Toy Crane Rope Drum Anti-Twist Safety Mechanism
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Solution Overview
Problem
Existing toy cranes with rope drums lack a reliable and simple mechanism to secure the drum body against rotation relative to the frame, limiting their functionality and safety during use.
Innovation Solution
A cable drum with a safety device featuring a crank that can be adjusted between a locked and unlocked position, using a locking cam and elastic spring tongue for secure engagement and overload protection, allowing easy handling and preventing unintended position changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple mounting of the drum body on the frame is used, then the ease of manufacture is improved, but the reliability of securing the drum body against rotation deteriorates
Solution Approach 1:
The safety device is segmented into distinct functional components: a locking cam with lateral locking lugs, a guide element with corresponding recesses, and an elastic spring tongue. This segmentation allows each component to be manufactured separately with simple geometries while collectively providing reliable anti-rotation functionality when assembled.
Solution Approach 2:
The elastic spring tongue automatically engages the locking cam with the guide element when the drum body is mounted, providing self-locking functionality without requiring additional fastening operations or complex adjustment procedures, thus maintaining ease of manufacture while ensuring reliability.
2Reliability
If a locking mechanism is added to secure the drum body, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The anti-rotation function is extracted as a separate safety device from the main drum body structure. The locking cam is integrated into the drum body while the guide element is mounted on the frame, separating the locking mechanism from the winding function and minimizing interference with the main crane structure.
Solution Approach 2:
Instead of using a complex multi-component locking mechanism, the invention inverts the approach by using a simple elastic tongue that passively engages with the locking cam through elastic deformation. The spring tongue naturally seeks to engage the locking position, reversing the typical active locking approach and reducing complexity.
3Ease of operation
If the crank can be easily adjusted between locked and unlocked positions, then the ease of operation is improved, but the reliability of maintaining the locked position deteriorates
Solution Approach 1:
The crank arm features a curved guide path within the guide element, allowing smooth radial displacement between locked and unlocked positions. This curved geometry provides intuitive tactile feedback to the user while ensuring reliable engagement at both extreme positions through the corresponding recesses in the guide element.
Solution Approach 2:
The elastic spring tongue provides cushioning and damping during the transition between locked and unlocked positions, absorbing shocks and preventing unintended position changes. This beforehand cushioning ensures that the crank remains securely in the selected position even during cable tension fluctuations.
4Reliability
If a fixed locking position is implemented, then the reliability is improved, but the adaptability of the drum body deteriorates
Solution Approach 1:
The safety device transitions from a static fixed locking mechanism to a dynamic system where the crank can be radially displaced to switch between locked and unlocked positions. The elastic spring tongue dynamically adjusts during transitions, while the guide element provides predetermined stable positions, combining reliability with operational flexibility.
Solution Approach 2:
The crank serves multiple functions: it acts as both the winding handle and the actuator for the safety device. By radially displacing the same crank arm, the operator can both wind the cable and engage/disengage the locking mechanism, eliminating the need for separate controls and enhancing versatility without compromising safety.
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 secure, user-friendly, and flexible mechanism for winding and unwinding cables, ensuring safety during operation and preventing damage from overloads, making it suitable for children and enhancing gameplay experience.
Implementation Method 1
a corresponding design of an elastic spring tongue, it is possible to set the critical cable force for overcoming the overload protection of the cable drum
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The drum (5) has a drum body (7) mounted at a frame (9) for rolling a rope. A crank (12) is connected with the drum body in a torque-proof manner for rotation of the drum body around a longitudinal axis (6). A safety device is provided as an anti-twist plate of the drum body relative to the frame. The safety device is implemented in such a manner that the crank is shiftable between a locking position and an unlocking position by a radial pulling of a crank arm (14) of the crank relative to the longitudinal axis. The safety device has a lock arm firmly connected with the crank arm.