Ratchet Fitting Structure for Precise Chromatograph Torque Limiting
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Solution Overview
Problem
The existing torque limiting connectors for chromatographs suffer from inaccuracies in torque transmission due to non-uniform deformation of components when a torque greater than the prescribed value is applied, leading to variations in the torque prescribed value.
Innovation Solution
A ratchet fitting design featuring a screw portion and an operating portion with an engaging member and an elastic member, where the elastic member's deformation allows for torque limitation by releasing engagement between the projection and protrusion, ensuring uniform deformation and accurate torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the upper portion and lower portion of the main body are integrated via a connecting portion, then the structure is simplified and manufacturing is easier, but the deformation of the abutment becomes non-uniform in the axial direction when torque is applied, leading to variation in torque prescribed value
Solution Approach 1:
The main body is divided into an upper portion and a lower portion that are separable, with the upper portion having a through-hole allowing the elastic member to pass through. This segmentation enables the elastic member to deform uniformly in the axial direction when torque is applied, ensuring consistent torque limitation performance without compromising manufacturing ease.
2Power
If the elastic member and engaging member are fitted tightly to transmit rotational force, then torque transmission efficiency is improved, but the engagement becomes too strong to release when excessive torque is applied, preventing torque limitation
Solution Approach 1:
The elastic member is designed with elastic properties that allow its engagement state to dynamically change based on applied torque. When normal torque is applied, the engagement is strong for efficient power transmission. When excessive torque is applied, the elastic member deforms and the engagement automatically releases, providing reliable torque limitation.
Solution Approach 2:
The engagement force between the elastic member and engaging member is made variable through the elastic properties of the material. The engagement strength changes based on the deformation state of the elastic member, which is controlled by the magnitude of applied torque, enabling both efficient power transmission and reliable torque limitation.
3Reliability
If the abutment is designed to deform inwardly to release engagement, then torque limitation function is achieved, but the deformation may not be uniform when the structure is integrated, causing variation in torque prescribed value
Solution Approach 1:
The main body is segmented into upper and lower portions with a through-hole configuration that allows the elastic member to deform uniformly along its entire length in the axial direction. This uniform deformation ensures that the abutment deforms consistently inwardly, releasing engagement at a predictable and consistent torque value.
Solution Approach 2:
The elastic member's deformation characteristics are optimized to ensure uniform dimensional changes in the axial direction when torque is applied. This controlled parameter change ensures consistent abutment deformation and reliable torque limitation at a precise prescribed value.
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 ratchet fitting achieves improved accuracy in torque transmission by allowing the elastic member to deform uniformly, preventing excessive torque from being applied to the screw portion, thus stabilizing the sealing force and reducing variations in the torque prescribed value.
Implementation Method 1
the elastic member has an outer peripheral surface and a holding member formed separately from the elastic member, a projection projecting inwardly is provided on the inner peripheral surface of the engaging member, a protrusion protruding outwardly is provided on the outer peripheral surface of the elastic member, the elastic member and the engaging member are fitted such that a rotational force is transmittable to each other due to engagement of the projection and the protrusion and engagement between the projection and the protrusion is releasable due to deformation of the elastic member
Data Source
AI summary
A ratchet fitting includes a screw portion and an operating portion. One of the screw portion and the operating portion has an engaging member, and the other one of the screw portion and the operating portion has an elastic member and a holding member formed separately from the elastic member. The elastic member and the engaging member are fitted such that a rotational force is transmittable to each other due to engagement of the projection and the protrusion and engagement between the projection and the protrusion is releasable due to deformation of the elastic member. The elastic member has a first fitting portion, the holding member has a second fitting portion, and the holding member and the elastic member are fitted such that the first fitting portion and the second fitting portion are fitted to each other in a rotation direction.