Surgical Stapler Ejector Mechanism Reduces Complexity
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Solution Overview
Problem
Existing surgical stapling devices require complex and costly kick-off mechanisms with spiral springs and additional components, leading to mechanical inefficiencies and potential contamination risks due to wear and tissue contact.
Innovation Solution
A simplified kick-off mechanism featuring an arrowhead-shaped ejector element with obliquely slanting front edges and a rear elastically resilient area, eliminating the need for a separate spring and reducing the risk of contamination by ensuring a linear motion of the ejector element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex kick-off mechanism with spiral springs and separate push rod is used, then the staple can be detached from the anvil, but the device complexity and manufacturing cost increase
Solution Approach 1:
The ejector element integrates multiple functions into a single component: it combines the kick-off function (detaching staple from anvil) and the push rod function (returning upper die to starting position) that were previously separate components. The flattened rear end of the ejector element acts as both the spring abutment and the actuator for returning the upper die, eliminating the need for a separate push rod and reducing mechanical complexity
Solution Approach 2:
The spiral spring is extracted from the system and replaced by utilizing the elastic properties of the ejector element itself. The rear portion of the ejector element is designed to be elastically deformable, serving as a linear spring that provides the necessary force without requiring a separate spiral spring component
2Reliability
If the kick-off tongue is bent downwards to detach staple, then the staple can be ejected, but the risk of contamination increases due to tissue contact
Solution Approach 1:
Instead of bending the ejector element downwards to contact the staple legs (which risks tissue contact), the invention inverts the approach: the ejector element moves linearly forwards with its front edge contacting the staple cross bar from below. The staple is detached by pushing against the cross bar rather than by bending downwards, eliminating the contamination risk while achieving the same ejection function
3Ease of operation
If a separate push rod is used to return upper die to starting position, then the mechanism can be actuated, but the manufacturing cost and assembly complexity increase
Solution Approach 1:
The flattened rear end of the ejector element serves dual purposes: it acts as the abutment for the linear spring and simultaneously functions as the push rod that returns the upper die to its starting position. This integration eliminates the need for a separate push rod component, reducing manufacturing steps and assembly complexity while maintaining the full actuation function
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 reduces mechanical complexity, minimizes manufacturing costs, and prevents contamination by maintaining the staple's position during application and ensuring effective ejection without bending the ejector tip, thus enhancing the stapling process's efficiency and reliability.
Implementation Method 1
The entire stack of staples is spring-loaded in the staple magazine so that the stack of staples is forced towards a staple outlet of the magazine
Implementation Method 2
an elastically resilient area (166) in a rear section of the ejector element (16)
Data Source
AI summary
A surgical stapling device for applying staples in a layer of tissue. A staple magazine is arranged in a device body and contains a plurality of spring loaded, stacked staples. A triggering element moves from a ready position to an actuation position causing an upper die to pick up a staple at an outlet of the staple magazine, to bend the staple feet inwards, and to fold, on an anvil engaging between the staple feet, the ends of a staple cross bar so as to form staple legs. A flat, spring-loaded tongue ejector element extends beneath the anvil. The ejector element is displaced against its direction of transport when the triggering element is moved from a readiness position into the actuation position, and is displaced in its direction of transport when the triggering element returns to the ready position so as to push the applied staple from the anvil.