Medical Forceps Play-Free Transmission via Articulated Lever
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Solution Overview
Problem
Existing medical forceps suffer from non-free play movement issues in their force transmission mechanisms, leading to incomplete alignment and restricted movement ranges due to circular movements and articulation point misalignments, which limit their effectiveness in minimally invasive surgeries.
Innovation Solution
A medical forceps design featuring a force transmission mechanism with a linearly guided slide in a sliding bearing and an articulated lever connecting the movable grip part to the slide, ensuring axial movement and minimizing play, along with a separate, flush-fitting sliding bearing for improved guidance and contamination prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the movable grip part is connected directly to the slide with an articulated connection, then the device complexity is reduced, but the slide undergoes circular movement instead of linear movement, causing play and restricting the movement range
Solution Approach 1:
The patent introduces an articulated lever as an intermediary element between the movable grip part and the slide. This lever has one end articulated to the movable grip part and the other end articulated to the slide, serving as a mediator that converts the circular movement of the grip part into linear movement of the slide, thereby eliminating play while maintaining mechanical simplicity
Solution Approach 2:
The articulated lever changes the movement dimension from circular (angular) to linear by utilizing the lever's rotation about its own axis. This dimensional transformation allows the slide to move purely axially without circular components, resolving the play issue while keeping the mechanism simple
2Device complexity
If the articulation point of the force transmission element undergoes circular movement, then the force transmission mechanism is simpler, but additional transverse movement occurs causing play and misalignment
Solution Approach 1:
The articulated lever acts as a mediator that decouples the circular movement of the grip part from the linear movement requirement of the slide. By articulating the lever to both components, it transforms the motion trajectory, ensuring the force transmission element moves only axially without transverse circular components, thus achieving precise alignment
Solution Approach 2:
The lever mechanism changes the motion from two-dimensional circular movement to one-dimensional linear movement by utilizing rotational motion about the lever's axis. This dimensional reduction eliminates transverse movements and ensures precise axial alignment of the force transmission element
3Reliability
If the slide is guided with an exact fit in a sliding bearing, then the movement precision is improved, but the device complexity increases
Solution Approach 1:
The sliding bearing is extracted as a separate, independent component from the main force transmission mechanism. This allows the bearing to be optimized specifically for guiding the slide with exact fit, while the rest of the mechanism remains simple. The bearing can be manufactured separately and assembled into the handle, maintaining precision without complicating the overall design
Data Source
AI summary
A medical forceps has a shaft, a handle at the proximal end of the shaft, which handle has at least one movable grip part which is pivotable about a pivot axis, at least one movable tool at the distal end of the shaft, and a force transmission element, which runs in the direction of the longitudinal axis of the shaft and is axially movable and with one end is in operative connection with the at least one movable tool and with the other end is in operative connection with the at least one movable grip part. The force transmission element is connected to a slide which is guided linearly with an exact fit in a sliding bearing and is axially movable in the direction of the force transmission element, the slide being connected to the movable grip part by means of an articulated lever, which is articulated with one end on the slide and with another end on the movable grip part.