Medical Instrument Jaw Alignment Features for Tolerance-Stable Fit

Solution Overview

Problem

Existing electrosurgical instruments face challenges in maintaining consistent and predictable fit between the end effector and shaft assembly, leading to undesirable component movement and inconsistent performance due to manufacturing variations.

Innovation Solution

The design incorporates specific features such as beams and ribs that ensure precise positioning and fixation of the end effector relative to the shaft assembly, including self-piloting mechanisms and hard stops to maintain consistent alignment and prevent unintended motion, ensuring predictable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If manufacturing tolerances are relaxed to ease production, then manufacturing cost and complexity are reduced, but component alignment precision and fit consistency deteriorate

Engineering Contradiction:

Improveease of manufactureVSAvoidcomponent alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent incorporates preliminary positioning features such as alignment ribs, datum surfaces, and guide pins that are built into the mold design before manufacturing. These features ensure that components like the end effector and shaft assembly are automatically aligned to precise positions during assembly, eliminating the need for post-manufacturing adjustment and ensuring consistent fit without requiring extremely tight manufacturing tolerances on individual parts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediary alignment elements including positioning ribs, guide surfaces, and intermediate fixtures that mediate between the end effector and shaft assembly. These intermediary features act as self-aligning mechanisms that compensate for normal manufacturing variations, ensuring precise relative positioning without requiring the mating surfaces themselves to have extremely tight tolerances.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If manufacturing tolerances are minimized to improve fit consistency, then component movement is reduced, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvefit consistencyVSAvoidmanufacturing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent incorporates preliminary positioning features such as alignment ribs, datum surfaces, and guide pins that are built into the mold design before manufacturing. These features ensure that components like the end effector and shaft assembly are automatically aligned to precise positions during assembly, eliminating the need for post-manufacturing adjustment and ensuring consistent fit without requiring extremely tight manufacturing tolerances on individual parts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent designs self-aligning features where the end effector and shaft assembly include built-in positioning mechanisms that automatically adjust and maintain precise alignment during assembly and operation. Features such as complementary guide surfaces, interference fits with tolerance compensation, and elastic positioning elements enable the components to self-correct minor misalignments without requiring complex external adjustment mechanisms or extremely tight manufacturing tolerances.

Inventive Principle:

Principle #25Self-service

3Reliability

If tighter manufacturing tolerances are applied to ensure consistent fit, then relative movement between components is minimized, but production time and cost increase

Engineering Contradiction:

Improvecomponent stabilityVSAvoidproduction time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent incorporates preliminary positioning features such as alignment ribs, datum surfaces, and guide pins that are built into the mold design before manufacturing. These features ensure that components like the end effector and shaft assembly are automatically aligned to precise positions during assembly, eliminating the need for post-manufacturing adjustment and ensuring consistent fit without requiring extremely tight manufacturing tolerances on individual parts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent designs self-aligning features where the end effector and shaft assembly include built-in positioning mechanisms that automatically adjust and maintain precise alignment during assembly and operation. Features such as complementary guide surfaces, interference fits with tolerance compensation, and elastic positioning elements enable the components to self-correct minor misalignments without requiring complex external adjustment mechanisms or extremely tight manufacturing tolerances.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20260047882A1Jaw features of medical instrument end effector

Publication Date: 2026.02.19 CILAG GMBH INTERNATIONAL

AI summary

An apparatus includes a body, a shaft assembly, and an end effector. The shaft assembly includes an inner guide having a laterally facing surface and a distally facing surface. The end effector includes a first jaw and a second jaw. The first jaw is movable toward and away from the second jaw. The second jaw includes a first proximally projecting beam. The first proximally projecting beam is positioned and configured to engage the laterally facing surface of the inner guide to thereby establish and maintain a predetermined angular position of the end effector relative to the shaft assembly. The first proximally projecting beam is further positioned and configured to engage the distally facing surface of the inner guide to thereby establish and maintain a predetermined longitudinal position of the end effector relative to the shaft assembly.