Bleacher deck interlock apparatus and method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing retractable bleacher systems experience undesirable vertical movement and noise due to operating clearances, leading to a bouncy feeling and excessive friction, which are not consistently maintained across varying deck weights and sizes.
Innovation Solution
A deck interlock apparatus comprising a pawl and a capture bracket that securely maintain a designed vertical clearance between adjacent tiers when fully extended, preventing vertical movement and eliminating noise by engaging only upon full extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If operating clearance is designed into the bleacher system to allow tiers to slide past each other, then the bleacher can be extended and retracted smoothly, but vertical deck motion and noise occur when fully extended
Solution Approach 1:
The system dynamically changes the state of the interlock mechanism based on the bleacher position. During extension/retraction, the pawl is disengaged allowing free movement. When fully extended, the pawl engages with the capture bracket to lock the tiers vertically, eliminating motion and noise while maintaining operational smoothness during transitions.
Solution Approach 2:
The vertical clearance parameter between tiers is dynamically adjusted based on position. When extended, the interlock mechanism reduces vertical clearance to eliminate play. During retraction, clearance increases to allow smooth passage of tiers past each other, resolving the contradiction between stability and operability.
2Loss of energy
If camber is built into the frame to eliminate closing friction, then operational clearance is reduced, but deck bounce increases when lightly loaded
Solution Approach 1:
The pawl-capture bracket interlock mechanism acts as an intermediary that provides vertical stabilization without requiring camber in the frame structure. This mediator eliminates deck bounce by mechanically preventing excessive vertical movement, while allowing the frame to maintain its standard design without energy loss from friction.
3Reliability
If adjustable cantilevers are used to fine-tune operating clearance, then friction and bounce can be optimized, but device complexity and installation cost increase
Solution Approach 1:
The interlock mechanism is designed to self-adjust and self-lock automatically when the bleacher reaches its fully extended position. The pawl engages with the capture bracket without requiring manual adjustment or complex mechanisms, providing reliable vertical stabilization through the natural geometry of the components and the force of gravity.
4Ease of manufacture
If fixed camber is designed into frames, then manufacturing is simplified, but the same camber amount cannot accommodate varying deck weights and sizes
Solution Approach 1:
The solution segments the stabilization function from the frame structure itself. Instead of embedding camber adjustments throughout the frame, the interlock mechanism is a separate, modular component that provides adaptive vertical stabilization. This segmentation allows standard frame manufacturing while adding versatility through the adjustable interlock mechanism.
Data Source
AI summary
Apparatus for securing adjacent tiers of a retractable bleacher to prevent relative vertical movement between the adjacent tiers when the retractable bleacher is fully extended are described. The retractable bleacher includes a first engagement member that is secured to a first decking tier, a second engagement member secured to a second adjacent decking tier. The first engagement member and the second engagement member are configured and cooperative to prevent relative vertical movement of the second decking tier with respect to the first decking tier when the retractable bleacher is fully extended in the open configuration.