Shear Wrench Ejector Sleeve for Compact Sheared Tip Removal

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Solution Overview

Problem

Existing shear wrench tools face challenges in compactly integrating an ejection mechanism while ensuring effective removal of sheared tips, which complicates subsequent fastening operations.

Innovation Solution

A shear wrench tool with a compact ejector mechanism using a spline-fit arrangement and a rotatable release sleeve, actuated by reversing the motor direction, allows for efficient ejection of sheared tips without interfering with the fastening process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an ejection mechanism is included in the shear wrench tool, then sheared tips can be automatically removed, but the tool occupies more space and becomes more complex

Engineering Contradiction:
Improveease of tip removalVSAvoidcomplexity of ejection mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The ejector pin is nested within the first output sleeve, with the pin fitting into a cylindrical bore of the sleeve. The spring is housed within a cavity in the first output sleeve. This nesting arrangement allows the ejection mechanism to be compact and integrated within the existing tool structure without adding significant external dimensions or complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The ejection mechanism is designed to be automatically actuated by the motor's reverse rotation. When the motor reverses direction after fastening, the rotation automatically drives the ejector pin outward through the first output sleeve, ejecting the sheared tip without requiring manual intervention or additional control mechanisms. The spring automatically resets the pin for the next operation.

Inventive Principle:
Principle #25Self-service

2Volume of moving object

If the ejection mechanism is made compact, then space is saved, but the ejection effectiveness may be compromised

Engineering Contradiction:
Improvevolume of ejection mechanismVSAvoidreliability of tip ejection
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The ejector pin is nested within the first output sleeve, with the pin fitting into a cylindrical bore of the sleeve. The spring is housed within a cavity in the first output sleeve. This nesting arrangement allows the ejection mechanism to be compact and integrated within the existing tool structure without adding significant external dimensions or complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The ejector pin has a rounded tip that contacts the sheared tip for ejection. The rounded contact surface ensures reliable engagement and effective ejection of the tip from the first output sleeve, maintaining ejection reliability despite the compact size of the mechanism.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Extent of automation

If the motor direction is reversed for ejection, then the ejection process is automated, but the fastening operation may be interrupted

Engineering Contradiction:
Improveautomation of ejection processVSAvoidfastening operation continuity
Core Design Contradiction:
Extent of automationVSProductivity

Solution Approach 1:

The motor operates in periodic cycles: forward rotation for fastening, then brief reverse rotation for ejection, then forward rotation again for the next fastening operation. This periodic action pattern automates the ejection process while minimizing interruption to the overall productivity, as the reverse rotation occurs only briefly between fastening cycles.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The ejection function is extracted as a separate, distinct phase from the fastening operation. The motor reverses only for the specific purpose of ejecting the tip, then returns to forward rotation for fastening. This separation allows automation of ejection without permanently interrupting the fastening workflow.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4338887B1Shear wrench tool
Publication Date: 2026.03.04 BLACK & DECKER CORP
  • EP4338887B1 patent drawingFigure 1
  • EP4338887B1 patent drawingFigure 2
  • EP4338887B1 patent drawingFigure 3

AI summary

A shear wrench tool comprising: a motor; a transmission operatively connected to the motor; a first socket arranged to engage a tip of a bolt to be sheared; a second socket arranged to engage a nut threaded on the bolt; wherein the first socket and second sockets are operatively connected to the transmission and rotate in opposite directions relative to each other when the motor provides torque to the transmission in use; an ejector mechanism comprising an ejector pin coaxial with the first and second sockets and moveable between a retracted position for enabling the tip of a bolt to be sheared to be received in the first socket and an extended position for urging a sheared tip from within in the first socket, the ejector pin being biased towards the extended position; wherein the tool is configured such that in use when the motor rotates in a first direction the first and second sockets tighten the bolt and nut without actuating the ejector mechanism whereby the ejector pin is blocked from moving to the extended position and when the motor rotates in a second direction the ejector mechanism is actuated whereby the ejector pin moves to the extended position for removing a sheared tip of the bolt from the first socket.