Sideloaders: the best choice for long loads.
For the routine handling of long loads, sideloaders offer safety and efficiency unequaled by any other type of truck. In fact, in many applications, sideloaders are the only practical means for moving such materials.
Almost all sideloaders are similar in overall appearance. Yet despite the fact that the sideloader market in the U.S. is fairly small - we estimate 200-300 trucks sold per year - there are a surprisingly wide variety of truck designs available. Choosing the best sideloader for your specific application will be easier if you first review what's available.
The wide range of sideloader designs is partially a function of the number of different industries that rely on these trucks. Typical users include:
* Steel service centers,
* Steel mills,
* Aircraft and aerospace plants,
* Lumber mills,
* Heavy equipment manufacturing plants,
* Automotive plants,
* Textile mills,
* Laminate and plywood manufacturing plants.
In addition, sideloaders are used for roll-handling in many industries, both in manufacturing environments and in warehousing.
The major division in sideloader design comes between trucks designed for indoor applications and trucks intended to work out-of-doors. Let's look at both types.
Sideloaders for indoor use
For most indoor applications, sideloaders are electric-powered and equipped with solid tires. Common uses include storage and retrieval in rack structures, dock work, and operations such as feeding machine tools.
When used in narrow-aisle applications, sideloaders serve as a kind of free-ranging stacker crane. In these applications, aisle width is a function of load width and weight, and is only marginally affected by load length. Typically, aisle width can be just 36 inches more than the width of the load itself, regardless of load length.
For safe operation, sideloaders may be equipped with wire guidance or rail guidance packages. Either form of guidance also permits higher travel speeds when operating within the racks.
In a well-designed rack installation, a sideloader can complete an average cycle in 3-4 minutes, producing a throughput rate of about 15-20 line items per hour.
Depending on the manufacturer, a sideloader may be designed for two-directional travel (forward and backward) with conventional steering, or for four-way travel with rotating wheels. Trucks in this latter category are sometimes called four-way travel reach trucks. They approach the storage position while travelling lengthwise, rotate their wheels 90 [degrees] and advance to pick up or deposit the load, and then switch back to lengthwise travel.
Heavier capacity machines are usually equipped with articulated suspension systems for maximum load and vehicle stability. When designed for two-directional travel, these bigger machines may also feature all-wheel steering, with independent steering of each end for improved maneuverability.
Load capacities range from about 2,000 lb to 25 tons and up. Depending on the manufacturer, maximum lift height can reach 35 ft. When lifting height exceeds about 25 ft, some manufacturers recommend using an operator-up model for faster and more accurate fork positioning.
Forks may be manually or hydraulically adjustable. Mechanical, hydraulic, and electric brake systems are available, depending on the manufacturer and load capacity. Trucks are powered by one, two, or four traction motors.
An interesting variation within the indoor sideloader category is a truck equipped with one or two operator-up cabs for orderpicking work. This design combines regular unit-load handling capability with the capacity to manually pick orders.
When the work is outside
The second half of the sideloader family consists of IC-engine-powered trucks - usually equipped with pneumatic tires - designed for handling loads out-of-doors, or in some industries, in indoor/outdoor applications.
The great majority of these trucks are equipped with diesel engines - typically water-cooled, four-cylinder, four-stroke direct injection. Gas-powered and LP-gas-powered units are available in some load-capacity ranges.
Frequently, drive power is transmitted through a hydrostatic transmission to the rear wheels, using a variable displacement pump. The forward and reverse speeds are therefore infinitely variable. Some European-made models use hydro-dynamic transmissions instead.
As is the case with indoor trucks, these sideloaders use a moving mast design. In addition, though, some trucks are available with a pantograph mechanism that enables the truck to stack two deep.
Sideloaders designed for outdoor use commonly have a tilting deck for load and vehicle stability. Hydraulic cylinders located on the load side of center-pivoting axles allow the machine to be tilted as needed to balance the load properly and to maintain full contact with the ground.
Most engine-powered sideloaders steer with the front axle and drive through the rear axle. For travel over uneven ground, many trucks feature a suspension system that transfers hydraulic oil between cylinders to equalize wheel heights. Maximum travel speeds vary from about 13 to 20 mph.
Standard models offer maximum lift heights of approximately 20 ft (with some downrating). Load capacities range from 3 tons to as high as 50 tons. Most sideloaders designed for outdoor use feature power steering, drum and/or oil-immersed disc brakes, and an enclosed cab as standard equipment.
Whether the application is indoor or outdoor, sideloaders are a cost-effective, highly flexible piece of equipment for handling long loads safely and efficiently. [Tabular data omitted]
PHOTO : Electric-powered sideloaders squeeze easily into narrow-aisle rack configurations while carrying long, heavy loads. This vehicle features wheels that rotate 90 [degrees] to give it four-directional movement.
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|Publication:||Modern Materials Handling|
|Date:||Oct 1, 1990|
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