Claims:We claim:

1. A device (150) for determining the load carrying capability of the thrust bearing (110) in a crankshaft (120) of an internal combustion engine, said device comprises:

• an extension shaft (140) fitted on one end of said crankshaft (120);

• a taper roller bearing (126, 128) fitted on said extension shaft (140);

• an extension rod (142) mounted on said taper roller bearing (126, 128);

• a load-cell (144) mounted on the first end of extension rod (142);

• a plate assembly (130) fitted at the second end of extension rod (142);

• a loading-nut (136) placed on said second end of extension rod (142);

• a thermocouple (146) in contact with a pair of thrust washers (124) placed on either side of said thrust bearing (110) disposed between the internal faces of collars (122) of said crankshaft (120); and

• a data logger (148) connected to said thermocouple (146) at one end thereof and connected to said load-cell (140) at the other end thereof.

2. Device as claimed in claim 1, wherein said taper roller bearing (126, 128) comprises an inner race fixed on said extension shaft (140) and an outer race (126) covered by the first end of an outer bearing cap (128).

3. Device as claimed in claim 2, wherein the first end of said extension rod (142) is centrally mounted on the second end of said outer race (126).

4. Device as claimed in claim 1, wherein said load-cell (144) is mounted adjacent the first end of extension rod (142) and between said outer race (128) and said plate assembly (130).
5. Device as claimed in claim 1 or 4, wherein said plate assembly comprises:

• a fixed plate (132) mounted on the front cover of said internal combustion engine and said extension rod (142) centrally passing therethrough;

• a moveable plate (134) disposed parallel to and at a distance from said fixed plate (132), the second end of said extension rod (142) passing centrally therethrough;

• a plurality of compression springs (138) disposed between said fixed plate (132) and said moveable plate (134); and

• said loading-nut (136) tightened on said second of said extension rod (142);

wherein said second end of said extension rod (142) comprises screw threads for tightening thereon said loading-nut (136) having corresponding internal threads in order to compress said springs (138) of plate assembly (130) to exert a gradual thrust load on said thrust bearing (110).

6. Device as claimed in claim 5, wherein said thrust load is applied by tightening said loading-nut (136) on said plate assembly (130) and sequentially transmitted to said thrust bearing (110) via said extension rod (142), load-cell (144), taper roller bearing (126, 128), extension shaft (140) and through collars (122) of crankshaft (120).

7. Device as claimed in claim 6, wherein said thrust load is applied in steps tightening said loading-nut (136) on said plate assembly (130) to move said moveable plate (134) towards said fixed plate (132) and the temperature of said thrust washers (124) is allowed to stabilize before proceeding to next step of thrust loading.

8. Device as claimed in claim 7, wherein at each step of said thrust loading, said load-cell (144) captures the thrust load applied on said thrust bearing (110) and simultaneously said thermocouple (146) captures the corresponding temperature of said thrust washers (124) and said temperature and said thrust load values are used by said data logger (148) for determining the load carrying capability of said thrust bearing (110)

9. Device as claimed in claim 8, wherein said data logger (148) is configured to monitor and capture every increase in the temperature of said thrust washers (124) and any sudden exponential increase in temperature of said thrust washers (124) by means of said thermocouple (146) corresponds to the applied thrust load which is indicated as the thrust bearing failure load (TBFL).

10. A device (150) for determining the load carrying capability of the thrust bearing (110) in a crankshaft (120) of an internal combustion engine, said device (150) comprises:

• an extension shaft (140) fitted on one end of said crankshaft (120);

• a taper roller bearing (126) having an inner race and an outer race and an outer bearing cap (128) covering taper roller bearing (126); said inner race mounted on the outer diameter of extension shaft (140);

• an extension rod (142) with the first end thereof centrally mounted on the face of outer bearing cap (128) disposed away from extension shaft (140) and the other end of extension rod (142) having screw threads;

• a plate assembly (130) mounted at said screw-threaded end of extension rod (142);

• said plate assembly (130) having a fixed plate (132) mounted on the front cover of said internal combustion engine, a moveable plate (134) disposed parallel to and spaced from fixed plate (132) and extension rod (142) centrally passing through fixed and moveable plates (132, 134), and a plurality of compression springs (138) disposed between fixed and moveable plates (132, 134);

• a loading nut (136) screwed on said second threaded end of extension rod (142) for moving moveable plate (134) towards fixed plate (132) to compress said springs (138) for step-wise application of incremental thrust loads on said thrust bearing (110);

• a load-cell (144) disposed near said first end of extension rod (140) and mounted between outer bearing cap (128) and fixed plate (132);

• a thermocouple (146) contacting said thrust washers (124) placed on either side of thrust bearing (110) disposed between collars (124) of said crankshaft (120);

wherein a data logger (148) is connected to thermocouple (146) at one end thereof for continuously monitoring, capturing and displaying the change in the temperature of said thrust washers (124), and the other end of data logger (148) is connected to load-cell (144) for capturing the corresponding thrust load applied on said thrust bearing (110) at each step of thrust loading and sequentially transmitted via said extension rod (142), load-cell (144), taper roller bearing (126, 128), extension shaft (140) and through collars (122) of crankshaft (120) to said thrust bearing (110); said data logger also configured to capture other engine parameters besides temperature of thrust washers (124) and load transmitted through load-cell (144).

11. A method for determining the load carrying capability of the thrust bearing (110) in a crankshaft (120) of an internal combustion engine by means of a device (150) as claimed in claim 1 or 10, wherein said method comprises the steps of:

• Loading the engine loaded on the testbed and coupled to a dynamometer similar to a regular reliability test;
• assembling fixed plate (132) of said device (150) on the front cover of said engine;

• connecting said thrust washers (124) of said thrust bearing (110) to said thermocouple (146);

• connecting said load cell (144) to said data logger (148) for capturing step-wise thrust load increments and corresponding rise in temperature of thrust washers (124) and configuring said data thrust load and temperature data along with other engine parameters;

• warming-up said engine and slowly loading said thrust bearing (110) with the help of the displayed value of said load cell (144);

• observing the gradual temperature rise in thrust washers (124) with said thrust bearing loading;

• increasing the thrust load step-by-step and waiting for a few minutes after applying thrust load at each step until achieving a stabilized thrust washer temperature therefor;

• recording the thrust bearing failure point as the Thrust Bearing Failure Load (TBFL) at which an exponential increase is observed in the temperature of thrust washers (124); and

• calculating the ratio of maximum thrust load applied before reaching said thrust bearing failure point to determine the Thrust Bearing Load Carrying Capability (TBLCC) of said thrust bearing (110).

Dated this 23rd day of August 2019.

Digitally Signed.

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043. , Description:FIELD OF INVENTION

The present invention concerns a device for testing the load carrying capability of thrust bearings for internal combustion engines. In particular, the present invention relates to a device for validating the load carrying capability of thrust bearings for internal combustion engines. More particularly, the present invention relates to a device to establish Factor of Safety (FOS) for the designed load of thrust bearings for internal combustion engines.

BACKGROUND OF THE INVENTION

A thrust bearing is a particular type of rotary bearing, which permits rotation between parts, however, is designed to support a predominantly axial load. A thrust bearing can be e.g. a thrust ball bearing or cylindrical roller thrust bearing or tapered roller thrust bearing or even a spherical roller thrust bearing. Tapered roller thrust bearing are the most commonly used in automotive applications e.g. for supporting automobile wheels and are used in pairs to accommodate axial thrust in either direction as well as to bear radial loads. Tapered roller thrust bearing can support greater thrust loads than thrust ball bearing due to larger contact area, but at substantially higher manufacturing costs.

PRIOR ART

In internal combustion engines, the arrangement of flywheel and crankshaft involves thrust washer placed between the crankshaft collars (Fig. 1a). This thrust washer transfers the load produced due to clutch operation to the engine.

Therefore, it is necessary that the load carrying capability of the thrust bearings and to establish the design load therefor by observing the thrust washer temperature and by considering the required Factor of Safety (FOS).
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 device for testing the load carrying capability of thrust bearings in internal combustion engines.

Another object of the present invention is to provide a device for validating the load carrying capability of thrust bearings in internal combustion engines

Still another object of the present invention is to establish the Factor of Safety (FOS) for the design load of thrust bearings in internal combustion engines

Yet another object of the present invention is to provide a device for testing the load carrying capability of thrust bearings in internal combustion engines in actual working environment.

A further object of the present invention is to provide a simple device for testing the load carrying capability of thrust bearings in internal combustion engines

A still further object of the present invention is to provide a low-cost device using simple method for testing load carrying capability of ICE thrust bearings.

A yet further object of the present invention is to provide a low-cost device using inexpensive method for testing load carrying capability of ICE thrust bearings.

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.
SUMMARY OF INVENTION

In accordance with a first embodiment of the present invention, there is provided a device for determining the load carrying capability of the thrust bearing in a crankshaft of an internal combustion engine, the device comprises:

• an extension shaft fitted on one end of the crankshaft;

• a taper roller bearing fitted on the extension shaft;

• an extension rod mounted on the taper roller bearing;

• a load-cell mounted on the first end of extension rod;

• a plate assembly fitted at the second end of extension rod;

• a loading-nut placed on the second end of extension rod;

• a thermocouple in contact with a pair of thrust washers placed on either side of the thrust bearing disposed between the internal faces of collars of the crankshaft; and

• a data logger connected to the thermocouple at one end thereof and connected to the load-cell at the other end thereof.

Typically, the taper roller bearing comprises an inner race fixed on the extension shaft and an outer race covered by the first end of an outer bearing cap.

Typically, the first end of the extension rod is centrally mounted on the second end of the outer race.

Typically, the load-cell is mounted adjacent the first end of extension rod and between the outer race and the plate assembly.

Typically, the plate assembly comprises:

• a fixed plate mounted on the front cover of the internal combustion engine and the extension rod centrally passing therethrough;

• a moveable plate disposed parallel to and at a distance from the fixed plate, the second end of the extension rod passing centrally therethrough;

• a plurality of compression springs disposed between the fixed plate and the moveable plate; and

• the loading-nut tightened on the second of the extension rod;

wherein the second end of the extension rod comprises screw threads for tightening thereon the loading-nut having corresponding internal threads in order to compress the springs of plate assembly to exert a gradual thrust load on the thrust bearing.

Typically, the thrust load is applied by tightening the loading-nut on the plate assembly and sequentially transmitted to the thrust bearing via the extension rod, load-cell, taper roller bearing, extension shaft and through collars of crankshaft.

Typically, the thrust load is applied in steps tightening the loading-nut on the plate assembly to move the moveable plate towards the fixed plate and the temperature of the thrust washers is allowed to stabilize before proceeding to next step of thrust loading.

Typically, at each step of the thrust loading, the load-cell captures the thrust load applied on the thrust bearing and simultaneously the thermocouple captures the corresponding temperature of the thrust washers and the temperature and the thrust load values are used by the data logger for determining the load carrying capability of the thrust bearing.

Typically, the data logger is configured to monitor and capture every increase in the temperature of the thrust washers and any sudden exponential increase in temperature of the thrust washers by means of the thermocouple corresponds to the applied thrust load which is indicated as the thrust bearing failure load (TBFL).

In accordance with a second embodiment of the present invention, there is provided a device for determining the load carrying capability of the thrust bearing in a crankshaft of an internal combustion engine, the device comprises:

• an extension shaft fitted on one end of the crankshaft;

• a taper roller bearing having an inner race and an outer race and an outer bearing cap covering taper roller bearing; the inner race mounted on the outer diameter of extension shaft;

• an extension rod with the first end thereof centrally mounted on the face of outer bearing cap disposed away from extension shaft and the other end of extension rod having screw threads;

• a plate assembly mounted at the screw-threaded end of extension rod;

• the plate assembly having a fixed plate mounted on the front cover of the internal combustion engine, a moveable plate disposed parallel to and spaced from fixed plate and extension rod centrally passing through fixed and moveable plates, and a plurality of compression springs disposed between fixed and moveable plates;

• a loading nut screwed on the second threaded end of extension rod for moving moveable plate towards fixed plate to compress the springs for step-wise application of incremental thrust loads on the thrust bearing;

• a load-cell disposed near the first end of extension rod and mounted between outer bearing cap and fixed plate;

• a thermocouple contacting the thrust washers placed on either side of thrust bearing disposed between collars of the crankshaft;

wherein a data logger is connected to thermocouple at one end thereof for continuously monitoring, capturing and displaying the change in the temperature of the thrust washers, and the other end of data logger is connected to load-cell for capturing the corresponding thrust load applied on the thrust bearing at each step of thrust loading and sequentially transmitted via the extension rod, load-cell, taper roller bearing, extension shaft and through collars of crankshaft to the thrust bearing; the data logger also configured to capture other engine parameters besides temperature of thrust washers and load transmitted through load-cell.

In accordance with the present invention, there is also provided a method for determining the load carrying capability of the thrust bearing in a crankshaft of an internal combustion engine by means of the aforesaid device, wherein the method comprises the steps of:

• Loading the engine loaded on the testbed and coupled to a dynamometer similar to a regular reliability test;

• assembling fixed plate of the device on the front cover of the engine;

• connecting the thrust washers of the thrust bearing to the thermocouple;

• connecting the load cell to the data logger for capturing step-wise thrust load increments and corresponding rise in temperature of thrust washers and configuring the data thrust load and temperature data along with other engine parameters;

• warming-up the engine and slowly loading the thrust bearing with the help of the displayed value of the load cell;

• observing the gradual temperature rise in thrust washers with the thrust bearing loading;
• increasing the thrust load step-by-step and waiting for a few minutes after applying thrust load at each step until achieving a stabilized thrust washer temperature therefor;

• recording the thrust bearing failure point as the Thrust Bearing Failure Load (TBFL) at which an exponential increase is observed in the temperature of thrust washers; and

• calculating the ratio of maximum thrust load applied before reaching the thrust bearing failure point to determine the Thrust Bearing Load Carrying Capability (TBLCC) of the thrust bearing.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.

Figure 1 shows a conventional arrangement of the flywheel and crankshaft in an internal combustion engine used for clutch operation therein.

Figure 2 shows an enlarged view of typical thrust washers placed between the crankshaft collars used for testing the load capability of the thrust bearings.

Figure 3 shows the conventional arrangement of thrust washers placed between the crankshaft collars and used for testing the load capability of the thrust bearings on a testing rig at the supplier’s end.

Figure 4 shows a schematic arrangement for checking the thrust washer temperature for testing the load carrying capability of thrust bearings on the engine itself by the device configured in accordance with the present invention and thus conducted in an actual application environment.

Figure 5 shows perspective view of the arrangement for measuring the load carrying capability of thrust bearings according to the present invention.

Figure 6 shows a side cross-sectional view of the arrangement of Figure 5.

Figure 7 shows a graphical representation of checking the thrust washer temperature and friction torque for testing the load carrying capability of thrust bearings according to the present invention. The graphs are drawn with thrust load (kg) on x-axis and friction torque (kg-m) and thrust washer temperature on y-axis respectively.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the device for measuring the load carrying capability of thrust bearings 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.

Here, a reference is made to the accompanying drawings, which form part of this specification and in which specific exemplary embodiments are shown for illustration, in which the invention can be exercised.

In this respect, the directional terminology such as “above”, “below/under”, “in front”, “behind”, “forward”, “rearward”, etc. are used with reference to the orientation of the described figure(s). Since components of exemplary embodiments can be positioned in a number of different orientations, the directional terminology is used only for illustration and is not limiting in any way.

It should be noted that other embodiments can be used, and structural or logical modifications can be undertaken without departing from the scope of protection of the present invention.
It should be noted that the features of the different exemplary embodiments described herein can be combined with each other, unless not specifically stated otherwise.

Therefore, the following detailed description is not to be understood in a restrictive sense, and the scope of protection of the present invention is defined by the accompanying claims.

Within the scope of this description, the terms "joined", "connected" and "coupled" are used for describing a direct as well as an indirect joint, a direct or indirect connection and a direct or indirect coupling. In the figures, identical or similar elements are provided with identical reference numerals, where appropriate.

Figure 1 shows a conventional arrangement of the flywheel and crankshaft in an internal combustion engine used for clutch operation therein. The clutch load Lc is applied on clutch 40, which is transferred to the thrust washers 12 disposed on either side of the thrust bearing 10 and fitted between the collars of the crankshaft 20 via flywheel 30.

Figure 2 shows an enlarged view of the typical shape of thrust washers 12 used in thrust bearing 10 and placed between the collars of the crankshaft 20.

Figure 3 shows the conventional arrangement of washers placed between the crankshaft collars and used for testing the load capability of the thrust bearings on a testing rig at the supplier’s end. It includes a hydraulic ram 52 applying load on a sliding carriage 54 fitted with a torque sensitive fixture 56 which in turn is fitted with a holding fixture 58 for holding a testing part or thrust washer 60. Holding fixture 58 is also provided with an oil passage 62 for supplying oil. A counter face 64 is disposed opposed hydraulic ram 52 and driven by a motor M. However, in the existing method of measurement of the load carrying capability, the testing described above, the testing is not done at the actual application environment, i.e. at the engine level, but at the supplier’s rig which cannot replicate the actual engine application scenario like load, lubrication, temperature, vibration and crankshaft surface finish etc.

Thus, this method can only provide relative load carrying capability with respect to the bearing material and design. This is a major drawback of the existing method of measurement of the load carrying capability of thrust bearings.

Figure 4 shows a schematic arrangement for checking the thrust washer temperature for testing the load carrying capability of thrust bearings on the engine itself by the device 150 configured in accordance with the present invention and thus conducted in an actual application environment. It includes an extension shaft 142 fitted on crankshaft 120 by using bolts 152 (Fig. 6). A crankshaft 120 with collars 122 thereof fitted with a pair of thrust washers 124 of the thrust bearing disposed therebetween. A taper roller bearing 126 with its inner race fitted on the outer diameter of extension shaft 142. The first end of outer bearing cap 128 of thrust bearing 126 is mounted on the outer race of thrust bearing 126. The second end of outer bearing cap 128 is fitted with the first end of extension rod 142 and assembled with a load cell 144 adjacent the first end of extension rod. Accordingly, extension rod 124 extends from the second end of outer bearing cap 128 and carries a load cell 144 thereon. The plate clutch assembly 130 includes a fixed plate 132 and moveable plate 134 and a loading nut 136 disposed on the threaded second end of extension rod 142 for tightening and loosening of clutch assembly 130 thereon. A plurality of compression springs 138 are disposed between fixed plate 132 and moveable plate 134. By tightening or loosening the loading nut 136, moveable plate 134 can be displaced in either direction of double arrow D for pushing or pulling it towards and away from fixed plate 132 (which is mounted on engine cover, e.g. by means of 3 pillars – not shown) to compress or decompress springs 138 to apply load on the thrust bearing 126 for testing the load carrying capability of thrust bearing 126 or for releasing this load. A datalogger 148 is electrically connected to thermocouple 146 on one hand and to load cell 144 on the other hand for capturing and displaying rise in temperature of thrust washers 124 and the corresponding load applied by tightening of loading nut 136. As thrust bearing 126 loading starts, the temperature of thrust washers 124 rises gradually. However, this load is increased in steps, i.e. by tightening of loading nut 136 every time, the operator waits for a few minutes before thrust washers 124 temperature stabilizes. This step-wise load increase is continued till the load carrying capability of thrust bearing 126 is reached, which is evident from a sudden exponential increase in the temperature of thrust washers 124 with a minimal load increase thereafter. This load indicates the thrust bearing failure point. The limiting load used just before this exponential thrust washer temperature increase is termed as the thrust bearing load carrying capacity, because this is the maximum load that thrust washers 124 can carry. Further increase in load would lead to a failure of thrust bearing 126, which in turn would irreparably damage the crankshaft assembly.

Figure 5 shows perspective view of the new arrangement provided for measuring the load carrying capability of thrust bearings according to the present invention. The arrangement includes a bearing cap 128 covering taper roller bearing 126 and fitted on extension shaft 142 of crankshaft 120 (not visible here). Loading plate assembly 130 with fixed plate 132 and moveable plate 134 with springs 138 disposed therebetween is also clearly visible here. Moveable plate 134 can be displaced in either direction of double arrow D by tightening or loosening of loading nut 136 on the threaded end of extension rod 142 for pushing or pulling it towards and away from fixed plate 132 to compress or decompress springs 138 either for applying load on the thrust bearing 126 for testing the load carrying capability of thrust bearing 126 or for releasing this load thereafter for testing the load carrying capability of another crankshaft thrust bearing.

Figure 6 shows an enlarged cross-sectional view of the arrangement of Fig. 5. The arrangement includes a taper roller thrust bearing 126 with an outer bearing cap 128. An oil seal 116 is fitted on extension shaft 140 of crankshaft 120 and a load cell 144 is fitted on the extension rod 142 with a threaded end for tightening or loosening of loading nut 136 thereon.

Figure 7 shows a graphical representation of testing the thrust washer load carrying capability of thrust bearings according to the present invention. Here, friction torque as well as thrust washer temperature slowly increase in a linear fashion, however, suddenly spikes exponentially at the thrust bearing failure load. Accordingly, this exponentially spiked thrust bearing load indicates the thrust bearing failure point. The load used just before this exponentially increased friction torque between the thrust washers 124 and crankshaft collars 122 causes an excessive thrust washer temperature increase, which occurs due to the limitation in the material strength and oil retention capability thereof. This thrust washer failure may irreversibly damage the thrust bearing 126.

This ratio of the thrust bearing failure load to this highest linearly increasing thrust load is defined as the thrust bearing load carrying capability. It is to be noted that during lab-testing, these are the parameters monitored with increase in load using the innovative device.

Here, “P Copper 2” is the sample bearing material. “Friction Torque_P Copper 2” refers to the friction between bearing surfaces measured in terms of torque loss.

“P Copper 2” is bearing material sample, while “T_Temp_P Copper 2” refers to the temperature generated on the bearing surface measured with thermocpouple 146 placed on taper roller bearing 126.

WORKING OF THE INVENTION

The arrangement and device for determining the load carrying capability of thrust bearings in the crankshafts of internal engines is however not limited to the ones disclosed herein.

The arrangement and device for determining the load carrying capability of thrust bearings in the crankshafts of internal combustion engines is used by the method according to the present invention as discussed below:

• Engine is loaded in the testbed and coupled to a dynamometer similar to a regular reliability test.

• Thrust washer loading device is assembled on the front cover of the engine.

• Connection of the thrust bearing to temperature sensor and connection of load cell to configure data logger along with other parameters.

• Engine is warmed-up and thrust bearing is slowly loaded with the help of load cell value displayed.

• Observe gradual temperature rise in thrust washer on thrust bearing loading.

• Increase thrust load step by step and waiting for a few minutes after every loading until stabilization of thrust bearing temperature is achieved.

• The thrust bearing failure point is the load at which an exponential increase in thrust bearing temperature is observed.

• The ratio of earlier load to this failure point defines the Load Carrying Capability of the thrust bearing.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The arrangement and method for measuring the load carrying capability of thrust bearings configured in accordance with the present invention for internal combustion engines, offers the following advantages:

• Testing in actual environment provides a direct application value rather than a derived value of the load carrying capability of the thrust bearing.

• Replicates the actual engine environment, such as lubrication, temperature, vibration, contact depending on the surface finish of crankshaft, etc.

• No special test ring is required, because testing is carried out with regular engine reliability test bed itself.

• Low-cost of testing and testing devices.

• Facilitates capturing friction power for different loads at the engine level.

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

It is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. 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.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification.

Accordingly, the skilled person can make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

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.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply 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.

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.

The description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well as derivatives thereof (e.g. “horizontally”, “downwardly”, “upwardly” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion.

These relative terms are for convenience of description and do not require that the corresponding apparatus or device be constructed or operated in a particular orientation.

Terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship, wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.