Switch for power tools

Abstract

The invention relates to a hand-held power tool (10) comprising a main body (12) and an electric motor (50) mounted in the main body (12), a switch (40) mounted in the main body (12) and delivering power to the motor (50) when activated, a first actuator (20) mounted in the main body (12) and engaged by a user to be moved by the user from a first position to a second position, a second actuator (220) mounted in the main body (12) and engaged by a user to be moved by the user from a first position to a second position, and a motion transmission device (30) engageable with both actuators to actuate the switch when both actuators are in the second position.

Description

TECHNICAL FIELD

[0001] The present invention relates to a switch for a power tool. BACKGROUND

[0002] Safety features of power tools are important to ensure that users of such power tools are not injured. For example, power tools with sharp cutting blades can have guards over the blades to protect the user in the event of accidental activation. Another way to improve the safety of power tools is to ensure that accidental activation does not occur, or at least to minimise the likelihood of accidental activation.

[0003] It is an object of the present invention to improve the safety of power tools. SUMMARY

[0004] In one aspect, there is provided a hand-held power tool comprising:

[0005] a body;

[0006] an electric motor mounted within the body;

[0007] a switch mounted within the body and which delivers electrical power to the motor when activated;

[0008] a first actuator mounted in the body and engaged by a user to be moved by the user from a first position to a second position;

[0009] a second actuator mounted in the body and engaged by a user to be moved by the user from a first position to a second position; and

[0010] a motion transmission device engageable by both actuators to actuate the switch when both actuators are in the second position.

[0011] Preferably, when both the first actuator and the second actuator are engaged by the user and moved from the first position to the second position, the motion transmission device moves linearly to actuate the switch.

[0012] Preferably, when only the first actuator or the second actuator is engaged by the user and moved from the first position to the second position, the motion transmission device moves angularly and does not actuate the switch.

[0013] Preferably, the switch is connected directly or indirectly to the electric motor.

[0014] Preferably, the motion transmission device comprises:

[0015] a first contact surface which the first actuator contacts when the first actuator is engaged by the user;

[0016] a second contact surface which is contacted by the second actuator when the second actuator is engaged by a user; and

[0017] a pivot and a translation point between the first and second contact surfaces.

[0018] Preferably, the motion transmission device is movably coupled to the first and second actuators.

[0019] Preferably, the motion transmission device is pivotally attached to only one of the first or second actuators.

[0020] Preferably, the motion transmission device is cam-shaped to actuate the switch when both actuators are in the second position.

[0021] Preferably, the first actuator is pivotally mounted in the body and the second actuator is slidably mounted in the body.

[0022] Preferably, the first actuator has a maximum travel which does not actuate the switch when the first actuator is in the second position.

[0023] Preferably, the second actuator has a maximum travel which does not actuate the switch when the second actuator is in the second position. BRIEF DESCRIPTION OF DRAWINGS

[0024] A preferred embodiment of the present application will be described by way of example only with reference to the accompanying drawings in which:

[0025] Figure 1 is a cross-sectional view of a hand-held power tool according to the first embodiment with the motion transmission device in the first position;

[0026] Figure 2 is Figure 1 is an enlarged view of the power tool shown, specifically showing the motion transmission device and the switch;

[0027] Figure 3 is Figure 1 is a cross-sectional view of the hand-held power tool shown with the first actuator engaged;

[0028] Figure 4 is Figure 1 is a cross-sectional view of the hand-held power tool shown with the second actuator engaged; and

[0029] Figure 5 is a cross-sectional view of the hand-held power tool shown with both the first actuator and the second actuator engaged. Figure 1

[0030] Figure 6 is a schematic view of a switch and a motion transmission device according to the second embodiment.

[0031] ​Figure 7A and Figure 7B is a schematic view of a switch and motion transmission device according to a third embodiment.

[0032] Figure 8 is a schematic view of a switch and motion transmission device according to a fourth embodiment. DETAILED DESCRIPTION

[0033] Figures 1 to 5 A hand-held power tool 10 according to a preferred embodiment is shown. In the example of a hedge trimmer, the hand-held power tool 10 has a main body 12, a rear handle 13 and a pommel handle 15. The handles 13 and 15 are integral with the main body 12. Figures 1 to 5

[0034] The rear handle 13 has a first actuator 20 mounted in the main body 12. The first actuator 20 is pivotable about a pin 17. The pommel handle 15 has a second actuator 22 also mounted in the main body 12, as shown in Figures 1 to 5 . The second actuator 22 is pivotable about a pin 18. Each of the actuators 20 and 22 is engageable by a user to be moved by the user from a first position to a second position. The first position of the actuators 20 and 22 is shown in Figure 1 . The second position of the actuator 20 is shown in Figure 3 and Figure 5 . The second position of the actuator 22 is shown in Figure 4 and 5 . Each actuator 20 and 22 has a portion 21 and 23, respectively. The portions 21 and 23 protrude from each actuator member 20 and 22. In the example embodiment shown, the portions 21 and 23 are narrower than the actuator members 20 and 22. Each portion 21 and 23 has a corresponding contact surface 24 and 25, respectively. Figures 1 to 5

[0035] The switch 40 is mounted in the main body 12 of the power tool 10 using fastening means such as screws, or can be secured by pins (not numbered). The switch 40 has a pressable contact 41, as shown in Figure 2 ​​The switch 40 is in direct connection to the electric motor 50 and can activate the electric motor 50. It is also conceivable that the switch 40 can be indirectly connected to the electric motor 50 through a relay (not shown) or the like. The switch 40 is in the form of a mechanical switch and is preferably a push button switch or a spring biased switch that can return to a rest or non-activated position once the user's pressure is removed. Other mechanical switches can also be used, such as a single throw or toggle switch. The switch 40 is independent of the handles 13 and 15 and also independent of the actuating members 20 and 22. This means that the switch 40 remains stationary within (or relative to) the body 12 and also stationary relative to the actuators 20 and 22. The actuators 20 and 22 move relative to the body 12 and also move relative to the switch 40.

[0036] The motion transfer device 30 is also mounted in the body 12 of the power tool 10 and is used to engage the switch 40. The motion transfer device 30 can pivot or angularly move about the pin 31 as shown in Figure 3 and 4 The motion transfer device 30 can also linearly slide or translate along the axis XX of the pin 31 so that the motion transfer device 30 can move towards and away from the switch 30 as shown in Figure 1 , 2 and 5. In the example embodiment, the contact 41 of the single throw or toggle switch 40 pushes the motion transfer device 30 away when the user releases the actuators 20 and 22. As shown in Figure 2 The motion transfer device 30 also has contact surfaces 33 and 32.

[0037] In other arrangements, another mechanism can be used to ensure that the handles 13 and 15 must be engaged to actuate the switch. For example, the motion transfer device can be triangular in shape rather than having an oval shape with protruding contact surfaces 32 and 33.

[0038] The operation of this arrangement will now be described.

[0039] To operate the hand held power tool 10, the user must hold both the rear handle 13 and the saddle handle 15 of the power tool 10. In this case, the operator is then able to engage both actuators 20 and 22 by squeezing each of the actuators 20 and 22 towards the respective handle. The actuators 20 and 22 are both moved from a first position as shown in Figure 1 to a second position as shown in Figure 5 When the user engages the actuators 20 and 22, the actuators 20 and 22 are moved from a first position as shown in Figure 1 to a second position as shown in Figure 5 about the pins 17 and 18. Figure 1 and Figure 5It is shown that, due to the first actuator 20 and the second actuator 22 being engaged, the motion transfer device 30 has linearly translated towards the switch 40 and is pressed into the contact 41. By engaging both actuators 20 and 22, the user creates contact between the portions 21 and 23. In particular, contact is created between the contact surfaces 24 and 25 and the contact surfaces 33 and 32 of the motion transfer device 30, thereby translating the motion transfer device 30 along the axis XX of the pin 31 and towards the switch 40. Then, the motion transfer device 30 presses the contact 41 of the switch 40, thereby actuating the switch 40 and subsequently the electric motor 50. Thus, Figure 1 It is shown that the motion transfer device 30 is in the inactive (or first) position, Figure 5 It is shown that the motion transfer device 30 is in the active (or second) position.

[0040] However, if the user engages only the first actuator 20 as shown, Figure 3 the first portion 21 will contact the surface 32 of the motion transfer device 30, while the second portion 23 will not contact the surface 33 of the motion transfer device 30. In the case of engaging only the first actuator 20, the motion transfer device 30 moves angularly and does not actuate the switch 40. The motion transfer device 30 tilts or moves angularly around the contact 41 of the switch 40, the power tool 10 will not work.

[0041] Similarly, if the user engages only the second actuator 22 as shown, Figure 4 the second portion 22 will contact the surface 33 of the motion transfer device 30, while the first portion 21 will not contact the surface 32 of the motion transfer device 30. In the case of engaging only the second actuator 22, the motion transfer device 30 moves angularly and does not actuate the switch 40. The motion transfer device 30 tilts or moves angularly around the contact 41 of the switch 40, the power tool 10 will not work. In other words, when only the first actuator 20 or the second actuator 22 is engaged, the motion transfer device 30 moves angularly and does not actuate the switch 40 by pushing the contact 41 into the switch 40. The switch 40 is actuated by rotating the motion transfer device 30 around the pin 31 by an arc of a certain degree.

[0042] As mentioned above, the power tool 10 requires both actuators 20 and 22 to be engaged to linearly move or translate the motion transfer device 30 from the first position to the second position to actuate the switch 40. Because this requires the user to use both hands, the likelihood of the power tool 10 being accidentally activated is reduced.

[0043] Actuators 20 and 22 can move independently of switch 40 and are not directly coupled to switch 40. Movement of switch 40 within body 12 is not required to operate motor 50, which means that assembly and disassembly of power tool 10 can be simpler, especially when components need to be repaired or replaced.

[0044] Figures 1 to 5 The example shown is of a preferred embodiment. Other embodiments can be used. For example, instead of a T-shaped motion transfer device, the motion transfer device can have a different shape, such as a triangle, and still be linearly translated to its second position by actuators 20 and 22.

[0045] In another form, the shape of the actuators can be different. For example, the actuators can have a tapered end instead of an actuator having a portion that narrows down to a narrower portion than the rest of the actuator. This tapered end can then be used to engage the motion transfer device.

[0046] In another alternative form, magnets can be used instead of actuators that physically contact the motion transfer device. It is contemplated that first portion 21 of first actuator 20 and contact surface 32 of motion transfer device 30 are attached with magnets of the same polarity. Similarly, second portion 23 of second actuator 22 and contact surface 33 of motion transfer device 30 are attached with magnets of the same polarity. In this configuration, when a user engages actuators 20 and 22, the opposing magnetic forces will linearly urge the motion transfer device into engagement with switch 40 without actuators 20 and 22 contacting motion transfer device 30.

[0047] A second embodiment of a switch and motion transfer device is shown in Figure 6As shown in the figure. Switch 400 is mounted in the body 12 of power tool 10 in the same manner as in the first embodiment described above. Switch 400 has a contact 410, and motion transmission device 300 is placed on or just above the contact 410. Motion transmission device 300 has a first end 320 and a second end 330. The first end 320 and the second end 330 each have a respective pivot 310 and 311, each pivot 310, 311 being movably connected to a respective first actuator 200 and second actuator 220. In use, when the user engages the first actuator 200 and the second actuator 220, motion transmission device 300 moves and presses the switch contact 410, thereby actuating switch 400. If only one of the actuators 200, 220 is engaged, motion transmission device 300 moves at an angle about the switch contact 410 and does not actuate switch 400. By engaging only one of the actuators 200 and 220, the end 320 or 330 movably coupled to the unengaged actuator is lifted, while the engaged end 320 or 330 moves downward. This is achieved because the surface of the contact switch contact 410 of the motion transmission device 300 is smooth, allowing the motion transmission device 300 to slide on the contact 410.

[0048] The third embodiment of the switch and motion transmission device is in Figure 7A and 7B As shown. Switch 400' is mounted in the body 12 of power tool 10 in the same manner as in the first embodiment described above. Switch 400' has contact 410', on which motion transmission device 300' is placed. Figure 7A As shown, the motion transmission device 300' has an end 301' positioned on or above the contact 410'. The end 301' may be inclined, curved, or arc-shaped. The motion transmission device 300' has another end 302' that is pivotally attached to the actuator 200'. Figure 7A and 7B As shown, the motion transmission device 300' is pivotally attached to only one actuator, namely actuator 200'. Actuator 200' is restricted to movement only in the horizontal direction relative to switch 400'. When the user engages actuator 200', the arcuate end 301' slides on contact 410', but cannot actuate switch 400' on its own. Figure 7A As shown, due to the shape of end 301', the motion transmission device 300' is lifted on contact 410'. To actuate switch 400', the user must also engage actuator 220'. When actuator 220' is engaged, end 221' pushes end 301' into contact 410', thereby actuating switch 400'. Figure 7BAs shown, when the actuator 200' is engaged, the end 301' of the motion transfer device 300' pushing the contact 410' is closer to the pivot 302' than when the actuator 200' is not engaged. The actuator 220' is limited to move only in the vertical direction relative to the switch 400'. And the maximum travel of the actuator 220' does not actuate the switch 400'.

[0049] A fourth embodiment of a switch and motion transfer device is shown in Figure 8 The switch 400" is mounted in the main body 12 of the power tool 10 in the same manner as the first embodiment described above. A first actuator 200" associated with a handle (not shown) of the power tool has an end 201". The first actuator 200" is mounted in the main body 12 and is pivotable about a pin 202". The fourth embodiment also has a motion transfer device 300" mounted in the main body 12 and pivotable about a pin 311". The motion transfer device has a first end 301" and a second end 302". A second actuator 220" is also provided, which is slidably mounted in the main body 12 and has a first end 221" and a second end 222". The second actuator 220" is slidable along a track 223". To actuate the switch 400", the user engages the first actuator 200" pivoted about 202", thereby causing the end 201" to contact the end 301" of the motion transfer device 300". The motion transfer device 300" is then pivoted about 311", causing the second end 302" to contact the end 221" of the second trigger 220". The user must also engage the second actuator 220" by sliding the trigger 220" toward the motion transfer device 300". In this way, the end 221" presses on the switch contact 410", thereby actuating the switch 400". Because the motion transfer device 300" is cam-shaped, actuation is achieved. From Figure 8 It is apparent that the switch 400" cannot be actuated unless the user engages both actuators 200" and 220". Because of the angled end 221", the maximum travel of the actuator 220" does not actuate the switch 400". Also, the travel of the actuator 200" is limited, and the maximum travel of the actuator 200" cannot actuate the switch 400" by itself.

Claims

1. A hand-held power tool comprising: a body; a power motor mounted within the body; a switch mounted within the body and delivering power to the motor when activated; a first actuator mounted in the body and engaged by a user to be moved from a first position to a second position by the user; a second actuator mounted in the body and engaged by a user to be moved from a first position to a second position by the user; and a motion transfer device to actuate the switch when both actuators are in the second position, the motion transfer device being mounted within the body independently of the first and second actuators and being engageable by both actuators and being linearly moved to actuate the switch when both the first and second actuators are engaged by the user and moved from the first position to the second position, the motion transfer device being angularly moved and not actuating the switch when only the first or second actuators are engaged by the user and moved from the first position to the second position. the switch being directly or indirectly connected to the power motor.

2. The hand-held power tool of claim 1, characterized by the motion transfer device comprising:

3. The hand-held power tool of claim 2, characterized by a first contact surface, the first actuator contacting the first contact surface when engaged by the user; a second contact surface, the second actuator contacting the second contact surface when engaged by the user; and a pivot and translation point between the first and second contact surfaces. the motion transfer device being movably coupled to the first and second actuators.

4. The hand-held power tool of claim 2, wherein, the motion transfer device being pivotally attached to only one of the first or second actuators.

5. The hand-held power tool of claim 2, wherein, the motion transfer device being cam-shaped to actuate the switch when both of the actuators are in the second position.

6. The hand-held power tool of claim 5, characterized by the first actuator being pivotally mounted in the body and the second actuator being slidably mounted in the body.

7. The hand-held power tool of claim 2, wherein, the first actuator having a maximum travel that does not actuate the switch when the first actuator is in the second position.

8. The hand-held power tool of claim 7, characterized by the second actuator having a maximum travel that does not actuate the switch when the second actuator is in the second position.

9. The hand-held power tool of claim 8, characterized by ​

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