Quick Coupler Wedge Locking for Pin Retention on Hydraulic Failure
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Solution Overview
Problem
Quick couplers for attachments on earth working machines fail to securely hold the attachment due to hydraulic failure, leading to the attachment either falling off or swinging down, posing safety risks.
Innovation Solution
A wedge locking element with a planar pin engagement surface and a clamp device that prevents the pin from applying a loading force on the wedge during failure, ensuring the pin remains engaged, even without additional hydraulic actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sloping wedge surface is used to retain the pin, then the wedge can be hydraulically operated to lock and unlock the pin, but hydraulic failure can cause the pin to drive the wedge backward to a release position
Solution Approach 1:
The patent applies preliminary anti-action by designing the wedge with a non-sloping engagement surface that proactively prevents the pin from driving the wedge backward. The engagement surface is oriented perpendicular to the pin axis, creating a mechanical stop that counteracts the harmful effect of hydraulic failure before it can cause pin release.
Solution Approach 2:
The patent changes the geometric parameter of the wedge engagement surface from sloping to non-sloping (perpendicular orientation). This parameter change fundamentally alters the mechanical interaction between the pin and wedge, transforming the wedge from a component that can be driven backward to one that maintains a fixed engagement position.
2Strength
If the pin engagement surface is sloping, then the wedge can engage the pin effectively, but the pin can apply loading to drive the wedge to a release position during failure
Solution Approach 1:
The engagement surface is designed with a non-sloping orientation that proactively prevents the pin from applying harmful loading to the wedge. The perpendicular orientation creates a mechanical stop that counteracts the harmful effect of pin-driven wedge movement before it can occur.
Solution Approach 2:
The patent changes the angular parameter of the engagement surface from sloping (acute angle) to non-sloping (perpendicular orientation). This parameter change eliminates the mechanical advantage that would otherwise allow the pin to drive the wedge backward under failure conditions.
3Reliability
If a safety locking device is added to retain the front pin, then the attachment cannot fall completely from the coupler, but the device complexity increases
Solution Approach 1:
The safety locking device is designed to be self-actuating through the failure of the hydraulic system. When hydraulic pressure is lost, the spring automatically drives the locking element into engagement with the pin, requiring no additional control systems or complex actuation mechanisms.
Solution Approach 2:
The spring acts as an intermediary element that translates the failure condition (loss of hydraulic pressure) into the desired safety action (engagement of locking element). This intermediary mechanism provides a simple, reliable solution without requiring complex sensing or control systems.
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 solution effectively reduces the risk of attachment detachment by maintaining the pin's engagement with the coupler, enhancing safety and reliability without additional hydraulic components.
Implementation Method 1
a sloping wedge surface, characterised in that projecting from the wedge surface is an engagement surface with which the attachment pin can engage but not apply any substantial loading to the wedge locking element
Implementation Method 2
the clamp device includes an arm mounted to be pivotable about a pivot axis, the arm incorporating a pin engagement portion distal from the pivot axis
Data Source
AI summary
A wedge locking element (10) for a locking device of a quick coupler A for coupling the pin P2 of an attachment to earth working machinery. The wedge locking element (10) has a sloping wedge surface (13). Projecting from the wedge surface (13) is an engagement surface (12) with which the attachment pin P2 can engage but not apply any substantial driving force to the wedge locking element (10) in the event of failure of a force maintaining the wedge locking element (10) in a position where the pin P2 is retained with the coupler A. The pin engagement surface (12) lies in a plane that is substantially in line with the direction in which the locking element (10) is, in use, moved by the driving force.