Handheld Tool Gear Interlock for Safe Percussion Drilling
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Solution Overview
Problem
Existing hand tool devices lack a simple, reliable, and safe mechanism to prevent switching to percussion drilling mode when the first gear ratio is set, leading to potential operational hazards and inefficiencies in drilling and screwing modes.
Innovation Solution
A protective device integrated with the operating device prevents switching to percussion drilling mode when the first gear ratio is set, using a mechanical or electrical mechanism to ensure safe operation, and allows for adjustable torque limiting in screwing mode while disabling it in drilling mode for high torque applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the hand tool device allows switching between first gear ratio and percussion drilling mode, then the tool can perform both high-torque screwing operations and high-speed drilling operations, but the operator may accidentally select an incompatible mode combination leading to operational hazards
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the operating device with interlocking mechanisms that prevent the selection of incompatible mode combinations. The first operating element (gear ratio selector) and second operating element (mode selector) are designed with mechanical or electrical interlocks that detect when the first gear ratio is selected and automatically block the percussion drilling mode from being activated, thereby preventing hazardous operational states before they can occur.
2Force
If the operating device allows simultaneous selection of first gear ratio and percussion drilling mode, then the tool can theoretically provide high torque and impact force, but this creates a conflict in power transmission paths that can damage the planetary gear
Solution Approach 1:
The patent implements preliminary action by designing the operating device to pre-establish the correct operational state before power transmission begins. The interlocking mechanism ensures that when the first gear ratio is selected for high-torque operations, the percussion mechanism is automatically disengaged or blocked in advance, preventing any conflict in power transmission paths that could damage the planetary gear during actual operation.
3Reliability
If the hand tool device includes a protective device to prevent mode conflicts, then operational safety is improved, but the structure of the operating device becomes more complex
Solution Approach 1:
The patent applies merging by integrating the protective function directly into the existing operating device structure. The first and second operating elements are combined with interlocking mechanisms that use the same mechanical or electrical connection pathways already present in the tool. This integration allows the protective device to prevent mode conflicts without requiring entirely separate control systems or adding significant structural complexity beyond the modified operating elements.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The device (12a) has an operating device (32a) for setting two transmission ratios and a percussion drilling mode. A protective device (226a) prevents operation in one of the transmission ratios when the tool device is in the drilling mode. The protective device prevents switching over of the tool device into the drilling mode when the transmission ratio is set. The protective device prevents switching over into the transmission ratio when the drilling mode is set, where maximum tool torque is greater than 15 nanometer and lesser than 15 nanometer in the two transmission ratios, respectively.