Lifter Fall Prevention Mechanism for Chain Breakage
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Solution Overview
Problem
Conventional lifters for conveying devices are ineffective in preventing sudden lowering of the workpiece support base when elevation/lowering drive chains break, leading to potential accidents due to the fall prevention mechanism's inability to engage the ratchet pawls effectively during chain failure.
Innovation Solution
The lifter incorporates a lowering process forcible fall prevention mechanism with operating levers and a link mechanism that switches ratchet pawls to the engaged orientation mechanically against the actuator's driving force when a movement difference occurs between crosslink mechanisms, ensuring the pawls engage with the ratchet gears to prevent collapse, and utilizes sensors to detect pawl engagement for emergency stop control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fall prevention means uses ratchet pawls that are switched to unengaged orientations by actuators during lowering, then the lowering operation can be performed smoothly, but the fall prevention means becomes ineffective when the elevation/lowering drive chains break
Solution Approach 1:
The patent applies preliminary anti-action by providing a forcible fall prevention mechanism that preemptively counteracts the potential failure of the actuator-based fall prevention system. When drive chain breakage is detected, the ratchet pawl is forcibly engaged with the ratchet gear through the operating lever and link mechanism, creating a backup safety barrier that prevents uncontrolled lowering before the situation can deteriorate into an accident.
Solution Approach 2:
The patent implements beforehand cushioning by establishing a dual-layer fall prevention system where the first layer (actuator-controlled ratchet pawl) provides normal operation safety, and the second layer (forcible fall prevention mechanism) provides emergency protection. This layered approach ensures that if the primary fall prevention system fails, the secondary system is already in place to cushion against the harmful effect of uncontrolled lowering.
2Reliability
If the ratchet pawl is engaged with the ratchet gear to prevent lowering, then fall prevention is effective, but the lowering operation cannot be performed
Solution Approach 1:
The patent applies dynamics by creating a switchable fall prevention system where the ratchet pawl can dynamically change its state between engaged and disengaged orientations. During normal lowering operation, the actuator switches the ratchet pawl to the unengaged orientation, allowing smooth operation. When chain breakage is detected, the system dynamically transitions to the engaged orientation through the forcible fall prevention mechanism, providing adaptive safety based on operational conditions.
Solution Approach 2:
The patent segments the fall prevention function into two independent subsystems: the primary fall prevention means (actuator-controlled ratchet pawl) that handles normal operation, and the secondary forcible fall prevention mechanism (operating lever with link mechanism) that handles emergency situations. This segmentation allows each subsystem to be optimized for its specific function without interfering with the other, enabling both smooth operation and reliable safety.
3Adaptability or versatility
If the elevation/lowering drive chains are driven to lower the workpiece support base, then the base can be positioned at different heights, but sudden lowering can occur when the chains break
Solution Approach 1:
The patent implements feedback by establishing a detection system that monitors the operational status of the elevation/lowering drive chains and triggers the forcible fall prevention mechanism when breakage is detected. The system continuously senses the state of the drive chains and automatically activates the ratchet pawl engagement response when abnormal conditions occur, creating a closed-loop safety system that adapts to real-time operational conditions.
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
This configuration automatically restrains the collapsing crosslink mechanism at the broken chain side, preventing the workpiece support base from inclining excessively and ensuring safety by engaging the ratchet pawl with the ratchet gear, and allows for emergency stop of the elevation/lowering drive chains when a chain breaks, preventing accidents.
Implementation Method 1
ratchet pawls (38), moving horizontally in interlock with the respective movable support shafts (22a, 22b) and being engaged with the ratchet gears (37) by urging forces to deter lowering of the workpiece support base (14)
Implementation Method 2
a lowering process forcible fall prevention mechanism (46) which includes a pair of operating levers (47a, 47b) and a link mechanism (48 to 49b), where the pair of operating levers (47a, 47b) switch the respective ratchet pawls (38) in the unengaged orientations to engaged orientations of being engaged with the ratchet gears (37) against driving forces of the actuators (39)
Implementation Method 3
The link mechanism (48 to 49b) is such that, when a difference arises in movement amounts of the respective movable support shafts (22a, 22b) during lowering of the workpiece support base (14), it converts the movement amount difference to an operating force of the operating lever (47a/47b) at the larger movement amount side
Implementation Method 4
a pair of right and left actuators, which, when the workpiece support base is lowered, switch and hold the respective ratchet pawls against the urging forces to and in unengaged orientations of being separated from the ratchet gears
Data Source
AI summary
A lifter is provided with operating levers, which, against driving forces of actuators that switch the ratchet pawls to unengaged orientations, switch the ratchet pawls to engaged orientations of being engaged with ratchet gears, is provided with a link mechanism, which, when a workpiece support base is being lowered by collapsing motions of a pair of right and left crosslink mechanisms supporting the workpiece support base and a difference arises in movement amounts of movable support shafts at lower end sides of the respective crosslink mechanisms, converts the movement amount difference to an operating force of the operating lever at the larger movement amount side, and is such that by the operating lever at one side being driven by the link mechanism, the operating lever switches the ratchet pawl at the larger movement amount side to the engaged orientation.