Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
2002-10-31
2004-04-06
Hurley, Kevin (Department: 3611)
Land vehicles
Wheeled
Articulated vehicle
C280S511000
Reexamination Certificate
active
06715781
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to trailer hitches of the type commonly used to connect a towing vehicle to a trailer and, more particularly, to a ball hitch assembly having a removable and easily interchangeable ball including structure for preventing the inadvertent disassembly of the hitch.
BACKGROUND OF THE INVENTION
Trailer hitches are devices which connect a tow vehicle to a trailer by means of a ball hitch which is mounted onto the vehicle, or onto a tow bar which is connected to the vehicle. The hitch then mates with a socket located on the trailer tongue. This ball and socket configuration is designed to allow adequate rotation of the socket with respect to the ball so that the vehicle-trailer combination can maneuver around corners. Typically the socket mechanism has a releasably lockable coupling so that it locks onto the ball hitch to prevent decoupling while towing.
There are several standardized sizes of these ball and socket systems, the specific size usually depends on the size of the trailer or its weight and is specified by the outer diameter of the hitch ball. Typical ball sizes are diameters of 1-⅞ inches, 2 inches, 2-¼ inches, and 2-{fraction (5/16)} inches. For a trailer hitch to function properly and safely, it is important that the size of the ball matches that required by the particular hitch socket. Using a ball that is smaller than the size specified for the trailer could have disastrous consequences, and coupling a trailer with a ball that is too large for its socket is impossible. A vehicle may need to tow a variety of trailers, with sockets of different sizes, and hence there is a need to be able to employ different sizes of hitch balls on a vehicle.
Conventional hitch balls consist of a mounting bolt and ball as an integral unit. The unit is bolted onto the tow bar and requires at least one wrench for its removal and installation. This can be inconvenient because it requires that one carry the proper tools in the vehicle, as well as a variety of hitch balls, which can have their threads damaged if not properly stored. Additionally, the hitch ball mounting threads may become corroded or filled with debris so that removing the ball can be a formidable task, especially when trying to change a hitch ball at night in the rain. It is usually not feasible to have multiple, different-sized balls bolted to a vehicle because the ball must be located along the centerline of the vehicle and at a preferred height in order to evenly distribute the loads acting on the vehicle and trailer.
With the purpose of overcoming these problems, several types of hitches, which present other schemes of interchanging balls, have been invented. For example, U.S Pat. No. 4,433,854 issued Feb. 28, 1984 to Smith shows an interchangeable ball hitch in which the ball contains a spring-biased latch that locks the ball onto a mounting piece which is attached to the tow bar and which can be released for interchanging the ball sizes. The latch includes a spring and pin which are integral to the mounting piece. This device requires that the ball be rotated into the proper position for removal which can be difficult if trying to change a ball at night without a flashlight.
U.S. Pat. No. 5,169,168 issued Dec. 8, 1992 to Harry et al describes a hitch ball assembly including interchangeable balls and a mounting post which is attached to the tow bar. The mounting post contains a grooved path and the ball has a pin on the inner cavity of the ball. To mount the ball one must align the pin with the beginning of the groove at the top of the post and then rotate and depress the ball to move the pin along the groove until it has fully seated. Once seated, the ball is free to rotate around the mounting post. The pin can be damaged during towing by the trailer loads if the tolerances of the fit between the ball and post are too large or if the ball binds up in the hitch socket and then applies those extra loads to the post. In these instances a large portion of the trailer forces are being transferred to the vehicle through just the pin.
U.S Pat. No. 5,419,576 issued May 30, 1995 to Van Vleet, describes an interchangeable ball hitch connector which includes an interchangeable ball and a mounting post which is bolted onto the tow bar. The ball has a chamber which the mounting post fits within. Both the ball and the post have holes which are aligned when the ball is in place and through which a locking pin is placed to hold the two parts together.
U.S. Pat. No. 5,871,222 issued Feb. 16, 1999 to Webb describes a detachable ball hitch apparatus which includes a ball hitch with an integral post that fits into the cavity of a piece that mounts onto the tow bar. The post has a spring-loaded pin that slides into a groove in the tow bar piece. When the ball is fully mounted the pin is depressed to lock it into the groove to prevent its unintentional removal. Once installed, the ball is not free to rotate. If the spring should fail, the ball cannot be easily removed from the tow bar. Also, the pin and spring are located inside of the ball so this device would be more expensive than others because each of the interchangeable balls must contain those pieces.
While the above-described structures teach the use of detachable and/or interchangeable hitch balls for towing applications, there remains a need for improved interchangeable hitch ball assemblies. This need manifests in both the need for simplified structures as well as structures that can be manufactured efficiently at a reduced cost. The present invention is directed to providing an improved construction for interchangeable hitch ball systems.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide for an improved tow hitch which includes an easily interchangeable hitch ball and which mates with standard hitch ball sockets.
It is another object of the present invention to provide a new and useful hitch ball and mounting structure that allows easy interchange of hitch balls of various sizes for different towing applications. A further object of the present invention is to provide an interchangeable hitch ball assembly that is easy to manufacture yet which is durable in use.
Still a further object of the present invention which provides for interchangeable hitch balls that can be release and relocked yet readily removed from a tow bar.
Yet a further object of the present invention is to provide a new and useful method for attaching an interchangeable hitch ball element to a mounting element in a towing application.
According to the present invention, then, an interchangeable hitch ball assembly for towing a trailer is provided. The hitch ball assembly generally includes a mounting element that is adapted to be secured to a vehicle and a hitch ball element that is adapted to be secured to the mounting element to define an assembled state. One of the mounting element and the hitch ball element includes a post while the other of the mounting element and the hitch ball element has a cavity formed therein such that the cavity has a threaded entryway and an interior chamber. The post has a threaded head portion with a selected axial head length. The interior chamber is then formed to have a depth greater than the axial head length of the head portion. The threaded head portion of the post may be threadably engaged by the threaded entryway but, the chamber and the entry way are dimensioned such that, when in the assembled state, the head portion resides in the interior chamber. This allows the hitch ball element and the mounting element to be freely rotatable with respect to one another, yet they are prevented from being disassembled from one another by drawing the hitch ball element axially away from the mounting element.
The mounting element is shown to include a base and means for securing the base to the vehicle, such as by a mounting shank. When the post is supposed on the base and the chamber is formed in the hitch ball element, this mounting shank extends co-axially of the post and oppos
Gegick Rebecca A.
Henson Michael R.
Hurley Kevin
Martin Timothy J.
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