Bath Tub Lifter Scissor Joint for Simpler Reliable Assembly
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Solution Overview
Problem
Existing bath tub lifters are labor-intensive and cost-intensive due to complex coupling mechanisms of scissor legs, which complicates assembly and increases production costs while compromising reliability.
Innovation Solution
A bath tub lifter design featuring a scissor lift arrangement with radially joined scissor elements that prevent separation through form closure, eliminating the need for additional locking elements and allowing for a lighter, more rigid structure with reduced parts, enabling economical production and enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional coupling mechanisms with multiple locking elements are used to join scissor legs, then connection reliability is improved, but device complexity and assembly labor increase
Solution Approach 1:
The patent combines the bearing function and locking function into a single integrated bearing element. The bearing simultaneously provides rotational support and form-closure locking through its geometric design, eliminating the need for separate locking elements like circlips or locking pins. This merging reduces the number of parts and simplifies assembly while maintaining connection reliability.
Solution Approach 2:
The bearing is designed to automatically lock scissor elements in place through form closure based on geometric constraints. The bearing's shape and the scissor elements' configuration create self-locking conditions that prevent radial separation without requiring active locking mechanisms. The system locks itself through its own geometric properties during operation.
2Reliability
If additional locking elements are used to prevent radial separation of scissor elements, then operating reliability is improved, but weight and device complexity increase
Solution Approach 1:
The locking function is merged into the bearing structure itself through geometric design. The bearing and scissor elements are shaped to create form-closure conditions that prevent radial separation. This eliminates the need for additional locking elements like circlips or locking pins, reducing overall weight while maintaining operating reliability throughout the lifting range.
3Ease of manufacture
If axial assembly method is used to join scissor elements, then assembly is simplified, but scissor element rigidity is compromised due to bending requirements
Solution Approach 1:
The patent transitions from axial assembly (along the bearing axis) to radial assembly (perpendicular to the bearing axis). By assembling the bearing and scissor elements in the radial direction, the scissor elements can be directly connected without bending, preserving their full rigidity. The form-closure design ensures that once radially assembled, the elements remain securely locked throughout operation.
Data Source
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AI summary
A bath tub lifter, comprising a seat element (1 ), a lifting apparatus (4) for raising and lowering the seat element (1 ) between a lower operating end position and an upper operating end position, and a scissor lift arrangement (10) having two pairs of scissor lifts with scissor elements, wherein, in the operative state, respectively two scissor elements are coupled to each other such that they are mutually pivotable about a bearing axis.