Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-03-17
2001-02-06
Maki, Steven D. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C152S152100, C152S209500, C152S209180, C152SDIG002, C152SDIG003, C156S128600
Reexamination Certificate
active
06183581
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an antistatic tire.
More specifically, the present invention relates to an antistatic tire of the type comprising electric current conductors on the tread, for grounding the static electricity of a vehicle.
2. Background Information
From EP-A-705722, antistatic tires are known to be formed wherein the tread, shoulders and sidewalls are covered with a thin conductive layer of a conducting mix, which is applied uniformly on the tread blocks and in the grooves between the blocks to form an electrical bridge between the sidewalls, shoulders and tread.
The above solution involves several drawbacks, due to rapid in-service wear of the conductive layer portion covering the blocks, and crumbling of the conductive layer portion covering the grooves, as a result of the fatigue stress to which the tread is subjected in use. Crumbling of the conductive layer is especially marked in the groove region, where the effects of fatigue stress concentrate.
As a result, the original continuous conducting layer of the tire is soon interrupted at various points and no longer capable of grounding the electric charges.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a straightforward, low-cost method of producing antistatic tires capable of maintaining lifelong electrical conductivity.
According to the present invention, there is provided a method of producing an antistatic tire, the tire comprising a tread made of at least one electrically insulating mix and defined externally by a rolling surface of the tire; and the method being characterized by comprising the steps of forming a hollow region in the tread, through the rolling surface; pouring into said hollow region a cement comprising a carbon black mix in a volatile liquid; and evaporating the volatile liquid to leave said carbon black mix inside the hollow region and so define, inside the tread, at least one electrically conducting body communicating with said rolling surface.
According to the invention, there is provided a method of producing an antistatic tire comprising the steps of providing a tread having an electrically insulating central portion and a pair of outer electrically conducting shoulders; forming a plurality of spaced slits extending only partially into the tread inwardly from a rolling surface of the tread, the slits extending transversely across the central portion of the tread and into the shoulders; pouring a cement comprising a carbon black mix in a volatile liquid into the slits; evaporating the volatile liquid to leave said carbon black mix inside the slits to define, inside the tread, a continuous electrically conducting body; and connecting two electrically conducting sidewalls to the shoulders to form an antistatic tire having a continuous electrical path extending from the rolling surface of the tread to the sidewalls.
According to a first preferred embodiment of the above method, said tread comprises a number of surface grooves defining a given groove pattern on the tread; and said hollow region being obtained by forming in the tread, through the rolling surface and inside said grooves, a matrix of slits for receiving said cement and so defining, inside the tread, an electrically conducting matrix constituting said electrically conducting body.
According to a further preferred embodiment of the above method, said hollow region is obtained by cutting the tread longitudinally into at least two portions; placing said portions adjacent to each other to define at least one longitudinal gap defining the hollow region; feeding said cement into said gap; and bringing said portions together again.
According to yet a further preferred embodiment of the above method, said hollow region is obtained by forming through holes in the tread.
The present invention also relates to an antistatic tire formed using the above method.
According to the present invention, there is provided an antistatic tire comprising a tread made of one or more electrically insulating mixes and defined externally by a rolling surface; characterized in that said tread has a hollow region formed through the rolling surface, and comprises at least one electrically conducting body housed inside said hollow region and communicating with said rolling surface; said electrically conducting body being formed by pouring into said hollow region a cement comprising a carbon black mix in a volatile liquid; and evaporating said volatile liquid to leave said carbon black mix inside the hollow region.
According to a first preferred embodiment of the above tire, said tread comprises a number of surface grooves defining a given groove pattern on the tread; said hollow region comprising a matrix of slits formed in the tread through the rolling surface and inside said grooves wherein the slits extend only partially into the tread from the rolling surface; and said electrically conducting body comprising an electrically conducting matrix defined by said carbon black mix occupying each said slit.
According to a further preferred embodiment of the above tire, the tread comprises at least two longitudinal portions integral with each other and separated by a gap defining said hollow region; said electrically conducting body being housed inside said gap.
According to a further preferred embodiment of the above tire, the tread comprises a number of through holes; a said electrically conducting body being housed inside each said hole.
REFERENCES:
patent: 2207099 (1940-07-01), Maynard
patent: 2737237 (1956-03-01), Herzegh
patent: 2907365 (1959-10-01), MacDonald
patent: 3039520 (1962-06-01), Meserve
patent: 5872178 (1999-02-01), Kansupada et al.
patent: 5898047 (1999-04-01), Howald et al.
patent: 0 658 452 A1 (1994-12-01), None
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patent: 0 718 127 A1 (1996-06-01), None
patent: 747243 (1996-12-01), None
patent: 0 787 604 A2 (1997-08-01), None
patent: 881060 (1998-12-01), None
patent: 544757 (1941-02-01), None
Ducci Stefano
Kondo Yochiro
Silicani José
Straffi Paolo
Bridgestone Corporationn
Hornickel, Esq. John H.
Maki Steven D.
Sand, Esq. Michael
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