Push-Push Fuel Tank Lid Lock with Radial Cam
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Solution Overview
Problem
Existing 'push-push' locks for fuel tank lids in cars and motorcycles face issues of excessive dimensions due to the alignment of the heart-shaped cam with the roto-translating pin, leading to unbalanced force systems and increased friction, as well as difficult assembly and high force requirements for operation.
Innovation Solution
The heart-shaped cam is positioned in a detached parallel configuration with respect to the roto-translating pin, connected via a flexible rocker and semi-arch fork, allowing for balanced force transmission and reduced dimensions through a modified cam-tappet interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the heart-shaped cam is aligned with the roto-translating pin, then the mechanism can be compact in one direction, but the overall dimensions increase in the parallel direction and friction increases
Solution Approach 1:
The heart-shaped cam is repositioned from an axial alignment with the roto-translating pin to a radial position, utilizing the circular space around the pin's rotation path. This dimensional reconfiguration reduces the overall length of the mechanism while maintaining functional effectiveness.
Solution Approach 2:
A flexible connector is introduced as an intermediary element between the heart-shaped cam and the roto-translating pin. This flexible link transmits the cam's action to the pin while accommodating misalignment and reducing friction, enabling the cam to act effectively from its repositioned location.
2Device complexity
If the heart-shaped cam is positioned in alignment with the roto-translating pin, then the structure is simplified, but the force system becomes unbalanced and friction increases
Solution Approach 1:
The cam is moved from axial alignment to a radial position around the pin, changing the dimension of interaction. This repositioning creates a more balanced force distribution during the pin's rotational movement, reducing friction and energy loss.
Solution Approach 2:
The flexible connector serves as a mediator that transmits force from the cam to the pin while accommodating the angular displacement. This intermediary element smooths force transmission and reduces friction by allowing gradual engagement rather than direct rigid contact.
3Volume of moving object
If the heart-shaped cam is aligned with the roto-translating pin, then the mechanism is compact, but assembly becomes difficult
Solution Approach 1:
By positioning the cam radially around the pin rather than axially aligned, the components can be assembled independently and then connected via the flexible link. This separates the assembly steps, making the process easier while maintaining compact overall dimensions.
Solution Approach 2:
The flexible connector acts as an intermediary that simplifies assembly by allowing the cam and pin to be positioned independently. The flexible nature of the connector accommodates slight misalignments during assembly, making the manufacturing process more tolerant and easier to execute.
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
This configuration results in lower overall dimensions, reduced friction, and easier assembly, enabling efficient operation with balanced forces and lower force requirements for opening and closing the lid.
Implementation Method 1
The said roto-translating pin is inserted inside a housing and guiding chamber, in which it is free to slide axially and rotate, being constantly subject to the force of an ejection spring compressed during the closing of the lid.
Data Source
AI summary
The present invention relates to an opening and closing device of push-push type for lids, with particular reference to the lids of fuel tanks in cars and motorcycles, which uses a mechanism comprising a heart-shaped cam (6) and a roto-translating pin (3), in which the cam (6) is positioned in detached and parallel position with respect to the roto-translating pin (3) and in which the heart-shaped cam (6) and the pin (3) are connected by means of a rocker (8).