Huagong's grabs

Grab bucket is a special tool used by cranes to grab dry bulk materials. It consists of two or more bucket jaws that can be opened and closed to form a space to hold the material. When loading, the jaws are closed in the material pile and the material is caught in the space. It is the main tool for handling dry bulk cargo in ports, as it is free from heavy physical labour and can achieve high loading and unloading efficiency and ensure safety. According to the type of cargo, it can be divided into ore grabs, coal grabs, grain grabs, timber grabs, etc.

Grapple classification

Classification by shape

By shape, they can be divided into shell grabs, which consist of two complete buckets, and orange-flap grabs, which consist of three or more jaws.

Classification by driving method

According to the driving method can be divided into hydraulic grab and mechanical grab two categories.

I. Hydraulic grapple

The hydraulic grab itself is equipped with an opening and closing structure, generally driven by hydraulic cylinders, and is also called a hydraulic claw, consisting of multiple jaws. Hydraulic grabs are widely used in hydraulic special equipment, such as hydraulic excavators, hydraulic lifting towers, etc.

The hydraulic grab is a hydraulic structural component product, consisting of hydraulic cylinders, buckets (jaws), connecting columns, bucket lug plates, bucket lug sleeves, bucket teeth, tooth holders and other spare parts, so welding is the most critical production process for the hydraulic grab, and the quality of the welding directly affects the structural strength and service life of the hydraulic grab. In addition, the hydraulic cylinder is also the most critical driving component.

The hydraulic grab is a special industry component and requires special equipment for high efficiency and quality work, such as CNC plasma cutting machines, bevel milling machines, plate rolling machines, welding shifters, boring machines, hydraulic test benches, etc.

Excavator-specific hydraulic grabs are divided into two types: rotary and non-rotary, without rotary grabs using the oil circuit of the excavator bucket cylinder, without additional hydraulic valves and pipelines; with rotary grabs to add a set of hydraulic valves and pipelines to control.

Excavator-specific hydraulic grabs are suitable for the following applications.

1、Building foundation excavation, deep pit excavation and loading of mud, sand, coal and gravel.

2、Particularly suitable for digging and loading on the side of ditch or restricted space.

3、It is suitable for loading and unloading of ships, trains and automobiles.

Mechanical Grab Bucket

Mechanical grab itself is not configured to open and close the structure, usually by the rope or linkage external drive, according to the operating characteristics can be divided into double rope grab and single rope grab, the most commonly used is the double rope grab.

Double rope grabs have a support rope and an opening/closing rope, which are wound around the reel of the support and opening/closing mechanism respectively. The double rope grab is reliable, easy to operate, highly productive and widely used. With two sets of double ropes it becomes a four-rope grab and works in the same way as a two-rope grab.

Single rope grab The same wire rope is used for the support rope and the opening and closing rope. A special locking device allows the rope to be used in turn as a support and opening/closing rope. The single rope grab has a simple winding mechanism, but the productivity is low and rarely used for large quantities of loading and unloading operations.

Grab according to the density of the material being grabbed and divided into light (such as grabbing grains), medium (such as grabbing gravel) and heavy (such as grabbing iron ore) 3 categories; according to the number of jaws divided into double jaw grab and multi-jaw grab, the most commonly used is the double jaw grab. For large pieces of ore, iron ore and scrap steel, etc. should be used multi-jaw plate grapple, because it has a multi-claw, cutting edge characteristics, easy to insert into the pile, can get a better gripping effect.