Power Impact Tool Trigger Control Circuit
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Solution Overview
Problem
Existing power impact tools require users to repeatedly depress the trigger and lock it in position for continuous hammering operations, making the process cumbersome and inefficient.
Innovation Solution
The power impact tool incorporates a control circuit and mechanism that allows continuous hammering without needing to keep the trigger depressed, using a semiconductor switch controlled by a controller that energizes the motor based on trigger position and mode switching, enabling easy operation and reduced vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the trigger is locked in the operating position by the engaging member to enable continuous hammering operation, then the tool bit can perform continuous striking movement without repeatedly operating the trigger, but the device complexity increases due to the additional engaging member and locking mechanism
Solution Approach 1:
The patent removes the engaging member and trigger locking mechanism from the device, eliminating the complexity associated with these components while maintaining continuous operation capability through alternative means
Solution Approach 2:
The patent replaces the mechanical trigger locking system with an electrical control system that uses a semiconductor switch and controller to maintain motor operation without requiring mechanical trigger retention, thereby simplifying the mechanical structure
2Device complexity
If the trigger is depressed continuously to maintain hammering operation, then the operation is simple without additional locking mechanisms, but the ease of operation deteriorates due to the need for constant trigger depression
Solution Approach 1:
The patent replaces the continuous mechanical trigger depression requirement with an electrical latching system using a semiconductor switch controlled by a controller, which maintains motor operation without requiring continuous physical trigger pressure
Solution Approach 2:
The controller automatically maintains the semiconductor switch in the on-state after initial trigger activation, allowing the system to sustain operation autonomously without requiring continuous user input or trigger depression
3Productivity
If the engaging member is used to lock the trigger in the operating position, then continuous hammering can be achieved, but the ease of operation worsens due to the need to operate both the trigger and the engaging member
Solution Approach 1:
The patent removes the engaging member entirely from the device, eliminating the need to operate both the trigger and the engaging member, while maintaining continuous operation capability through the electrical control system
Solution Approach 2:
The patent replaces the dual-operation mechanical system (trigger plus engaging member) with a simplified electrical control system that requires only initial trigger activation to sustain continuous motor operation
Data Source
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AI summary
The object of the invention is to ease of operation of the power impact tool. Such object is achieved by a representative power impact tool (101) according to the invention including a motor (111), a tool bit (119), a trigger (137) and a mode changing member (133). The trigger (137) is manually operated by a user to control energization and non-energization of current to drive the motor (111). The motor (111) is energized when the user operates the trigger (137) to turn on and the energized state of the motor (111) is maintained until the trigger (137) is again operated in a same manner with the turning-on operation. According to the invention, once the trigger (137) is depressed from the initial position to the operating position, a hammering operation can be performed by the striking movement of the tool bit (119) without the need to lock the trigger (137) in the operating position. Therefore, ease of operation of the hammer drill (101) is enhanced.