Telescopic Lifting Column Rack Guide to Prevent Wedging
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Solution Overview
Problem
Existing telescopic lifting columns require large cross-sectional dimensions for bending stability, leading to high production costs and increased friction, which results in a wedging effect and high motor power requirements due to tight tolerances and surface irregularities.
Innovation Solution
The telescopic lifting column design incorporates a toothed rack with a narrow guide way and guide pins, combined with plastics sliders for secondary loads, optimizing bending stability and reducing friction, allowing for thinner profiles and lower production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large cross-sectional dimensions are used for telescopic profiles, then bending stability is improved, but production costs and friction increase
Solution Approach 1:
The lifting column is divided into a stationary profile and a sliding profile that move relative to each other. The toothed rack is integrated into the sliding profile, separating the lifting function from the guide function. This segmentation allows each component to be optimized independently, reducing the need for large cross-sectional dimensions while maintaining bending stability.
Solution Approach 2:
Guide pins are introduced as intermediary elements that engage with the guide way in the stationary profile. These guide pins provide linear guidance and support, transferring loads efficiently between the sliding and stationary profiles. This intermediary mechanism enables the use of thinner profiles while maintaining stability, as the guide pins bear the guidance and support loads.
2Manufacturing precision
If tight tolerances are required for accurate sliding, then manufacturing precision is improved, but production costs and friction increase
Solution Approach 1:
The guide pins act as intermediaries between the sliding profile and stationary profile, providing a mechanical reference for linear motion. The guide way in the stationary profile and the guide pins work together to define the sliding path, allowing for adequate tolerances while maintaining accurate linear guidance. This eliminates the need for tight tolerances on the sliding surfaces themselves.
3Force
If the sliding profile is in maximum lifting position, then lifting capacity is maximized, but friction and wedging effect increase due to surface irregularities
Solution Approach 1:
Guide pins are introduced as intermediary elements that engage with the guide way in the stationary profile. These guide pins provide linear guidance and support, transferring loads efficiently between the sliding and stationary profiles. This intermediary mechanism reduces direct contact friction between the profiles and eliminates the wedging effect by providing a controlled guidance path.
Solution Approach 2:
The direct sliding contact between the sliding profile and stationary profile is replaced by a gear mechanism (toothed rack and pinion) for power transmission, while the guide pins provide frictionless linear guidance. This substitution separates the power transmission function from the guidance function, reducing friction and eliminating the wedging effect that occurs with direct mechanical sliding contact.
Data Source
AI summary
A telescopic lifting column for height adjustment of elevatable tables (1) consists of a stationary rectangular profile (2), which at the bottom rests against a floor, and of a sliding quadrangular profile (3), which slides inside the stationary profile (2) and which can be activated up or down by a linear actuator (4) and which at the top rests against a table top (7). The profiles (2, 3) each have an open side (resp. 8 and 9), and the linear actuator is embodied as a toothed rack (10), which is fastened to the internal side (3′) of the sliding profile (3) opposite the open side (9), and which is in mesh with a toothed wheel (11), which is coupled to a gear motor (12,13), which is fastened to the stationary profile (2) of the lifting column. On the side facing the open side (9), the toothed rack (10) is embodied with a guide way (18) with a width (a) in which two guide pins (19, 20)—with a mutual distance (b) and fastened to the stationary profile (2)—are in mesh.