DESC:FIELD OF INVENTION

The present invention relates to a lower-link for tractors. In particular, the present invention relates to a single-piece lower-link construction. More particularly, the present invention relates to a light-weight lower-link of single-piece construction.

BACKGROUND OF THE INVENTION

Normally, a tractor lower link is equipped with a ball joint at either end thereof. The balls are required to have degrees of freedom to facilitate the movement of various implements attached to the tractor and to allow a seamless lifting and lowering of these implements.

This activity calls for the lower link to be 3-piece construction as shown in Figs.1a-1b. This lower-link includes a pair of plated balls, a pair of forged weldons and a central plate for welding the weldons swaged with balls locked therein.

The conventional process involved in making a lower-link of 3-piece construction includes the following process steps:

• Receiving the balls, weldons and the central plate.

• These weldons are manufactured in a forging process.

• Balls are swaged in weldons.

• Weldons swaged with balls are then welded at either end of the central plate to obtain the completed 3-piece lower-link of Fig. 1c.

According to another prior art process, the degree of freedom of the balls is achieved with the construction of locating the balls directly on the lower-link i.e. base plate, instead of on the conventional forged weldons.

The process flow of this prior art lower-link also includes the steps of inserting the ball in the base plate and welding same type of washers on either side of the base plate. However, this construction also leads to serious ball burn-out issues.

Therefore, there is a need for manufacturing low-weight, low-cost lower-links of single-piece construction to avoid the processing costs, e.g. forging and also to avoid the ball burn-outs by completing the welding of the weldons to the central plate before undertaking swaging work for securely locking the balls therein. Such lower-links should also exhibit higher load lifting capacity and higher ball push-out as compared to the two types of prior art lower-links discussed above.

DISADVANTAGES WITH THE PRIOR ART (3-PIECE LOWERLINK)

However, the main disadvantages with the conventional lower-link having a 3-piece construction (Figures 1a-1c) briefly discussed above is the higher manufacturing cost due to use of both forging and swaging processes.

Further, the lower-links a Single-piece construction with identical washers discussed above also have the following disadvantages:

1. Ball plating burn issue, while welding second washer as ball is in contact of washers.

2. Decreased rust-effectiveness by damage to ball plating discussed above.

Therefore, there is an existing need to manufacture a light-weight, low-cost lower-link of single-piece construction, which can eliminate additional forging process. Such lower-link should also have a higher load lifting capacity / ball push-out w.r.t. existing lower-links.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a lower-link which is simple in construction.
Another object of the present invention is to provide a lower-link which is low-weight and thus low-cost to manufacture.

Still another object of the present invention is to provide a lower-link easy to be manufactured by simple processes, by eliminating costly forging process.

Yet another object of the present invention is to provide a lower-link which eliminates ball plating burn-issues.

A still further object of the present invention is to provide a lower-link which is more effective against rust.

A yet further object of the present invention is to provide a lower-link which is useful even for higher HP tractors.

One more object of the present invention is to provide a lower-link which has a higher push-out capacity due to its higher lifting capacity.

An additional object of the present invention is to provide a lower-link which has low-material cost.

Another additional object of the present invention is to provide a lower-link which has better load-capacity in tensile loading.

Still another additional object of the present invention is to provide a lower-link configured according to required load-capacity in different applications.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE PRESENT INVENTION

The single-piece construction of the lower-link configured in accordance with the present invention can also be used for making similar parts having balls to meet the requirement of degrees of freedom thereof.
The innovative sleeve facilitates welding before inserting balls to avoid the first drawback of the prior art, i.e. ball plating burnout and thus helps the ball swaging to avoid the second drawback of the prior art.

The process devised according to the present invention is explained below:

• Welding the first washer with the base plate from below.

• Placing the second washer (sleeve) above the aforesaid assembly and welding it to the base plate.

• Inserting the ball inside the assembly of base plate and first and second washers welded thereto.

• Swaging the second washer (sleeve) to lock the ball in place to avoid any ball plating burn-out.

The above innovative process definitively protects the ball plating and achieves a secured locking of the ball and thus leads to a satisfactory performance during field operations. Therefore, the above process is optimized by swaging from only one side of the base plate, for locking the ball only after welding the first and second washers.

This unique configuration of this lower link comprises:

1. Single-piece construction in contrast to the 3-piece construction of the conventional lower-link.

2. The base plate size is changed, e.g. from earlier 80 x 15 mm to 70 x 10 mm, thereby achieving material saving and thus, a lower manufacturing cost.

3. The second washer is used for ball-locking by one-side swaging only.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the present invention, there is provided a low-weight, low-cost, single-piece lower link assembly for tractors, comprising:

• an elongated base plate with aperture ends thereof slightly bent in opposed directions with respect to the flat face thereof; and

• a respective ball assembly fitted at either end of the base plate;

wherein a respective hole is provided on each end of the base plate for fixing each of the ball assembly therein and wherein the oppositely bent ends of the base plate provide a spring or cushioning effect to the lower link assembly during the loading thereof for reducing the stress induced therein.

Typically, each ball assembly comprises:

(i) a first washer having a profiled inner surface;

(ii) a second washer having a through hole; and

(iii) a respective ball also with a through hole and fixed on the base plate disposed between the first washer and second washer;

wherein the first washer is inserted first into the hole in the base plate from below and fixed therein; and the second washer is subsequently accurately aligned on top of the first washer fixed in the base plate and fixed thereto.

Typically, the ball is a ball having a through hole and flattened boss at either face thereof disposed substantially parallel to the base plate.

Typically, the first washer comprises a spheroidal inner surface corresponding to the outer diameter of the ball for allowing a smooth movement thereof inside the first washer.

Typically, the second washer comprises an internal diameter corresponding to the outer diameter of the ball for allowing a smooth movement thereof inside the second washer;

Typically, the first and second washers are fixed in the base plate by means of a respective welded joint therebetween to support the ball within the cavity produced thereby.

Typically, the ball is placed after welding the first washer and the second washer to the base plate and with the flattened boss thereof disposed substantially parallel to the base plate for securely locking the ball by performing swaging of the top edge of the second washer.

Typically, the weight of the base plate is reduced by about 10 to 15%, preferably by about 12.5% with respect to the base plate of the same size for a conventional 3-piece lower link assembly.

In accordance with another embodiment of the present invention, there is provided a low-weight, low-cost, single-piece lower link assembly for tractors, comprising:

(a) an elongated base plate with aperture ends thereof slightly bent in opposed directions with respect to the flat face thereof; and

(b) a respective ball assembly fixed at either end of the base plate;

(c) the ball assembly having a ball with a through hole, and a flattened boss disposed substantially parallel to the base plate; the ball disposed between a first washer with a spheroidal inner surface corresponding to the outer diameter of the ball and a second washer also having a through hole corresponding to the outer diameter of the ball;

wherein a respective hole is provided on each end of the base plate for fixing each of the ball assembly therein, and wherein the oppositely bent ends of the base plate provide a spring or cushioning effect to the lower link assembly during the loading thereof for reducing the stress induced therein.

Typically, the first and second washers are inserted on either flat face of the base plate, duly aligned accurately to accommodate and allow a smooth movement of the ball inside the partially spheroidal cavity formed by the first and second washers to be subsequently welded on the base plate by means of a respective welded joint therebetween to support the ball within the cavity produced thereby; and wherein the top edge of the second washer being swaged thereafter for securely locking the ball within the ball assembly of the lower link assembly to impart a substantially higher load lifting capacity and higher ball push-out with the lower-weight configuration thereof.

In accordance with the present invention, there is also provided a method for manufacturing a low-weight, low-cost, single-piece lower link assembly for tractors, wherein the method comprises the following method steps:

(A) bending the base plate configured with a profiled aperture, preferably a circular hole made at either end thereof; the bending of ends is in mutually opposed directions, preferably bending away from either faces of the base plate;

(B) making the first lower washer, preferably a circular washer with a bottom collar and a reduced diameter corresponding to the circular hole in the base plate and configured with a spheroidal inner surface corresponding to a predefined diameter;

(C) making the second upper washer, preferably a circular washer with a top profiled stepped collar and a reduced diameter corresponding to the circular hole in the base plate and configured with a through hole corresponding to the predefined diameter;

(D) inserting the reduced diameter portion of the first washer from under the hole in the base plate and performing welding thereof to the lower face of the base plate;

(E) placing the reduced diameter portion of second washer on top of the base plate and welding thereof on the upper face of the base plate;

(F) repeating the steps (A) to (E) at either end of the base plate;

(G) locating the ball of the predefined diameter in a respective partially spheroidal cavity formed between the first and second washers at either end of the based plate;

(H) subsequently swaging the top edge of the second washer; and

whereby each ball is for securely locked within a respective spheroidal cavity of each ball assembly of the lower link assembly, for imparting a substantially higher load lifting capacity and higher ball push-out by virtue of a lower-weight and thus low-cost configuration thereof achieved thereby.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, wherein:

Figure 1a shows an exploded view of the main components of the conventional lower-link for tractors.

Figure 1b shows the conventional construction of the lower-link of Figure 1a.

Figure 1c shows an assembled lower-link of 3-piece construction of Fig. 1b.

Figure 2a shows a completed lower-link assembly configured in accordance with the present invention.

Figure 2b shows the exploded view of the lower-link of Figure 2a.

Figure 3a shows the cross-sectional view of the conventional three-piece lower-link in a first step of the manufacturing process thereof.

Figure 3b shows the cross-sectional view of the first (lower) washer having a spheroidal inner surface for fully supporting the ball.

Figure 3c shows the cross-sectional view of the second (upper) washer having a spheroidal inner surface for fully supporting the ball.

Figure 3d shows the cross-sectional view of the lower link in a second step, in which the first washer is inserted from below the center member of Fig. 3a.

Figure 3e shows the cross-sectional view of the lower link after third step, in which first washer is welded to the center member.

Figure 3f shows the cross-sectional view of the lower link in the fourth step, in which the ball is placed over from above the sub-assembly of Figure 3e.

Figure 3g shows the cross-sectional view of the lower link in the fifth step, in which upper washer is placed over the sub-assembly of Figure 3f.

Figure 3h shows the cross-sectional view of the lower link in the final step, in which the upper washer is welded on central member to finish 3-piece lower-link of Fig.1c.

Figure 4a shows a partial cross-sectional view of the lower-link of single-piece construction in accordance with the present invention in a first step of the manufacturing process thereof.

Figure 4b shows the cross-sectional view of the first (lower) washer having a spheroidal inner surface for fully supporting the ball.

Figure 4c shows the cross-sectional view of the second (upper) washer with inner diameter for accommodating the ball therein.

Figure 4d shows partial cross-sectional view of the lower-link of Figure 4a, in a second step in which the first washer is inserted from below the base plate of Figure 4a.

Figure 4e shows the cross-sectional view of the lower link in a third step, in which a first washer is welded to the base plate from below.

Figure 4f shows the cross-sectional view of the lower link in the fourth step, in which a second washer is placed above the sub-assembly of Figure 4e.

Figure 4g shows the cross-sectional view of the lower link in a fifth step, in which the second washer is welded on top of the base plate.

Figure 4h shows the cross-sectional view of the lower link in the sixth step, in which ball is inserted in the welded sub-assembly of Figure 4g.

Figure 4i shows the cross-sectional view of the lower link in the seventh and final step, in which swaging of the upper second washer is carried out to get the swaged profile.

Figure 5a shows the cross-sectional view of the lower washer of the lower link having an outer diameter and an inner spheroidal surface.

Figure 5b shows the cross-sectional view of the upper washer of the lower link having a sleeve with outer diameter d1 and a through hole/inner diameter.

Figure 5c shows the cross-sectional view of the base plate in a first step, in which the lower washer is inserted from above for subsequent welding.

Figure 5d shows the cross-sectional view of the lower washer is inserted from below and welded to the base plate.

Figure 5e shows the cross-sectional view of the sub-assembly of Figure 5d after placing the upper washer thereon and welding it to the base plate.

Figure 5f shows the cross-sectional view of the sub-assembly of Figure 5d after placing ball in the sub-assembly of Figure 5e.

Figure 5g shows cross-sectional view of the final assembly after swaging the second washer on the base plate sub-assembly of Figure 5f to get the single-piece lower link configured in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the tractor lower-link configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1a shows an exploded view of the main components of the conventional lower-link 100 for tractors. It includes a straight central member 10 and a respective swaged weld-on 20, 30 for locking a ball 40, 50 each at either end of the central member 10.

Figure 1b shows the conventional construction of the lower-link 10 of Figure 1a and produced in a forging operation and balls 40, 50 swaged 44, 54 in the weldons 20, 30 and subsequently welded to central member 10 by means of a respective weld at positions 60, 70.

Figure 1c shows an assembled lower-link 10 of 3-piece construction of Figure 1b with the weldons 20, 30 swaged 44, 54 with balls 40, 50 therein and subsequently welded to the central member 10 (e.g. width W1 usually about 80 mm and thickness 15 mm) by means of a respective weld at positions 60, 70 to make the lower-link 10 rigid.

Figure 2a shows a completed lower-link assembly 100 configured in accordance with the present invention. The width W2 of this lower-link 100 is substantially less than the width W1 of the lower-link shown in Figure 1c (e.g. width W2 is about 70 mm and same thickness of 15 mm). This results in lower weight of the lower-link 100 in comparison with the conventional lower-link 10 (Figure 1c). Moreover, due to slight bend provided at either end of the base plate 110, i.e. at positions 160 and 170, a spring or cushioning effect is produced during the loading of lower-link 100. Therefore, the induced stress is substantially less than any other type of lower-link manufactured until now. This has also been confirmed by generating CAE plots therefor. In comparison to conventional lower-links 10, a reduced vertical section can be used for the same load, thereby lowering material cost, process cost and thus achieving lower cost of lower-link 100.

Figure 2b shows the exploded view of the lower-link 100 of Figure 2a. It includes a base plate 110 and a ball 140, 150 each to be locked at the respective end 120, 130 of the base plate 110 by welding ball locking washers 142, 144 and 152, 154 to avoid disadvantageous ball burn-out of the conventional lower-link 10 which leads to the ball plating damage.

Figure 3a shows the cross-sectional view of the conventional three-piece lower-link 10 in a first step of the manufacturing process thereof, depicting the central member 12 with a through hole at one end 20 or 30 thereof. 60, 70 represents the welded joints of the central member with the weldons.

Figure 3b shows the cross-sectional view of the first (lower) washer 42, 52 having a spheroidal inner surface for fully supporting the ball 40, 50.

Figure 3c shows the cross-sectional view of the second (upper) washer 44, 54 having a spheroidal inner surface for fully supporting the ball 40, 50.

Figure 3d shows the cross-sectional view of the lower link 10 in a second step, in which the first (lower) washer 42, 52 is inserted from below the center member 12 of Figure 3a.

Figure 3e shows the cross-sectional view of the lower link 10 after third step, in which first (lower) washer 42, 52 is welded to the center member 12 by weld 43, 53.

Figure 3f shows the cross-sectional view of the lower link 10 in the fourth step, in which the ball 40, 50 is placed over from above the sub-assembly of Figure 3e for subsequent welding to lock the ball 40, 50 on the central member 12.

Figure 3g shows the cross-sectional view of the lower link 10 in the fifth step, in which upper washer 44, 54 is placed over the sub-assembly of Figure 3f for subsequent welding to lock the ball 40, 50 on the central member 12 of the lower link 10.

Figure 3h shows the cross-sectional view of the lower link 10 in the final step, in which the upper washer 44, 54 is welded on the central member 10 by weld 45, 55, for secure locking of ball 40, 50 to finish the three-piece lower-link 10 depicted in Figure 1c.

Figure 4a shows a partial cross-sectional view of the lower-link 100 of single-piece construction in accordance with the present invention in a first step of the manufacturing process thereof. One of the ends 120, 130 of the base plate 110 is depicted as having a through hole 112 for fully supporting the ball (140, 150) therein. The base plate 110 is slightly bent at positions 160, 170, which helps in higher loading capacity and thus substantially reduces the required cross-section/thickness (70mm x 15mm as against 80mm x 15mm for the conventional lower link 10 of Figures 1a-1c).

Figure 4b shows the cross-sectional view of the first (lower) washer 142, 152 having a spheroidal inner surface for fully supporting the ball 140, 150.

Figure 4c shows the cross-sectional view of the second (upper) washer 144, 154 with inner diameter 141, 151 for accommodating ball 140, 150 therein.

Figure 4d shows partial cross-sectional view of the lower-link 100 of Figure 4a, in a second step in which the first (lower) washer 142, 152 is inserted from below the base plate 110 of Figure 4a.

Figure 4e shows the cross-sectional view of the lower link 100 in a third step, in which a first washer 142, 152 is welded to the base plate 110 from below by a weld 143, 153.

Figure 4f shows the cross-sectional view of the lower link 100 in the fourth step, in which a second washer 144, 154 (with straight inner diameter 141, 151 corresponding to the outer diameter of ball 140, 150 to make a smooth contact therewith) is placed above the sub-assembly of Figure 4e.

Figure 4g shows the cross-sectional view of the lower link 100 in a fifth step, in which the second washer 144, 154 is welded on top of the base plate 110 by weld 145, 155.

Figure 4h shows the cross-sectional view of the lower link 100 in the sixth step, in which ball 140, 150 is inserted within the inner diameter 141, 151 of the upper washer 144, 154 of the welded sub-assembly of Figure 4g.

Figure 4i shows the cross-sectional view of the lower link 100 in the seventh and final step, in which swaging of the top portion of the upper second washer 144, 154 is carried out to obtain the swaged profile 146, 156. This completes a secure locking of the ball 140, 150 in the base plate 110 of lower link 100.

Figure 5a shows the cross-sectional view of the lower washer 142, 152 of the lower link 100 having an outer diameter D1 and an inner spheroidal surface of a diameter slightly higher than the outer diameter of ball 140, 150.

Figure 5b shows the cross-sectional view of the upper washer (144, 154) of the lower link 100 having a sleeve with outer diameter d1 for insertion into the base plate 110 and a through hole/inner diameter d2 slightly higher than the outer diameter of the ball 140, 150. The tapered outer surface of the upper portion of the washer 144, 154 is flattened to configure a thickness t2 to facilitate welding thereof on the base plate 110 (having a through hole of a diameter slightly greater than diameter d1).

Figure 5c shows the cross-sectional view of the base plate 110 in a first step, in which the lower washer 142, 152 is inserted from below and upper washer 144, 154 is inserted from above for subsequent welding.

Figure 5d shows the cross-sectional view of the lower washer 142, 152 inserted from below and welded to the base plate 110.

Figure 5e shows the cross-sectional view of the sub-assembly of Figure 5d after placing the upper washer 144, 154 thereon and welding the same to base plate 110.

Figure 5f shows the cross-sectional view of the sub-assembly of Figure 5d after placing ball 140, 150 in the sub-assembly of Figure 5e.

Figure 5g shows cross-sectional view of the final assembly after swaging the second (top) washer on the base plate sub-assembly of Figure 5f to complete the single-piece lower link 100 configured in accordance with the present invention.

Although, the figures are explained with reference to one side (RHS) of the lower-link, the same process/construction can also be used to the other side (LHS) of lower-link.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The lower-link configured in accordance with the present invention has the following technical and economic advantages:

• Low production cost construction due to its single-piece construction.

• Forging process totally eliminated, thus reducing cost further.

• Low-weight due to reduced width of the base plate, so cost is reduced further.

• Offers higher lifting load and better ball push-out.

• Facilitates in degree of freedom in the ball movement.

• Lower-link is more reliable due to less number of joints.

• Better consistency of part quality due to elimination of manual welding process

In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples. However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept. Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description.

These innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description herein is purely exemplary and for illustration.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

The various features and advantageous details are explained with reference to the non-limiting embodiment/s in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification. ,CLAIMS:We Claim:

1. A low-weight, low-cost, single-piece lower link assembly for tractors, comprising:

• an elongated base plate with aperture ends thereof slightly bent in opposed directions with respect to the flat face thereof; and

• a respective ball assembly fitted at either end of said base plate;

wherein a respective hole is provided on each end of said base plate for fixing each of said ball assembly therein and wherein said oppositely bent ends of said base plate provide a spring or cushioning effect to the lower link assembly during the loading thereof for reducing the stress induced therein.

2. Single-piece lower link assembly as claimed in claim 1, wherein each ball assembly comprises:

(i) a first washer having a profiled inner surface;

(ii) a second washer having a through hole; and

(iii) a respective ball also with a through hole and fixed on said base plate disposed between said first washer and second washer;

wherein said first washer is inserted first into the hole in said base plate from below and fixed therein; and said second washer is subsequently accurately aligned on top of said first washer fixed in said base plate and fixed thereto.

3. Single-piece lower link assembly as claimed in claim 2, wherein said ball is a ball having a through hole and flattened boss at either face thereof disposed substantially parallel to said base plate.

4. Single-piece lower link assembly as claimed in claim 2, wherein said first washer comprises a spheroidal inner surface corresponding to the outer diameter of said ball for allowing a smooth movement thereof inside said first washer.

5. Single-piece lower link assembly as claimed in claim 2, wherein said second washer comprises an internal diameter corresponding to the outer diameter of said ball for allowing a smooth movement thereof inside said second washer.
6. Single-piece lower link assembly as claimed in claim 2, wherein said first and second washers are fixed in said base plate by means of a respective welded joint therebetween to support said ball within the cavity produced thereby.

7. Single-piece lower link assembly as claimed in claim 6, wherein said ball is placed after welding said first washer and said second washer to said base plate and with the flattened boss thereof disposed substantially parallel to said base plate for securely locking said ball by performing swaging of the top edge of said second washer.

8. Single-piece lower link assembly as claimed in claim 1, wherein the weight of said base plate is reduced by about 10 to 15%, preferably by about 12.5% with respect to the base plate of the same size for a conventional 3-piece lower link assembly.

9. A low-weight, low-cost, single-piece lower link assembly for tractors, comprising:

(a) an elongated base plate with aperture ends thereof slightly bent in opposed directions with respect to the flat face thereof; and

(b) a respective ball assembly fixed at either end of said base plate;

(c) said ball assembly having a ball with a through hole, and a flattened boss disposed substantially parallel to said base plate; said ball disposed between a first washer with a spheroidal inner surface corresponding to the outer diameter of said ball and a second washer also having a through hole corresponding to the outer diameter of said ball;

wherein a respective hole is provided on each end of said base plate for fixing each of said ball assembly therein, and wherein said oppositely bent ends of said base plate provide a spring or cushioning effect to the lower link assembly during the loading thereof for reducing the stress induced therein.

10. Single-piece lower link assembly as claimed in claim 9, wherein said first and second washers are inserted on either flat face of said base plate, duly aligned accurately to accommodate and allow a smooth movement of said ball inside the partially spheroidal cavity formed by said first and second washers to be subsequently welded on said base plate by means of a respective welded joint therebetween to support said ball within the cavity produced thereby; and wherein the top edge of said second washer being swaged thereafter for securely locking said ball within said ball assembly of said lower link assembly to impart a substantially higher load lifting capacity and higher ball push-out with the aforesaid lower-weight configuration thereof.

11. A method for manufacturing a low-weight, low-cost, single-piece lower link assembly for tractors as claimed in claim 1 to 10, wherein said method comprises the following method steps:

(A) bending said base plate configured with a profiled aperture, preferably a circular hole made at either end thereof; said bending of ends is in mutually opposed directions, preferably bending away from either faces of said base plate;

(B) making said first lower washer, preferably a circular washer with a bottom collar and a reduced diameter corresponding to said circular hole in said base plate and configured with a spheroidal inner surface corresponding to a predefined diameter;

(C) making said second upper washer, preferably a circular washer with a top profiled stepped collar and a reduced diameter corresponding to said circular hole in said base plate and configured with a through hole corresponding to said predefined diameter;

(D) inserting said reduced diameter portion of said first washer from under said hole in said base plate and performing welding thereof to the lower face of said base plate;

(E) placing said reduced diameter portion of second washer on top of said base plate and welding thereof on the upper face of said base plate;

(F) repeating aforesaid steps (A) to (E) at either end of said base plate;

(G) locating said ball of said predefined diameter in a respective partially spheroidal cavity formed between said first and second washers at either end of said based plate; and

(H) subsequently swaging the top edge of said second washer;

whereby each ball is for securely locked within a respective spheroidal cavity of said each ball assembly of said lower link assembly, for imparting a substantially higher load lifting capacity and higher ball push-out by virtue of a lower-weight and thus low-cost configuration thereof achieved thereby.

Dated: this 31st day of March 2017. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT