Anti-sway techniques for single-beam bridge cranes in engine lifting

1. Equipment inspection and preparation: eliminate mechanical hazards

Transmission system maintenance

Gear coupling and reducer: Check whether the gear and its coupling key are loose, and whether the clearance between the connecting bolt of the transmission shaft and the hole has become too large (the clearance should be ≤0.5mm). If there is any looseness or excessive wear, it is necessary to tighten or replace the components to avoid twisting and swaying of the vehicle body caused by transmission clearance.

Wheels and bearings: Confirm that the wheels rotate flexibly and the bearing seat plate is not skewed. If a certain wheel stops first due to poor clamping, it will cause the vehicle body to tilt, exacerbating the shaking.

Consistency of brakes: The braking torque of the brakes on both sides of the crane, which are driven separately, needs to be consistent (with an error of ≤5%). If one side of the brake wheel has stopped while the other side continues to rotate, it can cause the crane body to sway or even break the drive shaft.

Matching of lifting device and load

Lifting point selection: Determine the designated lifting points according to the engine maintenance manual, and use specialized slings or lifting belts for fixation to avoid load imbalance caused by incorrect lifting points.

Load limit: Confirm that the engine weight is within the rated load capacity of the crane (usually with a 20% safety margin), and strictly prohibit overload lifting.

II. Operational norms: Stably control the movement process

Lifting and lowering control

Slow lifting and lowering: When lifting and placing the engine, control the lifting and lowering speed (recommended to be ≤0.5m/s), and avoid sudden acceleration or braking. During the lifting and lowering of the load, the movement of the crane and trolley is not involved, so the swing angle will not increase. However, it is necessary to prevent impact caused by sudden changes in speed.

Vertical alignment: The lifting hook must be vertically aligned with the center of gravity of the engine, with a deviation angle of ≤3°, to avoid tilting or swinging of the item.

Horizontal movement control

Smooth starting and stopping: When starting a large or small vehicle, avoid sudden acceleration; when stopping, use a deceleration device to prevent load sway caused by sudden stops.

Speed control: Maintain a low speed during driving (it is recommended to be ≤0.3 times the rated speed), especially when turning, as further speed reduction is necessary to avoid increased shaking due to centrifugal force.

Path planning: Plan the lifting path in advance to ensure that there are no obstacles (such as other equipment or buildings) within the operation area, and avoid collisions or getting stuck.

III. Application of anti-sway technology: active suppression of swaying

Mechanical anti-sway

Anti-sway device: Install mechanical shock absorbers or anti-sway rods on the lifting apparatus to reduce load sway through physical damping. It is suitable for high-frequency, short-distance lifting scenarios.

Structural optimization: Modify the crane trolley and lifting structure, such as adopting a dual-rope system or adding a rope guiding device, to reduce the swing amplitude during horizontal movement of the load.

Electrical control anti-sway

Open-loop control: Based on a software model of the load swing process (such as the single pendulum oscillation model), the control algorithm calculates the optimized path. No swing angle measurement device is required, but it is necessary to measure the rope length with the help of a hoisting encoder. The anti-sway control accuracy can reach ±0.5°.

Closed-loop control: Utilizing visual sensors or infrared light sensors to measure the actual swing angle of the load, continuously and smoothly adjusts the walking motion based on advanced control methods such as PID control. The anti-sway control has higher accuracy (±0.2°), and can correct the swing caused by external forces, but requires additional installation of sensors and algorithm modules.