Vehicle Carrier End Support Tunable Clamping Force
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Solution Overview
Problem
Vehicle article carrier systems face challenges in providing sufficient clamping force to secure cross bars during crash events due to variations in support rail dimensions and elastomer thickness, while also requiring easy user operation without external tools, which has not been achievable without a locking pin.
Innovation Solution
The system includes end supports with a fixed jaw portion, a movable jaw portion, an actuating lever, and a pivot component with a threaded barrel nut, allowing for adjustable clamping force by changing the effective distance between the jaw portions, eliminating the need for a locking pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional locking pin mechanism is used to secure end support to support rail, then crash test requirements are met with sufficient clamping force, but device complexity increases and user operation becomes difficult without external tools
Solution Approach 1:
The locking pin mechanism is completely removed from the end support design. Instead, the patent uses a adjustable clamping mechanism with a cam lever that applies sufficient clamping force through friction alone, eliminating the need for positive locking pins while meeting crash test requirements.
Solution Approach 2:
The patent introduces adjustability in the clamping force through a threaded rod mechanism that allows the clamping pressure to be tuned. This parameter change enables the system to achieve sufficient friction-based holding force without requiring complex locking pins, thereby simplifying the overall device while maintaining reliability.
2Reliability
If higher clamping force is applied by end support, then cross bar security during crash events is improved, but ease of operation deteriorates as user manipulation becomes difficult
Solution Approach 1:
The patent employs a cam lever mechanism that provides dynamic mechanical advantage. When the user applies force to operate the lever, it translates into significantly higher clamping force on the support rail. The lever can be easily operated by hand to achieve secure clamping, and includes a detent mechanism that maintains the clamped position without requiring continuous user force.
Solution Approach 2:
The cam lever acts as an intermediary between user input and the clamping force application. It amplifies the user's manual force into sufficient clamping pressure while remaining easy to operate, and includes a spring-loaded detent that mediates the holding function, allowing easy one-handed operation while maintaining secure clamping.
3Reliability
If clamping force is increased beyond minimum requirements, then crash test compliance is ensured, but manufacturing precision requirements increase due to sensitivity to dimension variations
Solution Approach 1:
The patent introduces adjustability in the clamping force through a threaded rod mechanism that allows the clamping pressure to be tuned. This parameter change enables the system to compensate for variations in support rail dimensions and elastomer thickness, ensuring consistent performance without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The adjustable mechanism transforms a static clamping system into a dynamic one where the clamping force can be adapted to match actual support rail dimensions. This allows the system to maintain optimal performance across a range of manufacturing variations without requiring precise dimensional control.
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 adjustable clamping force meets crash test requirements while allowing easy user operation, securing the cross bar without sliding during impacts and accommodating variations in support rail dimensions and elastomer thickness.
Implementation Method 1
A threaded member is included which is coupled to both the barrel nut and the pivot component. The threaded member enables changing an effective distance between the bore of the movable jaw portion and the pivot component
Implementation Method 2
slight variations in the thicknesses of rubber or elastomer layer surfaces which are often applied to the clamping surfaces of the end support components
Implementation Method 3
rubber or elastomer layer surfaces which are often applied to the clamping surfaces
Data Source
AI summary
The present disclosure relates to a vehicle article carrier system for supporting articles above an outer body surface of a vehicle. The system makes use of a pair of support rails fixedly secured generally parallel to one another on the outer body surface, and at least one cross bar assembly clampable to the support rails, and having a cross bar element having opposing ends. First and second end supports are secured at the opposing ends and able to engage the support rails to secure the cross bar against movement on the support rails. At least one of the end supports includes fixed and movable jaw portions, an actuating lever, and a pivot component pivotally coupled to the actuating lever and including a bore. A barrel nut is positioned in a bore of the movable jaw portion. A threaded member is coupled to both the barrel nut and the pivot component for changing an effective distance between the bore of the movable jaw portion and the pivot component, to thus effectively change a clamping force able to be applied by the movable jaw portion relative to the fixed jaw portion when the actuating lever is moved into a closed position.