Oscillating Microtome Flexure Drive Eliminates Backlash
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Solution Overview
Problem
Conventional oscillating microtomes suffer from imprecise oscillatory motion due to parasitic error motions and backlash, leading to imprecise section thicknesses and tissue damage, with limitations in frequency and magnitude of oscillations due to friction and guide rail imperfections.
Innovation Solution
A microtome with a flexure drive system comprising a primary flexure mechanism and a secondary flexure mechanism that decouples unwanted motions, allowing the blade to oscillate transversely while maintaining stiffness in the desired direction, eliminating the need for guide rails and reducing friction-induced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an articulated arm or guide rail system is used to drive blade oscillation, then the microtome can achieve oscillating motion, but parasitic error motions and backlash occur leading to imprecise section thicknesses
Solution Approach 1:
The patent replaces the traditional articulated arm or guide rail mechanical system with a magnetic field-based驱动 system. A permanent magnet attached to the blade assembly interacts with an electromagnetic coil, eliminating mechanical joints and guide rails that cause backlash and parasitic motions. This substitution of mechanical drive with electromagnetic drive achieves precise blade oscillation without the drawbacks of mechanical linkage systems.
2Speed
If guide rails are used to guide blade motion, then oscillating motion is achieved, but friction between the spring/arm and stationary rail limits upper frequency and magnitude of oscillations
Solution Approach 1:
The patent eliminates the guide rail mechanical guidance system and replaces it with a magnetic field-based驱动 system. The electromagnetic coil and permanent magnet arrangement provides contactless drive, removing the friction between moving and stationary components that limited oscillation frequency and magnitude in traditional guide rail systems.
3Measurement precision
If an articulated arm with joints is used, then oscillating motion is achieved, but backlash in the joint introduces higher order harmonics and parasitic motion along orthogonal axes
Solution Approach 1:
The patent replaces the articulated arm mechanical linkage with an electromagnetic驱动 system using a permanent magnet and coil. This eliminates joints and mechanical connections that produce backlash, thereby removing the source of higher order harmonics and parasitic orthogonal motions while simplifying the overall mechanical structure.
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 approach results in higher precision, reduced tissue damage, and improved section quality, enabling thinner sections and better imaging, with increased robustness, manufacturability, and longer instrument life.
Implementation Method 1
a first flexure configured to support and guide the blade, the first flexure configured to be compliant in the transverse direction while being stiff in the cut direction
Implementation Method 2
A second flexure operatively engaged at one end portion with the first flexure, is configured for being stiff in the transverse direction while being compliant in the cut direction
Implementation Method 3
The other end portion of the second flexure is rotatably engaged by an eccentric driven by a rotatable actuator, which oscillates the blade in the transverse direction
Data Source
AI summary
A microtome method and apparatus includes a microtome blade configured to oscillate in a direction transverse to a direction of advancing a cut, and a first flexure to support and guide the blade. The first flexure is compliant in the transverse direction while being stiff in the cut direction. A second flexure operatively engaged at one end portion with the first flexure, is stiff in the transverse direction while being compliant in the cut direction. The other end portion of the second flexure is rotatably engaged by an eccentric driven by a rotatable actuator, which oscillates the blade in the transverse direction while effectively isolating non-transverse motion from the blade. The second flexure is configured to move independently of any guides or other stationary objects during oscillation.