Instructions of Mini Industrial-Cranes

 1. Function Parameter of Mini Industrial-cranes

1.1. Rated lifting weight
It refers to the maximum lifting weight of the crane under safe working conditions. The weight decreased with the increase of working extent.

1.2. Working radius (working extent)


The distance from the rotative central axis to the center of the hook is always measured with loads. The working extent with loads is about 0.5m-2m greater than the unloaded state because the components are out of shape when lifting. (see attached Figure 1)

1.3. Lifting Height
The distance from the surface of the landing legs to the center of the hook mouth is the lifting height. The rated lifting height refers to the maximum lifting height with full load.

1.4. Load Moment
The product of the lifting capacity and its corresponding working radius is called the load moment which compose the overall index of measuring the traveling mechanism of the crane.

2. Safety regulations of operating industrial-cranes

2.1. It is forbidden to operate the cranes before stretching the landing legs fully, leveling the frames and ground.

2.2. There must be one specially-assigned person to conduct when the crane is ready to work.

2.3. Pull the rope when lifting, and keep the lifting speed stable. It’s not allowed to brake or divert abruptly. It should be 0.5m higher than the obstacle when lifting horizontally. Put down the loads gently in low speed in case of dumping.

2.4. No one remains or walks under the lifting beam when the crane works, and keeps the beam and loads at a safe distance from the aerial cables.

2.5. It’s prohibited to stand or operate on the loads when lifting. Brake the lifting arm, hook and the rotative detent, and put down the loads before operation. The operating personnel and commanders must stick to their post.

2.6. Free-fall lifting is strictly forbidden, and heavy objects should be put down with a low speed.

2.7. The crane must lifts things in a vertical direction. It is not allowed to pull weights that still on the ground to avoid side-loading.

2.8. It is forbidden to use two or more operating actions with full or near full lifting capacity. The angle of the left-right rotating should less than 45°. It is prohibited to lift in a slant, tensile way or a rapid elevating. Don’t poke, bury loads under the ground and pull the large objects that stick to the ground.

2.9. Keep safety distance when the crane works with or around energized electrical circuits or equipments. Lay down the lifting beam when the crane passes the electric transmission line.

2.10. Overloading operation is prohibited. If two cranes are working together to lift one heavy load, there must be unified commanded by one specially-assigned person; Make sure the two cranes are in the same speed, and the load is less than 75% of the total lifting weight of the two cranes. Pay attention to the allocation of the load, and the allocation should be less than 80% of the rated lifting capacity of each crane.

2.11. There must be a certain distance between the hook and the lifting arm in case that the winch exceeds the limits which maybe lead to the wire ropes break or the lifting arms turn backwards. There must be three or more turns on the winch roller when the hook at its lowest level and the lifting arm stretch to its maximum elevation angle.

2.12. Under working condition, the elevation angle should be more than 30°, and you should refrain the lifting arm with an load from changing. Don’t shift the action bars until the lifting stops.

2.13. No repairmen or modulation under working conditions.

2.14. Take a break or lockout after unloading completely.

2.15. After finishing the work, you should put back the hook and lifting arm in place, and set back all the control handles.

2.16. Don’t pull back the landing legs and revolving arms at the same time. You should keep the arm extension flat, hang the load hook over the pothook, and tighten the wire rope.

3. Tips for the conductors and operation staffs

3.1. The conductors must explain the job clearly to the staffs. If the operation personnel can’t see the command signals, there will be a transmitter to help them.

3.2. The gestures should be clear, signals should be explicit. Don’t use gloves during the conduct.

3.3 Check out the binding situation before lifting loads; be sure that Pads is used at the edges, corners, and cuts where the ropes pass by; there are no wrap, lower or sidelong phenomenon under the stress of weight, and the center of gravity of lifting keeps precisely.

3.4. The operation staff can’t leave his working post without getting a replacement before fixing the suspended loads. Don’t stop working with the rigging is stressing or the loads still hangs in the air.

3.5. The conductor should take actions to reduce the overload when the operation staffs refuse to lifting with overweight. No privilege in overload operation.

4. Operative skills and bans of hoisting

4.1. Skills and bans of landing legs
●Drive the crane to the right place (stop within the operation scope as shown in the Figure 2; the block is the load), and adjust the distance according to the space size or the bulk of the weight. Outstretch the legs to make sure the third section of the leg stretches fully and the second part extends to its limit (P.S. the lifting parameter table is the maximum angle when the landing legs expand). Insert the bolt when complete the adjustment, then set up the landing leg as the Figure 3. If the ground is soft or uneven, you must level it up tightly with skids or steel plates for the landing legs.





●Level the bodywork of the crane when the leg off the ground (crawler belt is about 50mm higher off the floor) by the reference of the gradienter.

4.2. Skills and bans of amplitude of variation

●When the amplitude of variation undergoes changes, the lifting arm is not allowed to surpass the limit angle. Take notice that the lifting only works perpendicularly.

● Pull operating handle slowly when you start or stop to change the amplitude of variation.

●It will bend downwards when the lifting arm hoists the load off the ground, which will increase the amplitude of variation, or lead to overload. Considering such a situation, the users should left spare capacity in advance.

●You should notice that the rated lifting weight decreases as the working radius increases when the lifting arm draws back. On the contrary, the rated lifting weight increases when the working radius decreases. Therefore you should operate the crane according to the lifting parameters (Figure 4).
 4.3. Skills and bans of stretching out/ drawing back the lifting arm

●The crane will turn over if you stretch out/ draw back the lifting arm out of the limit of the lifting parameters.

●It is prohibited to stretch out/ draw back the lifting arm with loads, except the instruction book says yes.

●The length of the wire rope changes frequently because it in a forceful working condition invariably. So the users should examine and adjust the flexibility of the lifting arm per month. Regulate the rating nut if it can’t stretch out/ draw back at the same time or chattering phenomena occurs during the examination.

4.4. Skills and bans of rotative operation

● Check out the lateral span of the landing leg to assure that the space is enough for the rorative operation

●Pull operating handle in a low speed when you start or stop the rotative operation.

●Don ‘t drag the loads that still stick to the ground when lifting.

●We should keep the rotatvie operation in a relative stable state and slow speed to reduce the swings to the greatest extent.

 4.5. Skills and bans of hoisting mechanism (winch)

●Lift loads slightly higher than the floor before lifting high in the air, especially when the loads are closely reach the rated weight, so that you can verify the working radius and actual weight of the load are within the limits with observing the weight limiter and the load limit device. Then you can go on the lifting operation.

●The wire ropes should be more than three turns on the roller when the hook lower to the ground or the bearing surface of the crane.

●Don’t drag the loads that still stick to the ground when lifting; the crane only works perpendicularly in any case.

●We should lay down the wire rope when stretching the lifting arm without load to avoid the hook crashes into the lifting arm. Take the wire rope back when drawing back the arm for fear that the wire ropes twist together.

●Dismantle the lock catch and rotate the ropes reversely to untangle the knots if it does happen.