The currently available lunch bags or cooler bags are made with a liner, which is fixed and is not waterproof. When there is a spill inside of it, much of the bag can be stained and soiled and then the bag can not be cleaned thoroughly, because it is impossible to clean the layer between the liner and the exterior of the bag. If the liner is damaged, it can not be replaced and the bag is rendered useless. Because of the fact that lunch bags get dirty easily and can not be cleaned well and that the fixed liner can not be replaced once it is broken, lunch bags are deemed disposable items. For these reasons, lunch bags are made with cheap material and shoddy craftsmanship. Some lunch bags are made with fashionable designs and appear artistic, but it is a pity that unfortunately they are discarded sooner or later after they become too dirty to use. Because of the fixed liner, the cooler bags and lunch bags are only dedicated to their intended use and can not be applied to other usage.
I have designed a cooler bag/lunch bag with a detachable liner, which confers a dual use both as a cooler/lunch bag and a usual carry/shopping bag. When the liner is detached and folded up on the bottom of the bag, the cooler/lunch bag is converted to a carry/shopping bag. The liner can be made in different shape to fit in bags of different shapes.
The detachable liner is made of a complete piece of plastic, silicone or rubber is thus waterproof. The liner can be removed, cleaned or repaired and the cooler/lunch bag can be machine-washed too. The liner can be replaced whenever it is damaged. No matter how big and messy a spill is, the liner can be detached and the cooler/lunch bag is cleanable and reusable. This design allows the cooler/lunch bags to be maintained in good condition easily and makes the long-term use possible. Therefore, better materials, designs and craftsmanship are worthwhile for such cooler/lunch bags.
The convertible cooler/lunch bag of my design features a unique liner which is made of a complete piece of waterproof material such as a sheet of plastic, rubber or silicon without any stitch. The liner has a row of “+” shaped slits along its top margin, which correspond to a row of round studs along the top margin of the cooler/lunch bag and snap onto them to get attached to the interior of the bag. The liner is attached to its base, which has two longitudinal side walls and is attached to interior of the bag with velcro patches on its side walls. Each of the two side walls of the liner has two or more pairs of velcro strips. Each velcro pair consists of one hook strip and one loop strip. Each pair of hook and loop velcro strips attach to the corresponding pair of hook and loop velcro strips on the interior wall of the bag and attach the side wall of liner to the bag. The bag functions as a cooler/lunch bag when the liner is attached this way. When the cooler/lunch bag is to be used as a usual carry bag, the liner can be easily detached from the bag by disengaging its “+” shaped slits from studs on the bag. After the liner is detached, the pairs of velcro hook and loop strips on the side walls are attached to each other, which folds up the side wall lengthwise and flattens the liner. Then the flattened liner is folded up along the most pliable zone between the closed velcro pairs in a zigzag way and is stacked upon itself in its base. Then the base, which now contains the folded liner, is inverted, so that its bottom surface functions as a bottom of the carry bag while the base is immobilized and attached to interior of the bag by means of the velcro patches on its two side walls.
Each of the two side walls of the liner has two or more pairs of velcro strips 6. Each velcro pair consists of one hook strip and one loop strip 6. Each pair of hook and loop velcro strips 6 attach to the corresponding pair of hook and loop velcro strips on the interior wall of the bag and attach the side wall of liner to the cooler/lunch bag.
The liner 1 has a plastic base 7, which has two longitudinal side walls. The lower part of the liner is immobilized and is attached to the interior of the bag by means of velcro patches 8 on the side walls of its base.
Insulation material 9 is embedded in the wall of the cooler/lunch bag 5, which raises the surface of the liner 1 to a level that is flush with or above the row of studs 4, which then can be esthetically concealed with a overhanging flap along the top margin of the bag 5.