It is inconvenient to rely on human power to open the lid of jars, and thus lid opener was invented. Up to now, there have been many types of lid opener on the market with different advantages. We found a lid opener that can change its radius based on the radius of the lid, which broadens its application scope. However, due to its design of gear and rack, it can unscrew the lid and is unable to screw a lid.

Based on this product, we came up with several schemes to add the function of screwing the lid, including scalable gears scheme, blocking gear scheme and coaxial rotation scheme.  Finally, we chose the feasible one, adding an additional gear next to the original one and designed our project. We also made a model.

We want to develop a lid opener with several characteristics. Firstly, it must save users’ strength to open the lid since this is a lid opener’s original function. Equally important, it can both screw and unscrew the lid based on users’ need. Its radius should be changeable to adjust to the size of the lid. Then it is supposed to be small and light enough so users can carry it conveniently. As a small tool, it should be as cheap as possible. Besides, the advantages like flexibility, easiness to clean and so on are also welcomed if possible.

We designed a developed lid opener. The whole lid opener is divided into several parts——skateboard, two handles, two gears and racks. The side handle is responsible for changing the radius by the transmission of gears and racks. When the clamping part clamps the lid, users can rotate the central handle to screw or unscrew the lid.

Base on the design, we have made the 3D model and drew the detail drawings. After analyzing the manufacturing process, we made an actual sample. While it still has many flaws due to the limitation of manufacturing, it basically achieves our target.