Grinding tool

Abstract

This invention relates to a grinding tool, comprising a housing, a motor assembly housed within the housing, a control assembly for driving the motor assembly, and a braking assembly for braking the motor assembly. The motor assembly has a central axis extending in a left-right direction along the housing and a drive shaft rotating about the central axis. The control assembly includes a trigger for controlling the motor assembly, the trigger having a first position of closing the motor assembly and a second position of starting the motor assembly. The braking assembly includes a fixed member mounted to the drive shaft, a movable member that brakes the motor assembly by friction with the fixed member, and a linkage member connecting the trigger and the movable member. The movable member has a limit rod protruding from its end face. The linkage member includes a drive end corresponding to the limit rod. The limit rod has a receiving end that cooperates with the drive end. The drive end and the receiving end are in inclined contact. In the first position, the receiving end is spaced apart from the drive end. In the second position, the receiving end abuts against the drive end to drive the movable member to move left and right.

Description

Technical Field

[0001] This invention relates to the field of power tool technology, and in particular to a grinding tool with an improved braking mechanism. Background Technology

[0002] Grinding tools are a type of power tool driven by a motor to perform grinding and cutting operations on workpieces. These output attachments are typically thin, sharp discs such as grinding wheels or cutting wheels. When the user finishes using the grinding tool and immediately releases the switch, the output attachment will continue to rotate for a short period due to the motor's inertia. If the user accidentally touches the output attachment during this time, it could cause injury. Therefore, the motor needs to be quickly braked when the power is turned off.

[0003] Regarding existing technologies for braking grinding tool motors, refer to Chinese Utility Model Patent No. 201721253594.2, published on July 31, 2018. This patent discloses a braking device, including a fixed brake component fixed to a drive shaft, a movable brake component that contacts the fixed brake component and brakes the motor through friction, an elastic component that applies a force to the movable brake component to bring it into contact with the fixed brake component, and a connecting component that applies a force to the movable brake component to separate it from the fixed brake component. This braking device can achieve rapid braking of the motor to a certain extent. However, the connecting component is a flexible steel wire rope. With long-term use of the angle grinder, the connection between the steel wire rope and the trigger and the movable brake component will inevitably loosen, resulting in a weakening or even loss of the braking effect of the device.

[0004] Therefore, it is determined that it is necessary to provide an improved 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 braking component, which has the advantages of compact structure, ingenious layout and good braking effect.

[0006] The present invention solves the problems of the prior art by adopting the following technical solution: a grinding tool, including a housing, a motor assembly housed in the housing, a control assembly for driving the motor assembly, and a braking assembly for braking the motor assembly. The motor assembly has a central axis extending in the left-right direction of the housing and a drive shaft rotating about the central axis. The control assembly includes a trigger for controlling the motor assembly, the trigger having a first position of closing the motor assembly and a second position of starting the motor assembly. The braking assembly includes a fixing member mounted to the drive shaft and a movable member that brakes the motor assembly by friction with the fixing member. The braking assembly has a linkage member connecting the trigger and the movable member. The movable member has a limit rod protruding from its end face. The linkage member includes a drive end corresponding to the limit rod. The limit rod has a receiving end that cooperates with the drive end. The drive end and the receiving end are in inclined contact. In the first position, the receiving end is spaced apart from the drive end. In the second position, the receiving end abuts against the drive end to drive the movable member to move left and right.

[0007] A further improvement is that one of the fixed member and the movable member is equipped with an intermediate member, which abuts against the other to brake the motor assembly.

[0008] A further improvement is as follows: the fixing component includes a first chassis in the shape of a circle, and the intermediate component is installed on the first chassis.

[0009] A further improvement is as follows: the movable component includes a second chassis corresponding to the fixed component, and the intermediate component is mounted on the second chassis.

[0010] A further improvement is as follows: the housing has a accommodating compartment for receiving the braking assembly, the braking assembly has a support mounted on the accommodating compartment, and the movable part is connected to the support via a first elastic element.

[0011] A further improvement is as follows: the limiting rod includes a rod body installed on the second chassis and a rod head extending from the rod body, and the receiving end is disposed on the rod head.

[0012] A further improvement is as follows: the accommodating compartment has a guide hole penetrating the bottom surface and a track communicating with the guide hole; the linkage includes a base plate and a sliding plate extending from the base plate; the trigger is connected to the base plate; and the sliding plate passes through the guide hole and moves in the track.

[0013] A further improvement is as follows: the slide plate includes a straight section extending from the substrate and a ramp section integrally formed with the straight section, and the drive end is integrated into the ramp section.

[0014] The present invention can also solve the problems of the prior art by adopting the following technical solution: a grinding tool, including a housing, a motor assembly housed in the housing, a control assembly for driving the motor assembly, and a braking assembly for braking the motor assembly, the motor assembly having a central axis extending in the left-right direction of the housing and a drive shaft rotating about the central axis, the control assembly including a trigger for controlling the motor assembly, and the braking assembly including a fixing member mounted to the drive shaft and a movable member that brakes the motor assembly by friction with the fixing member; characterized in that: the braking assembly has a linkage member connected between the trigger and the movable member, the trigger driving the linkage member to move up and down to control the movable member to move left and right, and the braking assembly has a second elastic member biasing the linkage member.

[0015] A further improvement is as follows: the housing is provided with a mounting groove, and the second elastic element is fixed to the mounting groove.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Based on the original structure of the housing, only guide holes and rails need to be opened to install the braking components, which can achieve the installation without occupying extra space and has a compact structure;

[0018] 2. The base plate on the linkage is pressed against the trigger, and pulling the trigger will enable the linkage to control the braking component. The layout is ingenious and easy for the user to operate.

[0019] 3. By intermittently contacting the driving end on the linkage and the receiving end on the limit rod, the moving part and the fixed part switch between the contact (braking) and non-contact (non-braking) positions, avoiding the loosening phenomenon that may occur when using flexible steel wire ropes and improving the service life of the braking mechanism.

[0020] 4. A gap is set between the driving end and the receiving end to compensate for the wear thickness caused by long-term braking of the intermediate part, ensuring that the intermediate part can abut against the fixed part when the angle grinder stops, thus ensuring the braking effect. Attached Figure Description

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0022] Figure 1 This is a perspective view of a grinding tool according to a preferred embodiment of the present invention;

[0023] Figure 2 yes Figure 1 A cross-sectional view of the grinding tool shown;

[0024] Figure 3 yes Figure 2The diagram shows the structure of the main housing in the grinding tool.

[0025] Figure 4 yes Figure 3 A schematic diagram of the main casing from another perspective;

[0026] Figure 5 yes Figure 3 An enlarged view of part A in the main housing shown;

[0027] Figure 6 yes Figure 4 An enlarged view of part B in the main housing shown;

[0028] Figure 7 yes Figure 2 An enlarged view of part C of the grinding tool shown;

[0029] Figure 8 yes Figure 7 An exploded view of the braking assembly shown.

[0030] Figure 9 yes Figure 8 An exploded view of the braking assembly shown from another perspective;

[0031] Figure 10 yes Figure 8 A schematic diagram of the linkage component in the braking assembly shown;

[0032] Figure 11 yes Figure 8 The diagram shows the assembly of the linkage and moving parts in the braking assembly.

[0033] Figure 12 yes Figure 1 A schematic diagram of the grinding tool with the trigger in the first position;

[0034] Figure 13 yes Figure 8 The braking assembly shown is in Figure 12 A schematic diagram of the state at the indicated position;

[0035] Figure 14 yes Figure 12 The diagram shows the state when the trigger is in the second position.

[0036] Figure 15 yes Figure 13 The braking assembly shown is in Figure 14 A schematic diagram of the state at the indicated position;

[0037] Figure 16 When the grinding tool is stopped Figure 11 The diagram shows the state of the braking assembly when there is a gap between the driving end and the receiving end.

[0038] Figure 17 When the grinding tool is stopped Figure 11 The diagram shows the state of the braking assembly when the driving end and the receiving end are in contact.

[0039] Figure 18 yes Figure 17 The diagram shows the wear of the intermediate components of the braking assembly after long-term operation.

[0040] Figure 19 yes Figure 18 The braking assembly shown is in Figure 16 The diagram shows the shutdown state when there is a gap between the drive end and the receiving end. Detailed Implementation

[0041] 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.

[0042] Please refer to Figures 1 to 6 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 motor assembly 2 housed inside the housing 1, a control assembly 3 for starting and stopping the motor assembly 2, a braking assembly 4 for braking the motor assembly 2, a transmission assembly 5 driven by the motor assembly 2, and a top assembly 6 driven by the transmission assembly 5 to perform processing operations.

[0043] The housing 1 includes a main housing 11, a rear cover 12, and a gearbox 13. The surface of the main housing 11 is configured as a grip 111 for user operation, and the interior forms a motor chamber 112 for mounting the motor assembly 2. A receiving compartment 14 and a switch compartment 15 are formed at the right end of the main housing 11. The receiving compartment 14 has a guide hole 141 penetrating the lower bottom surface and a mounting groove 142 communicating with the guide hole 141. The guide hole 141 is a flat square hole, and the surface of the mounting groove 142 is semi-circular. A wall hole 145 is opened on the left wall of the receiving compartment 14, and a track 143 is formed on the front and rear walls. The track 143 is defined by a first rib 143a, a second rib 143b, and a stop block 144. The width of the lower part of 3b is greater than the width of the upper part, so the track 143 is divided into a first track cavity 143c and a second track cavity 143d. The width of the second track cavity 143d is greater than the width of the first track cavity 143c. Moreover, the width of the first track cavity 143c is equal to the width of the guide hole 141 and the first track cavity 143c is connected to the guide hole 141. The switch compartment 15 is arranged on the right side of the accommodating compartment 14 and is used to install the control component 3. The rear cover is formed into a cylindrical shape and is detachably connected to the rear end of the main housing 11. Air inlets 121 are opened on the front and rear sides, and a power cord 122 can be plugged into the right end. The transmission component 5 is installed inside the gearbox 13, and an air outlet 131 is opened on the outer surface.

[0044] The motor assembly 2 can be operated by receiving current. It includes a stator 21 and a rotor 22. The stator 21 is fixed by being clamped to the inner wall of the main housing 11. The rotor 22 is inserted inside the stator 21 and is positioned by bearings at both ends of the drive shaft 23. The drive shaft 23 has a central axis 24 and the rotor 22 rotates around the central axis 24. A fan 25 and an air guide shroud 26 are installed on the left side of the drive shaft 23. When the fan 25 rotates, it can draw in outside air from the air inlet 121 to dissipate heat from the motor assembly 2, and then the air flows out from the air outlet 131 after being guided by the air guide shroud 26.

[0045] The control component 3 includes a signal switch 31 installed in the switch compartment 15 and a trigger 32 supported on the rear cover 12. The signal switch 31 is cubic in shape and has a button 311 at its lower end. The trigger 32 includes a rotating plate 322 rotatably connected to the rear cover 12 and a pressing plate 321 integrally formed with the rotating plate 322. The upper end surface of the rotating plate 322 has a first contact 323 and a second contact 324 protruding from it. The first contact 323 cooperates with the braking component 4, and the second contact 324 contacts the button. A locking plate 325 is also installed inside the pressing plate 321. When the locking plate 325 is rotated to the position of abutting against the rear cover 12, the trigger 32 cannot be pressed. When the locking plate 325 is retracted into the pressing plate 321, the trigger 32 can be pressed.

[0046] The transmission assembly 5 includes a first helical gear 51 located at the left end of the drive shaft 23, a second helical gear 52 meshing with the first helical gear 51, and an output shaft 53 installed inside the second helical gear 52. The upper and lower ends of the output shaft 53 are fixed by bearings. The top assembly 6 is installed at the lower end of the output shaft 53. The rotating attachment 61 is fixed by a pressure plate 62 and a locking nut 63. The rotating attachment 61 can be a grinding disc, a saw blade, etc. The outer periphery of the rotating attachment 61 is covered by a protective cover 64, which is installed on the neck 132 of the gearbox 13.

[0047] Please see Figures 7 to 11 As shown, the structure of the braking assembly 4 is described below: The main component of the fixing member 41 is the first chassis 411, which has a threaded hole 414 through it. The fixing member 41 is installed on the drive shaft 23 through the threaded hole 414. The support 45 is installed on the right wall of the accommodating chamber 14 and consists of a base plate 451 and a positioning shaft 452. The base plate 451 can be fixed by screws, and the positioning shaft 452 is integrally cast with the base plate 451. The movable member 42 consists of a second chassis 421 and a movable column 422 protruding from the second chassis 421. The centers of the first chassis 411, the second chassis 421, the movable column 422, and the positioning shaft 452 are all located on the central axis 24, from the left end face of the second chassis 421 to the right end of the movable column 422. The surface extends with mounting holes 423, which are fitted with the positioning shaft 452 with a clearance fit to install the movable part 42. Furthermore, a first elastic element 425 is provided between the second chassis 421 and the base plate 451 to restrict the movement of the movable part 42 on the positioning shaft 452. The inner diameter of the first elastic element 425 must be larger than the outer diameter of the movable column 422. Further, a pair of limiting rods 424 are provided on the right end face of the second chassis 421. The limiting rods 424 are located on both sides of the first elastic element 425. The limiting rods 424 include a rod body 424a and a rod head 424b. The rod body 424a is perpendicular to the second chassis 421, and the rod head 424b is parallel to the second chassis 421. The rod body 424a and the rod head 424b are integrally formed.

[0048] To drive the movable part 42 to move in the left and right direction, a linkage 44 is installed in the track. The linkage 44 includes a base plate 441 and a slide plate 442 extending from the upper surface of the base plate 441. The upper surface of the base plate 441 is connected to the mounting groove 142 through a second elastic member 443, and the lower surface of the base plate 441 abuts against the trigger 32. The slide plate 442 is composed of a straight section 442a, a ramp section 442b, and an end rod 443d. The straight section 442a is connected to the base plate 441 and is adapted to the guide hole 141. The right surface of the ramp section 442b extends at an angle to the straight section 442a, and is defined here as the driving end 442c. The end rod 442b extends at an angle to the straight section 442a. 42d extends from the upper end of the ramp section 442b; when installing the linkage 44 into the receiving chamber 14, the base plate 441 can be connected to the second elastic member 443 first, and then the slide plate 442 is inserted into the guide hole 141. When entering the guide hole 141, the left end face of the end rod 442d should first be attached to the first rib 143a so that it enters the first track cavity 143c. Then, the base plate 441 is pushed up so that the straight section 442a and the ramp section 442b enter the first track cavity 143c and the second track cavity 143d, thus completing the installation of the linkage 44. During this process, the stop block 144 will limit the slide plate 442.

[0049] Since the driving end 442c on the ramp section 442b acts on the rod head 424b on the limiting rod 424, a component needs to be designed on the rod head 424b to correspond and cooperate with the driving end 442c. The part of the rod head 424b that contacts the driving end 442c can be a point or a surface. In this embodiment, the rod head 424b is designed as a cylinder with multiple surfaces, and the left end face of the rod head 424b is defined as the receiving end 424c to cooperate with... The drive end 442c is matched, and further, the receiving end 424c is designed as an inclined surface with the same tilt angle as the drive end 442c, and there is a gap 46 between the drive end 442c and the receiving end 424c. Moreover, the receiving end 424c should be completely located within the second track cavity 143d. If the receiving end 424c is located within the first track cavity 143c, the limiting rod 424 cannot move. This is also the reason why the width of the second track cavity 143d is greater than that of the first track cavity 143c.

[0050] The left end face of the movable part 42 needs to abut against the right end face of the fixed part 41 to produce a braking effect. If the movable part 42 acts directly on the fixed part 41, it will cause significant wear to both over long-term use. Therefore, an intermediate part 43 can be added to the surface of the fixed part 41 or the movable part 42. The intermediate part 43 has the same diameter as the first chassis 411 or the second chassis 421, and the intermediate part 43 abuts against the other one of them to perform braking. In this embodiment, the intermediate part 43 is fixed to the left end face of the movable part 42. Furthermore, since the first chassis 411 should not be designed to be too thick... Furthermore, the first chassis 411 rotates together with the drive shaft 23. Relying solely on the threaded hole 414 on the first chassis 411 will inevitably cause the connection between the drive shaft 23 and the first chassis 411 to become loose. Therefore, a first flange 412 and a second flange 413 can be added to the left and right end faces of the first chassis 411. At this time, the length of the threaded hole 414 increases to the distance from the left end face of the first flange 412 to the right end face of the second flange 413. It is worth noting that at this time, the intermediate part 43 needs to have a through hole 431, and the diameter of the through hole 431 should be larger than the outer diameter of the second flange 413.

[0051] The braking process of braking component 4 will be described next. Please refer to [link / reference]. Figures 12 to 15 As shown, the trigger 32 has a first position for closing the motor assembly 2 and a second position for starting the motor assembly 2. In the first position, the first contact 323 does not press the linkage 44, the second contact 324 does not press the button 311, the receiving end 424c and the driving end 442c are spaced apart, and the intermediate part 43 and the fixing part 41 are in contact. When the trigger 32 is pressed, the driving end 442c moves upward and drives the receiving end 424c to move to the right, and then the first elastic part 425 is compressed, thereby causing the movable part 42 and the intermediate part 43 to move to the right. At this time, the drive shaft 23 rotates without restriction. When the trigger 32 is reset, since the receiving end 424c is not pressed, the movable part 42 drives the intermediate part 43 to move to the left. At this time, the drive shaft 23 is still rotating under the inertial drive after the power is cut off. When the intermediate part 43 reaches the first chassis 411, the intermediate part 43 performs friction braking on the first chassis 411, and the drive shaft 23 immediately stops running.

[0052] It is worth noting that the gap 46 between the drive end 442c and the receiving end 424c can compensate for the braking wear of the intermediate part 43. For details, please refer to [link / reference needed]. Figures 16 to 19 As shown: Figure 16 In the current state, the angle grinder 100 is in a stopped state, with a gap 46 between the drive end 442c and the receiving end 424c. The moving part 42 and the intermediate part 43 abut against the fixed part 41 under the action of the first elastic element 425, wherein the first elastic element 425 is in a compressed state throughout the braking process. Next, we will discuss the case where there is no gap between the drive end 442c and the receiving end 424c, such as... Figure 17As shown, the initial position of the driving end 442c is moved upward to abut against the receiving end 424c, so that the driving end 442c generates a rightward preload force on the receiving end 424c. However, the driving end 442c does not cause the receiving end 424c to move to the right at this time, and the intermediate part 43 just abuts against the fixing part 41. After a long period of braking, the intermediate part 43 will be missing. Here, the missing part of the intermediate part 43 is defined as the wear section 432, as shown. Figure 18 As shown, in this situation, the moving part 42 and the intermediate part 43 have lost their braking effect because the driving end 442c restricts the receiving end 424c. The distance between the intermediate part 43 at its extreme position on the left end and the fixed part 41 is equal to the width of the worn section 432. The braking situation of the intermediate part 43 after wear will be described next. Figure 16 The gap between the drive end 442c and the receiving end 424c is referenced. Figure 18 and Figure 19 When the intermediate part 43 wears down, due to the presence of the gap 46, the receiving end 424c relative to the... Figure 18 The position of the middle part 43 has moved to the left, and the middle part 43 has also moved to the left until it comes into contact with the fixed part 41. At this time, the driving end 442c comes into contact with the receiving end 424c, or there is still a certain distance between the driving end 442c and the receiving end 424c. That is, the wear section 432 of the middle part 43 can be compensated by the gap 46 between the driving end 442c and the receiving end 424c.

[0053] 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, a motor assembly housed within the housing, a control assembly for driving the motor assembly, and a braking assembly for braking the motor assembly, the motor assembly having a central axis extending in a left-right direction along the housing and a drive shaft rotating about the central axis, the control assembly including a trigger for controlling the motor assembly, the trigger having a first position of closing the motor assembly and a second position of starting the motor assembly, the braking assembly including a fixing member mounted to the drive shaft and a movable member that brakes the motor assembly by friction with the fixing member; characterized in that: The braking assembly has a linkage connecting the trigger and the movable member. The movable member has a limit rod protruding from its end face away from the fixed member. The linkage includes a drive end corresponding to the limit rod. The limit rod has a receiving end that cooperates with the drive end. The drive end and the receiving end are in inclined contact. In the first position, a gap is formed between the receiving end and the drive end. In the second position, the receiving end abuts against the drive end to drive the movable member to move left and right. An intermediate member is provided between the fixed member and the movable member. The end face of the linkage away from the receiving end extends in the direction of the central axis beyond the end face of the intermediate member facing the movable member. The intermediate member has a wear section caused by friction braking between the fixed member and the movable member. The gap provides wear compensation for the wear section.

2. The grinding tool according to claim 1, characterized in that: One of the fixed member and the movable member is fitted with the intermediate member, and abuts against the other through the intermediate member to brake the motor assembly.

3. The grinding tool according to claim 2, characterized in that: The fastener includes a first chassis in the shape of a circle, and the intermediate component is mounted on the first chassis.

4. The grinding tool according to claim 2, characterized in that: The movable component includes a second chassis corresponding to the fixed component, and the intermediate component is mounted on the second chassis.

5. The grinding tool according to claim 4, characterized in that: The housing has a accommodating compartment for receiving the braking assembly, the braking assembly has a support mounted in the accommodating compartment, and the movable member is connected to the support via a first elastic member.

6. The grinding tool according to claim 5, characterized in that: The limiting rod includes a rod body installed on the second chassis and a rod head extending from the rod body, with the receiving end disposed on the rod head.

7. The grinding tool according to claim 5, characterized in that: The accommodating compartment has a guide hole penetrating the bottom surface and a track communicating with the guide hole. The linkage includes a base plate and a slide plate extending from the base plate. The trigger is connected to the base plate, and the slide plate passes through the guide hole and moves in the track.

8. The grinding tool according to claim 7, characterized in that: The slide plate includes a straight section extending from the substrate and a ramp section integrally formed with the straight section, and the drive end is integrated into the ramp section.

9. A grinding tool, comprising a housing, a motor assembly housed within the housing, a control assembly for driving the motor assembly, and a braking assembly for braking the motor assembly, the motor assembly having a central axis extending in a left-right direction along the housing and a drive shaft rotating about the central axis, the control assembly including a trigger for controlling the motor assembly, and the braking assembly including a fixing member mounted to the drive shaft and a movable member that brakes the motor assembly by friction with the fixing member; characterized in that: The braking assembly has a linkage connecting the trigger and the movable member. The movable member has a limit rod on its end face away from the fixed member. When the trigger activates the motor assembly, the trigger drives the linkage to move up and down and abut against the limit rod, thereby driving the movable member to move left and right. The braking assembly has a second elastic member that biases the linkage. When the trigger is in the position where the motor assembly is closed, at least a portion of the movable member is spaced apart from the linkage. An intermediate member is provided between the fixed member and the movable member. When the intermediate member wears, the movable member moves to drive the intermediate member to abut against the fixed member.

10. The grinding tool according to claim 9, characterized in that: The housing is provided with a mounting groove, and the second elastic element is fixed to the mounting groove.

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