US 5,458,727 AGranted

Direct extrusion cushion-gumming and skive-filling of tire casings for retreading

AssigneeAZ Formen- und Maschinenbau GmbH

InventorPaul Meyer

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Abstract

A tire retreading device has a tread feeding device for feeding the tread to a tire casing and an extruder for extruding a cushion gum layer onto the tire casing. The extruder has a first and a second lip defining the extrusion die. The first lip, positioned behind the second lip in the direction of rotation of the tire casing, projects in a direction toward the tire casing relative to the second lip. The first lip is an applicator shoe that is pressed under prestress against the tire casing so as to deform the tire casing. With the retreading device a cushion gum layer is applied to the tire casing and during the application the applicator shoe is pressed against the tire casing with such a pressing force that a radius of curvature of the tire casing conforms to a radius of curvature of the applicator shoe. With this measure, depressions in the surface of the tire casing are filled with excess cushion gum.

Claims15

Dependent claims

A tire retreading device comprising:

an extruder for extruding a cushion gum layer onto said tire casing, said extruder having a first and a second lip defining an extrusion die, wherein said first lip projects in a direction toward said tire casing past said second lip;
a means for rotating said tire casing past said extrusion die, wherein said protruding first lip is arranged downstream of said second lip in a direction of rotation of said tire casing;
a means for pressing said die into forceful contact with said tire casing, wherein said first lip is an applicator shoe that is pressed against said tire casing so as to deform said tire casing, wherein said applicator shoe has a surface facing said tire casing, wherein said surface has a chamfer that extends at an angle to a surface of said tire casing, said chamfer oriented such that the surface of said applicator shoe is at an increasing distance from the tire surface in a direction toward said second lip and counter to said direction of rotation of said tire casing;
and
a tread feeding device for feeding the tread to said tire casing after extrusion of said cushion gum layer onto said tire casing.

2 more elements

Dependencies are inferred from the claim text.