debashis khan -seminar

8/2/2019 Debashis Khan -Seminar

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Presented byName Debashis Khan

Trade - Mechanical

Roll - D105050005 No 10260TopicVarious Mechanical JointsGuided By Milan Kr Mondal &

Amitesh Chakraborty


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Mechanical joint is a part of a machine which is used to contact another

mechanical part or mechanism.

Mechanical joints may be temporary or permanent. Most types aredesigned to be disassembled when required.

Mechanical joints are much cheaper and are usually bought ready

assembled.


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1. KNUCKLE JOINT

2. SCREWED JOINT

3. COTTER JOINT

4. RIVETTED JOINT

5. WELDING JOINT


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1. KNUCKLE JOINT

A knuckle joint is used to connect the two rodswhich are under tensile load , when there is arequirement of small amount of flexibility orangular moment is necessary.

MAJOR COMPONENTS-

i) Eye endii) Fork endiii) Knuckle pin

APPLICATIONS-

i) Tie roof joint for roof truss.ii) Tension link in bridge structure.iii) Link ofroller chains.iv) Tie rod joint of jib cranes.

v) In tractors.
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The bolted or screwed joint is very popular method for fastening components together.The prime reason for selecting bolts as opposed to welding or rivet is that the connectioncan be easily released allowing disassembly, maintenance & inspection.

COMPONENTS OF BOLTED JOINTS:-

i)Boltii)Nut

ADVANTAGES OF BOLTED JOINTS:-

i)Screwed joints are highly reliable in operation.

ii)Bolted joints are convenient to assemble & disassemble.

iii)Wide range of screwed joints may be adopted to various operating conditions.iv)Comparatively cheaper.

DISADVANTAGES OF BOLTED JOINTS:-

i)The main disadvantage of bolted joints is the stress concentration in the threaded

portions which are vulnerable points under variable load conditions.


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1.Through bolt

2.Tap bolt

3.Studs

4.Caps screws

5.Machine screws

6.Set screws

7.Foundation bolts such as Rag bolt , Hoop bolt , Lewis foundation bolt ,

T-headed foundation bolt etc.

COMMON TYPES OF NUTS:-

1. Nylock full nut 2.Domed nut

3.Philidas self locking nut 4.Hexagonal nut

5.Wing nut 6.Flanged nut

7.Castle nut 8.Slotted nut


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Cotters are temporary fasteners & are used to hold two parts together where the parts aresubjected to axial forces only. A cotter is a wedge shaped piece of mild steel often

rectangular in section. A cotter is tapered on one side or both sides.A joint formed by using a cotter is called a COTTER JOINT.

Types of cotter joints:-

1. Socket & spigot cotter joint

2. Sleeve & cotter joint

3. Strap joint

Advantages:-

Cotter joints are advantageous in that they are simple in design & allow a convenientassembly & disassembly of the joint.

Application:-Cotter joints are often used to connect a rod which is subjected to axial loading, either toanother rod or to some machine part such as a cross head, baseplate, connecting rod end of asteam engine etc.


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1. WELDING JOINT

Welding is a process of joining two similar or dissimilar metals by fusion, with or without

the application of pressure & with or without the use of filler metal. The fusion takes placeby means of heat obtained from blacksmiths fire, electric resistance or by chemical reaction.

The following are the main key features of welding:-

1. Lighter than riveted or bolted structures.

2. Maximum efficiency & greater strength.3. The addition and alterations can be easily made in the existing structure.

4. The welding provides very rigid joints.

5. Less time required.

Disadvantages of welding joints:-1.Due to uneven heating & cooling members may get distorted & residual stress may develop.

2.It requires highly skilled labour & supervision.

3.Inspection of welding joint is more difficult than other joints.


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Fusion Welding Pressure Welding

Homogeneous Heterogeneous

Brazing SolderingGas Welding

Electroslag

High Energy Beam

Electric Arc

MIG

TIG

Shielded Metal ArcStick

Friction Welding
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FLAT

HORIZONTAL

VERTICAL

OVERHEAD

INCREASING DIFFICULTY


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BUTT JOINT

STRAP JOINT

LAP JOINT

T- JOINT

CORNER JOINT


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1. Manufacturing of machine tools, auto parts, cycle parts, etc.

2. Fabrication of farm machinery & equipment.

3. Fabrication of buildings, bridges & ships.

4. Construction of boilers, furnaces, railways, cars, aero planes, rockets and missiles.

5. Manufacturing of television sets, refrigerators, kitchen cabinets, etc.

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