Grinding tools

Abstract

This invention relates to a grinding tool, comprising a housing and a mesh cover assembly mounted on the housing. The mesh cover assembly includes a mesh cover fixed to the housing and a first filter screen connected to the mesh cover. The first filter screen has a plurality of first filter holes. The mesh cover assembly also includes a second filter screen that cooperates with the first filter screen and an operating mechanism for driving the second filter screen to move. The second filter screen has a plurality of second filter holes corresponding to the first filter holes. The second filter holes have a first position that does not block the first filter holes and a second position that blocks the first filter holes with the maximum area. The operating mechanism controls the movement of the second filter holes between the first position and the second position.

Description

Technical Field

[0001] This invention relates to the field of power tool technology, and in particular to a grinding tool with a mesh cover assembly. Background Technology

[0002] Grinding tools are a type of power tool driven by an electric motor to perform grinding and cutting operations on workpieces. The high-speed operation of the motor generates a significant amount of heat, while the machining of the workpiece by the output attachment produces a large amount of dust. Therefore, grinding tools must possess both excellent heat dissipation and dustproof performance. However, due to differences in the working environment, the requirements for heat dissipation and dustproof performance of grinding tools also change: in environments with less dust and higher workloads, the tool requires greater heat dissipation; in environments with more dust and lower workloads, the tool requires greater dustproof performance; and in environments with both more dust and higher workloads, the tool should meet both heat dissipation and dustproof requirements.

[0003] Currently, the conventional method for cooling grinding tools is to create air inlets and outlets on the casing, using a fan to draw in cooling air to remove the heat generated by the motor. Furthermore, a filter is installed at the air inlet to trap dust in the cooling air. However, the motor speed and ventilation area of ​​grinding tools are generally constant, meaning the airflow cannot be varied. Therefore, existing grinding tools are only suitable for single-condition operation and cannot be used for multi-condition work, resulting in a poor user experience.

[0004] Therefore, it is determined that it is necessary to provide a new type of grinding tool to overcome the shortcomings of the prior art. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a grinding tool with a mesh cover assembly, which has the advantages of wide applicability, easy operation, precise transmission and good user experience.

[0006] The present invention solves the problems of the prior art by adopting the following technical solution: a grinding tool, including a housing and a mesh cover assembly installed on the housing, the mesh cover assembly including a mesh cover fixed to the housing and a first filter screen connected to the mesh cover, the first filter screen having a plurality of first filter holes, the mesh cover assembly including a second filter screen cooperating with the first filter screen and an operating mechanism for driving the second filter screen to move, the second filter screen having a plurality of second filter holes corresponding to the first filter holes, the second filter holes having a first position that does not block the first filter holes and a second position that blocks the first filter holes with the maximum area, the operating mechanism controlling the movement of the second filter holes between the first position and the second position.

[0007] A further improvement is as follows: The second filter screen includes a driven member connected to the left end and a receiving tooth disposed at the lower end of the driven member. The operating mechanism is provided with a drive wheel. The drive wheel has a circular turntable and drive teeth spaced apart on the outer periphery of the turntable. The drive teeth mesh with the receiving teeth to drive the second filter screen to move.

[0008] A further improvement is as follows: the operating mechanism has a hollow limiting plate and a rod passing through the limiting plate. The limiting plate has a groove on its inner wall, and the rod has a protrusion on its outer periphery. The protrusion cooperates with the groove.

[0009] A further improvement is as follows: the operating mechanism has a knob installed at the front end of the rod, the drive wheel is located at the rear end of the rod, and the knob drives the rod and the drive wheel to rotate as a whole.

[0010] A further improvement is as follows: the front end of the knob is provided with a gear dial, the gear dial has a stop gear and a start gear, the stop gear and the start gear are spaced apart, and the number of stop gears is equal to the number of start gears.

[0011] A further improvement is that the product of the number n of the stop position or the start position and the tooth pitch L of the two adjacent receiving teeth is equal to the center distance d of the two adjacent second filter holes.

[0012] A further improvement is proposed: the mesh cover has a through-hole in the middle, and the limiting plate is installed in the middle hole.

[0013] A further improvement is that the drive wheel has an outer circumference, the diameter of which is smaller than the diameter of the central hole.

[0014] A further improvement is as follows: the second filter screen has a second mesh body, and the mesh cover is provided with a first track for receiving the second mesh body and a second track for receiving the rack, the first track being connected to the second track.

[0015] A further improvement is that the second track at least partially overlaps with the intermediate hole.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the movement distance of the second filter hole between the first and second positions can be controlled by rotating the operating mechanism, thereby changing the ventilation area on one side of the machine and the flow rate of the intake cooling air. This allows the machine to flexibly adjust its dustproof and heat dissipation performance to meet the needs of multi-condition operation. Specifically:

[0017] 1. Without changing the original structure of the machine, only a central hole and track need to be set on the mesh cover to realize the installation of the operating mechanism and the second filter screen. The structure is ingenious and the layout is compact.

[0018] 2. In the operating mechanism, a protrusion is provided on the rod to cooperate with the groove on the limiting plate, which is beneficial to the positioning of the second filter hole during operation. On this basis, the movement of the second filter hole is driven by the intermittent cooperation between the drive tooth and the receiving tooth, ensuring the accuracy of transmission.

[0019] 3. A gear selector dial is machined on the knob, allowing for clear control of the movement distance of the second filter hole during operation, resulting in a better user experience. Attached Figure Description

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0021] Figure 1 This is a perspective view of a grinding tool according to a preferred embodiment of the present invention;

[0022] Figure 2 yes Figure 1 A cross-sectional view of the grinding tool shown;

[0023] Figure 3 yes Figure 1 A schematic diagram of the mesh cover assembly in the grinding tool shown;

[0024] Figure 4 yes Figure 3 A schematic diagram of the mesh cover in the mesh cover assembly shown;

[0025] Figure 5 yes Figure 4 An enlarged view of part A of the mesh cover shown;

[0026] Figure 6 yes Figure 3 An exploded view of the operating mechanism in the mesh enclosure assembly shown.

[0027] Figure 7 This is a schematic diagram showing the interaction between the operating mechanism and the second filter.

[0028] Figure 8 This is a schematic diagram showing the operating mechanism and the second filter in the first position;

[0029] Figure 9 yes Figure 8 A schematic diagram from another perspective when the operating mechanism and the second filter are in the first position;

[0030] Figure 10 This is a schematic diagram showing the operating mechanism and the second filter in the second position;

[0031] Figure 11 yes Figure 10 A schematic diagram from another perspective when the operating mechanism and the second filter are in the second position;

[0032] Figure 12 It is a graph showing the change in the single-sided ventilation area of ​​the grinding tool and the moving distance of the second filter hole;

[0033] Figure 13 It is a graph showing the change in airflow rate of the grinding tool and the moving distance of the second filter orifice. Detailed Implementation

[0034] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," and "rear" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0035] Please refer to Figures 1 to 2 As shown, an embodiment of the present invention relates to a grinding tool 100, which may be an angle grinder, a polishing machine, etc., and preferably an angle grinder is used as an example. The angle grinder 100 includes a housing 1, a mesh cover assembly 2 mounted on the housing 1, a motor assembly 3 housed in the housing 1, a control assembly 4 driving the motor assembly 3, and an output assembly 5 driven by the motor assembly 3.

[0036] The housing 1 includes: a main housing 11, which is cylindrical and houses a motor assembly 3; a secondary housing 12, which is divided into a cover 121 and a handle 122. Air inlets 123 are provided on the front and rear sides of the cover 121, and a mesh cover assembly 2 is installed at the air inlet 123. The handle 122 is located at the right end of the cover 121, and the two are integrally formed; and a head shell 13, which has an air outlet 131 on its surface.

[0037] The motor assembly 3 is used to provide power for the angle grinder 100 to operate. It includes a stator 31 and a rotor 32. The stator 31 is held in place by the inner wall of the main housing 11 and fixed by screws. The rotor 32 is installed inside the stator 31 and a rotating shaft 33 is formed at the center of the rotor 32. The left and right ends of the rotating shaft 33 are positioned by bearings. A fan 34 and an air guide shroud 35 are also installed at the left end of the rotating shaft 33. When the rotating shaft 33 rotates, the fan 34 rotates and draws in cooling air from outside the angle grinder 100 to dissipate heat from the motor assembly 3. The cooling air then flows out from the air outlet 131 through the air guide shroud 35.

[0038] The function of the control component 4 is to transmit current to the motor assembly 3 and start and stop the motor assembly 3. It includes a trigger 41 located on the handle 122 and a controller 42 installed inside the cover 121: the trigger 41 is configured to be partially exposed on the handle 122 so that the user can hold and press it to control the input of current; the controller 42 is used to receive current signals and drive the operation of the motor assembly 3.

[0039] The output component 5 uses the power generated by the motor component 3 to process the workpiece. Specifically, a first bevel gear 51 is installed on the left side of the fan 34. The first bevel gear 51 rotates synchronously with the rotating shaft 33. Correspondingly, a second bevel gear 52 is provided in the head shell 13 to mesh with the first bevel gear 51. Furthermore, an output shaft 53 is fixed inside the second bevel gear 52. Under the action of the first bevel gear 51, the second bevel gear 52 and the output shaft 53 cause the top tool 54 at the lower end of the output shaft 53 to perform grinding operations.

[0040] Please see Figures 3 to 7 As shown, the mesh cover assembly 2 is used to block the dust generated during the operation of the angle grinder 100 and to allow external airflow to enter. It mainly includes a mesh cover 21, a first filter 23 fixed to the mesh cover 21, a second filter 24 movable relative to the first filter 23, and an operating mechanism 22 for controlling the movement of the second filter 24.

[0041] The mesh cover 21 covers the surface of the air inlet 123 and has a frame 211 with the same outline as the air inlet 123. A support column 212 protrudes from the rear surface of the frame 211, and the mesh cover 21 is fixed to the air inlet 123 by the support column 212. The edge of the rear surface of the frame 211 is processed with a track 213 for the second filter 24 to slide. The track 213 includes a first track 213a and a second track 213b communicating with the first track 213a. The second track 213b is a long and narrow rectangle. A central hole 214 passes through the right end of the frame 211. The central hole 214 at least partially coincides with the second track 213b.

[0042] The operating mechanism 22 is used to control the left and right movement of the second filter screen 24, and includes a rod 221, a knob 222 and a drive wheel 223 respectively installed at both ends of the rod 221, and a limiting plate 224 sleeved on the rod 221.

[0043] The rod 221 is a slender cylinder, and four protrusions 221a are arrayed on its surface. A knob 222 is installed at the front end of the rod 221. A gear shift disc 222a is machined on the front end of the knob 222. The gear shift disc 222a is shaped like a dart, and its surface has a stop position 222b and a start position 222c. Here, the stop position 222b is defined as the position where slightly turning the knob 222 will not move the second filter 24, and the start position 222c is the position where slightly turning the knob 222 will move the second filter 24. Specifically, the stop position 222b... The stop position 222b is the outward convex corner of the gear position disk 222a, and the start position 222c is the inward concave corner of the gear position disk 222a. The number of stop positions 222b and start positions 222c are equal. Here, the number of stop positions 222b and start positions 222c is set to n, and n is preferably 4. Specifically, the surface of the stop position 222b is marked with "0", "1", "2", "3" (hereinafter referred to as 0 position, 1 position, 2 position, and 3 position), and the start positions 222c are marked with "0.5", "1.5", "2.5", "3.5" (hereinafter referred to as 0.5 position, 1.5 position, 2.5 position, and 3.5 position).

[0044] The drive wheel 223 is installed at the rear end of the lever 221 and includes a circular turntable 223a and drive teeth 223b arranged in an array on the circumference of the turntable 223a. There are four drive teeth 223b and their surfaces are marked with "A", "B", "C" and "D" (hereinafter referred to as A teeth, B teeth, C teeth and D teeth). The projection of the line connecting A teeth and C teeth on the gear shift dial 222a coincides with the line connecting 0.5 gear and 2.5 gear.

[0045] The limiting plate 224 is circular, and its outer diameter is equal to the inner diameter of the central hole 214. It is installed into the central hole 214 by interference fit, and the limiting plate 224 cannot rotate relative to the central hole 214. The inner wall of the limiting plate 224 is divided into a groove 224a that mates with the protrusion 221a and a smooth section 224b between the grooves 224a. There are four grooves 224a, which are distributed in the vertical and horizontal directions.

[0046] The first filter screen 23 includes a first mesh body 231 adapted to the shape of the frame 211, with a plurality of first filter holes 232 penetrating the first mesh body 231, and the center distance between adjacent first filter holes 232 is equal; the second filter screen 24 has a second mesh body 241 and a plurality of second filter holes 242 penetrating the second mesh body 241, the size and shape of the second mesh body 241 are the same as the first mesh body 231, and the diameter and number of the second filter holes 242 are the same as the first filter holes 232, that is, when the first mesh... When the body 231 overlaps with the second mesh body 241, each first filter hole 232 has a corresponding second filter hole 242 that overlaps with it; further, the second filter screen 24 is integrally connected to the left end of the second mesh body 241 with a follower 243, the follower 243 is preferably a rack, and the lower end of the rack 243 has equidistantly arranged receiving teeth 243a; the second mesh body 241 and the rack 243 are respectively installed on the first track 213a and the second track 213b in a clearance fit manner.

[0047] Furthermore, as the second filter hole 242 moves, it gradually blocks the first filter hole 232. Here, the position where the second filter hole 242 does not block the first filter hole 232 is defined as the first position, and the position where it blocks the first filter hole 232 with the largest area is defined as the second position. That is, when the knob on the operating mechanism 22 rotates one full circle (360°) from the initial position, the second filter hole 242 moves from the first position to the second position. The process of the operating mechanism 22 controlling the movement of the second filter hole 242 will be described next.

[0048] Please see Figures 7 to 11 As shown, in this embodiment, the diameter of the first filter hole 232 and the second filter hole 242 is D, the center distance between adjacent first filter holes 232 or adjacent second filter holes 242 is d, the tooth pitch of adjacent receiving teeth 243a on the rack 243 is L, and the moving distance of the second filter hole 242 is S, where D is 1.5mm, d is 2mm, and L is 0.25mm; Figure 8 and Figure 9In the first position, the second filter hole 242 is in the first position. At this time, the 0 and 2 gears are located in the vertical direction (defined as the upper position for 0 gear and the lower position for 2 gear). The protrusion 221a is engaged in the groove 224a, that is, the direction of the protrusion 221a is consistent with the orientation of the stop gear 222b. The A gear and the D gear are symmetrical about the line connecting the 0 and 2 gears and do not abut against the receiving gear 243a. If the drive gear 223b is to abut against the receiving gear 243a, the knob 222 needs to be rotated. Specifically, the outer circumference 223c formed by the drive gear 223b must have a contact point with the tooth tip of the receiving gear 243a, and the diameter of the outer circumference 223c must be smaller than the diameter of the middle hole 214. In the first position, rotating the knob 222 to the left will rotate the rod 221, and the protrusion 221a on the right side will disengage. Moving away from the right-side groove 224a and along the smooth section 224b, tooth A also rotates counterclockwise with the drive wheel 223. When gear 0.5 is rotated to the upper position, drive tooth 223b has already driven the receiving tooth 243a to move. It is worth noting that drive tooth 223b does not only engage with receiving tooth 243a when gear 0.5 is rotated to the upper position; at this time, drive tooth 223b has already driven receiving tooth 243a to move 0.5 tooth pitches. When gear 1 is rotated to the upper position, receiving tooth 243a moves one tooth pitch, meaning the second filter hole 242 also moves one tooth pitch, or 0.25mm. In other words, when knob 222 is rotated 90 degrees counterclockwise, the second filter hole 242 moves one tooth pitch to the left. Consequently, if gears 1.5 and 2 are rotated to the upper position, the second filter hole 242 moves 1.5 and 2 tooth pitches respectively; and so on. Figure 10 and Figure 11 In the middle, the 3.5 gear has been turned to the upper position. At this time, the second filter hole 242 has moved 4 tooth pitches, which is 1mm, which is half of the center distance d. In this position, the second filter hole 242 covers the first filter hole 232 with the largest area. This position is the second position. Continue to turn the knob 222 to return the 0 gear to the upper position. During this period, the second filter hole 242 will not move again and will still be in the second position. In the above process, the first position and the second position are two relative positions of the second filter hole 242. The operating mechanism 22 does not have a first position and a second position.

[0049] Furthermore, the influence of the moving distance S of the second filter hole 242 on the heat dissipation and dust prevention performance of the angle grinder 100 was investigated. In this embodiment, the single-sided ventilation area P of the angle grinder 100 and the flow rate Q of the intake cooling air were selected for analysis. Please refer to [link to relevant documentation]. Figures 12 to 13As shown, during the movement of the second filter hole 242 from the first position to the second position, the values ​​of the single-sided ventilation area P and the cooling air flow rate Q decrease: when the moving distance S is between 0 and 0.3 mm, P decreases faster and Q decreases slower. If there are certain requirements for dustproof performance and it is desired to maintain good heat dissipation performance, S can be adjusted within this range. When the moving distance S is between 0.3 mm and 0.7 mm, both P and Q decrease faster. If there are further requirements for dustproof performance and it is desired to maintain a certain level of heat dissipation performance, S can be adjusted within this range. When the moving distance S is between 0.7 mm and 1 mm, the decrease of P and Q is extremely slow. At this time, the dustproof performance of the mesh assembly 2 is good. If the working environment of the angle grinder 100 is relatively extreme and the dust content in the air is high, S can be adjusted within this range.

[0050] In this invention, the center distance d between adjacent second filter holes 242, the tooth pitch L between adjacent receiving teeth 243a, and the number n of stop positions 222b (start positions 222c) are not constant. These three factors should satisfy the following relationship: n*L = d. Based on satisfying the above relationship, this invention has many other embodiments.

[0051] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many alternatives to the grinding tool of this invention exist without departing from the principles and scope of the invention. The scope of protection of this invention is defined by the claims.

Claims

1. A grinding tool, comprising a housing and a mesh cover assembly mounted on the housing, the mesh cover assembly comprising a mesh cover fixed to the housing and a first filter screen connected to the mesh cover, the first filter screen having a plurality of first filter holes; characterized in that: The mesh assembly includes a second filter that cooperates with the first filter and an operating mechanism for driving the second filter to move. The second filter has a plurality of second filter holes corresponding to the first filter holes. The second filter holes have a first position that does not obstruct the first filter holes and a second position that obstructs the first filter holes with the largest area. The operating mechanism controls the movement of the second filter holes between the first position and the second position. The operating mechanism includes a knob and drive teeth driven by the knob. The drive teeth are spaced apart. The second filter includes receiving teeth that mesh with the drive teeth. The knob has start and / or stop positions that are spaced apart. The product of the number n of the stop positions or the start positions and the tooth pitch L of two adjacent receiving teeth is equal to the center distance d of two adjacent second filter holes.

2. The grinding tool according to claim 1, characterized in that: The second filter screen includes a driven member connected to the left end, the receiving tooth is located at the lower end of the driven member, the operating mechanism is provided with a drive wheel, the drive wheel has a circular turntable, the drive teeth are spaced apart on the outer periphery of the turntable, and the drive teeth mesh with the receiving tooth to drive the second filter screen to move.

3. The grinding tool according to claim 2, characterized in that: The operating mechanism has a hollow limiting plate and a rod passing through the limiting plate. The limiting plate has a groove on its inner wall, and the rod has a protrusion on its outer periphery. The protrusion cooperates with the groove.

4. The grinding tool according to claim 3, characterized in that: The knob is installed at the front end of the rod, and the drive wheel is located at the rear end of the rod. The knob drives the rod and the drive wheel to rotate as a whole.

5. The grinding tool according to claim 4, characterized in that: The knob has a gear selector at its front end, and the start and stop gears are located on the gear selector. The number of stop gears is equal to the number of start gears.

6. The grinding tool according to claim 3, characterized in that: The mesh cover has a through hole in the middle, and the limiting plate is installed in the through hole.

7. The grinding tool according to claim 6, characterized in that: The drive wheel has an outer circumference, the diameter of which is smaller than the diameter of the central hole.

8. The grinding tool according to claim 7, characterized in that: The second filter screen has a second mesh body, and the mesh cover is provided with a first track for receiving the second mesh body and a second track for receiving the driven member, the first track being in communication with the second track.

9. The grinding tool according to claim 8, characterized in that: The second track at least partially coincides with the intermediate hole.

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