Telescopic column for a height-adjustable table and height-adjustable table having such a telescopic column
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Solution Overview
Problem
Telescopic columns with a circular cross-section for height-adjustable tables face challenges in achieving low displacement forces for height adjustment due to the limitations of using roller guides, which cause issues with radial alignment and backlash-free operation.
Innovation Solution
A telescopic column design featuring a cylindrical outer and inner column with a ball cage system, where the columns have specific surface properties and grooves to allow balls to roll smoothly and backlash-free, along with a guiding ring for alignment and stability, enabling low displacement forces during height adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If roller guides are used in telescopic columns with circular cross-section, then displacement force is reduced, but radial alignment and backlash-free operation deteriorate
Solution Approach 1:
The running surface is segmented into multiple sections (first, second, third, and fourth running surface sections) with different orientations. These segmented surfaces guide the balls in specific directions to achieve both low friction and precise alignment, resolving the contradiction between reducing displacement force and maintaining radial alignment.
Solution Approach 2:
Different regions of the running surface are given different qualities and orientations. The first and second running surface sections have different orientations from the third and fourth sections, creating local variations that optimize both friction reduction and alignment characteristics in different areas of the telescopic column.
2Reliability
If sliding guides are used in telescopic columns with circular cross-section, then radial alignment is maintained, but displacement force increases
Solution Approach 1:
The telescopic column uses a circular cross-section with spherical balls instead of rectangular designs. The curved running surfaces are specifically oriented to guide these spherical elements, combining the advantages of circular geometry (aesthetic and structural) with low-friction rolling motion, thereby reducing displacement force while maintaining alignment.
Solution Approach 2:
The system transitions from static sliding contact to dynamic rolling contact by incorporating balls that move along curved running surfaces. This dynamic approach allows the balls to roll rather than slide, significantly reducing friction and displacement force while the oriented surfaces maintain radial alignment through controlled motion paths.
3Manufacturing precision
If the running surface sections are oriented at different angles, then ball guidance and alignment improve, but manufacturing complexity increases
Solution Approach 1:
The running surface sections are deliberately oriented asymmetrically at different angles (e.g., 45 degrees, 135 degrees) rather than symmetrically. This asymmetric orientation provides superior ball guidance and alignment precision, while the modular design of these asymmetric sections makes them manufacturable using standard machining processes.
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 design allows for low displacement forces during height adjustment, ensuring convenient operation and maintaining a backlash-free alignment of the tabletop, while the cylindrical shape and ball cage system retain the balls in predetermined positions for smooth motion.
Implementation Method 1
the balls roll over thereon... the balls roll over almost backlash-free in order to guide the inner column in the outer column
Implementation Method 2
roller guides are employed instead of also usual sliding guides. Thereby, a friction value can reduced about a factor 10
Data Source
AI summary
A telescopic column for a height-adjustable table comprises a cylindrical outer column, a cylindrical inner column at least partially arranged within the outer column, several balls, and a tube-shaped ball cage retaining the balls at positions relatively determined with respect to one another. The outer column comprises, along its longitudinal direction on its inside, an outer column running surface section configured such that the balls roll over thereon, the inner column comprises, along its longitudinal direction on its outer cross-section, an inner column running surface section configured such that the balls roll over thereon, and the inner column and the outer column are configured such that the balls, during an adjustment of a length of the telescopic column, roll over in an almost backlash-free manner on the outer column running surface section and the inner column running surface section in a predefined range of motion of the balls in order to guide the inner column in the outer column.