1.Grab Type Selection Reference：

Grab Bucket is more used for disperses the shape material handling, in the selection of material should be refer to physical performance, the accumulation concentration, block size, particle shape, the internal friction degree of materials and the loose degree, etc. According to the different packing density and block size, grab bucket is divided into light, medium, heavy and super- heavy.

Grab materials block degrees is more than 60 mm or more solid materials, the capture cutting edge should be made tooth.

Grab type selection table:

Material Packing density(specific gravity)    ＜1.2 t/m3         1.25-2.0 t/m3         2.0-2.8 t/m3              ＞2.8 t/m3

Match Grab type                                         Light type           Middle type            Heavy type                 Over Heavy type

2.The rate of opening and closing rope pulley powerful matching

The rate of the opening and closing rope of pulley and the closing force of the grab is directly proportional to the relationship. The smaller rate, the faster closed speed, but it can cause grasping force insufficient. 

The bigger rate, the slower closed speed and exacerbate the opening and closing rope wear.

The pulley of the grab mapping table:

Grab type         Light type       Middle type      Heavy type      Over Heavy type

Pulley rate         3-4                 4-5                   5-6                   6-8