Product, or materials handling is the problem of moving small quantities of goods over relatively short distances compared with the longer-haul product movement by transportation companies. It is an activity that takes place in warehouses, production facilities, and retail stores, and also between transportation modes. The concern is to be able to move the goods with speed and low cost. Because the handling activity must be repeated many times, what may be minor inefficiencies in any one trip can add up to substantial diseconomies when taken over many products and a period of time. Materials-handling equipment design and methods have shown more progress in improving efficiency than perhaps any of the other logistical activities.
• Equipment
It is doubtful that many reading this text are very familiar with the basic equipment used in the materials-handling activity. Materials-handling activities are usually invisible to those who have not been exposed to them on the job, and a trip through a warehouse is rarely J glamorous enough to be included in a school club, or church tour. Л
brief description of the basic types is in order.
Movement equipment. A variety of mechanical equipment is available for handling a wide range of product sizes, shapes, volumes, and weights. The more popular types are (1) tracks, (2) conveyors, and (3) cranes.
Trucks. Trucks arc mechanical assists for moving materials that if moved by hand would be too heavy, too slow, or too fatiguing. These trucks range from hand-powered platforms to towing tractors.
Probably the most widely used truck is the counterbalance forklift. It is commonly used in conjunction with pallets. Pallets are platforms on which goods are stacked, serving to unitize the load being moved.. The under side of the pallet is designed to accept the blades of the truck so that the entire pallet load can be moved at one time. The truck-pallet method of movement has proved to be both flexible and efficient. This helps to explain the popularity of its application.
Other versions of the truck are also available. Normal variations of the forklift track include (I) its lifting capacity, (2) its lifting height, (3) whether it can operate in narrow, aisles, (4) how it is powered (manually or by mechanical power), and (5) the speed with which it moves.
More-radical designs have also found use in special cases. The sideloader - has a side reach and carries its load in line with the direction of travel. This truck type has proved useful in handling long bulky loads such as steel tube, structural sections, plate lumber, and carpets. Another variation is to use a tow tractor to pull a number of platform trucks as a train. The forklift may also serve as the locomotive power for the train. Such trains are economical for larger volumes moved over longer distances. A popular application is to use the tow train to move finished goods between the production floor and the warehouse, which may be some distance away. Metal strips axe placed on the floor, and the path of the tractor is maintained by remote control.
Conveyors. The forklift truck is the most popular of the mechanical materials-handling aids. Next in popularity is the conveyor for small, bulky items. Conveyors are particularly useful for moving high-volume items along a fixed route.
There are two main types of conveyors: Gravity-feed and power-feed. Within these
types there are many styles such as wheel, roller, belt, slat, and screw. The gravity-feed conveyors use low-friction surfaces (wheels, balls, or rollers) lightly downgrade inclined (a drop of about 1/2 inch per foot) to move flat-surfaced goods or goods placed on flat surfaces. Power feed is used where goods must be moved upgrade, but is generally restricted to short distances due to the increased expense.
Уважаемый посетитель!
Чтобы распечатать файл, скачайте его (в формате Word).
Ссылка на скачивание - внизу страницы.