阅读说明：本技术 磨刀器 (Knife sharpener ) 是由 曾凡钢 于 2021-07-23 设计创作，主要内容包括：本发明涉及磨刀装置技术领域,公开了一种磨刀器,包括固定架,其设有用于刀具插入后刀刃伸出的限位插槽；限位机构,其设置于固定架,限位机构在工作时抵接于刀具以对刀具进行限位；以及磨刀机构,固定架的至少一侧设有磨刀机构,磨刀机构包括滑动连接于固定架的滑块和固定于滑块上的磨刀石,磨刀机构可沿刀具的长度方向滑动。这一装置在磨刀过程中对刀具的一侧进行磨削,避免了双面打磨造成的过度的刀刃损耗,有利于将刀片打薄且保持较长时间的锋利度。(The invention relates to the technical field of knife grinding devices, and discloses a knife sharpener, which comprises a fixed frame, a knife blade and a knife blade fixing device, wherein the fixed frame is provided with a limiting slot for the knife blade to extend out after a knife is inserted; the limiting mechanism is arranged on the fixing frame and is abutted against the cutter to limit the cutter during operation; and the sharpening mechanism is arranged on at least one side of the fixing frame and comprises a sliding block connected to the fixing frame in a sliding manner and a sharpening stone fixed on the sliding block, and the sharpening mechanism can slide along the length direction of the cutter. The device grinds one side of the cutter in the sharpening process, avoids excessive cutter edge loss caused by double-side sharpening, and is beneficial to thinning the cutter and keeping the sharpness for a long time.)

1. A sharpener, comprising:

the fixed frame is provided with a limiting slot for the cutter to extend out after the cutter is inserted;

the limiting mechanism is arranged on the fixing frame and is abutted against the cutter to limit the cutter during working; and

the knife sharpening mechanism is arranged on at least one side of the fixing frame and comprises a sliding block and a knife sharpening stone, the sliding block is connected to the sliding block of the fixing frame in a sliding mode, the knife sharpening stone is fixed on the sliding block, and the sliding block can slide along the length direction of the cutter.

2. The sharpener of claim 1 wherein: the limiting mechanism comprises a first limiting component and a second limiting component which are arranged at two ends of the cutter in the length direction, and the first limiting component and the second limiting component are respectively abutted to two ends of the cutter.

3. The sharpener of claim 2, wherein: the second limiting assembly is fixed on the fixing frame, the first limiting assembly is connected to the fixing frame in a sliding mode, and a driving device is arranged on one side of the first limiting assembly to drive the first limiting assembly to move along the length direction of the cutter.

4. The sharpener of any one of claims 2 or 3, wherein: the first limiting assembly and the second limiting assembly respectively comprise a first limiting block and a second limiting block, the first limiting block is horizontally used for limiting the cutter in the horizontal direction, and the second limiting block is used for limiting the cutter in the vertical direction.

5. The sharpener of claim 4, wherein: but be provided with on the first stopper butt in the horizontal V type groove of the cutting edge of cutter, be provided with on the second stopper butt in the vertical V type groove of the terminal surface of cutter.

6. The sharpener of claim 3, wherein: the driving device comprises a knob and a nut, the knob is connected with a screw rod, one end of the screw rod, which is far away from the knob, is connected with the first limiting assembly, the nut is fixed on the fixing frame, the screw rod penetrates through the nut, and threads of the screw rod are matched with internal threads of the nut.

7. The sharpener of claim 1 wherein: the side of mount has seted up the spout, be equipped with on the slider with spout complex first pulley, it is connected with the whetstone seat to rotate on the slider, whetstone detachably is fixed in the whetstone seat.

8. The sharpener of claim 7, wherein: be provided with solid fixed ring on the slider, the whetstone seat is close to the one end of slider be provided with gu fixed ring complex dead lever, the dead lever is in the whetstone seat rotates the back joint in gu fixed ring.

9. The sharpener of claim 7, wherein: the whetstone seat is connected with the sliding block through a rotating shaft in a rotating mode, a torsion spring is arranged on the rotating shaft, and the torsion spring is far away from one end of the rotating shaft and abuts against the whetstone seat.

10. The sharpener of any one of claims 7-9, wherein: the two sides of the fixing frame are respectively provided with the sharpening mechanisms, and the two side faces of the fixing frame are respectively provided with two sliding grooves to match with the sharpening mechanisms.

Technical Field

The invention relates to the technical field of knife sharpeners, in particular to a knife sharpener.

Background

The knife sharpener often said today is a scientific, practical, efficient and convenient knife sharpener. The name of the knife sharpener is a general name of the appliance for sharpening the knife, which comprises the following components: knife grinding rod, knife grinding stone and knife sharpener. At present, sharpeners can be divided into two types, namely electric sharpeners and manual sharpeners according to the using mode: electric knife sharpener and manual knife sharpener, electric knife sharpener is the utensil that realizes the sharpedge grinding with the rotation of electric drive motor, but electric knife sharpener in the use, can lose a large amount of materials, is unsuitable for polishing the blade thin to the cost is higher. The manual knife sharpener is manually finished, but when the manual knife sharpener is used, double-sided grinding is generally adopted, the knife edge is easily damaged, the sharpness retention of the knife edge is short, and the manual knife sharpener is not suitable for grinding the blade to be thin.

Disclosure of Invention

The purpose of the invention is: the utility model provides a sharpener, its grind one side of cutter at the in-process of whetting a knife, avoided two-sided excessive cutting edge loss that causes of polishing, be favorable to thinning the blade and keep the sharpness of longer time.

In order to achieve the above object, the present invention provides a knife sharpener comprising:

the fixed frame is provided with a limiting slot for the cutter to extend out after the cutter is inserted;

the limiting mechanism is arranged on the fixing frame and is abutted against the cutter to limit the cutter during working; and

the knife sharpening mechanism is arranged on at least one side of the fixing frame and comprises a sliding block and a knife sharpening stone, the sliding block is connected to the sliding block of the fixing frame in a sliding mode, the knife sharpening stone is fixed on the sliding block, and the sliding block can slide along the length direction of the cutter.

Compared with the prior art, the knife sharpener provided by the embodiment of the invention has the beneficial effects that: be provided with spacing slot on the mount, the cutter passes through spacing slot and gets into in the mount and stretches out by the opposite side of mount, is fixed in the mount through stop gear, sets up in the mount wherein the mechanism of whetting a knife of one side slides along the length direction of cutter, drives the whetstone and whets a knife to one side of cutter, accomplishes the unilateral of whetting a knife to the cutter. The device grinds one side of the cutter in the sharpening process, avoids excessive cutter edge loss caused by double-side sharpening, and is beneficial to thinning the cutter and keeping the sharpness for a long time.

According to the knife sharpener provided by the embodiment of the invention, the limiting block comprises a first limiting component and a second limiting component which are arranged at two ends of the knife in the length direction, and the first limiting component and the second limiting component are respectively abutted against two ends of the knife.

According to the knife sharpener provided by the embodiment of the invention, the second limiting assembly is fixed on the fixed frame, the first limiting assembly is connected to the fixed frame in a sliding manner, and a driving device is arranged on one side of the first limiting assembly to drive the first limiting assembly to move along the length direction of the knife.

According to the knife sharpener provided by the embodiment of the invention, the first limiting assembly and the second limiting assembly respectively comprise a first limiting block and a second limiting block, the first limiting block is horizontally used for limiting the knife in the horizontal direction, and the second limiting block is used for limiting the knife in the vertical direction.

According to the knife sharpener disclosed by the embodiment of the invention, the first limiting block is provided with a horizontal V-shaped groove which can be abutted against the cutting edge of the knife, and the second limiting block is provided with a vertical V-shaped groove which can be abutted against the end face of the knife.

According to the sharpener provided by the embodiment of the invention, the driving device comprises the knob and the nut, the knob is connected with the screw rod, one end, far away from the knob, of the screw rod is connected with the first limiting assembly, the nut is fixed on the fixing frame, the screw rod penetrates through the nut, and the thread of the screw rod is matched with the internal thread of the nut.

According to the knife sharpener disclosed by the embodiment of the invention, the side surface of the fixing frame is provided with the sliding groove, the sliding block is provided with the first pulley matched with the sliding groove, the sliding block is rotatably connected with the knife sharpening stone seat, and the knife sharpening stone is detachably fixed in the knife sharpening stone seat.

According to the knife sharpener disclosed by the embodiment of the invention, the slide block is provided with the fixing ring, one end of the knife stone seat close to the slide block is provided with the fixing rod matched with the fixing ring, and the fixing rod is clamped in the fixing ring after the knife stone seat rotates.

According to the knife sharpener provided by the embodiment of the invention, the knife stone seat is rotationally connected to the sliding block through the rotating shaft, the rotating shaft is provided with the torsion spring, and one end of the torsion spring, which is far away from the rotating shaft, abuts against the knife stone seat.

According to the sharpener provided by the embodiment of the invention, two sharpening mechanisms are respectively arranged on two sides of the fixing frame, and two sliding grooves are respectively arranged on two side surfaces of the fixing frame so as to be matched with the two sharpening mechanisms.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 is a schematic view of a knife sharpener according to an embodiment of the present invention;

FIG. 2 is an exploded view of the knife sharpener of the present invention;

FIG. 3 is a front view of the knife sharpener of the present invention with the knife attached;

fig. 4 is a side view of a knife sharpener of an embodiment of the present invention with the knife attached.

In the figure, 1, a fixed frame; 11. limiting slots; 12. a handle; 13. a chute; 2. a limiting mechanism; 21. a first limit component; 211. a second pulley; 22. a second limiting component; 23. a drive device; 231. a knob; 232. a nut; 233. a screw; 24. a first stopper; 241. a horizontal V-shaped groove; 25. a second limiting block; 251. a vertical V-shaped groove; 26. pushing and pulling the cap; 3. a knife sharpening mechanism; 31. a slider; 311. a first pulley; 312. a fixing ring; 32. grinding a knife stone; 33. a sharpening stone seat; 332. a rotating shaft; 333. an elastic element; 34. fixing the rod; 4. and (4) a cutter.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

As shown in fig. 1, the knife sharpener of the preferred embodiment of the present invention includes a fixing frame 1, a limiting slot 11 is provided on the fixing frame 1, a knife 4 enters the fixing frame 1 through the limiting slot 11 and extends out from the other side of the fixing frame 1, the fixing frame 1 may be composed of two cover bodies, a gap is provided between the tops of the cover bodies at two sides, the cover bodies at two sides form the limiting slot 11 in the fixing frame 1 after being spliced, the length and width of the limiting slot 11 are greater than those of a general knife 4, so that the knife 4 enters the fixing frame 1 through an entrance 11, and the knife edge portion of the knife 4 extends out of the fixing frame 1, thereby facilitating the polishing of the knife edge portion; it is understood that the inlet 11 may be integrally formed, and is not limited thereto. Further, a handle 12 is arranged on one side of the fixing frame 1, so that the knife sharpener can be conveniently held.

As shown in fig. 1, the knife sharpener of the preferred embodiment of the present invention further includes a limiting mechanism 2, which is disposed on the fixing frame 1, it can be understood that the limiting mechanism 2 can be disposed on both sides of the length direction of the knife 4, and the knife 4 is limited from both sides of the length direction, and the limiting mechanism 2 can also be disposed on one side of the length direction of the knife 4, so that the knife 4 is limited on one side, and the other end of the knife 4 abuts against the fixing frame 1 to be fixed, which is not limited herein. Specifically, the limiting mechanism can be movable or fixed, the movable limiting mechanism moves along the length direction of the cutter 4, and moves in the direction of the cutter 4 after the cutter is inserted into the limiting slot 11 to limit the cutter 4; the fixed limiting mechanism clamps and fixes the cutter 4 through the length matching of the cutter 4, and the limiting effect can be achieved, and the specific expansion is not made here.

As shown in fig. 1, the sharpener of the preferred embodiment of the present invention further includes a sharpening mechanism 3, and at least one side of the fixing frame 1 is provided with the sharpening mechanism 3 to sharpen the side of the cutter 4. Sharpening mechanism 3 includes sliding connection in slider 31 of mount 1 and the whetstone 32 that is fixed in on slider 31, whetstone 32 is located mount 1's export one side at the during operation, the butt is in the cutting edge part of the cutter 4 who stretches out the export, slider 31 can slide along the length direction of cutter 4, drive whetstone 32 and polish along the cutting edge of cutter 4, accomplish the work of polishing of unilateral, the excessive cutting edge loss that has avoided two-sided polishing to cause, be favorable to polishing the blade and keep the sharpness of longer time.

As shown in fig. 1 and 2, in some embodiments of the present invention, the limiting mechanism includes a first limiting component 21 and a second limiting component 22 disposed at two ends of the cutter 4 in the length direction, and the first limiting component 21 and the second limiting component 22 respectively abut against two ends of the cutter 4 to fix the cutter 4 entering the fixing frame 1;

in some embodiments of the present invention, the first limiting component 21 and the second limiting component 22 may be fixed in the fixing frame 1, in which case the first limiting component 21 and the second limiting component 22 are made of elastic material, and the distance between the first limiting component 21 and the second limiting component 22 is matched with the length of the cutter 4, and when the cutter 4 enters the fixing frame 1, the cutter is clamped in the first limiting component 21 and the second limiting component 22.

In other embodiments of the present invention, the first limiting component 21 and the second limiting component 22 may also be both slidably connected to the fixing frame 1 and respectively located at two sides of the length direction of the cutter 4, after the cutter 4 enters the fixing frame 1, the first limiting component 21 and the second limiting component 22 press the cutter 4 from two sides of the length direction of the cutter 4 to limit the cutter 4, so that the cutter 4 is fixed in the fixing frame 1.

In still other embodiments of the present invention, as shown in fig. 1 and 2, the second position-limiting component 22 is fixed to the fixing frame 1, and the first position-limiting component 21 is slidably connected to the fixing frame 1. Further, the second limiting component 22 is fixed on one side of the fixing frame 1 close to the handle 12, the first limiting component 21 is disposed on one end of the fixing frame 1 far from the handle 12, and the fixing frame 1 is provided with a driving device 23 on one side of the first limiting component 21 to drive the first limiting component 21 to move along the length direction of the cutter 4. After the cutter 4 enters the fixed frame 1, one end of the cutter 4 abuts against the fixed second limiting component 22, and at this time, the driving device 23 drives the first limiting component 21 to move towards the cutter 4, so that the first limiting component 21 abuts against one end of the cutter 4, and the cutter 4 is fixed.

In some embodiments of the present invention as shown in fig. 1, 2 and 3, the driving device 23 includes a knob 231 and a nut 232, the knob 231 is connected with a screw 233, an end of the screw 233 away from the knob 231 is connected to the first position-limiting component 21, the nut 232 is fixed to the fixing frame 1, the screw 233 passes through the nut 232, threads of the screw 233 are matched with internal threads of the nut 232, such that when the knob 231 is rotated, the screw 233 can move in a length direction of the tool 4 under guidance of the internal threads, and after the tool 4 enters, the knob 231 is rotated such that the screw 233 pushes the first position-limiting component 21 to move towards the tool 4 until the first position-limiting component 21 abuts against the tool 4; when the sharpening is completed and the cutter 4 needs to leave the fixed frame 1, the knob 231 is rotated in the opposite direction, so that the screw 233 drives the first limiting component 21 to leave the cutter 4, and the fixing of the cutter 4 is released.

In some embodiments of the present invention, each of the first limiting component 21 and the second limiting component 22 includes a first limiting block 24 and a second limiting block 25, the first limiting block 24 is horizontally used for limiting the cutter 4 in the horizontal direction, and the two first limiting blocks 24 on the first limiting component 21 and the second limiting component 22 are distributed along the same straight line, so that the cutter 4 can be abutted to the two first limiting blocks 24 after entering the fixing frame 1; the second limiting block 25 is used for limiting the cutter 4 in the vertical direction, and the two second limiting blocks 25 on the first limiting assembly 21 and the second limiting assembly 22 are arranged oppositely to fix the cutter 4 between the two second limiting blocks 25.

In some embodiments of the invention, as shown in fig. 2, a V-shaped groove is provided in the limiting mechanism 2, and the V-shaped groove is arranged relative to the cutter 4 to limit the cutter 4 when the cutter 4 is installed. The V-shaped groove can guide the cutter 4 entering the fixed frame 1 to reach a position suitable for sharpening, and positions the edge part of the cutter, so that the problems of side inclination or deviation and the like after the cutter 4 enters the fixed frame 1 are prevented. Specifically, the V-shaped groove may be disposed in the entering direction of the cutter 4, may be disposed on the side of the entering direction of the cutter 4, and may be disposed on the side and below the cutter 4 at the same time.

As shown in fig. 1 and 2, in some embodiments of the present invention, the first limiting component 21 and the second limiting component 22 are separately disposed, and include a first limiting block 24 and a second limiting block 25, the first limiting block 24 is provided with a horizontal V-shaped groove 241 capable of abutting against a cutting edge of the cutter 4, the second limiting block 25 is provided with a vertical V-shaped groove 251 capable of abutting against an end surface of the cutter 4, and the cutter 4 is limited in two directions at the same time, so that the cutter 4 is firmly fixed in the fixing frame 1. Specifically. The horizontal V-shaped grooves 241 on the first limiting blocks 24 of the first limiting assembly 21 and the second limiting assembly 22 are the same in height, so that the blade part of the cutter 4 cannot be inclined, and the cutter is convenient to sharpen; the vertical V-shaped grooves 251 on the second limit blocks 25 of the first limit assembly 21 and the second limit assembly 22 are oppositely arranged to fix the cutter 4 in the fixed frame 1.

In some embodiments of the present invention, a push-pull cap 26 is disposed on one side of the first limiting block 24, and after the tool 4 is limited, the push-pull cap 26 is pulled to pull the first limiting block in a direction away from the tool, so that the first limiting block 24 is away from the tool, and interference with a sharpening process of the sharpening mechanism is prevented.

As shown in fig. 1 and fig. 2, in some embodiments of the present invention, a sliding slot 13 is formed on a side surface of the fixing frame 1, a first pulley 311 engaged with the sliding slot 13 is disposed on the sliding block 31, and the sliding slot 13 extends along a length direction of the fixing frame 1, so that the first pulley 311 can slide along the length direction of the fixing frame 1 to drive the knife sharpening mechanism 3 to move along the length direction of the fixing frame 1. The slider 31 is rotatably connected with a whetstone seat 33, and the whetstone 32 is detachably fixed in the whetstone seat 33, so that the whetstone 32 is firmly fixed, and different kinds of whetstones 32 can be replaced when different whetstones are required, such as fine grinding, rough grinding and the like. The rotatably attached sharpening stone seat 33 can be rotated away from the tool 4 when sharpening is not required. In particular, the sliding groove 13 may be provided in a strip shape or an arc shape for adapting to blades of different shapes. Further, two sides of the first limiting component 21 are also provided with second pulleys 211, the second pulleys 211 extend into the sliding groove 13, the first limiting component 21 is connected in the sliding groove 13 in a sliding manner, and the first limiting component 21 is guided; after the first limiting component 21 limits the tool 4, the second pulley 211 can also be used as the end point of the stroke of the knife sharpening mechanism 3 for accurately limiting the stroke of the first pulley 311.

In some embodiments of the present invention, the sharpening surface of the sharpening stone 32 may be configured to be rectangular or spherical, etc. to meet sharpening requirements of different cutters 4, which is not limited herein. The whetstone 32 can also be provided with two side whetstones, namely a fine grinding surface and a rough grinding surface, the whetstone 32 is directly dismounted after the rough grinding is finished, the turning whetstone is remounted to the whetstone seat 33, the fine grinding of the side surface of the cutter 4 can be immediately carried out, and the device is convenient and fast.

As shown in fig. 1 and 2, in some embodiments of the present invention, two sharpening mechanisms 3 are respectively disposed on two sides of the fixing frame 1, a sharpening stone seat 33 rotatably connected to the sliding block 31 is disposed in each sharpening mechanism 3, and two sliding grooves 13 are respectively disposed on two side surfaces of the fixing frame 1 to cooperate with the two sharpening mechanisms 3. When the cutter 4 is fixed in the fixed frame 1, the knife stone seat 33 on one side is turned over to leave the cutter 4, so that the interference on the knife sharpening process on the other side is prevented, the knife stone 32 in the knife stone seat 33 on the other side is kept to be tightly attached to the cutter 4, and the knife stone 32 tightly attached to the cutter 4 sharpens the edge part of the cutter 4; after one side of the knife is sharpened, the sharpening stone seat 33 which is sharpened on one side is turned over and separated from the cutter 4, the sharpening stone seat 33 which is not sharpened on one side is turned over and attached to the non-sharpened side of the cutter 4, and then the knife grinding on the side is carried out. Through twice single-side sharpening of the two side surfaces, the loss of the cutter 4 caused by sharpening the two sides simultaneously is avoided, and the retention time of the sharpness of the cutter 4 is prolonged.

As shown in fig. 1 to 4, in some embodiments of the present invention, a fixing ring 312 is disposed on the sliding block 31, a fixing rod 34 engaged with the fixing ring 312 is disposed at an end of the whetstone holder 33 close to the sliding block 31, and the fixing rod 34 can be snapped into the fixing ring 312 after the whetstone holder 33 is turned over, so as to fix the turned whetstone holder 33 and prevent influence on one-side sharpening.

As shown in fig. 1 to 4, in the sharpener of the embodiment of the present invention, the whetstone seat 33 is rotatably connected to the slider 31 through the rotating shaft 332, the elastic element 333 is disposed in the whetstone seat 33, one end of the elastic element 333 away from the rotating shaft 332 abuts against the whetstone seat 33, and the elastic element 333 applies force to the whetstone seat 33, so that the whetstone 32 in the whetstone seat 33 can be kept to be closely attached to the blade during sharpening, and no force is required to be applied to the blade, thereby ensuring the sharpening quality of the sharpener. Specifically, the elastic element 333 includes a torsion spring, a spring portion of the torsion spring is sleeved on the rotating shaft 332, and extending portions of two sides of the torsion spring abut against an end surface of the whetstone holder 33 facing away from the fixing frame 1.

The working process of the invention is as follows: the fixed frame 1 is provided with a limiting slot 11, the cutter 4 enters the fixed frame 1 through the limiting slot 11, and is fixed in the fixed frame 1 through a first limiting component 21 and a second limiting component 22 in a limiting mechanism 2, the blade part of the cutter 4 extends out of the fixed frame 1, and the sharpening mechanism 3 arranged on one side of the fixed frame 1 slides along the length direction of the cutter 4 to drive a sharpening stone 32 to sharpen one side of the cutter 4, so that the one-side sharpening of the cutter 4 is completed; after sharpening is completed on one side, the sharpening stone seat 33 on the one side is turned over and separated from the cutting edge, the sharpening stone seat 33 on the other side is turned over and falls to the abutting cutting edge, and sharpening is performed on the other side.

To sum up, the embodiment of the invention provides a knife sharpener, which independently grinds two sides of a knife 4 in the process of sharpening the knife, avoids excessive edge loss caused by double-sided sharpening, and is beneficial to thinning the knife and keeping the sharpness for a long time; the structure is simple, the use is convenient, the knife can be easily sharpened without professional sharpening skills, and a better effect can be achieved in a short time; the production and use cost is low, and the safety is high without contacting with a blade and using an electric drive.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.