Power tool

Abstract

This invention relates to a power tool with a detachably mounted working head. The power tool includes a housing, an output shaft extending from the interior of the housing, and a clamping mechanism for fixing the working head to the output shaft. The clamping mechanism has an operating member, a pressure-bearing member connected to the operating member, a first force-applying component that applies force to the pressure-bearing member, a locking member installed within the output shaft, and a second force-applying component that applies force to the locking member. The operating member drives the pressure-bearing member to switch between a locked position and an unlocked position. When the pressure-bearing member is in the locked position, the locking member is locked in an expanded state, and the second force-applying component has a first compression amount. When the pressure-bearing member is in the unlocked position, the locking member switches to a closed state, and the second force-applying component has a second compression amount, which is greater than the first compression amount. This invention uses the second force-applying component to elastically clamp the working head, resulting in good durability and wear resistance of the working head.

Description

[Technical Field]

[0001] This invention relates to a power tool, and more particularly to a power tool used in decoration, construction and other similar applications. [Background Technology]

[0002] A multi-tool is a power tool that uses the rotational force of an electric motor to provide torque to a working head, thereby performing machining operations on a workpiece. It holds an irreplaceable position in industries such as decoration and construction. A multi-tool is driven by a motor-driven motion conversion mechanism, which in turn causes the output shaft to reciprocate along its axis. Operators can attach different types of working attachments to the output shaft to perform operations such as cutting, polishing, or grinding, thus enabling the multi-functional tool to meet diverse operational needs.

[0003] Currently, most multi-tools on the market use a threaded connection for their working heads. This means that a threaded blind hole is located at the bottom of the pressure-bearing component, and a bolt passes through the working head and connects directly to this hole. When changing working heads or accessories, multiple rotations with a wrench are required to remove the working head. Even after replacing it with a new working head, the wrench still needs to be rotated multiple times to secure it. Therefore, changing working heads is cumbersome, reduces work efficiency, and can result in failure to tighten the head properly. Furthermore, prolonged use can lead to thread fatigue wear and stripping, causing the working head clamping to fail.

[0004] For improvements to the above structure, please refer to Chinese Utility Model Patent No. CN212286098U, published on January 5, 2021. This patent discloses a oscillating machine for quick head changing. When the wrench is manually turned less than half a turn, it causes an eccentric block to rotate slightly around its central hole. Utilizing the principle of an eccentric cam, the eccentric block applies pressure to the push rod, causing the lower connector at the bottom of the push rod to open a certain distance, allowing the working head to easily fit onto the toothed locating pin of the upper connector. Simultaneously, the spring inside the output shaft is compressed. When the wrench returns to its original position, the eccentric block will no longer press against the push rod, and the spring will rebound. This technical solution uses a spring to provide the clamping force for the working head, avoiding the drawbacks of loose screws and stripped teeth caused by manual screw tightening. However, this solution can only clamp semi-open saw blades and lacks compatibility. Furthermore, the working head is rigidly fixed by the upper and lower connectors, which can easily damage the working head, leading to clamping failure and affecting the normal use of the multi-functional tool.

[0005] Therefore, it is indeed necessary to provide an improved power tool to overcome the shortcomings of the existing technology. [Summary of the Invention]

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a power tool for quick head changing.

[0007] The present invention solves the problems of the prior art by adopting the following technical solution: an electric tool, detachably equipped with a working head, the electric tool including a housing, an output shaft extending from the interior of the housing, and a clamping mechanism for fixing the working head to the output shaft; the clamping mechanism has an operating member, a pressure-bearing member connected to the operating member, a first force-applying member applying force to the pressure-bearing member, a locking member installed in the output shaft, and a second force-applying member applying force to the locking member; the operating member drives the pressure-bearing member to switch between a locked position and an unlocked position; when the pressure-bearing member is in the locked position, the locking member is locked in an expanded state, and the second force-applying member has a first compression amount; when the pressure-bearing member is in the unlocked position, the locking member switches to a closed state, and the second force-applying member has a second compression amount, the second compression amount being greater than the first compression amount.

[0008] A further improvement is as follows: the locking member has a first axial position and a second axial position. When the locking member is in the first axial position, it is in a clamping mode that can clamp the working head; when the locking member is in the second axial position, it is in a disassembly mode that allows the working head to be released or installed.

[0009] A further improvement is as follows: the operating component has an operating wrench and a drive cam connected to the operating wrench, the drive cam being operable to engage and disengage from the pressure-bearing component.

[0010] A further improvement is as follows: the pressure-bearing member has a rod extending axially along the output shaft and a handle connected to the rod, one end of the first force-applying member abuts against the inner wall of the output shaft, and the other end abuts against the outer wall of the handle.

[0011] A further improvement is as follows: the handle has a first driving portion distributed on both sides of the rod and a second driving portion recessed away from the locking member from the first driving portion, and the first driving portion and the second driving portion work together on the locking member.

[0012] A further improvement is that the locking member has at least two jaws and a locking pin that connects the jaws to the output shaft, the locking pin being inserted between the output shaft and the jaws.

[0013] A further improvement is that the two grippers are symmetrically arranged along the axis of the output shaft.

[0014] A further improvement is as follows: the gripper has a rocker portion located between the first driving portion and the second force-applying component and a rotating portion protruding from the rocker portion, and the locking pin passes through the rotating portion.

[0015] A further improvement is that the gripper has legs connected to the rocker section and feet protruding from the legs toward the inner wall of the output shaft, and the two legs expand and close around the rotating part.

[0016] A further improvement is that the clamping mechanism also has a fixing block fixed to the output shaft, and the working head is locked between the fixing block and the foot.

[0017] A further improvement is as follows: when the pressure-bearing component is in the locked position, the second force-applying component applies an upward force to the rocker portion to clamp the working head, and the elastic force of the second force-applying component is greater than the elastic force of the first force-applying component.

[0018] A further improvement is as follows: when the pressure-bearing component is in the unlocked position, the drive cam and the first force-applying component apply a downward force to the rocker portion, driving the locking component to move downward, so as to install or remove the working head.

[0019] Compared with the prior art, the present invention has the following advantages: the working head is elastically clamped by the second force-applying component. When the pressure member is in the locked position, the second force-applying component applies an upward force to the locking member to keep it in an expanded state, so as to achieve a better clamping effect, making the working head less prone to wear and more durable; in addition, the outer diameter of the legs when they are closed is smaller than the diameter of the mounting hole of the working head, which facilitates the assembly of various working heads and has good compatibility. [Attached Image 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 schematic diagram of the structure of a power tool adapted to a working head according to a preferred embodiment of the present invention;

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

[0023] Figure 3 yes Figure 2 A magnified view of a portion of the power tool shown;

[0024] Figure 4 yes Figure 2 The diagram shows the structure of the shift fork assembly.

[0025] Figure 5 yes Figure 2 A cross-sectional view of the clamping mechanism in its first state;

[0026] Figure 6 yes Figure 5 A cross-sectional view of the clamping mechanism in its second state;

[0027] Figure 7 yes Figure 5 The clamping mechanism shown is in its third state (sectional view).

[0028] Figure 8 yes Figure 5 A partially enlarged view of the clamping mechanism shown.

Detailed Implementation Methods

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0030] The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," "rear," "left," and "right" 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.

[0031] Please see Figure 1 and Figure 2 As shown, the embodiments of the present invention relate to a power tool, and a multi-function tool 100 is a preferred embodiment of this embodiment, which is widely used in decoration, construction and other fields. The multi-function tool 100 includes a housing 1, a drive mechanism 2 housed within the housing 1, a control component 3 electrically connected to the drive mechanism 2, an output shaft 4 connected to the front end of the drive mechanism 2 and extending from the inside of the housing 1 to the outside, and a clamping mechanism 6 for fixing a working head 101 to the output shaft 4. The output shaft 4 can be adapted to various different working heads 101 to achieve various different operating functions, such as cutting, polishing or grinding operations, thereby meeting different operational needs.

[0032] In this embodiment, the aforementioned housing 1 includes a main housing 11 extending longitudinally along the front-rear direction and a head housing 12 connected to the front end of the main housing 1. The drive mechanism 2 is housed within the main housing 11 and located at the front end of the main housing 11. Specifically, the main housing 11 has a first housing 111 for housing the drive mechanism 2, a grip portion 112 located at the rear end of the first housing 111, and a battery pack insertion portion 113, the battery pack insertion portion 113 being detachably connected to the battery pack 102.

[0033] Specifically, the drive mechanism 2 includes a motor assembly 21 and a motion conversion mechanism 22 housed within the main housing 11. The motion conversion mechanism 22 is connected between the motor assembly 21 and the output shaft 4. The motor assembly 21 drives the motion conversion mechanism 22, thereby causing the output shaft 4 to perform a reciprocating oscillating motion.

[0034] In this embodiment, the output shaft 4 is arranged perpendicular to the main housing 11, with one end installed inside the head housing 12 and the other end extending downward to the outside of the head housing 12. The axis of the output shaft 4 intersects the axis of the motor assembly 21. One end of the output shaft 4 is connected to the motion conversion mechanism 22, and the other end is connected to the working head 101.

[0035] Furthermore, the working head 101 is detachably mounted on the lower end of the output shaft 4. Therefore, the motion conversion mechanism 22 drives the working head 101 and the output shaft 4 to move synchronously, that is, the working head 101 and the output shaft 4 can swing back and forth around the axis X of the output shaft 4.

[0036] Please refer to the following: Figure 2 As shown, the control component 3 includes a toggle switch 32 movably connected to the main housing 11, a switch 31 connected to the toggle switch 32, a speed control knob 33 for adjusting the speed of the motor assembly 21, and an electronic control board 34 electrically connected to the switch 31, the speed control knob 33, and the motor assembly 21. Pushing the toggle switch 32 to move it axially can open / close the switch 31. The electronic control board 34 is located at the front end of the battery pack connector 113 and is electrically connected to the battery pack 102 to control the motor assembly 21 to be in an active or inactive state.

[0037] Combination Figure 3 As shown, the motor assembly 21 includes a motor 211, a rotor shaft 212 passing through the motor 211, and an eccentric block 215 located at the front end of the rotor shaft 212. The eccentric block 215 is integrally formed with the rotor shaft 212 or is fixedly installed separately. The rotor shaft 212 is supported at both ends by a first bearing 213 and a second bearing 214 to reduce friction and improve rotational accuracy. The eccentric block 215 is located at the front end of the first bearing 213, and the axis of the eccentric block 215 does not coincide with the axis of the rotor shaft, that is, the eccentric block 215 can rotate eccentrically around the axis of the rotor shaft 212.

[0038] In this embodiment, the motion conversion mechanism 22 includes a shift fork assembly 222 connecting the eccentric block 215 and the output shaft 4, a ball bearing 223 sleeved on the outer periphery of the eccentric block 215, and a counterweight 221. Preferably, the center of gravity of the counterweight 221 and the eccentric block 215 is at 180° to reduce vibration.

[0039] Combination Figure 4As shown, the shift fork assembly 222 has a mounting hole 2221 for mounting the output shaft 4, a connecting rod 2222 extending outward from the sidewalls at both ends of the mounting hole 2221, a lever 2223 connecting the connecting rod 2222, and a crossbeam 2224 located between the levers 2223. The levers 2223 and the crossbeam 2224 form a shaped groove, and the ball bearing 223 is located between the levers 2223 and housed within the shaped groove. When the multi-function tool 100 is in operation, the motor 211 drives the eccentric block 215 and the ball bearing 223 to rotate eccentrically around the rotor shaft 212. During the rotation of the ball bearing 223, it periodically strikes the lever 2223 of the shift fork assembly 222, thereby causing the connecting rod 2222 to drive the output shaft 4 to swing.

[0040] Please refer to the following: Figures 5 to 8 As shown, the clamping mechanism 6 includes an operating member 61, a pressure-bearing member 64 connected to the operating member 61, a first force-applying member 62 that applies force to the pressure-bearing member 64, a locking member 65 installed in the output shaft 4, a second force-applying member 63 that applies force to the locking member 65, a fixing block 66 fixed to the output shaft 4, and a first locking feature 67 connected to the output shaft 4. The first locking feature 67 is shaped-locked with the second locking feature 101a on the working head 101 to fix the working head 101 to the clamping mechanism 6.

[0041] In this embodiment, the operating member 61 drives the pressure member 64 to switch between a locked position and an unlocked position. Specifically, rotating the operating member 61 causes the pressure member 64 to move up and down. The operating member 61 has an operating lever 611, a driving cam 612 connected to the operating lever 611, and a rotating pin 613 passing through the operating lever 611. The operating lever 611 is fixedly connected to the driving cam 612. Rotating the operating lever 611 causes the driving cam 612 to rotate around the rotating pin 613, so that the driving cam 612 can be operably disengaged from the pressure member 64 (i.e., there is contact or gap between the driving cam 612 and the pressure member 64, at which time the pressure member 64 is in the locked position) and engaged (i.e., the driving cam 612 presses against the pressure member 64, causing it to move downwards to at least the unlocked position).

[0042] When the pressure-bearing member 64 is in the aforementioned locked position, the locking member 65 is locked in the expanded state, at which time the working head 101 is fixed on the output shaft 4. Furthermore, the first force-applying member 62 is in a pre-compression state with only a small third compression amount, while the second force-applying member 63 is configured to have a first compression amount, which is much greater than the third compression amount. The second force-applying member 63 applies an upward force to the locking member 65, keeping it in the expanded state, thereby fixing the working head 101 between the locking member 65 and the fixing block 66.

[0043] When the pressure-bearing member 64 is in the unlocked position, the locking member 65 switches to the closed state, at which point the working head can be released or installed. Furthermore, the second force-applying member 63 is compressed by external force to have a second compression amount, which is greater than the first compression amount. The pressure-bearing member 64 transmits downward pressure, forcing the locking member 65 to close and move downward, thereby facilitating the installation / removal / replacement of the working head 101.

[0044] In this embodiment, the first force-applying component 62 and the second force-applying component 63 may be springs or other elastic elements. Preferably, the elastic force of the second force-applying component 63 is greater than the elastic force of the first force-applying component 62.

[0045] In this embodiment, the pressure-bearing member 64 has a rod portion 641 extending axially along the output shaft 4 and a handle portion 642 connected to the lower end of the rod portion 641. A first force-applying member 62 is sleeved on the outer periphery of the rod portion 641, with one end of the first force-applying member 62 abutting against the inner wall of the output shaft 4 and the other end abutting against the outer wall of the handle portion 642. The rod portion 641 is used to engage the drive cam 612, and the handle portion 642 is used to engage the locking member 65.

[0046] Specifically, the rod portion 641 can be a cylinder, which facilitates sliding up and down inside the small diameter portion of the output shaft; the handle portion 642 has a left-right symmetrical structure, which has a first driving portion 642a distributed on both sides of the rod portion 641 and a second driving portion 642b recessed from the first driving portion 642a away from the locking member 65. The first driving portion 642a and the second driving portion 642b work together to lock the member 65.

[0047] In this embodiment, the locking member 65 has at least two jaws 651 and a locking pin 652 that connects the jaws 651 to the output shaft 4. The locking pin 652 passes through the output shaft 4 and the jaws 651, and the jaws 651 are rotatably connected around the locking pin 652.

[0048] Preferably, the two grippers 651 are symmetrically arranged along the axis of the output shaft 4.

[0049] The locking member 65 has a first axial position and a second axial position. When the locking member 65 is in the first axial position, the locking member 65 is in a clamping mode that can clamp the working head 101. When the locking member 65 is in the second axial position, the locking member 65 is in a disassembly mode that allows the release or installation of the working head 101.

[0050] Combination Figure 8As shown, the gripper 651 has a rocker portion 651a located between the first drive portion 642a and the second force application member 63, a rotating portion 651b protruding from the end of the rocker portion 651a, a leg portion 651c connected to the rocker portion 651a, and a foot portion 651d protruding from the leg portion 651c toward the inner wall of the output shaft 4. The locking pin 652 passes through the rotating portion 651b, so that the two legs 651c can expand and close around the rotating portion 651b.

[0051] Specifically, the first drive part 642a is distributed correspondingly to the rocker part 651a. When the operating member 61 is turned clockwise, the pressure member 64 moves to the unlocked position. The drive cam 612 and the first force-applying member 62 apply a downward force to the locking member 65. The first drive part 642a pushes the rocker part 651a to rotate downward around the locking pin 652 until the rotating part 651b contacts the second drive part 642b. Then the first drive part 642a and / or the second drive part 642b push the locking member 65 to move downward to install or remove the working head 101.

[0052] Preferably, the outer diameter of the two legs 651c when they are closed is configured to be smaller than the diameter of the mounting hole of the working head 101, so as to facilitate the assembly of various working heads and meet the requirements of compatibility.

[0053] When the operating component 61 is turned counterclockwise, the pressure-bearing component 64 moves to the locked position. The second force-applying component 63 applies an upward force to the locking component 65. The second force-applying component 63 pushes the rocker arm 651a to rotate upward around the locking pin 652, and the leg 651c expands to both sides and then moves upward, locking the working head 101 between the fixing block 66 and the foot 651d. The second force-applying component 63 provides elastic clamping for the working head 101, preventing damage to the working head.

[0054] Preferably, the outer diameter of the two legs 651c when open is configured to be larger than the diameter of the mounting hole of the working head 101.

[0055] The present invention uses the second force-applying component 63 to elastically clamp the working head 101. When the pressure-bearing component 64 is in the locked position, the second force-applying component 63 applies an upward force to the locking component 65 to keep it in an expanded state, thereby achieving a better clamping effect, making the working head less prone to wear and more durable. In addition, the outer diameter of the legs 651c when they are closed is smaller than the diameter of the mounting hole of the working head 101, which facilitates the assembly of various working heads and has good compatibility.

[0056] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many other alternatives to the power tools of this invention can be developed 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 power tool having a detachably mounted working head, the power tool comprising a housing, an output shaft extending from the interior of the housing, and a clamping mechanism for fixing the working head to the output shaft; characterized in that: The clamping mechanism includes an operating member, a pressure-bearing member connected to the operating member, a first force-applying component that applies force to the pressure-bearing member, a locking member installed in the output shaft, and a second force-applying component that applies force to the locking member. The operating member drives the pressure-bearing member to switch between a locked position and an unlocked position. When the pressure-bearing member is in the locked position, the locking member is locked in an expanded state, and the second force-applying component has a first compression amount. When the pressure-bearing member is in the unlocked position, the locking member switches to a closed state, and the second force-applying component has a second compression amount, which is greater than the first compression amount. The pressure-bearing member has a rod extending axially along the output shaft and first driving portions distributed on both sides of the rod. The first driving portions act on the locking member. The locking member has a jaw and a locking pin connecting the jaw to the output shaft. The jaw has a rocker portion located between the first driving portion and the second force-applying component and a rotating portion protruding from the rocker portion. The first driving portion pushes the rocker portion to rotate around the locking pin.

2. The power tool according to claim 1, characterized in that: The locking member has a first axial position and a second axial position. When the locking member is in the first axial position, it is in a clamping mode that can clamp the working head. When the locking member is in the second axial position, it is in a disassembly mode that allows the working head to be released or installed.

3. The power tool according to claim 2, characterized in that: The operating component has an operating wrench and a drive cam connected to the operating wrench, the drive cam being operable to engage and disengage from the pressure bearing component.

4. The power tool according to claim 3, characterized in that: The pressure-bearing member has a handle connected to the rod, and one end of the first force-applying member abuts against the inner wall of the output shaft, and the other end abuts against the outer wall of the handle.

5. The power tool according to claim 4, characterized in that: The handle has a second driving portion recessed away from the locking member from the first driving portion, and the first driving portion and the second driving portion work together on the locking member.

6. The power tool according to claim 5, characterized in that: The locking member has at least two jaws, and the locking pin passes between the output shaft and the at least two jaws.

7. The power tool according to claim 6, characterized in that: The two grippers are symmetrically arranged along the axis of the output shaft.

8. The power tool according to claim 7, characterized in that: The locking pin passes through the rotating part.

9. The power tool according to claim 8, characterized in that: The gripper has legs connected to the rocker section and feet protruding from the legs toward the inner wall of the output shaft, the two legs expanding and closing around the rotating section.

10. The power tool according to claim 9, characterized in that: The clamping mechanism also has a fixing block fixed to the output shaft, and the working head is locked between the fixing block and the foot.

11. The power tool according to claim 10, characterized in that: When the pressure-bearing component is in the locked position, the second force-applying component applies an upward force to the rocker portion to clamp the working head. The elastic force of the second force-applying component is greater than the elastic force of the first force-applying component.

12. The power tool according to claim 10, characterized in that: When the pressure-bearing component is in the unlocked position, the drive cam and the first force-applying component apply a downward force to the rocker portion, driving the locking component to move downward, so as to install or remove the working head.

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