MECHANICAL ENGINEERING

THEORY OF MACHINES


OF.TMH/01



         
Fly Wheel Apparatus

This apparatus is designed to demonstrate the working principle of flywheel and its practical significance in industry. Flywheel is used to store rotational energy when the supply of energy is more than the required, and delivers when requirement of energy is more than the supplied.
This apparatus consists of flywheel mounted on a shaft and whole structure is attached to the base plate. Cord is wounded on the axle carrying dead weights and hanger. Students can calculate the inertia of flywheel by adding weights on hanger.

OF.TMH/02



         
Inertia In Rotational Motion Apparatus

This apparatus is designed to measure the inertia in rotational motion for different bodies. Whenever a body rotates at any angular velocity, inertia produces. The unit consists of a large disc and a small pulley. Inertia of three different bodies can be calculated by this apparatus.
1. Rod and point masses
2. Hoop
3. Disc
The body whose inertia is to be calculated is placed on the disc. The disc is then rotated with the help of a cord which is tied to the disc and passed over the small pulley. The cord has hanger and weights on its free end.

OF.TMH/03



         
Screw Jack Apparatus

This apparatus is designed to study the performance of screw jack. It is a device which is used to lift high loads with comparatively low effort.
The unit consists of one large disc and two small pulleys. Load is placed on the disc and effort forces are applied via two small pulleys.

OF.TMH/04



         
Disc Brake Apparatus

This apparatus is designed to calculate the coefficient of friction of disc break using different types of materials.
In this apparatus disc is mounted on a shaft which rotates with bearing action. Hub is attached to the shaft and dead weights are applied on the hub with hangers. This torque is balanced with the iron strip carrying load. Same procedure is performed while testing different materials.

OF.TMH/05



         
Relation Between Linear Speed And Regular Speed

This apparatus consists of wall mounted bracket on which stepped shaft is held to a main shaft. Strings are wrapped around the circumference of each step of shaft.
A single mass is attached at the end of each string. A handle is provided to rotate the shaft which can be locked by a retaining screw.

OF.TMH/06



         
Winch Apparatus

Winches are holding devices that are used to carry and lift the loads. They are widely used for transporting people or goods. Winches are the fundamental elements in crane whenever a dynamic pull is required from a flexible rope.
This apparatus consists of an effort wheel or pulley carrying rope and is driven by load hanger that is attached at the end of rope. The load wheel can easily be engaged with effort wheel gears.

OF.TMH/07



         
Worm And Wheel Apparatus

This unit is designed to study the performance of a worm and wheel mechanism. It is a mechanism that contains a circular gear and a rod on which tooth are made. This mechanism is used to convert or transmit circular motion to linear motion or vice versa.
The unit consists of a worm and wheel mechanism. Both are connected with pulleys to apply load and effort forces. To apply forces, cord and hanger are used.

OF.TMH/08



         
Wheel and Differential Axle Apparatus

This unit is intended for wall mounting and demonstrates the conditions of equilibrium on a differential pulley block. Three anodized Aluminum Pulleys of different diameter are fitted to a shaft mounted on ball bearings. The forces act on the one hand directly on the peripherals of the largest pulley, on the other hand via a loose pulley on two smaller pulleys.
Easy to interchange weights permit the load to be varied such that equilibrium is obtained.

OF.TMH/09



         
Wheel And Axle Apparatus

This apparatus is designed to study the performance of wheel and axle mechanism. This mechanism is used to lift the heavy loads with comparatively less effort.
The unit consists of two pulleys of different diameters. The pulley with larger diameter is termed as wheel and the other one is called axle. Both pulleys are fixed on same rod which is supported at its ends via bearings. Load is applied on axle with the help of cord and the effort force is applied on wheel to lift the load with the cord which has hanger and weights on its free end.

OF.TMH/10



         
Crank And Connecting Rod Apparatus

This apparatus is designed to study the working and characteristics of slider crank mechanism. Connecting rod and crankshaft are used in engines to convert linear motion of piston into rotational motion of crankshaft etc.
The unit consists of two arms connected to each other by a sliding link. This arm is termed as crank and the other arm is called slider arm or connecting rod. The scale on slider arm is used to measure the linear displacement while the scale on the circular disc shows the angular displacement.

OF.TMH/11



         
Slotted Link Apparatus

This apparatus is designed to demonstrate the concept and working principle of pure simple harmonic motion. As the crank rotates, it drives the bar in oscillating manner. Same mechanism is observed in piston and crankshaft motion in engine.
In this apparatus disc is mounted on bearing having holder on its surface and it is joined with a bar through holder. Disc has a rotational scale and its angle is checked at any position. Scale is placed with solid bar and bar displacement can be determined at any disc angle.

OF.TMH/12



         
Four Bar Chain Apparatus

Four-bar linkages are used to convert a uniform continuous rotation into a non-uniform rotation or oscillation. The apparatus has a disc with angular scale which is used to measure the exact input angle. The crank pin can be located at different radii on the disc.
The oscillating lever and connecting rod can be joined together in different lengths by knurled bolts.

OF.TMH/13



         
Whitworth Quick Return Apparatus

This apparatus is used to produce and analyze irregular reciprocating motion with slow feed and quick return. The model best demonstrates the transmission pattern of such an assembly. The input angle can be set by turning the crank and the output stroke can be red on a ruler on the slider.
The apparatus consists of two cranks, i.e. driving crank and driven slider crank, ruler and rotating disc on which driven crank is attached.

OF.TMH/14



         
Gear Train Model

This apparatus is designed to demonstrate the mechanism of compound gears. Through this apparatus students can inspect and calculate the changes in gear ratio, velocity ratio and torque ratio due to intermediate gears in compound gearing.
In this apparatus gear of different pitch circle diameter and number of teeth are meshed together and seated on base at same level. Pins are used to lock them and these gears are adjustable. These gears are adjustable and students can perform different experiments through changing the position of the gears, and different velocity ratio and torque ratio can be achieved.

OF.TMH/15



         
Gear Trainer Demonstrator Apparatus

This apparatus is designed to demonstrate the working and application of gear train. This apparatus explains all the parameters related to gear trains like torque ratio, speed ratio, importance of idler gears and direction of rotation.
This apparatus consist of three gears mounted on a bearing to reduce friction. Whole mechanism is attached with aluminum frame and it is operated manually. These gears have different sizes and they can be interchange to achieve different speed ratio and mechanical advantage.

OF.TMH/16



         
Cam And Follower Apparatus

This unit is designed to study the working of cam and follower mechanism. For example cams are used in I.C engines to open and close inlet and exhaust valves on time with great accuracy.
The apparatus consists of cam and follower, dial gauge and a protector. The protector is used to measure the angle of cam at any instant. As the cam rotates, the follower is displaced. Dial gauge is used to measure the displacement of the follower.

OF.TMH/17



         
Whirling Of Shaft

This apparatus is designed to demonstrate the concept of whirling in shafts and visualize its effects in heavy rotating machinery. When shaft rotates, transverse vibration produces in it. If the shaft is out of balance the centrifugal forces produces and vibration starts.
If the rotation of the shaft is equal to the natural oscillation of the shaft, then these vibrations are multiplied. In heavy machinery this phenomena is very dangerous and it must be controlled.
This apparatus consists of number of shafts of different lengths and diameters, center support for shaft and end support. Shaft is coupled with motor and speed of motor can be varied to inspect the vibrations at various speeds.

OF.TMH/18



         
Governor Apparatus

The unit is designed to study the performance of different types of governors. Governor is a device that is used to maintain a constant mean speed of rotation. The apparatus consists of three different types of governors.
1. Porter governor
2. Proell governor
3. Hartnell governor
The load can be changed on governors by placing or removing weights in case of porter and proell governors. But for hartnell governor, load is changed by altering the stress on spring. The rotational speed of the governor is controlled via a speed control knob.

OF.TMH/19



         
Static And Dynamic Balancing

This unit is designed to study the balancing of rotating objects. When an object rotates at any given velocity, it faces centrifugal force. This force unbalances the assembly which contains this object. The unit consists of a shaft which is supported by bearings on its both ends. Four masses are present on this shaft which can slide on the shaft and attain different angles as well.
A pulley is present on one side of the shaft which connects the shaft with motor so that shaft can be rotated. Two buckets, detachable pulley and metallic balls are also included in this apparatus to find out the unbalance in static position due to rotating masses. The motor is provided with power via a function generator.

OF.TMH/20



         
Ackerman Steering Apparatus

This apparatus is designed to demonstrate the concept of Ackerman steering system which is widely used in automobiles. The apparatus is model of Ackerman steering having angular scale on both sides in order to read relative deflection, pointers, a center bolt for rotation and a long screw to change the lengths of connecting arms.
In Ackerman steering, four bar chain mechanism is used in the turning of vehicle. Two front wheels must turn about the instantaneous canter which lies on the axis of the back wheel.

OF.TMH/21



         
Hooke's Coupling Apparatus

This mechanism demonstrate relative angular motion in degrees between two intersecting shafts through a cross member such as found the rear drive shaft of an automobile. The angle between input and output shafts is adjustable and indicated on an angular scale.

OF.TMH/22



         
Constant Velocity Joint

This apparatus is designed to demonstrate the working of constant velocity joints. In CV joint power is transmitted from the driving shaft to the driven shaft at constant velocity at any rotational angle without any reasonable increase in friction and play.
This apparatus consist of two axles containing CV joint at its one end and an angular scale at the other end. Whole mechanism is placed on supports, having angular scale at the bottom.

OF.TMH/23



         
Double Epicyclic Gear Apparatus

This apparatus is designed to demonstrate the concept of epicyclic gear train and its application in machines. Epicyclic gears is the combination of gears in which center of one gear rotates about the center of another gear.
In this apparatus there are two epicyclic gears coupled together. Epicyclic gears contain sun gear at center and three planet gears meshed with sun gear and outer ring gear meshed internally with the planet gears. Lock pins are used in the whole mechanism to provide different speed ratio or gear ratio and mechanical advantage. In this way students can perform different experiments in this apparatus and calculate gears efficiency at different gear ratio and torque ratio.

OF.TMH/24



         
Geneva Mechanism

It is a commonly used mechanism for producing an intermittent rotary motion from a uniform input speed.
The driven member, or star wheel, contains evenly spaced slots into which the roller of the driving crank slides into. As the drive wheel turns it enter the slots of the driven, or star, wheel and the mechanism enter its motion period. As the pin leaves the slot the drive wheel has been indexed and it continues to stay stationary until the pin rotates back around.

OF.TMH/25



         
Vibration Of Spiral Spring Apparatus

This unit is designed to determine the time period of spiral spring and its frequency. Spiral spring is a type of spring which is formed by a metallic strip wound around a rod at same point.
The apparatus consists of a shaft on which the spiral spring is attached. A metallic rod, containing masses at its edges, is used to deflect the shaft. The deflection can be measured through a protector and the extent to which the spring was deflected initially can also be found.

OF.TMH/26



         
Torsional Vibrational Apparatus

This apparatus is designed to demonstrate the phenomena of torsional vibration in shafts. Torsional vibration is angular vibration of an object commonly a shaft along its axis of rotation. Torsional vibration is often a concern in power transmission systems using rotating shafts or couplings where it can cause failures if not controlled.
In this apparatus bracket is mounted on the base plate and chuck is attached with the bracket. Shaft is griped with chuck and rotor is attached at the other end of the shaft. Torsion vibrations vary with length and diameter of the shaft and mass of the rotor.

OF.TMH/27



         
Bifilar And Trifilar Apparatus

This apparatus is designed to demonstrate the oscillation of pendulum with bifilar and trifilar suspension. Solid cylinder, hollow cylinder and a bar is suspended with two or three threads. In bifilar suspension, translational and rotational oscillations will produce and in case of trifilar torsional vibrations will produce.
Mass moment of inertia can be calculated by the period of oscillation of torsion oscillation. In this apparatus bracket is attached with the base plate. Cylinder or bar is attached with the bracket with two or three supports, length of the suspension thread can be varied by the threaded supports.

OF.TMH/28



         
Compound Pendulum Apparatus

The apparatus is designed to study the time period and frequency of compound pendulum. A pendulum consists of a cord which has mass at its one end and it is tied to a pivot point on the other end.
The unit consists of a metallic rod on which metallic balls are fitted on different locations. The rod is pivoted at any desired point.

OF.TMH/29



         
Universal Vibration Apparatus

This unit is designed to determine the time period and frequency of a cantilever beam. When a force acts on a vibrating body in such a way that it makes the body to keep vibrating at constant speed, it is called forced vibration whereas if a body vibrates freely without any external force acting on it, it is termed as free vibration.
The unit consists of a horizontal metallic beam which is pivoted on one side of frame and is free at other end. To suspend it in horizontal position, it is connected to the upper side of frame via a spring. The unit contains two exciters.
1. Linear exciter/Balanced exciter
2. Non-linear exciter/Unbalanced exciter

OF.TMH/30



         
Free Vibration Of Bending Bar

This unit is designed to study the characteristics free vibration of a bending bar. When a bar is loaded with some weight and given a deflection, it starts oscillating. The time period and frequency of oscillation depends on the mass and dimensions of the bar.
The unit consists of a rectangular frame on which the bar can be placed in any direction. The bar is fixed at one end and mass is added on bar at other end. The unit contains a proximity sensor as well which measures the time period and frequency of the vibrating bar. The waveform of the vibration can be seen by oscilloscope.