Collet Chuck Tapered Surface for Stable Stent Clamping
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Solution Overview
Problem
Existing stent delivery systems face instability in clamping guide catheters due to inconsistent tightening forces, which can lead to inadequate fixation or release of stents during procedures.
Innovation Solution
A stent delivery system featuring a collet chuck mechanism with a chuck nut and collet that includes distinct regions for varying contact points to achieve a consistent and appropriate tightening force, ensuring stable clamping and release of the guide catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the rear outer cylinder is screwed into the front outer cylinder to tighten the wire main body, then the tightening force increases, but the tightening force becomes excessively large when screwed too much and insufficient when screwed insufficiently, leading to unstable clamping
Solution Approach 1:
The chuck nut is designed with a tapered inner circumferential surface that has different contact characteristics at different locations. The taper angle creates a progressive tightening effect where the contact force is distributed along the taper, providing controlled and consistent clamping force rather than abrupt excessive force.
Solution Approach 2:
The patent changes the geometric parameters of the chuck nut by introducing a specific taper angle on its inner circumferential surface. This parameter modification transforms the tightening mechanism from direct screwing force transmission to a distributed tapered contact force, ensuring stable and appropriate tightening force regardless of slight variations in screwing depth.
2Force
If the collet is allowed to approach the center axis significantly to tighten the guide catheter, then the clamping force increases, but excessive bending occurs leading to potential damage or instability
Solution Approach 1:
The tapered surface on the chuck nut creates localized contact points on the collet at different heights. This distributed contact approach allows the collet to be tightened gradually from the base upward, preventing excessive bending at any single location while maintaining adequate clamping force.
Solution Approach 2:
The tapered geometry of the chuck nut provides a cushioning effect by distributing the tightening force over a gradual transition rather than an abrupt contact. This prevents sudden excessive forces that would cause collet bending or damage, ensuring smooth and controlled deformation.
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 system provides a stable and controlled clamping force, ensuring reliable deployment and fixation of stents, even with manufacturing variations, by using a collet chuck with a first region for initial contact and a second region for maintaining the clamping force without excessive bending.
Implementation Method 1
an inner circumferential surface of the chuck nut facing a center axis of the guide catheter includes a first region that tightens the collet to make the collet to approach the center axis as coming into contact with the collet
Implementation Method 2
a second region being at an opposite side of the collet with respect to the first region, wherein an approaching amount of the collet to the center axis as the second region coming into contact with the collet while approaching the collet to make the collet to approach the center axis is smaller than that in the first region
Data Source
AI summary
A stent delivery system includes a stent; a pusher catheter disposed at a proximal-end side thereof; and a collet chuck disposed at the proximal-end side of the pusher catheter. The collet chuck includes a collet disposed along an outer circumference of a guide catheter; and a chuck nut provided to be relatively advanceable and retractable with respect to the collet and into which the guide catheter is insertable, and an inner circumferential surface of the chuck nut facing a center axis of the guide catheter includes a first region tightens the collet to make the collet to approach the center axis as coming into contact with the collet while approaching the collet; and a second region being at an opposite side of the collet with respect to the first region for making an approaching amount of the collet to be smaller than that in the first region.