Warehouse Overhead Crane

The efficiency and storage capacity of a warehouse mainly depends on the material handling equipment it uses. The material handling equipment enables warehouse workers to efficiently and safely lift, move and store various items and commodities in the warehouse and also position the heavy objects with precision that cannot be achieved in other ways.

The equipment includes overhead cranes, gantry cranes, jib cranes, hoists, etc. Read on to learn about the various types of warehouse cranes in use today.

Overhead Cranes

Overhead crane is also known as bridge crane. As the name suggests, it spans the gap between the two runway tracks in the warehouse.

The warehouse overhead crane can make full use of the space under the bridge to lift materials without being hindered by ground equipment. It is one of the most commonly used cranes in warehouses.

Gantry Cranes

Gantry crane is a variant of bridge crane. Its metal structure is a gantry frame, with two supporting legs installed under the main beam, which can run directly on the track of the ground, and the two ends of the main beam can have extended cantilever beams.

If your warehouse does not have support columns or engineering columns to support the installation of an overhead crane, you can choose a gantry crane.

Jib Cranes

Jib crane is a light duty crane used in warehouse. It is widely employed for high-efficiency automatic production lines, especially suitable for short distances, frequent use and intensive lifting operations.

The jib crane has characteristics of high efficiency, energy saving, labor saving, small footprint, easy operation and maintenance.

Aicrane Warehouse Cranes To Optimize Your Efficiency

If you want to use warehouse cranes to optimize your warehouse efficiency, Aicrane can help you design the right lifting solution to achieve maximum efficiency, safety and cost-effectiveness.

Due to the large number of components of the warehouse overhead crane, we divide the maintenance and inspection cycles into weeks, months, and years in actual work according to the different technical characteristics of each component.

Weekly Inspection And Maintenance

• Check whether the nuts, split pins, and positioning plates on the brake are complete orloose, whether the pin bolts and buffer washers on the brake wheel are loose or complete; whether the brake is reliable in braking. When the brake is opened, the opening of the brake shoe should be less than 1.0mm and the gap between the two sides of the brake wheel should be equal, and each axle pin should not be stuck.
• Check whether the safety protection switch and limit switch are positioned accurately,work flexibly and reliably, especially whether the lifting limit switch is reliable.
• Check whether the wire rope winding on the drum and pulley is normal, whether there is de-grooving, stringing, knotting, twisting, etc., whether the wire rope pressing plate bolts are fastened, and whether there is a double nut anti-loosening device.
• Check whether the fastening screws on the coupling seal cover of the lifting mechanism are loose or lacking.
• Check whether the transmission of each mechanism is normal and whether there is abnormal noise.
• Check whether the lubrication condition of all lubrication parts is good.
• Check whether there are any foreign objects on the track that hinder the operation of the overhead crane.

Monthly Inspection And Maintenance

• Check that the wear of the brake pad liner should not exceed 2mm, and the contact area between the liner and the brake wheel should not be less than 70%; check the installation and fixation of each pin, wear and lubrication, and the wear of each pin should not exceed 5% of the original diameter, the wear of the small shaft and the mandrel should not be more than 5% of the original diameter and the ellipticity should be less than 0.5mm.
• Check the wear and tear of the wire rope, whether there are broken wires, and check the lubrication condition of the wire rope.
• Check whether there are cracks in the hook, whether the wear of the dangerous section exceeds 5% of the original thickness; whether the anti-loosening device of the hook nut is complete, and whether the various parts on the hook group are complete and reliable.The hook should rotate flexibly without jamming.
• Check all bolts for looseness and shortage.
• Check the tightening of the bolts of the motor, reducer and other bases, and tighten them one by one.
• Check the lubrication condition of the reducer, the oil level should be within the specified range, and measures should be taken to prevent leakage at the oil seepage part.
• Lubricate the gears.
• Check the wear of the wire rope at the balance pulley, and lubricate the pulley and pulley shaft.
• Check the condition of the pulley to see if it is flexible, whether it is damaged or cracked, and pay special attention to the wear of the fixed pulley shaft.
• Check the brake wheel, the unevenness of the working surface should not exceed 1.5mm, the brake wheel should not have cracks, and its radial runout should be less than 0.3mm.
• Check the coupling, its upper key and keyway should not be damaged or loose; the axial series momentum of the drive shaft between the two couplings should be 2~7mm.
• Check the operating conditions of the warehouse crane and trolleymechanisms and there should be no phenomena such as rail gnawing, three fulcrums, and twisting when starting and stopping. Check the wear of the rim and tread of the wheel. The wear of the rim thickness should not exceed 50% of the original thickness, and the wear of the wheel tread should not exceed 3% of the original diameter of the wheel.
• Check the track condition of the warehouse crane to see if its bolts are loose or lacking, whether the pressure plate is fixed on the track, whether the track is cracked or broken; whether the gap between the two track joints is 1~2mm (summer) or 3~5mm (Winter), whether the joint up and down, left and right misalignment exceeds 1mm.
• Clean the overhead crane comprehensively and remove the dirt on it.

Semi-annual Inspection And Maintenance

• Check the gear meshing and wear of all reducers. The pitting damage of the tooth surface should not exceed 30% of the meshing surface, and the depth should not exceed 10% of the original tooth thickness (fixed string tooth thickness); the percentage of gear tooth thickness wear to the original tooth thickness should not exceed 15%~25%; check the condition of the bearing; replace the lubricating oil.
• Check the condition of the crane and trolley wheels, lubricate the wheel bearings, and eliminate the phenomenon of rail gnawing.
• Check whether the main welding seams of the main beam and end beams are open or corroded. The corrosion should not exceed 10% of the original plate thickness. Whether there are fatigue cracks in the main stressed parts; whether the various guardrails and supports are intact; check the main beam and end beam bolts and tighten them again.
• Check the deformation of the main beam, and the condition of the trolley track. Disturbance of the main girder should not exceed 1/2000 of its span when there is no load; the inward horizontal side bending of the main girder should not exceed 1/1500 of the measured length; the track of the trolley should not be jammed,and the wear on the top and side of the track (single side) should not exceed 3mm.
• Check the condition of the drum, the wall of the drum should not be worn more than 20% of the original wall thickness, and the peak of the rope groove should not be sharp.
• Tighten all connecting bolts and fastening bolts on the crane.

The safety devices are mainly to prevent various hazards during the operation of the crane. The types of safety devices provided in a warehouse overhead crane include:

• Overload limiter
• Torque limiter
• Buffer
• Limit position limiter
• Interlock protection
• Zero protection
• Emergency switch
• Sweeping rail plate, support frame and rail end stop
• Conductive sliding wire protection board

The principle parts of an overhead travelling crane include: bridge frame, lifting mechanism, trolley running mechanism, crane running mechanism, cabin and electric control system

Bridge frame – it is the basic component of the overhead crane, which is mainly composed of main beam, end beam, walking platform, etc. Both ends of the main beam are connected with the end beams, and a rail track is laid above the main beam for the trolley to move.

Lifting mechanism – it is composed of lifting motor, reducer, drum, and brake. The hoisting motor is connected to the reducer through the coupling and the brake wheel. The output shaft of the reducer is connected to the drum of the wire rope. The other end of the wire rope is attached with a hook. When the drum rotates, the hook is wound with the wire rope to raise or lower the load. For warehouse overhead cranes with a lifting capacity of 15t and above, there are two sets of lifting mechanisms, namely the main hook and the auxiliary hook.

Trolley running mechanism – trolley is mounted on the rail of the bridge frame, and moves along the bridge girder. The trolley running mechanism is composed of the trolley motor, brake, coupling, reducer and wheels. The motor of the trolley drives the driving wheels through the reducer to drive the trolley to move along the guide rails. Since the driving wheels of the trolley are close together, they are driven by an electric motor. There are two transmission modes of the trolley runnning mechanism: one is that the gearbox is between the two driving wheels; the other is that the gearbox is installed on one side of the trolley. The former makes the torque borne by the drive shaft more uniform, and the latter makes installation and maintenance more convenient.

Crane running mechanism – it is composed of motor, transmission shaft, reducer, wheel, brake, etc. The driving mode includes centralized driving and separate driving.

Cabin – in the control room, there are control devices for the lifting mechanism, trolley running mechanism and crane running mechanism, and protection devices for cranes. The control room is generally fixed at one end of the main beam.

Electric control system – the standard power supply of our warehouse overhead cranes is three-phase AC, with a rated voltage of 380V and a rated frequency of 50Hz. It can also be designed according to user requirements.