Tension-Spring Scissor Lifting Platform for Constant Support Force
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Solution Overview
Problem
Existing lifting devices face challenges in providing a constant and linear supporting force over the lifting height, often requiring complex spring mountings and maintenance, and are unsuitable for mobile applications due to high moving masses.
Innovation Solution
A load-compensating device combining mechanically acting spring elements with a scissor mechanism, utilizing a spreading unit and scissors arrangement to achieve a substantially constant lifting force, with adjustable geometry for linearity and constancy, and incorporating tension springs for compact and low-maintenance operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If compression spring elements are directly attached between bottom frame and top frame to achieve load relief, then the load on lifting mechanism and drivetrain is reduced, but massive guide elements and complex spring mountings are required to prevent buckling
Solution Approach 1:
A tension spring element is introduced as an intermediary component between the lifting mechanism and the platform. This tension spring acts as a mediator that provides load relief through its prestress force without requiring complex compression spring mountings or massive guide elements to prevent buckling, as tension springs inherently maintain structural stability
Solution Approach 2:
Instead of using compression springs that require complex mounting structures to prevent buckling, the invention inverts the approach by using tension springs. The tension spring element is arranged to be pulled rather than compressed, eliminating the need for massive guide elements and complex spring mountings while still achieving load relief
2Power
If high spring prestress is applied to achieve significant load relief in upper position, then load relief is improved, but complex maintenance concepts are required to reliably separate spring energy
Solution Approach 1:
The tension spring element is designed to automatically form a block in the upper lifting position through its own prestress force. This self-blocking mechanism eliminates the need for complex maintenance concepts or additional devices to isolate spring energy, as the spring's own tension creates a natural mechanical lock that safely contains the stored energy during maintenance operations
Solution Approach 2:
The invention changes the spring characteristic from compression to tension, which fundamentally alters how the spring energy is stored and released. This parameter change allows the spring to naturally form a blocked state in the upper position through its prestress, simplifying maintenance procedures while maintaining effective load relief
3Power
If spring elements are directly incorporated, then load relief is achieved, but it is impossible to produce a constant force profile over the entire stroke since spring force increases during contraction
Solution Approach 1:
The invention inverts the spring action from compression to tension. This inversion allows the spring to be arranged in series with the lifting mechanism, where it can provide a substantially constant force profile throughout the lifting stroke. The tension spring's force characteristics can be better controlled and maintained constant compared to compression springs that naturally increase force during contraction
4Force
If compensating weights are used to provide constant support over lifting height, then constant supporting force is achieved, but high moving masses make them unsuitable for mobile applications
Solution Approach 1:
The invention replaces the mechanical compensating weight system with a tension spring element that provides load relief through elastic prestress. This substitution eliminates the high moving masses associated with compensating weights while still achieving substantially constant supporting force over the lifting height, making the system suitable for mobile applications
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 nearly constant lifting force with minimal deviation, reduces manufacturing and maintenance efforts, and is suitable for both new and existing lifting systems, enhancing power density and efficiency while reducing drive power and energy consumption.
Implementation Method 1
The spring element is configured as at least two tension springs acting in parallel and is prestressed with a spring prestress
Implementation Method 2
transfers a spring force of the spring element into a scissors arrangement, where, by virtue of the scissors arrangement, the spring force acts as a resultant lifting force
Data Source
AI summary
A load-compensating device for a lifting application with an object to be lifted or lowered includes a movable platform, wherein the platform carries the object and, for purposes of load compensation, the platform is supported by at least one spring element that acts on a spreading unit which, in order to achieve spreading, transfers a spring force of the spring element into a scissors arrangement, where, by virtue of the scissors arrangement, the spring force results in a lifting force that produces a lifting action on the platform, and where a substantially constant lifting force is provided over a substantial lifting distance of the platform by the lifting geometry formed via the spreading unit and the scissors arrangement.