CHAPTER 1

INTRODUCTION

1.1 MOTORIZED HAMMER

Hammering machine is designed with mechanical arrangement in which movements are controlled by motors with cam arrangements.

When the power is supplied to the 12v Dc wiper motor, Cam arranged is attached with hammer tool. The rotary motion for the cam is given by the motor since the cam is coupled with the motor shaft. Hammer. The pin is welded with the cam eccentrically. When the pin reaches the lower position the hammer is lifted upwards and when the pin reaches the upper position the hammer is released. Due to this the impact load will be acting on the hammer table which is clearly shown as in the above diagram. So the required operation of hammering is easily made.1.1.1 COMPONENTS1. DC motor2. Battery3. Crank lever mechanism

4. Hinge

5. Hammer

6. Work piece

1. DC MOTOR

At the most basic level, electric motors exit to convert electrical energy into mechanical energy. This is done by way of 2 interacting magnetic fields- 1 stationary and another attached to a part that can move. High torque capabilities. There are three major components to a wiper motor:

Motor

Rotary to linear motion converter mechanism

Parking switch

The mechanism to convert rotary motion to linear motion is very straight forward, and its functionality is apparent from a visual inspection of a disassembled motor assembly.

A) Normal operation:

In this mode of operation, the dash switch is in the normal, or low speed, position, and internally, terminal 2 of the switch is connected to terminal 3. Current flows through the motor as shown by the dotted red line. The operation of the parking switch has no effect in this mode, as terminal 4 of the dash switch is not connected to any other terminal.

B) High speed operation: In this mode, the dash switch is in the high speed position, and current flow is as shown. This is basically the same configuration as the normal mode, except the power flows through the high speed brush rather than the normal speed brush. Internally, terminal 2 of the dash switch is connected to

terminal 1.

Fig 1.1 Dc MotorC) Wipers off, blades not in the parked position:

With the dash switch off, power is supplied to the motor through the contacts of the parking switch, and the motor continues to operate. Until the drive gear rotates to the point where the cam operates the switch plunger, the motor will operate at the normal, or low speed, just as if the dash switch were still on.

D) Wipers off, blades in the parked position:

When the drive gear has rotated to the point that the blades are in their parked position, the cam button on the drive gear depresses the parking switch plunger, operating the switch. Now, rather than the 12 volts as before, ground is applied to the low speed brush, shorting out the armature windings.

The magnetic field that had built up in the windings when 12 volts was applied will now discharge through the switch contacts, in very much the same manner as the operation of the primary windings in the ignition coil. This discharge current, shown as a dotted blue line, will be in the opposite direction as

the normal current flow, and will tend to reverse the rotation of the motor.Because the windings are now short-circuited, the discharge takes place very quickly, and the reversing energy lasts just long enough to stop the motor. The energy in the discharge is such that the motor will stop immediately! In fact, if your are holding the motor while testing this operation, hold on tight, because it stops so quickly that it will jump out off your hand if you are not careful.

Earlier models:

Earlier models are a bit simpler than the later models, as you might expect. Power is applied to the wiper motor at all times when the ignition switch is on, and the motor is grounded by the operation of the dash switch. As soon as the wiper blades move to some position other than the park position, the parking switch inside the wiper applies ground to the motor. Thus, when the dash switch is turned off, the motor will continue to operate until the blades reach the park position. There is no field discharge current to assist the parking in this configuration, so the parking is not as crisp as in the later models.

2. BATTERY

A series, parallel or series-parallel grouping of cells is called a battery.

Generally, a cell can deliver a small current at low voltage. If higher voltage is required- a battery containing number of cells connected in series.If higher current is required a battery containing number of cells connected in parallel.If large current at high voltage is required- a battery containing number of cells in series and further connected in parallel.Usually a no. of cells connected in series placed in single container is called a battery. Working:

Lead acid batteries used in the RV and Marine Industries usually consist of two 6-volt batteries in series, or a single 12-volt battery. These batteries are constructed of several single cells connected in series each cell produces approximately 2.1 volts.

A six-volt battery has three single cells, which when fully charged produce an output voltage of 6.3 volts. A twelve-volt battery has six single cells in series producing a fully charged output voltage of 12.6 volts.

A battery cell consists of two lead plates a positive plate covered with a paste of lead dioxide and a negative made of sponge lead, with an insulating material (separator) in between. The plates are enclosed in a plastic battery case and then submersed in an electrolyte consisting of water and sulfuric acid Each cell is capable of storing 2.1 volts.

Fig 1.2 Battery Above a fully charged battery is connected to a load (light bulb) and the chemical reaction between sulfuric acid and the lead plates produces the electricity to light the bulb. This chemical reaction also begins to coat both positive and negative plates with a substance called lead sulfate also known as sulfation (shown as a yellow build-up on plates). This build-up of lead sulfate is normal during a discharge cycle. As the battery continues to discharge, lead sulfate coats more and more of the plates and battery voltage begins to decrease from fully charged state of 12.6-volts

One disadvantage of recharging a lead acid battery at a fixed voltage of 13.6-volts is the recharge time is very long. A typical 125-AH RV or Marine battery will take approximately 80 hours to recharge at 13.6 volts. Increasing the charge voltage to 14.4-volts will reduce battery recharge time for a 125-AH battery to 3-4 hours. Once a battery reaches 90% of full charge, the voltage must be reduced from 14.4-volts to 13.6-volts to reduce gassing and water loss.

The optional Charge Wizard automatically senses when a battery has a very low state of charge and automatically selects its boost mode of operation. Boost mode increases the voltage of a PD9100 Series converter/charger to 14.4 volts. When the battery reaches the 90% charge level, the Charge Wizard automatically reduces the charge voltage down to 13.6 volts to complete the charge. Again, this is a standard feature on our Marine Chargers.

Another disadvantage of recharging a lead acid battery at a fixed voltage of 13.6-volts is that once it is fully charged, 13.6 volts will cause considerable gassing and water loss. To prevent this from occurring the charging voltage must be reduced to 13.2-volts. The Charge Wizard will automatically select its storage mode of operation (13.2-volts) once the battery reaches full charge and remains unused for a period of 30 hours. This feature is standard on all of Progressive Dynamics Marine Battery Chargers.

At a charging voltage of 13.2 volts, the converter/charger will maintain a full charge, reduce gassing and water loss. However, this lower voltage does not provide enough gassing to prevent a battery condition called Battery Stratification. Battery Stratification is caused by the fact that the electrolyte in the battery is a mixture of water and acid and, like all mixtures, one component, the acid, is heavier than water. Therefore, acid will begin to settle and concentrate at the bottom of the battery.

3. CRANK LEVER MECHANISMMechanismAmechanismis a device designed to transform input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components such asgearsandgear trains, belt and chain drives,camandfollowermechanisms, andlinkagesas well as friction devices such as brakes and clutches, and structural components such as the frame, fasteners, bearings, springs, lubricants and seals, as well as a variety of specializedmachine elementssuch as splines, pins and keys

Planar mechanismAplanar mechanismis a mechanical system that is constrained so the trajectories of points in all the bodies of the system lie on planes parallel to a ground plane. The rotational axes of hinged joints that connect the bodies in the system are perpendicular to this ground plane.

Spherical mechanismAspherical mechanismis a mechanical system in which the bodies move in a way that the trajectories of points in the system lie on concentric spheres. The rotational axes of hinged joints that connect the bodies in the system pass through the center of these spheres.

Spatial mechanismAspatial mechanismis a mechanical system that has at least one body that moves in a way that its point trajectories are general space curves. The rotational axes of hinged joints that connect the bodies in the system form lines in space that do not intersect and have distinct common normals.

Crank lever mechanism`Acrankis an arm attached at right angles to a rotating shaft by whichreciprocating motionis imparted to or received from the shaft. It is used to convertcircular motioninto reciprocating motion, or vice versa. The arm may be a bent portion of the shaft, or a separate arm or disk attached to it. Attached to the end of the crank by a pivot is a rod, usually called aconnecting rod. The end of the rod attached to the crank moves in a circular motion, while the other end is usually constrained to move in alinearsliding motion.The term often refers to a human-powered crank which is used to manually turn an axle, as in abicyclecranksetor abrace and bitdrill.. In this case a person's arm or leg serves as the connecting rod, applying reciprocating force to the crank. There is usually a bar perpendicular to the other end of the arm, often with a freely rotatable handle orpedalattached.4. HINGE

A jointed or flexible device that allows the turning or pivoting of a part, A device for holding together two parts such that one can swing relative to the other, typically having two interlocking metal leaves held by a pin about which they pivot.Stainless steel does not respond to any coating materials, however, and so finishes will not adhere to a stainless steel hinge. As a result, stainless steel is more common for hidden hinges, while brass, bronze, and brass- and bronze-plated hinges are more common for doors. Brass and bronze, both copper-based alloys, are very sturdy metals that can withstand less-than-ideal weather conditions like rain, salt air, smog, and can form thicker hinges than stainless steel. Brass requires extra treatment to withstand salt water, but bronze is incredibly weatherproof, and used frequently in marine applications. They also respond well to finishes, so they can be affixed with a broad array of colors to complement many different paint coats. Copper: Copper makes up the base metal of solid bronze and brass alloys, or that used in bronze- and brass-plating.Galvanized: This electrochemical finishing process coats steel to protect it from rust.Japanned: This is a kind of lacquer from Italy, named after fashionable Asian embossments in the 17th century.Blued: This is a finishing process involving the passive oxidization of steel, which gives the material a bluish hue.

Fig 1.3 Hinges 5. HAMMER

A hammer is a handheld tool used to strike another object.Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer(often a power hammer) or a die. It consists of a handle to which is attached a heavy head, usually made of metal, with one or more striking surfaces. There are dozens of different types of hammers. The most common is a claw hammer, which is used to drive and pull nails. Other common types include the ball-peen hammer and the sledge hammer.

Certain specialty hammers may have Dead-blow hammers have a hollow head filled with small steel shot to give maximum impact with little or no rebound. Steel and composite handles usually have a contoured grip made of a synthetic rubber or other elastomer. Wood handles do not have a separate grip. Steel and composite handles may also be encased in a high-impact polycarbonate resin. The addition of this material around the handle increases shock absorption, improves chemical resistance, and offers protection against accidental overstrikes. An overstrike is when the hammer head misses the nail and the handle takes the impact instead. This is a common cause of handle failure.

Fig 1.4 Hammer CHAPTER 2DESIGN CALCULATION

2.1 DESIGN OF MOTORMotor power : 60 kw

Speed of the power : 440 rpm

Motor speed is directly proportional to the input voltage, E, applied to the motor terminals.

s = E/Ke

where,

s = Shaft speed, rad/sec

E = Input voltage applied to motor terminals, V

Ke = Motor voltage constant, V/(rad per sec)

1. Torque

T = 60P/2n

= 60*60/2*440

= 1302.17 N-mm2. Synchronous speed

Ns = 120*f/Pn

= 120*50/6

= 2000rpm

Pn no . of poles 6

3. Slip

= Ns-N/Ns

= 2000-440/2000

= 0.78

4. Diameter

T=/16D

=1302.17*10/45*(/16) = D

D = 52mm

5. Horse power

1 HP = 0.746 KW

1 /0.746 HP = 1KW

HP = 60/0.746

= 44.76 KW

6. Locked rotor current

IL = 577*HP*KVA/E

= 577*44.76N*5.6 / 440

= 361 Amps

kva code F motor constant 5.6

.

CHAPTER 3

FABRICATION DETAILS 3.1 MATERIAL SELECTION

Hammer:

Hammer heads are made of high carbon, heat-treated steel for strength and durability. The heat treatment helps prevent chipping or cracking caused by repeated blows against other metal objects.Heads are made up of copper, brass, babbet metal, and other materials.Steel and composite handles usually have a contoured grip made of a synthetic rubber or other elastomer.

Hinge:

Copper: Copper makes up the base metal of solid bronze and brass alloys, or that used in bronze- and brass-plating.

Galvanized: This electrochemical finishing process coats steel to protect it from rust.

Brass and bronze, both copper-based alloys, are very sturdy metals that can withstand less-than-ideal weather conditions like rain, salt air, smog, and can form thicker hinges than stainless steel.

Cam mechanism:

The rotary motion for the cam is given by the motor since the cam is coupled with the motor shaft. Iron casting with steel and phosphor bronze.Medium speed with automatic generation is applicable.Very accurate machining is required.33.2 LIST OF MATERIALSS.NOCOMPONENTSMATERIALSQUANTITY

1HammerSteel & Composite1

2HeadCopper & Babbet Metal1

3HingeGalvanized Steel2

4Circular discMild Steel & Phosphor Bronze1

5D.c motor-1

Table no 3.1 List of Materials3.3 MOTORISED HAMMER CONSTRUCTION

The motor is fixed at the bottom of the frame. The distance between the motor and hammer is adjusted in such a way to avoid slip and to make a proper power transmission to the hammer. The cam mechanism mounted with the shaft.

The electrical hammer is a device used for forging the metal, bend removing forsteel bars and also used for sheet metal works.

Fig 3.1 Motorized Hammer 2D Diagram3.3.1 WORKING PRINCIPLE

When the power is supplied to the 12v Dc wiper motor, Cam arranged is attached with hammer tool. The rotary motion for the cam is given by the motor since the cam is coupled with the motor shaft. Hammer. The pin is welded with the cam eccentrically. When the pin reaches the lower position the hammer is lifted upwards and when the pin reaches the upper position the hammer is released. Due to this the impact load will be acting on the hammer table which is clearly shown as in the above diagram. So the required operation of hammering is easily made.3.3.2 CAD DIAGRAM

Fig 3.2 Motorized Hammer 3D Diagram3.4 ADVANTAGES

Automatic process

Easy to operate

Maintenance is less

Implementation is easy

DISADVANTAGE

Large size of specimens cannot be hammered.

APPLICATIONS

It is applicable in forging process and also applicable in seed crushing process etc.

3.5 COST ESTIMATIONS.NOCOMPONENTSNo of QUANTITYCost in Rs

1Hammer1 300

2Head1 300

3Hinge1 250

4Circular disc1 250

5D.c motor11550

6battery11000

7Bolt & nut 4 50

8welding- 500

9Stand 11000

TotalRs.4200

Table no 3.2 List of MaterialsCHAPTER 4

CONCLUSION

This project is to increase the productivity & time saving for forging the work piece. In this project cam mechanism is used to convert the motion. It reduces the man power requirement. It is a simple machine, easy to operate and also transfer from one place to another. Maintained cost is less . its widely used in small scale industry , workshop, etc

REFERENCE

Theory of machines by r. S. Khurmi,j.k. gupta eurasia publishing house, 2005

Electric motors and drives: fundamentals, types and applicationsby austin hughes, bill drury21