Material Handling Equipment:Crane and Hoist Overview

Material handling introduction

Material handling can be defined as an integrated system for materials moving, handling, storing, and controlling by means of gravity, manual efforts or power activated machinery.

Material handling is important for more than 80% of time materials or objects or loads spend on a shop floor is spent either in waiting or in transportation. With efficient material handling, time and space will be saved through handling, storage, and controlling of objects.

Material handling principles

According to the study by CIC-MHE and Material handling Institute, the following principles are compiled for material handling:
1. Planning principle: All material handling should be the result of a deliberate plan. The material handling plan should define the material (what), and the moves (when and where), and the handling method (how and who).
2. Standardization principle: Standardize the handling methods and equipment wherever possible.
3. Ergonomic principle: Human capabilities and limitations must be recognized and respected in the design of material handling tasks and equipment to ensure safe and effective operations.
4. Work principle: Material handling work should be minimized or simplified without sacrificing the productivity or the level of service require of the operation.
5. Unit load principle: Unit loads shall be appropriately sized and configured in a way that achieves the material flow and inventory objectives at each stage in the supply chain.
6. Space utilization principle. Effective and efficient use must be made of all available space.
7. System principle: All material handling activities should be integrated to form a coordinated, operational system.
8. Automation principle. Material handling operations should be mechanized and automated whenever is possible to improve efficiency, reducing cost and improving safety, etc.
9. Environmental principle. Application environment and conditions should be taken into consideration when designing or selecting the material handling equipment.
10. Life cycle cost principle. The economic analysis should be conduction on the entire life cycle of all material handling equipment.

Material handling methods

Generally speaking, material handling methods can be grouped into manual material handling, mechanical material handling, and automated material handling.

Manual material handling, mechanical material handling, automated material handling

For different material handling environments and conditions, different material handling methods are adopted. Generally speaking, manual material handling has high flexibility but lower productivity while the automated material handling has high capacity but with lower flexibility, and the mechanized and soft automated material handling comes in between. The relation between flexibility and capacity of different material handling methods are shown in the picture for your reference.

Material handling methods

Besides the flexibility and capacity, the other features of different material handling methods are shown in the following table for your reference:

Charscteristics of different types of material handling methods

Material handling equipment

Generally speaking, the following types of material handling equipment are involved in material handling.

1.  Transporting equipment, for material moving, such as, conveyors, cranes and hoists, and industrial trucks.
2.  Positioning equipment, to handle material at a single location, such as, lift table, dock lever, hoist, and industrial robot, etc.
3. Unit load formation equipment, to handle and maintain material integrity during transporting and storing, such as, pallets, skids, bags, crates, etc.
4. Storage equipment, to holding or buffer materials over a period of time, such as, drive-in rack, sliding rack, etc.
5. Identification and control equipment, to collect and communicate the information that is used to coordinate the flow of materials within a facility and between a facility and its suppliers and customers.

Cranes and hoists

Cranes and hoists are frequently used for material handling. Generally, the loads handled by cranes are more variable in terms of shapes and weights than those handled by a conveyor. Hoists are usually attached to cranes for lifting, lowers and transporting materials or loads.

General characteristic of cranes and hoists:

• Material handling cranes and hoists are used to move loads horizontally and vertically within the covering area of the material handling equipment.
• Material handling cranes and hoists provide more flexibility in movement than conveyors.
•  Material handling cranes and hoists can handle loads with various shapes and can handle loads with heavier weights than those handled by a conveyor.
• Operation methods of cranes and hoists: Suspension panel, driver’s cabin, remoter control, or mixture of the above mentioned operation.
• Cost of floor space: Different type of cranes and hoists occupy different floor space.
• Lifting height: High, can be customized according to requirements.
• Loads capacity: Depends on loads requirement can be customized.
• General application: Moving varying loads within the rated capacity of the cranes and hoists intermittently to any point within a covering area of the cranes and hoists.

Features of materials handled by cranes and hoist:

General types of cranes and hoists:

For material handling, the following types of cranes and hoists are used: Bridge cranes, gantry cranes, jib cranes, and stacker cranes.

Jib crane

Jib crane drawing

Features of jib cranes:

• Supported by or mounted on a stationary vertical pillar.
•  Hoist can move along the jib for moving and lifting loads or objects.
• Performed like an arm and functioned as a manipulator for positioning tasks in the workshop.
• Jib or arm can rotate up to 360°.
• Jib also can be mounted on the wall.

Bridge crane

Bridge crane drawing

Features of bridge cranes

• Bridge crane runs on the bridge supported by the track installed on the wall of the buildings or on the steel structure designed and installed according the crane application environment.
• Bridge cranes can make the 3 dimensional material handling possible at the covering area of the crane.
• Wide selection： Top running bridge crane for heavier loads or objects and underhung bridge crane handling loads or objects with more versatility.

Gantry crane

Features of gantry cranes：

• Semi-gantry crane with single leg, full gantry crane with double legs, and mobile gantry cranes are available for various material handling.
• Similar to a bridge crane except the gantry crane is supported by crane leg or legs instead of walls.
• The supports of gantry crane can be fixed in positon or they can travel on a rail track.
• Gantry cranes can be used indoors and also can be applied in outdoor applications.

Stacker crane

Stacker crane drawing

Features of stacker crane

• Similar to a bridge crane except that stacker crane uses a mast with forks or plat form to handle unit loads instead of a hoist or trolley.
• Stacker crane can be used to store and retrieve unit loads in storage racks, especially in high-rise applications in which the racks are more than 50 feet high.
•  Stacker crane can be controlled by remoter or by an operator in a cab.
• Stack cranes can be considered as a fork trucks on a rail.