Supply Chain Logistics: Material Handling Equipment

Chapter 3: Material Handling Equipment

Overview

• Explains various types of material handling equipment, from simple hand trucks to complex automated systems.
• Different modes of transportation, facilities, and products require diverse equipment.

Objectives

1. List examples of manual equipment.
2. List types of lift trucks.
3. List types of loading dock equipment.
4. Describe function and types of conveyors.
5. Identify common automated systems used in material handling.

Manual Equipment

• Hand Trucks (Two-Wheel Dolly):
  • Used for moving small items short distances (e.g., storage and parts rooms).
  • Not suitable for large quantities or palletized products.
• Platform Trucks (Picking Carts):
  • Used in confined spaces for picking items to be placed on a conveyor.
  • Requires manual placement of products on the platform.
• Pallet Jacks:
  • Used to move single pallets short distances or in constrained spaces.
  • Can be manual or battery-powered.
  • Hydraulic jack lifts the pallet off the floor.

Industrial Fork Trucks / Lift Trucks

• Many different styles exist for various tasks.
• Powered by electricity, propane, or gasoline.
• Characteristics vary based on load types.
• Electric Trucks:
  • Most widely used due to ease of maintenance, environmental friendliness, and quiet operation.
  • Virtually all stand-up equipment is electric-powered.
• Propane Trucks:
  • More common than gasoline trucks due to better environmental acceptability.
  • Can travel faster and handle heavier loads than electric trucks.
• Gasoline Trucks:
  * Normally used on docks or open areas with more room and ventilation.
  * Effective outdoors and less affected by weather than electric trucks.

Safety Considerations

• Forklift accidents are a leading cause of injuries.
• OSHA reports approximately $85$ deaths per year in the U.S. due to forklifts.
• There are almost $35,000$ accidents that result in serious injury and over $60,000$ that are classified as non-serious.
• Estimated to be more than $850,000$ lift trucks in use in the U.S.
• Different types of powered industrial trucks present different operating hazards.
• Workplace conditions are factors in hazards associated with powered industrial trucks.
• Retail establishments often face greater challenges maintaining pedestrian safety.
• Injuries occur when lift trucks are driven off loading docks, fall between docks and unsecured trailers, or workers fall on elevated pallets.

Types of Lift Trucks

• Stand-up Counterbalanced Lift Truck:
  • Driver stands for better visibility of the load and path.
• Sit-Down Counterbalanced Truck:
  • Most common in warehouses.
  • Can be electric, propane, or gasoline-powered.
  • Typically rated to handle up to $6,000$ pounds.
  • Used in high-volume shipping and receiving.
  • Also referred to as forklifts, fork trucks or lift trucks.
• Order Picker:
  • Lifts the operator with the load to elevated rack locations.
  • Used for putaway, retrieval, and picking items from less than full pallet loads.
• Sideloader:
  • Handles larger-than-pallet-sized loads.
  • Forks are mounted perpendicular to the direction of travel for side loading and straddle load support.
• Electric Pallet Trucks:
  • Single pallet truck: operator walks alongside (approximately $3$ mph).
  • Single-pallet rider and double-pallet rider trucks allow the operator to ride (approximately $7$ mph).
  • Double-pallet rider trucks often used for picking full cases in large warehouses.
• Narrow Aisle:
  • Used in rack areas due to smaller aisle requirements (e.g., $8$-ft aisles instead of $10$-ft aisles).
  • Allows for more goods stored in a smaller area.
  • More expensive with a platform for a standing operator.
  • Small turning radius with straddle and reach capabilities.
• Very Narrow Aisle:
  • Developed for better utilization of cubic space.
  • Wire or rail-guided with a turret truck that rotates $180$ degrees.
  • Rack modules stack pallet loads five or six high (up to $32$ - $35$ feet).
  • Requires very flat floors for precise putaway and retrieval at higher heights.
• Counterbalance:
  • Truck weight balances the load's weight to prevent tipping.

Loading Dock Equipment

• Required for using industrial lift trucks and manual equipment in loading/unloading.
• Scissor Lift or Portable Platform:
  • Portable or stationary device that lifts a platform to the height of the trailer or railcar deck.
• Dock Board/Plate:
  • Bridges the gap between the carrier vehicle deck and warehouse doors.
  • Hydraulic dock plates have capacities up to $30,000$ lbs.
• Yard Ramps:
  • Used in the yard to allow vehicles to drive onto a trailer or container.

Conveyors

• Used to move products over short distances (e.g., loading and unloading areas).
• Gravity Conveyors:
  • Basic and least expensive.
  • Metal bars with wheels or rollers.
  • Positioned at an angle for gravity to roll containers.
  • Can be permanent or portable.
  • Types: gravity wheel, roller, and accordion wheel conveyors.

Specialized Equipment

• Carton Clamp Trucks:
  • Used for moving large, bulky items stored on the floor in bulk locations.
  • Equipped with large rubber-lined clamps (typically $4$ feet x $6$ feet) using hydraulic pressure.
  • Clamp attachment can be mounted on a standard forklift with the appropriate load capacity.
• Attachments:
  • Many lift trucks have switchable attachments like clamps for different items (pallets, barrels, etc.).
• Yard Lift:
  • Truck equipped with pneumatic tires for operation on rough outdoor areas.

Overhead Handling Equipment

• Used to maximize floor space by moving items above the floor.
  • Overhead Traveling Conveyor:
  • Carriers travel on motorized rails above the factory floor.
  • Overhead Crane and Hoist:
  • Used in battery changing or maintenance departments.
  • Overhead Traveling Cranes:
    • Simple design, follows a fixed path.
    • Components: runways, end trucks, bridge beam, and hoist.
      • Runways: Track on which the crane travels.
      • End Trucks: Carriers attaching runways to the warehouse structure.
      • Bridge Beam: Connects end trucks.
      • Hoist: Lifting mechanism (electrically powered chain or wire rope hoist).

Powered Conveyor

• Uses belts, chains, and motors to drive rollers.
• Moves packages horizontally or vertically.

Automated Conveyor Systems

• Moves materials throughout a facility with minimal human involvement.
• Conveyor Sorting Systems:
  • Sort full cases or repack cartons down specific shipping lanes using barcodes.
  • Can sort $10,000$ to $20,000$ or more cases per hour with accuracy.
• Vertical Reciprocating Conveyors (VRCs):
  • Move materials vertically using buckets, fixed arms, or platforms.

Gantry

• Crane with a bridge beam and hoisting mechanism (powered or manual).
• Often has wheels for easy movement around the facility.
• Straddles a load to lift it.
• Not restricted to a fixed path.

Automated Systems

• Automated Guided Vehicle (AGV):
  • Guided by fixed paths (wire, tape, paint, magnets) or lasers.
  • Operates without a person.
• Automated Storage/Retrieval System (AS/RS):
  • Rail-running, robot-like vehicle for storing and retrieving loads.
  • Operates in an aisle between storage rack structures.
  • Can putaway and retrieve loads from racks up to $100$ feet tall or taller.
• Shuttle System:
  • Used to store and retrieve loads in an AS/RS.
  • Multiple shuttles can operate simultaneously.
  • Centralized storage/retrieval machine moves loads to and from shuttles to pickup/deposit stations.
  • High throughput.

Terms to Know

• Automated Guided Vehicle (AGV) System: A transportation network that automatically routes one or more material handling devices, such as carts or pallet trucks, and positions them at predetermined destinations without operator intervention.
• Counterbalance: When the weight of a lift truck offsets the weight of the load it carries.
• Dock Board (Dock Plate): A board or plate used to bridge the gap between a dock and trailer opening that allows people or equipment to move safely from one platform to another.