12-07-2012, 04:56 PM
scissor jack design
scissor jack design .docx (Size: 3 MB / Downloads: 356)
Introduction
The most basic scissor jack design is truly engineering at its finest. With the power to
magnify input forces, scissor jacks allow us to raise vast loads using only a fraction of the force
ordinarily needed. My goal in this project is to design an efficient scissor jack capable of raising and lowering an object. As a screw-driven mechanical system, the jack will be manually operated and have at least 7 inches under load. The design will be transportable and storable. The design itself has gone through multiple stages of development. I have taken several possible failure modes into account and am confident that my design is efficient and safe.
The main and most important item I use for my project is a power screw. The function of a power screw is to transform rotary motion into linear motion. Common applications are machine slides, vises, presses, and jacks. A power screw can be used for raising weights or exerting forces in machines. Moreover, it can be used to raise or lower a weight by rotating it. The two most common power screws are the acme thread design and ball screw design.
Advantages of Foot Scissor Jack
There are few idea features that the Foot Scissor Jack will probably provide:
• A foot scissor jack rather from the conventional type (using hands).
- Common scissor jack is jacked using hand which we usually use to jack a load or an object such as vehicle and motorcycle. Other than that, the modified foot scissor jack can be used as an adjustable table or chair. The foot scissor jack made has been proven to be easier to jack an object compare to the conventional type of scissor jack since we have more muscle and energy in our leg compare to our hand. By adding our body weight into our leg on the foot paddle, the foot scissor jack will be jack even more easily compare to the conventional type of scissor jack.
Objective
My objective in this project is to build a foot scissor jack which operates using a foot rather from the conventional type (using both hands) without the use of any hydraulic system, pneumatic system, electronic and electrical system. Moreover, it will be a foot scissor jack driven by foot paddle. Furthermore, it must be a foot scissor jack which enables to raise or lower a load.
Besides that, my objective is to be creative and innovative while carrying out the project. Enhance the knowledge of engineering principles and concepts. Lastly is to be skillful in utilizing engineering mechanisms in a proper manner which involves practical engineering works & techniques, the important skills of designing, precise dimensioning, calculation, safety & precautions, experience, practice and finally come up with an excellent quality of product. Lastly, to understand all guidelines and consideration in designing a foot scissor jack.
Base part
The base part was entirely made from carbon steel. It consists of four legs and the working part at the center-bottom of the base part. The base part has to be very strong so that it can support heavy load, thus welding is consider very important in this part. Without good welding, the whole base might crack, fall apart and collapse. To make the four legs stronger, the legs were made it into L-shape instate of just four pieces of straight steel. Other than that, a flat piece of steel with larger surface area was weld at each of the bottom of the legs to decrease the pressure between the legs and the ground. The base part is made like the figure below:
Grinding
- Grinding is a process where an abrasive wheel is used as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the work piece via shear deformation. It can be used to provide surface finish or cut away hard material. The process was used to get the shape of the PVC turbine blades and to get a better finish off welds. A bench grinder and hand grinder were used.