Power Tool Clutch Assembly to Stop Fastener Return Rotation
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Solution Overview
Problem
Existing power tools, such as electric wrenches, require manual swinging of the grip during the return stroke to prevent the fastener from rotating, which is inefficient and can lead to unintended loosening.
Innovation Solution
A power tool design incorporating a clutch assembly with a first and second shaft locking assembly that allows the output shaft to rotate independently of the transmission shaft during the return stroke, using mechanisms like shaft locking rings and reversing wheels to control torque direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the power tool uses a motor to tighten or loosen the fastener, then the power tool can automatically drive the fastener, but during the return stroke the electric wrench drives the fastener to rotate which causes unintended loosening or tightening
Solution Approach 1:
The clutch assembly dynamically changes the engagement state between the transmission shaft and output shaft based on rotation direction. During forward stroke, the clutch engages to transmit torque; during return stroke, the clutch disengages to prevent torque transmission, allowing the transmission shaft to rotate independently while the output shaft remains stationary.
Solution Approach 2:
The clutch assembly segments the power transmission path into two independent rotational paths: one for the transmission shaft and another for the output shaft. This segmentation allows the transmission shaft to rotate during return stroke without driving the output shaft and fastener, solving the unintended rotation problem.
2Reliability
If the user swings the grip manually during return stroke to prevent fastener rotation, then the fastener does not rotate unintentionally, but the operation becomes inefficient and requires additional manual effort
Solution Approach 1:
The clutch assembly automatically detects the rotation direction and adjusts the engagement state without user intervention. The friction members and elastic elements self-regulate the clutch engagement based on the applied torque direction, eliminating the need for manual grip swinging while maintaining fastener rotation control.
3Reliability
If the clutch assembly includes friction members and elastic elements for automatic engagement, then the fastener rotation is controlled automatically, but the device complexity increases
Solution Approach 1:
The elastic elements act as intermediaries between the friction members and the shafts, providing automatic engagement and disengagement based on torque direction. The elastic elements store and release energy to maintain continuous contact between friction members and shafts, enabling automatic clutch operation without complex control mechanisms.
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
Prevents the fastener from rotating during the return stroke, enhancing efficiency and ensuring the fastener remains tightened or loosened as intended without manual swinging.
Implementation Method 1
the friction member prevents the first shaft locking ring from driving the reversing wheel to rotate, and the reversing wheel remains stationary to prevent the transmission shaft from rotating
Data Source
Figure 1
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Figure 4
AI summary
Provided is a power tool. The power tool includes a housing formed with or connected to a grip for holding; a motor including a drive shaft rotating about a first axis; a clutch assembly driven by the drive shaft; and a transmission assembly connecting the motor to the clutch assembly. The clutch assembly includes a first shaft locking assembly, a second shaft locking assembly, a transmission shaft, and an output shaft, the output shaft includes a first output shaft, the first shaft locking assembly is sleeved on the transmission shaft and the first output shaft, and the second shaft locking assembly connects the transmission assembly to the first shaft locking assembly. When the drive shaft remains stationary and the first output shaft rotates along a first direction, the first shaft locking assembly prevents the transmission shaft from rotating, and the transmission shaft remains stationary. When the drive shaft remains stationary and the first output shaft rotates along a second direction, the first shaft locking assembly drives the transmission shaft to rotate along the second direction, and the second shaft locking assembly prevents the transmission shaft and the first output shaft from rotating. The preceding technical solutions are adopted, thereby providing a power tool so that a fastener does not rotate along with the power tool during the return stroke.