Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1996-12-27
2002-04-09
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S128100, C156S130000, C156S130300
Reexamination Certificate
active
06368439
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to a method for making retreaded tires and particularly to a method for making retreaded tires that eliminates the need for spray cement normally applied to the tire casing.
BACKGROUND OF THE INVENTION
Retreaded tires have been available for many years and provide an economical way to gain additional use out of a tire casing after the original tread has become worn. According to one conventional method of retreading, sometimes referred to as cold process retreading, the remaining tread on the used tire is removed by a special buffing machine that grinds away the old tread and leaves a buffed surface to which a new layer of tread may be bonded.
Removal of the old tread from the tire casing provides a generally smooth treadless surface about the circumference of the tire casing. The tire casing may then be examined for injuries, often called skives, which are filled with a repair gum. After completion of the skiving process, the buffed surface is sprayed with a tire cement that provides a tacky surface for application of bonding material and new tread. Then a layer of cushion gum is applied to the back, i.e., the inside surface, of a new layer of tread. The cushion gum and tread are applied in combination about the circumference of the tire casing to create a retreaded tire assembly ready for curing. The cushion gum forms the bonds between the tread and the tire casing during curing.
Following assembly of the tire casing, cement, cushion gum and tread, the overall retreaded tire assembly is placed within a flexible rubber envelope. An airtight seal is created between the envelope and the bead of the tire. The entire enveloped tire assembly is placed within a curing chamber, and subjected to pressure and a raised temperature for a specific period of time. The combination of pressure, temperature and time chemically bonds the layer of cushion gum to both the tire casing and the new tire tread.
The above-described method of cold process retreading works well and provides high quality, retreaded tires. However, in certain applications it would be advantageous to eliminate the spray cement. This is particularly true in geographical areas where there is increased regulation of the use of chemicals within spray cement. Generally, available spray cements include either heptane solvent or methyl chloroform. The heptane solvent has been found to contribute to smog formation, and methyl chloroform, although it does not cause smog, has tended to be substantially more expensive then heptane solvent.
Use of spray cement can also add to the cost of producing retreaded tires due to the product cost and equipment cost. For example, because cementing of the tire casing should only be dome in a well ventilated spray booth, retreading shops must purchase appropriate ventilation equipment. Elimination of the spray cement thus eliminates the need to purchase ventilated spray booths.
A potential solution to smog problems associated with using heptane solvent is the installation of solvent capture equipment at each retreading shop. However, this solution is disadvantageous due to the cost of the equipment and the operational and maintenance costs. The present invention addresses the drawbacks associated with using spray cement during retreading of tires.
SUMMARY OF THE INVENTION
The present invention includes a method for retreading a tire that comprises the steps of removing the tire tread from a tire casing to present a buffed surface. Then, a layer of cushion gum is applied directly to the buffed surface without spraying cement over the buffed surface. A tread layer is wrapped about the layer of cushion gum, and finally, the tire is treated to form bonds between the casing and the layer of cushion gum and between the tread layer and the layer of cushion gum.
Another unique aspect of the invention is a retreaded tire assembly prepared for insertion into a pressurized heating chamber. The tire assembly includes a tire casing having a pair of side walls and a radially outer wall spanning the pair of side walls. The radially outer wall has a buffed surface disposed about the outer circumference of the tire casing. A layer of cushion gum is disposed directly against the buffed surface, and a tread layer is disposed against the cushion gum about the outside circumference of the cushion gum. After appropriate heat and pressure treatment, the tire casing, cushion gum and tread layer became bonded into an integral retreaded tire that may be used on an appropriate over-the-road vehicle.
REFERENCES:
patent: 2675855 (1954-04-01), Heintz
patent: 3698975 (1972-10-01), Hogan, Jr.
patent: 3728181 (1973-04-01), Simmons, Jr.
patent: 3753821 (1973-08-01), Ragen
patent: 3951719 (1976-04-01), Hough
patent: 3964949 (1976-06-01), Kent et al.
patent: 3989563 (1976-11-01), Schelkmann
patent: 4096008 (1978-06-01), Taylor
patent: 4371411 (1983-02-01), Honda et al.
patent: 4600467 (1986-07-01), Perdue
patent: 5277727 (1994-01-01), Seiler et al.
patent: 5306130 (1994-04-01), King et al.
patent: 5342462 (1994-08-01), King et al.
patent: 5342473 (1994-08-01), Bibona et al.
patent: 5354406 (1994-10-01), King et al.
patent: 5503904 (1996-04-01), Majumdar et al.
patent: 2120473 (1994-10-01), None
patent: 0 104 812 (1984-04-01), None
patent: 0 253 793 (1988-01-01), None
patent: 0 528 683 (1993-02-01), None
patent: 730 950 (1996-09-01), None
patent: 96/27493 (1996-09-01), None
Bender David L.
Bundschuh, Jr. James E.
Carlson Lawrence
Logsden Johnathon Leslie
Myers Floyd S.
Bandag Licensing Corporation
Knable Geoffrey L.
Leydig , Voit & Mayer, Ltd.
LandOfFree
Retreaded tires and method for making the same without spray... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Retreaded tires and method for making the same without spray..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Retreaded tires and method for making the same without spray... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2869533