Mechanical World

Today we will discuss working of Rocket engines. Rocket engine is the very popular engine about which everyone want to know. Today I am discussing this topic. Rocket engines works on both liquid and solid fuel of combination of both. Liquid rocket engines further subdivided into two types mono-propellant and bi-propellant systems. Mono-propellant engines operate either as a simple cold gas system or apply a catalyst for an exothermal decomposition of the propellant, such as hydrazine (N2H4) or laughing gas (N2O). Generally these type of engines are only in use for low thrust satellite propulsion systems. Typical bi-propellant engines use either earth storable propellants, generally combinations of nitric acid or its anhydride with derivates of hydrazine,  asymmetric di-methyl hydrazine or mono-methyl-hydrazine (MMH), mixtures of storable and cryogenic propellants, liquid oxygen and kerosene or fully cryogenic, liquid oxygen and liquid hydrogen. Although rocket engines sh...

Today we will discuss about types of gearbox used to power transmission in automobile industries. An automobile requires high torque when climbing hills and when starting, even though they are performed at low speeds. On other hand, when running at high speeds on level roads, high torque is not required because of momentum.  So requirement of a device is occur, which can change the vehicle’s torque and its speed according to road condition or when the driver need. This device is known as gearbox box. In an automobile various gearboxes are used which allow the vehicle to obtain different torque and speed combination. These are as follow Types of Gearbox: Basically Gear box is divided into two types according to the transmission. These are- 1. Manual Transmission Gearbox: In this type of transmission different speed ratio or gear ratio is selected by the driver manually. Some special skill of driving is required to operate this type of gear box. According...

Today we will discuss about continuous variable transmission. We also discuss about advantages and disadvantages of CVT transmission.  Till now we know that we use gear box to change the torque according to the driving requirement. For this we have four to five gear ratio which we shift and change the gear. But CVT is an automatic transmission that can select any desired drive ratio within its operating range. Unlike a conventional four or five-speed transmission, CVT is an infinite speed ratio transmission. In the manual gearbox one problem facing that the one speed ratio is not fully efficient in the desire range. So the manufactures have to work on a new system which can obtain infinite speed ratio and there is one unique speed ratio for one speed. This is the basic idea of CVT.  Principle of CVT Transmission: As an ordinary gear box CVT also works on the same gearing principle that when we attached a big driving gear to one small driven gear we obtain high...

Pedal Operated Hacksaw Operating a hacksaw manually is a very tiring and time consuming task. It requires a lot of manual effort and delivers uneven cutting. Operating a electrical hacksaw does deliver good results but consumes a lot of energy. So here we propose a semi automated hacksaw using pedal power. Here we design and fabricate a hacksaw that is run by pedal power and achieves even cutting with very less efforts. Here we use a chain sprocket arrangement to transfer power from pedals to hacksaw. A strong and firm base frame allows for efficient power transfer between the system. We use bearings and mounts to mount and setup the entire system and ensure a smooth circular motion of pedals. Now we attach a hub to the other sprocket. This hub is connected with a connecting rod which moves with the hub in order to produce a lateral motion. We now develop a supporting frame and connect a saw to the other end in order to achieve desired cutting movement of saw. We also attach ...

Automated Portable Hammering Machine Hammering is the most widely used industrial as well as construction activity. Hammering or screws, metal sheets, parts etc requires a lot of time and effort. So here we propose an automated hammering system that allows for fully automatic hammering process. This allows for accurate, fast and automated hammering wherever and whenever needed using a 12V battery. The person just needs to insert workpeice and start the hammering machine. This machine can be used for automatic hammering work as and when needed. We here use a dc motor in order to move the hammer. The DC motor consists of a pulley attached to it which is connected to a larger pulley for efficient power transfer and to increase torque. This large pulley is connected to a shaft that has a connecting rod attached to it. This rod is used to achieve lateral motion from the spinning shaft. We now connect the other end of hammer to this connecting rod through a mid swinging arrangement in ...

Polygon: Short key  : POL Polygon is the shape which has more than two sides and each side is equal length. There are two methods to draw polygon in AutoCAD. 1.  With the reference of a circle: This method is used when we know the radius of the polygon. In this method first draw a circle whose radius is same as the polygon radius and then follow this method. Select polygon tool from quick access toolbar or by short key POL enter. Now enter number of sides of the polygon. After it specified the center point of polygon by clicking the left click of mouse at the center of the circle. Now press I enter to draw the polygon inside the circle or press C to draw the polygon at circumscribed(outside) to the circle. Now enter the radius of the polygon. Now delete the circle. Example: Draw a polygon who has eight sides and whose radius is 6. Solution: Draw a circle whose radius is 6. POL enter. 8 enter Select the center of the circle. Press I for i...

Now you know the basics of autocad software, you’re ready to begin drawing! This article introduces you to some basic commands used in drawing with AutoCAD. The drawing tools are the tools which are used to create various shapes with the accurate dimension. Before starting this drawing you should re memorize the following instruction which used in designing. 1. Understood coordinate system 2. Learn about the basic like plan and elevation of a 3D object.   Starting the drawing tool > Line tool: There are two methods to select any drawing tool in AutoCAD. First by select is from the quick access toolbar and second by using short key. We prefers second method because when the new version of any software is coming there is no change in short key but the place of the drawing tool bar may be changed. We will explain both methods you may choose by yourself. Line tool: Line tool is a tool by which we can create a line at any angle or at any path with accurate d...