Seal for a joint or juncture – Seal between relatively movable parts – Diverse and distinct dynamic seals
Reexamination Certificate
2002-06-17
2004-04-27
Knight, Anthony (Department: 3676)
Seal for a joint or juncture
Seal between relatively movable parts
Diverse and distinct dynamic seals
C277S402000, C277S407000, C277S560000, C277S370000, C277S565000, C277S571000
Reexamination Certificate
active
06726212
ABSTRACT:
TECHNICAL FIELD
The present disclosure is related to the field of seals for sealing rotary shafts, generally. The methods and apparatus are particularly related to the field of unitary combination lip and sleeve seals. More specifically, this is an improved seal adapted for use in severe duty applications including construction equipment, agricultural machinery, track driven vehicles, and other applications where oil or grease must be held in contact with rotary shaft and bearing assemblies. This seal and other seals of this type must also operate as excluder seals to keep lubricated surfaces free from corrosives, acids, other chemicals, dirt, mud, dust, abrasives, water and other contaminants. Even more particularly, this seal incorporates design features that enhance performance (compared to usual original equipment seals) when installed on shafts that have been slightly damaged by normal wear.
BACKGROUND AND SUMMARY
The present seal structure yields a very important benefit that has eluded other persons skilled in the art. It can be retrofitted to existing, worn machinery to enhance the protection of costly lubricated machine components. This seal can replace existing seals, and the performance of this seal exceeds that of all other standard-sized, commercially available, conventional, lip and sleeve type seals. The only commercially available type of seal with performance comparable to this embodiment is the dual cone face seal. It is known by those in the art that dual cone face shields have disadvantages that significantly restrict their use. The seal disclosed here overcomes the two major inherent disadvantages of dual cone face seals—large size and high cost.
Conventional unitized lip and sleeve seals are much smaller than dual cone face seals. Since this seal can be installed as a direct replacement for ordinary seals, it can be specified and used without making any modifications to the design of a machine. The shaft, the bore, and the housing in which the seal operates are identical whether the present seal or conventional seals are used. Wherever dual cone face seals are desired, the machine must have been originally designed specifically for their use because they are much larger than ordinary seals. They are simply too big to fit all of the machine locations where their superior performance could justify the significant added cost.
The cost of making this seal is only a fraction of the cost of making a dual cone face seal. The additional cost can be substantial because the manufacturing cost for a dual cone face seal is currently between twenty and ninety times the cost of a conventional seal. A preferred embodiment of the present disclosure is expected to be two to three times the cost of a conventional seal.
The most important benefit of the seal now disclosed is that it can create permanently lubricated shaft and bearing assemblies that can withstand severe use. This seal may enable equipment manufacturers to improve the performance of their machinery by reducing maintenance requirements. It is believed that existing vehicles and other machines can be retrofitted advantageously by replacing the original re-greasable seals with this new permanently lubricated seal.
It is an object of the invention to accomplish the foregoing and to teach the structure of a retrofittable severe duty seal for a shaft.
It is a further object of this disclosure to show an embodiment that may be used to seal rotary shafts used in track-driven vehicle tracks.
Another object to provide an embodiment that may be useful in any application where a shaft and shaft bearing or bushing surfaces may be exposed to mud, dust, abrasives, cement, submersion, abrasive liquids or other substances that could damage relative rotary mechanical components.
Another object hereof to disclose a seal that lasts longer than previously known low cost seals that are adapted for use in severe duty applications.
Another object of the present disclosure is to make essentially all of the important benefits of a dual cone face seal available at a much lower cost.
Another object of the present disclosure is to make essentially all of the important benefits of a dual cone face seal available in a physically smaller assembly.
Another object of the present disclosure is to make essentially all of the important benefits of a dual cone face seal available in an assembly having the same physical dimensions as a conventional single lip or double lip seal.
Another object hereof to provide an embodiment that can function as an excluder seal, as a grease seal, as an oil seal, and as a seal for other liquids at low and moderate pressures.
Another object of this disclosure is to provide a seal having a shaft-contacting sleeve that enables the seal to be installed on and to operate reliably with shafts having imperfections such as those ordinarily caused by wear and use.
Another object hereof is to provide a seal that is unitary in structure to thereby improve reliability, and to make installation of the seal easier that would be the installation of a seal that is comprised of two or more separable parts.
Another object is to provide a permanently lubricated seal for the track pins of a track-driven vehicle.
A further object is to provide a seal with sealing elements that include: a main sealing lip with a garter spring, three dust lips that contact the sleeve, one dust lip that contacts the inner surface of the housing, two face dust lips that contact the inner surface of the faceplate, and an elastomeric shaft-contacting faceplate ring.
These and further objects of the apparatus taught in accordance with this specification, the claims, and the appended drawing figures are set forth below.
DISCLOSURE OF THE INVENTION
The present disclosure shows a retrofittable radial lip seal for a circular rotatable shaft comprising a sleeve that may be disposed coaxially around the shaft. The sleeve has an inner end that would normally be in contact with the grease, oil, or other fluid to be contained within a housing, an outer end that would normally be exposed to ambient conditions, a bore that has an elastomeric coating, and a sleeve flange extending radially outward from the outer end of the sleeve and generally perpendicular to the sleeve axis. The sleeve flange is terminated with an outer edge. One or more circular elastomeric face lips extend coaxially from the sleeve flange outer face.
A circular elastomeric perimeter lip extends radially and outwardly from the outer edge of the sleeve flange to contact a generally cylindrical hollow seal case adapted for fitting into a bore, such as a bore that is formed through the wall of a housing, or other securement.
The case is formed from a generally cylindrical case body having an outside surface, or outside diameter, that may be disposed within a bore and in contact with the wall of the bore. An elastomeric coating may be affixed to the outside of the case body. By coating the outside of the metal case body with an elastomeric coating or layer, it is possible for the seal to securely fit a bore that may be worn or slightly damaged through use.
The inner surface of the case is smoothly finished in the region close to the outer end so that it is adapted for maintaining continuous operating contact with the perimeter lip of the sleeve flange. The case has an inner, fluid-contacting end, opposite the outer end. A case skirt extends radially outward from, and generally perpendicular to, the outside end of the case. Although it is believed preferable to form the case skirt from the case body, it may be possible to form the case skirt by attaching a separate piece. A case inner flange is located between the outer end and the fluid end of the case.
The case inner flange extends radially inwardly from, and generally perpendicular to, the longitudinal axis of the inside of the case. It is believed preferable to draw the case inner flange from the material of the case body. When formed in that manner, the material of the case body is doubled back on itself to yield two thicknesses of the case materia
Dorsey & Whitney LLP
Knight Anthony
Patel Vishal
Transcom, Inc.
LandOfFree
Retrofittable severe duty seal for a shaft does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Retrofittable severe duty seal for a shaft, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Retrofittable severe duty seal for a shaft will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3245836