The present invention relates generally to the field of small combustion engines with overhead valve or overhead cam configurations. More specifically the present invention relates to a system for covering rocker arms, valve stems, overhead cams, or other engine components extending from a cylinder head.
Overhead valve (OHV) engines include various components to open and close the intake and exhaust valves. Typically, a camshaft includes cams that push tappets at timed intervals. The tappets are coupled to pushrods, and the pushrods engage rocker arms. The rocker arms pivot upon spherical surfaces of a rocker balls, which are positioned on rocker studs and transfer the upward force of the pushrods into downward force on valve stems, and visa versa. Other rocker arms may pivot upon cylindrical pivots, such as pins, that are secured to a cylinder head without rocker studs. As the rocker arms push down or lift up upon the valve stems, the corresponding intake and exhaust valves open and close in the combustion chamber. Often valve springs are positioned around the valve stems to provide a lifting force to return the rocker arms and valves to the closed position when the cam is no longer engaged with the tappet.
The rocker arms and rocker studs are typically fastened to the top of a cylinder head, with the pushrods and valve stems extending through apertures in the cylinder head. The components of the OHV configuration extending from the top of the cylinder head are typically enclosed by a housing. A head plate forms a bottom portion of the housing. The head plate may be integrally formed with the cylinder head, or may be separately attached to bosses extending from the cylinder head. A rocker cover forms a top portion of the housing, attaching to the head plate and limiting access to the rocker arms and other components of the OHV configuration attached to the top of the cylinder head.
One embodiment of the invention relates to a cover system for an internal combustion engine having an overhead valve or overhead cam configuration. The system includes a cover attached to a head plate. The cover has sides extending from a top surface and terminating in a flange with an overhang. The overhang includes a catch. The head plate has sides extending from a bottom surface and terminating in a curl. The flange and the overhang are positioned adjacent to the curl with the catch engaging an end of the curl.
Another embodiment of the invention relates to an internal combustion engine with an overhead valve configuration. The engine includes a cylinder head, an exhaust valve rocker stud with a threaded end, and an intake valve rocker stud with a threaded end. The engine further includes a head plate fastened to the cylinder head with the exhaust valve rocker stud and the intake valve rocker stud. The only threaded fasteners fastening the head plate to the cylinder head are the rocker studs.
Yet another embodiment of the invention relates to an internal combustion engine with an overhead valve configuration. The engine includes a cylinder head having mounting bosses extending from the cylinder head. Also the engine includes two rocker studs and a head plate fastened to the cylinder head via the rocker studs. Threaded ends of the rocker studs are fastened through apertures in the head plate to the bosses. Additionally, the engine includes a cover attached to the head plate without the use of threaded fasteners.
Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims.
The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which:
Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.
Referring to
The engine 110 further includes a crankcase 122 and a corresponding sump 124 fastened to the underside of the crankcase 122. The crankcase 122 supports internal components of the engine 110, such as a piston, a connecting rod, a camshaft, and other components. The sump 124 forms a base of the crankcase 122, and holds a pool of oil lubricant within the crankcase 122. A vertical crankshaft 126 extends from the crankcase 122, through the sump 124. The crankcase 122 and sump 124 may be integrally cast.
Referring to
Referring to
Still referring to
The rocker arms 168, 170 move at different times to transfer force from the pushrods 156, 158, opening and closing an exhaust valve 186 and an intake valve 188, respectively. The head plate 138 has an asymmetrical shape corresponding to the arrangement of the rocker arms 168, 170. However, in other embodiments the head plate 138 may be formed in other shapes and configurations.
Referring to
In some embodiments, multiple fasteners are used to couple the rocker cover 132 to the head plate 138. For example, in at least one embodiment overhang 200 of the rocker cover 132 includes at least two fasteners, each having a catch. The fasteners are positioned on opposing sides of the overhang 200. In another embodiment, the overhang 200 includes at least two fasteners. In some embodiments, the hook or catch is integral with the head plate 138 and is received by the overhang 200. The fasteners, as shown in
A method for assembling a rocker cover system includes several steps. A step includes providing the rocker cover 132, the head plate 138, the cylinder head 130, and the gasket 230. Another step includes fastening the head plate 138 to the cylinder head 130. A set includes coupling the gasket 230, such as a liquid gasket, to the curl 206 or to the flange 198. Yet another step includes aligning the rocker cover 132 over the head plate 138, such that the flange 198 and the overhang 200 are positioned over the curl 206. Another step includes pressing the rocker cover 132 toward the head plate 138 to “snap” the catch of the protrusion 208 into place at an end of the curl 206. No tools (e.g., screwdriver, pliers, wrench, etc.) are required.
The construction and arrangements of the system for covering rocker arms, as shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example the engine is shown with a vertical crankshaft, but it may be configured with a horizontal crankshaft. Also, the engine may include multiple cylinders. In some embodiments, the cover system is used to cover an overhead cam. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. In some embodiments, the system can be used to cover other engine components, such as a filter of an air intake. The order or sequence of any process, logical algorithm, or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.
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