3. (A) Background of the Invention
1. Field ot thB Invention
The present invention relates to an improved base for walking sticks and crutcheS/ which are targeted for aged persons and physically handicapped persons. The invention is in the field of mechanical engineering / mechanical sciences and more particularly relates to the area of technology relating to human rehabilitation engineering.
2. Description of the prior art
Various sorts of sticks/ crutches have been well known so far and almost all of those sticks are equipped with an elastic base formed of materials such as rubber etc. on the lowermost end of the stick. Various improvements to the basic crutch/ stick base have been suggested over the years. In the process base has become complex by adding various components.
US Patent to Pratt, No. 960, 700 and US Patent to Smith, No. 3,040,757 relate to disc like inserts at the inner bottom surface of the crutch base, protecting the rubber-like bottom

of the base from wear due to frictional forces created by the tilting of the crutch end.
US patent to T F- Urban, 3741226_,^is relates c to an improved base with a cup-shaped insert. The insert provides a recess for receiving the crutch end. As the crutch tilts during use, the insert will spread the pressure downward and sideway to the large enlarged portion of the base.
US Patent to Lafayette, No. 2,910,995 relates to an improved crutch tip with a suction grip, which automatically breaks the suction when the crutch is relieved of pressure. US Patent to Yamamoto, et al. No. 637 4841 Bl incorporates a coil spring to provide swirling action of the stick.
3. Problems with prior art
In the crutch/ walking stick bases so far existing, especially US Patent Nos. 3,741,226 and 3,040,757, the vertical neck is subject to extensive flexure, resulting in the premature failure at junction resulting in the limited life of the base and the need for frequent replacements. Also the inside wall of the cavity

where the stick is inserted is provided with gripping lands/ corrugations to ensure firm holding of the base with the stick/ crutch. This only serves to enhance the manufacturing complexity.
In US Patent No. 6,374,841^Bl, where a coil spring may be incorporated to provide swirling action of the stick, this again increases the manufacturing complexity. Also if there were any ingress of moisture during use, it would lead to corrosion, if the spring were made of steel. Because the parts of the base like the insert, metal disk, spring, etc. are reinforced (embedded) , damage to any one of them will lead to the replacement of constituent part the entire base and independent replacement is not possible. Even in the case of US Patent Nos. 3,741,226 and 2,910,995 independent replacement is not possible. Also crutch gripping lands and grooves have to be specially fabricated thus increasing the complexity of manufacture.
It is therefore desirable to have a crutch
base with increased durability and also which
simplifies the manufacturing process of the
same.

(B) Sxuomary of the Invention
The object of the invention is to provide an improved base, which is simple to manufacture with increased durability by reducing the excessive flexure and fatigue in the base.
These and other objects of the present invention are achieved by providing for an improved stick/ crutch base consisting of a crutch gripping land which is an extension of the tubular shaft/ stick of the crutch/ walking stick. The base is preferably of an elastomeric material. Clearance (5'^ is provided between the inside wall of the cavity of the said elastomeric base and the shaft/ stick. At the bottom end of the stick/ shaft 1 a spherulitic insert 6, which is preferably of a polymeric material, is fixed. This spherulitic insert acts as a ball in the proposed ball and socket base. The said ball and socket mechanism comprises of the spherulitic insert allows the stick/shaft to oscillate freely within the clearance 5 during use. Resulting in the lesser flexural stress at the junction of vertical neck 3 and the enlarged base 4 of the elastomeric base. And also facilitate to maintain sufficient contact

between base and ground to provide better traction.
Inner flat bottom surface of the base 11 is reinforced with a circular disc, preferably made of metal, which will come in contact with the bottom surface 12 of the spherulitic insert. Thus preventing the wear of the inner elastomeric bottom surface 11 due to rubbing action between the spherulitic insert and the base resulting from repeated tilting action of the stick during use. This results in increased life of the elastomeric base. The said circular disc 7 also evenly distributes the load from the stick/ shaft throughout enlarged bottom 4 of the base. The bottom of the base is provided with concentric ridges and grooves, facilitating gripping of the ground. This tread has an appropriate combination of grip and traction.
The base, the spherulitic insert, are designed and fabricated in such a way that each can be replaced independently. The base offers reliable service over long period of time.

(C) Brief Description of the Drawings
Fig. 1 is a front elevational view of the
walking stick incorporating the base;
Fig. 2 is a central vertical section of the base
without the walking stick / crutch;
Fig. 3 is a view similar to Fig.2 with a walking
stick/ crutch end inserted and in a vertical
position;
Fig. 4 is a view similar to Fig.2 with a walking
stick/ crutch end tilted as in during use;
Fig. 5 is a perspective view of the spherulitic
insert in material of choice.
(D) Detailed description of the Drawings
The present invention shown in Fig. 2 and. described in detail in Fig. 3 and Fig. 4 is
applied to the base of the walking stick/ crutch as shown in Fig. 1. The shaft/ stick base 2 is disposed onto the end of the walking stick 1 as shown in Fig. 3. The crutch gripping land is an extension of the tubular shaft/ stick 1 of the crutch / walking stick. The base 2 is preferably comprised of an elastomeric material. A clearance 5 is provided between the stick/ shaft 1 and the elastomeric base 2 as shown in Fig. 3, minimizing excessive flexure and fatigue in the

enlarged base at the junction 10 of the vertical neck 3 and the enlarged bottom 4 (as shown in Fig. 4) .
To the bottom of the stick/ shaft 8 is fixed a spherulitic insert 6 (shown in Fig. 5), preferably of a polymeric material, acting as a ball in the ball and socket base 2, as shown in Fig. 2. The said ball and socket mechanism comprises of the spherulitic insert 6 and the crutch base 2, resulting in lesser stress on the vertical neck of the elastomer ic base 3 by restricting the movement of the stick/ shaft.
A circular metal disc 7 is reinforced on the flat bottom 11, located between the bottom surface 12 of the spherulitic insert 6 and the flat bottom 11, preventing the rubbing action between the spherulitic insert 6 and the elastomeric base 2 at the contact surface 11 and resulting in longer life of the enlarged bottom 4 of the elastomeric base 2. The base of the walking stick/ crutch incorporates concentric ridges and grooves 9 facilitating gripping of the ground, resulting in the tread having an appropriate combination of grip and traction.

4 . We Claim:
1. An improved base for walking sticks and crutches comprising of:
a) a base preferably made of an elastomeric material, having a vertical neck and an enlarged bottom, incorporating concentric ridges and grooves at the bottom;
b) a spherulitic insert /(Fig. 5)\ preferably made of a polymeric material, attached to the end of the shaft/ stick;
c) a clearance between the shaft/ stick and the vertical neck of the elastomeric base; and
d) a circular metal disc reinforced on the flat inner bottom surface (^ig- 3)^" -^ ' preventing the rubbing action between the spherulitic insert and the elastomeric base at the contact surface;

7, An improved crutch/ walking stick base, as substantially herein described and as illustrated in the accompanying drawings.