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 Couplings  1- Shaft transportation problem are usually available up to 7 meters length more length causes as. 2- To have greater length, it is necessary to join two or more pieces of shafts by means of couplings . 3- Connect the ends of two shafts together.  4- Transmit power from one shaft to other shaft.  5- Reduce the vibrations.  6- Provide mechanical flexibility. 7- Permit misalignment of shafts. Requirements of couplings  1- It should be easy to connect or disconnect.  2- It should transmit full power of shaft. 3- It should hold the shafts in perfect alignment.  4- It should have no projecting parts.  Types of couplings  1- Rigid Couplings . 2- Flexible Couplings . Rigid couplings  1- It is used to connect two shafts which are perfectly aligned.  Types of rigid couplings  1- Sleeve or muff coupling .  2- Clamp or split muff couplings .  3- Flange coupling.   > Protected type . > Un protected type . > Marine type  Sleeve or muff coupling 1- Sleeve or muff coupling is th

 What is Clutch  1- C lutch is a mechanical device and type of clutch used for engage and disengage power transmission from driving shaft to driven shaft.  2- Clutch is use where positive drive (torque transmit without slip) is required. 3- Clutch is a mechanical device and type of clutch used for engage and disengage power transmission from driving shaft to driven shaft.  4- Positive clutch is use where positive drive (torque transmit without slip) is required.  5- In positive clutch two machine elements are used, one element is rigidly fixed to driving shaft.  6- And other machine element is free to slide axially on splined driven shaft and it helps for engage or disengage clutch. 7- Machine elements of positive drive have jaws which help to connect shaft (driving shaft and driven shaft).  8- Jaws may be in square shape, triangular shape or gear toothed.  9- According to use different type of jaw machine element is used in clutch. Application of positive clutch 1- They have very

Hydraulic Symbol of hydraulic components  1- It is a graphical representation of the hydraulic components in a hydraulically operated machine.  2- It gives us an idea how control valves, actuators, pumps etc., are interconnected. Example of hydraulic circuit  1- This hand pump has been designed for use on machines which require emergency lowering, or for pilot supply on access platforms and lubrication circuits. Hydraulic fluids  1- A hydraulic fluid power system may be defined as a means of power transmission in which a relatively incompressible fluid is used as the power transmitting media.  2- The term fluid has come into general use in hydraulics to refer to the liquid used as the power transmitting medium.  3- The hydraulic fluid has the following primary purposes  I)- To transfer power  II)- To lubricate parts  III)- To avoid corrosion  IV)- To remove impurities  V)- To dissipate heat  VI)- To seal clearance between parts Properties of hydraulic fluid  Viscosity  1- Viscos

 What is Spirit level  1- Levelling of the machine is a very important operation before proceeding to conduct geometrical tests.  2- A precision  spirit level  is used to level the machine tools accurately.  3- Sprit level consists of a curved glass tube called 'VIAL 'containing industrial alcohol 'spirit' and a bubble of 'AIR' trapped in the tube.  4- The spirit and the bubble are both acted upon equally by the force of gravity. 5- Since the spirit has a higher density, it is pulled down to the bottom of the tube and the bubble always floats to the top.  6- The vial is set in a cast iron base and adjusted such that the bubble rests at the center of a scale when the base is horizontal. How to measurement Precision spirit level  1- Spirit levels used for high precision measurements should have a sensitivity of about 0.02 to 0.05 millimeter per millimeters for each division.  2- If the movement of the bubble by one division corresponding to a change in slope of

 What is Foundation Bolt 1- Machines are generally subjected to vibration or forces. Due to this the machines are likely to shift or move from their positions.  2- To overcome this, the machines are fixed to the ground with the help of devices called foundation bolts.  3- These foundation bolts do not have a specific shape or head like hexagonal or square bolts. 4- The length of the shank is according to the thickness of nut and the thickness of machine base.  5-  This odd shaped part holds the machine firmly to the ground. Types of foundation bolt   1- Eye foundation bolt . 2- Lewis foundation bolt . 3- Cotter foundation bolt . 4- Rag foundation bolt . 1- Eye foundation bolt   1- Simple forms of these bolts can be quickly forged from mild-steel. The stationary engines and machines are fixed on these bolts. These bolts are suspended in the hole and cement grout is then poured to fill the space around them. 2- Lewis foundation bolt   1- It is a rectangular shank bolt with one side

Oxygen acetylene Gas Welding torch or blow pipe are used  1- Oxygen and acetylene gas pressure is reduced by gas regulator.  2- These gases are supplied through suitable hose to welding torch.  3- Gases are mixed in mixing chamber of welding torch and supplied to welding tip or nozzle.  4- The gas mixture is burnt to produce a flame to carryout welding operation.  5- There are two types of Gas welding torches,        • Low pressure or injector type        • High pressure or equal pressure type. 6- Low pressure torches are used with acetylene pressure obtained from acetylene generator at a pressure of 0.02 bar (less than 1 psi).  7- High pressure torches are used with acetylene stored in cylinder at a pressure of 8 bar. Low pressure or injector type torch  1- It is operated by low pressure acetylene at 0.02 bar.  2- As acetylene is at low pressure, it is necessary to use oxygen at high pressure (approximately 2.8 bar). 3- Oxygen enters into mixing chamber through passage locate