Claims:WE CLAIM:
1. A protective cover assembly for a shaft in working implement with increased load bearing capacity, said protective cover assembly, comprising of:
an integrally formed non-circular cover tube [6] with a hollow cross section, having a first end [21] and a second end [22];
a plurality of end plates [23a, 23b], wherein said end plate [23a, 23b] are placed at the said first end [21] and second end [22] of the said non-circular cover tube [6], wherein said end plates [23a, 23b] are provided with a provision for accommodating a plurality of bolts [7];
at least a support frame [25] positioned below the said non-circular hollow tube [6];
a plurality of flat angled plate [8a, 8b] having a top flat end and a bottom end, wherein said bottom end is affixed to the upper side of the said support frame [25],
wherein said top flat end is positioned to receive the said first end [21] of the
non-circular tube with hollow cross section tube [6];
a plurality of flattened U-shaped clamp [9] positioned on the said flat angle plates [8a, 8b];
at least a connector [10a], having a base plate [11a] and a receivable [12a] positioned on the said base plate [11a], wherein said base plate [11a] and said receivable [12a] is provided with a hollow provision for accommodating the drive shaft [2] through the said connector [10a]; and
a plurality of bolts [7], wherein said plurality of bolts [7] fasten the said end plates [23a, 23b] of the non-circular hollow tube [6] with the said connector [10a, 10b],
wherein said flattened U-shaped clamp [9] secures the non-circular tube with hollow cross section [6] to the said top flat end of the flat angled plate [8a, 8b],
wherein said first end plate [23a] of the non-circular tube with hollow cross section [6] is detachably fixed to the said connector [10a] on the gear box side by means
of the said plurality of bolts [7], and
wherein the said second end plate [23b] of the non-circular tube with hollow cross section [6] is detachably fixed to the connector [10b] on the plate end side by means of the said plurality of bolts [7].

2. The protective cover assembly as claimed in claim 1, wherein said non-circular tube with hollow cross section [6] is fixed to the said top flat surface of the flat angled plate [8a, 8b] on the support frame [25] by means of a flattened U-shaped clamp [9] with increased contact surface area thereby increasing the load bearing capacity.

3. The protective cover assembly as claimed in claim 1 or 2, , wherein said non-circular tube of the protective cove assembly includes but not limited to a square tube, rectangular tube, polygonal tube.

4. The protective cover assembly as claimed in claim 1, wherein said hollow cross section is non-circular.

5. The protective cover assembly as claimed in claim 1, wherein the shaft [2] includes but not limited to power take-off shaft, jack shaft, and drive line shaft.

6. The protective cover assembly as claimed in claim 1, wherein the working implement is a rotary tiller. , Description:FIELD OF INVENTION
The present invention relates to an agricultural working implement. More particularly, the present invention relates to a protective cover assembly for shaft of the agricultural working implement, which increases the load bearing capacity and durability of the cover. Further, the present invention relates to a protective cover assembly, which reduces the stress induced on the cover during fastening thereby reducing the failure rate and prolonging the duty cycle of the protective cover used to protect the shaft.

BACKGROUND OF INVENTION

Farmland tillage is one of the most basic and important aspect of agricultural production. Rotary tiller is a secondary tillage equipment for soil preparation. The rotary tiller is equipped with tractors is used to perform harrowing, mulching, pulverization and leveling in one single operation. Because of its strong ability to break the soil and flatten the surface after ploughing, it has been widely used. Rotary tillage after breaking the soil, it can effectively cut the roots of crops and bury them. The soil surface is loosen and flattened after ploughing for easy seeding operations. Rotary tillers generally include a series of tines which are mounted on a single horizontal tiller shaft and rotated in order to provide a slicing action in which the tines cut through the soil. The rotary tillers provide power and rotation to the tiller shaft through a worm drive or a chain drive system. In the drive train layout, a drive shaft technically called as jackshaft is used to transfer drive from the gearbox to the tiller shaft through the side drop down gears without interfering with the tines as they rotate. During such operation several problems relating to the shaft can occur such as, vegetation commonly wraps around the small tine shaft very tightly and the portion of the motor drive shaft that is exposed to the vegetation also gets affected.

Although the rotary tillers have undergone a variety of style changes, it is majorly inseparable from the rotation of the drive shaft. The main execution part of the rotary tiller is the drive shaft which requires adequate protection to avoid damage due to external factors. Traditionally skeleton oil seal is used to block the water and foreign matter from affecting these shafts. However the skeleton oil seal is easily damaged by the hard object. The bearing joints are vulnerable to the entry of mud and soil, leading to early wear of the bearing. Further results in the corrosion and rusting of the shaft head, which causes the failure in the operation of the rotary tillage machinery.

In the related art, protective covers encasing the shaft is used for protecting the shaft as well as improving the working conditions of the rotary tiller machinery. However, the existing protecting covers are too simple in structure and has poor load bearing capacity.

Referring to Figures 1, 1a and 2, conventionally, the protective cover [1] with a circular cross section is being used to protect the jackshaft [2] to avoid damage due to external factors. The circular protective cover [1] is welded by means of the flange [3] to the gear box side and plate end side respectively as shown in Figure 2. Further the circular protective cover [1] is positioned on the flat angled plate [4] with U-shaped clamp [5] as shown in Figure 1a, which produces a line contact thereby enhancing the stress induced on the circular cover [1] during fastening. Additionally the said circular protective cover [1] rests on the profile machined circular support which adds additional cost and assembly constraints to the rotary tiller machinery.

JPH0658343 discloses a driving shaft provided with inside and outside non- circular tubes which are removably-fitted so as not to rotate relatively and so as to slide freely in an axial direction within a prescribed stroke region to each other, and universal joints which are mounted respectively at both the edges of the non-circular tube assembly bodies. However, the driving shaft is provided with inner and outer non- circular tube and they will slide free in axial direction.

Japanese patent document JP10203187 provides a safety cover for a drive shaft to prevent the generation of vibration and noise even when a drive shaft is rotated at a high speed. A safety cover for a drive shaft is formed with a pair of inner and outer cover members that are provided to be slidably and rotatably coupled to the respective yokes through respective slide rings and slidably fitted in each other. The section of the inner cover member forms a circular section, the section of the outer cover member forms a polygonal section, and the diameter of the circular section of the inner cover member is slightly larger than the diameter of inscribing circle of the polygonal section.

NL1012964 relates to a shaft between a driving and a driven implement, provided with a safety cover. wherein the said safety cover includes a tube of suitable material which is mounted on the shaft by means of a bearing ring arranged at each end, and are provided with releasabe coupling elements. The coupling shaft consists of a non-round inner tube and a non-round outer tube fitting therearound. The two parts are mutually slidable in lengthwise direction so that coupling shaft is telescopic and can have different lengths.

All of the above cited prior-art and state of the art technologies deals with protective cover, sealing or casing for the drive shaft of an agricultural working machine. But none of the technology addresses the problem of reduced load bearing capacity of the protective cover and its associated stress, durability and assembly constraints of such protective cover for jackshaft. Accordingly, there exists a need for a protective cover assembly to protect the drive shaft/ jackshaft in a working machine, which increases the load bearing capacity and durability of the cover. Further, there exists a need for an improved assembly structure which reduces the enhanced stress experienced by the conventional protective covers thereby increasing the durability and prolonging the duty cycle of the protective covers used to protect the drive shaft/jack shaft on the working machine.

OBJECTS OF INVENTION
One or more problems of the conventional prior art may be overcome by various embodiment of the present invention.

It is the primary object of the present invention to provide a protective cover assembly with increased load bearing capacity and durability, to protect the shaft in a working implement.
It is another object of the present invention to provide a protective cover assembly with a non-circular cross section to protect the shaft in a working implement, which reduces the stress induced on the cover during fastening.

It is still another object of the present invention to provide a protective cover assembly with a non-circular cross section with a higher section modulus.

It is yet another object of the present invention to provide a protective cover assembly with a non-circular cross section which is fixed and rests on a flat angled plate with increased surface area of contact.

It is another object of the present invention to provide a protective cover assembly for protecting the shaft of the working implement with reduced failure rate and prolonged duty cycle.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the invention there is provided a protective cover assembly with increased load bearing capacity for a shaft in working implement, said protective cover assembly, comprising of:
an integrally formed non-circular cover tube with a hollow cross section, having a first end
and a second end;
a plurality of end plates, wherein said end plate are placed at the said first end and second end of the said non-circular cover tube, wherein said end plates are provided with a provision for accommodating a plurality of bolts;
at least a support frame positioned below the said non-circular hollow tube;
a plurality of flat angled plate having a top flat end and a bottom end, wherein said bottom end is affixed to the upper side of the said support frame, wherein said top flat end is positioned to receive the said first end of the non-circular hollow cross section tube;
a plurality of flattened U-shaped clamp positioned on the said flat angle plates;
at least a connector, having a base plate and a receivable positioned on the said base plate, wherein said base plate and said receivable is provided with a hollow provision for accommodating the drive shaft through the said connector; and
a plurality of bolts, wherein said plurality of bolts fasten the said end plates of the
non-circular hollow tube with the said connector,
wherein said flattened U-shaped clamp secures the non-circular hollow cross section tube to the said top flat end of the flat angled plate,
wherein said first end plate of the non-circular hollow tube is detachably fixed to the said connector on the gear box side by means of the said plurality of bolts, and
wherein the said second end plate of the non-circular hollow tube is detachably fixed to the connector on the plate end side by means of the said plurality of bolts.

It is another aspect of the present invention, wherein the non-circular hollow cross section cover is fixed on the support frame with flat angle plate having surface area of contact which increases the load bearing capacity of the cover, thereby increasing the durability of the cover.

It is another aspect of the present invention, wherein the flat angled plate is in the shape of L-angle.

It is another aspect of the present invention, wherein the non-circular tube with hollow cross section includes but not limited to square tube, rectangular tube, polygonal tube.

It is another aspect of the present invention, wherein the shaft includes but not limited to power take-off shaft, jack shaft, and drive line shaft.

It is another aspect of the present invention, wherein the working machine is a rotary tiller.

BRIEF DESCRIPTION OF DRAWINGS
Figure 1 illustrates the working implement with circular cross section protective cover assembly for the shaft according to the prior art.
Figure 1a illustrates the enlarged view of the fastening of the circular cross section protective cover assembly to the gearbox side of the working implement by means of U-bolt according to the prior art.
Figure 2 illustrates the cross sectional view of the working implement with circular cross section protective cover assembly for the drive shaft with welded flange connection structure according to the prior art.
Figure 3 illustrates a working implement with a non-circular cross section protective cover assembly for the drive shaft according to the present invention.
Figure 4: illustrates the enlarged view of the fastening of the non-circular cross section protective cover assembly to the gearbox side of the working implement by means of flattened U-bolt according to the present invention.
Figure 5: illustrates the cross sectional view of the working implement with a non-circular cross section protective cover assembly for the shaft with bolted assembly connection structure according to the present invention.
Figure 6: illustrates the connector in the gear box side of the working implement with non-circular cross section protective cover assembly for the shaft according to the present invention.
Figure 7: illustrates the connector in the plate side of the working implement with non-circular cross section protective cover assembly for the shaft according to the present invention.
Figure 8: illustrates the enlarged view of the gear box side of the working implement with circular cross section protective cover assembly for the shaft according to the prior art.
Figure 9: illustrates the enlarged view of the gear box side of the working implement with non-circular cross section protective cover assembly for the shaft according to the present invention.
Figure 10: illustrates the graph representing round tube construction according to the prior art.
Figure 11: illustrates the graph representing stress curve for round tube construction according to the prior art.
Figure 12: illustrates the graph representing square tube construction according to the present invention.
Figure 13: illustrates the graph representing stress curve for square tube construction according to the present invention.

DETAILED DESCRIPTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
The present invention as embodied by an “Protective cover assembly for agricultural working implement shaft" succinctly fulfils the above-mentioned need(s) in the art. The present invention has objective(s) arising as a result of the above-mentioned need(s), said objective(s) being enumerated below. In as much as the objective(s) of the present invention are enumerated, it will be obvious to a person skilled in the art that, the enumerated objective(s) are not exhaustive of the present invention in its entirety, and are enclosed solely for the purpose of illustration. Further, the present invention encloses within its scope and purview, any structural alternative(s) and/or any functional equivalent(s) even though, such structural alternative(s) and/or any functional equivalent(s) are not mentioned explicitly herein or elsewhere, in the present disclosure. The present invention therefore encompasses also, any improvisation(s)/modification(s) applied to the structural alternative(s)/functional alternative(s) within its scope and purview. The present invention may be embodied in other specific form(s) without departing from the spirit or essential attributes thereof.

Throughout this specification, the use of the word "comprise" and variations such as "comprises" and "comprising" may imply the inclusion of an element or elements not specifically recited.

The present invention is thus directed to a protective cover for a shaft. More particularly, the present invention relates to a protective cover assembly, which increases the load bearing capacity and durability of the cover.
Referring to Figures 3 to 7, the present invention provides a protective cover assembly for a shaft in working implement, said protective cover assembly, comprising of: an integrally formed non-circular cover tube [6] with a hollow cross section, having a first end [21] and a second end [22]; a plurality of end plates [23a, 23b], wherein said end plate [23a, 23b] are placed at the said first end [21] and second end [22] of the said non-circular cover tube [6], wherein said end plates [23a, 23b] are provided with a provision for accommodating a plurality of bolts [7]; at least a support frame [25] positioned below the said non-circular hollow tube [6]; a plurality of flat angled plate [8a, 8b] having a top flat end and a bottom end, wherein said bottom end is affixed to the upper side of the said support frame [25], wherein said top flat end is positioned to receive the said first end of the non-circular hollow cross section tube [6]; a plurality of flattened U-shaped clamp [9] positioned on the said flat angle plates [8a, 8b], wherein said flattened U-shaped clamp [9] secures the non-circular hollow cross section tube [6] to the said top flat end of the flat angled plate [8a, 8b], which increases the load bearing capacity of said non-circular
hollow cross section cover [6]; at least a connector [10a, 10b], having a base plate [11a, 11b] and a receivable [12a, 12b] positioned on the said base plate [11a, 11b], wherein said base plate [11a, 11b] and said receivable [12a, 12b] is provided with a hollow provision for accommodating the drive shaft [2] through the said connector [10a, 10b]; and a plurality of bolts [7], wherein said plurality of bolts [7] fasten the said end plates [23a, 23b] of the non-circular hollow tube [6] with the said connector [10a, 10b], wherein said first end plate [23a] of the non-circular hollow tube [6] is detachably fixed to the said connector [10a] on the gear box side by means of the said plurality of bolts [7] as shown in Figures 5 and 6, wherein the said second end plate [23b] of the non-circular hollow tube [6] is detachably fixed to the connector [10b] on the plate end side by means of the said plurality of bolts [7] as shown in Figures 5 and 7.

In the preferred embodiment of the present invention, wherein said non-circular tube of the protective cove assembly includes but not limited to a square tube, rectangular tube, polygonal tube.

In the preferred embodiment of the present invention, wherein said shaft [2] includes but not limited to power take-off shaft, jack shaft, and drive line shaft.

In the preferred embodiment of the present invention, wherein said working implement includes agricultural equipments including tractor, rotary tiller, harvester, combines, etc.

As shown in fig 8. in the case of conventional shaft protection cover with a circular cross section, the said protective cover [1] is fastened to the flat angled plate [4] by means of a U-shaped clamp [5]. This result in a line contact between the protective cover [1] and contact surface of the flat angled plate [4]. This line contact induces more stress on the protective cover [1] during fastening and also during resting. This results in the reduced life-cycle of the protective cover [1]. In another feature, the said protective cover with circular cross section rests on the profile machined circular support which adds additional cost and assembly constraints. As shown in Fig.9 the protective cover assembly with non-circular tube hollow cross section [6] is fixed to the said top flat surface of the flat angled plate [8a, 8b] on the support frame [25] by means of a flattened U-shaped clamp [9]. This eliminates the line contact between the non-circular protective cover [6] and the flat plate [8a, 8b] and provides an increased contact surface area between the same. The increased contact surface area between the protective cover assembly with non-circular tube hollow cross section [6] and the flat angled plate [8a, 8b] increases the load bearing capacity of said non-circular protective cover [6].

In the preferred embodiment of the present invention, said protective cover with non-circular tube hollow cross section [6] is provided with a higher section modulus. The said protective cover with non-circular tube hollow cross section [6] is fixed on the flat angle plate [8a, 8b] supported on the said support frame [25], wherein said flat angle plate [8a, 8b] is in the shape of L-angle as shown in Figure 4 which provides an increase contact surface area, which increases the load bearing capacity of the cover [6], thereby increasing its durability. Thus the protective cover assembly having non-circular tube with hollow cross section according to the present invention reduces the failure rate and prolonging the duty cycle of the protective cover used to protect the shaft in the working implement.

EXAMPLES

For illustration, the protective cover assembly with circular hollow cross section [1] according to the prior art having dimensions of 70 x 3 mm for shaft [2] as shown in Figure 1 in the rotary tiller when subject to torque of 100 Nm and 60 Nm at different sections results the stress measured as illustrated in Table-1.
TABLE- 1:
Protective cover assembly with circular hollow cross section
Torque- 100Nm K=0.2 Torque- 60Nm K=0.13
Circular cross section- 70x3 mm Circular cross section - 70x3 mm
Section Stress (N/mm2) FOS Section Stress N/mm2 FOS
1.01 1.69
1 31.69 1 19.01
2 38.11 2 22.87
3 35.38 3 21.23
4 42.89 4 25.74
5 50.11 5 30.06
6 59.66 6 35.80
7 137.78 7 82.67
8 264.94 8 158.97
9 305.71 9 183.42

Referring to Figure 10, combined bending moment diagram of fixed end moment and simply supported beam with vertical loads of the protective cover assembly with circular hollow cross section [1] according to the prior art. As the loads are not acting symmetrically, bending moment at Point A (Ma) with and bending moment at Point B (Mb) will be different. In this case, Ma will be more than Mb as the load is nearer to Point B. (Ma=5343.06 Knmm and Mb=1117.795 Knmm). The Bending Moments due to end moments will be trapezium as shown. The bending moments for a simply supported beam carrying an eccentric load will be triangle with max bending moment @ point load at C.
Referring to Figure 11, stress is calculated for different sections from flange end as shown since to failure occurs at area nearer to mating of the protective cover assembly with circular hollow cross section [1] according to the prior art with Flanges. Stress curve is plotted for the protective cover assembly with circular hollow cross section [1] as shown in Figure 11 where section modulus is 10138.81 mm3 and Factor of Safety (FOS) when subjected to 100 Nm and 60 Nm is 1.01 and 1.69 as shown in Table 1. Stress induced is 305.71 Mpa due to the protective cover assembly with circular hollow cross section [1] will attain the yield point and leads to early failure of protective cover tube.

The protective cover assembly with square hollow cross section [6] according to the present invention having dimensions of 63.5 x 5 mm for shaft [2] in the rotary tiller as shown in Figure 3 when subject to torque of 100 Nm and 60 Nm at different sections results the stress measured as illustrated in Table-2.
TABLE- 2
Protective cover assembly with square hollow cross section
Torque- 100Nm K=0.2 Torque- 60Nm K=0.13
Square cross section cover 63.5x5mm Square cross section cover 63.5x5mm
Section Stress (N/mm2) FOS Section Stress N/mm2 FOS
2.12 2.29
1 21.15 1 19.52
2 22.47 2 20.74
3 28.15 3 25.99
4 29.72 4 27.43
5 31.28 5 28.88
6 32.85 6 30.32
7 34.41 7 31.76
8 67.21 8 62.04
9 146.48 9 135.21

When comparing to the stress induced of the protective cover assembly with circular hollow cross section [1] according to the prior art and the protective cover assembly with square hollow cross section [6] according to the present invention as illustrated in Table-1 and Table- 2, the values of the stress induced with square hollow cross section [6] according to the present invention is low.

Referring to Figure 12, combined bending moments of fixed end moment and simply supported beam with vertical loads of the protective cover assembly with square hollow cross section [6] according to the present invention. In this case, bending moment at Point A (Ma) will be more than bending moment at Point B (Mb) as the load is nearer to Point B. (Ma=5343.06 Knmm and Mb=1117.795 Knmm). The bending moments due to end moments will be trapezium as shown in Figure 12. The bending moments for a simply supported beam carrying an eccentric load will be triangle with max bending moment @ point load at C.

Referring to Figure 13, stress is calculated and plotted for different sections from flange end of the protective cover assembly with square hollow cross section [6] according to the present invention. Stress curve is plotted for the protective cover assembly with square hollow cross section [6] is shown in Figure 12 whereas Section modulus is 21172.09 mm3 and FOS when subjected to 100 Nm and 60 Nm is 2.12 and 2.29 as shown in Table 2, This results the protective cover assembly with square hollow cross section [6] according to the present invention having increased FOS when compared to protective cover assembly with circular hollow cross section [1] according to the prior art and not having steep increase in stress value thus increasing the load bearing capacity of protective cover tube.

It will be apparent to the person skilled in the art that the above description is for illustrative purposes only should not be considered as limiting. Various modifications, additions, alterations, and improvements without deviating from the scope of the invention may be made by a person skilled in the art.