The document discusses bushed pin type shaft couplings, including their classification, advantages, and disadvantages, focusing on their ability to tolerate misalignments and absorb vibrations. It details design considerations and provides problems for calculating pin diameters by shear and bending stresses for flexible couplings used in various applications. Reference materials for further information on machine design are also included.

1. SHAFT COUPLINGS – Bushed Pin TypeSHAFT COUPLINGS – Bushed Pin Type
D. Narendra Varma,
Assistant Professor,
Mechanical Engineering Dept.,
Miracle Educational society Group of Institutions.

2. Classification of Shaft couplings

3. Types
Oldham Coupling Hooke’s or Universal coupling

4. Bushed-Pin Flexible Coupling

5. Misalignment
• 0.5mm , 1.5o
Reasons
• Deflection of shafts due to lateral
forces
• Error in shaft mounting due to
manufacturing tolerances
• Use of 2 separately manufactured
units such as electric motor & worm
gear box
• Thermal expansion of the parts
• 0.5mm , 1.5o
Reasons
• Deflection of shafts due to lateral
forces
• Error in shaft mounting due to
manufacturing tolerances
• Use of 2 separately manufactured
units such as electric motor & worm
gear box
• Thermal expansion of the parts

6. Advantages
• Can tolerate misalignments
• Prevents transmission of shock from one shaft to
other and absorbs vibrations
• Can be used for transmitting high torques
• Simple in construction
• Easy to assemble & dismantle
• Easy to design & manufacture
Disadvantages
• Cost is high
• More radial space
• Can tolerate misalignments
• Prevents transmission of shock from one shaft to
other and absorbs vibrations
• Can be used for transmitting high torques
• Simple in construction
• Easy to assemble & dismantle
• Easy to design & manufacture
Disadvantages
• Cost is high
• More radial space

7. Proportions of Bushed-Pin Flexible
Coupling

8. Analysis of Flexible coupling

10. Features of Flexible bush coupling
• Gap between the flanges for compensating the
misalignment
• Flexible bush coupling either has greater no. of
bolts (or pins) than rigid coupling or has larger
bolt circle diameter.
• Gap between the flanges for compensating the
misalignment
• Flexible bush coupling either has greater no. of
bolts (or pins) than rigid coupling or has larger
bolt circle diameter.

11. Design Procedure of Flexible coupling

13. Problem 1
A flexible coupling, illustrated in Fig. 9.39, is used to
transmit 15 kW power at 100 rpm. There are six
pins and their pitch circle diameter is 200 mm. The
effective length of the bush (l), the gap between two
flanges and the length of the pin in contact with the
right hand flange are 35, 5 and 23 mm respectively.
The permissible shear and bending stresses for the
pin are 35 and 152 N/mm2 respectively. Calculate:
(i) pin diameter by shear consideration; and
(ii) pin diameter by bending consideration.
A flexible coupling, illustrated in Fig. 9.39, is used to
transmit 15 kW power at 100 rpm. There are six
pins and their pitch circle diameter is 200 mm. The
effective length of the bush (l), the gap between two
flanges and the length of the pin in contact with the
right hand flange are 35, 5 and 23 mm respectively.
The permissible shear and bending stresses for the
pin are 35 and 152 N/mm2 respectively. Calculate:
(i) pin diameter by shear consideration; and
(ii) pin diameter by bending consideration.

15. Problem 2
It is required to design a bushed-pin type flexible
coupling to connect the output shaft of an
electric motor to the shaft of a centrifugal
pump. The motor delivers 20 kW power at 720
rpm. The starting torque of the motor can be
assumed to be 150% of the rated torque. Design
the coupling and specify the dimensions of its
components.
It is required to design a bushed-pin type flexible
coupling to connect the output shaft of an
electric motor to the shaft of a centrifugal
pump. The motor delivers 20 kW power at 720
rpm. The starting torque of the motor can be
assumed to be 150% of the rated torque. Design
the coupling and specify the dimensions of its
components.

19. Key stresses
Shear -73.68 < 100 N/mm2
Compressive 168.41 < 100
N/mm2

21. References:
1. Machine Design – V.B.Bandari .
2. Machine Design – R.S. Khurmi
3. Design Data hand Book - S MD Jalaludin.
1. Machine Design – V.B.Bandari .
2. Machine Design – R.S. Khurmi
3. Design Data hand Book - S MD Jalaludin.