Rope-Operated Orange Peel Grab Fabrication

The job

A rope-operated (mechanical) orange peel grab for a crane handling scrap and bulk material: several curved, pointed tines; a rope arrangement working between upper and lower sheave groups to open and close the tines; pivot pins and bushings; a maximum-load marking on the body. The photo shows the grab in the workshop, tines open, fully painted.

Design decisions

Tine geometry follows the material: for irregular, hookable loads such as scrap, pointed curved tines grip better; for bulk material a more closed tip is preferred. Tine count and open diameter are chosen together with the crane's lifting capacity and the material density — the loaded grab must stay within the crane's limit.

Rope drive: on two-rope cranes no power supply is needed; the closing rope pulls the sheave group to close the tines while the holding rope carries the grab. Sheave diameter and rope path govern rope life.

Wear and maintenance: tine tips and rubbing surfaces are made from wear-resistant plate; pins and bushings are designed for replacement in the field, and grease points are kept accessible.

How it was built

• Tines and arms were cut from plate and welded into box sections; welds in fatigue-loaded zones were full penetration.
• Pivot bores were machined, bushings fitted; sheaves and rope path installed and the open-close motion tested in the shop.
• Surfaces were blast-cleaned and finished in orange topcoat; the maximum-load marking was applied.
• As a rope-operated grab falls under the lifting-accessory class, the technical file and inspection documents were prepared to the scope agreed in the contract.

Result

The grab was completed ready to hang on the crane and go to work, shop-tested and painted. Capacity, tine count, open/closed diameter and end-user details will be added to this page from the firm's form.