Adjustable Backstay Spreader for Crane Jib Setup
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Solution Overview
Problem
High-capacity cranes face challenges in transporting and setting up jib backstay straps due to interference with boom hoist rigging, requiring a spreader to separate the straps, which is difficult to position at elevated heights during assembly.
Innovation Solution
An adjustable length backstay spreader with a pivoting joint connector and actuator that can be attached between backstay straps at ground level, allowing extension to separate the straps after they are raised, and featuring a locking mechanism to maintain the spread position during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the jib backstay straps are positioned close together during transport, then transportation efficiency is improved, but the straps interfere with the boom hoist rigging during operation
Solution Approach 1:
The spreader incorporates an adjustable length mechanism that allows it to dynamically change its dimensions. During transport, the spreader is in a retracted state keeping straps close together for efficiency. During operation, the spreader extends to spread the straps apart, preventing interference with the boom hoist rigging. This dynamic adjustment resolves the contradiction between transportation efficiency and operational safety.
2Object-affected harmful factors
If the spreader is positioned at elevated height to separate the backstay straps during operation, then strap interference is prevented, but the setup process becomes difficult and time-consuming
Solution Approach 1:
The spreader is pre-positioned at ground level attached to the backstay straps before the lifting operation begins. This preliminary positioning allows the spreader to be in place and ready to function as soon as the straps are raised, eliminating the need for workers to position it at elevated heights during the setup process, thus reducing setup time while still preventing strap interference.
3Reliability
If the backstay straps are spread apart to avoid contact with boom hoist rigging, then operational safety is improved, but the transport configuration becomes more complex
Solution Approach 1:
The spreader's adjustable length mechanism allows it to adapt its configuration dynamically. In transport mode, the spreader is in a compact retracted state that maintains simplicity. In operational mode, the spreader extends to provide the necessary strap separation for safety. This dynamic capability ensures operational safety without permanently increasing transport configuration complexity.
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 easy setup and operation by allowing the spreader to be attached and extended at a lower height, preventing strap interference with boom hoist rigging, even when loads are lifted, simplifying crane assembly and operation.
Implementation Method 1
pivoting joint connectors being used to hold the first and second members together with a pivotal connection
Implementation Method 2
an actuator mounted between the pivoting joint connectors; wherein the actuator controls the angle between the extending portions
Data Source
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AI summary
A backstay spreader (51) attachable between a pair of backstay sections on a crane includes first and second members (52, 53) each having a backstay section connector (54, 55) at a first end and a pivoting joint connector (56, 57) at a second end, the pivoting joint connectors (56, 57) being used to hold the first and second members (52, 53) together with a pivotal connection and each having an extending portion extending away from the pivotal connection, with an angle between the extending portions. The backstay spreader (51) also includes an actuator (83) mounted between the pivoting joint connectors (56, 57). A method of setting up a lift crane (10) includes the steps of attaching a boom to a rotating bed and a strut (29) to the boom (22); attaching jib backstay straps (33) between the strut (29) and the rotating bed (20) ; attaching an adjustable length spreader (51) between the jib backstay straps (33), the spreader (51) having a first length when being attached between the jib backstay straps (33); and extending the length of the spreader to a second length longer than the first (51) length after the spreader (51) is attached between the jib backstay straps (33).