Foldable Trestle Leg Locking for Compact Stable Folding
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Solution Overview
Problem
Existing collapsible trestles face challenges with high manufacturing costs due to the need for legs of different lengths and compromised compactness, which affects stability and support surface area when folded.
Innovation Solution
The trestle design incorporates blocking means, such as compasses and a stirrup, to immobilize legs in the unfolded position, ensuring stability and compactness by aligning feet transversely when folded, eliminating the need for protruding hinge devices and allowing for a larger support surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If legs of different lengths are used to accommodate non-uniform attachment positions, then the trestle can be folded compactly, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by positioning articulation means at different locations along the crosspiece (first articulation means at one end, second articulation means at the other end), allowing each leg pair to be attached at optimal positions while maintaining uniform leg lengths. This resolves the contradiction by enabling compact folding through strategic placement rather than dimensional variation.
2Volume of moving object
If legs are positioned one on top of the other inside the crosspiece, then transverse compactness is improved, but the support surface area is reduced
Solution Approach 1:
The patent resolves this contradiction by changing the folding dimension from transverse (side-by-side) to longitudinal (one on top of the other). The legs fold along the length of the crosspiece rather than across its width, achieving compactness in the transverse dimension while preserving the full support surface area in the longitudinal dimension.
3Stability of the object's composition
If divergent wings are used in articulation devices to ensure stability, then stability is improved, but the folded position becomes bulky and protruding
Solution Approach 1:
The patent extracts the stabilizing function from the protruding wings and relocates it to blocking means positioned inside the crosspiece. The blocking means prevent leg collapse without requiring external protrusions, thereby maintaining stability while achieving a compact folded profile.
4Ease of operation
If a specific folding sequence is required (first pair then second pair), then the trestle can be folded, but operation complexity increases
Solution Approach 1:
The patent applies segmentation by providing independent articulation means for each leg pair, with each articulation device equipped with its own blocking means. This independence allows each leg pair to be folded autonomously without requiring a specific sequence, simplifying the folding operation.
Data Source
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AI summary
The invention concerns a foldable trestle (10) having a folded position and a deployed position, said trestle comprising a cross-member (12) having longitudinal (L) and transverse (I) dimensions defining a lower surface (F), first and second pairs of legs (14, 16), hinge means enabling the legs (14a,14b,16a,16b) of each of the pairs of legs to be mutually spaced apart when the trestle (10) is in deployed position, and to extend against one another when the trestle is in folded position, the hinge means (18, 20) enabling further each of the pairs of legs to de pivoted about an axis transverse to the cross-member such that in folded position, the pairs of legs (14, 16) extend beneath said lower face of the cross-member. The invention is characterized in that the trestle further comprises first locking means (22, 24) linking one side (140b) of one of the legs (14b, 16a) of at least one of the pairs of legs (14, 16) to the cross-member (12) so as to lock in deployed position said pair of legs relative to the cross-member.