Handheld Power Tool Ring Gear Slip Clutch for Overload Protection
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Solution Overview
Problem
Handheld power tools can experience locked operating conditions where the gear and/or tool holder are damaged due to the drive motor continuing to rotate, leading to potential damage from excessive torque.
Innovation Solution
Incorporation of a slip clutch mechanism with a fixed ring gear having a breakaway torque less than or equal to the maximum torque, arranged between the fixed ring gear and transmission components to prevent gear locking and protect the tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive motor continues to rotate during locked operating conditions, then the drive motor maintains its rotational function, but the gear and/or tool holder are damaged due to excessive torque
Solution Approach 1:
The fixed ring gear acts as an intermediary slip clutch mechanism between the drive motor and the gear transmission. When excessive torque is detected (when breakaway torque is reached), the fixed ring gear slips relative to the transmission housing, allowing the drive motor to continue rotating while preventing the excessive torque from being transmitted to the gear and tool holder, thus protecting them from damage.
2Reliability
If a fixed ring gear with breakaway torque is implemented to prevent gear locking, then gear damage is prevented, but the device complexity increases due to the slip clutch mechanism
Solution Approach 1:
The slip clutch function is merged with the fixed ring gear component itself. The fixed ring gear is designed to have a breakaway torque characteristic and is arranged between the transmission housing and the gear, combining the structural element (ring gear) with the protective function (slip clutch) into a single integrated component, thereby reducing overall device complexity.
3Ease of operation
If the fixed ring gear is arranged to have breakaway torque less than or equal to maximum torque, then the tool operates safely under normal conditions, but the fixed ring gear may move during operation affecting precision
Solution Approach 1:
The fixed ring gear is designed with dynamic characteristics, allowing it to be fixed during normal operation (when torque is below breakaway torque) and to slip or move when excessive torque is detected (when torque reaches breakaway torque). This dynamic behavior enables the system to maintain precision during normal operation while automatically protecting itself under overload conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The slip clutch effectively prevents gear locking and associated damage by allowing the fixed ring gear to move when the breakaway torque is reached, ensuring the tool operates safely and efficiently.
Implementation Method 1
the fixed ring gear has the breakaway torque which is less than or equal to the maximum torque
Data Source
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AI summary
A handheld power tool (100) is disclosed, comprising a housing (110), a drive motor (114) having a drive shaft (116), a gear mechanism (118) drivable by means of the drive shaft (116), the gear mechanism (118) comprising a gear housing (119), a gear cover (136), and a fixed ring gear (129), the gear cover (136) closing the gear housing (119) at least in sections, and a tool holder (150) for receiving an insert tool (140), the tool holder (150) being drivable by means of the gear mechanism (118). It is proposed that the fixed ring gear (129) be arranged such that the fixed ring gear (129) has a breakaway torque.