CN217890875U

CN217890875U - Electric tool

Info

Publication number: CN217890875U
Application number: CN201990001402.XU
Authority: CN
Inventors: 黄康; 麻立国; 任宏胜
Original assignee: Techtronic Cordless GP
Current assignee: Techtronic Cordless GP
Priority date: 2019-06-20
Filing date: 2019-06-20
Publication date: 2022-11-25
Anticipated expiration: 2029-06-20
Also published as: WO2020252737A1

Abstract

An electric tool (1), in particular an electric stapler, is provided. The power tool (1) comprises a drive mechanism (10) for driving fasteners into an object, a motor (20) adapted to actuate the drive mechanism (10), a rotatable member (30) rotatable by the motor (20), and an operating mechanism (60) for controlling the motor (20) to be energized and de-energized. The operating mechanism (60) includes a first switch (62) and a second switch (64). The first switch (62) is normally biased to an open position and when a user of the power tool (1) presses the first switch (62), the first switch is turned to a closed position to energize the motor (20). The second switch (64) is normally biased to an open position and is adapted to be rotated to a closed position to energize the motor (20) when the first switch (62) is in its open position. The operating mechanism (60) is configured to mechanically control the on/off of the motor (20) via the second switch (64).

Description

Electric tool

Technical Field

The utility model relates to an electric tool. More particularly, but not exclusively, the invention relates to a power tool having a drive mechanism actuated by a motor and an operating mechanism for controlling the motor to be powered on and off.

Background

A typical power tool includes a housing, a motor mounted on the housing, and a drive mechanism that is activated by the motor to perform a particular operation and is deactivated upon completion of the operation. For actuating the drive mechanism, a spindle is also provided within the housing and is rotatably driven by the motor. A spindle lock is also provided for engaging against the spindle to prevent rotation of the spindle.

Such prior power tools basically require an electronic control system having an overrunning clutch for preventing undesired reverse rotation of the spindle, and a mechanical transmission in electronic communication with a sensor for manipulating the drive wheel. When the electronic control system triggers the sensor, the motor stops further rotation and the biasing force resists the inertia of the drive wheel in the opposite direction. The overrunning clutch thereby limits reverse rotation of the drive wheel, thus stopping the main shaft at a desired position.

However, this configuration has a number of disadvantages. To meet the technical requirements, high-precision electronic control systems and sensors are required. Furthermore, the overrunning clutch is very bulky, and therefore this inevitably limits the minimum size of the main shaft lock mechanism. In addition, the overrunning clutch relies on friction, so that the internal components may wear at some point.

SUMMERY OF THE UTILITY MODEL

According to one aspect of the present invention, an electric tool (1), in particular an electric stapler, is provided, comprising:

a drive mechanism (10) for driving a fastener into an article,

a motor (20) adapted to actuate the drive mechanism (10),

a rotatable member (30) rotatable by the motor (20), and

an operating mechanism (60) for controlling the energization and de-energization of the motor (20),

wherein the operating mechanism (60) comprises a first switch (62) and a second switch (64),

the first switch (62) is normally biased to an open position and when a user of the power tool (1) presses the first switch (62), the first switch is turned to a closed position to energize the drive motor (20),

the second switch (64) is normally biased to an open position and is adapted to be turned to a closed position to energize the drive motor (20) when the first switch (62) is in its open position.

Preferably, the second switch (64) is actuated by the rotatable member (30) to energise the drive motor (20) when the first switch (62) is in its off position.

More preferably, the rotatable member (30) comprises a cam (40) and the second switch (64) is triggered by a cam follower (50) of the cam (40).

Even more preferably, the cam (40) includes a first surface (42) and a second surface (44); the second switch (64) remains biased to an open position during engagement of the cam follower (50) and the first surface (42); during engagement of the cam follower (50) and the second surface (44), the second switch (64) is rotated to the closed position to energize the drive motor (20).

Still more preferably, the transition from the first surface (42) to the second surface (44) in the first rotational direction is in a gradual manner such that the second switch (64) switches from the open position to the closed position when the rotatable member (30) has rotated a first portion of a predetermined period.

Still more preferably, the transition from the first surface (42) to the second surface (44) in the second rotational direction is in a stepwise manner such that the second switch (64) switches from the closed position to the open position when the rotatable member (30) has rotated a second portion of the predetermined period.

Even more preferably, the second switch (64) is triggered by a tilting movement of the cam follower (50).

Still more preferably, the cam follower (50) is provided as a lever by which the pressing force exerted on the second switch (64) by the cam (40) is amplified.

Optionally, the lever is pivotable about a fulcrum (52).

Preferably, the second switch (64) is spaced from the fulcrum (52) by a distance L1, and the cam (40) is spaced from the fulcrum (52) by a distance L2, L2 being different from L1.

According to another aspect of the present invention, there is provided an electric tool (1), in particular an electric stapler, comprising:

a drive mechanism (10) for driving a workpiece into an article, the drive mechanism (10) normally biased to a rest position and rotated to an energy storage position to drive the workpiece into the article,

a motor (20) for actuating the drive mechanism (10), and

a rotatable member (30) rotatable about a rotation axis (31) by the motor (20),

a locking mechanism (70) for locking the rotatable member (30) in a locked position when the drive motor (20) is deactivated by the operating mechanism (60),

wherein the locking mechanism (70) comprises a female member, a biasing means (14) and a male member (32) adapted to engage the female member and resist the biasing means (14) during engagement such that the rotatable member (30) is balanced in the locking position.

Preferably, the female member is mounted to the drive mechanism (10) and the male member comprises a pin (32), the pin (32) being mounted on the rotatable member (30) to move in a circumferential direction, the female member being adapted to prevent the pin (32) from moving during engagement.

More preferably, the female member includes a receiving portion (80) that is biased to move against the pin (32) to lock the pin (32) against further movement of the pin (32) when the drive motor (20) is deactivated by the operating mechanism (60).

Even more preferably, the receiving portion (80) includes a profile that is substantially complementary to the shape of the pin (32).

Still more preferably, the receiving portion (80) includes a wedge-shaped slot (90) for receiving the pin (32) when the motor (20) is deactivated.

Preferably, the wedge-shaped groove (90) is formed by two inclined surfaces (92, 94), one of which is disposed at a predetermined angle (a) to the other.

Optionally, each of the two inclined surfaces (92, 94) applies two opposing forces to the pin (32) to hold the pin (32) in place.

Alternatively, the two inclined surfaces (92, 94) are arranged at different inclinations.

According to another aspect of the invention, a method for operating a power tool (1) is provided, the method comprising the steps of:

a) Pressing against the drive mechanism (10) by the rotatable member (30) being positioned in the locked position to store potential energy in the drive mechanism;

b) Turning a first switch (62) to a closed position to energize a drive motor (20) to trigger rotation of the rotatable member (30);

c) Turning a second switch (64) to a closed position by the rotatable member (30) when the rotatable member (30) has rotated a first portion of a predetermined period;

d) Releasing potential energy stored in the drive mechanism (10) when the rotatable member (30) has rotated for a second portion of the predetermined period; and

e) Releasing the second switch (64) to an off position to lock the rotatable member (30) in the locked position when the rotatable member (30) has rotated a third portion of the predetermined period.

Preferably, the method further comprises a step d 1) of releasing the first switch (62) to an open position after step d), so that the drive motor (20) remains energized through the second switch (64) during a third portion of the predetermined period.

Preferably, the motor (20) is energized through at least one of the first switch (62) and the second switch (64) throughout a predetermined period.

The present invention seeks to obviate or at least mitigate one or more of the above-mentioned disadvantages by providing a new or improved power tool incorporating a mechanical drive train, which may reduce manufacturing costs, repair or maintenance frequency. Compared with the prior art, the utility model provides a stop mechanism does not need complicated electronic control circuit, especially need not be used for the sensor of the rotational position of rotatable component. Instead, the rotatable member is stopped at a certain position using the cam portion of the rotatable member and the associated mechanical switch, and this position can be accurately set in advance. In addition, the present invention does not require an overrunning clutch, but rather locks the rotatable member through mechanical structures (e.g., V-shaped wedges) in the self-locking mechanism, which saves cost, reduces the complexity of the structure, and greatly reduces the possibility of failure.

Drawings

In order that the invention may be more fully understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

fig. 1 schematically shows a perspective view of a spindle lock of a binding machine according to an embodiment of the invention.

Figure 2 schematically illustrates a perspective view of a rotatable member of the spindle lock of figure 1.

Figure 3 schematically illustrates a perspective view of the cam and cam follower of the spindle lock of figure 1.

Fig. 4 schematically illustrates the geometry of the cam follower of fig. 3.

Figure 5 schematically illustrates a perspective view of the locking mechanism of the spindle lock of figure 1.

Figure 6 schematically illustrates a logic diagram of the spindle lock of figure 1.

Fig. 7 is a free body view of a pin of the locking mechanism of fig. 5.

In these figures, like parts are denoted by like reference numerals.

It is to be understood that the drawings are for illustrative purposes only and are not drawn to scale.

Detailed Description

Fig. 1 illustrates a power tool 1, particularly a power stapler, including a drive mechanism 10 for driving a fastener (e.g., a staple or pin) into a workpiece such as a clamp. The drive mechanism 10 includes a slide 12 movable between a rest position and an energy storage position. The drive mechanism 10 further includes a biasing device 14 for normally biasing the slide 12 toward the rest position.

The drive mechanism 10 is actuated by a motor 20. Actuation of motor 20 is controlled by operating mechanism 60. The motor 20 comprises a motor shaft 22 on which a rotatable member 30 is arranged, which rotates together with the motor shaft 22 about a rotation axis 31. The rotatable member 30 further includes a pin 32. The pin 32 is positioned on the rotatable member 30 and offset from the axis of rotation 31 such that the pin is movable in the circumferential direction.

Energization and de-energization of the motor 20 is controlled by the operating mechanism 60. The operating mechanism 60 includes a trigger switch 62 and an internal switch 64. Either of the trigger switch 62 and the internal switch 64 is closed so that the motor 20 is energized. In this embodiment, the trigger switch 62 is also referred to as a first switch, and the internal switch 64 is referred to as a second switch.

The trigger switch 62 may be provided outside the housing of the power tool 1 so as to be depressed by the user. The internal switch 64 may be disposed inside the housing of the power tool 1. The internal switch 64 also includes a biasing device, such as a spring 65, for normally biasing the internal switch 64 to an off position to de-energize the drive motor.

Referring to fig. 2, the rotatable member 30 further includes a cam portion 40 (e.g., a cylindrical cam) and a cam follower 50 that cooperate to manipulate the closed and open positions of the internal switch 64. An internal switch 64 is positioned adjacent to and triggered by the cam follower 50. The cam portion 40 includes asymmetric surfaces at the periphery in its circumferential direction, in particular, uneven first and

second surfaces

42 and 44 on its surface for engaging one end of the cam follower 50. The first surface 42 and the second surface 44 are connected at both ends thereof, respectively. At one end, the first surface 42 transitions in a gradual transition in the first rotational direction through a ramp surface 43 to a second surface 44. At the other end, the second surface 44 transitions in a stepped manner in the second rotational direction to the first surface 42 via a stepped surface 45.

Referring to fig. 3, the cam follower 50 may be incorporated as an elongated member and be inclined about a fulcrum 52 secured to or integrally formed with the housing of the power tool 1. First end 54 of cam follower 50 is adjacent cam portion 40 and second end 56 of cam follower 50 is adjacent internal switch 64. When a load is applied to the first end 54, the second end 54 tilts in the opposite direction and depresses the internal switch 64.

Referring to fig. 4, a portion of cam follower 50 from first end 54 to fulcrum 52 has a length L2 and another portion of cam follower 50 from second end 56 to fulcrum 52 has a length L1. The lengths L1 and L2 may be the same as or different from each other. Preferably, the length L2 of the first end 54 is longer than the length L1 of the second end 56, such that a greater degree of tilt is required at the first end 54 to impart a lesser degree of tilt at the second end 56. This helps to more accurately control the activation and deactivation of the internal switch 64.

When cam follower 50 engages first surface 42, internal switch 64 is held biased to the off position by spring 65. Cam follower 50 is then depressed by second surface 44 when rotatable member 30 rotates for the first quarter of a cycle. Second end 54 of cam follower 50 will tilt about fulcrum 52 against the biasing force of spring 65 to engage internal switch 64. The cam follower 50 remains in the inclined position until the rotatable member 30 has rotated for the remaining period and the cam follower 50 reaches the stepped surface 45.

Turning now to fig. 5, the novel locking mechanism 70 for locking the pin 32 when the drive motor 20 is deactivated by the internal switch 64 of the operating mechanism 60 is described in detail. The locking mechanism 70 is secured to the drive mechanism 10. For example, the locking mechanism 70 includes a male member, a female member, and a biasing device 14. The male member may incorporate a pin 32 for engaging with the female member and resisting the biasing means 14 during engagement. Thus, the female member prevents further movement of the pin 32 so that the rotatable member 30 remains balanced in the locked position.

In particular, the locking mechanism 70 includes a receiving portion 80 having a profile that is substantially complementary to the shape of the pin 32. The receiving portion 80 is movable with the slider 12 between an energy storage position and a rest position. The receiving portion 80 may be disposed below the slider 12. Alternatively, the receiving portion 80 may also be integrally formed as part of the slider 12.

A detailed description of the receiving portion 80 will now be provided. On the profile of the receiving portion 80 facing the pin 32, a wedge-shaped or V-shaped groove 90 is provided. The V-shaped groove 90 is formed by two

inclined surfaces

92, 94 having different inclinations, one of which is disposed at a predetermined angle a to the other.

Referring to fig. 6, the operation of the electric stapler 1 is described. In the default configuration, the pin 32 remains stationary in the locked position. At step 101, the trigger switch 62 is initially depressed by the user to activate the motor 20. Rotatable member 30 is then rotated by motor 20 in a unidirectional direction (e.g., clockwise) and cam follower 50 engages first surface 42 at step 102. When the cam follower 50 engages the ramp surface 43, the internal switch 64 remains in the off position. The rotatable member 30 then continues to rotate and, upon passing the ramped surface 43, i.e., the rotatable member 30 has rotated a first portion of the period T, the cam follower 50 reaches the second surface 44 and engages the second surface 44. At step 103, cam follower 50 is tilted about fulcrum 52 against the biasing force of spring 65 to activate internal switch 64.

During steps 101 to 103, the pin 32 engages and presses the slider 12 against the biasing force of the spring 14. At step 104, further rotation of the rotatable member 30 (i.e., the rotatable member 30 has rotated for a second portion of the period T) will move the pin 32 out of the sliding path of the slider 12. The potential energy stored in the spring 14 will be released in the form of kinetic energy of the driven staple, thereby driving the staple into the article. Then, at step 105, after the staple is ejected, the user manually releases the trigger switch 62. However, because the internal switch 64 remains in the closed position when the cam follower 50 engages the second surface 44 during the remaining period, the pin 32 is further rotated by the rotatable member 30 at step 106. At the same time, at step 107, the pin 32 engages the slider 12 and compresses the spring 14 to store potential energy. Eventually, due to the rotation of the rotatable member 30, the cam follower 50 will reach the stepped surface 45, i.e. the rotatable member 30 has rotated for a third portion of the period T, so that the internal switch 64 will be immediately depressed to deactivate the motor 20, step 108. Thus, the drive mechanism 10 is self-locking in the locked position and ready to operate in the next firing cycle T.

When the motor 20 is deactivated, the rotatable member 30 and the pin 32 disposed thereon may continue to rotate due to inertia. The pin 32 will engage the receiving portion 80 and compress the spring 14. The spring 14 will apply a biasing force F to the pin 32 through the wedge slot 90.

Referring finally to the free body view of the pin 32 in FIG. 7, the two

inclined surfaces

92, 94 will each exert a force F on the pin 32 at a predetermined angle ₁ 、F ₂ . These two forces F ₁ 、F ₂ Will be resolved into two horizontal forces F acting on the pin 32 from the same direction _1N 、F _2N And two vertical forces F acting on the pin 32 from opposite directions _1V 、F _2V . Thus, the two opposing forces F _1V 、F _2V The pin 32 will be held in place and the pin 32 will remain stationary.

The next operating cycle T can be restarted by the user pressing the trigger switch 62, repeating steps 101 to 108. It should be noted that the time slots illustrated in fig. 6 do not refer to any particular length of time period, but rather this is entirely dependent on the actions of the user. Once the user again presses the trigger switch 62, the next cycle begins, starting again with step 101.

Those skilled in the art will appreciate that in the foregoing description and in the appended claims, positional terms such as "front", "back", "top", "bottom", "above", "below", "upper", "lower", "lateral", "vertical", "forward", etc., are described with reference to conceptual illustrations of an electronic binder, such as those used normally and/or shown in the accompanying drawings. These terms are used for ease of reference and are not intended to be limiting in nature. Accordingly, these terms should be understood to refer to the electronic binder as it is oriented in the figures.

While the present invention has been described in terms of the preferred embodiments described above, it should be understood that these embodiments are illustrative only, and the claims are not limited to these embodiments. Those skilled in the art will be able to make modifications and substitutions in accordance with the present invention which are considered to be within the scope of the appended claims. Each feature disclosed or illustrated in this specification may be incorporated in the invention, alone or in any suitable combination with any other feature disclosed or illustrated herein.

Claims

1. A power tool (1) comprising:

a drive mechanism (10) for driving a fastener into an article,

a motor (20) adapted to actuate the drive mechanism (10),

a rotatable member (30) rotatable by the motor (20), and

the first switch (62) is normally biased to an open position and when a user of the power tool (1) depresses the first switch (62), the first switch is turned to a closed position to energize the motor (20),

the second switch (64) is normally biased to an open position and is adapted to be turned to a closed position to energize the motor (20) when the first switch (62) is in its open position.

2. The power tool (1) according to claim 1, wherein the second switch (64) is actuated by the rotatable member (30) to energize the motor (20) when the first switch (62) is in its off position.

3. The power tool (1) according to claim 2, wherein the rotatable member (30) comprises a cam (40) and the second switch (64) is triggered by a cam follower (50) of the cam (40).

4. The power tool (1) according to claim 3, wherein the cam (40) comprises a first surface (42) and a second surface (44); the second switch (64) remains biased to an open position during engagement of the cam follower (50) and the first surface (42); during engagement of the cam follower (50) and the second surface (44), the second switch (64) is rotated to the closed position to energize the motor (20).

5. A power tool (1) according to claim 4, wherein the transition from the first surface (42) to the second surface (44) in the first rotational direction is in a gradual manner such that the second switch (64) switches from the open position to the closed position when the rotatable member (30) has rotated a first portion of a predetermined period.

6. A power tool (1) according to claim 4 or 5, wherein the transition from the first surface (42) to the second surface (44) in the second rotational direction is in a stepwise manner such that the second switch (64) switches from the closed position to the open position when the rotatable member (30) has rotated a second portion of the predetermined period.

7. A power tool (1) according to claim 3, wherein the second switch (64) is triggered by a tilting movement of the cam follower (50).

8. The power tool (1) according to claim 7, wherein the cam follower (50) is provided as a lever by which a pressing force exerted by the cam (40) on the second switch (64) is amplified.

9. The power tool (1) according to claim 8, wherein the lever is pivotable about a fulcrum (52).

10. The power tool (1) according to claim 9, wherein the second switch (64) is spaced from the fulcrum (52) by a distance L1, the cam (40) is spaced from the fulcrum (52) by a distance L2, L2 being different from L1.

11. The power tool (1) according to claim 1, wherein the power tool (1) is an electric stapler.

12. A power tool (1) comprising:

a motor (20) for actuating the drive mechanism (10), and

a rotatable member (30) rotatable about a rotation axis (31) by the motor (20),

a locking mechanism (70) for locking the rotatable member (30) in a locked position when the motor (20) is deactivated by the operating mechanism (60),

wherein the locking mechanism (70) comprises a female member, a biasing means (14) and a male member adapted to engage the female member and resist the biasing means (14) during engagement such that the rotatable member (30) is balanced in the locked position.

13. The power tool (1) according to claim 12, wherein the female member is mounted to the drive mechanism (10) and the male member comprises a pin (32), the pin (32) being mounted on the rotatable member (30) to move in a circumferential direction, the female member being adapted to prevent the pin (32) from moving during engagement.

14. The power tool (1) according to claim 13, wherein the female member includes a receiving portion (80) biased to move against the pin (32) to lock the pin (32) against further movement of the pin (32) when the motor (20) is deactivated by the operating mechanism (60).

15. The power tool (1) according to claim 14, wherein the receiving portion (80) comprises a profile substantially complementary to the shape of the pin (32).

16. The power tool (1) according to claim 15, wherein the receiving portion (80) comprises a wedge-shaped slot (90) for receiving the pin (32) when the motor (20) is deactivated.

17. The power tool (1) according to claim 16, wherein the wedge-shaped groove (90) is formed by two inclined surfaces (92, 94), one of which is arranged at a predetermined angle (a) to the other.

18. The power tool (1) according to claim 17, wherein each of the two inclined surfaces (92, 94) applies two opposing forces to the pin (32) to hold the pin (32) in place.

19. The power tool (1) according to claim 17, wherein the two inclined surfaces (92, 94) are arranged at different inclinations.

20. The power tool (1) according to claim 12, wherein the power tool (1) is an electric stapler.