Frame for a sit-stand-table
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Solution Overview
Problem
Existing frames for height-adjustable tables are cumbersome to assemble due to large and heavy parts requiring multiple screw operations, and suffer from unreliable connections prone to manufacturing tolerances leading to instability and scratching of surfaces.
Innovation Solution
A self-tightening fastening mechanism using bolts and activation pins that automatically adjust for manufacturing tolerances, ensuring a secure and intuitive assembly and disassembly of lifting columns and feet without surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional screw assembly methods are used to connect lifting columns and feet, then the connection can be secure, but the assembly process becomes time-consuming and complex requiring multiple screw operations
Solution Approach 1:
The connection system is segmented into distinct functional elements: connection elements with threading, fastening elements with corresponding threads, and guide elements. This segmentation allows for a simplified assembly process where parts are designed to connect through straightforward insertion and tightening motions rather than multiple screw operations, reducing assembly time while maintaining secure connection through the threaded engagement mechanism
Solution Approach 2:
The connection system incorporates self-aligning features where the guide elements automatically position the connection elements and fastening elements relative to each other during assembly. The threading geometry itself guides the fastening element onto the connection element, eliminating the need for precise manual alignment and multiple adjustment operations, thus reducing assembly time without compromising connection reliability
2Strength
If multiple screw operations are required for assembly, then secure fastening can be achieved, but the assembly process becomes difficult and requires precise positioning of parts
Solution Approach 1:
Guide elements act as intermediaries between the connection elements and fastening elements. These guide elements provide physical constraints and alignment features that automatically position the threaded connection elements and fastening elements correctly relative to each other. This intermediary structure eliminates the need for operators to manually position parts with high precision, significantly easing assembly operations while ensuring that the threaded fastening achieves proper engagement and sufficient fastening strength
Solution Approach 2:
The connection system is designed so that the threading geometry and guide element positioning create an equipotential assembly state where the natural tendency of the parts to engage their threaded interfaces aligns with the correct final position. This design eliminates the need for multiple incremental screw operations and precise step-by-step positioning, allowing assembly to proceed through a single continuous motion that naturally achieves the correct alignment and secure fastening
3Reliability
If locking mechanisms with turning motion are used to secure feet, then the connection can be reliable, but the surface of the foot gets scratched
Solution Approach 1:
The harmful turning motion that causes surface scratching is extracted and separated from the fastening function. Instead of using a turning motion to engage locking features, the design uses linear insertion of threaded fastening elements into threaded connection elements. The scratching action is completely removed from the assembly process, eliminating surface damage while maintaining reliable connection through the threaded engagement mechanism
Solution Approach 2:
The mechanical turning and locking mechanism is substituted with a threaded fastening system. Rather than rotating a foot or component to engage locking lugs or tracks, the system uses screw-threaded connection elements that are inserted and tightened in a linear motion. This substitution eliminates the rotational friction and surface contact that cause scratching, while achieving equally reliable or superior connection reliability through the threaded engagement
4Ease of manufacture
If locking tracks with inclination are used to assemble foot and lifting column, then connection can be achieved, but manufacturing tolerances cause unreliable assembly and potential deformation
Solution Approach 1:
The connection system uses standardized threading parameters (thread pitch, diameter, and profile) that provide self-aligning and self-correcting characteristics. The threaded geometry inherently compensates for small dimensional variations in the connection elements and fastening elements, allowing assembly to succeed despite manufacturing tolerances. This parameter-based approach replaces the inclination-based locking track system that is highly sensitive to tolerance accumulation, achieving both ease of manufacture and tolerance robustness
Data Source
Figure 1~3
Figure 4~5
Figure 6~7b
AI summary
The present invention relates to a frame for a sit-stand-table having a fastening mechanism for assembling a height-adjustable lifting column with a foot. The lifting columns comprises at least two telescopically arranged profiles. Two bolts and two activation pins are attached to the lower end of a profile of the lifting column. The fastening mechanism is arranged inside the foot and configured to engage with the bolts and activation pins through holes in an upper part of the foot. When activated by the activation pins, the fastening mechanism engages the bolts and pulls the lower end of the profile into a forced engagement with the upper side of the foot. This forced engagement is so tight that the lifting column is immovably assembled with the foot.