阅读说明：本技术 车辆用复合材料型多板弹簧悬架 (Composite material type multi-plate spring suspension for vehicle ) 是由 吴胜贤 于 2018-11-28 设计创作，主要内容包括：本发明涉及一种车辆用复合材料型多板弹簧悬架,包括：第一支架单元,其安装在橡胶弹簧上；第二支架单元,其安装在平衡轴基座上；以及多个复合弹簧,其通过用树脂浸渍增强纤维制造而成,分别在其相反两端与第一支架单元和第二支架单元联接,并且彼此竖直间隔开。(The invention relates to a composite material type multi-plate spring suspension for a vehicle, comprising: a first bracket unit mounted on the rubber spring; a second bracket unit mounted on the balance shaft base; and a plurality of composite springs manufactured by impregnating reinforcing fibers with resin, coupled with the first and second bracket units at opposite ends thereof, respectively, and vertically spaced apart from each other.)

1. A composite type multi-leaf spring suspension for a vehicle, the spring suspension comprising:

a first bracket unit mounted on the rubber spring;

the second bracket unit is arranged on the balance shaft base; and

a plurality of compound springs, opposite ends of which are coupled to the first and second stand units, respectively, the plurality of compound springs being vertically spaced apart from each other.

2. The spring suspension of claim 1, wherein:

the compound spring comprises an upper spring and a lower spring,

the first rack unit includes: a first upper bracket coupled to a first end of the upper spring; and a first lower bracket connected to a lower portion of the first upper bracket to be coupled with a first end of the lower spring, and

the second rack unit includes: a second upper bracket coupled to a second end of the upper spring; and a second lower bracket coupled to a second end of the lower spring.

3. The spring suspension of claim 2, wherein:

the first upper bracket includes: a first upper plate disposed to contact an upper surface of a first end portion of the upper spring; a first lower plate spaced apart from the first upper plate below the first upper plate to contact a lower surface of a first end portion of the upper spring; and a first side plate configured to connect the first upper plate and the first lower plate to each other, and

the first lower bracket includes: a second upper plate disposed in contact with an upper surface of the first end portion of the lower spring; a second lower plate spaced apart from the second upper plate below the second upper plate to contact a lower surface of the first end portion of the lower spring; and a second side plate configured to connect the second upper plate and the second lower plate to each other.

4. The spring suspension of claim 3, wherein:

the first stand unit further includes a connection member connecting the first upper stand and the first lower stand to each other, and

the connecting member is configured to couple the first side plate and the second side plate together to connect the first upper bracket and the first lower bracket to each other.

5. The spring suspension of claim 3, wherein:

the first side plate is configured to protrude downward from the first lower plate and to be in contact with an upper surface of the second side plate, and

a connecting member is configured to couple the first and second side plates together by passing vertically through the first and second side plates.

6. The spring suspension of claim 5, wherein:

the upper end of the rubber spring is provided with a rubber spring support which is contacted with the lower surface of the first lower support, and

the lower end of the connection member passes through the rubber spring holder to connect the first lower holder and the rubber spring to each other.

7. The spring suspension of claim 3, wherein the first carrier unit further comprises:

a first fixing member configured to sequentially pass through the first upper plate, the upper spring, and the first lower plate to fix a first end portion of the upper spring to the first upper bracket; and is

A second fixing member configured to sequentially pass through the second upper plate, the lower spring, and the second lower plate to fix a first end portion of the lower spring to the first lower bracket.

8. The spring suspension of claim 2, wherein:

the second stand unit further includes a support coupled to the balance shaft base and extending in an up-and-down direction,

the second upper bracket includes: a third upper plate extending from the support to contact an upper surface of the second end of the upper spring; and a third lower plate spaced apart from the third upper plate below the third upper plate and extending from the support to contact a lower surface of the second end of the upper spring, and

the second lower bracket includes: a fourth upper plate spaced apart from the third lower plate below the third lower plate and extending from the supporter to contact an upper surface of the second end portion of the lower spring; and a fourth lower plate spaced apart from the fourth lower plate below the fourth upper plate and extending from the supporter to contact a lower surface of the second end portion of the lower spring.

9. The spring suspension of claim 8, wherein the second carrier unit further comprises:

a third fixing member configured to sequentially pass through the third upper plate, the upper spring, and the third lower plate to fix a second end portion of the upper spring to the second upper bracket; and is

A fourth fixing member configured to sequentially pass through the fourth upper plate, the lower spring, and the fourth lower plate to fix a second end of the lower spring to the second lower bracket.

10. The spring suspension of claim 1, wherein:

the rubber springs are configured such that a pair of rubber springs are provided to be installed at opposite sides of the balance shaft base,

the first holder unit is configured such that a pair of first holder units are provided to be mounted on the pair of rubber springs, respectively, and

the compound spring is disposed between the first and second stand units.

11. The spring suspension of claim 1, wherein:

the composite spring is divided into opposite end portions coupled to the first and second stand units, respectively, and an intermediate portion formed between the opposite end portions, and

the opposite end portions have a width in the vehicle width direction smaller than a width of the intermediate portion in the vehicle width direction.

12. The spring suspension of claim 1, wherein the composite spring is manufactured by impregnating reinforcing fibers with resin.

13. The spring suspension according to claim 12, wherein the reinforcing fibers included in the upper spring and the lower spring include a plurality of first fibers arranged perpendicularly to the vehicle width direction.

14. The spring suspension of claim 13, wherein the reinforcing fibers included in the lower spring further include a plurality of second fibers arranged to cross the first fibers.

Technical Field

The present invention relates generally to a composite-material-type multi-leaf spring suspension for a vehicle, and more particularly, to a multi-leaf spring suspension that is capable of elastically coordinating between a vehicle body and an axle using a composite spring.

Background

Generally, in commercial vehicles, a leaf spring is connected between two axles to elastically coordinate between a balance shaft base and the axles.

Conventionally, in the case of using a suspension structure having a leaf spring made of a metal material, when a vehicle is suddenly stopped, a winding phenomenon occurs in which leaf springs on both sides rotate in opposite directions around a balance shaft base. If the wind phenomenon occurs, the vehicle body is severely inclined forward, or the load is concentrated on the spring and the vehicle body, thereby causing damage.

Meanwhile, a technique has been developed in which a composite material type spring made of resin-impregnated reinforcing fibers is used instead of the conventional metal material plate spring. The composite spring is light in weight, contributes to weight reduction of a vehicle, and has good tensile strength and elasticity, and thus can replace a conventional leaf spring.

However, it is difficult to use the bolting method due to the material characteristics of the composite spring, and it is difficult to apply a bolted multi-layer structure like a plate spring because the composite spring is easily damaged by friction.

Therefore, a composite spring is used instead of the multi-plate type plate spring, and if the composite spring is damaged, the vehicle cannot travel.

Therefore, there is a need for a suspension structure using multi-plate type compound springs that can support a vehicle body by one compound spring even when the other compound spring is damaged, while preventing damage due to bolting or friction.

The foregoing is intended only to aid in understanding the background of the invention and is not intended to represent that the invention falls within the scope of the relevant art as known to those skilled in the art.

Disclosure of Invention

Accordingly, the present invention provides a composite material type multi-plate spring suspension having a plurality of composite springs, thereby enabling a vehicle to travel even if one of the plurality of composite springs is damaged.

In order to achieve the above object, there is provided a multi-plate spring suspension of a composite material type, the spring suspension comprising: a first bracket unit mounted on the rubber spring; a second bracket unit mounted on the balance shaft base; and a plurality of complex springs coupled with the first and second stand units at opposite ends thereof, respectively, and vertically spaced apart from each other.

The compound spring may include an upper spring and a lower spring, and the first stand unit may include: a first upper bracket coupled to a first end of the upper spring; and a first lower bracket connected to a lower portion of the first upper bracket to be coupled with a first end of the lower spring, and the second bracket unit may include: a second upper bracket coupled to a second end of the upper spring; and a second lower bracket coupled to a second end of the lower spring.

The first upper bracket may include: a first upper plate disposed in contact with an upper surface of the first end portion of the upper spring; a first lower plate spaced apart from the first upper plate below the first upper plate to contact a lower surface of the first end of the upper spring; and a first side plate configured to connect the first upper plate and the first lower plate to each other, and the first lower bracket may include: a second upper plate disposed in contact with an upper surface of the first end portion of the lower spring; a second lower plate spaced apart from the second upper plate below the second upper plate to contact a lower surface of the first end portion of the lower spring; and a second side plate configured to connect the second upper plate and the second lower plate to each other.

The first bracket unit may further include a connecting member connecting the first upper bracket and the first lower bracket to each other, and the connecting member may be configured to couple the first side plate and the second side plate together to connect the first upper bracket and the first lower bracket to each other.

The first side plate may be configured to protrude downward from the first lower plate and to contact an upper surface of the second side plate, and the connecting member may be configured to couple the first side plate and the second side plate together by vertically passing through the first side plate and the second side plate.

An upper end of the rubber spring may be provided with a rubber spring supporter contacting a lower surface of the first lower supporter, and a lower end of the connection member may penetrate the rubber spring supporter to connect the first lower supporter and the rubber spring to each other.

The first stand unit may further include: a first fixing member configured to sequentially pass through the first upper plate, the upper spring, and the first lower plate to fix a first end of the upper spring to the first upper bracket; and a second fixing member configured to sequentially pass through the second upper plate, the lower spring, and the second lower plate to fix the first end portion of the lower spring to the first lower bracket.

The second stand unit may further include a support coupled to the balance shaft base and extending upward and downward, and the second upper stand may include: a third upper plate extending from the support to contact an upper surface of the second end of the upper spring; and a third lower plate spaced apart from the third upper plate below the third upper plate and extending from the support to contact a lower surface of the second end portion of the upper spring, and the second lower bracket may include: a fourth upper plate spaced apart from the third lower plate below the third lower plate and extending from the supporter to contact an upper surface of the second end portion of the lower spring; and a fourth lower plate spaced apart from the fourth upper plate below the fourth upper plate and extending from the support to contact a lower surface of the second end portion of the lower spring.

The second rack unit may further include: a third fixing member configured to sequentially pass through the third upper plate, the upper spring, and the third lower plate to fix the second end of the upper spring to the second upper bracket; and a fourth fixing member configured to sequentially pass through the fourth upper plate, the lower spring, and the fourth lower plate to fix the second end of the lower spring to the second lower bracket.

The rubber springs may be configured such that a pair of the rubber springs are disposed to be respectively installed at opposite sides of the balance shaft base, the first stand unit may be configured such that a pair of the first stand units are disposed to be respectively installed to the rubber springs, and the complex spring may be disposed between the first stand unit and the second stand unit.

The compound spring may be divided into opposite end portions connected to the first and second stand units, respectively, and a middle portion formed between the opposite end portions, and a width of the opposite end portions in the vehicle width direction may be smaller than a width of the middle portion in the vehicle width direction.

The composite spring may be manufactured by impregnating reinforcing fibers with a resin.

The reinforcing fibers included in the upper spring and the lower spring may include a plurality of first fibers arranged perpendicular to the vehicle width direction.

The reinforcing fiber included in the lower spring may further include a plurality of second fibers arranged to cross the first fibers.

The composite-type multi-leaf spring suspension according to the invention has the following advantages.

First, the spring suspension includes a plurality of compound springs, so that the vehicle can travel even if one of the plurality of compound springs is damaged.

Second, by preventing friction between the compound springs, the life thereof can be increased.

Third, by shortening the length of the compound spring, the durability of the spring can be improved and the winding phenomenon can be prevented.

Drawings

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of a composite-type multi-leaf spring suspension according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view illustrating a composite type multi-leaf spring suspension according to an embodiment of the present invention;

FIG. 3 is a perspective view illustrating a composite type multi-leaf spring suspension according to an embodiment of the present invention; and

fig. 4 is a perspective view illustrating a composite material type multi-plate spring suspension according to another embodiment of the present invention.

Detailed Description

It is understood that the term "vehicle" or "vehicular" or other similar terms as used herein include motor vehicles in general, such as passenger vehicles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as a vehicle that has both gasoline power and electric power.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the word "and/or" includes any and all combinations of one or more of the associated listed items. Throughout this specification, unless explicitly described to the contrary, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Further, the terms "unit", "piece", "device", and "module" described in the specification mean a unit that processes at least one function and operation, and may be implemented by hardware or software, and a combination thereof.

Furthermore, the control logic of the present invention may be embodied as a non-transitory computer readable medium on a computer readable medium containing executable program instructions for execution by a processor, controller, or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, Compact Disc (CD) -ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer readable medium CAN also be distributed over a network coupled computer systems so that the computer readable medium is stored and executed in a distributed fashion, such as through a telematics server or Controller Area Network (CAN).

Unless defined otherwise, all terms including technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Those terms defined in commonly used dictionaries should be interpreted as having the same meaning as the context in the relevant art. Unless expressly defined in this application, these terms should not be construed as having an idealized or overly formal meaning.

Hereinafter, a composite material type multi-plate spring suspension according to an exemplary embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a side view of a composite-type multi-leaf spring suspension according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view illustrating a composite type multi-leaf spring suspension according to an embodiment of the present invention; and figure 3 is a perspective view showing a composite type multi-leaf spring suspension according to an embodiment of the present invention.

As shown in fig. 1 to 3, an embodiment of a composite-type multi-plate spring suspension according to the present invention includes: a first bracket unit 200 mounted to the rubber spring 10; a second bracket unit 300 mounted to the balance shaft base 20; and a plurality of composite springs 100 manufactured by impregnating reinforcing fibers with resin, opposite ends of which are connected to the first and second stand units 200 and 300, respectively, and are vertically spaced apart from each other.

The rubber spring 10 mentioned here is mounted on the axle of the commercial vehicle to elastically absorb the impact transmitted from the ground, and the balance shaft base 20 is configured to uniformly distribute the load of the vehicle body to each axle.

The composite spring 100 is manufactured by impregnating reinforcing fibers with resin. Here, it is preferable that the reinforcing fiber is arranged in a predetermined direction to be an anisotropic type having an enhanced rigidity in a specific direction.

Each of the first and second stand units 200 and 300 is formed with a groove to receive opposite ends of the compound spring 100 therein and couple them together.

Here, the first and second stand units 200 and 300 are formed with a plurality of grooves into which each of the compound springs 100 is inserted, whereby the plurality of compound springs 100 can be coupled between the first and second stand units 200 and 300 while being spaced apart from each other. For example, compound spring 100 may include an upper spring 110 and a lower spring 120.

The first stand unit 200 may be roughly divided into a first upper stand 210 and a first lower stand 220, and the first upper stand 210 and the first lower stand 220 may be integrally formed by being connected to each other by a connection member 230.

The first upper bracket 210 is formed with a groove into which the first end of the upper spring 110 is inserted, and the first lower bracket 220 is formed with a groove into which the first end of the lower spring 120 is inserted.

Specifically, the first upper bracket 210 includes a first upper plate 211, a first lower plate 212, and a first side plate 213, wherein the first upper plate 211 is disposed in contact with an upper side surface of the first end of the upper spring 110, the first lower plate 212 is disposed in contact with a lower side surface of the first end of the upper spring 110, and the first side plate 213 connects the ends of the first upper plate 211 and the first lower plate 212 together. Accordingly, the first upper holder 210 is integrally formed as a U-shaped groove into which the first end of the upper spring 110 is inserted.

Here, the lower end of the first side plate 213 is configured to protrude lower than the first lower plate 212, and a through hole is formed in the first side plate 213. The inner side of the through-hole may be formed with a screw thread. The first upper bracket 210 may be formed in an F-shape when the first side plate 213 protrudes downward from the first lower plate 212.

The first lower bracket 220 includes a second upper plate 221, a second lower plate 222, and a second side plate 223, similar to the first upper bracket 210, wherein the second upper plate 221 is disposed to contact an upper side surface of the first end portion of the lower spring 120, the second lower plate 222 is disposed to contact a lower side surface of the first end portion of the lower spring 120, and the second side plate 223 connects the second upper plate 221 with an end portion of the second lower plate 222. Accordingly, the first lower holder 220 is integrally formed as a U-shaped groove into which the first end of the lower spring 120 is inserted.

The upper end of the second side plate 223 is formed to be in close contact with the lower end of the first side plate 213, and the second side plate 223 is provided with a through hole vertically formed therein to communicate with the through hole of the first side plate 213.

The connecting member 230 simultaneously passes through the through holes of the first and second side plates 213 and 223 to connect the first and second side plates 213 and 223, thereby coupling the first upper bracket 210 and the first lower bracket 220 together. The connection member 230 may be a bolt or a rivet, and when the connection member 230 is a bolt, it may be fastened using threads formed on the inner sides of the through holes of the first and second side plates 213 and 223.

Here, since the first side plate 213 protrudes lower than the first lower plate 212, the grooves respectively formed in the first upper bracket 210 and the first lower bracket 220 are formed to be spaced apart from each other, whereby the upper spring 110 and the lower spring 120 can be maintained to be spaced apart from each other at a predetermined interval.

Meanwhile, the upper end of the rubber spring 10 is formed with a rubber spring holder 11 contacting the lower surface of the first lower holder 220, and the rubber spring holder 11 is formed with a through hole communicating with the through hole formed in the first side plate 213, whereby the lower end portion of the connection member 230 passes through the through hole formed in the rubber spring holder 11 to integrally fix the first lower holder 220 and the rubber spring 10.

Accordingly, the first bracket unit 200 is fixed to the rubber spring 10 so that the first ends of the upper and lower springs 110 and 120 can be coupled to the upper end of the rubber spring 10.

Further, it is preferable that the first stand unit 200 further includes: a first fixing member 214 sequentially passing through the first upper plate 211, the first end of the upper spring 110, and the first lower plate 212 to fix the upper spring 110 to the first upper bracket 210; and a second fixing member 224 sequentially passing through the second upper plate 221, the first end portion of the lower spring 120, and the second lower plate 222 to fix the lower spring 120 to the first lower bracket 220.

The first and second fixing members 214 and 224 are preferably provided as haake bolts or rivets to fasten the first end of the upper spring 110 to the first upper bracket 210 and fasten the first end of the lower spring 120 to the first lower bracket 220.

The second rack unit 300 may be divided into: a second upper bracket 310 coupled to a second end of the upper spring 110; a second lower bracket 320 coupled to a second end of the lower spring 120; and a support 330 coupled to the balance shaft base 20 to support the second upper bracket 310 and the second lower bracket 320.

The second upper bracket 310 includes: a third upper plate 311 laterally extending from the upper end of the supporter 330 to contact the upper side surface of the second end of the upper spring 110; and a third lower plate 312 extending from a side surface of the supporter 330 while being spaced apart from the third upper plate 311 below the third upper plate to be in contact with a lower side surface of the second end portion of the upper spring 110.

Similar to the second upper bracket 310, the second lower bracket 320 includes: a fourth upper plate 321 extending from a side surface of the supporter 330 while being spaced apart from the third lower plate 312 below to be in contact with an upper side surface of the second end portion of the lower spring 120; and a fourth lower plate 322 extending from a side surface of the support 330 while being spaced apart from the fourth upper plate 321 below the fourth upper plate to be in contact with a lower side surface of the second end portion of the lower spring 120.

Meanwhile, the supporter 330 is provided at an upper portion of the balance shaft base 20 to be formed in a block shape having a predetermined height, and the supporter 330 and the balance shaft base 20 may be welded together, fastened together by a coupling member such as a bolt, or integrally molded and provided as one body.

Preferably, the second rack unit 300 further includes: a third fixing member 313 configured to sequentially pass through the third upper plate 311, the upper spring 110, and the third lower plate 312 to fix a second end of the upper spring 110 to the second upper bracket 310; and a fourth fixing member 323 configured to sequentially pass through the fourth upper plate 321, the lower spring 120, and the fourth lower plate 322 to fix the second end of the lower spring 120 to the second lower bracket 320.

The third fixing member 313 and the fourth fixing member 323 are preferably provided as haake bolts or rivets.

The position where each of the above-described first, second, third and fourth fixing members 214, 224, 313 and 323 passes through the respective brackets and springs may be, for example, a case where the first fixing member 214 is inwardly spaced a predetermined distance (e.g., 5mm) from the end portions of the first upper plate 211 and the first lower plate 212. In other words, the first upper plate 211 and the first lower plate 212 are respectively brought into close contact with and fixed to the upper side surface and the lower side surface of the upper spring 110 outward from the position through which the first fixing member 214 passes, whereby it is possible to prevent the problem that the upper spring 110 is damaged due to the breakage of the through hole of the upper spring 110 by the first fixing member 214.

Also, the second, third and fourth fixing members 224, 313 and 323 may be formed to have the same structure to prevent the occurrence of cracks at opposite ends of the upper and lower springs 110 and 120.

Meanwhile, the rubber springs 10 may be installed in opposite directions of the balance shaft base 20, i.e., in the front-rear direction of the vehicle, respectively, and an axle may be coupled to a lower end of each rubber spring 10. In this case, each of the upper and lower springs 110 and 120 is provided in pairs. For example, one upper spring 110 may be coupled to the rubber spring 10 installed in the vehicle forward direction based on the balance shaft base 20, and the other upper spring 110 may be coupled to the rubber spring 10 installed in the vehicle reverse direction based on the balance shaft base 20.

Therefore, it is possible to prevent the problem that the vehicle cannot move in the case where the conventional compound spring is damaged in the related art. In contrast, according to the present invention, even if any one of the compound springs 100 is damaged, the vehicle can be driven.

Meanwhile, as shown in fig. 4, in another embodiment of the composite-material type multi-plate spring suspension according to the present invention, the shape of the composite spring 100 may be different from that of the first embodiment.

The compound spring 100 may be divided into: opposite end portions 101 coupled to both the first and second stand units 200 and 300; and an intermediate portion 102 formed between the opposite end portions, wherein the width of the opposite end portions 101 in the vehicle width direction may be formed smaller than the width of the intermediate portion 102 in the vehicle width direction.

This is to compensate for the problem of the decrease in the transverse modulus of elasticity due to the characteristics of the compound spring 100. When the width of the intermediate portion 102 in the vehicle width direction is increased, the resistance to lateral loads and torsional loads generated during turning and rolling of the vehicle body, in which leftward and rightward shaking occurs, is increased.

Meanwhile, the reinforcing fibers 103 are inserted into the composite spring 100, wherein the reinforcing fibers 103 preferably include first fibers 103a arranged substantially perpendicular to the front-rear direction of the vehicle, i.e., the vehicle width direction.

This is because the direction in which the main load is applied to the composite spring 100 is the front-rear direction, and therefore the stiffness in the length direction, i.e., the front-rear direction and the longitudinal direction, can be increased by the first fibers 103 a.

Meanwhile, the lower spring 120 of the composite spring 100 further preferably includes a second fiber 103b arranged to cross the first fiber 103a, in addition to the first fiber 103 a.

This is because when a lateral load and a torsional load are applied, a greater load is applied to the lower spring 120 than the upper spring 110, and thus it is necessary to improve the lateral stiffness of the lower spring 120.

Therefore, the second fibers 103b are arranged on a diagonal line inclined at an angle of, for example, 45 ° with respect to the arrangement direction of the first fibers 103a, whereby the lateral stiffness of the lower spring 120 can be improved.

Although the preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Accordingly, the preferred embodiments of the present invention have been described for illustrative purposes, and should not be construed as limiting. The scope of the invention is defined by the appended claims rather than by the description given above. Furthermore, the present invention is intended to cover not only the exemplary embodiments but also various alternatives, modifications, equivalents and other embodiments which may be included within the spirit and scope of the present invention as defined by the appended claims.