Shear Wrench Layout With Bolt Tip Ejection for Lower Fatigue
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Solution Overview
Problem
Shear wrench tools cause user fatigue due to the need to counteract the moment of force from the motor and transmission weight, and existing designs complicate the removal of the sheared bolt tip.
Innovation Solution
A shear wrench tool with an electric motor, planetary gear transmission, and an ejection mechanism, where the motor, transmission, and output section are coaxial, and a handle is positioned to balance moments of force, and an ejection mechanism using impact parts and a spring to dislodge the sheared bolt tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a handle is provided at the rear of the tool to counter the moment of force, then the tool can be operated, but user fatigue increases due to the counter moment required at the wrist
Solution Approach 1:
The handle is positioned asymmetrically at the front of the tool rather than at the rear, changing the location of the counterbalancing force application point. This asymmetric placement allows the counter moment to be applied at the front output section instead of requiring wrist effort at the rear, thereby maintaining tool operability while eliminating user fatigue.
2Productivity
If the sheared tip remains in the tool after cutting, then the cutting function is complete, but manual removal is required before tightening another bolt reducing productivity
Solution Approach 1:
The ejection mechanism automatically removes the sheared tip from the second output sleeve without requiring manual intervention. The system uses the rotational motion already present during or after the cutting operation to drive the ejection mechanism, which propels the sheared tip out of the tool, allowing continuous operation and eliminating the need for manual removal steps.
3Device complexity
If a coaxial arrangement of motor, transmission and output sleeves is used, then the tool structure is simplified, but the ejection mechanism must be integrated into this compact space
Solution Approach 1:
The ejection mechanism is nested within the existing coaxial structure of the motor, transmission, and output sleeves. The first impact part is positioned inside the second output sleeve, and the biasing means are contained within the same axial space, allowing the ejection mechanism to be integrated into the compact coaxial arrangement without increasing overall structural complexity.
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
Reduces user fatigue by balancing moments of force and efficiently ejects the sheared bolt tip, allowing for continuous operation without manual intervention.
Implementation Method 1
biasing means for urging the first active surface into engagement with the second active surface... the biasing means subsequently urges the first impact part back into engagement with the second impact part for generating an impulse
Implementation Method 2
interaction between the first and second active surfaces causes the first impact part to disengage from the second impact part... for generating an impulse which is transferred via the second impact part to a sheared bolt tip
Data Source
AI summary
A shear wrench tool including an electric motor, an output section having first and second output sleeves and a transmission for transferring torque from the motor to the output section wherein in use the output sleeves are caused to be rotated in opposite directions relative to each another, the first output sleeve configured for mating with a nut and the second output sleeve configured for mating with a tip of a bolt to be sheared; the shear wrench tool further comprising an ejection mechanism having a first impact part which is both rotationally and axially movable and which has a first active surface, a second impact part which is rotationally restricted but axially movable and which has a second active surface, the ejection mechanism also having biasing means for urging the first active surface into engagement with the second active surface.