Automotive air tire

FIELD: transport.

SUBSTANCE: invention relates to furniture for transport facilities. Tire comprises at least two cord plies crossing at the angle to reinforce the ring. Said cords are reinforced solely by steel. Every cord ply features tension of <17500 N per dm of width at preset stretching of 1%, cord ply reinforcement makes the angle of 18-45° with tire circumferential direction. Reinforcing ring reinforcement is made of non-metallic material, preferably, of polyether, nylon or hybrid cord, said reinforcing ring having total tension >2000 N per d of width equal to 1%.

EFFECT: higher operating performances.

10 cl

 

The invention relates to pneumatic tires for vehicles containing two or more cord layers, intersecting at an angle and containing steel reinforcement, and also contain a reinforcing brace, consisting of one or more layers containing reinforcement.

Design of pneumatic tyres for vehicles quite well known to specialists in this field. Radial tires contain Brecker and, often, the reinforcing brace.

Brecker, consisting of two or more intersecting at an angle of cord layers, provides rigidity of the tread of the tire in the longitudinal and transverse directions. It serves to transfer forces when driving, improves lateral direction and reduces tire wear. The reinforcing band, consisting of one or more oriented along the circumference of the layer mainly serves to perception of effort in the circumferential direction, for example to limit bus expansion caused by centrifugal forces during operation of the tire. The reinforcing band may overlap Brecker, or all of the reinforcing band or individual layers of the bandage may be placed between or under the cord layers.

It is now known and widespread use of steel cords as reinforcing cord in the layers of the breaker. Steel cords are arranged at armor the next layer essentially parallel to and at a distance from each other and embedded in the rubber material. Cord layers used in tires for passenger cars, often contain steel cords having the structure of 2×0.30 mm at a density of stacking cords 80 pieces on DM or more. The structure of the cord 2×0.30 mm means that the two strands (fibers) having a diameter of 0.30 mm twisted to form one cord so that the cord has a diameter of approximately 0,60 mm Cords given diameter forming a layer embedded in the rubber. The larger the diameter of the cord, the more rubber you need for sealing cord and the harder each cord layer, and the harder tyre. Established by the rules of the cord layer is created so that it has a higher voltage than 17500 N on DM width at a preset tension, equal to 1%. The lack of cord layers containing the above steel cords, is that they are relatively heavy and expensive for the materials.

Similarly, it is now known and widespread use of reinforcing bands in combination with steel breakers. Reinforcing tires, used tires for passenger cars, often contain one or two layers of rubberized nylon cords with the structure 940×2 packing density of 80 units per inch is Similar to the reinforcing brace is designed so that at a preset tension, equal to 1% in the direction of continue the Noah length of the cord, creates a force not greater than or equal to 1500 N on DM width. Often used nylon as the material has heat shrink, meaning it shrinks when heated. This is an advantage as when the vulcanization of the tire, and when operating at high speeds, since the reinforcing brace helps to keep the whole Assembly of the breaker. In addition, this prevents the compression reinforcing brace during operation, which is unfavorable for its fatigue strength and can lead to tearing of the material of the bandage.

Efforts in the development of tyres constantly aimed at creating a tire with low cost and low weight, and high performance.

Thus, the aim of the invention is the provision of an inexpensive pneumatic tyres for vehicles with low weight and good performance.

This goal is achieved through the use of cord layers, each of which has a voltage of <17500 N on DM width at a preset tension, equal to 1% in the direction of the longitudinal length of the reinforcement, and the reinforcement (i.e. reinforcing elements) cord layers form an angle of 18° to 45° with the circumferential direction of the tire, with reinforcement (i.e. reinforcing elements) reinforcing brace is made of Nemeth is symbolic and material are etched, and amplifying the band as a whole has a voltage >2000 N on DM width at a preset tension, equal to 1%.

The effect of this invention is that the cord layers of reinforcement is used (i.e. reinforcing elements) with reduced weight, reduced module which is compensated by the relatively large increase in the tensile stress reinforcing brace. Reducing the cost and weight can be achieved, for example, by reducing the number of reinforcing elements on the decimeter or by reducing the diameter of the used reinforcement. Reinforcing elements cord layers may consist of twisted cords in fibers, with each fiber has, for example, a diameter of less than 0.24 mm, and the density of packing of less than or equal to 80 per DM, or consists of individual conductors with a diameter of less than 0.30 mm

To achieve high performance, as in the operation of the bus is obtained a sufficient dynamic area of contact with the ground. The use of cord layers of reinforcing elements with a reduced diameter has the advantageous effect of reducing the weight of pneumatic tires for vehicles. The tire according to the invention has a low cost, improved rolling resistance thanks to its reduced weight and, in addition, she has improved suitability for use is at high speeds.

It is preferable if the reinforcing elements of the cord layers are cords with a range of high tensile strength (HT) or ultra-high strength heat-treated (UHT). Reinforcing elements of high-strength range have, depending on the fiber diameter, a tensile strength of about 3000 MPa to 3500 MPa, while the corresponding reinforcing elements ultra-high-strength range have a strength of about 500 MPa above.

Preferably the reinforcement reinforcing brace is made of materials from the class of polyester or nylon. Similarly, you can apply a hybrid structure of viscose, Lyocell, polyvinyl acetate (PVA), polyethylene naphthalate (PEN), polyolefines (POK), Vectran or aramid with polyester or nylon. It is important that at least one of the materials of the reinforcement had a shrink properties.

It is important that the structure of the reinforcing cord layers and the brace is designed to fit to each other according to the invention, in order to obtain a sufficient dynamic area of contact with the ground during operation of the tire. The reinforcing band is wound, and is wound pattern with gaps, which reduce the effective density of the cords.

Since the tire according to the invention has a reduced weight, this invention sentence is but for use in relatively heavy preserving working property when the damage to the tires, as a self-supporting tyres (SSR tires, or tire containing self-adhesive viscous sealing layer located radially inside the inner layer of the tire.

"Overweight" these tires can advantageously be compensated by the described construction of the cord layers and bandage. Self-supporting tires (SSR-bus = Self - Supporting - Runflat) tires are reinforced profiles in the lateral sides of the tire, where the tire can remain self-supporting and to go some distance even in the deflated condition. Tires with a sealing layer located between the shoulders of the tire on the inner layer of the tire under the tread rubber, characterized in that when the penetration of a foreign body through the tread pneumatic tires for vehicles, it is surrounded by the sealing layer and the possible leakage of air is prevented by the seal, which is formed almost instantly.

A preferred example of the structure of the tyre, passenger car with size 225/45 R 17 according to the invention contains 2-ply belt made of high-strength steel cord with a structure of 2×0,175 and the density of packing approximately 80 pieces on the DM, data of high-strength steel cords form an angle of 28° with the circumferential direction of the tire, and contains a 1-layer band with a cord of polyester with the structure of 1440×2 for laying about 105 pieces on the DM, data cords of polyester is located is approximately in the circumferential direction of the tire cord and block layers. At a preset tension, equal to 1% in the direction of the longitudinal length of the reinforcement, each cord layer has a voltage approximately equal 8700 N on DM width of the reinforcing brace has a voltage approximately equal to 2000 N on DM width at a preset tension, equal to 1%. During operation of the tire is obtained a sufficient dynamic area of contact with the ground.

Pneumatic tire for vehicles according to the invention can be used in a passenger car, van or light truck.

Pneumatic tire for vehicles, according to the invention, in the most General form contains two or more intersecting at an angle and containing a reinforcing cord layer, and a reinforcing band, consisting of one or more layers containing a reinforcement, and the reinforcement cord layers and a reinforcing band positioned essentially parallel to and at a distance from each other and embedded in a rubber material, and each cord layer has a voltage of <17500 N on DM width preset tensile equal to 1% in the direction of the longitudinal length of the reinforcement, the reinforcement cord layers forms an angle from 18° to 45° with the circumferential direction of the tire, the reinforcement reinforcing brace is located inside armir the subsequent layer is approximately in the circumferential direction of the tire and made of a material with shrinking, and amplifying the band as a whole has a voltage >2000 N on DM width at a preset tension, equal to 1%. Signs of paragraphs 1-9 of the claims can be advantageous improvements of the object under item 10.

1. Pneumatic tire for vehicles containing two or more intersecting at an angle and containing a reinforcing cord layer and the reinforcing band, consisting of one or more layers containing a reinforcement, and the reinforcement cord layers is made entirely of steel, are located within each cord layer essentially parallel to and at a distance from each other and embedded in the rubber material,
characterized in that each cord layer has a voltage of <17500 N on DM width at a preset tension, equal to 1% in the direction of the longitudinal length of the reinforcement,
moreover, the reinforcement cord layers form an angle of 18° to 45° with the circumferential direction of the tire,
and moreover reinforcement reinforcing brace is made of non-metallic material, located within the reinforcing layer essentially parallel to and at a distance from each other approximately in the circumferential direction of the tire and are shrinking,
and amplifying the band as a whole has a voltage >2000 N on DM width with the pre-given the m tension, equal to 1%.

2. Pneumatic tire for vehicles according to claim 1, characterized in that the reinforcing cord layer consists of steel cords in high-tensile (HT) or ultra-high strength heat-treated (UHT) range strength.

3. Pneumatic tire for vehicles according to claim 1, characterized in that the reinforcement reinforcing brace is a material selected from the class of polyester or nylon or hybrid structures viscose, Lyocell, polyvinyl acetate (PVA), polyethylene naphthalate (PEN), polyolefines (ROCK), Vectran or aramid with polyester or nylon.

4. Pneumatic tire for vehicles according to claim 2, characterized in that the cords of cord layer have a structure 2×0,175 and located in each cord layer with a density of approximately 110 pieces per inch

5. Pneumatic tire for vehicles according to claim 1, characterized in that the reinforcement reinforcing brace is polyester cord with a structure of 1440×2 packing density of the cords 105 per inch

6. Pneumatic tire for vehicles according to claim 1, characterized in that each reinforcement cord layer forms an equal angle of 27° to 35°, preferably equal to about 28°with the circumferential direction of the tire.

7. Pneumatic tire for vehicles according to claim 1, characterized in that the cord layers are cut cord and layers.

8. Pneumatic tire for vehicles according to claim 1, characterized in that the pneumatic tire for vehicles has properties preservation of the working properties if the damage is due to the use of reinforcing profiles with a broad cross-section located under the broker in the shoulder of the tire and inside side walls of the tire, and closed in a ring around the periphery of the side wall.

9. Pneumatic tire for vehicles according to claim 1, characterized in that the pneumatic tire for vehicles contains self-adhesive viscous sealing layer located radially inside the inner layer of the tire.

10. Pneumatic tire for vehicles containing two or more intersecting at an angle and containing a reinforcing cord layer, and a reinforcing band, consisting of one or more layers containing a reinforcement, and the reinforcement cord layers and a reinforcing band positioned essentially parallel to and at a distance from each other and embedded in the rubber material, each cord layer has a voltage of <17500 N on DM width at a preset tension, equal to 1% in the direction of the longitudinal length of the reinforcement,
moreover, the reinforcement cord layers form an angle of 18° to 45° with the circumferential direction of the tire,
and with armor is of the reinforcing band located within the reinforcing layer is approximately in the circumferential direction of the tire and made of a material with shrinking,
and amplifying the band as a whole has a voltage >2000 N on DM width at a preset tension, equal to 1%.



 

Same patents:

FIELD: transport.

SUBSTANCE: invention relates to vehicle pneumatic tire. Vehicle pneumatic tire has cushion and reinforcing element layer embedded into at least one rubber mixture. The cushion is made of material selected in group consisting of steel, aramid, carbon fibre, natural fibre, magnesium and magnesium compounds. The reinforcing element layer is single or multilayer layer at an angle 0° to 5° to circumferential direction and is made of at least one polyester thread and/or polyester cord.

EFFECT: perfected design.

12 cl, 1 tbl

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Reinforcing elements of circumferential reinforcing elements are composed of twisted cords with maximum tangential modulus of elasticity in out-of-tire state is smaller the maximum tangential modulus of elasticity I initial state by over 15 GPa, preferably, by 20 GPa.

EFFECT: higher fatigue strength.

14 cl, 2 dwg

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Ratio between crown area depth at shoulder end and crown area depth in circumferential median plane is larger than 1.20. Ratio between spacing between maximum wear surface and reinforcing elements in said plane and spacing between maximum wear of reinforcing elements at the ends of said layer of said elements varies from 0.95 to 1.05.

EFFECT: higher fatigue strength.

14 cl, 3 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Tire comprises tight rubber shell 2 and reinforcing structure composed of multiple fibres 30, 40 embedded in layer in rubber. Said reinforcement structure comprises, at least, carcass layer 3 and breaker layer 4. Fibres 30, 40 of said layers 3, 4 are jointed together and directed relative to tire middle plane (P) at angles varying from 90° to 0°. Every said fibre 30, 40 features flat cross-section.

EFFECT: simplified production.

20 cl, 7 dwg

Pneumatic tire // 2456168

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Tire carcass ply is laid between two double beads. Breaker ply is recessed on carcass ply outer peripheral side in tread section. Tread is provided with multiple main grooves extending along tire circle. Maximum depth of each main groove varies from 8.5 mm to 15.0 mm. Relationship between height of actual tire profile SH and that of profile SHstd calculated from tire size is set to 0.97≤α≤0.99. Relationship between contact areas makes 65-70% under conditions of measurements whereat air pressure makes 200 kPa and load making 50% of bearing capacity at said air pressure. Mean contact pressure P varies from 300 kPa to 400 kPa.

EFFECT: longer life, efficient braking on moistened surface.

13 cl, 4 dwg, 1 tbl

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Proposed tire features ellipticity factor equal to or under 50%. Breaker layers 9, apart from outer breaker layer 10, are arranged so that breaker layer cords are arranged at θ 10-70° relative to tire lengthwise direction. Said outer breaker layer 10 is made of coiled layer 12 of coiled tape provided with steel cords in tire lengthwise direction. Said breaker layer 10 comprises section 10A located between fold position Po on opposite sides from tire equator and fold position 10B bent in U-like manner from position Po toward tire equator. Section 10A features width varying from 70% to 80% of width of contact between tread and ground while fold section 10 B has width varying from 5.0 mm to 0.5 of width.

EFFECT: longer life.

9 cl, 8 dwg

Pneumatic tire // 2405682

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly to heavy-duty radial pneumatic tires of relatively small size ratios. Tire comprises toroidal carcass arranged atop two tire beads, undertread band arranged on outer side along carcass radial direction, and tread arranged on outer along radial direction of undertread belt. Undertread belt comprises at least one circular layer arranged on outer side along radial direction of carcass rim part and made up of multiple rubberised cords running along the tire equatorial axis, and at least two inclined layers of undertread belt arranged on circular layer of undertread belt, each being formed by multiple rubberised cords running inclined to tire equatorial axis O. Width of undertread belt circular layers makes at least 60% of the tire total width. Width of at least one inclined layer of undertread belt exceeds that of circular layer. Note that elasticity modulus of the first cords arranged on outer side of undertread belt circular layer is smaller than that of second cords arranged on inner side, across direction of the first cords.

EFFECT: longer life.

10 cl, 3 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Air tire has breaker structure that comprises first breaker layer (51), second breaker layer (52) arranged in radial-inner position relative to first breaker layer (51), third breaker layer (53) arranged in radial inner position relative to first (51) and second (52) breaker layers. Every breaker layer (51, 52, 53) comprises multiple elongated reinforcing elements arranged above 1st, 2nd and 3rd breaker angles. Note here that 1st and 2nd angles vary from 15 to 40 degrees. Second angle has opposite sign relative to 1st breaker angle. Third breaker angle features magnitude varying from 40 to 90 degrees and opposite sign with respect to second angle. Breaker structure comprises also breaker layer (54) arranged at zero degree angle relative to 1st breaker layer (51) comprising elongated reinforcing elements arranged to make, in fact, zero breaker angle,.

EFFECT: perfected performances.

21 cl, 11 dwg

FIELD: transport.

SUBSTANCE: proposed pneumatic tire incorporates a carcass and a tread formed by, at least, two tread layers made up of rigid reinforcing elements with alternating crossed-over layers forming, with the peripheral direction, the angles varying from 10° to 45° on the tread crown zone. The said tread crown zone is jointed to two beads by side walls. The tread side thickness-to-tread center thickness ratio makes below 1.20 and the tread crown zone-to-tire total width ratio exceeds or equals 0.89.

EFFECT: higher strength and reliability.

25 cl, 5 dwg

FIELD: transportation.

SUBSTANCE: invention is attributed to pneumatic tire for which factor of H/S type has value exceeding 0.55 and which has radial reinforcement of frame and contains flange reinforcement formed by at least two flange working layers created of inextensible reinforcing elements intercrossing from one layer to another forming with circumferential direction the angles in the range of 10 to 45°. Tyre tread connected with two beads by means of two sidewalls is located over this radial frame reinforcement in radial direction. Crest reinforcement contains at least one layer of circumferential reinforcing elements. Value of ratio of crest block width at the end of shoulder area to crest block width at center circumferential plane is less than 1.20, and value of ratio of axial width of at least one layer of circumferential reinforcing elements to axial width of tire tread exceeds 0.5 and preferably exceeds 0.6.

EFFECT: tire strength and reliability is improving.

23 cl, 5 dwg

FIELD: transport.

SUBSTANCE: invention relates to car tires suitable for sportsters. Tire comprises tread divided by tire mid surface into first semi-tread (41) extending axially from mid surface to tread first edge (45). Note here that first semi-tread includes the primary circumferential groove (141) opening to rolling surfaces. Besides, tire includes semi-tread (42) extending axially from mid surface to tread second edge (46). Additionally, tire includes extra stiffener (151) composed of multiple radially-oriented thread-like reinforcing elements. Note here that said extra stiffener is located in radial direction from carcass reinforcing element inner side and levelled directly in radial direction relative to the primary circumferential groove.

EFFECT: more uniform wear, longer life, higher stiffness of tire crown zone.

9 cl, 18 dwg

FIELD: transport.

SUBSTANCE: proposed tire comprises carcass including at least one carcass ply (101), breaker (105) arranged radially outward relative to said carcass. Said breaker comprises the following components: First breaker ply (105a) and second breaker ply (105b). Every of said plies comprises reinforcing cords crossing at the angle to 10-40 degrees. Third breaker ply (105c) includes cords arranged at 10-70 degrees and tread strip (106). It includes at least two inserts (104) arranged between appropriate axial edges of said breaker (105) and said tread strip (106). Every said insert includes first part (104a) converging in equatorial plane of the tire. Every said insert is made of first vulcanised elastomer including diene polymer and definite amount of reinforcing filler. Said reinforcing filler contains at least 70% of silicon dioxide.

EFFECT: higher rolling resistance.

15 cl, 2 dwg, 5 tbl

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Reinforcing elements of circumferential reinforcing elements are composed of twisted cords with maximum tangential modulus of elasticity in out-of-tire state is smaller the maximum tangential modulus of elasticity I initial state by over 15 GPa, preferably, by 20 GPa.

EFFECT: higher fatigue strength.

14 cl, 2 dwg

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Ratio between crown area depth at shoulder end and crown area depth in circumferential median plane is larger than 1.20. Ratio between spacing between maximum wear surface and reinforcing elements in said plane and spacing between maximum wear of reinforcing elements at the ends of said layer of said elements varies from 0.95 to 1.05.

EFFECT: higher fatigue strength.

14 cl, 3 dwg

Pneumatic tire case // 2495761

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to car and light truck tires. Tire case comprises tread, belt play consists of metal cord and textile plies, carcass, side strip and bead ring. Metal cord diameter makes 0.55-0.95 mm. Metal cord proper is composed of equal-diameter metal threads. Note here that metal threaded diameter-to-metal cord diameter makes 0.344-0.543, rubberised metal cord pitch makes 1.052-2.083, while metal cord linear density varies from 1.05 to 2.67 g/m. Note also that thickness of every rubberised metal cord ply of breaker makes 0.72-1.52 mm, while metal cord breaking strength is not lower than 400-900±5 N.

EFFECT: lower metal and labor input, electric power savings.

2 dwg

Pneumatic tire case // 2495760

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to car and light truck tires. Tire case comprises tread, belt play consists of metal cord and textile plies, carcass, side strip and bead ring. Metal cord diameter makes 0.57-0.63 mm. Metal cord proper is composed of equal-diameter metal threads. Note here that metal threaded diameter-to-metal cord diameter makes 0.460-0.543, metal cord linear density varies from 1.06 to 1.18 g/m. Note also that thickness of every rubberised metal cord ply of breaker makes 0.75-1.45 mm, while metal cord breaking strength is not lower than 400±5 N.

EFFECT: lower metal and labor input, electric power savings.

2 dwg

Air tire cover // 2467884

FIELD: transport.

SUBSTANCE: invention relates to automotive tires, particularly, to truck radial tires. Proposed cover comprises tread, breaker composed of metal cord and textile layers, carcass, side strips, and bead rings. Metal cord diameter is 0.81-0.90 mm. Metal cord made up of metal threads of equal diameter of 0.31-0.33 mm. Relationship between metal cord spacing in rubberised breaker layer and metal cord diameter makes 1.55-2.22 while linear density of metal cord equals 2.35-2.70 g/m. Note here that relationship between every metal cord rubberized layer in breaker and metal cord diameter makes 1.39-1.74. Note also that thickness of every metal cord rubberised layer in breaker is 1.2-1.5 mm while metal cord tensile strength is not lower than 885±5N.

EFFECT: higher tensile strength and linear density.

2 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Proposed tire features ellipticity factor equal to or under 50%. Breaker layers 9, apart from outer breaker layer 10, are arranged so that breaker layer cords are arranged at θ 10-70° relative to tire lengthwise direction. Said outer breaker layer 10 is made of coiled layer 12 of coiled tape provided with steel cords in tire lengthwise direction. Said breaker layer 10 comprises section 10A located between fold position Po on opposite sides from tire equator and fold position 10B bent in U-like manner from position Po toward tire equator. Section 10A features width varying from 70% to 80% of width of contact between tread and ground while fold section 10 B has width varying from 5.0 mm to 0.5 of width.

EFFECT: longer life.

9 cl, 8 dwg

Tire case // 2422291

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to design of truck radial tires. A case contains tread, breaker consisting of metal-cord and textile layers, casing, sidewalls and bead rings. Metal cord diameter is 0.77-0.85 mm. The metal cord itself is made of metal fibers with equal diameter, and the ratio of metal fiber to metal cord diameter is 0.330-0.410. The ratio of metal cord in rubber-covered breaker layer to metal cord is 2.057-2.743, and linear density of metal cord lays within the range of 2.12-2.34 g/m. Herewith, the thickness of each rubber-covered metal cord layer in breaker is 1.25-1.45 mm, and tensile strength of metal cord is not lower than 875±5 N.

EFFECT: material, labor and energy consumption of tire manufacturing is lowered.

2 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Air tire has breaker structure that comprises first breaker layer (51), second breaker layer (52) arranged in radial-inner position relative to first breaker layer (51), third breaker layer (53) arranged in radial inner position relative to first (51) and second (52) breaker layers. Every breaker layer (51, 52, 53) comprises multiple elongated reinforcing elements arranged above 1st, 2nd and 3rd breaker angles. Note here that 1st and 2nd angles vary from 15 to 40 degrees. Second angle has opposite sign relative to 1st breaker angle. Third breaker angle features magnitude varying from 40 to 90 degrees and opposite sign with respect to second angle. Breaker structure comprises also breaker layer (54) arranged at zero degree angle relative to 1st breaker layer (51) comprising elongated reinforcing elements arranged to make, in fact, zero breaker angle,.

EFFECT: perfected performances.

21 cl, 11 dwg

Up!