Design specifications for forklift trucks
1 Scope
This document establishes the general, structural, mechanical, electrical, hydraulic and safety design principles of forklift trucks, and specifies the design, calculation requirements and methods.
This document is applicable to counterbalance lift trucks, reach trucks, side-loading trucks, straddle truck, pallet-stacking trucks and lateral-and front-stacking trucks as defined in GB/T 6104.1, and may serve as a reference for other types of forklift trucks.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 985.1 Recommended joint preparation for gas welding, manual metal arc welding, gas-shield arc welding and beam welding
GB/T 985.2 Recommended joint preparation for submerged arc welding
GB/T 2982 Designation, dimensions, inflation pressure and load capacity of pneumatic tyres for industrial vehicles
GB/T 3098.1 Mechanical properties of fasteners - Bolts, screws and studs
GB/T 3766 Hydraulic fluid power - General rules and safety requirements for systems and their components
GB/T 4208-2017 Degrees of protection provided by enclosure (IP code)
GB/T 4662 Rolling bearings - Static load ratings
GB/T 4942-2021 Degrees of protection provided by the integral design of rotating electrical machines (IP code) - Classification
GB/T 5008.1 Lead-acid starter batteries - Part 1: Technical conditions and methods of test
GB/T 5143 Industrial trucks - Overhead guards - Specification and testing
GB/T 5182 Fork-lift trucks - Fork arms - Technical characteristics and testing
GB/T 5184 Fork-lift trucks - Hook-on type fork arms and fork arm carriages - Mounting dimensions
GB/T 6074 Leaf chains, clevises and sheaves - Dimensions, measuring forces and tensile strengths
GB/T 6104.1 Industrial trucks - Terminology and classification - Part 1: Types of industrial trucks
GB/T 7403.1 Lead-acid traction batteries - Part 1: Technical conditions
GB/T 10823 Size designation, dimensions and load capacity of solid tyres for pneumatic tyres rims
GB/T 10827.1 Industrial trucks - Safety requirements and verification - Part 1: Self-propelled industrial trucks, other than driverless trucks, variable-reach trucks and burden-carrier trucks
GB/T 10827.3 Industrial trucks - Safety requirements and verification - Part 3: Additional requirements for trucks with elevating operator position and trucks specifically designed to travel with elevated loads
GB/T 14687 Industrial castors and wheels
GB/T 16622 Size designation, dimensions and load capacity for pressed-on solid tyres
GB/T 17300 Earth-moving machinery - Access systems
GB/T 18849 Powered industrial trucks - Brake performance and component strength
GB/T 26560 Powered industrial trucks - Safety signs and hazard pictorials - General principles
GB/T 26948.1 Industrial trucks - Specifications and test methods for operator restraint systems - Part 1: Lap-type seat belts
GB/T 26949.2 Industrial trucks - Verification of stability - Part 2: Counterbalanced trucks with mast
GB/T 26949.3 Industrial trucks - Verification of stability - Part 3: Reach and straddle trucks
GB/T 26949.4 Industrial trucks - Verification of stability - Part 4: Pallet stackers, double stackers and order-picking trucks with operator position elevating up to and including 1,200mm lift height
GB/T 26949.5 Industrial trucks - Verification of stability - Part 5: Single-side-loading trucks
GB/T 26949.22 Industrial trucks - Verification of stability - Part 22: Lateral-and front-stacking trucks with and without elevating operator position
GB/T 27544 Industrial trucks - Electrical requirements
GB/T 27544-2011 Industrial trucks - Electrical requirements
GB/T 31465.1 Road vehicles - Fuse-link - Part 1: Definitions and general test requirements
GB/T 31465.2 Road vehicles - Fuse-link - Part 2: User's guide
GB/T 41134.1 Fuel cell power systems for industrial electric trucks - Part 1: Safety
3 Terms, definitions, symbols and codes
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 6104.1 and GB/T 10827.1 apply.
3.2 Symbols and codes
The main symbols and codes used in this document, together with their units and meanings, are in accordance with Annex A.
4 Overall design
4.1 Basic composition
Forklift truck is mainly composed of working device, power device and wheeled chassis. The main components of each part are as follows.
a) Working device: mast, fork arm carrier, fork arm and lifting operating platform.
b) Power device:
1) diesel forklift truck: engine, cooling system, fuel system, intake system and exhaust system;
2) electric forklift truck: battery, motor and electrical control elements.
c) Wheeled chassis.
1) Transmission system:
——mechanical transmission of diesel forklift truck: clutch, gearbox and drive axle;
——mechanical transmission of electric forklift truck: gearbox and drive axle;
——hydraulic transmission: hydraulic torque converter, gearbox and drive axle;
——hydrostatic transmission: hydraulic pump, hydraulic motor, gearbox and drive axle.
2) Steering system: steering wheel (tiller), steering gear, steering device and steering axle.
3) Braking system: service braking device and parking braking device.
4) Truck body system: frame, counterweight, hood, bottom plate, seats, overhead guard (cab) and wheels.
5) Control system: throttle (accelerator) control system, brake control system, variable speed control system, steering control system and valve control system.
6) Electrical system: power supply, electrical control elements, auxiliary electrical equipment, wires and cables.
7) Hydraulic system: hydraulic oil tank, hydraulic pump, hydraulic valve, hydraulic cylinder, hydraulic motor, hydraulic pipeline and auxiliary hydraulic elements.
Contents
1 Scope
2 Normative references
3 Terms, definitions, symbols and codes
3.1 Terms and definitions
3.2 Symbols and codes
4 Overall design
4.1 Basic composition
4.2 Load and load combination
4.2.1 General
4.2.2 Calculated load
4.2.3 Load combination
4.3 Dead weight, mass center and axle load
4.3.1 Calculation of dead weight and mass center position
4.3.2 Measurement of mass center position
4.3.3 Axle load
4.4 Maneuverability
4.4.1 Minimum outside turning radius
4.4.2 Minimum right-angle stacking channel width
4.5 Dynamic characteristics
4.5.1 Type selection of engine
4.5.2 Type selection of motor
4.5.3 Type selection of controller design
4.5.4 Overall gear ratio of transmission system for diesel forklift truck
4.5.5 Distribution principle for gear ratio of transmission system
4.6 Tractive characteristics
4.6.1 Tractive force and speed
4.6.2 Maximum tractive force
4.6.3 Climbing ability
4.7 Braking performance
4.7.1 Service braking torque
4.7.2 Parking braking torque
4.8 Stability of complete equipment
5 Structure
5.1 General rules for calculation of metal structural part
5.2 Connection calculation of metal structural parts
5.2.1 Welding
5.2.2 Bolt connection
5.2.3 Pin connection
5.3 Calculation of mast structure
5.3.1 Strength estimation of mast structure
5.3.2 Strength checking of mast structure
5.3.3 Local bending stress analysis of mast
5.3.4 Composite stress of mast
5.3.5 Contact stress analysis of mast roller
5.4 Checking of fork arm carrier structure
5.5 Checking of frame structure
5.5.1 General rules for structure checking
5.5.2 Checking method for structure
6 Machinery
6.1 Lifting system
6.1.1 Basic dimensions of mast
6.1.2 Checking of parts and components
6.2 Steering system
6.2.1 Steering resisting moment
6.2.2 Thrust of hydraulic cylinder
6.2.3 Steering mechanism
6.2.4 Steering axle body
6.3 Drive system
6.3.1 Clutch
6.3.2 Torque converter
6.3.3 Transmission
6.3.4 Coupling
6.3.5 Drive axle
6.4 Braking system
6.5 Wheel
7 Electrical equipment
7.1 Basic requirements
7.2 Power and power supply
7.2.1 Power supply
7.2.2 Control power supply
7.2.3 Power supply system
7.3 Electrical control system
7.3.1 Electrical control elements
7.3.2 Controller
7.3.3 Control system design
7.4 Motor
7.5 Auxiliary electrical equipment
7.5.1 Instruments
7.5.2 Lighting and signaling device
7.6 Communication
7.7 Wires and cables
7.7.1 General requirements
7.7.2 Wire laying
8 Hydraulic
8.1 Basic requirements
8.2 Hydraulic system circuit
8.2.1 General requirements
8.2.2 Hydraulic pump circuit
8.2.3 Load circuit
8.2.4 Unloading circuit
8.2.5 Voltage regulation circuit
8.2.6 Speed limiting circuit
8.3 Type of hydraulic system
8.3.1 Open and closed hydraulic systems
8.3.2 Single-pump, double-pump and split-pump hydraulic systems
8.4 Pressure of hydraulic system
8.5 Design and type selection of hydraulic elements
8.5.1 General principles for design
8.5.2 Hydraulic cylinder
8.5.3 Hydraulic pump
8.5.4 Hydraulic valve
8.6 Auxiliary hydraulic elements
8.6.1 Pipeline
8.6.2 Hydraulic oil tank
8.6.3 Oil filter
8.6.4 Cooler
8.6.5 Energy accumulator
9 Safety
9.1 Basic requirements
9.2 Power system
9.3 Transmission system
9.4 Steering system
9.5 Braking system
9.6 Hydraulic system
9.7 Electrical system
9.8 Control device
9.9 Working device
9.10 Safety protection device
9.11 Safety dimensions
Annex A (Normative) Symbols and codes used in this document
Annex B (Normative) Stability computation
B.1 General rules
B.2 Stability calculation
B.2.1 Counterbalance lift truck
B.2.2 Side‑loading truck
B.2.3 Reach truck and straddle truck
B.2.4 Pallet-stacking truck
B.2.5 Lateral-and front-stacking truck
Annex C (Informative) Characteristics of hydraulic torque converter
C.1 Construction of hydraulic torque converter
C.2 Characteristics of hydraulic torque converter
C.2.1 External characteristics of hydraulic torque converter
C.2.2 Input characteristics of hydraulic torque converter
C.3 Matching of hydraulic torque converter and engine
Bibliography
Figure 1 Schematic diagram for measurement of mass center position
Figure 2 Schematic diagram for steering of front-drive four-wheel forklift truck and single-motor front-drive three-wheel forklift truck
Figure 3 Schematic diagram for steering of double-motor front-drive three-wheel forklift truck and rear-drive three-wheel forklift truck
Figure 4 Schematic diagram for right-angle stacking of front-drive four-wheel forklift truck and single-motor front-drive three-wheel forklift truck when b12/2≤b13
Figure 5 Schematic diagram for right-angle stacking of front-drive four-wheel forklift truck and single-motor front-drive three-wheel forklift truck when b12/2>b13 and b12/2+b13
