Hydraulic Orthopedic Joint With 3-Way Valve Volume Compensation
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Solution Overview
Problem
Existing orthopaedic device joints with hydraulic systems are costly to manufacture and require a large amount of space due to complex designs with multiple check valves and controllable valves, or they require high control effort and numerous parts.
Innovation Solution
A joint design using a throttle valve and a 3-way valve in parallel configuration, where the 3-way valve switches based on pressure differences to connect fluid lines with a compensating volume, reducing the number of components and eliminating the need for complex control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple check valves and controllable valves are used to connect the compensating volume to the hydraulic chambers, then the hydraulic functionality is ensured, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple valve functions into a single 3-way valve that can connect the compensating volume to either of the two hydraulic chambers. This single valve replaces what would traditionally require multiple check valves and controllable valves, thereby reducing device complexity while maintaining the necessary hydraulic functionality for volume compensation during joint movement.
Solution Approach 2:
The 3-way valve serves multiple functions: it acts as a directional control valve to connect the compensating volume to the appropriate hydraulic chamber, and simultaneously provides flow resistance control. This multi-functional design eliminates the need for separate dedicated valves for each function, reducing the overall number of components.
2Reliability
If multiple check valves and controllable valves are used to connect the compensating volume to the hydraulic chambers, then the hydraulic functionality is ensured, but the manufacturing cost increases
Solution Approach 1:
By merging multiple valve functions into a single 3-way valve, the patent reduces the number of parts that need to be manufactured, assembled, and quality-tested. This consolidation directly reduces manufacturing cost while maintaining the required hydraulic functionality for volume compensation.
3Adaptability or versatility
If two controllable valves are used to connect the compensating volume to each fluid line, then the hydraulic control is achieved, but the control effort and number of parts increase
Solution Approach 1:
The patent merges the functionality of two separate controllable valves into a single 3-way valve. This single valve can selectively connect the compensating volume to either fluid line, achieving the same hydraulic control adaptability with fewer parts and reduced control complexity.
4Device complexity
If a compact joint design is achieved by reducing the number of components, then the device size and cost are reduced, but the hydraulic control capability may be compromised
Solution Approach 1:
The 3-way valve is designed to perform multiple hydraulic control functions within a single component. It can connect the compensating volume to either hydraulic chamber, providing full adaptability for volume compensation during joint movement in both directions, while maintaining a compact component count.
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 achieves cost-effective manufacturing and compact size while maintaining hydraulic functionality, with adjustable damping resistance in different directions, and can accommodate volume fluctuations without additional mechanical or electrical control.
Implementation Method 1
the fluid lines present a flow resistance to the flowing fluid. The magnitude of this flow resistance determines, among other things, how quickly the fluid flows from one chamber to the other and thus how quickly the two joint components are articulated relative to each other for a given force. The flow resistance is therefore a measure of the damping of the joint's movement.
Implementation Method 2
the 3-way valve is designed in such a way that it is switched so that hydraulic fluid can flow from the fluid line with the lower pressure into the compensating volume and vice versa
Implementation Method 3
when the first joint part is pivoted relative to the second joint part, hydraulic fluid is directed from one hydraulic chamber to the other hydraulic chamber
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a joint for an orthopedic device. The joint has a first joint part, a second joint part which is pivotally arranged on the first joint part about a pivot axis, and a hydraulic system which has a first hydraulic chamber (4) with a first fluid line (16) and a second hydraulic chamber (6) with a second fluid line (18). The two fluid lines (16, 18) are connected together, wherein when the first joint part is pivoted relative to the second joint part, hydraulic fluid is guided from one hydraulic chamber (4, 6) into the other hydraulic chamber (6, 4), and the fluid lines (16, 18) are connected by means of a throttle valve (20) and a 3-way valve (22) which operate in parallel to each other. The third outlet (28) of the 3-way valve (22) is connected to a compensation volume (30), and the 3-way valve (22) is designed to be connected such that hydraulic fluid can flow from the fluid line (16, 18) with the lower pressure into the compensation volume (30) and vice versa.