If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation
124 d
138 d
151 d
168 d
Correct Answer :
D. 168 d
Related Questions
Screws used for power transmission should have
Low efficiency
High efficiency
Very fine threads
Strong teeth
For same pulley diameters, center distance, belt speed and belt and pulley materials,
Open belt drive transmits more power than crossed belt drive
Crossed belt drive transmits more power than open belt drive
Open and crossed belt drives transmit same power
Power transmission does not depend upon open and crossed types of constructions
Which of the following pipe joints would be suitable for pipes carrying steam?
Flanged
Threaded
Bell and spigot
Expansion
A triple riveted butt joint with double straps of unequal width is to be designed for a boiler shell. The pitch of the rivets in the outer row is double the pitch in the inner row and zigzag riveting is proposed. Which of the following statement is correct?
There are four rivets per pitch length, all in double shear
There are four rivets per pitch length, out of which two are in single shear and two are in double shear
There are five rivets per pitch length, all in double shear
There are five rivets per pitch length, out of which four are in double shear and one is in single shear
The property of a material which enables it to resist fracture due to high impact loads is known as
Elasticity
Endurance
Strength
Toughness
In worm gears, the angle between the tangent to the pitch helix and an element of the cylinder, is known as
Helix angle
Pressure angle
Pitch lead angle
None of these
A key capable of tilting in a recess milled out in a shaft is known as
Woodruff key
Feather key
Flat saddle key
Hollow saddle key
In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called
Normal pitch
Axial pitch
Diametral pitch
Module
The period during which the cam follower remains at rest, when cam moves, is known as
Constant period
Fixed period
Dwell period
Idle period
The elasticity is the property of a material which enables it to
Regains its original shape after deformation when the external forces are removed
Draw into wires by the application of a tensile force
Resists fracture due to high impact loads
Retain deformation produced under load permanently
Which of the following statement is correct?
The distance from a point on one thread to the corresponding point on the next thread is called pitch
The distance which a screw thread advances axially in one rotation of the nut is called lead
In single start threads, lead is equal to pitch
All of the above
Resilience of a material is important, when it is subjected to
Combined loading
Fatigue
Thermal stresses
Shock loading
When a beam of rectangular cross-section of width b and depth d, is subjected to a shear force F, the maximum shear stress induced will be
F/bh
3F/2bh
2F/bh
4F/bh
When the belt is transmitting maximum power, the belt speed should be
√(Pmax / 2m)
√(Pmax / 3m)
√(Pmax / m)
√(3m /Pmax) Where m = mass of belt per metre (kg/m) Pmax = maximum permissible tension in belt (N)
Cap screws are
Similar to small size tap bolts except that a greater variety of shapes of heads are available
Slotted for a screw driver and generally used with a nut
Used to prevent relative motion between parts
Provided with detachable caps
The edges of a boiler plate are bevelled to an angle of
30°
45°
60°
80°
In case of thick cylinders, the tangential stress across the thickness of cylinder is
Maximum at the outer surface and minimum at the inner surface
Maximum at the inner surface and minimum at the outer surface
Maximum at the inner surface and zero at the outer surface
Maximum at the outer surface and zero at the inner surface
Antifriction bearings are
Sleeve bearings
Hydrodynamic bearings
Thin lubricated bearings
None of the above
The efficiency of a riveted joint is equal to
Pt /P
Ps /P
Pc /P
Least of Pt, Ps and Pc/P
If T is the actual number of teeth on a helical gear and φ is the helix angle for the teeth, then formative number of teeth is written as
T sec3φ
T sec²φ
T/sec3φ
T cosecφ
The backlash for spur gears depends upon
Module
Tooth profile
Both module and pitch line velocity
Pitch line velocity
The shock absorbing capacity of a bolt can be increased by
Tightening it properly
Increasing shank diameter
Grinding the shank
Making shank diameter equal to core diameter of thread.
When bevel gears connect two shafts whose axes intersect at an angle greater than a right angle and one of the bevel gears has a pitch angle of 90°, then they are known as
Crown bevel gears
Angular bevel gears
Mitre gears
Internal bevel gears
When the fulcrum is in between the load and effort, the lever is said to be of
First type
Second type
Third type
Any one of these
In case of pressure vessels having closed ends, the fluid pressure induces
Longitudinal stress
Shear stress
Circumferential stress
None of these
The shearing stresses in the inner face as compared to outer face of the wire in a heavy close coiled spring is
Larger
Smaller
Equal
Larger/smaller depending on diameter of spring coil
Which of the following material has the maximum ductility?
Copper
Mild steel
Aluminium
Zinc
When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
2WD3n/Gd⁴
4WD3n/Gd⁴
8WD3n/Gd⁴
16WD3n/Gd⁴
For a shoe brake, the equivalent coefficient of friction is equal to (where μ = Actual coefficient of friction, and θ = Semi-block angle)
2μ sinθ/(θ + sinθ)
μ sinθ/(2θ + sin 2θ)
4μ sinθ/(θ + sinθ)
4μ sinθ/(2θ + sin 2θ)
The crest diameter of a screw thread is same as
Major diameter
Minor diameter
Pitch diameter
Core diameter