Spring-Assisted Aircraft Seat Actuation for Lie-Flat Return
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Solution Overview
Problem
Aircraft seats configured to actuate between upright and lie-flat positions often fail to return to the upright position when power is cut or excessive loads are applied, leading to safety issues and inefficient use of space due to the size and number of actuators required.
Innovation Solution
Incorporating a spring-assisted actuation system that uses springs and spring hooks to counterbalance loads and assist the actuator motor, allowing for controlled movement between positions and reducing the need for multiple actuators, thereby minimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an actuator motor is used to actuate the aircraft seat between upright and bed positions, then the seat can transition between positions, but the actuator motor requires valuable living space within the passenger compartment
Solution Approach 1:
The patent applies the counterweight principle by using springs to counterbalance the weight of the upper aircraft seat assembly. The springs are configured to compress during actuation and provide a return force that assists the actuator motor, effectively reducing the force requirement and allowing for a more compact actuator design that occupies less space in the passenger compartment.
2Reliability
If the actuator motor is sized to handle excessive loads such as passenger weight, then the seat can return to upright position under load, but the actuator motor size increases and consumes more space
Solution Approach 1:
The springs are configured to compress when the seat is in the bed position and extended when in the upright position, providing a mechanical counterbalance to the seat assembly weight. This reduces the load on the actuator motor by approximately half, allowing the motor to be sized for normal operation rather than maximum load conditions, thereby reducing its size and space requirements.
Solution Approach 2:
The springs perform preliminary work by storing mechanical energy during the actuation process. As the actuator motor moves the seat from upright to bed position, the springs compress and store energy. This stored energy is then released to assist the motor in returning the seat to the upright position, effectively performing part of the work before the motor needs to act again.
3Use of energy by moving object
If power is cut to the actuator motor, then energy consumption is reduced, but the seat cannot return from bed position to upright position
Solution Approach 1:
The spring-assisted system provides self-service capability for seat return. When power is cut to the actuator motor, the compressed springs automatically generate a return force that propels the upper seat assembly back to the upright position without requiring additional energy input or motor operation. The system uses the mechanical energy stored in the springs to service itself.
4Reliability
If multiple actuators are used to ensure reliable seat actuation, then the seat can handle various load conditions, but the device complexity and space requirements increase
Solution Approach 1:
The patent merges the function of multiple actuators into a single actuator motor by combining mechanical advantage through the spring-assisted system. The springs provide mechanical assistance that multiplies the effective force of the single motor, allowing one actuator to perform the work that would otherwise require multiple actuators, thereby reducing system complexity.
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 spring-assisted system enables the aircraft seat to efficiently transition between positions, ensuring safety and optimizing space utilization by reducing the weight, cost, and complexity of the seat, while allowing for a lower bed height and more ergonomic compartment layout.
Implementation Method 1
The at least one spring is compressed by the at least one spring hook when the upper aircraft seat assembly is in the bed position. The compressing of the at least one spring is configured to generate a return force within the at least one spring.
Implementation Method 2
The compressing of the at least one spring is configured to generate a return force within the at least one spring. The at least one spring is configured to provide the return force against the at least one spring hook and assist the frame actuation assembly during actuation
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An aircraft seat may include an upper aircraft seat assembly (126), a lower aircraft seat assembly (128), and a frame actuation assembly (110) configured to actuate the upper aircraft seat assembly (126) relative to the lower aircraft seat assembly (128). The lower aircraft seat assembly (128) may include at least one spring (202) coupled to a foundation (108) with a sloped actuation surface configured to cause the upper aircraft seat assembly (126) to be at a decreased height when in a bed position. The compressing of the at least one spring (202) may be configured to counterbalance a load within the aircraft seat and generate a controlled actuation of the upper aircraft seat assembly (126) from an upright position to the bed position. A return force provided by the at least one spring (202) may assist the frame actuation assembly (110) during actuation of the upper aircraft seat assembly (126) from the decreased height of the bed position to the upright position.