Eccentric Cam Tool Tip for Compact Medical Instrument
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Solution Overview
Problem
Existing medical instruments with hollow shafts require complex and large structural configurations to achieve the necessary degrees of freedom for tool tips, often necessitating high forces for pivoting and increasing the instrument's diameter and length, which limits dexterity and versatility.
Innovation Solution
A medical instrument design featuring a tool tip mounted via a link element that can be bent relative to the shaft's longitudinal axis, with a rotatable mount and an eccentrically positioned actuating element, allowing for compact construction and reduced force requirements, while maintaining full mobility and dexterity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a complex assembly of joints and force transmission elements is used to achieve different degrees of freedom for the tool tip, then the tool tip mobility is improved, but the device complexity and structural size increase
Solution Approach 1:
The cam element combines multiple functions into a single component: it enables tool tip angulation relative to the shaft, allows rotation about the shaft's longitudinal axis, and provides the pivot point for jaw movement. This merging of functions reduces the number of separate joints and force transmission elements while maintaining full tool tip mobility
Solution Approach 2:
The cam element serves multiple purposes simultaneously: it acts as a pivot point for angulation, a bearing surface for rotation, and a guide for the pull/push element. This multi-functionality eliminates the need for separate mechanical components for each degree of freedom, simplifying the overall device structure
2Volume of moving object
If pivot points for swiveling the tool tip are located close together, then the structural size is reduced, but a relatively large force is required to swivel the tool tip
Solution Approach 1:
The cam element utilizes an eccentric circular geometry where the distance from the rotation axis to the cam surface varies continuously. This curved geometry provides a mechanical advantage that reduces the force required for swiveling while maintaining a compact structure, as the eccentric design allows force application at optimal leverage points throughout the range of motion
3Ease of operation
If the diameter of the instrument shaft and tool tip are minimized, then dexterity is improved, but space for mechanisms like the pull/push element is limited
Solution Approach 1:
The pull/push element is mounted eccentrically within the tool tip rather than centrally, creating an asymmetric arrangement. This eccentric mounting optimizes the distribution of internal space, allowing the mechanism to fit within a smaller overall diameter while maintaining full functionality. The asymmetric design enables the pull/push element to actuate the jaw pivot point efficiently without requiring excessive radial space
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 design ensures maximum dexterity and compactness by allowing the tool tip to be angled and rotated with reduced force, maintaining full mobility and minimizing the instrument's diameter and length, thus enhancing usability in endoscopic surgery.
Implementation Method 1
the tool tip is mounted at the distal end of the shaft in a way that allows it to be angled relative to the longitudinal axis of the shaft via a cam element
Implementation Method 2
the tool tip is mounted proximally in the cam element in a way that allows it to be rotated about the longitudinal axis of the shaft or about the longitudinal axis of the tool tip via a hollow pin arranged eccentrically to the longitudinal axis of the shaft or the longitudinal axis of the tool tip
Data Source
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AI summary
The invention relates to a medical instrument with a hollow shaft (2), at the proximal end of which a handle (3) is arranged and at the distal end of which a tool (4) with two jaw parts (5, 6) is arranged, at least one jaw part (5 or 6) of which is pivotable relative to the other jaw parts (6 or 5), wherein a distal end region of the shaft (2) supporting the tool (4) is designed as a tool tip (8) that can be angled relative to the longitudinal axis (7) of the shaft (2) and the tool tip (8) is rotatable about the longitudinal axis (7) of the shaft (2) or about the longitudinal axis (7a) of the tool tip (8), wherein the rotation of the tool tip (8) about the longitudinal axis (7) of the shaft (2) or about the longitudinal axis (7a) of the tool tip (8)The movement of the longitudinal axis (7a) of the tool tip (8) is effected via a first actuating element (10) rotatably mounted in the hollow shaft (2), which is in operative connection with the handle (3) on the proximal side, and the deflection of the tool tip (8) is effected via a second actuating element (11) axially displaceable in the hollow shaft (2) and in operative connection with the handle (3) on the proximal side, and the at least one pivotable jaw part (5 or 6) of the tool (4) is adjustable between a closed and an open position via a pull/push element (9) axially displaceable in the tool tip (8), which is in operative connection with the handle (3) on the proximal side.In order to create a medical instrument that ensures full mobility of the tool tip (8) while maintaining a simple and compact design, the invention proposes that the pull/push element (9) for actuating the at least one pivotable jaw part (5 or 6) is mounted eccentrically in the tool tip (8) parallel to the longitudinal axis (7) of the shaft (2) or the longitudinal axis (7a) of the tool tip (8).