Surgical Quick Connect Interface with 90-Degree Ball Bearing Retention
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Solution Overview
Problem
Existing quick connect interfaces in surgical instruments, such as the AO-style interface, fail to securely retain replaceable tools due to axial and lateral play, and are costly to manufacture to precise tolerances, often requiring expensive wire-EDM processes.
Innovation Solution
An improved quick connect interface with ball bearings positioned 90 degrees apart radially, a spring-loaded sliding sleeve, and a camming ramp with a double-plateau profile, which urges the ball bearings into holes to engage the shaft's groove, reducing play and allowing for minor variations, and a slot for the AO flat that can be milled inexpensively without wire-EDM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ball bearings are positioned radially about 180 degrees apart and held by straight walled portions, then the shaft is retained in the interface, but substantial axial and lateral play occurs and the fit is sloppy
Solution Approach 1:
The patent positions ball bearings at 90 degree intervals instead of 180 degrees, creating an asymmetric arrangement that provides more uniform radial support. This asymmetric positioning eliminates the sloppy fit and excessive play while maintaining secure tool retention.
Solution Approach 2:
The patent replaces fixed straight walled portions with a spring-loaded sleeve that dynamically adjusts to accommodate variations in shaft groove diameters. The spring mechanism provides adaptive retention, maintaining precise fit across different replaceable tools while preventing excessive play.
2Manufacturing precision
If wire-EDM is used to form the AO flat through the inner cavity, then precise tolerances are achieved, but manufacturing cost increases
Solution Approach 1:
Instead of forming the AO flat through the inner cavity using expensive wire-EDM, the patent inverts the approach by forming the AO flat on the outer surface of the body where it is easily accessible to conventional milling tools. This eliminates the need for costly wire-EDM while achieving the required precise tolerances.
Solution Approach 2:
The patent replaces the complex wire-EDM process with simple conventional milling operations. By repositioning the AO flat formation to the outer surface, standard mechanical milling tools can achieve precise tolerances without the high cost and complexity of wire-EDM.
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 solution provides a secure, stable connection with reduced play and eliminates the need for costly wire-EDM, enabling secure tool retention and cost-effective manufacturing.
Implementation Method 1
A spring-loaded sliding sleeve may surround a portion of the body and slide from an unlocked position to a locked position
Implementation Method 2
the ball bearings are urged by a camming ramp formed in the sleeve into the holes
Implementation Method 3
The ball bearings may engage a groove formed in the end of the shaft
Implementation Method 4
The pressure applied by the ball bearings may urge the shaft of the replaceable tool towards the side of the inner cavity of the body that includes the AO flat
Data Source
AI summary
In one embodiment, a quick connect interface for a surgical instrument includes a body having an inner cavity that includes a flat. Two or more ball bearings are each disposed in a respective hole in the body. A sleeve is slideable along the body. The sleeve includes a camming ramp that urges the two one or more ball bearings to partially extend through the holes into the inner cavity when the sleeve is in a locked position. The two or more ball bearings are positioned to, when the shaft of the replaceable tool is disposed in the inner cavity, urge the shaft to a side of the inner cavity that includes the flat. The ball bearings may be positioned radially about a central axis of the body substantially 90 degrees apart. The camming ramp may include at least one plateau that prevents unintentional release of the shaft.