Luggage Compartment Hinge With Ratchet-Set Torsion Spring Damping
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Solution Overview
Problem
Existing hinges for luggage compartments in vehicles and aircraft face challenges in optimizing handling and safety, particularly in ensuring controlled opening and closing mechanisms that meet safety requirements under varying loads and flight conditions.
Innovation Solution
A hinge design featuring a torsion spring twisted in the opening direction, a damping element, and an adjustment mechanism with a ratchet wheel and pawl system, allowing for secure locking without axial preload, and a stop element to prevent over-tensioning, ensuring uniform opening speed and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a torsion spring is used to assist the opening movement, then the opening force is improved, but the risk of uncontrolled opening and over-tensioning increases
Solution Approach 1:
The ratchet wheel and pawl mechanism is configured to prevent over-tensioning of the torsion spring before it can cause damage. The pawl engages with the ratchet teeth to block further rotation when the spring reaches its maximum pre-tension, thereby preventing harmful over-tensioning while maintaining the assisted opening force.
Solution Approach 2:
The torsion spring is twisted in the opening direction (opposite to conventional closing-direction twisting), which changes the stress distribution and allows for controlled pre-tension adjustment. This parameter change enables the spring to provide opening assistance while working within safe stress limits defined by the stop element.
2Speed
If the torsion spring is pre-tensioned to assist opening, then the opening speed is improved, but the risk of damage from over-tensioning increases
Solution Approach 1:
The stop element (comprising stop disc, stop pin, and limiter) is pre-configured to engage before the torsion spring can be over-tensioned. This preliminary action prevents excessive pre-tensioning that would damage the spring, while still allowing sufficient pre-tension to achieve uniform and relatively high opening speed.
Solution Approach 2:
The ratchet wheel and pawl mechanism provides mechanical feedback that prevents further tightening once the maximum safe pre-tension is reached. The pawl engages with the ratchet teeth to provide audible and tactile feedback, indicating that the spring has reached its maximum pre-tension limit, thereby preventing over-tensioning that would reduce spring durability.
3Reliability
If a damping element is added to control opening movement, then the control reliability is improved, but the device complexity increases
Solution Approach 1:
The damping element is integrated into the existing hinge structure by utilizing the bearing bushings and axle tube as mounting points. The damping element connects between the axle tube and the bearing bushing, merging the damping function with the existing rotational support structure, thereby controlling opening movement without significantly increasing overall device complexity.
4Manufacturing precision
If the torsion spring is twisted in the opening direction, then the pre-tension control is improved, but the manufacturing complexity increases
Solution Approach 1:
The adjusting element with the detent mechanism allows dynamic adjustment of the torsion spring pre-tension after assembly. The pawl and ratchet wheel enable incremental adjustment of the spring tension by rotating the adjusting element, which changes the effective length and pre-tension of the spring. This dynamic adjustment capability compensates for the increased manufacturing complexity by allowing precise pre-tension control in the field.
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 hinge provides secure, controlled opening and closing of luggage compartments, accommodating varying loads and preventing damage from over-tensioning, while ensuring uniform opening speed and enhanced safety.
Implementation Method 1
A torsion spring is located inside the axle tube, attached to the axle tube at its first end and connected at its second end to an adjusting element for the spring's preload.
Implementation Method 2
The hinge has a damping element for its pivoting movement, which is arranged in a rotationally secure manner in the first bearing bushing of the second hinge leaf and is connected to the axle tube on the other hand.
Data Source
Figure 1
Figure 2~3
AI summary
A hinge for luggage compartments comprises two hinge leaves, the first of which has one bearing bushing and the second of which has two. The bearing bushing of the first hinge leaf is rotatably mounted between the bearing bushings of the second hinge leaf about a common hinge axis. A torsion spring is located in an axle tube, which is rotationally fixed to the bearing bushing of the first hinge leaf and rotatably mounted in the bearing bushings of the second hinge leaf. The torsion spring is attached at its first end to the axle tube and connected at its second end to an adjustment element for the spring's preload. A damping element for the hinge's pivoting movement is arranged in a rotationally fixed manner in the first bearing bushing of the second hinge leaf and is also connected to the axle tube.The adjusting element is used for preloading the torsion spring and essentially comprises three elements: A) a detent element with a ratchet wheel featuring an outer gear ring, arranged in the second bearing bushing of the second hinge leaf; B) a pawl mounted on the second bearing bushing for engaging the outer gear ring of the ratchet wheel; and C) a stop element that limits the rotation angle α of the adjusting element. The arrangement of the torsion spring, pawl, and ratchet wheel ensures the locking action of the pawl even without axial preload on the torsion spring. In particular, with this hinge, it is not necessary to anchor the torsion spring in the axle tube or on the adjusting element with axial tensile strength. Two hinges per luggage compartment door are typically used in luggage compartments for cars and aircraft.