Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
2002-03-29
2004-08-31
Morris, Lesley D. (Department: 3611)
Land vehicles
Wheeled
Articulated vehicle
Reexamination Certificate
active
06783144
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to the towing field and, more particularly, to a spring-loaded interchangeable hitch ball assembly which allows an operator to quickly and conveniently change from one size towing ball to another in order to meet the needs of any particular application.
BACKGROUND OF THE INVENTION
The use of a ball joint coupling comprising a towing ball and cooperating socket assembly in order to tow a trailer behind a towing vehicle is well known in the art. Such an arrangement provides the necessary freedom of movement to allow a trailer to track smoothly behind the towing vehicle while also providing a dependable connection.
Over the years, towing balls of various diameters have been used for this purpose and several industry standard sizes (e.g. 1⅞ inch, 2 inch, 2¼ inch and 2{fraction (5/16)} inch in diameter) are now in frequent use. As a result, it is not uncommon for a single towing vehicle to be used to tow various trailers where those trailers are equipped with socket assemblies adapted for operative connection with towing balls of different diameters. Thus, a need is identified for a hitch ball assembly allowing easy and convenient interchange of towing balls of different diameters so that the hitch of the towing vehicle may be tailored to fit the socket assembly of the trailer to be towed and thereby meet application needs.
Toward this end, a number of approaches have been proposed in the past. Representative of the interchangeable hitch ball art are U.S. Pat. No. 4,433,854 to Smith, U.S. Pat. No. 5,419,576 to Van Vleet, U.S. Pat. No. 5,116,072 to Swenson and U.S. Pat. No. 4,522,421 to Vance.
The Smith '854 patent discloses a post for a towing ball incorporating a spring-biased latch pin for releasably attaching the towing ball to the base. The Van Vleet '576 patent discloses a post and towing ball secured together by means of a fastening pin. While the approaches disclosed in these patents provide secure connection of the towing ball to the post, the latch pins prevent rotation of the towing ball relative to the post. Such rotation is desirable as it minimizes binding forces and promotes articulation and smooth trailer tracking at both highway speeds and when maneuvering slowly in confined areas.
The Swenson '072 patent discloses an interchangeable hitch ball assembly including a post having an annular groove. The towing ball is secured to the post by means of an offset pin which extends tangentially through the annular groove so as to allow relative rotation of the towing ball on the post. There, however, is some difficulty in effectively securing the pin in position and the structure proposed in the Swenson patent for this purpose is relatively expensive to produce.
The Vance '421 patent discloses an interchangeable trailer ball assembly incorporating a mounting post including a threaded stem, a base, an axial bore and a pair of laterally extending bores. A tapered plunger is received in the axial bore. The plunger is biased by means of a spring into a position wherein ball bearings are forced outwardly into engagement with an annular groove or race in the towing ball thereby locking the towing ball in position on the post. An actuator rod may be extended into the axial bore to engage and lift the plunger so as to release the ball bearings from the groove or race and allow removal of the towing ball. While effective, significant user inconvenience may result as the user may need to stoop or lay on the ground in order to fish the actuator rod up through the axial bore which opens toward the ground. This can be a particularly disturbing problem if the ground is wet and/or muddy.
A need is therefore identified for an improved interchangeable hitch ball assembly.
SUMMARY OF THE INVENTION
The advantages and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
In accordance with the purpose of the present invention as described herein, an improved hitch ball assembly is provided. The hitch ball assembly may be broadly defined as including a post and a towing ball carried on the post. At least one displaceable locking element is also carried on the post in either (a) a first position free of securing engagement with the towing ball or (b) a second position in securing engagement with the towing ball. Further, the assembly includes a plunger carried on the post. The plunger includes at least one channel for engaging and receiving the at least one displaceable element.
Still more specifically defining the invention, the hitch ball assembly may include a towing ball having a mounting aperture and an annular race in communication with the mounting aperture. The assembly also includes a post having a base, an axial bore and at least one opening in communication with the axial bore. In a typical arrangement, two opposed openings are provided.
The hitch ball assembly further includes a ball bearing received in each of the openings. Further, a plunger is provided including at least one J-shaped channel. The plunger is carried in the axial bore of the post. Additionally, the hitch ball assembly includes a spring received in the axial bore and engaging an end of the plunger. The spring functions to bias the plunger into a first position.
More specifically describing the invention, the plunger includes a J-shaped channel for receiving each ball bearing. Each J-shaped channel includes a cavity at a first end. When the plunger is biased by the spring into the first position, the ball bearings are aligned with and received in the cavities. In this position the ball bearings are received more fully within the post and therefore are free of securing engagement with the towing ball. Thus, the towing ball may be removed from or installed on the post in this position of the plunger.
In accordance with additional and more specific aspects of the present invention, the post further includes a threaded mounting stem depending from the base. It is this mounting stem that allows the post to be secured to a hitch bar, tow bar, ball mount head or the like. Additionally, the post is tapered to aid in the securing and removing of the hitch ball on the post.
Still further, the towing ball includes a circular opening in communication with the mounting aperture and the plunger includes a slotted head. With the hitch ball mounted on the post, the slotted head extends through the circular opening so as to be engageable by a tool which may be manipulated to rotate and thereby displace the plunger between the first position, allowing installation or removal of the towing ball, and a second position wherein the plunger forces the ball bearings to project further from the post and engage the annular race in the towing ball. This functions to secure the towing ball to the post while allowing the towing ball to rotate freely on the post. It should also be appreciated that the edges of the post defining the openings around the ball bearings are staked so as to prevent the ball bearings from falling out of the post when the towing ball is removed.
Still other features of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.
REFERENCES:
patent: RE19904 (1936-03-01), Donaldson
Lindenman Thomas W.
McCoy Richard W.
Cequent Towing Products, Inc.
King & Schickli PLLC
Morris Lesley D.
Royal, Jr. Paul
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