【JST-100】 One-on-one Special Lecture on Lifting and Hoisting

For the lifting of some tall towers, chimneys, or structures, if there is no ladder to climb to the top in order to remove the hook, how can the hook be removed then?

This post was last edited by Shutong on 2015-3-29 00:07. This is a quite sophisticated question; I’ll provide a detailed answer on Monday: lol. Essentially, this problem relates to removing hooks from high places. Since the topic has been brought up, I’ll first discuss other scenarios, addressing the question in post 2 at the end. Let’s start with the first scenario: unloading using a single hook. Automatic hook removal devices are designed to overcome the drawbacks of using ordinary single hooks for loading and unloading goods – namely, the need for manual effort to remove the hooks, which is time-consuming, labor-intensive, and unsafe. Such devices consist of a hook body used to grasp the goods, along with a stopper that blocks the hook opening. The hook body is mounted inside a box-shaped casing; between the top wall of the casing and the hook handle, there is a lifting arm whose upper part extends outside the casing while its lower part can slide up and down inside the casing. The two ends of a compression spring are seated between the lifting arm and the top wall of the casing； Below the bottom surface of the boom, there is also a cam and ratchet mechanism assembly that allows the hook opening to lock upward when bearing load, and to open automatically when unloading. Thanks to the cam and ratchet mechanism built into the hook, which allows the hook mouth to lock in an upward position when bearing load and to open automatically when the load is removed, the hook body disengages automatically during unloading, separating the load from the person. This prevents multiple lifting devices from getting hooked together again, resulting in savings in labor, effort, and time. It is safe, reliable, efficient, and reduces the costs associated with loading and unloading. Turning to the second type of hook removal for cranes: large-scale lifting equipment equipped with cranes, and in particular, it relates to an automatic device for attaching and removing the main hook boom of such large-scale lifting crane equipment ； It is characterized in that front and rear linkage mechanisms are symmetrically installed on the outer sides of the middle sections of the boom mechanisms on the left and right sides; each side’s linkage mechanism consists of a pin shaft, a linkage rod shaft, a shaft sleeve, a linkage rod sleeve, a linkage rod head, an A linkage rod, and a B linkage rod ； Self-locking and unlocking mechanisms for two linkage systems are symmetrically installed at both ends of the connecting rod shaft; each such self-locking and unlocking mechanism consists of an upper connecting sleeve, an end cover, a sliding rod, spring B, a pin, spring A, a lower connecting sleeve, a T-shaped lock head, a lock slot, and a cam-type crank mechanism ； A cam-type crank mechanism is installed in each self-locking release mechanism. It features a rational design that allows the boom to open and lock freely, enabling automatic attachment and detachment. It is also safe and easy to operate, saving time and effort while being very convenient to use. Continue tomorrow

The third type is the tubular lifting lug: when lifting large equipment, the steel wire rope passes through the hook and is attached to the neck of the lifting lug. Once the equipment is in place and the anchor bolts have been used to secure it, the crane hook can be lowered, and the steel wire rope will disconnect naturally; thus, there is no need for anyone to climb to a high place to remove the hook

I was about to ask that same question; you got there first. ------------------------------------------ It’s easy to connect, but hard to disconnect. Could it be a lift cage? But lifts are not allowed in many places

It’s still the same question: you mean that the steel cable comes loose on its own. If the tower is several dozen meters tall, the cable itself is quite heavy – isn’t that very dangerous? It would be best if Shutong could provide some photos

Desert Boss: The crane arms of large-scale equipment are taller than the equipment itself, so there is no need for the steel cables to be as long as the equipment. This is especially true in cases where balance beams are used; the steel cables don’t need to be very long. Once the lifting is complete and the arm is retracted, you know how to remove the hook

The method of removing the hook from the lift cage can be explored. Anyway, I’ve seen it used in many projects. Its safety is ensured by the reliability of the crane, hoist cage, and other accessories, as well as proper operating procedures. I have discussed this with construction experts abroad, and this method is also used for lifting work in projects there.

Under normal circumstances, the crane’s boom is on the same horizontal line as the obstacle, and in such cases CAD can be used to directly measure the distance from the boom to the obstacle. How can one calculate the distance between a crane’s boom and an obstacle when there is a certain angle between them?

Where is the person? Where is the person? Where is the person? Where is the person? Where is the person? Where is the person? Where is the person?