Microscope Linear Drive with Spacing Member for Precision
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Solution Overview
Problem
Existing linear drives for microscopes face challenges in achieving high accuracy and load-carrying capacity while minimizing noise and wear, particularly when moving functional units like stages or nosepieces over long distances, due to small spindle pitches and wear-prone components.
Innovation Solution
A linear drive design featuring a rotatable first moveable member and a second moveable member connected to the functional unit, with a spacing member maintaining constant spacing between them, converting rotary motion into linear motion through positive locking principles, allowing precise and reproducible positioning and supporting heavy loads with reduced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spindle drive with small spindle pitch is used to move the slide in the sub-μm range, then positioning precision is improved, but the time required to move the slide over a long distance increases and noise emissions increase
Solution Approach 1:
The drive system is divided into two independent parts: a rotary drive for high-precision positioning and a spacing member for long-distance linear movement. The spacing member acts as a mechanical lever that converts small rotational displacements into large linear displacements, eliminating the need for a long spindle while maintaining precision.
Solution Approach 2:
The invention transitions from a unidimensional linear spindle drive to a two-dimensional system combining rotary motion (for precision) and linear translation (for distance). The spacing member creates a mechanical advantage that operates in a different dimensional space, allowing independent optimization of precision and travel distance.
2Measurement precision
If a spindle drive with small spindle pitch is used, then positioning precision is improved, but wear on contact surfaces increases
Solution Approach 1:
The invention extracts the wear-prone spindle and spindle nut contact surfaces from the system. Instead of using a spindle drive, the patent employs a rotary drive combined with a spacing member that maintains constant distance, eliminating the need for continuous sliding contact and associated wear problems.
Solution Approach 2:
The traditional spindle-mechanical contact system is replaced with a spacing member-based mechanism that uses geometric constraints rather than friction-based force transmission. This substitution eliminates wear by removing the sliding contact interface while maintaining the necessary positional control.
3Reliability
If piezo elements are used to move the slide, then wear resistance is improved, but the stroke is limited to approximately 1 mm
Solution Approach 1:
The spacing member is designed to be rotatable about an axis, transforming a static 1mm stroke limitation into a dynamic system where the effective stroke length can be extended through rotational movement. The constant spacing constraint allows the mechanism to achieve large linear displacements from small rotational angles.
Solution Approach 2:
The invention moves from linear piezoelectric actuation to rotational mechanical actuation. By using the rotational degree of freedom of the spacing member, the system achieves extended linear stroke length while maintaining wear resistance, effectively operating in a different dimensional space.
4Measurement precision
If ultrasonic motors are used to achieve high accuracy and speed over long distances, then positioning precision and speed are improved, but load-carrying capacity decreases due to frictional connection
Solution Approach 1:
The friction-based ultrasonic motor is replaced with a spacing member mechanism that uses geometric constraints and rigid body mechanics. This substitution eliminates frictional force limitations while maintaining high positioning precision through the constant spacing constraint, enabling both high speed and high load-carrying capacity.
Data Source
AI summary
A linear drive for moving a functional unit of a microscope is provided. The linear drive includes a first moveable member that is rotatable about an axis of rotation and fixed with respect to linear movement along the axis of rotation; a second moveable member that is connected to the functional unit, fixed against a rotation about the axis of rotation, and moveable along the axis of rotation; and a spacing member engaged with the first moveable member at a first point and the second moveable member at a second point, and configured to maintain a constant spacing between the first point of the first moveable member and the second point of the second moveable member.