Claims:WE CLAIM:

1. A rubber composition to increase a load bearing capacity and a compressibility for a desired stiffness profile for a polymeric spring formed by the rubber composition, the rubber composition comprising:
- a natural rubber 100 phr in weight;
- an accelerator activator ranging from 6 to 8.5 phr in weight;
- a protective agent ranging from 2 to 3 phr in weight;
- a protective wax ranging from 1 to 3 phr in weight;
- an adhesion promoter resins ranging from 1-2 phr in weight;
- a reinforcing carbon black structure grades ranging from 8 to 80 phr in weight;
- a semi-reinforcing and diluent filler ranging from 9 to 33 phr in weight;
- a Plasticizer ranging from 6 to 39 phr in weight;
- a Process improving agent ranging from 0.4 to 3 phr in weight;
- a life enhancer ranging from 3 to 5 phr in weight;
- an accelerator ranging from 1 to 2 phr in weight
- a Vulcanization Agent ranging from 2-3.5 phr in weight;
- anti-scorching agent ranging from 0.1 to 0.4 phr in weight; and
- anti retarder ranging from 0.1 to 0.4 phr in weight.

2. The rubber composition according to claim 1, wherein the accelerator activator is Zn Stearate.

3. The rubber composition according to claim 1, wherein the accelerator activator is combination of ZnO and Stearic acid in a range of 5 to 7 phr and 1 to 1.5 phr in weight respectively.

4. The rubber composition according to claim 1, wherein the protective agent is selected from a group consisting of an antioxidant and an antiozonant, such that each of the antioxidant and the antiozonant are in a range of 1 to 1.5 phr in weight.

5. The rubber composition according to claim 4, wherein the antioxidant is TMQ and the antiozonant is Vulkanox HS.

6. The rubber composition according to claim 1, wherein the protective wax is Paraffin Wax.

7. The rubber composition according to claim 1, wherein the adhesion promoter agent is selected from a group consisting of PF Resin, HMMA and DBC.

8. The rubber composition according to claim 1, wherein the Reinforcing Carbon Black structure grades consists of equal proportions of HAF, FEF and MT.

9. The rubber composition according to claim 1, wherein the semi-reinforcing and diluent filler includes one of clay, Silica and CaCo3.

10. The rubber composition according to claim 1, wherein the plasticizer is selected from a group consisting of Aromatic oil and Naphthenic Oil.

11. The rubber composition according to claim 1, wherein the process improving agents includes Factice in a range of 1 to 3 phr by weight and Renacit-7 in a range of 0.4 to 0.8 phr by weight.

12. The rubber composition according to claim 1, wherein the life enhancer is selected from a group consisting of Sb2O3, Al2O3 and TiO2.

13. The rubber composition according to claim 1, wherein the accelerators include MBT in a range of 0.3 to 0.7 phr by weight, MBTS in a range of 0.5 to 1 phr by weight and TMTD in a range of 0.2 to 0.3 phr by weight.

14. The rubber composition according to claim 1, wherein the vulcanization agent is Sulphur.

15. The rubber composition according to claim 1, wherein the anti-scorching agent is PVI.

16. The rubber composition according to claim 1, wherein the anti- retarder agent is PVS.

17. The rubber composition according to claim 1, wherein the polymeric spring is moulded in the form of a cylindrical structure to further increase the load bearing capacity of the polymeric spring.

18. The rubber composition according to claim 17, wherein the cylindrical structure is made tapered to have a concave shape in a central portion along an axial length of the cylindrical structure.

19. The rubber composition according to claim 17, wherein the cylindrical structure is provided with annular ring structures on its surface along an axial length of the cylindrical structure, such that the annular rings are perpendicular to the axis of the cylindrical structure.

20. The rubber composition according to claim 1, wherein the rubber composition, the rubber composition comprises:
- the natural rubber 100 phr in weight;
- the accelerator activator 5 phr in weight;
- the protective agent 2 phr in weight;
- the protective wax 1.5 phr in weight;
- the adhesion promoter resins 1 phr in weight;
- the reinforcing carbon black 24 phr in weight;
- the semi-reinforcing and diluent filler 12 phr in weight;
- the Plasticizer 12 phr in weight;
- the Process improving agent 2 phr in weight;
- the life enhancer 4 phr in weight;
- the accelerator 1.5 phr in weight;
- the Vulcanization Agent 2.5 phr in weight;
- the anti-scorching agent 0.2 phr in weight; and
- the anti-retarder 0.2 phr in weight.

, Description:FIELD OF THE INVENTION

[001] The present invention relates in general to polymeric springs and more particularly, to a rubber composition for improving the properties of a polymeric spring.

BACKGROUND OF THE INVENTION

[002] Springs are widely used in many industries for their dynamic and mechanical properties. For example, large springs are used in the automotive industry and smaller springs are used for electronic and mechanical devices. In most of the applications, steel springs are used because of their quality of fabrication, stiffness, strength, and mass production ability. However, steel springs tend to be relatively heavier and disadvantageous to be used in certain applications where weight and size is a limitation. For example, in applications such as automobiles, airplanes, railway cars, heavy load weighing, constructions, seismic mountings, shock absorbers and load bearings, it is critical to reduce the weight of various components to reduce the overall weight and compactness of the system.

[003] Other drawbacks of steel springs include their limited corrosion resistance, fatigue strength, high coefficient of thermal expansion, magnetic properties, and electrically conductive nature which can pose problems in application where these properties are undesired.

[004] One approach to obviate some of the drawbacks of steel springs is to form single helical springs from composite materials. Single helical springs formed of composite materials have been developed, to take advantage of light weight characteristics of plastic materials. However, these types of springs fail to provide sufficient stiffness to replace steel springs. A single helical spring is a torsion bar wrapped into a helical form, and the stiffness of a torsion bar is determined by the shear modulus of elasticity of the material. As the shear modulus of composite materials is much smaller than the shear modulus of steel, the stiffness of a single helical composite spring is much less than that of a single helical spring made of steel.

[005] Other forms of rubber springs are also known for suspension systems, these generally comprise a block of rubber generally of cylindrical form having opposed flat end faces which in use are subjected to compression. In order to obtain required compression characteristics for rubber springs of substantial length, it is usually arranged that the spring should compress in such manner as to form a plurality of bulges or convolutions along its length. This allows the compressive, and other forces in the material, to be distributed along the length of the spring, rather than being over-much concentrated in one region. For this purpose the exterior of the rubber spring has commonly been provided with circumferential depressions or waists at one or more transverse planes along the length of the spring.

[006] Polymeric springs (also refereed in this document as ‘rubber springs’) have different spring properties based on the rubber composition used to make the rubber springs. Typically, polymeric springs provide force/deflection curves which vary depending on the material and configuration of the spring. For a polymeric spring, the term "stiff" refers to that portion of the force versus deflection curve that has relatively high spring rate, whether constant slope or generally rising rate and is characteristic of progressively increasing resistance to compressive deformation. Similarly, the term "soft" refers to and is characteristic of relatively lower spring rate or less resistance to compressive deformation, whether increasing, decreasing or none.

[007] Polymeric compression springs pose challenges in controlling the spring rate. Stiffness or hardness is reflected by the load-deflection curve of a polymeric spring. A high spring rate is identified with stiffness of the spring being the relationship of a load and the deflection caused by it as exemplified by the tangent to the deflection curve at that particular load. A high spring rate is therefore denoted by a steep tangent, a steep deflection curve and a hard spring; conversely a low spring rate denotes a soft spring i.e. a greater deflection.

[008] The ‘load bearing capacity’ of a polymeric spring is the maximum load it can handle without losing its elastic properties, the ‘compressibility’ is the ability of the polymeric spring to change in dimensions on application of force on the polymeric spring without losing its elastic properties. A polymeric spring which can undergo large change in dimensions on application of force is said to have good compressibility. The stiffness is the slope of the force-deflection curve at any point.

[009] Referring to Fig. 1, a representative force-deflection curve for models made of two different rubber compositions R1, R2 and steel spring ‘S’ is shown. The rubber compositions R1, R2 were prepared and tested as per ASTM standards. Cylindrical models of same shape and size using the rubber compositions R1, R2 were made to have all initial conditions same. Now the rubber models made from R1, R2 were compressed by applying force and the deflection is measured and the curves were plotted. The curve R1 representing the model of rubber composition ‘R1’ shows steep increase in force with the deflection almost constant, the spring is stiff which means that, it has good load bearing capacity but low compressibility. The curve R2 representing the model of rubber composition ‘R2’ shows that, the deflection increases without much change in force after a certain time. The spring made by R2 is soft, which means though it has good compressibility, but the load bearing capacity is bad.

[0010] The curve ‘S’ is a straight line showing the steel material behaviour in which the force and deflection is proportional and predictable, which is not the case with R1 and R2 rubber composition models. It is desirable to achieve the steel spring stiffness profile by using a rubber composition.

[0011] For some applications high load bearing capacity with high compressibility in a spring is required within a small space, which is not possible by use of steel springs because of its huge dimensions and weight. For high load bearing capacity in order to obtain lower spring rate and higher deflection, the length of steel spring need to be increased substantially resulting in a laterally unstable and impractical structure that causes buckling.

[0012] In view of the limitations inherent in the available polymeric springs, there exists a need for an improved rubber composition for making the polymeric spring having desired load-deflection characteristics, which overcomes the disadvantages of the prior art and which can be used in a simple, compact, lightweight, cost effective, reliable, secure and environmentally friendly manner.

[0013] The present invention fulfils this need and provides further advantages as described in the following summary.

SUMMARY OF THE INVENTION

[0014] In view of the foregoing disadvantages inherent in the prior arts, the general purpose of the present invention is to provide an improved combination of convenience and utility, to include the advantages of the prior art, and to overcome the drawbacks inherent therein.

[0015] A primary objective of the present invention is to provide a device for static or dynamic loading causing spring action in compression or tension mode operation which is simple, light weight, compact and cost effective.

[0016] In one aspect, the present invention provides a rubber composition to increase a load bearing capacity and a compressibility for a desired stiffness profile for a polymeric spring formed by the rubber composition. The rubber composition comprises natural or gum rubber, an accelerator activator, a protective agent, a protective wax, an adhesion promoter resins, a reinforcing carbon black structure grades, a semi-reinforcing and diluent filler, a Plasticizer, a Process improving agent, a life enhancer, an accelerator, a Vulcanization Agent, anti-scorching agent and anti-retarder agent.

[0017] In another aspect of the present invention, the accelerator activator is combination of ZnO and Stearic acid in a range of 5 to 7 phr and 1 to 1.5 phr in weight respectively.

[0018] In yet another aspect of the present invention, the protective agent is selected from a group consisting of an antioxidant and an antiozonant, such that each of the antioxidant and the antiozonant are in a range of 1 to 1.5 phr in weight.

[0019] In a further aspect of the present invention, the adhesion promoter resins agent is selected from a group consisting of PF Resin, HMMA and DBC-Power Plast.

[0020] In another aspect of the present invention, the Reinforcing Carbon Black structure grades consists of equal proportions of HAF, FEF and MT.

[0021] In yet another aspect of the present invention, the semi-reinforcing and diluent filler includes one of clay, Silica, CaCo3.

[0022] In another aspect of the present invention, the process improving agents includes Factice in a range of 1 to 3 phr by weight and Renacit-7 in a range of 0.4 to 0.8 phr by weight.

[0023] In yet another aspect of the present invention, the accelerators include MBT in a range of 0.3 to 0.7 phr by weight, MBTS in a range of 0.5 to 1 phr by weight and TMTD in a range of 0.2 to 0.3 phr by weight.

[0024] In one aspect of the present invention, the polymeric spring is moulded in the form of a cylindrical structure to further increase the load bearing capacity of the polymeric spring.

[0025] In another aspect of the present invention, the cylindrical structure is made tapered to have a concave shape in a central portion along an axial length of the cylindrical structure.

[0026] In yet another aspect of the present invention, the cylindrical structure is provided with annular ring structures on its surface along an axial length of the cylindrical structure, such that the annular rings are perpendicular to the axis of the cylindrical structure.

[0027] These together with other aspects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the description annexed here to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The advantages and features of the present invention will become better understood with reference to the following more detailed description taken in conjunction with the accompanying drawings in which:

[0029] FIG. 1 illustrates a representative force-deflection curve for polymeric springs made of different rubber compositions R1, R2 and steel spring ‘S’; according to state of the art;

[0030] FIG. 2 illustrates a force-deflection curve of metallic spring and polymeric spring made by rubber composition of the present invention, according to one embodiment of the present invention;

[0031] FIG. 3 illustrates a schematic diagram of a polymeric spring made by rubber composition of the present invention, according to one embodiment of the present invention;

[0032] FIG. 4 illustrates a schematic diagram of a polymeric spring made by rubber composition of the present invention, according to another embodiment of the present invention; and

[0033] FIG. 5 illustrates a schematic diagram of a polymeric spring made by rubber composition of the present invention, according to yet another embodiment of the present invention;

[0034] Like reference numerals refer to like parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

[0035] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.

[0036] As used herein, the term ‘plurality’ refers to the presence of more than one of the referenced item and the terms ‘a’, ‘an’, and ‘at least’ do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0037] Reference herein to “one embodiment” or “another embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the diagrams representing one or more embodiments of the invention do not inherently indicate any particular order nor imply any limitations in the invention.

[0038] The rubber composition of the present invention is used to increase a load bearing capacity and a compressibility for a desired stiffness profile for a polymeric spring formed by the rubber composition. The rubber composition comprises natural rubber 100 phr in weight, an accelerator activator ranging from 6 to 8.5 phr in weight, a protective agent ranging from 2 to 3 phr in weight, a protective wax ranging from 1 to 3 phr in weight, an adhesion promoter resins ranging from 1-2 phr in weight, a reinforcing carbon black ranging from 8 to 80 phr in weight, a semi-reinforcing and diluent filler ranging from 9 to 33 phr in weight, a Plasticizer ranging from 6 to 39 phr in weight, a Process improving agent ranging from 0.4 to 3 phr in weight, a life enhancer ranging from 3 to 5 phr in weight, an accelerator ranging from 1 to 2 phr in weight, a Vulcanization Agent ranging from 2-3.5 phr in weight, anti-scorching agent ranging from 0.1 to 0.4 phr in weight and anti-retarder agent ranging from 0.1 to 0.4 phr in weight.

[0039] The above rubber composition of the present invention provides Shore °A Hardness ranging from 30-90, for fulfillment of a range of compressibility, load bearing capacity and stiffness properties for optimal properties requirement as per the application.

[0040] Natural rubber or gum is used in the present invention. Natural rubber or gum is the base polymer resin of monomer units with high molecular weight/ oligomers chains to polymerization of matrix for polymer backbone formations. In one embodiment of the present invention, the natural rubber used is in the form of Pale Crepe or Smoked Sheet. Pale latex crepe (PLC) is a premium grade natural rubber made from raw field latex. Ribbed Smoked Sheets (RSS) are coagulated rubber sheets processed from fresh field latex sourced from well managed rubber plantations adopting modern processing methods.

[0041] The accelerator activator is used to activate the accelerator for participation in the polymerization reaction or to initiate the rate of reaction of catalyst/ dispersant for the polymer matrix. In one embodiment of the present invention, the accelerator activator is Zn Stearate. In another embodiment of the present invention, the accelerator activator is a combination of ZnO and Stearic acid in a range of 5 to 7 phr and 1 to 1.5 phr in weight respectively.

[0042] The function of protective agents is to protect the polymeric spring from environmental Oxygen and Ozone attack on unsaturated double bonds or free radical/ free ions present into polymer matrix during service life as function of staining/ non-staining mode. In one embodiment of the present invention, the protective agent is selected from a group consisting amine/thioester as primary or secondary type an antioxidant and an antiozonant, such that each of the antioxidant and the antiozonant are in a range of 1 to 1.5 phr in weight. In one preferred embodiment of the present invention, the antioxidant is TMQ and the antiozonant is Vulkanox HS.

[0043] The protective wax is used in the rubber composition to protect the polymer from external harsh environment, by forming a thin masking layer on the polymer matrix material. In one embodiment of the present invention, the protective wax is Paraffin Wax.

[0044] The adhesion promoter agent enhances the adhesion/ tackifier properties of polymer matrix for adhesiveness with metal/ other rigid substrates. In one embodiment of the present invention, the adhesion promoter agent is selected from a group consisting of PF Resin, HMMA and DBC - Power Plast.

[0045] The reinforcing carbon black is used to enhance/ reinforce the mechanical strength/ holding properties of polymer matrix around 4 to 5 times of Base polymer matrix. In one embodiment of the present invention, the Reinforcing Carbon Black structure grades consists of equal proportions of HAF, FEF and MT. In one preferred embodiment of the present invention, the Reinforcing Carbon Black structure grades consists of equal proportions of HAF (N339), FEF (N550) and MT (N990).

[0046] The semi-reinforcing and diluent filler is added in the rubber composition to incorporate viscosity control, increase the volume and rigidity of polymer material and reduce the cost. In one embodiment of the present invention, the semi-reinforcing and diluent filler includes one of clay, Silica, and CaCO3.

[0047] The plasticizer is used as lubricant for ease of processability by adjusting the viscosity and enhances the flexibility/softness of the polymer matrix by parallel short chains formations. In one embodiment of the present invention, the plasticizer is selected from a group consisting of Aromatic oil and Naphthenic Oil.

[0048] The process improving agents are added for enhancing the processability, dimensional stability, glassiness/ non-stickiness, flow property of polymer matrix during the process of polymer formation. In one embodiment of the present invention, the process improving agents includes Factice in a range of 1 to 3 phr by weight and peptizer – Renacit 7 in a range of 0.4 to 0.8 phr by weight.

[0049] The life enhancer is used to enhance life of the polymer by enhancing resistance to thermal/fire conditions and inhibiting the effects of UV/ flex/ cracking etc. In one embodiment of the present invention, the life enhancer is selected from a group consisting of Sb2O3, Al2O3 and TiO2.

[0050] The accelerators accelerate and control the cross-linking reaction rate during polymerization for boosting the reaction. Based on the reaction time, boosting required primary, secondary or ternary accelerators may be used. In one preferred embodiment of the present invention, the accelerators include MBT in a range of 0.3 to 0.7 phr by weight, MBTS in a range of 0.5 to 1 phr by weight and TMTD in a range of 0.2 to 0.3 phr by weight.

[0051] The vulcanization agent is the main catalyst in the vulcanization reaction to crosslink the polymer chain/ polymer matrix by strong covalent bonds. In one preferred embodiment of the present invention, the vulcanization agent is Sulphur.

[0052] The anti-scorching agent is a pre-vulcanization inhibitor. It provides predictable scorch control in most sulphur vulcanization and improved quality performance through marginal stock recovery, single-stage mixing, higher processing and/ or curing temperatures. It is used to control the reaction initiation rate for material storage safety and quality production before/ during processing. In one embodiment of the present invention, the anti-scorching agent is PVI.

[0053] The anti-retarder agent is a post vulcanization stabilizer, A single-stage mixing, higher processing and/ or curing temperatures, It is used to control the reaction termination rate for optimal saturation for quality production and prevent reversion/ degradation during processing/ latent curing. In one embodiment of the present invention, the rubber composition includes anti- retarder agent as PVS.

[0054] In one preferred embodiment of the present invention, the rubber composition includes natural rubber 100 phr in weight, accelerator activator 5 phr in weight, protective agent 2 phr in weight, protective wax 1.5 phr in weight, adhesion promoter resins 1 phr in weight, reinforcing carbon black 24 phr in weight, semi-reinforcing and diluent filler 12 phr in weight, Plasticizer 12 phr in weight, Process improving agents 2 phr in weight, life enhancer 4 phr in weight, accelerator 1.5 phr in weight, Vulcanization Agent 2.5 phr in weight, anti-scorching agent 0.2 phr in weight and anti-retarder 0.2 phr in weight.

[0055] The rubber composition of the present invention (also referred in the present description as ‘RF’) is tested by making a sample and tested as per the ASTM standards to obtain a stress-strain curve. Cylindrical model having same shape and size like the models of the rubber compositions R1, R2 is made and all initial conditions are kept same. Now the rubber models made from RF is compressed by applying force and the deflection is measured and the curve is plotted. The sample is tested for iterative loading and one mean curve is selected to represent the properties of the rubber composition in the form of stress-strain curve ‘RF’ as shown in FIG.1. It is observed that the rubber composition of the present invention ‘RF’ gives better stiffness profile and compressibility as compared to the rubber compositions ‘R1’, ‘R2’ and is much near to the steel material profile ‘S’.

[0056] This rubber composition ‘RF’ is used to make a polymeric spring. The stress-strain curve obtained is fed as property of material into a Finite Element Analysis simulation. In one embodiment of the present invention, the polymeric spring is moulded in the form of a cylindrical structure as shown in FIG. 3 to further increase the load bearing capacity of the polymeric spring. A cylindrical shaped polymeric spring is made from using the properties of rubber composition ‘RF’ and load and boundary conditions are applied on it and analysed to obtain the force deflection curve. It is observed that the polymeric spring formed by rubber composition of the present invention ‘RF’ gives better stiffness profile and is much closer to the steel spring profile ‘S’ as shown in the graph of FIG. 2.

[0057] The cylindrical shape of the polymeric spring is further optimized to achieve required dimensions and properties for the polymeric spring made from the rubber composition of the present invention. In one embodiment of the present invention, the cylindrical structure is made tapered to have a concave shape on lateral surface/ in a central portion along an axial length of the cylindrical structure as shown in FIG.4. In another embodiment of the present invention, the cylindrical structure is provided with annular ring structures on its surface along an axial length of the cylindrical structure, such that the annular rings are perpendicular to the axis of the cylindrical structure as shown in FIG.5. It is to assure structural stability and compensate bulging that may happen during uneven lading for various reasons like shims/ end plates flatness. Thus the rubber composition of the present invention ‘RF’ improves the properties of the earlier rubber compositions like R1 and R2 and by molding the polymer spring made by ‘RF’ in the shapes as suggested by present invention, further improves the spring properties to obtain stiffness profile of the polymeric spring closer to the metallic spring ‘S’.

[0058] It is to be noted that the shapes of the polymeric spring made from the rubber composition of the present invention as shown in FIGs. 3,4 and 5 are some of the shapes and are not limitations for the polymeric spring shapes. Though not disclosed, but a number of other shapes with or without additions of some metallic/ composite parts as reinforcement is also part of the present invention if the polymeric spring is made with the rubber composition of the present invention.

[0059] The polymeric spring made by rubber composition of the present invention provide advantages as below:
- Reduced Weight: The weight of the polymeric spring is reduced up to 50% as compared to the steel spring.
- Better compressibility: The rubber composition of the present invention has made it possible to use rubber to make a spring which can provide compressibility up to 60% under heavy duty load applications
- Corrosion Free: The polymeric spring is corrosion free for entire life of the spring
- Field Repairable Assemblies: Safe and convenient installation of polymeric makes the system repairable on site
- Stable geometries: The optimized shapes of the polymeric springs provide stable geometry with higher compressibility and reduced bulging for various complex applications
- Extrusion based manufacturing: The shapes of the springs can be produced by continuous extrusion process for reduced manufacturing cost.

[0060] Although a particular exemplary embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized to those skilled in the art that variations or modifications of the disclosed invention, including the rearrangement in the configurations of the parts, changes in steps and their sequences may be possible. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the present invention.

[0061] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching.

[0062] 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 understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.