Assistive Sit-to-Stand Device With Spring Energy Storage
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Solution Overview
Problem
Conventional sit-to-stand devices for physically impaired individuals face challenges in effectively lifting users due to insufficient potential energy from trunk weight, leading to potential falls and reliance on bulky, expensive external energy sources.
Innovation Solution
A sit-to-stand device featuring a slidable seat apparatus, lift apparatus, and power apparatus comprising wrap springs and gas springs, which store and release potential energy to raise the user, forming a 3D quadrilateral structure to minimize torque and facilitate standing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional power apparatus stores potential energy from seated trunk weight to lift the user, then the device can assist standing up, but the potential energy from trunk weight is insufficient to lift the same trunk weight
Solution Approach 1:
The patent introduces a counterweight mechanism that includes a counterweight member and a counterweight spring. The counterweight member is positioned to balance part of the trunk weight, reducing the net weight that the power apparatus must lift. The counterweight spring stores and releases energy to assist in the lifting process, effectively creating a counterbalancing force that compensates for the insufficient potential energy from the trunk weight alone.
Solution Approach 2:
The patent employs a ratchet mechanism that allows periodic, unidirectional movement of the seat assembly. The ratchet mechanism permits the seat to move upward in discrete steps while preventing backward movement, enabling the system to accumulate lifting action over multiple cycles. This periodic action allows the power apparatus to build up lifting capability through repeated energy storage and release cycles in the counterweight spring.
2Ease of operation
If first type of lift apparatus tilts seat forward to raise user, then standing up is facilitated, but frail patients may slide down the tilted seat onto the ground
Solution Approach 1:
The patent employs a second type of lift apparatus that maintains the seat in a substantially horizontal position throughout the lifting and lowering operations. This dynamic positioning system uses parallel stanchions and pivot mechanisms to keep the seat surface level, preventing users from sliding forward or backward. The horizontal seat position is maintained while the seat assembly moves vertically, providing both safety during descent and ease of operation during ascent.
3Power
If external energy sources like electric motors are used to elevate user, then lifting assistance is provided, but the devices become bulky, heavy, and expensive
Solution Approach 1:
The patent implements a self-service energy system where the counterweight spring is automatically charged during the user's downward movement and automatically discharged during the upward movement. The user's own body weight and movement provide the energy source, eliminating the need for external power sources like electric motors. The ratchet mechanism ensures this self-service operation occurs in the correct direction without requiring complex control systems or heavy power supplies.
Solution Approach 2:
The patent replaces electric motor-driven mechanical systems with a passive mechanical energy storage and release system. Instead of using electric motors, batteries, and electronic controls, the invention uses spring-based potential energy storage, leverages, and ratchet mechanisms - all purely mechanical components that are significantly lighter and simpler than their electric counterparts.
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 device effectively reduces torque exerted by the trunk weight, allowing users to stand up safely and efficiently without bulky external energy sources, providing a cost-effective and portable solution.
Implementation Method 1
a power apparatus under the stationary seat, the power apparatus comprising at least two wrap springs and a gas spring, the power apparatus configured to release potential energy saved from a seated user to lift the seated user towards a standing position
Implementation Method 2
the at least two sets of stanchions, the stationary seat, and the base together form a 3D quadrilateral structure. In some examples, pivoting the lift apparatus expands and contracts the 3D quadrilateral structure, thereby raising and lowering the stationary seat
Data Source
AI summary
Apparatuses and techniques for assisting physically impaired persons to sit and stand are disclosed herein. A sit-to-stand apparatus may include a base having a front base bracket, a rear base bracket, and side base brackets, a slidable seat apparatus positioned above the base configured to slide forward and backward, a lift apparatus, and a power apparatus under the stationary seat, the power apparatus comprising at least two wrap springs and a gas spring, the power apparatus configured to release potential energy saved from a seated user to lift the seated user towards a standing position. The front base bracket, the rear base bracket, and the two side base brackets together form a rectangular structure. The base may be coupled to a chair, a bench, a wheelchair, a toilet seat, a commode, and other seat types.