Self-tightening Elastic Line Ligator with Spring Mechanism
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Solution Overview
Problem
Current hemorrhoid ligation methods using aprons or elastic lines face issues such as limited inner diameter, elastic retraction force degradation, and complications like slippage and postoperative bleeding due to instability in ligation tension.
Innovation Solution
A self-tightening elastic line ligator with a double-layer elastic line structure and an automatic tensioning mechanism that uses a compression spring to rapidly reduce the loop size at the front end, ensuring a secure and consistent ligation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual tightening of elastic line loop is used, then the ligation can be performed, but the elastic line loop is easy to slip off the tissue and the tension is unstable
Solution Approach 1:
The device employs an automatic tensioning mechanism that self-adjusts the elastic line loop tension without requiring manual intervention. The spring-loaded ratchet system automatically maintains optimal tension on the elastic line, eliminating the need for manual tightening while preventing slippage and ensuring stable ligation.
Solution Approach 2:
The manual mechanical tightening process is replaced with an automated mechanical tensioning system. The device uses a spring mechanism combined with a ratchet and pawl system to automatically apply and maintain the necessary tension on the elastic line, substituting the manual operation with an automated mechanical solution.
2Ease of manufacture
If apron is used for ligation, then the ligation material is simple to use, but the inner diameter cannot be infinitely small and the elastic retraction force weakens over time
Solution Approach 1:
The invention changes the critical parameter of inner diameter from fixed (as in aprons) to variable and adjustable. The elastic line can be tensioned to achieve minimal or near-zero loop diameter, and the tension can be dynamically adjusted to maintain optimal elastic retraction force throughout the healing process, overcoming the limitations of fixed apron dimensions.
Solution Approach 2:
The static apron structure is replaced with a dynamic elastic line system that can adapt its tension over time. The automatic tensioning mechanism allows the ligation to maintain optimal force as the tissue heals and shrinks, providing dynamic adjustment rather than the fixed geometry of traditional aprons.
3Ease of operation
If elastic line loop is tightened manually, then the ligation can be applied, but it is difficult to control the tightening strength and the elastic line may be broken
Solution Approach 1:
The device incorporates a ratchet and pawl mechanism that provides mechanical feedback control. As the elastic line is tensioned, the ratchet allows incremental tightening while the pawl prevents over-tensioning, providing automatic feedback that stops the tightening process at the optimal point, eliminating the need for operator judgment and preventing elastic line breakage.
Solution Approach 2:
The device pre-sets the maximum tension limit through the ratchet mechanism design. Before the operator needs to judge the appropriate tension, the mechanical system has already established the safe tension threshold, preventing over-tightening and elastic line breakage through preliminary mechanical constraint.
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 self-tightening mechanism provides a more stable and effective ligation, reducing the risk of slippage and postoperative bleeding, with a smaller ulcer surface and improved tissue necrosis, enhancing treatment efficacy.
Implementation Method 1
an automatic tensioning mechanism that uses a compression spring to rapidly reduce the loop size at the front end
Implementation Method 2
block the blood supply of the hemorrhoid by the elastic retraction force of the apron
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A ligator setup method for automatically tightening an elastic line and a self-tightening elastic line ligator. The self-tightening elastic line ligator comprises: at least one piece of an elastic line (30) disposed along an outer wall of an outer barrel (22) of the ligator. A front end of the elastic line (30) forms a size-adjustable loop loopingly disposed on an outer wall of a front end of an inner barrel (21). A distal end of the elastic line (30) connects to a line-retracting auto-connector (80) of the ligator. The other end of the line-retracting auto-connector (80) connects, via a compression spring (90), to a self-tightening trigger (100). When retracting the distal end of the elastic line (30), the self-tightening trigger (100) loosens the connection thereof to the compression spring (90). The line-retracting auto-connector (80) retracts and tightens the elastic line (30) by means of a recoiling force of the compression spring (90), rapidly reducing the size of the loop at the front end of the elastic line (30). The self-tightening elastic line ligator provides, via the compression spring (90), and to the line-retracting auto-connector, a recoiling force for retracting and tightening, automatically tightening the elastic line (30) so as to rapidly reduce the size of the loop at the front end of the elastic line (30) to a minimum or close to zero, thereby achieving a tighter and more secure ligature of a target tissue.