Frictionless Orthopedic Simulator Load Actuators
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Solution Overview
Problem
The accuracy of orthopedic device testing is compromised by friction in force actuators, leading to inconsistent results across multiple test stations due to varying friction levels in different actuators, affecting the application of precise loads and motions to test specimens.
Innovation Solution
The development of an orthopedic simulator with integral load actuators featuring a housing, axially slideable piston, hydrostatic bearings, and hydraulic fluid ports, which enable substantially frictionless extension and retraction, ensuring consistent and accurate loading across multiple test stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional force actuators with seals are used to apply loads to test specimens, then the actuators can provide mechanical force, but friction from seals creates variability in friction levels across different actuators, leading to inconsistent test results
Solution Approach 1:
The patent applies hydraulic principles by using fluid pressure to support the piston and eliminate friction. The actuator uses a piston that floats on hydraulic fluid rather than traditional mechanical seals, allowing the piston to move freely without friction while still providing controlled force application to test specimens.
Solution Approach 2:
The patent replaces the traditional mechanical seal-based actuator system with a hydraulic fluid-based system. Instead of using mechanical contacts that create friction, the system uses fluid pressure to support and move the piston, substituting mechanical friction with hydraulic support.
2Measurement precision
If actuators with mechanical seals are used to provide force, then the actuators can maintain structural integrity, but the seals create friction that reduces accuracy in applying specific desired loads
Solution Approach 1:
The patent uses hydraulic fluid pressure to support the piston and eliminate friction during force application. The fluid provides a frictionless medium that allows the piston to move and apply loads with high precision, replacing mechanical seals that create friction and reduce accuracy.
Solution Approach 2:
The patent changes the physical state and properties of the actuator system by transitioning from solid mechanical contacts to fluid-based support. This parameter change eliminates friction by using the incompressible nature of hydraulic fluid to provide continuous, frictionless support to the piston during load application.
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
The solution provides accurate and repeatable forces to test specimens by minimizing friction effects, ensuring consistent loading across all test stations and enhancing the accuracy and speed of orthopedic device testing.
Implementation Method 1
hydrostatic bearings that float the piston; and hydraulic fluid ports in the piston housing. Hydraulic fluid pressure in the hydraulic fluid ports control substantially frictionless extension and retraction of the piston with respect to the housing
Data Source
AI summary
An orthopedic simulator is provided with a plurality of test stations for each holding a test specimen. A plurality of load actuators are provided, with a respective load actuator for each of the test stations. The load actuators are substantially frictionless and configured to apply loads to the test specimens at the test stations.