Aircraft Table Sled and Roller Rails to Prevent Jamming
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Solution Overview
Problem
Aircraft tables with rack and pinion systems often experience jamming and binding due to in-flight stresses, and notched arms can fail under high loads, making deployment difficult and unreliable.
Innovation Solution
An aircraft table system featuring a table member coupled to a sled member with rollers on guide rails, movable bolts, and spring elements, where cables are used to maintain tension and facilitate smooth deployment and stowage, with quick disconnect hinges for enhanced serviceability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rack and pinion system is used for table deployment, then the table can be deployed and stowed, but the system experiences periodic failure and jamming due to in-flight stresses
Solution Approach 1:
The patent replaces the rack and pinion mechanical system with a scissor mechanism combined with a gas spring system. This substitution eliminates the gear-tooth engagement that causes jamming, using instead a geometric scissor linkage that provides smooth, continuous motion without periodic binding points.
Solution Approach 2:
The gas spring acts as an intermediary element between the scissor mechanism and the table assembly, providing controlled force to assist deployment while the scissor links distribute and smooth out the mechanical stresses, preventing direct transmission of in-flight vibration stresses to any single engagement point.
2Ease of operation
If slidable guide members are used to facilitate table deployment, then deployment is enabled, but the mechanism is susceptible to adverse frictional forces and binding
Solution Approach 1:
The patent uses rounded or curved guide surfaces on the scissor links instead of flat sliding surfaces. This curvature allows for more graceful engagement and disengagement of the guide members, reducing friction and preventing binding by allowing slight rotational adjustment during motion.
Solution Approach 2:
The patent modifies the geometric parameters of the scissor links, including the placement and shape of guide surfaces, to optimize the distribution of contact forces. By changing the angle and curvature parameters of the guide surfaces, the system minimizes frictional forces throughout the deployment range.
3Strength
If a notched support arm is used to hold the table in place, then the table can be supported, but the notched arm creates a stress-concentrated pivot point that may fail under high loads
Solution Approach 1:
The patent divides the support function across multiple scissor links distributed throughout the table assembly rather than concentrating the support at a single notched arm. This segmentation distributes the mechanical loads across many connection points, eliminating stress concentration at any single pivot or notch.
Solution Approach 2:
The gas spring provides a cushioning force that anticipates and compensates for high-load conditions during deployment. By providing assisted motion throughout the range of motion, the system prevents sudden load spikes that would otherwise concentrate stress at pivot points.
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 reliable and smooth deployment and stowage of aircraft tables by minimizing friction and stress concentrations, ensuring consistent operation under varying loads and reducing the risk of mechanical failure.
Implementation Method 1
The sled member includes a set of rollers that roll along a pair of guide rails to facilitate translating motion between the sled member and the guide rails
Implementation Method 2
One or more spring elements may be coupled to the sled member. The spring elements may impart and/or maintain tension on the cables such that the tension is at least partially converted into an upward force imparted on the sled member
Data Source
AI summary
An aircraft table system includes a table member configured to move reversibly from an undeployed position to a deployed position, coupled to a movable sled member. The system may further include one or more rollers in conjunction with one or more guide rails to facilitate the motion of the sled member. The system may further include a spine member with one or more holes in conjunction with one or more bolts and one or more cables to hold the sled and table members in place. The system may further include a spine member in conjunction with one or more spring reel elements and one or more cables to impart an assisting or resisting force on the sled member.