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Differentiate between Involute and cycloidal gear tooth profile
Sketch and explain reverted gear train with suitable example
A flat belt drives a pulley, the angle of lap being 1200. The belt is 100mm wide and 6mm thick. The
density of belt material is 1000kg/m3. If the coefficient of friction and maximum stress in the belt should
not exceed 2MPa. Find the maximum power transmitted and corresponding speed of the belt.
Derive the equation for the tension ratio for the flat belt drive.
Classify gears and gear trains with neat sketch and explain the law of gearing.
Two gear wheels mesh externally and are to give a velocity ratio of 3:1. The teeth are of involute form;
module =5mm, addesndum = one module, pressure angle =200. The pinion rotates at 150 r.p.m.
Determine 1. The number of teeth on the wheel, 2. The length of path and arc of contact, 3. The
maximum velocity of sliding.
Classify cams and follower and explain cam terminology.
A cam is rotating at 300rpm operate a reciprocating knife edge follower. The least radius of the cam
25mm, stroke of the follower is 35mm. Ascent ad descent by simple harmonic motion. Ascent takes
place by 600and descent during 450of the cam rotation. Dwell between ascent and descent 300. Sketch
velocity and acceleration diagram. State the nature of the curves and show the maximum values of
velocity and acceleration.
With neat sketch explain Undercutting in CAMS
Explain slip and creep in belt drives
In an open belt drive, the diameters of the larger and smaller pulley are 1.2 m and
0.8 m respectively. The smaller pulley rotates at 320 rpm. The center distance
between the shafts is 4 m. When stationary, the initial tension on the belt is 2.8
kN. The mass of belt is 1.8 kg/m and the coefficient of friction between the belt
and pulley is 0.25. Determine the power transmitted
Fig. shows a reverted epicyclic gear train, the arm A carries two gears B and C
and a compound gear D – E. The gear B meshes with gear E and the gear C
meshes with gear D. The number of teeth on gears B, C and D are 75, 30 and 90
respectively. Find the speed and direction of gear C when gear B is fixed, and the
arm A makes 100 rpm. clockwise
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Illustrate with neat sketch band brake and state its applications
Explain the concept of centrifugal tension and sate its effect on power
transmission?
The number of teeth on each of the two equal spur gears in mesh is 50. The teeth
have 20involute profile and the module is 6 mm. If the arc of contact is 1.65
times the circular pitch. Find the addendum
A cam is rotating at 200 rpm operate a reciprocating roller follower of radius 2.5
cm. The least radius of cam is 30 mm, stroke of follower is 5 cm. Ascent takes
place by uniform acceleration and deceleration and descent by simple harmonic
motion. Ascent takes place by 70and descent during 50of cam rotation. Dwell
between ascent and descent 60 . Sketch displacement, velocity, acceleration,
diagram. Indicate the maximum values of velocity and acceleration and state the
nature of curve
State any Five CAM terminology
Classify various types of brakes
A leather belt is required to transmit 7.5 kW from a pulley 1.2 m in diameter running at
250 r.p.m. The angle embraced is 165° and the coefficient of friction between the belt and the
pulley is 0.3. If the safe working stress for the leather belt is 1.5 MPa, density of leather 1
Mg/m3 and thickness of belt 10 mm, determine the width of the belt taking centrifugal tension
into account.
A roller follower is operated by a uniform rotating cam. The follower is raised
through a distance of 25 mm in 120⁰ rotation of the cam, remains at rest for next 30⁰ and is
lowered during further 120⁰ rotation of the cam. The raising of the follower takes place with
cycloidal motion and the lowering with uniform acceleration and deceleration. The least
radius of the cam is 25 mm which rotates at 300 rpm. Plot displacement, velocity and
acceleration curves and find the values of the maximum velocity and maximum acceleration
during rising and return stroke of the follower.
Classify various types of chains with suitable examples
Two shafts A and B are co-axial. A gear C (50 teeth) is rigidly mounted on shaft A. A
compound gear D-E gears with C and an internal gear G. D has 20 teeth and gears with C and
E has 35 teeth and gears with an internal gear G. The gear G is fixed and is concentric with
the shaft axis. The compound gear D-E is mounted on a pin which projects from an arm
keyed to the shaft B. Sketch the arrangement and find the number of teeth on internal gear G
assuming that all gears have the same module. If the shaft A rotates at 110 rpm., find the
speed of shaft B.
Derive the equation for centrifugal tension.
