Our project is to design a portable cart suitable for families and individuals to carry heavy objects. According to our market research, we found that most of the carts on the market can be divided into two categories. One is that it can carry heavy goods, but it is not easy to carry and takes up a lot of space when idle; the other is that it can be folded and carried but can not carry heavy goods, such as luggage. So we hope to design a cart that can not only meet the needs of the family, but also be easy to fold.
In the process of carrying out the project, we first carried out the time planning, which took 13 weeks in total. After that, we conducted market research and made QFD chart according to the survey results. After the preparatory work is completed, we will carry out the preliminary conceptual design, with a total of six preliminary concepts. We select the most suitable final design according to our design objectives and production process, and constantly improve it in the detailed design stage. Finally, we made the corresponding 3D model.
The portable cart designed by us mainly meets the three purposes of large carrying capacity, foldable and small space after folding. From the QFD diagram we designed, we can find that the most important engineering feature is the width of the chassis, followed by the length of the chassis. Therefore, in order to make the portable cart meet our purpose, we refer to other similar carts to carry out the detailed design on the size of our designed cart. We want the chassis to be 23cm wide and 40cm long.
The most important point of the cart we designed is its portability, so we use the folding chassis to make it occupy less space after folding. In this way, the portable cart is convenient to carry, especially in such occasions as the transportation of luggage, the use of the portable cart can help us to reduce the burden. However, most of the carts on the market can not do this, so we hope that our portable carts can achieve such a goal: to find a balance between the requirements of heavy load and the requirements of convenient carrying. This is our ultimate goal in designing the cart.
The portable cart designed by us can be divided into two main parts: chassis and push rod. The chassis part is composed of two engineering plastic plates with dimensions of 230mm * 233mm and 230mm * 167mm respectively, which are connected by hinges. There is a pin like plug plate under the chassis, which is used to fix the chassis after deployment. Six universal wheels are installed under the chassis, respectively near the four corners and the joint of the two plates. The connection between the chassis and the push rod is completed by a special connecting device. It can realize the fixation and rotation of the push rod on the chassis. The push rod is composed of two sections of sleeve. There is a nut at the joint of the sleeve to fix the stretched push rod. When the cart needs to be folded, we first need to pull out the plug plate used to fix under the chassis, then fold the chassis, and then loosen the nut on the push rod, then shrink the sleeve rod and fold it to the chassis, so that it will fold up.
