Chair rocker accessory

An accessory provides a chair, having a seat and four legs, with a rocking facility. The accessory includes a pair of rockers, each having a longitudinally curved underside and a furrowed upper side sized to receive the legs. The accessory also has a pair of spaced rungs spanning the rockers. Also included is a strap for encircling the rungs and the seat to detachably secure the legs to the furrowed upper side of the rockers.

BACKGROUND OF THE INVENTION 
The present invention relates to an accessory that attaches to the legs of 
a chair to afford it a rocking facility. 
People who favor rocking chairs often wish to convert conventional chairs 
to rocking chairs. Such conversion may be desired when using a chair away 
from home. Alternatively, a user may only wish temporarily to convert a 
chair into a rocker. 
For this reason, rocker attachments have been proposed as detachable 
accessories for regular chairs. For example, in U.S. Pat. No. 255,104 a 
rocker attachment uses a pair of rockers each having a pair of mortises 
for receiving the four legs of a chair. This rocker attachment is secured 
to a chair by an adjustable hook that connects to the rungs of the chair. 
In U.S. Pat. No. 101,802 mortised rocker attachments are tied around the 
legs and over the rungs of a chair by means of cords and bands. A 
disadvantage with these attachment systems is that stress is applied to 
the joint between the rung and leg and the leg or rung can be damaged or 
defaced. Rungs can be frail and are not normally designed for the 
pressures generated by rocking. 
Other rocker attachments use a curved channel, (see for example U.S. Pat. 
No. 1,367,390) into which the legs of a chair are placed. Still other 
rocker attachments permanently modify a chair leg by driving a screw into 
the leg. See U.S. Pat. No. 1,566,157. Other rocker attachments do not 
drive a screw directly into the leg but employ set screws that apply high 
lateral pressure to the leg which creates a significant likelihood of 
distortion or damage to the leg (see U.S. Pat. No. 1,231,151). Such 
distortion and potential damage to a chair leg is unacceptable for a 
visiting guest using a host's chair. Some attachments have attempted to 
reduce the point pressure on the legs by using wrap-around clamps such as 
pipe clamps. See U.S. Pat. No. 4,126,353. Other leg clamping devices are 
shown in U.S. Pat. No. 138,826; 232,147; 244,104; 315,369; and 406,400. A 
disadvantage with all of these systems is that high stress is applied to 
the tip of the chair leg. Many chair legs are wooden and are not designed 
to sustain the high lateral forces associated with rocking. See also U.S. 
Pat. No. 15,302; 71,357; 72,178; 75,617; and 145,036. 
Accordingly, there is a need for an easily used rocker attachment that does 
not risk damaging chair legs and can be quickly and easily secured to the 
leg of a chair. 
SUMMARY OF THE INVENTION 
In accordance with the illustrative embodiments demonstrating features and 
advantages of the present invention, there is provided an accessory for 
affording a rocking facility to a chair having a seat and four legs. The 
accessory has a rocker assembly including: (a) a pair of rockers; and (b) 
a pair of spaced rungs spanning the rockers. Each of the rockers has a 
longitudinally curved underside and a furrowed upper side sized to receive 
the legs. The assembly also includes a strap coupled to the rocker 
assembly for encircling the seat to detachably secure the legs to the 
furrowed upper side of the rockers. 
By employing such an accessory an improved chair rocker accessory is 
achieved. In a preferred embodiment, a pair of rockers are spanned by a 
pair of transverse rungs that mount into transverse holes through the 
rockers. The chair legs are placed inside furrows atop the rockers and the 
chair is then strapped into place. In one embodiment, a pair of straps 
encircles the transverse rungs and the chair seat to attach the rockers. 
In an alternate embodiment, the rockers have transverse slots. Straps are 
strung transversely through these slots and encircle the chair seat to 
attach the rockers. 
In this preferred embodiment, multiple holes and multiple slots are 
provided so that the rungs and the straps can be placed in adjustable 
alternative positions. Preferably, the rocker is composed of a curved, 
rectangular bar. The curved bar has curved plates on opposite sides. The 
bottom of the bar and the plates are flush but the plates extend above the 
bar to provide a furrow. Preferably, the floor of the furrow is lined with 
a resilient strip of rubber or similar material to provide a slip proof 
surface for the chair legs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, a conventional chair C is shown having a seat 10, back 
12 and four legs 14. The four legs 14 are shown resting atop the rocker 
assembly of the accessory. The assembly includes rockers 16 and 18, which 
have a curved underside and a furrowed upper side. Each of the rockers 16 
and 18 have a plurality of transverse holes 20. In this embodiment each 
rocker has a forward group of three holes and a rear group of three holes, 
although is some embodiments the number of holes per rung may be two or 
some other number. Furthermore, a third rung (not shown) may be inserted 
in an the forwardmost holes 20 to act as a footrest. 
Spanning rocker 16 and 18 are a pair of rungs 22 and 24. Rung 22 is 
inserted in the rearmost transverse hole while rung 24 is inserted through 
the transverse hole that is third from the front. In other situations, 
different holes may be used. Rungs 22 may be slender rods of made of wood, 
plastic, metal or other materials, preferably having some flexibility. 
Flexible rungs are preferred because chair C may have a greater leg to leg 
spacing in front than in back. In embodiments adapted to deal with very 
different leg to leg spacings, the rungs 22 can be a long slender spring 
mounted inside a hollow flexible tube made, for example, of plastic. In 
such cases the rungs 22 can flex to accommodate rockers 16 and 18 when 
they are not parallel. 
Chair C is shown attached to rocker 16 and 18 by a strap assembly in the 
form of a pair of straps 26 and 28. Straps 26 and 28 each have a buckle 30 
and 32, respectively. Buckles 30 and 32 can be used to tighten band 26 and 
28 so that chair C is firmly secured to the rocker assembly. 
Each of the rockers 16 and 18 are shown with a plurality of transverse 
slots 34. Slot 34 provide an alternate means of attaching chair C to the 
rockers 16 and 18. An alternate pair of straps 26A and 26a shown 
encircling seat 10, are strung through a pair of slots 34 and rockers 16 
and 18. Each of the rockers 16 and 18 are shown with seven transverse 
slots 34, although in some embodiments a different number can be used 
instead. For example, four straps per rocker may be preferred in 
embodiments wherein structural strength and rigidity is more important 
than adjustability. Straps 26A and 26B can also have buckles for 
tightening the straps. Instead of buckles, the straps may be elastic and 
therefore automatically adjusts to various sizes of chairs. 
Referring to FIGS. 2, 3, and 4, previously illustrated rocker 18 is shown 
without other components attached to it. Rocker 18 is shown having a 
curved, rectangular bar 36. Attached to the sides of bar 36 are a pair of 
curved plates 38 and 40. Plates 38 and 40 are flush with the underside of 
bar 36 but extend above the top of bar 36 to form a furrow 42. Mounted on 
the furrowed side of bar 36 is a resilient antislip runner 44. Runner 44 
is a strip of rubber but plasticized foam rubber, various plastic 
materials or other antislip material can be used in different embodiments. 
The plates 38 and 40 can be secured to bar 36 by nails, screws, glue or 
other appropriate means. Runner 44 can be secured to bar 36 by staples, 
nails, glue or otherwise. 
To facilitate an understanding of the principles associated with the 
foregoing accessory, its operation will be briefly described. Rockers 16 
and 18 may be placed in a parallel position at approximately the side to 
side spacing between the legs of chair C. Since rungs 22 loosely fit in 
holes 20, the lateral spacing between rockers is easily adjusted. Multiple 
holes 20 are provided to suit the size of the chair. It is preferred that 
the rungs are centered between rockers 16 and 18 to provide symmetry and 
balance. 
Once the rockers 16 and 18 are placed into an approximately correct 
position, chair C can be lifted and placed on top of the rockers as shown. 
The chair C is shown biased somewhat to the front of the rockers 16 and 
18. This provides the conventional orientation where the rockers are 
longer in the back to provide better support for the backward rock when 
the feet are lifted from the floor. The shorter rockers in front are 
adequate since the user can counteract excessive forward rocking by using 
his or her legs. 
With the chair positioned appropriately atop the rockers 16 and 18, straps 
26 and 28 can be wrapped around seat 10 and the rungs 22 and 24. 
Preferably, the are mounted symmetrically about seat 10 so straps 26 and 
28 have the same spacing from the right and left edge, respectively, of 
seat 10. The buckles 30 and 32 can be adjusted to provide adequate tension 
on the straps 26 and 28. 
Some chairs have a solid back which makes the front to back position of 
straps 26 and 28 impractical. In such instances it may be desirable to 
wrap the straps laterally. This orientation is shown by the straps 26A and 
28a, shown in phantom. Straps 26A and 28a are routed through the 
appropriate slots 34 in rocker 16 and 18. Multiple slots are provided so 
that the straps can be moved to suit the size of the chair. As before, the 
straps 26A and 28a are placed symmetrically about seat 10 and are 
tightened to firmly attach rockers 16 and 18 to legs 14. 
The foregoing assembly can be carried in a compact bag so a traveler can 
convert chairs in a hotel and other places into a rocking chair. This 
compact package facilitates transportation of the assembly. 
It is to be appreciated that various modifications may be implemented with 
respect to the above described preferred embodiments. For example, the 
accessory rungs may be threaded into the various transverse holes to 
provide a more rigid attachment. Alternatively, pins, clamps, or other 
fastening means may be used to hold the rungs in place. Also, in some 
embodiments, the straps or bands can be permanently attached to the rungs 
so there is no need for a rung-to-rung length of strap. Similarly, the 
straps can be attached to the rockers directly so that there is no need 
for a rocker to rocker length of strap. Furthermore, the number, position 
and shape of the various apertures and slots in the rockers can be altered 
depending upon the nature of the rungs, the size of the straps, the 
desired capacity of the rockers, etc. In addition, the rockers can be 
formed of one or more units made of plastic, metal, wood, etc., with the 
possible exception of the resilient runner attached atop the rocker. Also, 
the radius of curvature and the shape of the tips of the rockers can 
differ in various embodiments. Also, the top of the rockers need not 
necessarily be curved. Furthermore, in some embodiments, the furrow made 
in the top of the rockers may have a V-shaped floor to hold more snugly 
the chair legs. Also, the ends of the straps may have hooks, snaps, or 
other fastening means to allow attachment to the rungs or the rockers at 
various positions. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is therefore to be understood 
that within the scope of the appended claims, the invention may be 
practiced otherwise than as specifically described.