Working Principle of Single Rope Grab for Crane

What is single rope grab?

• Single-rope grab is a kind of grab commonly used for cranes, generally composed of hanging beam/ring, wire rope, sliding slide bar, upper bearing beam, slide frame group, lower riding beam, brace bar, bucket part and so on.
• Single rope grabs mainly rely on the interaction of the sliding blocks, bumps, grooves and thimble of the grab to complete the unloading process.

Single-rope crane grab structure drawing:

Work flow of single rope grab:

• Start from opening the grab bucket and placing it on the material. Due to the gravity, the slip block drops and the convex block is jammed into an Angle of about 30° by the thimble.
• Lift the wire rope, the whole slide block moves up along the guide rail, and after moving a small distance, the convex block connects with the groove (the convex block rotates at a small Angle again), driving the entire lower beam to move up, completing the grab closing and grabbing.
• When unloading, release the wire rope. At this time, the bottom of the grab first contacts the supporting surface. Due to gravity, the sliding block descends and the bump is pushed into a horizontal direction by the thimble (the grab is not opened).
• When the steel wire rope is lifted, the sliding block moves upward, the cam is blocked by the groove to a vertical shape, and is located on both sides of the guide rail, so the sliding seat is separated from the lower bolster and moves upward toward the upper bolster. Due to the weight, the bucket flap opens and discharges.
• After unloading, the grab is in an open state in the air and placed on the material. The slide block drops and the cam is jammed into an Angle of about 30° by the thimble to complete a grabbing process.

Crane grab applications:

• Single-rope grab has a simple working principle and easy to use, disassemble and hang,. Mainly suitable for underwater and land operations, for material grabbing and stacking.
• Single cable grab also widely used in ports, docks, station yards, mines, etc. to load various bulk cargoes, logs, minerals, coal, sand and gravel, earth and stone, etc.

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