Cam-Driven Key Retention System for Earth-Working Tools
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Solution Overview
Problem
Existing tool retention systems for earth-working machines, such as those described in U.S. Pat. No. 4,067,657, face issues with wear-induced loosening of joints, requiring frequent replacement and potential cocking of components, leading to premature failure and increased maintenance costs.
Innovation Solution
A cam-driven key retention system comprising a sleeve with radially oriented holes, a pin with cam lobes, and keys that extend radially outward upon pin rotation, ensuring secure engagement of ground engaging tools to work implements while preventing cocking and allowing for easy replacement of worn components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If set screws are repeatedly tensioned to re-tighten worn components, then joint engagement is temporarily restored, but the retaining means eventually requires replacement due to excessive wear
Solution Approach 1:
The keys are designed as replaceable components that can be easily replaced when worn, rather than replacing the entire retaining means assembly. This allows the main structural components (sleeve, pin) to be reused while only replacing the worn keys, significantly reducing replacement time and cost.
Solution Approach 2:
The retaining means is divided into separate replaceable keys and a reusable sleeve-pin assembly. This segmentation allows selective replacement of only the worn keys while retaining the serviceable components, addressing the time loss issue.
2Ease of operation
If keys are separately extended to contact the ripper tip, then engagement is achieved, but the cylindrical pin may become cocked within the bore leading to premature loosening or damage
Solution Approach 1:
The keys are integrated with the pin as a single unit, eliminating the risk of cocking by ensuring that the keys and pin move together as one assembly. This merging of components prevents misalignment and premature failure.
3Reliability
If the retaining means components wear over time, then joint loosening occurs, but complete replacement of the retaining means is required instead of individual components
Solution Approach 1:
The retaining means is segmented into replaceable keys and a reusable sleeve-pin assembly. This allows individual replacement of worn keys without replacing the entire assembly, improving ease of manufacture and maintenance.
Solution Approach 2:
Only the worn keys are discarded and replaced, while the sleeve and pin assembly are recovered and reused. This selective replacement approach reduces manufacturing costs and simplifies maintenance operations.
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 provides a reliable, low-maintenance connection that prolongs the life of earth-working machine components, reduces servicing time, and maintains operator confidence in tool durability by ensuring consistent engagement and easy key replacement.
Implementation Method 1
The pin may have a cam lobe located at an end adjacent the radially oriented hole of the sleeve and radially offset from a central axis. The key may be movable during rotation of the pin from a retracted position to an activated position at which the key extends radially beyond the outer surface of the sleeve.
Data Source
AI summary
A retention system is provided for use in connecting a replaceable tool to a work implement. The retention system may have a sleeve configured to be received within corresponding bores in the work implement and the replaceable tool. The sleeve may have a radially oriented hole passing through an outer surface thereof. The retention system may also have a pin disposed within the sleeve. The pin may have a cam lobe located at an end adjacent the radially oriented hole of the sleeve and radially offset from a central axis. The retention system may additionally have a key disposed within the radially oriented hole of the sleeve and configured to ride on the cam lobe. The key may be movable during rotation of the pin from a retracted position to an activated position at which the key extends beyond the outer surface of the sleeve.