Fold-out Ramp Counterbalance Mechanism for Torque Reduction
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Solution Overview
Problem
Fold-out ramps for vehicles face challenges with torque requirements due to their length, making them heavy and difficult to manually operate, especially when power sources fail, and often require obtrusive hydraulic or pneumatic devices that complicate access and lack energy storage for motor preservation.
Innovation Solution
A ramp assembly with a counterbalance mechanism using a lug, flexible line, and spring system that allows for reciprocating motion between stowed, deployed, and neutral positions, reducing torque requirements and enabling manual operation by compressing springs to counteract the ramp's weight, thus minimizing the need for large power sources and obtrusive actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the ramp length is increased to provide a more gradual slope for accessibility, then the ramp becomes heavier and requires more torque for reciprocation, but accessibility is improved
Solution Approach 1:
The patent employs a spring-based counterbalance mechanism that provides an upward force to offset the ramp's weight during reciprocation. The spring is anchored to the vehicle structure and connected to the ramp via a linkage system, creating a counterbalancing effect that reduces the net force required to move the ramp between stowed and deployed positions.
Solution Approach 2:
The spring mechanism is pre-loaded to store potential energy that is released during ramp reciprocation. By positioning the spring in a pre-compressed or pre-stretched state, the system prepares the counterbalancing force in advance, reducing the peak torque requirement during actual ramp movement.
2Reliability
If larger electric motors or hydraulic actuators are used to overcome the torque requirement, then the ramp can be deployed reliably, but the devices become obtrusive and complicate access when the ramp is stowed
Solution Approach 1:
The spring counterbalance mechanism replaces the need for large motors or hydraulic actuators by providing mechanical counterbalancing. This eliminates complex power transmission systems and reduces the ramp assembly to a simple hinge and spring arrangement, significantly reducing device complexity while maintaining reliable operation.
Solution Approach 2:
The spring mechanism is self-actuating and requires no external power source. The ramp's own weight, when combined with the spring's counterbalancing force, creates a self-regulating system that automatically reciprocates the ramp without requiring motors, actuators, or control systems.
3Force
If hydraulic or pneumatic actuating devices are used to deploy the ramp, then the torque requirement is met, but the devices are obtrusive and make access to and from the vehicle difficult when the ramp is stowed
Solution Approach 1:
The spring-based counterbalance provides the necessary force to overcome the ramp's weight and moment arm, eliminating the need for hydraulic or pneumatic actuators. This results in a compact, streamlined ramp assembly that does not protrude into the vehicle interior when stowed, thereby improving access ease.
4Duration of action of stationary object
If no energy storage capabilities are provided, then the drive motor must work harder and its life is reduced, but adding energy storage would increase device complexity
Solution Approach 1:
The spring serves as a passive energy storage device that absorbs and releases energy during ramp reciprocation. By pre-loading the spring, energy is stored in advance and released to assist motor operation, reducing the motor's workload and extending its life without requiring complex active energy storage systems.
Solution Approach 2:
The spring mechanism automatically stores and releases energy based on the ramp's position, providing energy management without requiring control systems, sensors, or complex mechanisms. The system self-regulates energy transfer between the spring and ramp, extending motor life through passive energy recovery.
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 counterbalance mechanism reduces the torque needed to deploy and stow the ramp, allowing for manual operation and reducing the size and complexity of power sources, enhancing accessibility and extending the life of the drive motor.
Implementation Method 1
A spring is disposed between the restraint and the biasing element, wherein (1) movement of the ramp portion from the neutral position toward the stowed position compresses the spring, and (2) movement of the ramp portion from the neutral position toward the deployed position compresses the spring
Data Source
AI summary
A ramp assembly includes a ramp portion configured for reciprocating motion between a stowed position, a deployed position, and a neutral position. The ramp assembly includes a counterbalance comprising a lug associated with the ramp portion so that movement of the ramp portion toward the deployed position moves the lug along an arcuate path in a first direction, and movement of the ramp portion toward the stowed position moves the lug along the arcuate path in a second direction. A flexible line is coupled to the lug, and a restraint is fixedly located relative to the stowed position of the ramp portion. A biasing element is associated with the flexible line such that movement of the ramp portion away from the neutral position moves the biasing element compresses a spring disposed between the restraint and the biasing element.