This invention relates to an automatic bag opening device, and in particular, one that automatically opens and removes the contents of shipping bags.
Shipping bags contain various types of powdered or granular substances such as grain, flour, other foods, chemicals, and pharmaceutical powders or granules. A wide variety of substances are in powdered or granular form ranging from foodstuffs to industrial raw materials. Such substances include, for example, granular sugar, glucose, defatted powdered milk, starch, rice bran, spices, cement, fly ash, carbon black, salt, detergent, wheat, rice, corn, soybeans, malt, silica, aluminum oxide, titanium oxide, calcium carbonate, pulverized coal, lime, soda ash, food mix powders, wheat mix powders, soup powders, petrochemical powders, pharmaceuticals, cosmetics, blended fertilizers, phenol resin, polyethylene resin, ABC resin, PVC powder, polypropylene powder, and powdered or granular paints.
After being manufactured at a manufacturing facility, these substances are shipped to market in bags or plastic containers. Shipping is usually by ship, rail, or truck. Upon arrival at small or medium size plants, workers perform the operation of opening the bags and pouring their contents into a container, typically a hopper. Large scale plants and factories use automated equipment due to the volumes involved. In smaller plants, such operations are performed manually.
This manual operation requires heavy labor on the part of workers, especially when the bags are heavy. Workers are exposed to dust arising when the contents of the bags are poured out. If the substances are harmful or poisonous, the work environment is hazardous. For occupational safety, workers must wear a dust mask when opening the bags and pouring out any hazardous substances.
The work of opening and emptying bags creates a severe working environment involving heavy labor. The working environment is made worse by the need for workers to wear dust masks. In addition, the ill effects and psychological burden brought about by handling poisonous or virulent substances creates major problems in the workplace environment.
A bag opening device opens and empties bags of these various substances. Several types of bag opening device are already on the market. A brief description of typical examples of these conventional bag opening devices follows.
First, as the most general bag opening devices, devices such as an "automatic bag opening system, " "automatic bag opening device," "automatic bag opening equipment, " and "automatic bag opening machine" are on the market. These devices commonly have four functional mechanisms: (1) a mechanism to supply to the device bags filled with various powdered or granular substances, (2) a mechanism to feed the bags into the device, (3) a mechanism to open the bags and discharge their contents, and (4) a mechanism for processing the emptied bags. Since the four mechanisms are mounted on a large frame, the device is necessarily large, thus requiring a large area for its installation. It is difficult to install such devices in a small plant where space is at a premium.
An alternative device structurally different from the mechanism just described is a "bag opening hopper mechanism," which includes a fixed blade in a hopper over a vacuum device. Bags are suspended against the fixed blade which cuts a bag bottom to empty the bag's contents. However, variations in the weight and shape of the filled bags sometimes makes this device unusable, thereby limiting its range of application.
Unexamined Japanese Patent Application No. HEI6--40441 (1994), discloses a device intended to overcome these drawbacks in the prior art. The application discloses conveyance means for conveying the bags, a movable table for receiving the bags, means for standing the bags upright, an insertion tube having an air-blowing outlet, and a means for cutting the bag. The device maintains the interior of the bag at a positive pressure to remove the contents in a short time while leaving very little residue inside the bag.
However, a detailed analysis of this and the prior art previously described reveals the following unsolved problems.
First, the devices are far larger than they should be from the viewpoint of downsizing, which seeks to make the functions of the device as a whole integrated and compact, thereby reducing the installation space required. Second, the emptied bags are treated as trash waste products, with no thought given to recycling.