Retractable Anti-Underrun Device with Torsion Spring Synchronization
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Solution Overview
Problem
Existing retractable underrun prevention devices for vehicles are prone to component complexity and vulnerability to external blockages, which can cause the bumper to move beyond the vehicle's side profile during folding or deployment operations.
Innovation Solution
A retractable underrun prevention device with torsion springs located around the axes of rotation of the arms, a single-rod double-acting hydraulic cylinder actuator mounted between the front arms, and adjustable arm lengths to maintain the bumper within the vehicle's side profile, along with elastic locking means to secure the bumper in position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tension springs are used to connect the rear arms to the bumper, then the arms can be synchronized during folding and deployment, but the device becomes vulnerable to blocking by external objects stuck in the spring turns
Solution Approach 1:
The patent extracts the springs from their traditional position connecting the bumper to the arms, and relocates them to the rotation axes of the arms only. This separation removes the vulnerability point where objects could get stuck between the bumper and springs, while preserving the synchronization function through the torsion springs at the axes.
Solution Approach 2:
Instead of using springs to pull the bumper toward the arms (traditional configuration), the invention inverts the approach by placing springs at the rotation axes to control the arm rotation itself. This reverses the mechanical advantage direction and eliminates the blocking vulnerability while maintaining synchronization.
2Reliability
If multiple components are used for synchronization, then the arms can be coupled during folding and deployment, but the device complexity increases with a large number of components
Solution Approach 1:
The patent merges the synchronization function into the arm rotation mechanism itself by placing torsion springs directly at the rotation axes. This eliminates the need for separate synchronization components like guide rods and tension springs, reducing the total component count while maintaining the synchronization capability through the integrated spring-axle system.
3Ease of operation
If the bumper is allowed to move freely during folding operations, then the device can be retracted, but the bumper may move beyond the side clearance of the vehicle
Solution Approach 1:
The torsion springs at the arm rotation axes provide continuous mechanical feedback that resists unauthorized movement of the bumper. As the arms fold and the bumper moves, the springs automatically generate restoring forces that prevent the bumper from exceeding its designated clearance envelope, creating a passive feedback control system.
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 solution provides a robust, simple, and less vulnerable device that ensures the bumper remains inside the vehicle's side profile during operations, minimizing the risk of external blockages and component complexity, while allowing adjustable arm lengths for various vehicle configurations.
Implementation Method 1
at least four torsion springs (9), arranged around the axes of rotation of the arms (4a, 4b; 5a, 5b)
Implementation Method 2
an actuator (8) capable of pivoting the front arms (4a, 4b) around their axes of rotation
Implementation Method 3
said locking means is integral with the crosspiece (2) and comprises at least one elastic blade having a boss cooperating with a hole in the bumper
Data Source
Figure 1~2
Figure 3~4
Figure 5~9
AI summary
The device has a bumper (3) connected to a crossmember (2) via U shaped front and rear arms (4a, 5a) and front and rear arms (4b, 5b). The front arms are pivotingly mounted around axles (40a, 40b) connected to the crossmember, and the rear arms are pivotingly mounted around axles (50a, 50b) connected to the bumper. An actuator (8) i.e. single rod type double-acting hydraulic cylinder, pivots the arms. Torsion springs e.g. helical springs, are arranged around the axles to rotate the arms to maintain the same rotational angle for the arms during the deployment and folding of the device.