Quick Coupler Bearing Surface Geometry for Wear Reduction
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Solution Overview
Problem
Existing quick couplers for construction machines, such as excavators and loaders, experience premature wear and dimensional loss due to high pressure on bearing surfaces, leading to costly maintenance and downtime for re-machining.
Innovation Solution
A connection device with a cradle having concave cylindrical sectors and planar tangent surfaces, and a quick hitch coupler with conjugate bearing means, including convex cylindrical sectors and tangent planar surfaces, which distribute contact pressure linearly and reduce bending forces, enhancing compatibility with existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pin with circular arc bearing surfaces is used in conventional quick couplers, then the connection structure is simple, but the bearing surfaces experience high pressure causing rapid metal creep and dimensional loss
Solution Approach 1:
The invention changes the geometric parameters of the bearing surfaces from circular arc profiles to a combination of concave cylindrical sector and planar tangent surface. This parameter change redistributes the contact pressure from concentrated high-pressure zones to a more uniform linear distribution, reducing metal creep and extending service life while maintaining structural simplicity
Solution Approach 2:
The invention uses a concave cylindrical sector with a planar tangent surface instead of a purely circular arc profile. The cylindrical curvature provides smooth contact during rotation, while the planar tangent surface distributes the load more evenly at the end of rotation, reducing bending forces and preventing rapid wear
2Manufacturing precision
If bearing surfaces are re-machined to restore dimensions, then operational correctness is restored, but costly repairs and tool immobilization occur
Solution Approach 1:
The invention incorporates wear compensation features in the form of adjustable support means and replaceable inserts that can be pre-positioned to maintain correct bearing surface dimensions throughout the service life, eliminating the need for periodic re-machining and reducing downtime
3Force
If high pressure is concentrated on bearing surfaces during quick coupler operation, then the connection force is effective, but metal creep and dimensional loss occur rapidly
Solution Approach 1:
The invention changes the contact surface geometry from curved to a combination of cylindrical and planar surfaces, which fundamentally alters the pressure distribution pattern. The new geometry maintains effective connection force while distributing pressure linearly across the bearing surfaces, preventing localized metal creep and preserving dimensional stability
Data Source
Figure 1~2
Figure 3~4
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AI summary
The device (1) has a cradle equipped with a holder. The holder has a concave cylindrical sector and a flat tangential surface parallel to a plane (P) passing through an axis of the cylindrical sector and by an axis of pins (3). The holder receives a support unit supporting a rapid attachment coupler (13) whose shape is matched to that of the holder, at the end of rotation of the coupler with respect to the axis of the pins. Independent claims are also included for the following: (1) a rapid attachment coupler positioned at an end of an arm of a public works vehicle (2) a public works bucket comprising a connection device.