Cotter joint pptx
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Transcript of Cotter joint pptx
![Page 1: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/1.jpg)
COTTER JOINTA cotter joint is used to connect rigidly two co-axial rods or bars which are subjected to axial tensile or compressive forces . It is a temporary fastening. A cotter is a flat wedge shaped piece of rectangular cross section and its width is tapered (either on one side or on both sides) from one end to another for an easy adjustment.
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Socket Cotter
Spigot
![Page 2: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/2.jpg)
APPLICATIONS OF COTTER
• 1. Connection of the piston rod with the cross heads2. Joining of tail rod with piston rod of a wet air pump3. Foundation bolt 4. Connecting two halves of fly wheel (cotter and dowel arrangement)
![Page 3: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/3.jpg)
Design of Spigot and Socket Cotter
Let P = Load carried by the rods,d = Diameter of the rods,d1 = Outside diameter of socket,d2 = Diameter of spigot or inside diameter of socket,d3 = Outside diameter of spigot collar,t1 = Thickness of spigot collar,
d4 = Diameter of socket collar,c = Thickness of socket collar,b = Mean width of cotter,t = Thickness of cotter,l = Length of cotter,a = Distance from the end of the slot to the end of rod,σt = Permissible tensile stress for the rods material,τ = Permissible shear stress for the cotter material, andσc = Permissible crushing stress for the cotter material.
![Page 4: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/4.jpg)
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1. Failure of the rod(Spigot) in tension
P= Area x Tensile stress
![Page 8: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/8.jpg)
2. Failure of spigot in tension across the weakest section (or slot)
Area Resisting=
P
d2
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3. Failure of the rod (spigot) or cotter in crushing
• P=d2 x t x σc
d2
![Page 10: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/10.jpg)
9. Failure of spigot collar in crushing
![Page 11: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/11.jpg)
8. Failure of rod(Spigot) end in shear
![Page 12: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/12.jpg)
10. Failure of the spigot collar in shearing
![Page 13: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/13.jpg)
4. Failure of the socket in tension across the slot
Area Resisting=
Load P=
.
![Page 14: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/14.jpg)
6. Failure of the socket collar in crushing
![Page 15: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/15.jpg)
7. Failure of socket end in shearing
![Page 16: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/16.jpg)
5. Failure of cotter in shear
![Page 17: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/17.jpg)
Problem 1Design and draw a cotter joint to support a load varying
from 30 kN in compression to 30 kN in tension. The material used is carbon steel for which the following allowable stresses may be used. The load is applied statically. Tensile stress = compressive stress = 50 Mpa shear stress = 35 MPa crushing stress= 90 MPa.
t = Thickness of cotter. It may be taken as d2/4.
The length of cotter ( l ) is taken as 4 d.
![Page 18: Cotter joint pptx](https://reader033.fdocuments.in/reader033/viewer/2022061402/587170f31a28ab58758b780f/html5/thumbnails/18.jpg)
Problem 2Design a cotter joint to transmit a load of 90 kN in
tension or compression. Assume the following stresses for socket, spigot and cotter.
Allowable tensile stress = 90 MpaAllowable crushing stress = 120 MpaAllowable shear stress = 60 Mpa.
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Problem 3
Two rod ends of a pump are joined by means of a cotter and spigot and socket at the ends. Design the joint for an axial load of 100 kN which alternately changes from tensile to compressive. The allowable stresses for the material used are 50 MPa in tension, 40 MPa in shear and 100 MPa in crushing