Backrest, lumbar support, chair, attachment structure for optional member, optional member, and furniture
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Solution Overview
Problem
Conventional chair designs face challenges in easily attaching and securely maintaining optional members like lumbar supports due to complex operations and potential rattling or separation issues caused by load moments, especially when the shapes of attachment portions and members do not fit perfectly.
Innovation Solution
A backrest design featuring a tensile material with a load support surface, a frame member with an attachment portion that intersects the load support surface, and an optional member with an attaching portion that inserts into a gap between the tensile material and the attachment portion, ensuring easy attachment and robust fixation, while also accommodating shape differences and preventing separation from load-induced moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the attachment portion is formed by surface contact with the frame member, then the optional member can be strongly attached, but the attachment operation becomes complicated and time-consuming
Solution Approach 1:
The attachment structure is divided into two distinct components: a protrusion portion extending from the frame member and an insertion portion on the optional member. This segmentation allows for simple insertion without complex surface contact operations, significantly reducing attachment time while maintaining reliability through the interlocking geometry of the protrusion and insertion portions.
Solution Approach 2:
The insertion portion of the optional member is inserted into and nested within the protrusion portion of the frame member. This nesting configuration creates a secure fit that maintains attachment strength while enabling straightforward attachment and detachment operations, eliminating the need for complex surface contact procedures.
2Ease of operation
If the optional member is attached using conventional attachment portions, then attachment is possible, but the optional member may rattle or separate due to load-induced moments
Solution Approach 1:
The protrusion portion is pre-formed on the frame member with dimensions and geometry designed to accommodate the insertion portion. This preliminary preparation ensures that when the optional member is attached, the insertion portion fits securely into the protrusion portion, preventing rattling and separation under load-induced moments without requiring complex attachment procedures.
3Adaptability or versatility
If the attachment portion is designed to accommodate shape differences, then adaptability is improved, but the attachment strength may be compromised
Solution Approach 1:
The protrusion portion and insertion portion are designed with adjustable dimensional parameters that can accommodate variations in shape while maintaining secure attachment. By optimizing the geometry and dimensions of these components, the structure achieves both adaptability to different optional members and sufficient attachment strength to prevent separation under load.
Data Source
AI summary
A backrest (7) includes: a tensile material (71) on which a load support surface (71f) configured to receive a load of a seated person is formed; a back front frame (80F) that supports an outer peripheral end portion (71e) of the tensile material (71); an attachment portion (87) which is formed in the back front frame (80F) and faces the tensile material (71) in a state where the attachment portion (87) is separated from the tensile material (71) in a direction intersecting the load support surface (71f); and a lumber support (200) that is attachable to and detachable from the attachment portion (87), in which the lumber support (200) includes an attaching portion (222) which extends in a direction along the load support surface (71f), is inserted into a gap (S) between the tensile material (71) and the attachment portion (87), and is fixed to the attachment portion (87).