Spring Clip Locking Mechanism for Circular Stapler Knife Carrier
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Solution Overview
Problem
Conventional circular stapling devices lack a reliable mechanism to retain the knife carrier in a retracted position after use, posing a safety risk to clinicians during tissue donut removal and manipulation.
Innovation Solution
A reload assembly with a spring clip mechanism that locks the knife carrier in a retracted position using a locking tang and engagement portion, preventing advancement until the anvil assembly is attached and the device is in a clamped position, ensuring the knife remains recessed and safe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the knife carrier is allowed to move freely for tissue donut removal, then the tissue donut can be accessed, but the cutting edge may be exposed creating a safety hazard
Solution Approach 1:
The spring clip is pre-configured with a locking tang that automatically engages with the cutout in the knife carrier body, establishing a locked state before any tissue removal operation begins. This preliminary locking action ensures the knife carrier remains in a safe retracted position during all subsequent manipulation and disposal activities.
Solution Approach 2:
The spring clip acts as an intermediary safety mechanism between the knife carrier and the clinician. It provides a physical barrier that prevents direct access to the cutting edge while still allowing the tissue donut to be removed through the cavity, thus mediating between operational needs and safety requirements.
2Object-affected harmful factors
If a locking mechanism is added to retain the knife carrier, then safety is improved, but device complexity increases
Solution Approach 1:
The spring clip is designed as a self-servicing locking mechanism that automatically engages and disengages based on the operational state. The resilient nature of the spring clip allows it to self-lock during storage and transport, and self-unlock when the anvil assembly is properly attached, eliminating the need for additional control systems or complex actuation mechanisms.
Solution Approach 2:
The spring clip utilizes changes in its physical state (compressed vs. relaxed) to control the locking function. When compressed, it engages the locking tang with the cutout; when relaxed due to anvil assembly attachment, it releases the lock. This parameter-based control simplifies the overall device architecture by using physical state changes rather than complex mechanical or electronic control systems.
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 effectively minimizes the risk of injury to clinicians by maintaining the knife in a retracted position until the anvil assembly is attached, ensuring the cutting edge is not exposed during reload assembly disengagement and tissue donut removal.
Implementation Method 1
The spring clip is resilient and is movable from a first position in which the engagement portion extends across the central bore of the inner housing portion and the locking tang is received within the cutout of the knife carrier to obstruct advancement of the knife carrier
Data Source
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AI summary
A reload assembly a shell housing, a staple cartridge, a pusher assembly, a knife carrier, an annular knife, and a spring clip. The shell housing includes an inner housing portion that defines a central bore. The knife carrier includes a body defining a longitudinal axis and a cutout and is movable within the shell housing between advanced and retracted positions. The spring clip is supported on the inner housing portion of the shell housing and has a locking tang and an engagement portion. The spring clip is movable from a first position in which the locking tang is received within the cutout of the knife carrier to obstruct advancement of the knife carrier to a second position in which the locking tang is removed from the cutout of the knife carrier.