Zero Play Stroller Hinge Axial Locking Mechanism
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Solution Overview
Problem
Conventional stroller hinges exhibit play in the locked state, leading to instability and reduced consumer satisfaction due to gaps between components, which affect the perception of quality.
Innovation Solution
A stroller hinge design featuring a first and second housing portion, a release actuator, and a locking member with an incline surface that engages both housing portions in the locked state, allowing for zero or near-zero play by using a frustoconical locking member that moves axially between locked and unlocked states, ensuring a rigid joint without visible gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gaps are provided between hinge components to enable easy operation and proper seating, then the hinge can be easily operated between locked and unlocked states, but play is introduced in the locked state reducing stability
Solution Approach 1:
The hinge is divided into multiple functional components: a locking member with cam surfaces, a retainer with locking surfaces, and a spring mechanism. This segmentation allows each component to perform its specific function - the cam surfaces enable easy actuation, the locking surfaces provide rigid engagement, and the spring maintains proper tension, collectively resolving the contradiction between ease of operation and stability.
Solution Approach 2:
The locking member acts as an intermediary element between the first and second frame members. Its cam surfaces engage with corresponding surfaces on the frame members to provide the locking action, while its interaction with the retainer ensures rigid positioning. This intermediary mechanism enables easy operation through cam engagement while maintaining stability through the retainer locking system.
2Ease of manufacture
If gaps are provided between hinge components, then the hinge components can properly seat to transition to the locked state, but visible gaps reduce consumer perception of quality
Solution Approach 1:
The hinge transition from unlocked to locked state is designed as a dynamic process. During actuation, gaps between components allow smooth movement and proper seating of the locking surfaces. Once locked, the cam surfaces and locking surfaces engage to eliminate visible gaps, providing both ease of assembly and high perceived precision.
Solution Approach 2:
The spacing between hinge components is designed to change based on the operational state. In the unlocked state, larger gaps allow for easy component seating and assembly. In the locked state, the cam and locking surfaces engage to reduce the effective gap to near-zero, providing both manufacturing ease and precision appearance.
3Stability of the object's composition
If a tighter fitting hinge is used to eliminate play, then consumer satisfaction and perception of quality increase, but the hinge becomes more difficult to operate
Solution Approach 1:
The locking member incorporates cam surfaces with specific curvature profiles. These curved surfaces provide a mechanical advantage during actuation, allowing the locking member to be easily pushed from the locked to unlocked state. The curvature enables smooth transition while maintaining rigid engagement when locked, resolving the contradiction between ease of operation and hinge rigidity.
Solution Approach 2:
The spring mechanism is pre-loaded to maintain constant tension on the locking member. This preliminary action ensures that the locking surfaces are always under light pressure, ready for easy actuation. When the cam surface is pushed, the pre-loaded spring immediately responds, facilitating easy operation while maintaining the rigid locked position through the pre-tensioned engagement.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A hinge for pivotally joining a first frame member and a second frame member of a frame of a stroller may include a first housing portion (110), a second housing portion (120), a release actuator (140) and a locking member (130). The first housing portion may be operably coupled to the first frame member. The second housing portion may be operably coupled to the second frame member. The release actuator may be configured to operate to enable the hinge to shift between a locked state and an unlocked state. The locking member may be configured to move in an axial direction responsive to shifting between the locked state and the unlocked state. The external periphery of the locking member may include a first incline surface () that engages both the first housing portion and the second housing portion in the locked state.