In all kinds of loading and unloading operations, heavy and complex environmental material handling tasks often require a lot of manpower and time and are also accompanied by a high safety risk. How can the situation be changed?
To solve a major problem, a "remote control grab" appeared. With the remote control grab's excellent remote control performance, strong grabbing ability, reliable manufacturing process, and other advantages, more and more shipyards and factories are adopting it. So, how does the remote control grab work? To know how an RC grab works, we must first understand its structure.
The grapple mainly consists of
1. Upper bearing beam,
2. Middle bearing beam,
3. Lower bearing beam,
4. Spreader,
5. Bucket body,
6. Control valve group,
7. Oil cylinder,
8. Wire rope group and other major components, see the figure on the right.
How are the parts of a grapple connected?
1. The strut is connected to the upper beam and bucket body by the pin, and the bucket body is connected to the lower beam by the pin;
2. The lower bearing beam is connected to the cylinder barrel, the middle bearing beam is connected to the cylinder piston rod and the two cylinders are symmetrically distributed;
3. The wire rope group lifts the middle beam, the wire rope is symmetrically distributed and increases the closing force of the grab through the upper beam and the pulley winding group on the middle beam;
4. The balance frame on the middle beam supports the lifting weight of the grab, and the two ropes are balanced with each other to avoid excessive force on a single rope;
5. The lower beam is of a box-type structure, the centre is designed as a fully enclosed oil tank, and the oil tank cover is equipped with a control valve group.
Opening and closing of the grab
Grapple closing:
When the grapple is opened, the centre beam is in contact with the upper beam and completely separated from the lower beam. At this point, the electromagnetic reversing valve is closed because the cylinder piston rod is fixed to the centre beam and the cylinder barrel is fixed to the lower beam, so the cylinder piston rod is fully extended at this point.
When the load is to be grabbed, the crane sling is lowered and since the cylinder piston can be guided unidirectionally, the cylinder piston rod can be retracted and the centre bearing beam lowered accordingly.
When the cylinder piston rod is fully retracted, the centre support beam is also fully lowered. As the solenoid valve of the oil cylinder is always closed, at this time the rod chamber of the oil cylinder is locked, the oil cylinder is in the closed locking state, under the action of the pulley group, the centre support beam rises to drive the lower support beam gradually upwards and to drive the jaws to close.
Grapple opening:
when it is necessary to open the grapple, simply press the button on the remote control transmitter, open the electromagnetic reversing valve of the oil cylinder and relieve the rod chamber of the oil cylinder. The piston rod of the cylinder is pulled out by the action of the middle and lower support beams, separating the middle and lower support beams and opening the grapple.
