Hinged Hoist Pull-Limiting Device With Elastic Means
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Solution Overview
Problem
Existing hoist pull-limiting devices are complex and expensive, requiring sophisticated mechanisms such as strain gauge load cells, slide devices, connecting rod devices, and deformation detection systems to discontinue hoist operation when a predetermined pull is exceeded.
Innovation Solution
A simpler and cost-effective pull-limiting device using a pair of steel plates hinged together with pre-loaded elastic means, where the rotation of the plates due to load is detected by a microswitch or proximity sensor to emit a signal that discontinues the hoist operation when the maximum pull is reached, utilizing elastic elements like Belleville washers or coil springs arranged at various distances from the hinge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pull-limiting devices (strain gauge load cells, slide devices, connecting rod devices) are used, then reliable pull detection is achieved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the essential function of pull detection from complex conventional devices and implements it through a simple hinged plate mechanism with elastic means. Instead of using strain gauges, load cells, or connecting rods, the invention uses a hinged plate assembly where the hinge angle directly indicates the pull force, eliminating the need for sophisticated sensing mechanisms while maintaining reliable detection capability.
Solution Approach 2:
The patent creates a simplified mechanical model that copies the essential measurement function of complex devices. The hinged plate mechanism replicates the pull detection function by using geometric relationships (hinge angle) rather than electronic sensors, achieving the same operational outcome with dramatically reduced complexity.
2Measurement precision
If sophisticated detection mechanisms (strain gauges, load cells, deformation sensors) are used, then precise pull measurement is achieved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, precision-manufactured sensing components with inexpensive mechanical elements. The hinged plate mechanism uses simple steel plates and standard elastic components (springs or Belleville washers) that are far cheaper than strain gauges or load cells, while the hinge angle provides sufficient measurement precision for operational control.
Solution Approach 2:
The patent changes the measurement parameter from electronic signal output (in conventional devices) to mechanical angle output (in the hinged plate mechanism). This parameter change allows the use of simple mechanical components instead of expensive electronic sensors, improving manufacturability while maintaining measurement capability through geometric relationships.
3Ease of operation
If fixed pull-limit settings are used, then simple device operation is maintained, but adaptability to different load requirements decreases
Solution Approach 1:
The patent introduces dynamic adjustability to the hinged plate mechanism by allowing the elastic means to be repositioned at different locations along the plate. This dynamic configuration enables the same basic mechanism to adapt to different pull force requirements by simply changing the position of the elastic component, maintaining operational simplicity while achieving versatility.
Solution Approach 2:
The patent designs the hinged plate mechanism to serve multiple functions: it detects pull force, indicates magnitude through hinge angle, and can be adjusted for different load requirements. The universal design allows a single device type to handle various operational requirements by adjusting elastic component position, eliminating the need for multiple specialized devices.
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 cost-effective and adjustable means to limit hoist pull, offering simplicity and versatility in detecting and signaling excessive load, allowing for easy adjustment and reduced operational costs compared to traditional devices.
Implementation Method 1
pre-loaded elastic means, consisting of Belleville washers or, alternatively, of coil springs
Implementation Method 2
pre-loaded elastic means, consisting of Belleville washers or, alternatively, of coil springs arranged at a predetermined distance from the hinge axis
Data Source
AI summary
A hoist (19) pull (P) limiting device (11), comprising: a first bearing element (14) to which the hoist (10) is fastened; a second bearing element (18) fastened to the bearing structure (24) on which the pull strength (P) acting on the hoist (10) is unloaded; a butt hinge (16) connecting the first (14) and the second (18) bearing elements with each other, the hinge (16) axis being substantially perpendicular to the direction wherein, through rope (22) of the hoist (10), the pull (P) acts on the latter, said axis being at a certain distance from the rope (22) leaving the hoist (10) drum; elastic means (20; 20A; 20.1; 20.1A) suitable to oppose the rotation of the first bearing element (14) away from the second bearing element (18) on account of the pull (P); means (28) suitable to detect when the width of the rotation angle (f) of the first bearing element (14) relative to the second bearing element (18) matches the maximum predetermined pull (P), as well as to emit the relevant signal.