Pivoting Thumb Stop System for Excavator Stick
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Solution Overview
Problem
Existing stop systems for excavating machines, which prevent the thumb from damaging the stick by using linkages or projections, often require complex linkages or large projections that can interfere with equipment operation and are difficult to adjust due to manufacturing tolerances and wear.
Innovation Solution
A stop system featuring a pivotable shoe with a fastener and an adjusting system using a slug with an eccentric hole and locking structure, allowing for adjustable placement of stop shoes to mitigate force concentration and prevent damage, while minimizing protrusions on the stick.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linkage is used as a stop system, then the thumb can be stopped against the stick, but the system requires complicated linkages to transmit large forces
Solution Approach 1:
The patent extracts the stop function from a complex linkage system and implements it through a simple protrusion on the stick that directly contacts the thumb. This eliminates the need for complicated links while maintaining the stopping function, directly resolving the contradiction between reliability and device complexity.
2Reliability
If projections are added to the stick for the stop system, then the thumb can be stopped, but large projections interfere with operation of the excavating equipment
Solution Approach 1:
The patent applies local quality by creating a small, localized protrusion at the specific contact point on the stick where the thumb stops, rather than adding large projections throughout the stick structure. This localized approach provides effective stopping while minimizing interference with overall equipment operation.
3Ease of manufacture
If the stop system is fixed during manufacturing, then installation is simple, but the stop system moves out of desired location due to manufacturing tolerances and wear
Solution Approach 1:
The patent implements dynamics by providing an adjustable stop system that can be repositioned after manufacturing. The adjustable protrusion or shoe can be moved to compensate for manufacturing tolerances and wear, maintaining reliable positioning while keeping the initial installation simple.
4Reliability
If the thumb contacts the stick with high force, then the thumb cylinder and related components are stressed, but reducing the stop force reduces the effectiveness of the stop system
Solution Approach 1:
The patent applies beforehand cushioning by designing the stop contact surface and protrusion geometry to distribute the stopping force over a larger area. This cushioning effect reduces peak contact forces on the thumb cylinder and related components while maintaining effective stopping capability.
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 system effectively reduces the risk of damage to the stick by evenly distributing forces and allowing for precise adjustment of stop shoes, enhancing operational reliability and ease of installation.
Implementation Method 1
a slug defining an eccentric hole
Implementation Method 2
a locking structure defined by an outer circumference of the slug, the locking structure dimensioned and configured to lock the slug in a rotational orientation
Data Source
AI summary
A stop system may include: a first member; a second member movable with respect to the first member, the first and second members being different parts of a common machine; a body including a boss defining a hole; a base plate at least one of: attached to and part of, the body on the side of the body opposite of the boss, the body and base plate forming a shoe; and a fastener extending through the hole in the boss thereby pivotally attaching the body to one of the first and second member. A method of providing a stop for stopping a thumb against a stick is also described.