Caster system used with wooden or plastic legs for furniture

Abstract

A caster and leg assembly for supporting a piece of furniture on a floor. The assembly includes a caster affixed within a recessed area formed in the bottom of a wooden or plastic furniture leg to create a strong support for the furniture as well as create a good appearance. The caster has at least one spherical roller supported within the housing to allow the furniture to be readily movable omnidirectionally. With one spherical roller, the weight of the furniture acts at the center of the spherical roller. In one embodiment, there are three spherical rollers located equidistant from the vertical center line of the assembly to support the furniture weight equally by the spherical rollers. A glide can be readily attached and detached from the bottom of the caster and, when attached, the glide cup covers the spherical rollers and presents a flat, planar bottom surface.

Description

REFERENCE TO RELATED CASES [0001] This patent application is a continuation-in-part application based upon and claiming priority of U.S. patent application Ser. No. 10 / 295,666, filed Nov. 15, 2002 and entitled CASTER ASSEMBLY FOR A BED FRAME MEMBER OR FURNITURE and which is, in turn, a continuation of U.S. patent application Ser. No. 09 / 519,725 filed Mar. 3, 2000, now U.S. Pat. No. 6,568,031, issued May 27, 2003.BACKGROUND OF THE INVENTION [0002] The present invention relates to a caster assembly for a use with furniture, and, more particularly, to a caster assembly adapted for use with a wooden or plastic leg of a piece of furniture. [0003] In general, there are many types of furniture casters that are available and which are affixed or incorporated into the legs of such furniture to enable that particular piece of furniture to be readily rolled from one location to another. [0004] Accordingly, the caster assemblies for furniture normally have rotatable rollers to facilitate the mo...

AI Technical Summary

Benefits of technology

[0015] Now, in accordance with the present invention, an improved caster and leg assembly is shown that overcomes the difficulties heretofore explained. In the present invention, the caster assembly is adapted for use with furniture having a wooden or plastic leg. The structure of the caster assembly comprises a housing that is attachable to the wooden or plastic leg of a piece of furniture by interfitting into a recessed area provided in the lower end of the furniture leg. By the interfitting of the caster into the bottom of a wooden or plastic leg, the combined caster and leg assembly can present an overall smooth, streamlined exterior surface as well as maintain the strength of the support for the furniture. As a further advantage, the present caster can be added or retrofitted to an existing furniture leg by an owner of the furniture or can be installed by the original manufacturer of the furniture.

[0016] The assembly has a generally vertical elongated axis or centerline such that the weight of the bed is transmitted to the housing of the caster and leg assembly generally along the centerline that is centrally located with respect to the housing. At the bottom of the caster there is at least one, and preferably three, spherical rollers that contact the floor and allow the piece of furniture roll with respect to the floor for the convenience of moving the furniture from one location to another location. The spherical rollers are mounted to a housing having a cavity and a plurality of small spherical balls are freely located between the housing and the spherical rollers such that each spherical roller or rollers freely rotate omni-directionally, that is, the roller or rollers are free to rotate about center points and thus can rotate in any direction. As such, therefore, the spherical roller(s) can rotate in any direction that the user pushes the piece of furniture in relocating that piece of furniture and no additional force is needed to commence the initial movement of the furniture.

[0017] In the preferred embodiment, there are at least three spherical rollers, more preferably three spherical rollers, so that the weight of the furniture and its supported components and weights are distributed at three contact points with the floor to better distribute the weight and prevent severe indentations in the floor. In addition, the location of the rollers is such that they are equidistant from the elongated, vertical central axis or centerline through which the weight of the furniture acts on the caster and leg assembly and thus, the single bending moment is eliminated and the structure has enhanced strength and stability. As stated, with the three rollers, each is still mounted to a housing such that the rollers move freely in any direction and do not need to be aligned to the direction of movement of the furniture by pivoting about a central axis or centerline. In effect, the need for a swiveling function is completely eliminated.

[0018] Accordingly, the caster assembly of the present invention has the strength of the prior art glide assemblies since the single offset has been eliminated and, of course, the assembly therefore does not need to swivel in order to allow the furniture or bed to be moved in any direction. With the offset and the need to swivel eliminated, the aforedescribed problems associated with those features are also eliminated.

[0019] As a further feature of the present caster assembly, a glide is readily attachable and detachable to convert the caster assembly from a roller caster to a glide function and vice versa. When attached, the glide alters the function of the caster assembly from a roller caster where the rollers are in contact with the floor to a glide function where the caster assembly is transformed into a glide. Accordingly, the bottom surface of the glide is a planar surface as in the case of most glides and the glide is attached and detached without the need for special tools or equipment. It should be noted, that the bottom surface of the glide is referred to as planar, however, typically it is an effective planar surface as there is normally a central portion of the bottom surface that is displaced upwardly and only a peripheral planar area is actually in contact with the floor. The attachment and detachment can be readily accomplished in the home by an installer that can determine at the time of installation whether or not the glide or roller function is applicable.

[0020] The resulting caster assembly therefore combines the strength of the glide assemblies with the mobility of a roller caster assembly and provides the user with the option of using the spherical rollers to contact the floor or easily transform the caster assembly to add a glide so that the assembly can be used on slippery surfaced floors.

Problems solved by technology

The swiveling action or movement is necessary to correctly align the roller for movement in the proper direction, however, such swiveling movement can be generally difficult to accomplish.

With the weight of many pieces of furniture, there is considerable friction acting against the swiveling action of the caster assembly and the problem is aggravated by the need to align some 4-5 rollers in order to roll the furniture.

As such, therefore, while the swivel action is necessary to properly move the furniture, it can be somewhat difficult to get the swivel action to operate easily and thus the initial movement of the furniture is not easy to accomplish, particularly when the piece of furniture is on carpeting with padding.

One of the difficulties with such casters, therefore, is that the bending moment created by that offset creates stress on the caster assembly and can cause a premature failure of the caster assembly or the furniture itself, thereby disabling the entire unit.

In the aforementioned patents, however, while a plurality of members contact the floor and thus allow the weight to be borne by a plurality of elements, there is a further problem with respect to the ease of moving such casters as the spherical members are clamped into the housing supporting the particular piece of furniture and the spherical contact members do not thus freely rotate to allow the ready movement of the furniture.

With such flooring surfaces, the user of a caster having a roller causes unnecessary sliding or rolling as contrasted to the intended use of a rug roller or caster on a carpeted surface where the friction with the carpet reduces the mobility of the roller or caster.

The caster cups, however, are easily displaced from under the roller since they are not firmly locked to or attached to the caster assemblies and are thus difficult to maintain in place when the furniture is moved during the normal use of the furniture.

Thus, over time, the caster cups become displaced with respect to the roller and no longer serve their intended purpose.

As a further problem with many of the aforedescribed caster assemblies, since the caster roller needs to pivot 360 degrees about its vertical axis, it is very difficult to build the caster assembly into a wooden or plastic leg of the furniture and, therefore, the caster for a wooden or plastic leg is simply screwed into the bottom of a leg by means of a threaded stem and, accordingly, creates a weak point as well as a less than pleasing appearance of the caster affixed to the bottom of a leg.

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