Connecting Fitting Cam-Driven Expandable Members Furniture
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Solution Overview
Problem
Conventional connecting fittings for furniture suffer from reduced retaining effectiveness due to marks left on the inner surfaces of holes after repeated use, as the expansion mechanism wears out and loses grip over time.
Innovation Solution
A connecting fitting with a cam surface-driven inserting assembly, comprising expandable members with snap portions that expand to securely engage with the inner surface of holes, allowing for quick assembly and disassembly by pivoting the body, which maintains secure connections without leaving permanent marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the expansion member expands the dowel to secure it in the hole, then the connecting fitting achieves strong retention, but the teeth leave marks on the inner surface of the hole after repeated use
Solution Approach 1:
The inserting member is divided into a head portion and a body portion, with the body portion being pivotally connected to the body. This segmentation allows the head portion to be the element that contacts and expands against the hole surface, while the body portion can pivot independently, distributing the mechanical stress and reducing concentrated wear marks on the furniture surface.
Solution Approach 2:
The inserting assembly is designed to pivot about a shaft, transforming the static expansion mechanism into a dynamic one. When the body is pivoted, the inserting assembly rotates, causing the expandable members to sequentially engage and disengage from the hole surface. This dynamic motion prevents the teeth from constantly pressing against the same spot, thereby reducing mark formation while maintaining retention strength.
2Reliability
If the holding member is turned to expand the dowel for secure connection, then the connecting fitting achieves reliable retention, but the expansion mechanism wears out and loses grip over time
Solution Approach 1:
The pivotable inserting assembly creates a dynamic engagement mechanism where the expandable members are pushed against the head portion during pivoting motion. This dynamic action distributes wear across multiple contact points and cycles, preventing concentrated wear at a single location, thereby extending the service life while maintaining reliable retention.
Solution Approach 2:
The head portion acts as an intermediary element between the expandable members and the hole surface. The expandable members expand against the head portion rather than directly against the furniture, and the head portion transmits this force to secure the connection. This intermediary protects the expandable members from direct wear contact with the furniture surface, extending their service life.
3Ease of operation
If the cam surface drives the expandable members to expand the snap portions, then quick assembly is achieved, but the mechanism requires precise coordination of multiple components
Solution Approach 1:
The cam surface, expandable members, and inserting assembly are merged into an integrated mechanism where the cam surface directly actuates the expandable members through the pivot motion. This merging eliminates the need for separate actuation mechanisms, reducing overall complexity while maintaining quick assembly capability. The single pivoting motion simultaneously achieves both the expansion and the securing actions.
Solution Approach 2:
The cam surface is designed to automatically drive the expandable members to expand the snap portions against the head portion during the natural pivoting motion of assembly. The mechanism uses its own motion to activate the expansion, eliminating the need for external actuators or complex control systems, thereby achieving quick assembly without excessive complexity.
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 solution ensures reliable and repeatable secure connections without damaging the furniture surfaces, as the expandable members can be reused multiple times, maintaining the integrity of the connection without wear and tear, thus extending the lifespan of the fitting.
Implementation Method 1
the expandable portion being urged by a push force from the cam surface of the body and the plug to hold against the head portion of the inserting member
Implementation Method 2
the expandable portion comprising a plurality of notches and snap portions; and the plug fitted on the body portion of the inserting member and located between the expandable members and the body, the expandable portion being urged by a push force from the cam surface of the body and the plug to hold against the head portion of the inserting member and to expand the snap portions outwardly
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A connecting fitting (10) includes a body (12) having a cam surface (32) and an inserting assembly (14) which is pivotally connected with the body (12). The inserting assembly (14) includes an inserting member (16) and at least one expandable member (18) mounted between the body (12) and the inserting member (16). The expandable member (18) includes an expandable portion (44) and a lip portion (46) extending from the expandable portion (44). A compressible space (48) is defined by the expandable portion (44) and the lip portion (46), and the expandable portion (44) has a plurality of snap portions (52). When the body (12) is axially turned relative to the inserting assembly (14) at a certain angle to generate a push force, the snap portions (52) will be expanded outwardly by the push force.