Sterile Unit Conical Coupling for Robotic Surgery Alignment
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Solution Overview
Problem
Existing sterile units for surgical robotic systems face difficulties in easy connection and alignment of transmission elements with instrument drive units, leading to potential jamming and prolonged alignment processes due to frictional issues and material combinations.
Innovation Solution
The sterile unit employs coaxially aligned conical areas on the transmission element and through-opening for positive and non-positive contact, generating increased friction torque and acting as a guide to prevent jamming, while snap hooks facilitate assembly and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional transmission elements with flat surfaces are used, then manufacturing is simple, but alignment difficulty and jamming risk increase
Solution Approach 1:
The transmission element incorporates a conical area instead of a flat surface, creating a curved geometry that provides self-aligning capability. The conical shape guides the transmission element into proper alignment with the drive during insertion, eliminating the need for precise manual alignment while maintaining manufacturing simplicity.
2Power
If friction between transmission element and drive is increased for better torque transmission, then torque transmission improves, but alignment process is prolonged
Solution Approach 1:
The conical area creates a wedge effect during insertion that generates high friction torque automatically. The friction coefficient between the conical area and drive is designed to be high (≥0.5), which provides strong self-locking and torque transmission during the alignment process, preventing prolonged alignment while ensuring reliable power transmission.
Solution Approach 2:
The patent specifies a minimum friction coefficient of 0.5 between the conical area and drive, and defines a specific cone angle range (5°-15°) to optimize the balance between self-locking capability and alignment speed. These parameter optimizations ensure rapid alignment without excessive friction resistance.
3Manufacturing precision
If the transmission element is held firmly in the through-opening, then positioning accuracy improves, but removal and repositioning become difficult
Solution Approach 1:
The base is divided into two functional zones: a conical area for firm positioning and torque transmission, and a cylindrical area for easy removal and repositioning. The transmission element engages the conical area during operation for precise positioning, but can be easily removed by pulling it out of the cylindrical area, enabling quick repositioning if needed.
4Ease of manufacture
If conventional flat contact surfaces are used, then manufacturing is easy, but self-locking capability is insufficient
Solution Approach 1:
The conical area replaces the flat contact surface, creating a wedge-shaped interface that generates self-locking through geometric constraint. The cone angle (5°-15°) is specifically designed to provide adequate self-locking capability while maintaining manufacturability through standard machining processes.
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
This design enhances the ease of connecting transmission elements, reduces jamming risks, and optimizes self-locking for efficient torque transmission, improving the alignment process and reducing manufacturing costs.
Implementation Method 1
generating an increased friction torque which acts on the transmission element
Implementation Method 2
causing a circumferential elastic deformation of the transmission element and of the base at the conical area, the merging force acting at an angle to the surface
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
The invention relates to a sterile unit (10) for sterilely connecting an instrument drive unit (20) to a surgical instrument (30), comprising a base (11) with at least one circular through-opening, wherein a transmission element (12) is arranged in the through-opening, which is rotatably mounted about an axis of rotation (A) and is axially movable in the direction of the axis of rotation in a predetermined range of movement between a first and a second end position, and a first fastening mechanism with which the sterile unit (10) is connected to the instrument drive unit (20), and a second fastening mechanism (14) with which the sterile unit (10) is connected to the instrument (30).To improve the coupling between the sterile unit (10) and the instrument drive unit (20), the transmission element (12) on a circumferential surface and the through-opening on a passage wall each have a coaxially aligned and complementary conical area which are in positive and force-locking contact in the first end position, so that a rotation of the transmission element (12) about the axis of rotation relative to the base (11) is inhibited.