Caster assembly

A caster assembly comprising caster wheels, a saddle, mounted pivotally on the wheel axis, having a bore in its upper surface which extends therein offset from and perpendicularly to the wheel axis, a first stem, one end of which is mounted in the saddle bore, the other end of the stem extends vertically upward therefrom; a horizontally extending slab is mounted pivotally on the free end of the first stem; a second stem is mounted pivotally, offset from the first stem and the wheel axis, in the slab and extends upwardly therefrom; the free end of the second stem is mountable in the underside of a rollable object.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
My invention relates to improvements in casters, primarily for wheeling of 
furniture, classified under class 16, subclass 18. 
More specifically the present invention concerns a unique construction of 
casters, having a dual level of vertical swivels, interconnected by an 
intermediate member, and mutually offset from one another and from the 
horizontal axis of the caster wheels. 
The advantages of this unique construction will appear more clearly in the 
following detailed description. Among other things the invented 
improvement in casters will permit rapidity of reorientation and rolling 
of, e.g., any piece of furniture, on which the invented casters are 
mounted, to a degree that was heretofore not attainable. 
(2) Description of the Prior Art 
The following U.S. patents were developed, none of which appears to be 
pertinent to applicant's caster construction: 
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U.S. Pat. 
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#474 576 CUTTER (1892) 
#498 297 PEDERSON (1892) 
#3 869 105 DANIELS (1975) 
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SUMMARY OF THE INVENTION 
In addition to what is stated under (c) and (e) above, the present 
invention refers to a construction of casters, having a dual level of 
vertical swivels, which (when attached-e.g., to furniture legs) will 
substantially eliminate the initial heavy rotary movements of caster 
wheels inherent in existing caster constructions. 
The advantages of providing a caster with a two layer system of mutually 
offset vertical swiveling elements are many. The most obvious ones are set 
forth in the following: 
(a) The dual offset swivel system of the invention will greatly reduce 
efforts to initiate the rolling movements, e.g., a chair from a standing 
start, with a resultant effortless reorientation to its next position, 
that is to say carrying out tracking while movement is under way. 
(b) In attaining guide orientation, one will also substantially do away 
with resistance to any catching engagement of the caster wheels with deep 
or soft floor coverings. Thus, present caster construction will eliminate 
or lessen wear or damage to carpeting. 
(c) The caster assembly, according to the invention, will speed up the 
tracking reorientation to the following position of the caster wheels. 
(d) The erratic movements about single vertical axis of the conventional 
type caster with scraping action against carpeting when reorientating the 
caster is totally eliminated, by virtue of the invented caster assembly. 
Thus, it is an object of the invention to provide a caster which 
facilitates the movements of rollable objects from standing positions, for 
easy reorientation into other positions. 
It is a further object of the invention to provide a caster, which will 
reduce the wear and tear of soft floor coverings, over which it rolls. 
It is still a further object of the invention to provide a caster, which, 
while simple and inexpensive to manufacture, will be of sturdy 
construction, giving years of reliable service.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the drawings like reference characters designate similar parts in the 
several views. 
Referring now in detail to the drawings, numeral 10 of FIG. 1 designates 
the caster assembly in its entirety. 
Floor engaging means, e.g., a pair of wheels 12a and 12b are interconnected 
by means of axis 14, the ends of which are mounted rigidly, by any 
appropriate means, in central holes 16, respectively, of wheels 12. The 
wheels 12, preferably constitute solid disks, made of metal or sturdy 
plastic. 
A supporting member, e.g., saddle 18, is threaded on and turns freely about 
axis 14, between wheels 12. 
The saddle 18 may, preferably consist of a polygonally shaped solid block 
made of metal, or sturdy plastic material. 
When caster assembly 10 is mounted, e.g., to a leg of a chair and rests on 
the floor, the top surface portion of saddle 18 is provided with a bore 
18a (preferably 11/4" deep), the lower part of which (indicated by broken 
lines in FIG. 1) is internally threaded to receive and retain a vertically 
extending and pivotally connecting means, e.g., first stem 20 
correspondingly being externally threaded at its lower end. 
An intermediate member, e.g., a horizontally disposed slab 22 is provided, 
at one of its ends (FIG. 2) with a first vertically extending bore 22a, in 
which the other end of stem 20 is mounted for pivotal connection with slab 
22. The slab 22 preferably consists of a substantially rectangular solid 
piece of metal or sturdy plastic material. 
Thus, the upper portion of stem 20 is carrying slab 22. 
The pivotal connection (not shown) between stem 20 and slab 22 may be 
established in that stem 20 runs in a bearing, for example, a conventional 
ball bearing with an inner and outer race, the inner race being fixed to 
the upper part of stem 20. 
One could also provide the upper portion of stem 20 with an annular groove, 
in which is disposed a resilient protruding split ring. The bore 22a in 
slab 22 (into which stem 20 is received) then would have a corresponding 
groove into which, on insertion, the initially compressed split ring will 
be forced, for subsequent expansion and holding of stem 20 and slab 22 in 
pivotal but firm assembly. 
The above indicated alternatives are not illustrated in the drawings, or 
described in great details, as being part of well established prior art 
for pivotal connections. 
A second bore 22b is disposed in slab 22 at the end opposite that of bore 
22a, and receives a second pivotal means, e.g., a second stem 24, 
extending vertically upward from slab 22. The pivotal connection (not 
shown) between second stem 24 and slab 22 may likewise be constituted by a 
ball bearing or a resilient deformable split ring, to pivotally 
accommodate the stem and slab, as explained above. 
The upper portion of second stem 24 is provided with a circumferential 
groove, within which a resilient split ring may also be mounted to be 
received by a socket or bore, e.g., in a chair leg (not shown), the latter 
being provided with a corresponding groove for engagement with the split 
ring and pivotal connection therewith. 
Obviously, stem 24 could be mounted in a chair leg (or any object to be 
rolled) by any other appropriate means. 
One could, obviously substitute a caster assembly having one single wheel 
for the above described two-wheel caster construction in which case saddle 
18 should be modified to a forked member, within which a single wheel is 
rotating on an axis extending within the bifurcating portion of the 
modified saddle. 
The gist of the invention is that the present caster assembly is furnished 
with a dual level vertical swivel system disposed mutually offset from one 
another and from the wheel axis. 
As noted above many practical advantages are derived from this unique 
caster construction, in particular that some swiveling motions may be 
carried out by, e.g., a piece of furniture without initially actuating the 
caster wheel axis, thus facilitating subsequent reorientation of the 
wheels to new positions of the furniture piece; this will also prevent 
unnecessary scraping of floor coverings over which the wheels roll. 
While the foregoing has illustrated and described what is now contemplated 
to be the best mode of carrying out the invention, the latter is, of 
course, subject to modifications without departing from the spirit and 
scope of the invention. 
Therefore, it is not desired to restrict the invention to the particular 
constructions illustrated and described, but to cover all modifications, 
that may fall within the scope of the appended claims.