# MCQs on Clamp Coupling & Rigid Flange & Coupling Bushed Pin Flexible Coupling

1 - Question

Clamp coupling employ bolts.

a) True
b) False

Explanation: The two halves of sleeve are clamped together by bolts.

2 - Question

Entire torque is transmitted by friction in the clamp coupling.

a) True
b) False

Explanation: Some torque is transferred by friction and some by key.

3 - Question

Does shaft has to be shifted i axial direction to remove clamp coupling.

a) Yes
b) No

Explanation: Clamp coupling unlike muff coupling is easily removed without shifting the shaft in axial direction.

4 - Question

If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling.

a) 100mm
b) 80mm
c) 60mm
d) 40mm

Explanation: Dia=2.5d.

5 - Question

If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling.

a) 80mm
b) 140mm
c) 100mm
d) 120mm

Explanation: L=3.5d.

6 - Question

If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m.

a) 51234.4N
b) 45968.3N
c) 41666.7N
d) None of the listed

Explanation: P=2M/fdn.

7 - Question

If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm².

a) 27mm
b) 25mm
c) 23mm
d) 21mm

Explanation: Ax80=2M/fdn.

8 - Question

Power is transmitted by only in rigid flange coupling.

a) True
b) False

Explanation: Power is transmitted by key as well as bolts.

9 - Question

If shaft diameter is 60mm, how many bolts are recommended for rigid flange coupling?

a) 2
b) 3
c) 4
d) 5

Explanation: If shaft diameter is between 40mm and 100mm, 4 bolts are used.

10 - Question

Determine the diameter of the bolts used in rigid flange coupling if transmitted torque is 270N-m, pitch circle diameter=125mm and four bolts are emplace in the coupling. Permissible shear stress in the bolts is 70N/mm².

a) 3.8mm
b) 3.6mm
c) 4.4mm
d) 4mm

Explanation: d²=8M/πDNτ.

11 - Question

The hub is treated as a solid shaft while calculating torsional shear stress in the hub.

a) True
b) False

Explanation: Hub is treated as a hollow shaft.

12 - Question

Find the shear stress in a flange at the junction of hub in rigid flanged coupling if torsional moment is 2980N-m and diameter of hub being 125mm. Also the thickness of flange is 25mm.

a) 6.77N/mm²
b) 10.24N/mm²
c) 4.84N/mm²
d) 4.22N/mm²

Explanation: τ=2M/πd²t.

13 - Question

If shaft diameter is 30mm and number of pins emplaced are 6, then the diameter of the pin will be?

a) 6.4mm
b) 5.6mm
c) 6.1mm
d) 5.9mm

Explanation: d₁=.5d/√N.

14 - Question

Calculate the force acting on the each pin in flexible coupling if torque transmitted is 397N-m and PCD=120mm with number of pins 6.

a) 1400.3N
b) 1102.8N
c) 1320.3N
d) None of the listed