Allen bolts are
Self locking bolts
Designed for shock load
Used in aircraft application
Provided with hexagonal depression in head
Correct Answer :
D. Provided with hexagonal depression in head
Related Questions
The spring mostly used in gramophones is
Helical spring
Conical spring
Flat spiral spring
Volute spring
Stress concentration is caused due to
Variation in properties of material from point to point in a member
Pitting at points or areas at which loads on a member are applied
Abrupt change of section
All of the above
A circular shaft can transmit a torque of 5 kN-m. If the torque is reduced to 4 kN-m, then the maximum value of bending moment that can be applied to the shaft is
1 kN-m
2 kN-m
3 kN-m
4 kN-m
In a horizontal flat belt drive, it is customary to use
Bottom side of belt as slack side
Top side of belt as slack side
Idler pulley
None of the above
According to I.B.R., the efficiency of a double riveted butt joint with double cover straps of equal width should be
45 to 60 %
63 to 70 %
70 to 83 %
80 to 90 %
If a bearing is designated by the number 305, it means that the bearing is of
Medium series whose bore is 5 mm
Medium series whose bore is 25 mm
Light series whose bore is 25 mm
Light series whose bore is 5 mm
The bending moment M and a torque T is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then M is equal to
T/2
T
2T
4T
The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kt as
(Kf + 1)/ (Kt + 1)
(Kf - 1)/ (Kt - 1)
(Kt + 1)/ (Kf + 1)
(Kt - 1)/ (Kf - 1)
The steel pulleys are __________ in weight than cast iron pulleys of the same capacity.
Heavier
Lighter
Moderate
None of these
A sliding bearing which operates without any lubricant present, is called
Zero film bearing
Boundary lubricated bearing
Hydrodynamic lubricated bearing
Hydrostatic lubricated bearing
The velocity factor for very accurately cut and ground metallic gears operating at velocities upto __________ are equal to 6/(6 + v).
10 m/s
12.5 m/s
15 m/s
20 m/s
A bolt of uniform strength can be developed by
Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
Keeping the core diameter smaller than the diameter of the unthreaded portion
Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
None of the above
The number of slots in a 25 mm castle nut is
8
6
4
2
For a shaft diameter of 100 mm, the number of bolts in a flange coupling should be
4
6
8
10
If a load W is applied instantaneously on a bar; Then the stress induced in bar will
Be independent of ratio of mass of load W to mass of bar (y)
Increase with increase in y
Decrease with decrease in y
Depend on other considerations
If the centre distance of the mating gears having involute teeth is varied within limits, the velocity ratio.
Increases
Decreases
Remains unchanged
None of these
A sliding bearing in which although lubricant is present, the working surfaces __________ contact each other at least part of the time, is called boundary lubricated bearing.
Partially
Fully
Either A or B
None of these
The permissible stress in the fillet weld is 100 N/mm². The fillet weld has equal leg lengths of 15 mm each. The allowable shearing load on the weldment per cm length of the weld is
7.5 kN
10.6 kN
15 kN
22.5 kN
Cold working
Increases the fatigue strength
Decreases the fatigue strength
Has no influence on fatigue strength
Alone has no influence on fatigue strength
When the belt speed increases
Power transmitted increases
Power transmitted decreases
Power transmitted increases to a maximum value and then decreases
Power transmitted remains the same
The ball bearings are provided with a cage
To reduce friction
To facilitate slipping of balls
To prevent the lubricant from flowing out
To maintain the balls at a fixed distance apart
Spring index is
Ratio of coil diameter to wire diameter
Load required to produce unit deflection
Its capability of storing energy
Indication of quality of spring
Factor of safety for fatigue loading is the ratio of
Elastic limit to the working stress
Elastic limit to the yield point
Endurance limit to the working stress
Young's modulus to the ultimate tensile strength
The allowable static stress for steel gears is approximately __________ of the ultimate tensile stress.
One-fourth
One-third
One-half
Double
In leaf springs, the longest leaf is known as
Master leaf
Lower leaf
Upper leaf
None of these
When an open coiled helical compression spring is subjected to an axial compressive load, the maximum shear stress induced in the wire is (where D = Mean diameter of the spring coil, d = Diameter of the spring wire, K = Wahl's stress factor, and W = Axial compressive load on the spring)
(WD/ πd3) × K
(2WD/ πd3) × K
(4WD/ πd3) × K
(8WD/ πd3) × K
A compound cylinder with inner radius 50 mm and outer radius 70 mm is made by shrinking one cylinder on to the other cylinder, the junction radius is 60 mm and the junction pressure is 1.1 N/mm². The maximum hoop stress developed in the inner cylinder is
3.6 N/mm² compression
3.6 N/mm² tension
7.2 N/mm² compression
7.2 N/mm² tension
In second type of levers,
Load is in between the fulcrum and effort
Effort is in between the fulcrum and load
Fulcrum is in between the load and effort
None of these
The rolling contact bearings as compared to sliding contact bearings have
Low starting and low running friction except at very high speeds
Accuracy of shaft alignment
Small overall dimensions
All of the above
Two shafts A and B under pure torsion are of identical length and identical weight and are made of the same material. The shaft A is solid and the shaft B is hollow. We can say that
Shaft B is better than shaft A
Shaft A is better than shaft B
Both the shafts are equally good
None of these