Spare Wheel Safety Device with Locking Arm Mechanism
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Solution Overview
Problem
Existing spare wheel pick-up systems in motor vehicles are prone to cable failure due to vibrations and improper tightening, leading to the risk of the spare wheel falling, as the cable can unwind or snap, and existing safety devices are inadequate in preventing such incidents, especially during vehicle movement over road irregularities.
Innovation Solution
A safety device featuring a longitudinally movable support shaft within a hollow sleeve and a pivotable arm with a coupling section and locking means that prevents the arm from moving out of its first position, ensuring continuous engagement with the support shaft and thus securing the spare wheel, even when the cable snaps or comes off the drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cable is used to raise and lower the spare wheel, then the wheel can be easily positioned, but the cable may unwind or snap due to vibrations, causing the wheel to fall
Solution Approach 1:
The arm acts as an intermediary safety mechanism between the cable and the support shaft. When the cable fails (unwinds or snaps), the arm with its coupling section engages with the limitation means on the shaft, providing a backup connection that prevents the wheel from falling while maintaining the ease of cable-based positioning during normal operation.
Solution Approach 2:
The arm is pre-positioned in the first position where the coupling section is ready to engage with the limitation means on the shaft. This preliminary positioning ensures that if cable failure occurs, the safety mechanism is already in place and can immediately prevent the wheel from falling without requiring additional activation steps.
2Adaptability or versatility
If the arm is made pivotable to allow movement between positions, then the device can adapt to different states, but the arm may move out of position due to road irregularities when the cable snaps, causing the wheel to fall
Solution Approach 1:
The locking means provide a preliminary anti-action force that counteracts any forces trying to move the arm out of the first position. When road irregularities occur, the locking means prevent the arm from pivoting away from its engagement position with the limitation means, ensuring continuous support for the shaft and wheel even when the cable fails.
Solution Approach 2:
The arm is designed to be pivotable (dynamic) to allow it to assume different positions during normal operation, but the locking means introduce a constraint that stabilizes it in the critical first position when needed. This combination of dynamics and constraint allows the system to adapt to different states while maintaining reliability when required.
3Reliability
If locking means are added to prevent arm movement, then the arm remains engaged with the shaft, but the device complexity increases
Solution Approach 1:
The locking function is extracted as a separate, dedicated component (locking means with projection and recess) rather than being integrated into the arm or shaft structures. This extraction allows the locking mechanism to be simple and focused on its single function of preventing arm movement, minimizing the increase in overall device complexity while maximizing reliability.
Data Source
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AI summary
Safety device for a spare-wheel pick-up system, comprising a sleeve (1) with a window (10), a support shaft (2) fixed to the cable, which is housed in the sleeve (1) and which is longitudinally movable in the interior of said sleeve (1), and an arm (4) with a coupling section (40), disposed outside the sleeve (1) and pivotable in relation to an axis of rotation (5) between a first position (P1) in which the coupling section (40) passes through the window (10) of the sleeve (1) and a second position in which said coupling section (40) is retracted in relation to said window (10). The device also comprises locking means adapted to prevent, when in the first position (P1), the arm (4) from moving from said first position (P1) to the second position when the cable snaps.