The automation of vehicles is usually tied to improved safety, whether it is on the road or in a warehouse, compartment floor, or load center. The automation of industrial trucks could be the future of efficient material flows. This is because driverless industrial trucks can take over tiring transport tasks from employees, increase the handling volume, and reduce the error and accident rates in the warehouse. ISO 3691-4:2023—Industrial Trucks – Safety Requirements And Verification – Part 4: Driverless Industrial Trucks And Their Systems provides safety requirements for driverless industrial trucks and their systems.
What Are Industrial Trucks?
An industrial truck is a carrier designed to transport materials within a factory area with maximum flexibility in making moves. It permits mechanized pickup and deposit of the loads, eliminating manual work in lifting as well as transporting. Depending on their means of locomotion, industrial trucks may be classified as hand trucks or power trucks.
A hand truck, also known as a hand trolley, dolly, stack truck, trundler, box cart, sack barrow, cart, sack truck, two wheeler, or bag barrow, is an L-shaped box-moving handcart with handles at one end, wheels at the base, with a small ledge to set objects on, flat against the floor when the hand-truck is upright. Hand trucks with two wheels permit most of the load to be carried on the wheels, but some of the load must be assumed by the operator to balance the truck during movement. Four-wheel hand trucks are found in many more varieties, including dollies, high- and low-bed flat trucks, carts, rack carriers, wagons, and various hand-lift trucks having mechanical or hydraulic lifting mechanisms for raising and lowering a load.
On the other hand, powered industrial trucks are propelled by batteries and an electric-motor drive or by an internal-combustion engine with either a mechanical drive or a generator and electric-motor drive. Powered industrial trucks, commonly called forklifts or lift trucks, are used in many industries, primarily to move materials. They can be used to move, raise, lower, or remove large objects or a number of smaller objects on pallets or in boxes, crates, or other containers.
What Is ISO 3691-4?
ISO 3691-4:2023 specifies safety requirements for driverless industrial trucks and their systems. A driverless industrial truck is a powered truck designed to operate automatically; a driverless truck system comprises the control system, which can be part of the truck and/or separate from it. Examples of driverless industrial trucks (trucks as defined in ISO 5053-1:2020) include: “automated guided vehicle,” “autonomous mobile robot,” “bots,” “automated guided cart,” “tunnel tugger,” “under cart,” etc. ISO 3691-4:2023 is also applicable to driverless industrial trucks that are provided with:
- Automatic modes which either require operators’ action(s) to initiate or enable such automatic operations
- The capability to transport one or more riders
- Additional manual modes which allow operators to operate the truck manually
- A maintenance mode which allows manual operation of truck functions for maintenance reasons.
This standard is not applicable to trucks solely guided by mechanical means (rails, guides, etc.) or to remotely-controlled trucks, which are not considered to be driverless trucks. Additionally, it does not cover requirements for power sources.
How Do Driverless Industrial Trucks Operate?
ISO 3691-4:2023 details critical operational requirements for driverless industrial trucks:
Braking Systems
The truck should be equipped with a braking system designed to operate on the interruption of the power supply and activate automatically at the loss of control of speed or steering. Additionally, the braking systems should be able to stop the truck within the operating range of the personnel detection specified by the manufacturer (e.g. speed, friction, floor/ground, gradient, rated load).
Speed Control
To detect overspeed, ISO 3691-4:2023 maintains a stop should be initiated when the truck speed exceeds the rated speed specified by the manufacturer. Speed should also be monitored to ensure stability according to all operating conditions and during all load-handling and travelling movements, including during an emergency or protective stop.
Automatic Battery Charging
Automatic charging connections rated above 60 VDC or 25 VAC should be designed to prevent shock hazards arising from accidental contact with live parts in accordance with IEC 61558-1:2017. A truck equipped with an automatic charging system is designed such that the reachable charging contacts are only activated when the truck is connected to the charging device.
Load Handling
The load-carrying device shall be so designed that the load stays within the limits of position(s) determined by the manufacturer in any operational mode, including during an emergency or protective stop, and load transfer. This can be achieved by integrating clamps, mechanical locks, stops, etc.
Protective devices and complementary measures
Trucks should be provided with an emergency stop function that conforms to ISO 13850:2015.
ISO 3691-4:2023—Industrial Trucks – Safety Requirements And Verification – Part 4: Driverless Industrial Trucks And Their Systems is available on the ANSI Webstore.
