Patent Application
20070129190
The invention relates to inspection cover plates and fill plugs for motorcycles and other low or non-pressurized gearbox or chain drive enclosures requiring side panel access for checking fluid levels and adding materials.
In some motorcycle drive systems, the engine crankshaft is connected to a manually operated clutch via a chain drive. The drive chain is trained around a drive sprocket on one end of the crankshaft and a driven sprocket carried by the clutch. The chain and sprocket assembly is located within primary drive housing at the lower end of the engine. The lower line of the chain is typically immerged in an oil bath contained within the housing, for lubrication. The housing has a main cover enclosing the outboard side of the chain and sprocket assembly. The main cover generally has an access opening that is normally covered by an inspection cover or plate, which is secured with a gasket to the main cover by several screws or similar fasteners to prevent leakage of the oil.
The oil level must be maintained, and the oil changed periodically, in order to avoid damage to the chain and sprocket assembly. In most cases the original equipment design requires that the inspection cover or plate be removed when adding new primary oil. Upon completion of the primary oil change this inspection cover or plate is then secured with a new gasket to the main cover by the same several screws or fasteners to prevent leakage of the oil.
It is known in the art to incorporate a filler plug in the cover plate, both as original equipment and as an after-market accessory to the motorcycle. After-market accessories such as an improved inspection cover and fill plug assembly are highly desirable in some market segments as either or both a functional or esthetic improvement to the original equipment cover plate.
Motorcycle engines and enclosed drive systems are not alone in needing a conveniently accessible port on an exposed side of the machine or device in the form of a robust side cover plate and plug for filling an enclosed but basically non-pressurized case containing moving parts, for inspection, checking the fluid level and adding a lubricating or cooling fluid or other additives or materials to it.
There is a need to address problems such as ease of installation of the inspection cover plate, ease of use of the fill plug feature, leakage of oil or fluid at the edges of the cover and/or the plug seal, strength of design of the cover and fill bore structure, ease of removal and installation of the plug, and integrity of plug seal from infiltration and/or leakage and from loosening during vehicle operations or vibrations from any source.
One embodiment of the present invention provides an aftermarket inspection cover accessory for selected motorcycle makes and models, having an inspection cover plate incorporating an outward and upward angled fill spout with a particularized bore detail, and a mating plug, the spout and plug having a particular closure and multiple O-ring sealing mechanism. The inspection cover is configured to fit the standard inspection access opening of the chain and sprocket assembly main housing, using the same or similar size gasket. It is configured with holes matching the threaded mounting holes that are normally provided for screw-type fasteners around the periphery of the access opening in the main housing.
The thickness of the aftermarket cover plate in the area of the holes is limited to the extent that the same fasteners used in the original equipment cover plate and gasket can be used to install the aftermarket cover plate and gasket, although a thicker or thinner cover plate and alternative gaskets and fasteners may be required for other embodiments. Other variations of the invention may include an original equipment main housing or aftermarket main housing incorporating the spout and plug of this or other embodiments of the invention.
The cover plate, spout and plug assembly may be fabricated of and finished with various materials, by various means, including but not limited to such materials as steel, aluminum, other alloys, composites, or plastics, using fabrication means including any of machining, forging, molding, casting, gluing, or welding techniques, and chrome or paint or other surface or full body treatments or surface finishing techniques.
The fill spout has a linear axis and bore that extends upward and outward from a lower opening in the substantially vertical plane of the inside surface of the inspection cover, to the mouth of the spout. The mouth of the spout is planar and oriented normal to the axis of the bore. The axis of the bore is angled outward at about 60 degrees, plus or minus a few degrees from the vertical plane of the exposed side of the housing, and slightly forward of vertical as viewed from the side, although it may be vertical or inclined slightly rearward from this perspective.
The mouth of the bore is sufficiently large for adding fluid to the fluid reservoir within the main housing by pouring or by use of a funnel. The diameter of the bore in this embodiment is about 1ΒΌ inches, but it may be somewhat larger or smaller.
The lower or inner end of the bore terminates at the inner face of the cover plate within the periphery of the gasket. The intersection of the circular spout wall structure and the cover plate is configured with sufficient material around the circumference of the spout wall to assure adequate strength and fitness for the intended use.
A non-vented fill plug is provided for capping the spout by insertion in a sealing manner into the bore. The fill plug has a top end with a larger diameter knurled surface for gripping; a flat underside to the top end section that mates to the flat face or mouth of the spout, a straight shaft section with a tapered lower end terminating in a flat bottom end, sized to fit easily within the bore. There is an upper O-ring seat milled into the flat underside of the top end section, and a lower O-ring seat milled into the straight shaft section, with an O-ring installed in each of the ring seats. It will be noted that the upper O-ring has a downward facing plane of exposure, and the lower O-ring has an outward facing circular area of exposure.
The flat brim or planar face at the mouth of the spout intersects a chamfered or slightly tapered bore entry section leading into a bore section of uniform diameter. The taper eases the insertion of the lower O-ring of the filler plug into the bore. An O-ring gripping groove or recess is let into the sidewall of the bore at a suitable depth from the mouth or face of the bore. This bore wall recess acts as a circular detent in the bore wall for capturing the lower O-ring on the filler plug when it is fully inserted in the spout.
The bore section of a uniform first diameter continues below the detent to a first point of intersection with the inner surface of the cover plate. The bore has a reducing diameter tapered shoulder section that intersects the inner surface of the cover plate. The tapered section may terminate in a uniform smaller diameter section of the bore, as in this embodiment, which intersects the inner surface of the cover plate and completes the definition of the bore opening in the inner surface of the cover plate. The tapered section of the bore roughly corresponds, with clearance, with the tapered shape of the plug end.
One benefit of the tapered bore section beginning at about the first point of intersection of the larger bore diameter with the inner surface of the cover plate is that the acute outward angle of the spout in combination with the tapered bore section assures that there will be more material in the area of the underside of the junction of the spout with the cover plate, not withstanding the use of a fillet of uniform radius being used around the full circumference of the spout at its intersection with the cover plate. As will be readily apparent to those skilled in the art, the top side of this junction of spout and cover plate enjoys an acute angle of intersection where a fillet of the same radius has a larger cross section area of material.
A characteristic of this tapered bore geometry is a bore hole in the cover plate that is an intersection of a non-uniform bore diameter with the inner surface of the cover plate.
When the plug is fully inserted into the spout, the exposed surface of the upper O-ring contacts the mouth of the spout in an axially compressive sealing manner at the same depth that the lower O-ring is engaged in the bore wall detent in both a radially compressive sealing manner, and in an axial shear pressure sealing manner that places the plug slightly in tension and supplies a continuous compressive force on the upper O-ring as between the mouth of the spout and the plug.
The plug is simply pushed in to the filler spout until it is seated as described, forming a dual O-ring seal against oil leakage and a position retention force or feature that assures the plug will remain in position. For removal, the knurled cap of larger diameter provides adequate leverage for manually pulling the plug out of the spout, with a twisting motion if desired to facilitate breaking the seal and compress the lower O-ring sufficiently against the shoulder of the lower O-ring detent to release the plug.
The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.
The description below is illustrative of but not exhaustive of the many embodiments within the scope of the invention.
Referring to
The fill spout 02 and plug 03 permit easy inspection of the oil and oil level, and changing of the oil level within the housing. The cover plate 01 may have many shapes, and may be flat or have a simple or a complex curvature in order to fit the available opening in the housing and provide an ergonomic shape and projection of the fill spout for easy access from the side of the motorcycle. The housing in some embodiments may require modification to accept the desired aftermarket cover plate. In other embodiments, the cover plate may require modification to fit the available opening in the housing. In other embodiments, the original equipment housing or an aftermarket housing may incorporate the spout and plug of this or a similar embodiment.
The method for fastening the cover plate to the housing may be the same as the original cover plate it replaces, such as by using the same gasket and the same fasteners in the same holes; or it may be different, using a different gasket and different fasteners or a different fastening mechanism. The materials of which the cover plate and fill spout may be fabricated are numerous, including metal, metal alloys or plastic or such other materials as are suitable to the temperature, pressure, stress of usage, and environmental requirements. The method of making the rigid components is not limited and may include any or a combination of casting, molding, and/or machining. The manner of materials treatment and surface finish may vary accordingly. O-rings, which are inherent to one aspect of the design, are a well understood technology for their compressive and sealing characteristics, and need no elaborate description or specification here, whether for motorcycles and chain drive enclosures or such other applications and fluids as to which the invention may be readily adapted.
It should be noted for context that an O-ring is a generic term for a elastic device in the form of a circular ring that typically, but not necessarily, also has a circular cross section. Other cross sections such as square or semi-circular or otherwise may be perfectly acceptable, depending on the manner of use. For example, an O-ring of other than fully circular cross section may be used in any or all of several modes: a compression mode under pressure applied in a vertical (normal to the plane of the ring) direction; a compression mode from radially inward forces; or an expansion mode from radially outwardly acting forces from within the ring's diameter. Where an O-ring is subjected to a sliding contact with another surface to reach its intended seat, it is normally preferred but not necessary to have a circular profile or cross section in so far as the exposed surface is concerned. For example, the inner diameter is a sliding surface when an O-ring is being slid over and along a shaft. The outer diameter is a sliding surface when a shaft with an O-ring seated in a retention groove on the shaft is slid through a tubular structure or bore. Depending on the surface condition and available lubrication, a rectangular cross section may perform adequately. And in the case of an axial load, there may be no sliding action required at all. For purposes of this specification and the claims that follow, an O-ring is not limited to a circular cross section.
Referring to
Referring to
Referring to
Referring to
Referring to
It will be apparent from
Referring back to
Referring again to
Other and numerous embodiments are within the scope of the invention. For example, there may be an extended spout and bore with additional O-ring locking grooves, and mating plugs with longer shafts and multiple lower O-rings suitable spaced to match the locking grooves. There may be a rotationally capable threaded cap on the plug, and external threads on the spout, that permit the plug to be secured and removed by rotation of the cap. This or a conductive chain or cable connecting the plug to the spout or housing may provide an electrical ground connection where appropriate. The reduction in diameter of the bore in the region of angular intersection with the cover plate may be smoothly transitional rather than sharply defined as illustrated, so long as the effect of adding material in the underside area of the spout and cover plate junction is achieved.
As another example, referring again to the figures, there may be a drive chain inspection cover plate, fill spout and fill plug assembly for motorcycles that includes a cover plate configured with a fill spout and adapted to fit an inspection port in a drive chain housing so as to be oriented in a substantially vertical plane with the fill spout projecting outward and upward from the cover plate. The spout may have a mouth and a bore though which fluids may be passed, with the bore extending through the cover plate at an angle other than normal and terminating in an exit hole on the backside of the cover plate. The bore has a first region of relatively larger diameter proximate the mouth of the spout and a second region of relatively reduced diameter proximate the exit hole. The bore has an O-ring locking groove recessed in the wall of the bore in the first region.
There is a fill plug with a top section and a shaft section, where the top section has a larger diameter than the shaft section and is configured with an upper O-ring exposed axially downward from an O-ring retention groove in the underside of the top section for making sealing contact with the mouth of the fill spout, and a lower O-ring exposed radially from an O-ring retention groove on the shaft section for making locking and sealing contact with the locking groove in the wall of the bore. The O-ring locking groove is spaced from the mouth of the spout such that the upper O-ring is held in compression against the mouth of the spout by retention of lower O-ring in axial tension in the locking groove when the plug is fully inserted into the spout. The first region of the bore may have a slightly flared or tapered entrance to a uniform diameter, to ease installing the fill plug and its lower O-ring. The second region of the bore may have a conical section and a terminal section of relatively smaller uniform diameter than the first region, where as illustrated in the figures, the conical section connects the first region to the terminal section. The profile of the exit hole may be defined by the intersection of the conical section and/or the terminal section, and the backside of said cover plate.
The shaft section of the fill plug may terminate as in
As still another example of the further scope of application of the invention, there is a side access fill spout and fill plug assembly for access to a fluid container, consisting of a substantially vertically oriented wall component of a fluid container configured with a fill spout projecting outward and upward from said wall component, where the spout and plug have the same characteristics described above and illustrated in the figures. The container may be a housing for mechanical parts partially submerged in a fluid bath, such as a motor housing or a drive train housing or other enclosure of moving mechanical parts operating partially submerged in a fluid lubricant or coolant. The container may be any enclosure partially filled with fluid, for which direct and easy access is required for checking the level and condition of the fluid and adding or removing fluid if needed. The fill plug may be flexibly electrically coupled to the wall component as by a wire or grounding strap, snap or cap or other permanent or manually actuated connecting means in applications where the electrical isolation provided to the fill plug by the O-rings may be a disadvantage.
The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
This application relates and claims priority to pending U.S. application Ser. No. 60/726,961, filed Oct. 14, 2005.
| Number | Date | Country | |
|---|---|---|---|
| 60726961 | Oct 2005 | US |
