Plastic and nonmetallic article shaping or treating: processes – Repairing or restoring consumer used articles for reuse – By polymerizing – cross-linking – or curing
Reexamination Certificate
2000-03-20
2001-11-27
Ball, Michael W. (Department: 1733)
Plastic and nonmetallic article shaping or treating: processes
Repairing or restoring consumer used articles for reuse
By polymerizing, cross-linking, or curing
C156S094000, C156S150000, C029S888041, C029S402180, C427S142000
Reexamination Certificate
active
06322730
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates in general to a method of repairing metal surfaces which have been damaged by scoring, dentin, grooving or the like and, more specifically to a repair method which comprises filling damaged areas with a metal-filled resin and plating a wear resistant layer thereover.
Metal surfaces of machine parts and the like are often damaged by wear, accident, and the like. Metal surfaces which bear against other metal surfaces during machine operation are subject to scoring and wear grooves that penetrate the surface in localized areas. Other metal surfaces may be accidentally struck, forming dents. Typical surfaces which developed these localized blemishes include the mating surfaces of pistons and inner cylinder walls in hydraulic cylinders,and other devices in which an inner member slides within a tube.
Conventionally, damaged surfaces are ground until the blemishes are removed, the entire surface is replated oversize and the surface is ground to size and polished. This is expensive, time consuming and requires excessive amount of metal to be ground away over the entire surface, even though the blemishes are localized.
Attempts have been made to fill damaged surfaces with an epoxy resin containing metal particles, as described, for example, by Griffen et al. in U.S. Pat. No. 2,984,895. These methods generally require grinding away the damaged surface to provide depth to the repair area and to promote adhesion between the metal and the filled resin. These methods tend to suffer from short repair life, due to a relatively soft wear surface that wears rapidly and failures of adhesion of the repair to the base metal during use.
Others have tried grinding away and knurling the area to be repaired, spraying a coating of metal onto the repair surface and machining the surface to the original configuration. While these repairs may be acceptable for short periods, the characteristics of the sprayed coating are such that wear tends to be rapid. Typical of such methods is that described by Timuska in U.S. Pat. No. 3,004,336.
In particular, hydraulic cylinders are often subject to scoring, grooving, etc. of the mating piston and cylinder surfaces. This localized damage leads to leaking of hydraulic fluid past the cylinder and inefficient operation. A quick, convenient and effective repair for such damage is particularly needed in the hydraulic cylinder field.
Thus, there is a continuing need for improved methods of repairing damaged or worn metal surfaces, such as hydraulic pistons and cylinders which can be rapidly and economically accomplished, provides improved adhesion of the repair material to the damaged surface and provides a tough, long-wearing repaired surface.
SUMMARY OF THE INVENTION
The above noted problems, and others, are overcome in accordance with this invention by a method for repairing damaged or worn metal surfaces which basically comprises the steps of cleaning the area to be repaired, mixing a suitable catalytically hardened resin with a metal powder to form a mixture which, when hardened, will have a coefficient of thermal expansion substantially the same as that of the metal surface, mixing therewith a suitable hardener, filling the damaged area with the mixture and curing the resin. When cure is complete, the surface is dressed to conform to the shape of adjacent undamaged areas and the metal surface is electroplated with a hard, tough, long wearing metal layer.
An object, therefore, is to provide a highly adherent repair by choosing a resin composition that bonds particularly well with the repair area and by selecting the resin, metal particles and quantity of metal particles to produce a hardened resin having a coefficient of thermal expansion substantially the same as the metal surface over the range of temperatures to which the metal surface is to be used.
Another object is to provide a wear surface over at least the repaired area, extending, if desired, over the entire structure operating surface, which will be highly resistant to wear, well exceeding the wear characteristics of the filled resin.
Yet another object is to provide a method of repairing damaged metal surfaces that requires only simple equipment and can be performed rapidly and conveniently.
A further object is to provide a rapid, convenient method for repairing scored or grooved hydraulic cylinder mating surfaces of a piston and the cooperating cylinder wall.
REFERENCES:
patent: 2984895 (1961-05-01), Griffin et al.
patent: 3004336 (1961-10-01), Timuska
patent: 3950571 (1976-04-01), McBride et al.
patent: 4129548 (1978-12-01), McDonnell
patent: 5972423 (1999-10-01), Abbey et al.
Ball Michael W.
Haran John T.
Morkunas Frank G.
LandOfFree
Method of repairing damaged metal surfaces does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of repairing damaged metal surfaces, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of repairing damaged metal surfaces will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2581600