Folding Lock Hinge Geometry to Eliminate Pinch Points
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Solution Overview
Problem
Collapsible frames for infant enclosures, such as cribs and play yards, often create pinch points when folded due to congested frame members, posing a hazard to users.
Innovation Solution
A folding lock mechanism with two hinges, one allowing angular rotation less than 90 degrees and the other greater than 90 degrees, offsetting frame members to eliminate pinch points while enabling easy folding and unfolding, and a latching mechanism for secure locking and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If frame members are moved into adjacent contact to minimize collapsed space, then the volume of the collapsed frame is reduced, but pinch points are created between frame members
Solution Approach 1:
The patent introduces a third dimension by offsetting frame members laterally perpendicular to the folding plane. The L-shaped configuration and lateral offset create spatial separation between frame members that would otherwise contact during folding, eliminating pinch points while maintaining compact collapsed volume.
Solution Approach 2:
The patent nests the lateral offset mechanism within the overall folding structure. The offset arms are integrated into the frame members themselves, allowing the compact nested configuration during collapse while maintaining the safety offset when folded.
2Object-affected harmful factors
If different length frame portions are used to offset distal ends during folding, then pinch points are eliminated, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces controlled asymmetry through the L-shaped configuration and lateral offset, which creates the necessary geometric relationship to eliminate pinch points while maintaining symmetry in the overall frame structure for manufacturing efficiency.
Solution Approach 2:
The patent changes the geometric parameters of the frame members by introducing lateral offsets and angular relationships (non-180 degree fold angles). This allows equal-length members to achieve the pinch-point elimination effect that traditionally required different lengths.
3Ease of operation
If hinge rotation range is increased to allow full folding, then ease of operation is improved, but pinch points are created between frame members
Solution Approach 1:
The patent makes the hinge rotation range dynamic and selective - allowing full rotation for folding operations while the lateral offset geometry automatically prevents pinch points during the folded configuration. The system adapts its effective rotation range based on the operational phase.
Solution Approach 2:
The lateral offset acts as an intermediary geometric feature that mediates between the need for full folding range and the need to eliminate pinch points. It allows the frame members to pass through the folding motion while maintaining safe separation at the critical contact points.
Data Source
AI summary
A folding lock assembly for use in a frame for a portable child enclosure that includes a body housing first and second hinges for connecting a pair of equal-length side frame members. The respective hinges are limited in the degree of pivotal movement permitted each between a locked position in which the frame members are linearly aligned and a folded position in which the frame members are substantially parallel. The first hinge permits angular rotation less than 90 degrees while the second hinge permits angular rotation greater than 90 degrees. The differences in the range of hinge rotation offset the distal ends of the frame when the connected members are folded to eliminate a pinch point between frame end members. A latching mechanism is provided to maintain the hinges in a locked configuration wherein one hinge is locked by the position of the second hinge. Releasing the second hinge allows the first hinge to pivot as well.