation of another p~rtion of the sealed interior of the tire, or by an increase in the inflation pressure.
As means for rendering tires less susceptible to puncture, tire co-rds are incorporated in tubeless pneumatic tires which are made entirely of rubber or equivalently elastic material.
~ ,~lith such tubeless pneumatic tires havin~
cords incorporated therein, the cords extend from one bead of the tire to the other bead, with the opposite ends of the cords substantially secured to the beads.
The inflation pressure of the tire acts on the cords and is ultimately supported by the beads.
When the tire cords have a low elongation and extend from bead to bead as fixed ~hereto, the varia-tion in the interior volume of the tire due to deforma-tion is balanced to a greater extent by the increase of the inflation pressure of the tire than by the bulging deformation of the interior of the tire which is restrained by the cords. This greatly reduces the absorption of impact. Although outstanding in endurance against - : : -, ' 113~
p~mct~lre, the tire does not have flexiblity sufficient for use in ~ehicles for travellin_ in various areas, rendering such vehicles seriousl~- uncomfortable to ride.
It has therefore been desired to provide tubeless pneumatic tires which have hi~h cushionin~
ability, sufficient flexibility and outstanding resistance to puncture and which are especially suited for use in vehicles of the type described above. We have already succeeded in developing such tires which have the following improved construction.
The tubeless pneumatic tire of improved construction is made entirely of rubber or equivalently elastic material and has incorporated therein tire cords provided along the inner periphery of the tire and having opposite ends which are not fixedly attached to the beads. While the tire cords give the tread resistance to puncture, an elastic deformable portion composed substantially of rubber or equivalently elastic material is formed between the ends of the cords on each side of the tire and the corresponding bead. With this construction, the rise of inflation pressure is inhibited to a ~reater extend to afford improved cushioning ability and an extremely comfortable ride.
The tubeless pneumatic tire of such improved construction is produced by a mold comprising at least 113~
three co~ponents, namely an upper mold element, a lower mold element and a core mold element, defining a ca~ity having the shape of the tire. However, when rubber or like elastic material is charged into the cavity for molding, the flow of the material acts on the tire cords which are not secured at their ends to the bead portions, consequently disturbing the arran~ement of the tire cords and causing movement of cords. Thus diIficulties are encountered in accurately positioning the cord ends, with the inevitable result that the tire cords will not be arranged uniformly in the tire obtained.
Although the tire cords are usually placed on the core mold element in accurate position before the cavity is filled with the moldin~ material, the cords, which are arranged in a toroidal annular form in conformity with the shape of the tire inner surface, are difficult to place in position. Additionally, if accurately positioned, the cords will be displaced by the flow of the molding material.
SI~ARY OF THE INVENTIO~
The present invention relates to an apparatus for producing pneumatic tires, and more particularl~ to an apparatus for producing pneumatic tires of improved construction with divided mold elements which tires are 1:13f~
capable of retaining a relatively low infl~ltion pressure, have incor~orated therein tire cords arranged along the inner periphery of -the tire tread, include a substantially elastic deformable portion between -the ends of the cords and the bead on each side of the tire, are well-suited for use in vehicles adapted to be driven in various areas.
The invention provides an apparatus for producing pneumatic tires comprising at least three fittable mold components, i.e., an upper mold element, a lower mold element and a core mold element. The core mold element comprises at least three divided fittable mold segments for forming the inner surfaces of the tire tread and the tire sidewalls including a pair of beads. The tread inner surPace forming mold segment and at least one of the sidewall inner surface forming mold segments have on their opposed faces nipping portions movable toward or away from each other for holding at least one end of each ~ ti~e cord~.
An object of the present invention is to provide an apparatus of the above construction for producing pneumatic tires in which the nipping portions are adapted to hold at least one end of each cord placed on the outer peripheral surface of the core mold element so that the cords will not be disturbed by the flow of 113~
the molding material charged into the cavity, permitting -the curing of the moldin~ material with the cord ends accurately held in position.
Another object of the invention is to provide an apparatus of the construction described above for producing pneumatic tires in which thc tread inner surface forming mold ~egment is formed on its outer peripheral surface with indentations and projections, with the nipping portions adapted to hold at least one end of each of the tire cords in position, so that the stretch of the cords due to the flow o~ the molding material can be accommodated by the indentations and projections when the cavity is filled with the molding material with the cords thus held in position.
Another object of the invention is to provide an apparatus of the type described above for producing pneumatic tires in which two pairs of nipping portions are disposed symmetrically with respect to the equatorial line of the tire for holding the opposite ends of the tire cords, the nipping portions in each pair being movable toward or away from each other, so that the tire cords can be arranged uniformly on the outer peripheral surface of the core mold element.
Another object of the invention is to provide an apparatus of the construction descri~ed in the third ~ ' 113~
ob,ject above in which one of the nip~ing portlons in each pair has an annular recess for accommodating therein the corresponding end of each of the tire cords in a curled form and substantially enclosing the curled end in a molded portion of the molding ma,terial, so that the opposite cord ends will be disposed in annular pro~ections which are to be positioned near the shoulders of the tire and symmetrically with respect to the equatorial line and to be formed on the inner surface of the tire along a circumference centered about the axis of rotation of the tire.
Still another object of the inventi.on is to provide an apparatus of the type described above for producing pneumatic tires in which the tire cords can be easily placed in position on the outer periphery of the core mold segment and by which annular grooves can be formed in the inner surface of the tire symmetrically in corresponding relation to the beads of the tire, the tire being easily releasable from the apparatus upon molding.
BRIEF DESCRIPTIO~ OF ~HE DRAWINGS
Figs. 1 to 5 are sectional views schematlcally showing a first embodiment of the invention and also illustrating tire molding steps;
1136~11 Figs. 1 to ~ are sectional views showing the movement of segments of ~. core mold element;
~ ig. 4 is a sectional view showing an up~er mold element, a lower mold element a.nd the core mold element;
Fig. 5 is a sectional view showing the embodi-ment during molding operation;
~ ig. 6 is a fragmentary enlarged view in section showing the core mold element of the first embodiment;
Figs. 7 (1) and (2) are sectional views schematically showing tire cord end nipping portions:
~ ig. 8 is a plan view schematically showing tire cords arranged in place;
Fig. 9 is a sectional view schematically showing a second embodiment of the invention during molding operation;
~ ig. 10 is a fragmentary enlarged view in section showing the core mold element of the second embodiment;
Figs. 11 (1) and (2) are fra~mentary di.agrams showing two examples of projections and indentations formed on the tread inner surface forming core mold segment of the second embodiment;
~ig. 12 is a. sectional view schematically - :' .: :
~36~11 showing a third embodiment of the invention durin~
moldin~ operation; and ~ igs. 13, 14 and 15 are sectional views sho~in~
three tires as fitted to rims.
DESCRIP~ION Ol~ THE PRR~ERRED ENT:130DIMENTS
A first embodiment of the invention vJill be described with reference to ~`igs. 1 to 5 which also schematically show the steps of producing tires.
A tire mold 1 comprises at least three fittable components, i.e., an upper mold element 2, a lower mold element 3 and a core mold element 4, which coact to define a cavity 5 having the shape of the tire to be manufactured. The cavity 5, which is shown in section in ~i'ig. 5, extends continuously along the equatorial line of the tire in the form of a ring.
The core mold element 4 com~rises at least three mold segments which are fittable together, i.e., a mold segment 6 for forming the inner surface of the tire -tread, and a pair of mold segments 7 and 8 for forming the inner surfaces of tire sidewalls including the beads.
'Nhen clamped, these divided segments are fitted together to form the inner surface of the tread, the inner surfaces of tire shoulder portions and -the inner surfaces of the sidewalls including the beads.
113~
~ 'he up~er mold segmen-t 7 and ihe lower rnold segment 8 of the core mold element 4 are openably divided along a horizontal plane. The mold segment 6 for the tread is divided from the segments 7 and 8 along a vertical pla1le extendin~ through the shoulders of the tire to be made. The seg~ent 6 is fi-tted to the upper segment 7 by engaging means 9 and is vertically movable rclative to the se~ment 7.
The lower se~nent 8 is movable upward and downward by the stroke of an unillustrated cylinder device disposed at the center of -the rnolding a~paratus.
When the segments are clamped together, the whole core mold element 4 is movable upward and downward by the cylinder device relative to the upper mold element 2 which is stationary.
~ 'urthermore, the lower mold element 3 is movable u-pward and downward rel~tive to the stationary upper mold element 2 by the stroke of an unillustrated cylinder device. In this way, the upper, lower and core mold elements 2, 3, 4 can be clamped together for molding and released from one another for the removal of -the molded tire.
The up er and lower mold elements 2, 3 for defining the external shape and size of the tire are formed on their inner surfaces with portions lO, ll for forming , .
' ` : ' ' .
:, 113~
the tread. pattern of the tire. These elem~nts are also formed on their inner surfaces with portions 12, 13 for forming the outer su.rfaces of the tire sidewalls including the shoulders and beads. As seen in ~'igs. 4 and 5, means 15 for feeding a block of molding material, namely rubber or an equivalently elastic material, extends circumferentially along the junction between the upper an~ lower mold elements 2, 3. -The core mold element 4 comprising at least three fittable segments has portions for nipping theends of tire cords. According to the first embodiment shown in ~'ig. 3, the upper and lower end faces 16, 17 of the tread inner surface forming mold segment 6 are substantially opposed respectively to the end faces 18, 19 of the mold segments 7, 8 for forming the inner surfaces of the sidewalls. The end faces 16, 1~ provide upper nipping portions 20 which are movable toward or away from each other. The end faces 17, 19 serve as lower nipping portions 21 which are sirnilarly rnovable.
The upper and lower nipping portions 20, 21 are positioned at the tire shoulders and extend centripetally o~ -the tire.
As seen in L~'ig. 6, curved recesses 23, 24 extending circumferentially are formed at the upper and lower nipping portions 20, 21, that is, substantially in 113~811 the end :t`aces 1~, 19 respectivel~y.
i~`u.~ther as shown in l~`igs. 6 and 7 (1) and (2), the upper nipping ~ortions 20 have a curved recess 25 extending circumf`erentially and disosed at a location 5 radially inward from the outer peri~hery of the core element 4. lhe recess 25 is adapted to accommodate the ends 22B of tire cords in a Xolded forr.~ as seen in ~'ig.
7 (2). The molding material, when par-tly f'lowing into the recess 25 and cured, encloses the folded cord ends 22B therein to protect the cords f`rom breaking. l~'urther as best seen in Figs. 7 (1) and (2), the curved outer surface of the sidewall forming segment 7 is stepped inward from the tread forming segment 6 at the upper nipping portions 20 as indicated at a, whereby a bearing wall 23A is formed on the segment 7. When tire cords 22 are wound on the tread forming segment 6 with their ends 23B nipped in place and the molding material is charged into the cavity for molding, the f`low of the material will s-tretch th.e cords 22, but the stretched portions of the cords bear against the wall 23A and are allowed to move radially into the core element ~-with ease.
Examples of useful materials for the tire cord 22 are those having a small elongation, such as nylon, polyester, rayon and other synthetic or artif'icial 1~3~
l`ibers, natural fibers, and steel,alumin~ and like metals.
5uch materials may be used in combinatlon. Such materials are used in the f`orm of monofilaments, tapes, loosely arranged yarns or a thick fibric. These materials may be used as coated with an uncured or semicured material which is the same as the molding material or compatible therewith.
The tire cords 22 are applied to the outer periphery of the mold segment 6 with one end 22A of each cord first held between the lower nipping portions 21 as seen in ~`ig. 3, and the other ends 22B oft~e cords are thereafter held by the ni~ping portions 20. q'he cords 22 are wound on the se~nent 6 in the usual manner.
When the weft elements of the tire cords 22 are placed at an angle 0 of 0 to 15 degrees with respect to the equator 0-0 of the tire as seen in ~ig. 8, the resul-ting tire will assure a comfortable ride. When the tire needs to have high rigidity and load-bearing capacity, the angle 0 may be 50 degrees, for e~ample.
Since the ends 22A of the cords 22 are f`irst held betwéen the lower nipping portions 21, and the remaining portions of the cords are then wound on the mold segrnent 6 transversly thereof as indicated at A in l~ig. 6 over the entire circumference of the segrnent 6, the angle a of the lower nipping PortLons 21 is 10 to ' 113~8i~1 45 degrees as shown in ~'ig. 6 to ~revent the ends 22A lror.
sli~?ping off and to assure trouble-lree applicatlon of the cords 22. The uPper ni-pping portions 20 have an angle ~ of 30 to 90 degrees to render the other ends 22B
smoothly holdable by the por-tions 20.
The curved upper and lower corners of the mold segment 6 have a radius R of 3 to 8 mm as exemplified in I1`iga. 7 (1) and (2) for the upper end face 16.
To prevent the doughnut-shaped cord arrangement from contraction and excessive expansion that would lead to the loosening and rupture of cords, the cords 22 have a length d which is smaller than the peripheral length D of the segment 6. Preferably 0.9 ~ d~D > 0.7.
With reference chiefly to ri'igs. 1 to 5, the operation of the first embodiment will be described below for the production of tubeless pneumatic tires.
Before tire cords 22 are wound on the core mold element 4, the mold segments 6 to 8 are in the fitted position as seen in Ii'ig. 1.
To wind tire cords 22 on the segment 6, the lower mold segment 8 is mo~ed down by a stroke of an unillustrated cylinder device as seen in Fig. 2. Since the segment 6 is fitted to the lower segment 8 and also to the upper segment 7 by the engaging means 9, the segment 6 moves down with the ower segment 8 within the -; -.
~3~81~
range allowed by -the engaging means 9 to open the upper nipping portlons 20 as seen in l~lig. 2.
'~'ihen the lower segment 8 is further lowered, the lower nipping portions 21 are opened as shown in I~'ig. 3 since the segment 6 i5 now held to the upper segment 7 by the engaging means 9.
With the upper and lower nipping portions 20, 21 thus opened, the ends 22A of tire cords 22 are placed between the lower nipping portions 21 manually or by a cord applicator of the known -type ~not shown). The lower segment 8 is then raised by the cylinder device to close the lower nipping portions 21. Thus the end faces 17, 19 coact to hold the ends 22A.
The remaining portions of the cords 22 are thereafter wound on -the mold segment 6 over its outer periphery by the applicator or manually. '~ith the other ends 22B released from the applicator and stretched as shown in ~1ig. 7 (1), both the lower segment 8 and the segment 6 are raised by the cylinder device to fit them to the upper segment 7, whereby the end faces 16, 18 serving as the upper nipping portions 20 coact to hold the ends 22B.
In this way, the tire cords are wound on the tread inner surface forming mold segment 6 OI` the core element 4, with their opposite ends 22A, 22B fixedly 113~
held by the u~per and lower nipping ~ortions 20, 21.
The clamping force applied at this time is preferably at least 1 kg ~er cord.
After the tire cords 22 have been held in place on the outer periphery of the core element 4, the element 4 is raised in its entirety by the cylinder device to ~roper -position rela-tive to the stationary upper mold element 2, and -the lower mold element 3 is also raised by an unillustrated cylinder device. At this -tlme, a molding material comprising rubber or an e~uivalently elastic material and in the ~orm of an annular block 14 is placed on the f`eeding means 15 at :the junction between the upper and lower mold elements
2 and 3. The annular block 14 has a volume sufficient to fill the cavity 5.
~ he lower mold element 3 is thus raised toward the upper mold element 2 as shown in l~'ig. 4 for clamping, whereby the annular block 14 is uniformly compressed in its entirety, with -the result that the molding material flows into the cavity and then cured with the -tire cords 22 held in place as seen in Fig. 5. ~or this operation, the leakage of the flowing material from the cavity 5 is prevented by the same means as conventionally used, while bead cores are placed in the bead por~ions.
Alternatively, the core element may be provided wi-th ' means for f`orming grooves for rigid rings as will be described in detail with reference to a second embodiment.
'~he pressure app]ied to the molding material to cause t~e same to flow would act on the tire cords 22 to displace )r disturb the cords 22, but since the cords 22 are fixedly held at the opposite ends 22A, 22B by the upper and lower nipping portions 20, 21 in the illustrated embodiment, sucn displacement or disturbance is avoidable.
The positions of the opposite ends 22A, 22B are determined by the upper and. lower nipping portions 20, 21 which are disposed subs-tantially symmetrically ~iith re-:pect to the equatoriæl line of the tire to be prodv.ced. ~or example, the pairs of nipping portions are located at t~le positions of the tire shoulders as illustrated, or at positions closer to or away from the equatorial line, whereby the tire is given the desirea rigidity and flexibility.
Since the tire cords 22 have a sub~tantia.lly small elongation and are fixedly nipped at their oPposite ends 22A, 22B, the cords can be placed àccurately in position. However, when the stretch of the cords can not be absorbed in the range A shown in I1'ig. 6 dve to the flow of the molding material, depending on the properties of the cords 22 or of the molding material, the en~s 22B
bear on the wall 23A as seen in r`ig. 7 (2), and the 113681~
stretched portions are accommodated in t~e curved recess 23. This ~ermi-ts the cords 22 to position accurately.
When the segment 7 is also provided ~iith the curved recess 25 positioned radia,lly inwardly from the recess 23, the corcl ends 22B may be placed in a curled form in the recess 25 before molding and thereafter enclosed in a portion of the molding material. 'l'he rupture of cord or contact thereof with the tire inner surface can then be prevented.
Figs. 9 to 11 show a second embodiment of the invention which include means for absorbing or accommodat-ing the stretch of tire cords 22 more effectively.
The tread inner surface forming segment 6 shown in ~`igs. 9 and 10 is formed on its outer peripheral surface with indentations 6A and projections 6B in a line pattern e~tending along the equatorial lihe of the tire as seen in Fig. 11 (1), or in a honeycomb pattern as shown in Fig. 11 (23.
According to the second embodiment, the tire cords 22, when subjected to the flow of molding material over the area A indicated, will flex or bend along projections and indentations, whereby the stretch of the cords 22 can be accommodated effectively without being displaced or dist~rbed.
As illustrated in ~ig. 10, the curved recesses 1~36~1~
23, 2~, 25 all-eady described may preferably be ~rovided in combination with the indentati.ons 6A an~ projections 6B, but the indentations and proJections alone may be providèd between the pairs of upper and lower nipping portions 20, 21 as means for accommodating the stretch of cords.
lfurther as best seen in rlig. 10, the mold segments 7, 8 of -the second embodiment are provided, at the portions corresponding to the tire beads, with projections 7A, 8~ for forming bead grooves. i~ith the use of this embodiment, rigid rings R can be fitted in the grooves formed in the tire as seen in ~igs. 13 to 15.
l?ig. 10 also shows that each pair of the nipping portions 20, 21 of the second embodiment has a curved recess 25 for preventing the rupture of cords.
~ ith either of the first and second embodiments, tire cords 22 can be applied in at least two layers.
Although the cords in the plurality of layers may preferably be fixedly held at their opposite ends in this case, the cords of the layers may be held by the lower nipping por-tions 21 each at i-ts one end, and the other ends of the cords in the lowermost layer only may be held by the upper nipping portions 20, with the other cord ends in the other layers left as free ends. In this case, the stretch of the cords at the free ends due to the flo~r 113~
must be taken into consideration, so that the opposite ends of tte cords should be -positioned symmetrically Wit~l respect to the equatoria~ line of the tire.
Thus -the tire cord can be held in place at least at one end. This is also true of the case in which the tire has a single layer of cords. Accordingly the embodiments may have at least one pair of ni~ping portions, i.e. the lower nipping portions 21.
Fi~. 12 schematically shows a third embodiment of the invention, which differs from the foregoing embodiments in that a liquid molding material is used in place of an annular block of rubber or like elastic material. The embodiment has feeding means 15 in the Iorm of a plurality of liquid inlet bores disposed close to the bead forming portions and arranged circumferentially.
The outer mold has a liquid outlet bore 15A.
With the third embodiment, the core mold element with tire cords 22 wound thereon, and the upper and lower mold elements 2, 3 are clamped together to form a cavity 5, into which a liquid molding material is injected. The third embodiment has the same construction as the first embodiment with the exception of this feature, so that throughout several views of the drawings concerned, ]ike parts are referred to by like ref'erence numerals.
The second and third embodiments can be combined :
~13~
into another embo(liment.
In the case of any ol` the foregoing embodiments, the tire molded is released from the mold in the same manner as in the prior art after the curing of the molding materi~l.
~ 'ig. 13 shows a tub~less tire T obtained by the apparatus of this invention and having rigid rings R
fitted in the circumferential grooves in the bead portions.
The opposite ends 22A, 22B of the tire cords 22 are positioned symmetrically with respect to the equatorial line 0-0 of the tire, substantially at its shoulders. The sidewalls of the tire include elastic deformable portions Tl, T2. The tire has durability against ~uncture and assures a comfortable ride.
~'ig. 14 shows a more preferred tire T having annular protrusions T3, T4 fo~med by the recesses 25 and having enclosed therein the opposite ends 22A, 22B of tire cords. ~`ig. 15 shows a tire having projections or indentations T5 on the inner side of the tread and made by an apparatus according to the second embodiment of the invention shown in ~igs. 9 and 10.
The tubeless tires shown in ~'igs. 13 to 15 may further incorporate a tube. Apparently tires so adapted can be produced by the same apparatus and method as described above.
113~
According to t;he present invention described above, tubeless pneumatic tires can be produced ~;;hich com~rise a main body of rubber or equivalently elastic material and tire cords not connected ~ the beads, and ~hich have resistance to puncture and suitable rigidity and assure a comfortable ride, ~ith the tire cords positioned accurately in place free of displacement or disturbance. Thus the tires have various outstanding advantz.ges for use.
,
~ he lower mold element 3 is thus raised toward the upper mold element 2 as shown in l~'ig. 4 for clamping, whereby the annular block 14 is uniformly compressed in its entirety, with -the result that the molding material flows into the cavity and then cured with the -tire cords 22 held in place as seen in Fig. 5. ~or this operation, the leakage of the flowing material from the cavity 5 is prevented by the same means as conventionally used, while bead cores are placed in the bead por~ions.
Alternatively, the core element may be provided wi-th ' means for f`orming grooves for rigid rings as will be described in detail with reference to a second embodiment.
'~he pressure app]ied to the molding material to cause t~e same to flow would act on the tire cords 22 to displace )r disturb the cords 22, but since the cords 22 are fixedly held at the opposite ends 22A, 22B by the upper and lower nipping portions 20, 21 in the illustrated embodiment, sucn displacement or disturbance is avoidable.
The positions of the opposite ends 22A, 22B are determined by the upper and. lower nipping portions 20, 21 which are disposed subs-tantially symmetrically ~iith re-:pect to the equatoriæl line of the tire to be prodv.ced. ~or example, the pairs of nipping portions are located at t~le positions of the tire shoulders as illustrated, or at positions closer to or away from the equatorial line, whereby the tire is given the desirea rigidity and flexibility.
Since the tire cords 22 have a sub~tantia.lly small elongation and are fixedly nipped at their oPposite ends 22A, 22B, the cords can be placed àccurately in position. However, when the stretch of the cords can not be absorbed in the range A shown in I1'ig. 6 dve to the flow of the molding material, depending on the properties of the cords 22 or of the molding material, the en~s 22B
bear on the wall 23A as seen in r`ig. 7 (2), and the 113681~
stretched portions are accommodated in t~e curved recess 23. This ~ermi-ts the cords 22 to position accurately.
When the segment 7 is also provided ~iith the curved recess 25 positioned radia,lly inwardly from the recess 23, the corcl ends 22B may be placed in a curled form in the recess 25 before molding and thereafter enclosed in a portion of the molding material. 'l'he rupture of cord or contact thereof with the tire inner surface can then be prevented.
Figs. 9 to 11 show a second embodiment of the invention which include means for absorbing or accommodat-ing the stretch of tire cords 22 more effectively.
The tread inner surface forming segment 6 shown in ~`igs. 9 and 10 is formed on its outer peripheral surface with indentations 6A and projections 6B in a line pattern e~tending along the equatorial lihe of the tire as seen in Fig. 11 (1), or in a honeycomb pattern as shown in Fig. 11 (23.
According to the second embodiment, the tire cords 22, when subjected to the flow of molding material over the area A indicated, will flex or bend along projections and indentations, whereby the stretch of the cords 22 can be accommodated effectively without being displaced or dist~rbed.
As illustrated in ~ig. 10, the curved recesses 1~36~1~
23, 2~, 25 all-eady described may preferably be ~rovided in combination with the indentati.ons 6A an~ projections 6B, but the indentations and proJections alone may be providèd between the pairs of upper and lower nipping portions 20, 21 as means for accommodating the stretch of cords.
lfurther as best seen in rlig. 10, the mold segments 7, 8 of -the second embodiment are provided, at the portions corresponding to the tire beads, with projections 7A, 8~ for forming bead grooves. i~ith the use of this embodiment, rigid rings R can be fitted in the grooves formed in the tire as seen in ~igs. 13 to 15.
l?ig. 10 also shows that each pair of the nipping portions 20, 21 of the second embodiment has a curved recess 25 for preventing the rupture of cords.
~ ith either of the first and second embodiments, tire cords 22 can be applied in at least two layers.
Although the cords in the plurality of layers may preferably be fixedly held at their opposite ends in this case, the cords of the layers may be held by the lower nipping por-tions 21 each at i-ts one end, and the other ends of the cords in the lowermost layer only may be held by the upper nipping portions 20, with the other cord ends in the other layers left as free ends. In this case, the stretch of the cords at the free ends due to the flo~r 113~
must be taken into consideration, so that the opposite ends of tte cords should be -positioned symmetrically Wit~l respect to the equatoria~ line of the tire.
Thus -the tire cord can be held in place at least at one end. This is also true of the case in which the tire has a single layer of cords. Accordingly the embodiments may have at least one pair of ni~ping portions, i.e. the lower nipping portions 21.
Fi~. 12 schematically shows a third embodiment of the invention, which differs from the foregoing embodiments in that a liquid molding material is used in place of an annular block of rubber or like elastic material. The embodiment has feeding means 15 in the Iorm of a plurality of liquid inlet bores disposed close to the bead forming portions and arranged circumferentially.
The outer mold has a liquid outlet bore 15A.
With the third embodiment, the core mold element with tire cords 22 wound thereon, and the upper and lower mold elements 2, 3 are clamped together to form a cavity 5, into which a liquid molding material is injected. The third embodiment has the same construction as the first embodiment with the exception of this feature, so that throughout several views of the drawings concerned, ]ike parts are referred to by like ref'erence numerals.
The second and third embodiments can be combined :
~13~
into another embo(liment.
In the case of any ol` the foregoing embodiments, the tire molded is released from the mold in the same manner as in the prior art after the curing of the molding materi~l.
~ 'ig. 13 shows a tub~less tire T obtained by the apparatus of this invention and having rigid rings R
fitted in the circumferential grooves in the bead portions.
The opposite ends 22A, 22B of the tire cords 22 are positioned symmetrically with respect to the equatorial line 0-0 of the tire, substantially at its shoulders. The sidewalls of the tire include elastic deformable portions Tl, T2. The tire has durability against ~uncture and assures a comfortable ride.
~'ig. 14 shows a more preferred tire T having annular protrusions T3, T4 fo~med by the recesses 25 and having enclosed therein the opposite ends 22A, 22B of tire cords. ~`ig. 15 shows a tire having projections or indentations T5 on the inner side of the tread and made by an apparatus according to the second embodiment of the invention shown in ~igs. 9 and 10.
The tubeless tires shown in ~'igs. 13 to 15 may further incorporate a tube. Apparently tires so adapted can be produced by the same apparatus and method as described above.
113~
According to t;he present invention described above, tubeless pneumatic tires can be produced ~;;hich com~rise a main body of rubber or equivalently elastic material and tire cords not connected ~ the beads, and ~hich have resistance to puncture and suitable rigidity and assure a comfortable ride, ~ith the tire cords positioned accurately in place free of displacement or disturbance. Thus the tires have various outstanding advantz.ges for use.
,
Claims (7)
1. An apparatus for producing pneumatic tires comprising at least three fittable mold components of an upper mold element, a lower mold element and a core mold element for defining a cavity having the shape of the tires, and means for feeding rubber or an equivalently elastic molding material to the cavity in an amount sufficient to fill the cavity, the core mold element comprising at least three divided fit-table mold segments for forming the inner surfaces of the tire tread and tire sidewalls including a pair of beads, the tread inner surface forming mold segment and at least one of the sidewall inner surface forming mold segments having on their opposed faces nipping portions movable toward or away from each other for holding at least one end of each of tire cords.
2. An apparatus as defined in claim 1 wherein the tire cords can be provided along the tread inner surface forming mold segment of the core mold element, and two pairs of nipping portions are disposed symmetrically with respect to the equatorial line of the tire except where the beads are formed for holding the opposite ends of the tire cords, the nipping portions in each pair being movable toward or away from each other.
3. An apparatus as defined in claim 1 wherein .
the sidewall inner surface forming mold segments of the core mold element have bead forming portions each in the form of an annular projection and extending symmetrically with respect to the equatorial line of the tire therealong.
the sidewall inner surface forming mold segments of the core mold element have bead forming portions each in the form of an annular projection and extending symmetrically with respect to the equatorial line of the tire therealong.
4. An apparatus as defined in claim 1 wherein the tread inner surface forming mold segment of the core mold element is provided on its outer peripheral surface with projections and indentations serving as means for accommodating the displacement and elongation of tire cords due to the flow of the molding material.
5. An apparatus as defined in claim 2 wherein the pairs of nipping portions are disposed at the portions of the core mold element corresponding to the shoulders of the tire and positioned symmetrically of the equatorial line of the tire, and one of the nipping portions in each pair has a curved annular recess for accommodating therein the corresponding end of each of the tire cords.
6. An apparatus as defined in claim 4 wherein means for accommodating the displacement and elongation of tire cords due to the flow of the molding material is formed as a cord end bearing wall on each of the sidewall inner surface forming mold segments opposed to the tread inner surface forming mold segment.
7. An apparatus as defined in claim 5 or 6 wherein one of the nipping portions in each pair is formed, centripetally inwardly from its outer periphery, with an annular projection for winding the corresponding end of each cord therearound and enclosing the end in a molded portion of the molding material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14169679A JPS5664852A (en) | 1979-10-31 | 1979-10-31 | Method and apparatus for making tubeless pneumatic tire |
| JP54-141696 | 1979-10-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1136811A true CA1136811A (en) | 1982-12-07 |
Family
ID=15298076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000362302A Expired CA1136811A (en) | 1979-10-31 | 1980-10-14 | Apparatus for producing pneumatic tires |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4286942A (en) |
| JP (1) | JPS5664852A (en) |
| AU (1) | AU523997B2 (en) |
| CA (1) | CA1136811A (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4378327A (en) * | 1981-02-11 | 1983-03-29 | The Firestone Tire & Rubber Company | Method of molding tires |
| US4378204A (en) * | 1981-02-11 | 1983-03-29 | The Firestone Tire & Rubber Company | Mold for making tires |
| US4341251A (en) * | 1981-02-11 | 1982-07-27 | The Firestone Tire & Rubber Company | Tire and method of making |
| US4655274A (en) * | 1984-10-26 | 1987-04-07 | Ube Industries, Ltd. | Horizontal mold clamping and vertical injection type die cast machine |
| JPS61194234U (en) * | 1985-05-23 | 1986-12-03 | ||
| JPS6270377U (en) * | 1985-10-23 | 1987-05-02 | ||
| JPH0696270B2 (en) * | 1986-07-17 | 1994-11-30 | 株式会社ブリヂストン | Method for manufacturing wide loop-shaped elastic belt having recess on inner peripheral surface |
| JPH0313685U (en) * | 1989-06-26 | 1991-02-12 | ||
| US6403003B1 (en) | 1999-08-10 | 2002-06-11 | Jetta Company Limited | Injection molded doll head |
| JP4275476B2 (en) * | 2003-07-24 | 2009-06-10 | 株式会社ブリヂストン | Tire manufacturing core |
| US7736454B2 (en) * | 2004-02-12 | 2010-06-15 | The Goodyear Tire & Rubber Company | Method for incorporating an annular antenna and electronics into a tire |
| WO2007101298A1 (en) * | 2006-03-09 | 2007-09-13 | Resmed Ltd | Induction heating system and method for humidifier |
| FR2962371B1 (en) * | 2010-07-07 | 2014-03-21 | Michelin Soc Tech | TOP REINFORCEMENT FOR AIR TIRE |
| WO2013097800A1 (en) * | 2011-12-30 | 2013-07-04 | Yuan Bing | Method and device for making silastic cupping appliance |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3123122A (en) * | 1959-12-21 | 1964-03-03 | Pneumatic tire with reinforcement in zenith portion thereof | |
| GB965269A (en) * | 1961-10-05 | 1964-07-29 | Witold Julian Kopytynski | Improvements in or relating to the manufacture of tyres for vehicles |
| FR1489168A (en) * | 1966-06-07 | 1967-07-21 | Method and device for the manufacture of tires by injection | |
| AT316336B (en) * | 1970-08-05 | 1974-07-10 | Semperit Ag | Molded body made of an elastomeric material, and methods and devices for its production |
| GB1506714A (en) * | 1974-05-28 | 1978-04-12 | Dunlop Ltd | Pneumatic tyre manufacture |
| DE2514973C3 (en) * | 1975-04-05 | 1978-06-08 | Sopecom S.A., Freiburg (Schweiz) | Injection molding device for manufacturing vehicle tires |
| IT1078794B (en) * | 1976-09-22 | 1985-05-08 | Pirelli | MALE COMPATIBLE IN SECTORS OF A MOLD FOR THE VULCANIZATION OF TIRES |
-
1979
- 1979-10-31 JP JP14169679A patent/JPS5664852A/en active Granted
-
1980
- 1980-10-14 CA CA000362302A patent/CA1136811A/en not_active Expired
- 1980-10-15 US US06/197,231 patent/US4286942A/en not_active Expired - Lifetime
- 1980-10-27 AU AU63710/80A patent/AU523997B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5664852A (en) | 1981-06-02 |
| AU6371080A (en) | 1982-05-06 |
| JPS5750186B2 (en) | 1982-10-26 |
| AU523997B2 (en) | 1982-08-26 |
| US4286942A (en) | 1981-09-01 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |