Sit assist device
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Solution Overview
Problem
Existing sit assist devices face challenges in providing consistent support due to varying user weights and the weak force provided by spring damper cylinders at shallow angles, and powered devices are heavy, complex, and prone to breakdown.
Innovation Solution
A sit assist device with a primary biasing means, such as a spring damper, and a secondary biasing means, like a coil or leaf spring, to provide resilient support over the operating range, ensuring consistent assistance for users of different weights and addressing the weakness of spring damper cylinders at shallow angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a spring damper cylinder is used to provide resilient bias, then the device can assist users to sit down and stand up, but the force provided becomes weak when the sitting platform is near the lowered position due to shallow operating angles
Solution Approach 1:
The resilient biasing system is segmented into two separate components: a primary spring damper cylinder and a secondary spring. Each component operates effectively in different portions of the operating range, with the primary handling the majority of the range and the secondary providing supplemental force when the primary becomes ineffective near the lowered position.
Solution Approach 2:
The secondary spring is specifically designed to provide supplemental resilient bias only in the portion of the operating range adjacent to the lowered position where the primary spring damper cylinder's force becomes weak. This localized enhancement ensures consistent support throughout the entire range of motion without requiring the primary component to be oversized.
2Force
If the resilient bias is designed to provide suitable support for heavy users, then heavy users receive adequate assistance, but light users experience excessive force that prevents the sitting platform from moving from raised to lowered position
Solution Approach 1:
The resilient biasing function is divided between two components with different force characteristics. The primary spring damper cylinder is designed with a force profile suitable for heavy users, while the secondary spring provides additional force only when needed for lighter users, enabling the system to adapt to a wider range of user weights.
Solution Approach 2:
The system dynamically adjusts the total resilient bias force based on the sitting platform's position. The secondary spring engages only when the platform is near the lowered position, providing variable support that adapts to different user weights without requiring manual adjustment or complex control mechanisms.
3Adaptability or versatility
If powered devices with electric motors are used to move the sitting platform, then consistent support can be provided for all users, but the devices become heavy, complex, and prone to breakdown
Solution Approach 1:
The dual spring system is entirely passive and self-regulating. The springs automatically provide the appropriate resilient bias force based on the sitting platform's position and the user's weight, without requiring external power sources, control systems, or active components. This mechanical self-service approach eliminates the complexity and reliability issues associated with powered devices.
Solution Approach 2:
The patent replaces complex powered mechanical systems (electric motors, gearings, hydraulic or pneumatic cylinders) with a simpler passive mechanical system using two springs. This substitution maintains the ability to provide consistent support for all users while dramatically reducing device complexity, weight, and maintenance requirements.
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 dual biasing system ensures consistent and effective support for users, enhancing the usability and portability of the device by providing adequate force throughout the range of motion, while avoiding the drawbacks of powered devices.
Implementation Method 1
a primary biasing means providing a primary resilient bias to resiliently bias the sitting platform from the lowered position to the raised position
Implementation Method 2
a secondary biasing means providing a secondary resilient bias to supplement the primary resilient bias over a portion of the operating range adjacent the lowered position
Data Source
AI summary
A sit assist device (1) comprising a base (2) adapted to be supported by a seating surface, and a sitting platform (3) hingedly connected to the base (2) and movable between a raised position and a lowered position to assist a user to sit down onto and to stand up from the sitting platform (3). A primary biasing means (4) provides a primary resilient bias to resiliently bias the sitting platform (3) from the lowered position to the raised position over an operating range, thereby moving the sitting platform (3) from the lowered position to the raised position over the operating range as the user stands up from the sitting platform (3) and slowing the movement of the sitting platform (3) from the raised position to the lowered position over the operating range as the user sits down onto the sitting platform (3). A secondary biasing means (5) provides a secondary resilient bias to supplement the primary resilient bias over a portion of the operating range adjacent the lowered position.