Mold for vulcanizing pre-shaped pneumatic tires

Claim 2

In a mold for vulcanizing pre-shaped pneumatic tires wherein a toroidal mold cavity is formed of axially opposed separable sidewall mold sections and a plurality of radially movable tread-forming mold segments arranged about the mold axis and supported by radially outwardly located actuator means, and the tread-forming mold segments cooperate to form an annular tread-forming mold surface facing the mold cavity, and guide means actuate said tread-forming mold segments into radial movement for opening and closing of the mold cavity in response to axial relative movement; the improvement wherein: said guide means and said tread-forming mold segments are provided with facing like-shaped parallel guide surfaces in sliding contact at respective radially outward sides of the tread-forming mold segments, said guide surfaces being parallel to respective guide axes which are inclined with respect to the mold axis, an inclination angle of the guide axes relative to the mold axis being selected to impart radial movement to each of the tread-forming mold segments; each of said guide surfaces being curved about its respective guide axis to maintain extended guide surface contact between the guide means and the tread-forming mold segments throughout the opening and closing of the mold cavity for enhanced structural support of the tread-forming mold segments during said movement.

Claim 3

In a mold for vulcanizing pre-shaped pneumatic tires wherein a toroidal mold cavity is formed of axially opposed separable sidewall mold sections and a plurality of radially movable treadforming mold segments arranged about the mold axis and supported by radially outwardly located actuator means, and the treadforming mold segments cooperate to form an annular tread-forming mold surface facing the mold cavity, and guide means actuate said tread-forming mold segments into radial movement for opening and closing of the mold cavity in response to axial relative movement; the improvement wherein: said guide means and said tread-forming mold segments are provided with facing like-shaped parallel guide surfaces in sliding contact at respective radially outward sides of the tread-forming mold segments, said guide surfaces being parallel to respective guide axes which are inclined with respect to the mold axis, an inclination angle of the guide axes relative to the mold axis being selected to impart radial movement to each of the tread-forming mold segments; each of said guide surfaces being curved about its respective guide axis to maintain extended guide surface contact between the guide means and the tread-forming mold segments throughout the opening and closing of the mold cavity for enhanced structural support of the tread-forming mold segments during said movement.

Claim 4

In a mold for vulcanizing pre-shaped pneumatic tires wherein a toroidal mold cavity is formed of axially opposed separable sidewall mold sections and a plurality of radially movable treadforming mold segments arranged about the mold axis and supported by radially outwardly located actuator means, and the treadforming mold segments cooperate to form an annular tread-forming mold surface facing the mold cavity, and guide means actuate said tread-forming mold segments into radial movement for opening and closing of the mold cavity in response to axial relative movement; the improvement wherein: said guide means and said tread-forming mold segments are provided with facing like-shaped parallel guide surfaces in sliding contact at respective radially outward sides of the tread-forming mold segments, said guide surfaces being parallel to respective guide axes which are inclined with respect to the mold axis, an inclination angle of the guide axes relative to the mold axis being selected to impart radial movement to each of the tread-forming mold segments; each of said guide surfaces being curved about its respective guide axis to maintain extended guide surface contact between the guide means and the tread-forming mold segments throughout the opening and closing of the mold cavity for enhanced structural support of the tread-forming mold segments during said movement.

Claim 5

The mold of claim 1 wherein said guide surfaces are segments of cylindrical surfaces parallel to the respective guide axes.

Claim 6

The mold of claim 1 wherein each guide surface is a circular cylinder inclined relative to the mold axis.

Claim 7

The mold of claim 1 wherein said guide axes are oriented to form an inclination angle with the mold axis that is between about 5* and about 40*.

Claim 8

The mold of claim 4 wherein said guide axes are oriented to form an inclination angle with the mold axis that is between about 15* and about 30*.

Claim 9

The mold of claim 1 wherein there are at least six of said tread-forming mold segments, whereby the radius of curvature of each of the guide surfaces is sufficiently small to provide radially extended guidance contact between the guide means and the tread-forming mold segments for enhanced segment support.

Claim 10

The mold of claim 1 wherein said guide means includes an annular trough-shaped member comprising a ring body and an annular radially outwardly flared support section being provided with a plurality of said guide surfaces which face radially inwardly and are uniformly distributed about the mold axis, and guide elements located between the guide surfaces on the support section slidingly to engage circumferential sides of the tread-forming mold segments.

Claim 11

The mold of claim 7 wherein said guide elements are of generally tapered shape and sized to maintain circumferential engagement with the tread-forming mold segments during radial movement thereof.

Claim 12

The mold of claim 7 wherein said outwardly flared support section is sized to extend between about one to about two times the height of a tread-forming mOld segment as measured along a line parallel to the axis of a guide surface.

Claim 13

In a mold for vulcanizing belted radial-cord tires wherein a circular mold cavity is formed of axially opposed separable sidewall mold segments and a plurality of radially movable tread-forming mold segments arranged about the mold axis and supported by radially outwardly located actuators, the improvement comprising: an annular body formed of a ring segment and a radially outwardly flared annular support section, said annular body and said tread-forming mold segments being mounted for movement of one of them relative to the other along the mold axis for actuation of the mold, said flared support section being provided with a plurality of guide surfaces arranged about the mold axis and facing the mold axis, each of said guide surfaces being cylindrically curved and oriented at an inclination angle with respect to the mold axis to effect opening and closing of the mold during said relative axial movement; and said plurality of tread-forming mold segments are shaped jointly to form an annular tread-forming mold surface facing the mold cavity, each of said tread-forming mold segments being provided with a curved guide surface of like shape as the guide surface on the flared support section of the annular body, said tread-forming segments being mounted to the annular body for sliding movement between the facing curved guide surfaces thereof along the angle of inclination thereof whereby to provide radial movement of the tread-forming mold segments in response to said relative axial movement while maintaining guide surface engagement throughout said motion for enhanced structural support of the segments.

Claim 14

In a mold for vulcanizing belted radial-cord tires wherein a circular mold cavity is formed of axially opposed separable sidewall mold segments and a plurality of radially movable tread-forming mold segments arranged about the mold axis and supported by radially outwardly located actuators, the improvement comprising: an annular body formed of a ring segment and a radially outwardly flared annular support section, said annular body and said tread-forming mold segments being mounted for movement of one of them relative to the other along the mold axis for actuation of the mold, said flared support section being provided with a plurality of guide surfaces arranged about the mold axis and facing the mold axis, each of said guide surfaces being cylindrically curved and oriented at an inclination angle with respect to the mold axis to effect opening and closing of the mold during said relative axial movement; and said plurality of tread-forming mold segments are shaped jointly to form an annular tread-forming mold surface facing the mold cavity, each of said tread-forming mold segments being provided with a curved guide surface of like shape as the guide surface on the flared support section of the annular body, said tread-forming segments being mounted to the annular body for sliding movement between the facing curved guide surfaces thereof along the angle of inclination thereof whereby to provide radial movement of the tread-forming mold segments in response to said relative axial movement while maintaining guide surface engagement throughout said motion for enhanced structural support of the segments.

Claim 15

The mold of claim 10 further including: a plurality of guide elements disposed circumferentially adjacent the guide surfaces, said guide elements being shaped to retain the tread-forming mold segments in sliding surface engagement with the annular body guide surfaces throughout mold opening and closing.

Claim 16

The mold of claim 11 wherein the guide elements are tapered for radial convergence of said segments during the mold-closing motion thereof.

Claim 17

The mold of claim 1 wherein each guide surface has a circular cross-section as determined by a plane perpendicular to respective guide axes.

Claim 18

The mold of claim 3 wherein each guide surface has a circular cross-section as determined by a plane perpendicular to the respective guide axes.

Claim 19

The mold of claim 1 wherein each guide surface has an elliptical cross-section as determined by a plane perpendicular to the mold axis.

Claim 20

The mold of claim 3 wherein each guide surface has an elliptical cross-section as determined by a plane perpendicular to the mold axis.

Claim 21

The mold of claim 15 wherein the elliptical cross-section of each guide surface does not overlap with the elliptical cross section of an adjacent guide surface.

Claim 22

The mold of claim 16 wherein each elliptical cross-section guide surface is a portion of non-overlapping adjacent cylinders.

Claim 23

In a mold for vulcanizing belted radial-cord tires wherein a circular mold cavity is formed of axially opposed separable sidewall mold segments and a plurality of radially movable tread-forming mold segments arranged about the mold axis and supported by radially outwardly located actuators, the improvement comprising: an annular body formed of a ring segment and a radially outwardly flared annular support section, said annular body and said tread-forming mold segments being mounted for movement of one of them relative to the other along the mold axis for actuation of the mold, said flared support section being provided with a plurality of guide surfaces arranged about the mold axis and facing the mold axis, each of said guide surfaces being elliptically curved and oriented at an inclination angle with respect to the mold axis to effect opening and closing of the mold during said relative axial movement; and said plurality of tread-forming mold segments are shaped jointly to form an annular tread-forming mold surface facing the mold cavity, each of said tread-forming mold segments being provided with a curved guide surface of like shape as the guide surface on the flared support section of the annular body, said tread-forming segments being mounted to the annular body for sliding movement between the facing curved guide surfaces thereof along the angle of inclination thereof whereby to provide radial movement of the tread-forming mold segments in response to said relative axial movement while maintaining guide surface engagement throughout said motion for enhanced structural support of the segments.

Claim 24

In a mold for vulcanizing belted radial-cord tires wherein a circular mold cavity is formed of axially opposed separable sidewall mold segments and a plurality of radially movable tread-forming mold segments arranged about the mold axis and supported by radially outwardly located actuators, the improvement comprising: an annular body formed of a ring segment and a radially outwardly flared annular support section, said annular body and said tread-forming mold segments being mounted for movement of one of them relative to the other along the mold axis for actuation of the mold, said flared support section being provided with a plurality of guide surfaces arranged about the mold axis and facing the mold axis, each of said guide surfaces being elliptically curved and oriented at an inclination angle with respect to the mold axis to effect opening and closing of the mold during said relative axial movement; and said plurality of tread-forming mold segments are shaped jointly to form an annular tread-forming mold surface facing the mold cavity, each of said tread-forming mold segments being provided with a curved guide surface of like shape as the guide surface on the flared support section of the annular body, said tread-forming segments being mounted to the annular body for sliding movement between the facing curved guide surfaces thereof along the angle of inclination thereof whereby to provide radial movement of the tread-forming mold segments in response to said relative axial movement while maintaining guide surface engagement throughout said motion for enhanced structural support of the segments.

Claim 25

The mold of claim 19 further including: a plurality of guide elements disposed circumferentially adjacent the guide surfaces, said guide elements being shaped to retain the tread-forming mold segments in sliding surface engagement with the annular body guide surfaces throughout mold opening and closing.