Four rope grab

Four rope grab

Grab refers to the special tool for crane to grab dry and bulk goods. The container space is composed of two or more bucket shaped jaw plates that can be opened and closed. When loading, the jaw plate is closed in the material pile, and the materials are grabbed into the container space. When unloading, the jaw plate is opened when the material pile is suspended, and the materials are scattered on the material pile. The opening and closing of the jaw plate is generally controlled by the steel wire rope of the lifting mechanism of the crane. Grapple operation has no heavy physical labor, which can achieve high loading and unloading efficiency and ensure that it is the main dry bulk cargo loading and unloading tool in the port. According to the type of operation goods, it can be divided into ore grab, coal grab, grain grab, wood grab, etc.

Product classification

According to the driving mode, it can be divided into hydraulic grab and mechanical grab.

1、 Hydraulic grab

The hydraulic grab itself is equipped with an opening and closing structure, which is generally driven by a hydraulic cylinder. The hydraulic grab composed of multiple jaw plates is also called a hydraulic claw. Hydraulic grab is widely used in hydraulic special equipment, such as hydraulic excavator, hydraulic lifting tower, etc.

Hydraulic grab is a product of hydraulic structural parts, which is composed of hydraulic oil cylinder, bucket (jaw plate), connecting column, bucket ear plate, bucket ear sleeve, bucket tooth, tooth seat and other parts. Therefore, welding is the key manufacturing process of hydraulic grab, and the welding quality directly affects the structural strength and service life of hydraulic grab. In addition, the hydraulic cylinder is also a key driving component.

Hydraulic grab is a special industry equipment accessory, which requires special equipment to improve the rate and quality of operations, such as: CNC plasma cutting machine, groove milling machine, plate bending machine, welding positioner, boring machine, hydraulic test bench, etc.

2、 Mechanical grab

Mechanical grab has no opening and closing structure, and is usually driven by external force of rope or connecting rod. According to the operating characteristics, it can be divided into double rope grab and single rope grab, and double rope grab is commonly used.

Double rope grab

There are support ropes and opening and closing ropes, which are wound on the drums of the support mechanism and the opening and closing mechanism respectively. Figure 1 shows the working process of the double rope grab: a means that the support rope and the opening and closing rope descend at the same time, and open the bucket mouth to insert the pile. B to tighten the opening and closing rope, the jaw plate closes and grabs the material. C means that the support rope and the opening and closing rope rise at the same time after the grab is closed. D. in order to keep the support rope stationary, the opening and closing rope drops, the bucket mouth opens and the material is unloaded. The double rope grab has the advantages of reliable operation, simple operation, high productivity and wide application. After using two groups of double ropes, it becomes a four rope grab, and the working process is the same as that of the double rope grab.

Single rope grab

The support rope and the opening and closing rope use the same steel wire rope. The special locking device enables the steel wire rope to support and open and close in turn. The winding mechanism of single rope grab is relatively simple, but its productivity is low, and it is rarely used in a large number of loading and unloading operations.