Look at almost any advance in distribution center performance and you'll find that lift trucks are integral to it.
Over the years, lift truck technology has enabled space-saving concepts like narrow aisles and taller racks. Truck enhancements – faster speeds, greater capacities, higher reach, increased-efficiency drive systems, control automation, and ergonomic designs – have helped operators work more efficiently and have progressively reduced per case handling cost.
Intelligent truck designs have even helped simplify interaction between operators, pallet loads, and the warehouse management systems that handle the flow of information on which modern distribution centers depend.
What comes next? In view of how far lift trucks have come in the past 50 years, some may be tempted to think like Charles Duell, former head of the U.S. Patent Office, who argued in 1899 that his office should be closed because "everything that could have been invented, has been invented."
In reality, lift truck technology continues to move ahead, and not just in small, incremental steps. In fact, recent innovations like AC drive, and innovations on the near-term horizon – notably fuel cell technology and radio frequency identification (RFID) – will enable new leaps forward in lift trucks and their roles in warehousing productivity.
While distribution centers have changed greatly in the past half-century, their owners' basic objectives have not. Speed, efficiency and accuracy continue to drive customer satisfaction and business success. With product purchase and selling prices essentially locked in under the realities of the marketplace, profit margin depends more than ever on driving down operating costs within the distribution chain. Lift trucks and their operators are central to such efforts.
The path toward today's lift truck designs began in the mid-1940s with the invention of the four-way pallet, which became the industry standard and dramatically changed how shippers and receivers handled loads. Good lift truck design became a question of creating vehicles to interact in more and better ways with these pallets.
As distribution centers sought to optimize use of floor space, the most obvious step was to build taller racks. Traditional counterbalance forklifts, which carry loads outside the vehicle structure, become more unstable when operating at higher heights. The higher the lift, the more counterbalancing required, and so the bigger the truck. Larger forklifts of course demand wider aisles, negating some of the benefits of storing product higher
The first major lift truck innovation was the straddle truck. Designed without a counterbalancing chassis, it handled pallets within the vehicle envelope and so could lift loads higher while retaining stability. This innovation allowed the trucks to be smaller, reducing aisle width requirements. The first straddle trucks, introduced in 1951, enabled aisles as narrow as 72 inches (versus the previous standard of 120 to 144 inches) and started the narrow-aisle revolution.
Stream of innovations
The straddle truck started a series of dramatic lift truck innovations. As the demand for narrow-aisle vehicles increased, manufacturers responded with more compact, higher-reaching trucks, including designs for specialized applications. Major milestones included:
Reach-Fork trucks. Introduced in 1954, these trucks overcame some limitations of straddle trucks and overtook the straddle truck as the truck of choice. Reach trucks easily handled pallets of variable widths and enabled more narrowing of aisles. They remain today the workhorses of the warehousing industry.
Side-loading trucks. These trucks fit special applications where long, bulky materials must traverse narrow aisles. They offer multidirectional travel with heavy-duty capacities and stacking capability – from 2,000 to 10,000 pounds up to 30 feet high.
Guided order pickers. Operators on these units rise with the load to pick items from racks. Wire or rail guidance frees operators from steering in narrow aisles, enables higher travel speeds while elevating to the next location, and speeds aisle transfers. Variable controls let operators feather the lifting and lowering speed for exact platform placement.
Deep reach trucks. Created to maximize cube utilization, these units are designed to reach into racks to access loads. Designed for high-density storage systems that require multiple slots for single SKUs, they can save two aisles out of every five when compared to single-deep storage.
Very Narrow Aisle (VNA) turret trucks. Released in 1974, these operator-up trucks have the ability to rotate loads up to 180 degrees to service both sides of an aisle. They can handle full pallets and case picking in aisles as narrow as 66 inches.
Starting in the 1970s, warehouses began to grow rapidly in sophistication. SKUs proliferated, distributors adopted just-in-time techniques, and demand increased for equipment to enable taller racks with narrower aisles.
The very narrow aisle concept was slow to catch on because the early VNA trucks were relatively expensive. That changed in the 1990s with the introduction of much more affordable VNA trucks with similar load capacity at height, yet superior ergonomics and productivity.
For handling long loads, four-directional trucks were developed, with the ability to travel forward, back, and side to side. These units move lumber, furniture, pipe, rolled steel, and similar loads weighing up to 4,500 lbs. in narrow aisles. They enable users to create narrower aisles with denser storage, increasing storage space up to 40 percent.
The impact of truck innovations on storage heights was profound. In the early 1960s, rack elevations of 300 inches were regarded as high. By the early 1970s, rack heights had risen to 350 inches; by the 1990s they had reached 400 inches. Today, 500-inch-tall racks are not uncommon, and lift trucks handle standard 48-inch pallets in aisles as narrow as 58 inches.
Meanwhile, aided by an explosion in microprocessor power, manufacturers turned to innovations that would help owners get more performance and productivity from their lift truck designs.
Arguably the most powerful innovation was AC drive technology. AC motors are more energy-efficient than DC motors, operating longer between battery charges. AC powered trucks also experience less reduction in truck performance as the battery discharges. Operators benefit from improved acceleration and smoother, more precise control.
The AC systems require less maintenance: AC controllers have no wearable parts, and because the motors have no brushes, there is no brush replacement and no residual carbon to clean from the compartment. Cooler-running AC motors also limit the wear and tear that results from heating of truck components.
Overall, operators using AC trucks commonly experience double-digit improvement in energy efficiency, increased truck uptime (truck utilization) due to fewer battery changes, and significant maintenance cost reductions.
Other significant improvements came from electronic systems that enhance vehicle control and performance and operator comfort. Here, the goal is to enable operators to focus more energy on moving pallets and picking orders, and less on actually manipulating the truck. Among these innovations are:
Intelligent speed control. This feature electronically selects the optimum maximum travel speed at every elevation based on the height of the forks, weight of the load, heading angle, travel direction, load handler position, status of guidance, and operator speed request. The net result is travel speeds at elevation that are up to 30 percent higher between picks. This means more picks per hour with less operator stress.
Automatic steering centering. Created for orderpickers, this digital system centers the drive tire at start-up, improving operator productivity and reducing truck and rack damage.
Coast control. This capability for low-lift pallet trucks also increases picks per hour. With coast control, the operator can coast the truck between nearby pick locations, using a jog button or twist grips to move the truck from slot to slot. The coast control automatically disengages when the operator boards the truck and pushes the accelerator button to reach top speed. The system saves precious seconds each time operators engage and disengage coast to perform floor-level order picking. This can translate into a few more minutes of productive order picking time per operator per hour.
Advanced ergonomic control. This system is designed to optimize the interaction between operator and machine. It starts with an intelligent drive system that sharply reduces the number of mechanical and electromechanical components in the truck. The system continuously optimizes the vehicle’s total performance and provides real-time data, such as weight-on-forks and maintenance reminders. This system is then enhanced with built-in component safeguards and comprehensive self-diagnostics that help drive down operating costs. Users benefit from operator comfort, smooth operation, easy maneuvering, and high efficiency.
Simultaneous function control handles. Created as an ergonomic enhancement, this feature enables operators to control the direction of travel, speed, lift and lower, and horn with a single control handle, and perform functions simultaneously, increasing productivity and efficiency.
Advances to come
As these and other innovations gain wider acceptance in the marketplace, two technology breakthroughs lie just over the horizon.
Radio frequency identification (RFID) appears poised to become the method of choice for tracking materials and gathering and transmitting information in distribution centers and throughout supply chains.
RFID requires no physical contact between the pallet or case and the scanning device. That means lift truck operators do not have to dismount or otherwise expend effort and time to record the receipt, movement or placement of loads. RFID codes also have the advantages of being highly secure, accurate and flexible.
While return on investment in RFID remains an issue, major retailers are driving its deployment. For example, Wal-Mart directed its top 100 vendors to RFID tag all pallets and cases shipped to its Texas distribution centers.
Meanwhile, RFID is being tested in a "living laboratory" at a Connect Logistics distribution warehouse in Edmonton, Alberta, that distributes beer, wine and liquor for the Alberta Gaming and Liquor Commission. The project involves the Tibbett & Britten Group/Exel Logistics third-party logistics firm, the IconNicholson technology services firm, and The Raymond Corporation.
A portion of the distribution center has been configured with RFID hardware, tags and software. The work includes equipping each of several types of lift trucks, pallet and carton storage locations, and dock doors for RFID. The testing will measure the benefits of RFID for various applications and help determine how the technology can be deployed for optimal efficiency in distribution centers.
While lift trucks do not directly send or receive RFID data, they must be properly tested and outfitted to host the technology. That means mounting RFID readers to ensure accurate communication with the system and making sure that operators can view the data easily and comfortably – at a convenient height and on a properly lit screen. It also means ensuring that the RFID system does not interfere with the truck’s operating systems, and vice-versa.
Fuel cell technology
Another major development in lift trucks is hydrogen fuel cell technology. While fuel cells are still in their infancy and face a large cost disadvantage in the automotive market, they seem to have a ready niche in powering electric lift trucks. That is because they would replace batteries and generate significant savings through longer run times, lower maintenance, and the elimination of battery-charging infrastructure.
Fuel cells require only a refueling station where lift truck tanks are filled with hydrogen fuel. A major distribution center today may devote 5,000 to 50,000 square feet of space for battery charging and service. Upon conversion to fuel cells, that space can be filled with racking. In addition, people formerly devoted full-time to battery care and maintenance can be reassigned to revenue-producing work.
Fuel cells run cool and are extremely clean. Because they can be readily configured to fit the battery compartments of existing trucks, virtually all lift trucks in a given fleet can be retrofitted. All these advantages make a strong near-term financial case for fuel cells. Industry observers expect to see at least some distribution centers operating with fuel-cell forklifts by 2006 or early 2007.
Still more to come
As these breakthroughs unfold, manufacturers will continue to produce incremental improvements that enhance truck uptime and efficiency, and operator comfort and productivity.
Ergonomics is a major issue; potential improvements remain in a host of operator comfort details, such as more mobility in the operator’s compartment, placement of padding for weight relief, and locations of elbow rests.
Other developments could include features such as:
· Trucks that automatically weigh pallet loads and use RFID to check the actual weight against the expected weight stored in the computer. Incorrect shipments are a major source of losses in distribution businesses.
· Use of laser systems to identify centerlines on pallets, making it easier for operators to locate or properly position pallets in dark aisles.
· Use of computerized design methods like finite element analysis to fine-tune the use of materials in trucks and thus stretch capacity and height limitations while keeping manufacturing costs down.
Lift truck technology development is a constant process of creating and testing improvements that ultimately lower the user's cost per pallet handled.
About the Author
James B. Bennett III is Vice President of Sales and Dealer Development with The Raymond Corporation, a manufacturer of electric lift trucks for the warehousing and distribution industries, based in Greene, N.Y.