Crash Cushion Side Panel Attachment via Slider Bolt and Spacer Shim
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Solution Overview
Problem
Existing crash cushion systems face challenges in securely attaching side panels to supports while allowing for controlled telescoping collapse upon vehicle impact, as improper torque can lead to loose attachment or premature bending/breaking of panels.
Innovation Solution
The crash cushion employs a novel fastener assembly with spacer shims and slider bolts that maintain a gap between side panels, allowing for even and controlled collapse, using corrugated steel side panels with parallel slots and reinforcing cables to facilitate accordion-style energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bolts are torqued tightly to securely attach side panels to supports, then attachment strength is improved, but side panels cannot slide and telescope together properly during collapse
Solution Approach 1:
A slider assembly acts as an intermediary component between the side panel and support. The slider includes a bolt that passes through a slot in the side panel and engages with the support, allowing the panel to slide vertically along the bolt while maintaining secure attachment. This mediator enables both strong attachment and controlled movement during cushion collapse.
Solution Approach 2:
The attachment system transitions from a static rigid connection to a dynamic connection that allows controlled movement. The slot in the side panel and corresponding engagement feature in the support create a mechanism that permits vertical sliding motion while maintaining lateral attachment, enabling the side panels to telescope together during impact absorption.
2Ease of operation
If bolts are torqued loosely to permit sliding, then telescoping capability is improved, but side panels become too loosely attached and move inadvertently
Solution Approach 1:
The slider assembly serves as a mediator that provides stable attachment while enabling controlled movement. The bolt passing through the slot engages with the support structure, preventing inadvertent movement while allowing deliberate telescoping motion during cushion deployment.
Solution Approach 2:
The attachment system is segmented into distinct functional components: the slot in the side panel, the slider assembly with bolt, and the engagement feature in the support. This segmentation allows independent optimization of each component - the slot provides movement freedom while the bolt and engagement feature provide stable attachment.
3Strength
If side panels are attached rigidly to supports, then structural integrity is improved, but crash cushion cannot collapse in accordion fashion upon impact
Solution Approach 1:
The attachment system is designed to be dynamic rather than rigid, allowing the side panels to move relative to the supports during impact. The slot-bolt mechanism enables the structure to transition from a rigid assembled state to a collapsing accordion state, providing both structural integrity during handling and collapse capability during impact.
Solution Approach 2:
The side panels are pre-configured with slots and the slider assemblies are pre-installed to enable collapse functionality before impact occurs. This preliminary preparation ensures that when impact occurs, the panels can immediately begin telescoping together in the intended accordion fashion without requiring additional adjustment or force.
Data Source
AI summary
A crash cushion includes a number of spaced-apart supports or bulkheads, energy-absorbing modules positioned between the supports; and overlapping side panels that interconnect the supports and envelop the energy-absorbing modules. The crash cushion collapses upon itself in an accordion fashion when struck by a vehicle so as to transfer and absorb vehicle impact energy over a predetermined distance. The side panels are attached to the supports and to each other with fastener assemblies. Each fastener assembly comprises a slider bolt, a nut, and a spacer shim. The spacer shim maintain gaps between the slider bolts and the side panels so that the overlapping edges of adjacent side panels are not compressed together regardless of the torque applied to the slider bolt to allow the side panels to collapse and telescope together smoothly when the crash cushion is struck by a vehicle.