Airbag Cable Unwinding Device with Centrifugal Locking
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Solution Overview
Problem
Existing airbag actuation systems for motorcyclists are bulky, require frequent power verification, have complex communication needs, or suffer from delayed activation due to cable length limitations, necessitating a simpler, reliable, lightweight, and customizable solution for quick and effective airbag deployment.
Innovation Solution
A device controlling the unwinding of an airbag actuation cable featuring a movable element with a locking system using a helical spring and shaped element, which engages recesses upon exceeding a critical load, allowing quick locking of the cable and customizable response to stresses through adjustable mass placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flexible cable is used to activate the airbag filler, then the system is simple to construct, but the activation time is delayed due to the cable needing to extend to its maximum length
Solution Approach 1:
The actuation cable is pre-wound on a reel device in a compact configuration before activation. This preliminary winding state allows the system to achieve rapid cable deployment when activation occurs, eliminating the delay associated with cables that must extend from a fully extended state. The reel mechanism stores the cable in a condensed form ready for quick unwinding.
Solution Approach 2:
The system transitions from a static cable configuration to a dynamic reel-based mechanism that can rapidly change cable length. The reel device enables the cable to be wound and unwound dynamically, providing both compact storage and rapid deployment capabilities, thus resolving the contradiction between simple construction and fast activation.
2Reliability
If the cable is fixed between the vehicle and the airbag filler, then the system is reliable, but the cable requires maximum extension length which increases activation time
Solution Approach 1:
The cable is pre-positioned on the reel in a wound state, ready for rapid deployment. This preliminary configuration maintains system reliability through secure winding while enabling fast activation by eliminating the need for the cable to extend from maximum length.
Solution Approach 2:
The reel device acts as an intermediary mechanism between the fixed cable ends and the activation trigger. It mediates the cable deployment process by controlling the unwinding speed and ensuring reliable cable transmission from the wound state to the extended state, thus maintaining reliability while reducing activation time.
3Extent of automation
If electronic activation devices with sensors are used, then the airbag can be activated automatically, but the device becomes bulky and requires power supply verification
Solution Approach 1:
The system uses the motorcyclist's own pulling action on the cable as the activation trigger. This self-service mechanism eliminates the need for external sensors, power supplies, and electronic control systems, thereby reducing device complexity and bulk while maintaining automatic activation capability through the mechanical pull trigger.
Solution Approach 2:
The invention replaces electronic activation systems with a purely mechanical cable-pull mechanism. By substituting sensors, microcontrollers, and power supplies with a simple mechanical reel and cable system, the device achieves automatic activation without the bulk and complexity of electronic components.
4Reliability
If the cable length is increased to ensure full extension for activation, then the activation is reliable, but the device weight and dimensions increase
Solution Approach 1:
The actuation cable is nested within the reel device in a wound configuration. This nesting allows a long cable to be contained within a compact volume, ensuring that sufficient cable length is available for reliable activation while keeping the overall device weight and dimensions minimal. The cable is effectively hidden within the reel structure.
Solution Approach 2:
The cable is pre-wound on the reel in a compact nested state, ready for rapid deployment. This preliminary winding allows the system to have a long cable for reliable activation without the cable contributing to device weight during normal operation, as it is condensed within the reel.
5Weight of moving object
If the cable is made shorter to reduce device weight, then the device is lighter, but the cable cannot extend fully which compromises activation reliability
Solution Approach 1:
The cable is nested within the reel device, allowing a long cable to be contained in a compact form. This nesting enables the use of sufficient cable length for reliable activation while keeping the external dimensions and weight of the device minimal, as the cable is hidden within the reel structure during non-activation states.
Solution Approach 2:
The reel mechanism provides dynamic cable length adjustment, allowing the cable to be compact during normal use and fully extended during activation. This dynamic capability ensures that the cable can be short in terms of external dimension while still providing full extension length when needed, maintaining both weight efficiency and activation reliability.
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
Enables rapid and reliable airbag deployment with reduced weight and complexity, customizable sensitivity, and improved response time by utilizing Euler's principle of buckling to lock the cable before full unwinding, integrating seamlessly with protective garments.
Implementation Method 1
a blocking assembly (13, 14, 18) arranged on said second surface and comprising a helical spring (13), which works in compression
Implementation Method 2
the movable element (6) accelerates in rotation... the centrifugal force generated by such acceleration overcomes the compression performed by the spring on the shaped element (14)
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The present invention relates to a device (10) for controlling the unwinding of an actuation cable (2) of an airbag, comprising a main body (3) inside which a movable element (6) and a locking system of the movable element (6) are housed. The movable element (6) is rotatably arranged in said main body (3) and comprises winding devices, arranged on a first surface of the movable element (6), and configured to wind and unwind the actuation cable (2). The movable element (6) also comprises a retaining device (7) arranged on a second surface of the movable element (6) and configured to hold an end of the actuation cable (2). The locking system of the movable element (6) comprises a crown element (11), integral with the main body (3), and having a profile provided with a plurality of recesses (12) facing a second surface of the movable element (6), said second surface being arranged at one end of the movable element opposite the first surface. The locking system further comprises a blocking assembly, arranged on said second surface of the movable element (6), which comprises a helical spring (13) which works both in compression and upon reaching Euler's buckling load and which has at least one central portion free from constraints. The blocking assembly further comprises a shaped element (14) hinged to the movable element (6), which has an engagement section (15), adapted to engage said recesses (12), and a housing seat (17) in which a first end of the helical spring (13) is constrained; the housing seat (17) is arranged such that, when the cable is at rest, the thrust of the spring on the seat (17) maintains the engagement section (15) distant from said recesses (12). The blocking assembly further provides a matching element (18) in which a second end of the helical spring (13) is constrained.