Orthopedic Hinge With Adjustable Spring Resistance
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Solution Overview
Problem
Existing knee braces do not allow for adjustable resistance to hinge motion without changing parts, and they lack the ability to easily adjust the angle at which resistance is applied, which can lead to uncomfortable jarring and poor compliance with rehabilitation guidelines.
Innovation Solution
A motion controlling hinge for orthopedic braces that includes a hinge plate, spring member, and pivotable arms, with a cam that can be switched between 'ON' and 'OFF' positions to control the resistance, allowing for adjustable force and angle of resistance application, and a method to adjust the resistive force by manipulating a switch or fulcrum position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid extension stop is used to limit knee extension, then the knee extension angle is controlled, but the wearer experiences jarring and discomfort at maximum extension
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a resilient member (spring) that gradually decelerates the knee extension motion before the extension stop is reached. This cushioning action occurs in advance of the hard stop, transforming the abrupt rigid termination into a progressive, comfortable deceleration that eliminates jarring while maintaining reliable extension angle control.
Solution Approach 2:
The patent changes the physical parameter of the stopping mechanism from rigid to resilient. By replacing the rigid extension stop with a spring-based deceleration mechanism, the system transforms the nature of the force application from instantaneous and harsh to gradual and comfortable, thereby improving wearer comfort while maintaining extension control.
2Reliability
If the extension stop is made rigid to ensure reliable extension limitation, then extension control is achieved, but patient compliance decreases due to discomfort
Solution Approach 1:
The resilient member provides beforehand cushioning that gradually reduces the speed of extension motion before the extension stop engages. This cushioning effect makes the extension limitation process comfortable and acceptable to patients, thereby improving compliance while maintaining reliable extension angle control through the same mechanism.
3Device complexity
If fixed hinge parts are used, then the structure is simple, but adjustment of resistance force and angle requires part interchange
Solution Approach 1:
The patent applies dynamics by making the hinge system adjustable without requiring part interchange. The resilient member's properties (force constant, pre-compression) and the extension stop position can be modified by adjusting existing components rather than replacing entire hinge parts. This dynamic adjustability allows customization of resistance force and angle while maintaining relatively simple hinge structure.
Solution Approach 2:
The patent enables parameter changes by allowing modification of the spring's force characteristics and pre-compression level, as well as the extension stop position, without changing the fundamental hinge structure. These parameter adjustments provide versatility in resistance control while keeping the device complexity low.
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 a comfortable and adjustable resistance to knee extension, reducing jarring and improving patient compliance with rehabilitation programs by allowing for customizable resistance levels and angles without the need to interchange hinge parts.
Implementation Method 1
a spring member, and first and second arms pivotably secured to the hinge plate. An actuator is secured to the second arm. As the arms pivot in a first direction such that an angle between them increases, once the arms reach a desired extension angle, the spring member exerts a force on the actuator tending to bias the second arm in a second direction opposite the first direction.
Data Source
AI summary
A motion controlling hinge for an orthopedic brace is provided. The hinge includes an actuator secured to one arm, and at least one spring member. As the arm with the actuator pivots in a first direction, at a predetermined flexion angle the actuator applies a force to the spring member, causing the spring member to flex. The spring member exerts a force on the actuator tending to bias the actuator away from the spring member, and tending to bias the arm in a second direction opposite the first direction. In one embodiment, the spring member comprises a plurality of flat bar leaf springs. A movable fulcrum enables adjustment of a force exerted by the spring member on the actuator. A variety of differently sized adapters are securable to the actuator. The size of the adapter determines the flexion angle at which the spring member first exerts force on the actuator. In some embodiments, the hinge includes an “ON”/“OFF” switch that enables a user to disengage biasing force provided by the spring member. When the switch occupies the “OFF” position, the hinge is freely pivotable to a maximum extension angle.