Tray Arm Joint With Two-Tier Friction to Prevent Whipping
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Solution Overview
Problem
Existing tray arm assemblies in medical settings lack effective mechanisms to prevent excessive movement or damage from applied forces, either allowing unwanted movement or risking joint damage due to lack of locking mechanisms.
Innovation Solution
A tray arm assembly with a two-tier friction mechanism, comprising a joint body, a shaft, and a slip clutch assembly with first and second clutch plates, where the first friction mechanism prevents movement unless sufficient torque is applied, and the second friction mechanism prevents whipping by exerting drag torque, ensuring joints are not damaged by excessive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a locking mechanism is added to prevent tray movement, then stability is improved, but the joint may break if excessive force is applied
Solution Approach 1:
The patent converts the harmful effect of excessive force into a beneficial feature by designing a friction mechanism that allows controlled slippage. When excessive force is applied, the clutch plates slip relative to each other, dissipating the excess energy through friction rather than transmitting it to the joint structure, thereby protecting the joint from damage while maintaining stability under normal conditions
2Ease of operation
If no locking mechanism is provided, then ease of operation is improved, but the tray moves excessively in response to small forces
Solution Approach 1:
The patent changes the friction parameter dynamically through the spring mechanism. The spring applies a varying friction force that adapts to the operational state: under normal conditions, the friction is sufficient to prevent excessive movement, while when sufficient force is applied by the user, the friction threshold is overcome and the tray becomes freely adjustable, providing both stability and ease of operation
3Stability of the object's composition
If friction is increased to prevent movement, then stability is improved, but torque required to move the tray increases
Solution Approach 1:
The patent applies partial friction through the clutch plate design, where only a portion of the maximum friction force is needed to maintain stability during normal operation. The spring applies just enough friction to prevent unwanted movement, but not enough to prevent intentional adjustment when sufficient user force is applied. This partial action approach maintains stability while requiring reasonable torque for operation
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 two-tier friction mechanism allows controlled movement of the tray arm assembly while preventing damage from excessive torque, ensuring stability and ease of use by allowing movement only when sufficient force is applied, thus enhancing the durability and usability of the assembly.
Implementation Method 1
the force compresses the clutch stack causing a friction between the plurality of first clutch plates and the plurality of second clutch plates with respect to a rotation of the shaft relative to the joint body
Data Source
AI summary
Particular embodiments disclosed herein provide a joint of a tray arm assembly, comprising a joint body, a shaft configured to rotate relative to the joint body about a longitudinal axis of the shaft, and a slip clutch assembly, comprising a clutch stack, including a plurality of first clutch plates keyed to the shaft and a plurality of second clutch plates keyed to the joint body. The clutch stack further comprises a spring configured to selectively exert a force on the clutch stack, wherein the force compresses the clutch stack causing a friction between the plurality of first clutch plates and the plurality of second clutch plates with respect to a rotation of the shaft relative to the joint body.