Tools – Wrench – screwdriver – or driver therefor – Spanner
Reexamination Certificate
1999-05-26
2001-07-17
Morgan, Eileen P. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Spanner
C081S177600
Reexamination Certificate
active
06260451
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to tools. Stated more particularly, disclosed herein is a tool for removing and installing an oil plug of an internal combustion engine.
BACKGROUND OF THE INVENTION
Internal combustion engines of the type used to power lawnmowers and the like typically employ motor oil as an internal lubricant. The oil is retained in an oil reservoir that forms a part of the engine body. Typically, the oil reservoir is sealed off from the environment by an oil plug. The plug typically comprises a threaded plastic cap with a set of plastic protrusions extending outwardly therefrom. The protrusions act as a means for enabling an engaging and rotating of the oil plug during installation and removal of the oil plug.
Unfortunately, oil plugs typically are located in close proximity to the main body of what may be a searingly hot engine. Furthermore, oil plugs often are disposed in confined areas of the engine where they are blocked by elements of the engine, by equipment shrouds, and by related structures. As a result, one attempting to manipulate an oil plug, whether during installation or removal, often risks being burned while attempting to remove or install a small, disadvantageously located plug. Yet a further difficulty derives from the fact that an oil plug can require relatively significant torque to remove after being secured in place for an extended period of time during adverse conditions. This undesirable situation can be exacerbated still further when a sticky, oil-covered plug slips from a user's grasp only to fall onto the ground or onto the dirty engine. With this, it becomes clear that manipulating an oil plug can be a cumbersome and frustrating process.
Of course, it is conceivable that one could use a pair of traditional pliers or the like to attempt to remove an oil plug. However, doing so without dropping or damaging the plastic plug is less than simple or convenient. Advantageously, the prior art has disclosed a number of tools designed for removing an oil plug from an internal combustion engine. For example, U.S. Pat. No. 5,214,985 to Rinehart discloses an adapter that attaches to a standard socket wrench. The adapter comprises a disc that has cylindrical female post holders for engaging standard oil plug protrusions in a male-female relationship. Unfortunately, maneuvering a standard socket wrench within the confines typically encountered when working on an internal combustion engine can be a difficult and time-consuming task. Also, tool heads that attach to a standard socket wrench present the user with the disadvantage of accidental overtightening of the oil plug. Since a typical oil plug and the protrusions contained thereon are typically formed from a plastic material, the protrusions are susceptible to being damaged or completely shorn off by overtightening. Obviously, if the protrusions are damaged or shorn off, the task of removing the oil plug becomes complicated, leading to a needless waste of time and energy on the part of the user.
A further prior art device is disclosed in U.S. Pat. No. 4,351,075 to Pittard, Jr. wherein crossed slots engage oil plug protrusions, and still another tool is set forth in U.S. Pat. No. 4,252,037 to Raine wherein the laterally-engaging wrench has a tool head with a series of openings therein for engaging the protrusions on an oil plug. Grooves guide the protrusions into the openings to provide the wrench with a ratchet-like ability. These devices are said to improve a user's ability to remove and tighten an oil plug by improving contact between the tool head and the oil plug. Unfortunately, these prior art inventions each engage oil plugs laterally with a rigid elongate member that does not provide any degree of flexibility or improved access to hard-to-reach oil plugs. Further, with these and similar devices, oil plugs are not retained by the tool head whereby they tend to fall from the tool head once removed from the engine. With this, oil plugs can fall back toward the hot motor and outside the reach of the user.
With these deficiencies in mind, it becomes apparent that an invention would be useful that could present a solution to the problem of accidental overtightening while also providing improved access to hard-to-reach oil plugs. Similarly, a device providing a means for gripping and retaining an oil plug during engine service while further providing improved access to the work area also would be advantageous. With this, it is particularly apparent that an oil plug tool providing a solution to each and every one of the aforementioned problems while providing a number of heretofore-unrealized advantages would represent a marked advance in the art.
SUMMARY OF THE INVENTION
In light of the above-described state of the prior art, a few objects and advantages of the present invention are worth particular mention. For example, it advantageously is a principal object of the present invention to provide an oil plug tool that is particularly adapted for use on internal combustion engines. The invention is also intended to provide rapid and efficient recovery of an oil plug by exhibiting improved frictional contact between the tool head and the protrusions of an oil plug. Another object of the invention is to provide a tool head that decreases the likelihood of premature disengagement of an oil plug from the tool head following extraction of the oil plug from the oil reservoir. The invention also strives to provide an oil plug tool with axial flexibility for providing improved access to difficult-to-reach oil plugs. A further object of the invention is to prevent accidental overtightening of an oil plug. Still further, preferred embodiments of the invention are designed to provide a tool head that can remove oil plugs with protrusions having atypical configurations. Certainly, these and other objects and advantages of the present invention will become obvious to one who reads this specification and reviews the accompanying drawings and to one who has an opportunity to make use of an embodiment of the present invention.
In accomplishing the aforementioned objects, the present invention for an oil plug tool essentially comprises a handle, a drive shaft, and a tool head. The handle is coupled to a first end of the shaft. In preferred embodiments, the handle is crimped to the first end of the shaft. The preferred drive shaft comprises an elongate, axially flexible member, which may comprise an unsupported, bi-directional, helically wound wire shaft. The axial flexibility of the drive shaft facilitates the use of the oil plug tool in situations where one has limited access to an oil plug.
A still more preferable embodiment of the invention will further comprise a means for limiting torque transmission between the tool and an oil plug to be engaged in at least one rotary direction whereby the tool prevents excessive tightening and associated damage to an oil plug to be engaged. Ideally, the means for limiting torque transmission will be bi-directional whereby torque is limited in both rotary directions. Further, the means for limiting torque transmission will prevent torque transmission above a pre-determined maximum value beyond which the shaft will experience a torque overload. Where the shaft comprises a helically wound wire shaft, torque overload will produce a kinking of the shaft, which will prevent accidental overtightening and potential damage to an oil plug.
The tool head is coupled to a second end of the drive shaft, preferably by crimping. Naturally, the tool head can assume a multitude of embodiments. In preferred embodiments, the tool head comprises at least one cavity defined by a first engaging wall with a peripheral surface disposed in opposition to a peripheral surface of a second engaging wall. With this, there may be a single cavity with a first end defined by the peripheral surface of the first engaging wall and a second end defined by the peripheral surface of the second engaging wall. Alternatively, there may be a first cavity defined by the first e
Danganan Joni B.
Morgan Eileen P.
O'Connell Law Firm
LandOfFree
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