阅读说明：本技术 一种可多档位选择第五轮转速的拖拉机 (Tractor capable of selecting rotating speed of fifth wheel through multiple gears ) 是由 刘恩丰 于 2020-08-17 设计创作，主要内容包括：本发明涉及农机领域,具体的说是一种可多档位选择第五轮转速的拖拉机,拖拉机内设有发动机、离合器、第五轮、五轮变速箱和提升装置。五轮变速箱包括输入轴、倒档中间轴、输出中间轴、后输出轴和前输出轴。输入轴上安装有倒档主动齿轮、高档主动齿轮和低档主动齿轮。倒档中间轴上安装有倒档中间齿轮。后输出轴上安装有变档主动齿轮、倒档从动齿轮、高档从动齿轮和低档从动齿轮。前输出轴上安装有变档从动齿轮,输出中间轴上安装有变档中间齿轮一和变档中间齿轮二,后输出轴前端与所述前输出轴的后端通过第三啮合套连接或断开,变档从动齿轮一侧设有与第三啮合套联动的第四啮合套。本发明操作方便,工作效率高,安全可靠。(The invention relates to the field of agricultural machinery, in particular to a tractor capable of selecting the rotating speed of a fifth wheel in multiple gears. The five-wheel gearbox comprises an input shaft, a reverse intermediate shaft, an output intermediate shaft, a rear output shaft and a front output shaft. The input shaft is provided with a reverse gear driving gear, a high-gear driving gear and a low-gear driving gear. The reverse intermediate shaft is provided with a reverse intermediate gear. And the rear output shaft is provided with a gear-shifting driving gear, a reverse driven gear, a high-grade driven gear and a low-grade driven gear. The front output shaft is provided with a gear shifting driven gear, the output intermediate shaft is provided with a gear shifting intermediate gear I and a gear shifting intermediate gear II, the front end of the rear output shaft is connected or disconnected with the rear end of the front output shaft through a third meshing sleeve, and one side of the gear shifting driven gear is provided with a fourth meshing sleeve which is linked with the third meshing sleeve. The invention has the advantages of convenient operation, high working efficiency, safety and reliability.)

1. The utility model provides a tractor of fifth wheel rotational speed can be selected to many gears, includes the tractor, be equipped with engine, clutch, fifth wheel and hoisting device in the tractor, hoisting device is used for the promotion or the decline of fifth wheel, its characterized in that: the five-wheel gearbox comprises an input shaft, a reverse intermediate shaft, an output intermediate shaft, a rear output shaft and a front output shaft, wherein a reverse driving gear, a high-grade driving gear and a low-grade driving gear are installed on the input shaft, a reverse intermediate gear meshed with the reverse driving gear is installed on the reverse intermediate shaft, a shift driving gear, a reverse driven gear, a high-grade driven gear and a low-grade driven gear are installed on the rear output shaft and respectively meshed with the reverse intermediate gear, the high-grade driving gear and the low-grade driving gear, the shift driving gear is fixedly installed on the rear output shaft, a first meshing sleeve is arranged on one side of the reverse driven gear, a second meshing sleeve is arranged between the high-grade driven gear and the low-grade driven gear, and a shift driven gear is installed on the front output shaft, a first gear shifting intermediate gear and a second gear shifting intermediate gear which are respectively meshed with the gear shifting driving gear and the gear shifting driven gear are arranged on the output intermediate shaft, the front end of the rear output shaft and the rear end of the front output shaft are connected or disconnected through a third meshing sleeve, a fourth meshing sleeve is arranged on one side of the gear shifting driven gear, the third meshing sleeve and the fourth meshing sleeve are mutually linked, when the third meshing sleeve is moved to connect the rear output shaft and the front output shaft, the fourth meshing sleeve is far away from the gear shifting driven gear, when the third meshing sleeve is moved to disconnect the rear output shaft and the front output shaft, the fourth meshing sleeve is close to the gear-shifting driven gear, the rear end of the input shaft is connected to the engine through the clutch, and the front end of the front output shaft is connected with the fifth wheel.

2. The tractor capable of selecting the rotation speed of the fifth wheel through multiple gears as claimed in claim 1, wherein: the fifth wheel is mounted on an axle which is connected to the front output shaft by a universal joint.

3. The tractor capable of selecting the rotation speed of the fifth wheel through multiple gears as claimed in claim 2, wherein: the lifting device is a hydraulic lifting device.

4. A tractor capable of selecting the speed of a fifth wheel from a plurality of gears as defined in claim 3 wherein: the hydraulic lifting device comprises a connecting rod, a lifting arm, an oil cylinder connecting arm, a rotating shaft, a hydraulic oil cylinder and an oil cylinder seat, wherein the hydraulic oil cylinder is fixed on the tractor through the oil cylinder seat, the oil cylinder connecting arm and the lifting arm are rotatably installed on the rotating shaft, the oil cylinder connecting arm is connected to the hydraulic oil cylinder, the lifting arm is hinged to the upper end of the connecting rod, and the lower end of the connecting rod is hinged to the axle.

5. The tractor capable of selecting the rotation speed of the fifth wheel through multiple gears as claimed in claim 1, wherein: the front end of the rear output shaft and the rear end of the front output shaft are respectively provided with a spline hub, when the third meshing sleeve moves backwards to the spline hub at the front end of the rear output shaft, one part of the third meshing sleeve is still meshed with the spline hub at the rear end of the front output shaft, namely, the third meshing sleeve moves backwards to connect the rear output shaft and the front output shaft, when the third meshing sleeve moves forwards to the spline hub at the rear end of the front output shaft, the third meshing sleeve is completely positioned on the spline hub at the rear end of the front output shaft, and the rear output shaft and the front output shaft are disconnected.

6. The tractor capable of selecting the rotation speed of the fifth wheel with multiple gears as claimed in claim 5, wherein: the fourth meshing sleeve is arranged on the rear side of the gear shifting driven gear.

7. The tractor capable of selecting the rotation speed of the fifth wheel through multiple gears as claimed in claim 1, wherein: the front end of the rear output shaft and the rear end of the front output shaft are respectively provided with a spline hub, when the third meshing sleeve moves backwards to the spline hub at the front end of the rear output shaft, the third meshing sleeve is completely positioned on the spline hub at the front end of the rear output shaft, the rear output shaft and the front output shaft are disconnected, when the third meshing sleeve moves forwards to the spline hub at the rear end of the front output shaft, a part of the third meshing sleeve is still meshed with the spline hub at the front end of the rear output shaft, namely, the third meshing sleeve moves forwards to connect the rear output shaft and the front output shaft.

8. The tractor capable of selecting the rotation speed of the fifth wheel with multiple gears as claimed in claim 7, wherein: the fourth meshing sleeve is arranged on the front side of the gear shifting driven gear.

9. A tractor capable of selecting the speed of a fifth wheel through multiple gears according to any one of claims 1 to 8, wherein: the first meshing sleeve, the second meshing sleeve, the third meshing sleeve and the fourth meshing sleeve are respectively provided with a first shifting fork, a second shifting fork, a third shifting fork and a fourth shifting fork.

10. The tractor capable of selecting the rotation speed of the fifth wheel with multiple gears as claimed in claim 9, wherein: a connecting device that the third fork and the fourth fork are to be connected to each other.

Technical Field

The invention relates to the field of agricultural machinery, in particular to a tractor capable of selecting the rotating speed of a fifth wheel in multiple gears.

Background

A tractor is an important agricultural implement, and when a rear-mounted agricultural implement is mounted for operation, it is generally necessary to turn at the ground, but a four-wheel tractor in the prior art has a large turning radius when turning, and thus has low operation efficiency. Aiming at the problems, in the practical work, a plurality of people artificially modify the four-wheel tractor, only a fifth wheel is additionally arranged in the front of the tractor, the fifth wheel is lifted and descended by utilizing a lifting device, and when the fifth wheel is required to turn, the fifth wheel is forced to rotate by depending on the driving force of a rear wheel so as to turn around and turn the tractor. But only rely on the rear wheel to provide power, just make the fifth wheel power less when rotating, the wheel skids easily when soil texture is comparatively soft or ground is comparatively muddy, and turning power is not enough, and efficiency is lower, and the security performance is relatively poor.

Disclosure of Invention

Aiming at the defects, the invention discloses a tractor capable of selecting the rotating speed of a fifth wheel at multiple gears.

The invention relates to a tractor capable of selecting the rotating speed of a fifth wheel at multiple gears, which comprises a tractor, wherein an engine, a clutch, a five-wheel gearbox, a fifth wheel and a lifting device are arranged in the tractor. The five-wheel gearbox comprises an input shaft, a reverse intermediate shaft, an output intermediate shaft, a rear output shaft and a front output shaft. And the input shaft is provided with a reverse gear driving gear, a high-gear driving gear and a low-gear driving gear. And the reverse intermediate shaft is provided with a reverse intermediate gear meshed with the reverse driving gear. The rear output shaft is provided with a gear shifting driving gear, and a reverse gear driven gear, a high gear driven gear and a low gear driven gear which are respectively meshed with the reverse gear intermediate gear, the high gear driving gear and the low gear driving gear, and the gear shifting driving gear is fixedly arranged on the rear output shaft. And a first meshing sleeve is arranged on one side of the reverse driven gear, and a second meshing sleeve is arranged between the high-gear driven gear and the low-gear driven gear. And the front output shaft is provided with a gear-shifting driven gear. And a first gear shifting intermediate gear and a second gear shifting intermediate gear which are respectively meshed with the gear shifting driving gear and the gear shifting driven gear are arranged on the output intermediate shaft. The front end of the rear output shaft and the rear end of the front output shaft are connected or disconnected through a third meshing sleeve, and a fourth meshing sleeve is arranged on one side of the gear shifting driven gear. The third meshing sleeve and the fourth meshing sleeve are mutually linked, and when the third meshing sleeve is moved to connect the rear output shaft and the front output shaft, the fourth meshing sleeve is far away from the gear shifting driven gear; when the third meshing sleeve is moved to disconnect the rear output shaft from the front output shaft, the fourth meshing sleeve is close to the gear shifting driven gear. The rear end of the input shaft is connected to the engine through the clutch, the front end of the front output shaft is connected with the fifth wheel, and the lifting device is used for lifting or descending the fifth wheel.

Preferably, the fifth wheel is mounted on an axle which is connected to the front output shaft by a universal joint.

Preferably, the lifting device is a hydraulic lifting device.

Preferably, the hydraulic lifting device comprises a connecting rod, a lifting arm, an oil cylinder connecting arm, a rotating shaft, a hydraulic oil cylinder and an oil cylinder seat. The hydraulic oil cylinder is fixed on a tractor through the oil cylinder seat, the oil cylinder connecting arm and the lifting arm are rotatably arranged on the rotating shaft, the oil cylinder connecting arm is connected on the hydraulic oil cylinder, the lifting arm is hinged with the upper end of the connecting rod, and the lower end of the connecting rod is hinged on the axle.

Preferably, a spline hub is mounted to the front end of the rear output shaft and the rear end of the front output shaft, respectively. When the third meshing sleeve moves backwards to the spline hub at the front end of the rear output shaft, one part of the third meshing sleeve is still meshed with the spline hub at the rear end of the front output shaft, namely, the third meshing sleeve connects the rear output shaft with the front output shaft when moving backwards; when the third meshing sleeve moves forwards to the spline hub at the rear end of the front output shaft, the third meshing sleeve is completely positioned on the spline hub at the rear end of the front output shaft, and the rear output shaft and the front output shaft are disconnected.

Preferably, the fourth sleeve is installed at a rear side of the shift driven gear.

Preferably, a spline hub is mounted to the front end of the rear output shaft and the rear end of the front output shaft, respectively. When the third meshing sleeve moves backwards to the spline hub at the front end of the rear output shaft, the third meshing sleeve is completely positioned on the spline hub at the front end of the rear output shaft, and the rear output shaft and the front output shaft are disconnected; when the third meshing sleeve moves forwards to the spline hub at the rear end of the front output shaft, one part of the third meshing sleeve is still meshed with the spline hub at the front end of the rear output shaft, namely, the third meshing sleeve moves forwards to connect the rear output shaft and the front output shaft.

Preferably, the fourth sleeve is installed at a front side of the shift driven gear.

Preferably, the first engaging sleeve, the second engaging sleeve, the third engaging sleeve and the fourth engaging sleeve are respectively provided with a first shifting fork, a second shifting fork, a third shifting fork and a fourth shifting fork.

Preferably, a connecting device that the third fork and the fourth fork are connected to each other.

The invention has the beneficial effects that: the tractor is provided with the five-wheel gearbox for providing power for the fifth wheel and controlling the rotation of the fifth wheel, so that the tractor can have stronger power when turning, and the tractor can easily realize in-situ turning or straight-going operation by combining the lifting device to lift or lower the fifth wheel, and is convenient to operate, high in working efficiency, safe and reliable. The fifth wheel can output four forward gears of a first gear, a second gear, a third gear and a fourth gear and two reverse gears of a first reverse gear and a second reverse gear, namely six different gears, and can meet the requirements of the fifth wheel of the tractor on different gears during turning.

Drawings

The invention will be further described with reference to the accompanying drawings, which are simplified schematic drawings and illustrate only the basic structure of the invention in a schematic manner and do not constitute a limitation on the invention:

FIG. 1 is a schematic structural diagram of a first embodiment of the present invention;

FIG. 2 is a top plan view of the fifth wheel transmission portion of FIG. 1;

FIG. 3 is a schematic structural view of a fifth speed transmission case portion in a second embodiment of the present invention;

in the figure: 101. an input shaft 111, a reverse gear driving gear 112, a high-gear driving gear 113 and a low-gear driving gear; 102. reverse intermediate shaft, 121, reverse intermediate gear; 103. a rear output shaft 131, a reverse driven gear 132, a high-grade driven gear 133, a low-grade driven gear 134, a first meshing sleeve 135, a second meshing sleeve 136, a first shifting fork 137, a second shifting fork 138 and a gear shifting driving gear; 104. a front output shaft 141, a gear-shifting driven gear 142, a third meshing sleeve 143, a fourth meshing sleeve 144, a third shifting fork 145, a fourth shifting fork 146 and a spline hub; 105. an output intermediate shaft 151, a first gear shifting intermediate gear 152 and a second gear shifting intermediate gear; 106. a fifth wheel; 171. the connecting rod 172, the lifting arm 173, the oil cylinder connecting arm 174, the rotating shaft 175, the hydraulic oil cylinder 176 and the oil cylinder seat; 108. an axle; 109. a universal joint.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure, as the terms used are used to describe particular embodiments only, and are not intended to limit the exemplary embodiments based on the disclosure.

The first embodiment:

fig. 1 and 2 show that the tractor capable of selecting the rotating speed of the fifth wheel 106 in multiple gears comprises a tractor, wherein an engine, a clutch, a five-wheel gearbox, the fifth wheel 106 and a lifting device are arranged in the tractor.

The five-wheel gearbox comprises an input shaft 101, a reverse intermediate shaft 102, an output intermediate shaft 105, a rear output shaft 103 and a front output shaft 104. The input shaft 101 is provided with a reverse gear driving gear 111, a high gear driving gear 112 and a low gear driving gear 113. The reverse intermediate gear 121 engaged with the reverse driving gear 111 is mounted on the reverse intermediate shaft 102. The rear output shaft 103 is provided with a shift driving gear 138, and a reverse driven gear 131, a high driven gear 132 and a low driven gear 133 which are respectively engaged with the reverse intermediate gear 121, the high driving gear 112 and the low driving gear 113, and the shift driving gear 138 is fixedly mounted on the rear output shaft 103. A first engaging sleeve 134 is disposed on one side of the reverse driven gear 131, and only a second engaging sleeve 135 is disposed between the high-range driven gear 132 and the low-range driven gear 133. The first engaging sleeve 134 and the second engaging sleeve 135 are respectively provided with a first shifting fork 136 and a second shifting fork 137 for controlling the first engaging sleeve and the second engaging sleeve to move back and forth. The front output shaft 104 is provided with a shift driven gear 141. The output intermediate shaft 105 is provided with a first gear shifting intermediate gear 151 and a second gear shifting intermediate gear 152 which are respectively meshed with the gear shifting driving gear 138 and the gear shifting driven gear 141. The front end of the rear output shaft 103 and the rear end of the front output shaft 104 are connected or disconnected with each other through a third engaging sleeve 142. A fourth engaging sleeve 143 is disposed on one side of the shift driven gear 141. The third engaging sleeve 142 and the fourth engaging sleeve 143 are respectively provided with a third fork 144 and a fourth fork 145 for controlling the forward and backward movement thereof.

The third engaging sleeve 142 and the fourth engaging sleeve 143 are interlocked with each other. When the third engaging sleeve 142 is moved to connect the rear output shaft 103 and the front output shaft 104, the fourth engaging sleeve 143 is moved away from the shift driven gear 141; when the third sleeve 142 is moved to disconnect the rear output shaft 103 from the front output shaft 104, the fourth sleeve 143 approaches the shift driven gear 141.

A spline hub 146 is mounted to the front end of the rear output shaft 103 and the rear end of the front output shaft 104, respectively. When the third engaging sleeve 142 moves backward to the spline hub 146 at the front end of the rear output shaft 103, a part of the third engaging sleeve 142 is still engaged with the spline hub 146 at the rear end of the front output shaft 104, i.e. when the third engaging sleeve 142 moves backward, the rear output shaft 103 is connected with the front output shaft 104; when the third sleeve 142 moves forward to the spline hub 146 at the rear end of the front output shaft 104, it is entirely located on the spline hub 146 at the rear end of the front output shaft 104, and the connection between the rear output shaft 103 and the front output shaft 104 is disconnected. The fourth engaging sleeve 143 is installed at the rear side of the shift driven gear 141, and when the fourth engaging sleeve 143 moves backward, the shift driven gear 141 idles on the front output shaft 104; when the fourth sleeve 143 moves forward, the front output shaft 104 rotates together with the shift driven gear 141.

The rear end of the input shaft 101 is connected to the engine through the clutch. The front end of the front output shaft 104 is connected to the fifth wheel 106, and the connection mode may be: the fifth wheel 106 is mounted on an axle 108, which axle 108 is connected to the front output shaft 104 by a universal joint 109.

The lifting means are used for lifting or lowering the fifth wheel 106. The lifting device is a hydraulic lifting device and comprises a connecting rod 171, a lifting arm 172, an oil cylinder connecting arm 173, a rotating shaft 174, a hydraulic oil cylinder 175 and an oil cylinder seat 176, wherein the hydraulic oil cylinder 175 is fixed on a tractor through the oil cylinder seat 176, the oil cylinder connecting arm 173 and the lifting arm 172 are rotatably arranged on the rotating shaft 174, the oil cylinder connecting arm 173 is connected on the hydraulic oil cylinder 175, the lifting arm 172 is hinged with the upper end of the connecting rod 171, and the lower end of the connecting rod 171 is hinged on the axle 108.

The power of the tractor engine is transmitted to the input shaft 101 of the five-wheel gearbox through the clutch, the high-gear driven gear 132 and the low-gear driven gear 133 are driven to rotate through the rotation of the high-gear driving gear 112 and the low-gear driving gear 113 on the input shaft 101, the rear output shaft 103 is driven to rotate, and the second shifting fork 137 controls the second meshing sleeve 135 to move back and forth to output a low gear or a high gear respectively. The reverse gear driving gear 111 on the input shaft 101 drives the reverse gear intermediate gear 121 to rotate, and further drives the reverse gear driven gear 131 to rotate, and the first shifting fork 136 controls the first meshing sleeve 134 to move back and forth to control the reverse gear to be engaged or disengaged. The shift driving gear 138 is fixedly mounted on the rear output shaft 103 so that it always rotates with the rear output shaft 103, and the shift driving gear transmits the power of the rear output shaft 103 to the shift driven gear 141 through the first shift intermediate gear 151 and the second shift intermediate gear 152.

When the third fork 144 controls the third engaging sleeve 142 to move backward, the front output shaft 104 and the rear output shaft 103 are connected, and at the same time, the fourth fork 145 controls the fourth engaging sleeve 143 to move backward, so that the shift driven gear 141 idles on the front output shaft 104, that is, the front output shaft 104 outputs power transmitted from the rear output shaft 103, and at this time, the first gear, the second gear or the first reverse gear can be output. When the third shifting fork 144 controls the third engaging sleeve 142 to move forward, the front output shaft 104 and the rear output shaft 103 are disconnected, and meanwhile, the fourth shifting fork 145 controls the fourth engaging sleeve 143 to move forward, so that the front output shaft 104 rotates along with the shift driven gear 141, that is, the front output shaft 104 outputs power transmitted by the shift driven gear 141, and at the moment, a third gear, a fourth gear or a second reverse gear can be output. Therefore, the fifth wheel 106 of the present invention can output four forward gears of first gear, second gear, third gear and fourth gear, and two reverse gears of first reverse gear and second reverse gear, which are six different gears, and can meet the requirements of the fifth wheel 106 of the tractor for different gears when turning.

The front end of the front output shaft 104 is connected to an axle 108 on which the fifth wheel 106 is mounted by a universal joint 109, and the fifth wheel 106 can be raised or lowered about the universal joint 109 by a lifting device. When the tractor runs in a straight line, the fifth wheel 106 is lifted by the lifting device, and the operation is carried out by only using the other four wheels of the tractor; when the tractor needs to turn, especially needs to turn on the spot or needs to make a turn with a narrow distance, the fifth wheel 106 is lowered by the lifting device until the front wheel of the tractor is suspended in the air, and then the tractor is turned by matching with different gears of the fifth wheel 106 output by the five-speed gearbox.

Second embodiment:

the second embodiment of the present invention is basically the same as the first embodiment except that the third sleeve 142, the spline hub 146 and the fourth sleeve 143 are mounted in a different position and function. The differences are as follows: as shown in fig. 3, the front end of the rear output shaft 103 and the rear end of the front output shaft 104 are respectively provided with a spline hub 146, when the third engaging sleeve 142 moves backwards to the spline hub 146 at the front end of the rear output shaft 103, it is entirely positioned on the spline hub 146 at the front end of the rear output shaft 103, and the rear output shaft 103 and the front output shaft 104 are disconnected; when the third sleeve 142 moves forward to the spline hub 146 at the rear end of the front output shaft 104, a part of the third sleeve is still engaged with the spline hub 146 at the front end of the rear output shaft 103, i.e. when the third sleeve 142 moves forward, the rear output shaft 103 and the front output shaft 104 are connected. The fourth engaging sleeve 143 is mounted on the front side of the shift driven gear 141, and when the fourth engaging sleeve 143 moves backward, the front output shaft 104 rotates together with the shift driven gear 141; when the fourth sleeve 143 moves forward, the shift driven gear 141 idles on the front output shaft 104.

From the foregoing, the second embodiment differs from the first embodiment only in the shift output mode: when the third fork 144 controls the third engaging sleeve 142 to move forward, the front output shaft 104 and the rear output shaft 103 are in a connected state, and at the same time, the fourth fork 145 controls the fourth engaging sleeve 143 to move forward, so that the shift driven gear 141 idles on the front output shaft 104, that is, the front output shaft 104 outputs power transmitted on the rear output shaft 103, and at this time, first gear, second gear or first reverse gear can be output. When the third shifting fork 144 controls the third engaging sleeve 142 to move backwards, the front output shaft 104 and the rear output shaft 103 are disconnected, and simultaneously the fourth shifting fork 145 controls the fourth engaging sleeve 143 to move backwards, so that the front output shaft 104 rotates along with the shift driven gear 141, that is, the front output shaft 104 outputs power transmitted by the shift driven gear, and at this time, the third gear, the fourth gear or the second reverse gear can be output. Therefore, the fifth wheel 106 of the second embodiment can also output four forward gears of first gear, second gear, third gear and fourth gear and two reverse gears of first reverse gear and second reverse gear, which are six different gears, and can meet the requirements of the fifth wheel 106 of the tractor on different gears when the fifth wheel 106 turns.

In the above two embodiments, when the third fork 144 controls the third engaging sleeve 142 to move backwards, the fourth fork 145 also controls the fourth engaging sleeve 143 to move backwards; when the third fork 144 controls the third engaging sleeve 142 to move forward, the fourth fork 145 also controls the fourth engaging sleeve 143 to move forward. Therefore, for convenience and safety, the third fork 144 and the fourth fork 145 are provided with a connecting device (not shown), and the forward movement or the backward movement of the third engaging sleeve 142 and the fourth engaging sleeve 143 can be simultaneously performed by only moving the third fork 144 or the fourth fork 145 or by only moving the connecting device (not shown). Simple, convenient, safe and reliable.

In the description of the present invention, the terms "front" and "rear" are used with reference to the orientation of the tractor only for the purpose of simplifying the description of the present invention, and should not be construed as limiting the present invention.

In light of the foregoing description of the preferred embodiment of the present invention, it is to be understood that various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.