阅读说明：本技术 一种润滑剂的加注设备及烧结机系统 (Lubricant filling equipment and sintering machine system ) 是由 刘克俭 戴波 邱立运 谭潇玲 于 2021-11-04 设计创作，主要内容包括：本发明公开一种润滑剂的加注设备及烧结机系统,其中,该加注设备用于为沿第一方向运动的待润滑部件添加润滑剂,所述待润滑部件设有接收嘴,在所述待润滑部件的运行面内,与所述第一方向相垂直的方向为第二方向；所述加注设备包括跟随装置、定位装置和加注装置,所述定位装置和所述加注装置均直接或者间接地安装于所述跟随装置,所述加注装置包括加注枪和加注驱动件,所述加注枪安装于所述定位装置,所述定位装置能够对齐所述加注枪和所述接收嘴,所述加注驱动件用于驱使所述加注枪沿所述第二方向进行动作,以与所述接收嘴相对接或者相脱离,所述跟随装置能够沿所述第一方向与所述待润滑部件同步运动。(The invention discloses a lubricant filling device and a sintering machine system, wherein the lubricant filling device is used for adding a lubricant to a part to be lubricated, which moves along a first direction, the part to be lubricated is provided with a receiving nozzle, and the direction perpendicular to the first direction in the running surface of the part to be lubricated is a second direction; the filling device comprises a following device, a positioning device and a filling device, wherein the positioning device and the filling device are directly or indirectly arranged on the following device, the filling device comprises a filling gun and a filling driving part, the filling gun is arranged on the positioning device, the positioning device can align the filling gun and the receiving nozzle, the filling driving part is used for driving the filling gun to move along the second direction so as to be in butt joint with or separated from the receiving nozzle, and the following device can synchronously move with the part to be lubricated along the first direction.)

1. A lubricant filling device for adding lubricant to a part (6) to be lubricated which moves in a first direction, the part (6) to be lubricated being provided with a receiving nozzle (61), in the running surface of the part (6) to be lubricated, a direction perpendicular to the first direction being a second direction, characterized in that the filling device comprises a following device (1), a positioning device (2) and a filling device (3), the positioning device (2) and the filling device (3) both being mounted directly or indirectly to the following device (1), the filling device (3) comprising a filling gun (31) and a filling drive, the filling gun (31) being mounted to the positioning device (2), the positioning device (2) being capable of aligning the filling gun (31) and the receiving nozzle (61), the filling drive being used for driving the filling gun (31) to move in the second direction, for abutment with or disengagement from the receiving mouth (61), the follower device (1) being capable of moving synchronously with the component to be lubricated (6) in the first direction.

2. The lubricant filling device according to claim 1, characterized in that the positioning device (2) comprises a positioning rudder (21) and a positioning driving member, wherein the positioning driving member can drive the positioning rudder (21) to displace in the second direction so that the positioning rudder (21) can move to the front of the part to be lubricated (6) and is jointed with the part to be lubricated (6);

the filling gun (31) and the receiving nozzle (61) are aligned in a state that the positioning rudder (21) is attached to the part (6) to be lubricated.

3. The lubricant filling device according to claim 2, characterized in that the positioning rudder (21) comprises a first positioning beam (211) and a second positioning beam (212) which are arranged at an included angle, the first positioning beam (211) and the second positioning beam (212) are both provided with a roller, and the first positioning beam (211) and the second positioning beam (212) are both attached to the part (6) to be lubricated through the rollers.

4. Lubricant filling apparatus according to claim 3, characterized in that said first positioning beam (211) and said second positioning beam (212) are perpendicular.

5. The lubricant filling apparatus according to claim 2, characterized in that the positioning device (2) further comprises a gun rest (22), the gun rest (22) being used for mounting the filling gun (31).

6. The lubricant filling device according to claim 2, wherein the positioning device (2) further comprises a fixed seat (23), the positioning rudder (21) is mounted on the fixed seat (23) through a connecting beam (24), and the positioning driving member is in transmission connection with the fixed seat (23) and is used for driving the fixed seat (23) to displace along the second direction.

7. The lubricant filling device according to claim 2, characterized in that the follower device (1) further comprises a return drive for driving the follower device (1) into a return position after the lubricant filling is finished and the positioning rudder (21) is disengaged from the part to be lubricated (6).

8. The lubricant filling apparatus according to any one of claims 1 to 7, further comprising a support frame (4), the support frame (4) being provided with a first track (41) extending in the first direction, the following device (1) being capable of running along the first track (41).

9. The lubricant dosing device according to any one of claims 2 to 7, characterized by further comprising detection means (5), upstream of said positioning means (2) in said first direction, for detecting whether said component to be lubricated (6) passes said detection means (5);

the detection device (5) is in signal connection with the positioning driving piece, and when the detection device (5) detects that the part (6) to be lubricated passes through, the positioning driving piece is used for driving the positioning rudder (21) to act.

10. Lubricant filling apparatus according to claim 9, characterized in that said detection device (5) is a travel switch; alternatively, the detection device (5) is a photoelectric detection device.

11. A sintering machine system comprising a pallet equipped with wheels, characterized by further comprising a lubricant filling apparatus according to any one of claims 1 to 10, wherein the part to be lubricated is the wheels.

Technical Field

The invention relates to the technical field of lubricant filling, in particular to lubricant filling equipment and a sintering machine system.

Background

The sintering machine is a device for fusing and agglomerating fine powder and small-particle iron-containing raw materials by adopting a thermal consolidation method, and is one of main devices for producing blast furnace burden in the ferrous metallurgy industry.

Generally, a sintering machine includes a rail and a plurality of trolleys, each equipped with wheels for running on the rail. In order to continuously and stably run the bogie for a long period of time, it is necessary to ensure that the wheels are in a good lubrication state, that is, to replenish each wheel with a lubricant in a timely manner. However, due to the nature of the sintering process, it is not possible to stop the sintering machine for the addition of lubricant to the wheels, and thus it is desirable to complete the addition of lubricant during the operation of the sintering machine so as not to interfere with the continuous operation of the sintering process.

At present, the addition of the lubricant is mainly completed by manpower, and the labor intensity of the manpower is higher. Moreover, the ambient temperature near the sintering machine is close to 100 ℃, the working environment is extremely poor, and manual operation can bring adverse effects to the life health of operators.

Disclosure of Invention

The invention aims to provide lubricant filling equipment and a sintering machine system, wherein the lubricant filling equipment can greatly reduce the labor intensity of workers, can reduce the influence of environmental factors on the life health of the workers and can improve the automation level of the equipment.

In order to solve the technical problem, the invention provides a lubricant filling device, which is used for adding lubricant to a part to be lubricated, which moves along a first direction, wherein the part to be lubricated is provided with a receiving nozzle, and the direction perpendicular to the first direction in the running surface of the part to be lubricated is a second direction; the filling device comprises a following device, a positioning device and a filling device, wherein the positioning device and the filling device are directly or indirectly arranged on the following device, the filling device comprises a filling gun and a filling driving part, the filling gun is arranged on the positioning device, the positioning device can align the filling gun and the receiving nozzle, the filling driving part is used for driving the filling gun to move along the second direction so as to be in butt joint with or separated from the receiving nozzle, and the following device can synchronously move with the part to be lubricated along the first direction.

By adopting the structure, when the lubricating device is used, the filling equipment can automatically align the filling gun and the receiving nozzle by virtue of the positioning device, butt joint of the filling gun and the receiving nozzle is completed under the action of the filling driving part, the following device can synchronously follow the part to be lubricated to act along the first direction in cooperation with the positioning device and the filling device, and non-stop and on-line automatic lubricant filling for the part to be lubricated can be realized.

Compared with the prior art, the filling equipment provided by the invention can greatly reduce the labor intensity of workers, can reduce the influence of environmental factors on the life health of the workers, and can improve the automation level of the equipment.

Optionally, the positioning device includes a positioning rudder and a positioning driving member, and the positioning driving member can drive the positioning rudder to displace along the second direction, so that the positioning rudder can move to the front of the component to be lubricated and attach to the component to be lubricated; and when the positioning rudder is attached to the part to be lubricated, the filling gun is aligned with the receiving nozzle.

Optionally, the location rudder is including being first locating beam and the second locating beam of contained angle setting, first locating beam with the second locating beam all disposes the gyro wheel, first locating beam with the second locating beam all passes through the gyro wheel with treat that lubricated part is laminated mutually.

Optionally, the first positioning beam and the second positioning beam are perpendicular.

Optionally, the positioning device further comprises a gun rack for mounting the filling gun.

Optionally, the positioning device further comprises a fixed seat, the positioning rudder is mounted on the fixed seat through a connecting beam, and the positioning driving member is in transmission connection with the fixed seat and is used for driving the fixed seat to displace along the second direction.

Optionally, the following device further comprises a return driving member, and after the lubricant is filled and the positioning rudder is separated from the component to be lubricated, the return driving member is used for driving the following device to return.

Optionally, the device further comprises a support frame, the support frame is provided with a first rail extending along the first direction, and the following device can run along the first rail.

Optionally, the lubrication device further comprises a detecting device, wherein the detecting device is located upstream of the positioning device in the first direction and is used for detecting whether the component to be lubricated passes through the detecting device; the detection device is further in signal connection with the positioning driving piece, and when the detection device detects that the part to be lubricated passes through, the positioning driving piece is used for driving the positioning rudder to act.

Optionally, the detection device is a travel switch; alternatively, the detection device is a photoelectric detection device.

The invention also provides a sintering machine system which comprises a sintering trolley and the lubricant filling equipment, wherein the sintering trolley is provided with wheels, and the wheels are the parts to be lubricated.

Since the above lubricant filling device has the above technical effects, the sintering machine system having the lubricant filling device also has similar technical effects, and therefore, the details are not repeated herein.

Drawings

FIG. 1 is a schematic structural view of a lubricant filling apparatus provided in the present invention applied to a wheel of a sintering pallet;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a schematic structural diagram of one embodiment of a positioning device;

FIG. 4 is a schematic view of the positioning rudder in a second direction;

FIG. 5 is a schematic structural view of the positioning rudder engaging with a member to be lubricated;

FIG. 6 is a schematic view of the positioning device of FIG. 3 in engagement with a component to be lubricated;

FIG. 7 is a schematic structural diagram of one embodiment of a detection device;

fig. 8 is a schematic structural diagram of another embodiment of the detection device.

The reference numerals in fig. 1-8 are illustrated as follows:

1 following the device;

2, a positioning device, 21 positioning rudders, 211 first positioning beams, 211a first idler wheels, 212 second positioning beams, 212a second idler wheels, 22 gun racks, 23 fixing seats and 24 connecting beams;

3 filling device, 31 filling gun;

4, a support frame, 41 a first rail;

5 detection device, 51 detection rod, 52 emitter, 53 receiver;

6 parts to be lubricated, 61 receiving nozzles;

7 second track.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

As used herein, the term "plurality" refers to an indefinite number of plural, usually more than two; and when the term "plurality" is used to indicate a number of elements, it does not indicate a particular limitation as to the order and/or importance.

The terms "first," "second," and the like, herein are used for convenience in describing two or more structures or components that are identical or similar in structure and/or function and do not denote any particular limitation in order and/or importance.

Referring to fig. 1 to 8, fig. 1 is a schematic structural view illustrating a lubricant filling apparatus applied to a wheel of a sintering pallet, fig. 2 is a front view of fig. 1, fig. 3 is a schematic structural view illustrating an embodiment of a positioning device, fig. 4 is a schematic structural view illustrating a positioning rudder moving in a second direction, fig. 5 is a schematic structural view illustrating the positioning rudder and a member to be lubricated in a fitted state, fig. 6 is a schematic structural view illustrating the positioning device in fig. 3 and the member to be lubricated in a fitted state, fig. 7 is a schematic structural view illustrating an embodiment of a detection device, and fig. 8 is a schematic structural view illustrating another embodiment of the detection device.

As shown in fig. 1 and 2, the present invention provides a lubricant filling apparatus for adding lubricant to a member to be lubricated 6 moving in a first direction, the type of the lubricant is not limited, and there is a specific relationship with the type of the member to be lubricated 6. Taking the sintering machine system as an example, the first direction refers to a running direction of the sintering pallet, that is, an arrangement direction of the second rail 7, wheels of the sintering pallet can run along the second rail 7, and the component 6 to be lubricated may specifically refer to a wheel, on which a receiving nozzle 61 may be provided for guiding the lubricant to guide the lubricant to a portion to be lubricated of the component 6 to be lubricated. In the running surface of the component 6 to be lubricated, the direction perpendicular to the first direction may be referred to as the second direction.

The filling device comprises a following device 1, a positioning device 2 and a filling device 3. The following device 1 is synchronously movable in a first direction with the component 6 to be lubricated, and the positioning device 2 and the filling device 3 are both mounted directly or indirectly to the following device 1, so that the positioning device 2 and the filling device 3 can be moved together with the following device 1 in the first direction. Taking the positioning device 2 as an example, the direct installation here means that no other component is arranged between the positioning device 2 and the following device 1, and the indirect installation means that other component is arranged between the positioning device 2 and the following device 1; for example, the filling device 3 may be directly mounted to the following device 1, and the positioning device 2 may be directly mounted to the filling device 3, so that the positioning device 2 is indirectly mounted to the following device 1.

The filling device 3 comprises a filling gun 31 and a filling driving member, wherein the filling gun 31 is mounted on the positioning device 2, the positioning device 2 can align the filling gun 31 with the receiving nozzle 61, and the filling driving member is used for driving the filling gun 31 to move along the second direction to be in butt joint with or separated from the receiving nozzle 61.

By adopting the structure, when the lubricating device is used, the filling equipment can automatically align the filling gun 31 and the receiving nozzle by virtue of the positioning device 2, butt joint of the filling gun 31 and the receiving nozzle is completed under the action of the filling driving part, the following device 1 can synchronously follow the part to be lubricated 6 to act along the first direction in cooperation with the positioning device 2 and the filling device 3, and non-stop and on-line automatic lubricant filling for the part to be lubricated 6 can be realized.

Compared with the prior art, the filling equipment provided by the invention can greatly reduce the labor intensity of workers, can reduce the influence of environmental factors on the life health of the workers, and can improve the automation level of the equipment.

Here, the embodiment of the present invention does not limit the way in which the positioning device 2 positions the alignment filling gun 31 and the receiving nozzle 61 and the way in which the following device 1 follows the synchronous operation of the component to be lubricated 6, as long as the above-described technical effects can be achieved. For example, the positioning device 2 can position the alignment filling gun 31 and the receiving nozzle 61 by means of a visual detection system, an infrared detection system or the like, and the following device 1 can be equipped with a following drive which can produce the same linear velocity as the component 6 to be lubricated, so that the following device 1 can synchronously follow the displacement of the component 6 to be lubricated.

In particular, in the embodiment of the present invention, the positioning device 2 may include a positioning rudder 21 and a positioning driving member (not shown in the drawings), and the positioning driving member may drive the positioning rudder 21 to displace in the second direction, so that the positioning rudder 21 can move to the front of the component 6 to be lubricated. In this way, during the movement of the component 6 to be lubricated, the positioning rudder 21 can naturally abut against the component 6 to be lubricated, and in the state where the positioning rudder 21 abuts against the component 6 to be lubricated, the filling gun 31 and the receiving nozzle 61 can naturally align.

With the arrangement, only the installation position of the filling gun 31 on the positioning device 2 needs to be controlled, namely the filling gun 31 and the receiving nozzle 61 can be controlled to be aligned when the positioning rudder 21 is jointed with the part 6 to be lubricated, no complicated equipment such as a visual detection part and an infrared detection part needs to be arranged, and the structural form of the positioning device 2 can be relatively simple.

More importantly, after the positioning rudder 21 is attached to the component 6 to be lubricated, the motion of the component 6 to be lubricated generates a driving force on the positioning rudder 21, and the driving force can be finally transmitted to the following device 1 to drive the following device 1 to naturally perform synchronous displacement along with the component 6 to be lubricated. That is, no special follower drive and no complex follower control strategy can be provided, which in turn can simplify the structure of the follower device 1.

The structural style of the positioning rudder 21 can be various as long as the technical effect that the positioning rudder can be attached to the part 6 to be lubricated and the following device 1 is driven to synchronously displace under the driving of the part 6 to be lubricated can be met.

In a specific scheme, as shown in fig. 3, the positioning rudder 21 may include a first positioning beam 211 and a second positioning beam 212 disposed at an included angle, the first positioning beam 211 may be configured with a first roller 211a, the second positioning beam 212 may be configured with a second roller 212a, and the first positioning beam 211 and the second positioning beam 212 may be specifically attached to the component 6 to be lubricated through the first roller 211a and the second roller 212 a. In this way, wear generated during movement of the member to be lubricated 6 and between the first positioning beam 211 and the second positioning beam 212 can be reduced.

The number of the first rollers 211a and the second rollers 212a is not limited herein, and in a specific practice, a person skilled in the art can determine the number according to actual needs as long as the use requirements can be met. In addition, the angle between the first positioning beam 211 and the second positioning beam 212 is not limited in the embodiment of the present invention.

In the embodiment of the drawings, the first and second positioning beams 211 and 212 may be perpendicular. With reference to fig. 6, taking a to-be-lubricated member 6 (such as a wheel) with a circular cross section perpendicular to the axial direction as an example, the first positioning beam 211 and the second positioning beam 212 perpendicular to each other may respectively abut on an upper vertex and a left vertex of the to-be-lubricated member 6; in this way, perpendicular lines are respectively made on contact points of the first positioning beam 211 and the second positioning beam 212 with the component 6 to be lubricated, an intersection point of the two perpendicular lines can be on a central axis of the component 6 to be lubricated, and in practical application, the filling gun 31 can be installed at the intersection point, that is, the filling gun 31 can be aligned with the receiving nozzle 61 arranged at the central axis of the component 6 to be lubricated.

In specific practice, the filling gun 31 can have different installation positions according to different structural forms of the positioning rudder 21 and the to-be-lubricated part 6, but only after the positioning rudder 21 and the to-be-lubricated part 6 are in contact with each other, the filling gun 31 can be aligned with the receiving nozzle 61 of the to-be-lubricated part 6.

Further, the positioning device 2 may also include a gun rack 22, the gun rack 22 being used for mounting the filling gun 31. The assembly relationship between the filling gun 31 and the gun rack 22 is specifically as follows: the filling gun 31 can synchronously move along the first direction with the gun frame 22, and simultaneously, the filling gun 31 can move along the second direction relative to the gun frame 22 so that the filling gun 31 is in butt joint with or separated from the receiving nozzle 61, thereby meeting the action requirement of the filling gun 31.

Specifically, the gun rest 22 may be provided with a mounting hole extending in the second direction, and the filling gun 31 may be fitted in the mounting hole and be capable of moving relative to the gun rest 22 in the axial direction of the mounting hole; the gun rack 22 can be provided with a detachable limiting structure to avoid the separation of the filling gun 31 and the gun rack 22 and ensure the reliability of the assembly of the filling gun 31.

As shown in fig. 3, the positioning device 2 may further include a fixing seat 23, the positioning rudder 21 may be mounted on the fixing seat 23 through a connecting beam 24, and the positioning driving member may be in transmission connection with the fixing seat 23 for driving the fixing seat 23 to displace along the second direction; the gun rest 22 may be mounted to the connecting beam 24, and the specific structure of the connecting beam 24 is not limited herein. In practical use, the connecting beam 24 may be directly connected to the positioning driving member in a transmission manner, or the positioning rudder 21 may be connected to the positioning driving member in a transmission manner.

In this context, the structural forms of the filling driving element and the positioning driving element are not limited, as long as the filling driving element and the positioning driving element can realize the motion forms required by the filling gun 31 and the positioning rudder 21, that is, the filling driving element and the positioning driving element can realize linear displacement. Therefore, the driving element which can directly output linear displacement such as a linear air cylinder, a hydraulic oil cylinder and the like can be adopted for filling the driving element and positioning the driving element; or, the filling driving member and the positioning driving member may further be configured with driving elements capable of directly outputting rotational displacement, such as a motor and a rotary cylinder, and at this time, the filling driving member and the positioning driving member may further be configured with displacement conversion structures in the form of a rack-and-pinion structure, a screw structure, and the like, so as to convert the rotational displacement directly output by the driving elements into the required linear displacement.

The following embodiments of the present invention will further describe the movement process of the positioning device 2 and the filling device 3 with reference to fig. 4 and 5. Firstly, under the action of the positioning driving piece, the positioning rudder 21 can be V₁Until it moves in front of the part 6 to be lubricated; the moving component 6 to be lubricated can then come into contact with the positioning rudder 21 and drive the positioning device 2 together with the follower device 1 at V₂Is synchronously displaced along a first direction; the filling drive can then actuate the filling gun 31 to displace into abutment with the aligned receiving mouth 61 and fill the part 6 to be lubricated with lubricating oil; after the lubricating oil is filled, the filling driving part can drive the filling gun 31 to be separated from the receiving nozzle 61, the positioning driving part can drive the positioning rudder 21 to be separated from the part to be lubricated 6, and at the moment, the following device 1 does not follow the part to be lubricated 6 to perform synchronous motion.

Further, the following device 1 may further include a return driving member, and after the lubricant is filled and the positioning rudder 21 is separated from the component 6 to be lubricated, the return driving member is used for driving the following device 1 to return. In this way, the travel of the follower device 1 can be controlled within a certain range to avoid the filling apparatus provided by the present invention taking up too much space.

The return drive member may be configured as described above with reference to the filling drive member and the positioning drive member. Or, the return driving member may also be a component having a certain elasticity, such as a return spring, and when the following device 1 is displaced synchronously with the component 6 to be lubricated, the return driving member may accumulate elastic potential energy, and after the positioning rudder 21 is separated from the component 6 to be lubricated, the elastic potential energy of the return driving member may be released, and the following device 1 may also be driven to return.

Further, the lubricant filling device can further comprise a supporting frame 4, the supporting frame 4 can be provided with a first track 41 extending along a first direction, the following device 1 can run along the first track 41, the running direction of the following device 1 and the distance between the following device 1 and the part to be lubricated 6 in a second direction are guaranteed, and then the stability in the lubricant filling process can be guaranteed.

Here, the embodiment of the present invention does not limit the structural form of the first track 41, and in particular practice, a person skilled in the art may determine the structural form of the following device 1 according to various factors, so long as the above-mentioned use effect can be satisfied. In the embodiment of the drawings, as shown in fig. 1 and 2, the first rail 41 may be a channel, and the follower device 1 may be provided with wheels, and the wheels may run in the channel.

Further, the filling apparatus provided by the present invention may further include a detecting device 5, and in the first direction, the detecting device 5 may be located upstream of the positioning device 2, and is configured to detect whether the component to be lubricated 6 passes through the detecting device 5; the detection device 5 can also be in signal connection with a positioning driving piece, and when the detection device 5 detects that the component 6 to be lubricated passes through, the positioning driving piece can be used for driving the positioning rudder 21 to act, so that the positioning rudder 21 can move ahead of the component 6 to be lubricated in advance to wait.

The detection device 5 may be a travel switch. As shown in fig. 7, it may include a detection rod 51 rotatably disposed, and when the member to be lubricated 6 passes through, the detection rod 51 may contact the member to be lubricated 6 and can rotate by a specific angle θ under the action of the member to be lubricated 6, and at this time, the detection device 5 may send a signal to the positioning driving member; after the member to be lubricated 6 is away from the detection rod 51, the detection rod 51 can be returned to the original position.

Alternatively, the detection device 5 may be a photodetection device. As shown in fig. 8, it may include an emitter 52 and a receiver 53, and when the component 6 to be lubricated does not arrive, the light emitted from the emitter 52 may be received by the receiver 53; the detection device 5 can send a signal to the positioning drive when the part 6 to be lubricated has passed through it, which can block part or all of the light, so that the amount of light received by the receiver 53 can be reduced or it is not possible to receive light.

It should be emphasized that although the design of the filling device provided by the present invention is intended to address the problem of difficulty in filling lubricant to the wheels of a pallet in a sintering machine system, it is obvious that the application of the filling device provided by the present invention is not limited to sintering machine systems, that is, the application field is not really a limitation on the scope of the implementation of the filling device provided by the present invention, and the filling device can be applied to other similar scenes.

The invention also provides a sintering machine system which comprises the sintering trolley, wherein the sintering trolley is provided with a plurality of wheels. In contrast to the prior art, the sintering machine system according to the present invention is further provided with a lubricant filling device according to each of the above embodiments for lubricating the wheels.

Since the above lubricant filling device has the above technical effects, the sintering machine system having the lubricant filling device also has similar technical effects, and therefore, the details are not repeated herein.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.