Rotary Hammer Trigger Locking for Continuous Hammer-Only Use
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Solution Overview
Problem
Existing rotary hammers require manual continuous activation of the trigger in hammer only mode, which can be tiring for users.
Innovation Solution
A rotary hammer with a lock-on mechanism that allows the trigger to be locked in the depressed position, enabling continuous motor activation in hammer only mode, and a mode selection dial for switching between hammering and rotational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lock mechanism is added to enable continuous trigger activation, then user convenience and operational efficiency are improved, but device complexity increases
Solution Approach 1:
The lock-on mechanism is nested within the existing trigger assembly structure. The shuttle member is received within the trigger guard, and the spring-loaded plunger is integrated into the trigger mechanism itself. This nesting approach allows the lock-on functionality to be added without requiring a separate, bulky external mechanism, thereby improving ease of operation while minimizing the increase in device complexity.
Solution Approach 2:
The lock-on mechanism is designed to be self-actuating through the spring-loaded plunger that automatically engages with the shuttle member when the trigger is depressed to the locked position. The spring automatically provides the locking force without requiring additional actuators or complex control systems. This self-service approach enables continuous operation functionality while keeping the mechanism relatively simple and maintenance-free.
2Reliability
If mode-specific trigger control is implemented, then operational precision and safety are improved, but device complexity increases
Solution Approach 1:
The mode selection dial is positioned and configured to allow users to select the desired operating mode (hammer-only, chisel, or rotary hammer) before initiating trigger operation. The linkage mechanism is pre-configured to automatically establish the appropriate trigger control mode based on the dial position. This preliminary action ensures that the correct control regime is in place before operation begins, improving reliability while avoiding the need for complex real-time switching mechanisms during operation.
Solution Approach 2:
The linkage mechanism serves as an intermediary between the mode selection dial and the trigger assembly. It translates the dial position into the appropriate trigger control mode by mechanically connecting or disconnecting the trigger from the motor control system based on the selected mode. This intermediary approach provides clean, reliable mode-specific control without requiring complex electronic switching or control logic, thereby improving reliability while keeping the control mechanism relatively simple.
Data Source
AI summary
A rotary hammer operable in a first mode in which only a hammering operation to reciprocate a tool bit along a drive axis is performed and a second mode in which the tool bit is rotationally driven about the drive axis. The rotary hammer includes a motor, a controller to control operation of the motor, a trigger moveable between an off position and an on position, a mode selection dial operable to select the first or second mode, a lock mechanism moveable between a first position and a second position, a linkage moveable between a third position and a fourth position, and a switch in communication with the controller. The switch communicates with the controller to operate the motor at full power or communicates with the controller to operate the motor at a variable speed based on the position of the trigger between the on position and the off position.