Switch assembly, switch assembly control method and electric tool

Abstract

A switch assembly control method, the switch assembly comprising: a housing, a main switch housed in the housing, and a safety lock and a trigger mounted on the housing, the safety lock being movable between a locked position and an unlocked position and blocking the trigger when in the unlocked position such that the main switch is not turned on; when the safety lock is located at the locking position, when the trigger is triggered and moves through a first stroke, the main switch starts a'keep-run 'mode; and when the trigger moves through the second stroke, the main switch enables a constant mode.

Description

Technical Field

[0001] The present invention relates to an electric tool, and in particular to a switch component for the electric tool, a control method of the switch component, and an electric tool having the switch component. Background Art

[0002] Users can operate power tools, especially heat tools (e.g., heat guns), in two different modes depending on the application. One mode is a "keep-on" mode: if the enabling switch (or trigger) is pressed, the tool will start, and when the enabling switch is released, the tool will turn off. This mode is suitable when the tool is used for a short period of time. The other mode is a "constant" mode: if the user performs a certain action (e.g., locks the enabling switch (or trigger)), the tool will keep running in continuous operation. This mode is suitable for hands-free use or when the tool is used for a long time. Without the "constant" mode, hands-free operation cannot be achieved. This will limit the application of heat tools.

[0003] To meet the demand for power tools to implement both modes described above, existing solutions typically rely on additional control elements such as a trigger lock (as known in hobby drills) or even an additional locking device. However, the additional control element only locks the "keep running" enabling switch in the on position. Mechanical control elements need to be operated to switch from one operating mode to the other, which adds additional cost and effort. Moreover, in dusty job site conditions, the additional parts and required movements may cause malfunctions and may result in hazardous situations. In addition, in most cases, existing solutions are optimized only for right-handed users; this involves ergonomic issues, thereby limiting equal use by left-handed and right-handed users.

[0004] In view of the above situation, it is necessary to improve the existing switch assembly and the electric tool assembled with the switch assembly so as to solve the above problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a switch assembly for an electric tool, a control method of the switch assembly, and an electric tool having the switch assembly, so as to control two operating modes in a simple and reliable manner and prevent accidental switching on.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] A control method for a switch assembly for an electric tool, the switch assembly being connected to an electronic control unit of the electric tool, the switch assembly comprising a main switch housed in a housing of the electric tool, and further comprising a safety lock and a trigger mounted on the housing, the safety lock being movable between a locked position and an unlocked position, and the safety lock blocking the trigger when in the locked position so that the main switch is not turned on; when the safety lock is in the unlocked position, when the trigger is triggered and moves through a first stroke, the main switch enables a "keep-on" mode; and when the trigger moves through a second stroke, the main switch enables a "constant" mode. Therefore, by combining the switch assembly and the two operating modes "keep-on" and "constant" and by controlling the triggering and moving stroke of the trigger, the present invention achieves switching between the two operating modes in a simple and reliable manner, and the safety lock prevents accidental activation.

[0008] According to an embodiment of the present invention, when the main switch enables the "keep-run" mode, the safety lock remains in the unlocked position and the trigger remains in the position where it has moved within the first stroke; when the trigger is released, the main switch is disconnected and the power tool stops working. Therefore, in the "keep-run" mode, it is necessary to press the trigger continuously; if the trigger is released, the main switch is immediately disconnected.

[0009] According to an embodiment of the present invention, when the main switch enables the "constant" mode, the trigger is released back to its initial position and the safety lock moves back to the locked position. In the "constant" mode, the user does not need to continue to hold the power tool, and the power tool remains in a hands-free state, which greatly improves the convenience of operation.

[0010] According to an embodiment of the present invention, if the trigger is triggered again and moves through the third stroke, the main switch is disconnected, thereby ending the "constant" mode. If the power tool is running in the "constant" mode, the user needs to press the trigger again to turn off the power tool. In order to avoid having to press the safety lock to turn off the tool, a certain travel distance (third stroke) is left between the trigger and the safety lock, so there is no need to press the safety lock. This travel distance is only used to turn off the "constant" mode of the tool.

[0011] According to an embodiment of the invention, the main switch is designed as a potentiometer with discrete or continuous travel distances, the travel distances of the potentiometer corresponding to the first, second and / or third travels of the movement of the trigger, and the electronic control unit calculates and determines the activation and switching of the tool operating mode with the aid of the signal of the potentiometer. With this configuration, it is possible to implement at least 2 operating modes ("keep running" and "constant") by assigning these operating modes to certain trigger positions without the need for additional control components, thereby reducing sensitivity to dust / dirt.

[0012] According to an embodiment of the present invention, the first stroke is smaller than the second stroke; and the third stroke is smaller than the first stroke. Different operation modes are switched by evaluating different stroke distances of the trigger movement.

[0013] According to an embodiment of the present invention, when the trigger moves through the first stroke, a feedback signal is provided to identify that the main switch is switching from the "keep running" mode to the "constant" mode. The feedback signal includes any one or a combination of a tactile signal, an auditory signal or a visual signal. The feedback signal helps the user to identify the switching of the operation mode to avoid erroneous operation.

[0014] The present invention also provides a switch assembly for an electric tool, which is connected to an electronic control unit of the electric tool and includes a main switch housed in a housing of the electric tool, and further includes a safety lock and a trigger mounted on the housing, and the switch assembly is designed to execute the above-mentioned switch assembly control method.

[0015] According to an embodiment of the present invention, the safety lock is installed on the rear side of the housing, and the installation lock includes: a pressing part exposed above the housing, a resisting part resisting the trigger, and a rotating part connecting the pressing part and the resisting part.

[0016] According to an embodiment of the present invention, when the safety lock is in the locked position, the contact portion of the resisting portion and the trigger has a gap of the maximum distance of the third stroke. If the tool is operated in the "constant" mode, the user needs to press the trigger again to close the tool. In order to avoid having to press the safety lock to close the tool, a certain moving distance is left between the trigger and the safety lock, so there is no need to press the safety lock. This moving distance (i.e. the distance of the third stroke) is only used to close the "constant" mode of the tool. Within this stroke distance, the tool is not allowed to open because the safety lock does not cover this stroke distance. According to an embodiment of the present invention, an additional force step is provided between the main switch and the trigger, and the spring is compressed when the trigger moves through the first stroke, and a pressure greater than the pressure of the first stroke is required to make the trigger move further through the second stroke. In order to enable the user to identify the trigger stroke distance, and thereby enable the user to distinguish between the two operating modes, an additional identifiable force step (e.g., an additional spring on the switch lever) is used. The additional force step should be engaged at the same trigger stroke distance that triggers the constant mode, and this gives the user tactile feedback.

[0017] According to another embodiment of the present invention, a sensor for detecting the distance the trigger moves is provided between the main switch and the trigger, and when the trigger moves through a first stroke, the sensor sends a signal to the electronic control unit of the power tool to recognize that the main switch is switching from the "keep running" mode to the "constant" mode. In this way, the sensor can recognize the change between the two modes and can provide the user with audible (click or buzz) or visual (flash, light, indicator light) feedback.

[0018] In addition, the present invention further provides an electric tool, which includes the above switch assembly and an electronic control unit connected to the switch assembly to control the power tool to be turned on or off. The two operating modes of the power tool - "keep running" and "constant" - are achieved by the above switch assembly control method.

[0019] The power tool is a thermal tool, in particular a thermal gun. Certain specific application scenarios of thermal tools (especially thermal guns) require continuous operation. In these cases, the hands-free function is particularly important; the thermal tool is fixed to a support, the "constant" mode is enabled, and the tool is continuously operated without the user holding it in the hand, thus greatly increasing the application scenarios and convenience of the thermal tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The embodiments described herein will be better understood by the following detailed description when reading the accompanying drawings. It should be emphasized that the components are not necessarily drawn to scale. In fact, the dimensions may be arbitrarily enlarged or reduced for clarity of discussion. In the accompanying drawings, the same reference numerals refer to the same elements.

[0021] Figure 1 A schematic diagram of a switch assembly according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0022] The following references Figure 1 A switch assembly for an electric tool, a switch assembly control method, and an electric tool having the switch assembly according to embodiments of the present invention are described.

[0023] The electric tool of the present invention can be a hot tool, a blower, etc., and in particular can be a hot gun, but is not limited to a hot tool. As an exemplary embodiment of the present invention, the electric tool is a hot gun. The hot gun includes a housing, a heating unit, a fan unit, a battery unit, an electronic control unit and a switch assembly 10. An air outlet for discharging heated air is provided at one end of the housing. The fan unit has an electric motor and at least one fan blade that can be driven by the electric motor. The airflow generated by the fan unit is heated by the heating unit. The control unit implements appropriate control of the heating unit and the fan unit. The battery unit is mounted to the bottom of the housing 11 in a known manner. The switch assembly 10 is used to turn the electric tool on or off. In view of the fact that other units or components of the electric tool of the present invention are known, the following part of this specification will mainly describe the specific structure and activation method of the switch assembly 10 in detail.

[0024] Figure 1 A partial schematic diagram of a handle portion of a power tool is shown, wherein a switch assembly is mounted to the handle portion. A housing 11 is partially shown as a handle of the power tool. Typically, the switch assembly 10 is mounted on the handle, where the switch assembly can be most conveniently operated. The switch assembly 10 includes a main switch 12 housed in the housing 11, and a safety lock 13 and a trigger 14 mounted on the housing 11.

[0025] The safety lock 13 of the present invention is installed on the rear side of the handle, and the safety lock includes: a pressing portion 131 exposed above the housing 11, a resisting portion 132 contacting (resisting) the trigger 14, and a rotating portion 133 connecting the pressing portion 131 and the resisting portion 132. The pressing portion 131 has a profile that roughly matches the outer surface of the handle, and the pressing portion 131 is exposed outside the housing 11 so that the user can manually press it. The rotating portion 133 is installed on a supporting structure in the housing 11 so that the rotating portion 133 can move and rotate relative to the housing 11; therefore, when the pressing portion 131 is pressed, the resisting portion 132 can be synchronously driven to rotate.

[0026] The safety lock 13 has a locked position and an unlocked position. As long as the pressing portion 131 of the safety lock 13 is not pressed, the safety lock 13 is in the locked position; the safety lock is arranged opposite to the trigger 14 and limits the action of the trigger 14, the trigger 14 is locked, the main switch 12 cannot be turned on, and therefore the power tool cannot be operated, thereby preventing the power tool from being accidentally started. When the user grasps the power tool by the handle, the pressing portion 131 will be naturally pressed, and by this action, the safety lock 13 moves to the unlocked position and no longer obstructs the trigger 14. When the safety lock 13 is in the unlocked position, the safety lock 13 is not located in a position opposite to the trigger 14, and the restrictive relationship between them is released; the trigger 14 is unlocked, the main switch 12 can be turned on, and if the trigger 14 is pressed at this time, the main switch 12 is turned on, the power tool starts to operate, and the power tool performs normal operation.

[0027] It should be noted that when the safety lock 13 is in the locked position, a gap of a certain distance (i.e., the maximum distance of the third stroke of the trigger 14) is left between the blocking portion 132 and the trigger 14, which is used to disconnect the main switch in the "constant" mode of the power tool, thereby turning off the power tool. This function is further described in detail below.

[0028] refer to Figure 1 The main switch 12 includes a body portion 121 and an extension / retraction arm 122 connected to the body portion 121; the extension / retraction arm 122 is configured to be elastic so as to automatically return to its original position when the pressure is released. In one embodiment of the present invention, the main switch 12 is a potentiometer configured to measure and determine the trigger position and movement distance of the trigger 14. Such movement distance measurement can be discrete and / or continuous.

[0029] The trigger 14 includes a trigger portion 141 exposed below the housing 11, a connection portion 142 connected to the main switch 12, and a contact portion 143 that can contact the blocking portion 132 of the safety lock. When not triggered, the trigger 14 is in its initial position; when the user presses the trigger portion 141, when the safety lock 13 is in the unlocked position, the entire trigger 14 moves toward the safety lock.

[0030] Preferably, an additional force step (e.g., a spring) is provided between the main switch 12 and the trigger 14; when the trigger 14 moves through the first stroke, the spring is compressed, and a greater pressure than the pressure in the first stroke is required to move the trigger 14 further through the second stroke. Therefore, when the "keep running" mode is switched to the "constant" mode, the user needs a greater force to press and move the trigger 14, so that the user is aware of the change in the operating mode.

[0031] According to another embodiment of the present invention, a sensor (not shown) for detecting the travel distance of the trigger is provided between the main switch 12 and the trigger 14; when the trigger moves through the first travel, the sensor sends a signal to the electronic control unit of the power tool to identify that the main switch is switching from the "keep running" mode to the "constant" mode. In this way, the sensor can identify the change between the two modes and can provide the user with auditory (e.g., clicks or buzzing) or visual (e.g., flashes, lights, indicator lights) feedback. In other embodiments, the feedback unit can also be integrated into the electronic control unit of the power tool. Alternatively, the sensor can (not necessarily) be the main switch itself, because the main switch is a potentiometer.

[0032] The control method of the switch assembly of the present invention is described in detail below.

[0033] First, when the power tool is not in use, the safety lock 13 is in the locked position; at this time, since the safety lock 13 blocks the trigger 14 and the main switch 12, pressing the trigger 14 cannot move the trigger 14, so the main switch 12 will not be turned on.

[0034] When the user grasps the handle of the power tool, the user can easily press the safety lock 13 to rotate it from the locked position to the unlocked position because the pressing portion 131 of the safety lock is located on the rear side of the handle; the user's finger presses the trigger portion 141 of the trigger 14, and the trigger 14 starts to move; the user continues to press the trigger portion 141 until the trigger 14 has moved through the first stroke (for example, 4 mm), and the extension / retraction arm 122 of the main switch has been pushed by the connecting portion 142 of the trigger and moved through the distance of the first stroke (for example, 4 mm). At this time, the potentiometer as the main switch measures the distance that the extension / retraction arm has moved through the first stroke, and determines that the "keep running" mode is enabled; the power tool starts working, and the power tool starts to operate normally. In the "keep running" operating mode, the user needs to continuously grasp the handle of the power tool, that is, the safety lock 13 is in the unlocked position, and the trigger 14 remains in the position where it has moved within the first stroke. If the trigger 14 is released, the main switch will be disconnected. This mode is suitable when the tool is used for a short period of time, or for scenarios that require the user to perform specific operations.

[0035] However, for thermal tools (especially heat guns), it is sometimes necessary to work on the workpiece for a long time, such as supplying hot air to a frozen pipe for a long time to melt the frozen part. In such applications, the hands-free function is advantageous because it can free the user's hands, thereby reducing the user's labor intensity and fatigue. The implementation of the hands-free function requires the power tool to have a "constant" operating mode: if the user performs a certain action, such as locking the enable switch (or trigger), the tool will enter a state of continuous operation; the user does not need to grasp the power tool to turn off this operating mode, and the power tool will keep running until the user performs another action. This mode is suitable for hands-free use or long-term use of the tool. Without the "constant" mode, hands-free operation cannot be achieved. This will limit the application of thermal tools.

[0036] In order to avoid accidental startup of the power tool (which would create unnecessary danger), the trigger can only be triggered when the safety lock of the power tool is pressed to the unlocked position; therefore, the power tool is always started in the "keep-run" mode first. Once the "keep-run" mode is enabled, if the user wishes to switch to the "constant" mode, the user continues to press the trigger 14 to move it through a second stroke distance (e.g. 8 mm). The control unit measures the distance of this second stroke and determines that the "constant" mode is enabled. The user can then release the trigger 14; the trigger 14 returns to the initial position, but the power tool continues to run. Even if the user no longer grasps the handle and releases the trigger 14 and the safety lock 13 at the same time, the trigger 14 returns to the initial position and the safety lock 13 returns to the locked position, the power tool will continue to run.

[0037] In addition, in order to allow the user to clearly identify when the power tool has switched from the "keep running" mode to the "constant" mode, a feedback signal is provided to the user so that the user knows the mode change when the trigger 14 is pressed through the first stroke (e.g., 4 mm). The feedback signal may be tactile, audible (e.g., a click or buzz) and / or visual (e.g., a flash, light, indicator light), etc. Preferably, as Figure 1 As shown, an additional force stage, such as a spring, is provided between the main control switch 12 and the trigger 14. The spring begins to be compressed at the position where the trigger has moved through the first stroke; due to the resilience of the spring, further moving the trigger to the position of the second stroke will require a greater pressure than the pressure when the trigger is in the first stroke, so the user can directly sense the activation of the "constant" mode by touch.

[0038] When the power tool is operated in the "constant" mode, it is likely to be in a hands-free state, for example, the tool is fixed to a support and performs an operation on a specific workpiece. When the power tool has completed the designated work and needs to be turned off, the user does not need to grab the handle of the tool again, but only needs to lightly touch the trigger 14 to move the trigger 14 through the distance of the third stroke (for example, 2mm); the main switch 12 will be disconnected immediately, and the power tool will stop running. The distance of the third stroke mentioned here refers to the gap distance between the abutment portion 132 of the safety lock 13 and the contact portion 143 of the trigger 14 when the safety lock 13 is in the locked position. Therefore, in the "constant" mode, the user does not need to press the safety lock 13 again to rotate it to the unlocked position, but only needs to press the trigger to move through the third stroke (for example, 2mm) and thereby disconnect the main switch and turn off the power tool in a simple manner. However, if the power tool is not in the "constant" operating mode, if the user presses the trigger and moves the trigger 14 through the third stroke (2mm), the power tool will not be turned on.

[0039] In the present invention, the first stroke, the second stroke or the third stroke through which the trigger 14 moves is set by the potentiometer of the main switch, and different stroke distances can be defined according to the structure and requirements of different power tools; for example, in the above embodiment, the first stroke distance is 4mm, the second stroke distance is 8mm, and the third stroke distance is 2mm. Alternatively, the first stroke distance is 3mm to 5mm, the second stroke distance is 6mm to 8mm, and the third stroke distance is 1.5mm to 2.5mm. In the above embodiment, the path along which the trigger 14 moves is unique, that is, the trigger moves through the first, second or third stroke, in each case the trigger part is pressed, and the trigger 14 moves in a straight line toward the safety lock. Therefore, the first stroke should be less than the distance of the second stroke, and the distance of the third stroke should be less than the distance of the first stroke. Here, any stroke distance is calculated from zero or the initial position.

[0040] According to alternative embodiments, the trigger may alternatively have a different movement path (e.g., trigger rotation direction or trigger movement position), and correspondingly, the first stroke, the second stroke, and the third stroke correspond to the rotational or movement strokes or positions of the trigger, respectively.

[0041] In the switch assembly of the power tool and the control method thereof according to the present invention, and in the power tool having the switch assembly, the switching and control of at least two operating modes ("keep running" and "constant") can be achieved by different strokes of the trigger. No additional mechanical control components are required; the user only needs to grasp the handle to control the position of the safety lock and the trigger, and thereby distinguish and switch between the two operating modes in a visually direct manner, thereby enabling hands-free use. In addition, the convenience of operation is increased when both the left and right hands are available.

[0042] As described above, although the exemplary embodiments of the present invention have been explained herein with reference to the accompanying drawings, the present invention is not limited to the above specific embodiments and may have many other embodiments. The scope of the present invention should be defined by the claims and their equivalents.

Claims

1. A control method for a switch assembly of an electric tool, the switch assembly being connected to an electronic control unit of the electric tool, the switch assembly comprising a main switch housed in a housing of the electric tool, and further comprising a safety lock and a trigger mounted on the housing, the safety lock being movable between a locked position and an unlocked position, and the safety lock blocking the trigger when in the locked position so that the main switch is not turned on, characterized in that When the safety lock is in the unlocked position, when the trigger is triggered and moves through a first stroke, the main switch enables a "keep running" mode; and when the trigger moves through a second stroke, the main switch enables a "constant" mode.

2. The control method of the switch assembly according to claim 1, characterized in that: When the main switch enables the "hold-to-run" mode, the safety lock remains in the unlocked position and the trigger remains in the position it has moved within the first stroke; when the trigger is released, the main switch is disconnected.

3. The control method of the switch assembly according to claim 2, characterized in that: When the master switch enables the "constant" mode, the trigger is released and the safety lock moves back to the locked position.

4. The control method of the switch assembly according to claim 3, characterized in that: If the trigger is triggered again and moves through the third stroke, the main switch is disconnected, thereby ending the "constant" mode.

5. The control method of the switch assembly according to claim 4, characterized in that: The first stroke is smaller than the second stroke; and the third stroke is smaller than the first stroke.

6. The control method of the switch assembly according to any one of claims 1 to 5, characterized in that: The main switch is designed as a potentiometer with discrete and / or continuous value steps which can be measured and processed by the electronic control unit to calculate / determine the switch travel distance to the respective triggering position.

7. The control method of the switch assembly according to claim 6, characterized in that: When the trigger moves through the first stroke, a feedback signal is provided to identify that the main switch is switching from the "keep running" mode to the "constant" mode.

8. The control method of the switch assembly according to claim 7, characterized in that: The feedback signal includes any one or a combination of a tactile signal, an auditory signal or a visual signal.

9. A switch assembly for an electric tool, the switch assembly comprising a main switch housed in a housing of the electric tool, and further comprising a safety lock and a trigger mounted on the housing of the electric tool, the switch assembly being connected to an electronic control unit of the electric tool, the safety lock being movable between a locked position and an unlocked position, and the safety lock blocking the trigger when in the locked position so that the main switch is not turned on, characterized in that: When the safety lock is in the unlocked position, the main switch is configured to enable a "keep running" mode when the trigger is triggered and moves through a first stroke; and the main switch is configured to enable a "constant" mode when the trigger moves through a second stroke.

10. The switch assembly according to claim 9, characterized in that The safety lock is installed on the rear side of the housing, and the installation lock includes: a pressing portion exposed above the housing, a resisting portion resisting the trigger, and a rotating portion connecting the pressing portion and the resisting portion.

11. The switch assembly according to claim 10, characterized in that When the safety lock is in the locked position, the blocking portion and the other end of the trigger have a gap of a maximum distance of the third stroke.

12. The switch assembly according to claim 11, characterized in that An additional spring is provided between the main switch and the trigger, which is compressed when the trigger moves through the first stroke and requires a pressure greater than the pressure in the first stroke to move the trigger further through the second stroke.

13. The switch assembly according to claim 11, characterized in that A sensor for detecting the movement distance of the trigger is provided between the main switch and the trigger, and when the trigger moves through the first stroke, the sensor sends a signal to the electronic control unit of the power tool to recognize that the main switch is switching from the "keep running" mode to the "constant" mode.

14. An electric tool, characterized in that: The electric tool comprises a switch assembly according to any one of claims 9 to 12 and an electronic control unit connected to the switch assembly to control the power tool to be turned on or off.

15. The electric tool according to claim 14, characterized in that: The power tool is a heat tool, in particular a heat gun.

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