Which of the following screw thread is used for power transmission in one direction only?
Square threads
Multiple threads
Acme threads
Buttress threads
Correct Answer :
D. Buttress threads
Related Questions
Which of the following coupling is used to connect two shafts which have both lateral and angular misalignment?
Bushed pin type coupling
Universal coupling
Oldham coupling
All of these
The product of the diametral pitch and circular pitch is equal to
1
1/π
π
π × number of teeth
The stress induced in the belt is,
Tensile stress
Compressive stress
Direct shear stress
Torsional shear stress
Which is positive drive?
Flat belt drive
V-belt drive
Crossed belt drive
Timing belt
For general industrial machinery, the ratio of the length of journal to its diameter is taken as
0.5 to 1
1 to 2
3 to 5
5 to 10
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
Three different weights fall from a certain height under vacuum. They will take
Same time to reach earth
Times proportional to weight to reach earth
Times inversely proportional to weight to reach earth
None of the above
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
In case of pressure vessels having closed ends, the fluid pressure induces
Longitudinal stress
Shear stress
Circumferential stress
None of these
Machine 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 two parts
Similar to stud
When an open coiled helical compression spring is subjected to an axial compressive load, the stress induced in the wire is
Tensile stress
Compressive stress
Shear stress
Bending stress
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
In order to permit the thermal expansion/contraction of tubing, it should be
Crimped
Honed
Flared
Bent
A leaf spring in automobiles is used
To apply forces
To measure forces
To absorb shocks
To store strain energy
A tapered key which fits in a key way in the hub and the bottom of which is shaped to fit the curved surface of the shaft, is known as,
Hollow saddle key
Hollow key
Soft key
None of these
The maximum efficiency of a square threaded screw is
(1 - sinφ)/ (1 + sinφ)
(1 + sinφ)/ (1 - sinφ)
(1 - sinφ)/ (1 + cosφ)
(1 + cosφ)/ (1 - sinφ)
According to I.B.R., the distance between the rows of rivets, for equal number of rivets in more than one row for lap joint or butt joint (chain riveting) shall not be less than
d
1.5 d
2d
2.5 d
Fabric belts are used in industrial applications because
They are cheap
They can work at high temperature
They are unaffected by moisture and humidity
None of the above
In a steam engine, the piston rod is usually connected to the crosshead by means of a
Knuckle joint
Cotter joint
Oldham coupling
Universal joint
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
The velocity factor for precision metallic gears cut with high accuracy and operating at velocities upto 20 m/s is equal to
0.75/ (0.75 + √v)
3/ (3 + v)
4.5/ (4.5 + v)
6/ (6 + v)
For standard coarse threads of nut, the threads will be as strong in failure by shear as the bolt in tension, if the height of nut (h) is approximately
0.4 times
0.6 times
0.7 times
0.8 times
In V-belt drive, belt touches
At bottom
At sides only
Both at bottom and sides
Could touch anywhere
For maximum power, the velocity of the belt will be
√(T/m)
√(T/2m)
√(T/3m)
None of these
The largest diameter of an external or internal screw thread is known as
Minor diameter
Major diameter
Pitch diameter
None of these
The most important dimension in the design of a nut is
Pitch diameter
Inside diameter
Outside diameter
Height
Multiple threads are used to secure
Low efficiency
High efficiency
High load lifting capacity
High mechanical advantage
In oilness bearings
The oil film pressure is generated only by the rotation of the journal
The oil film is maintained by supplying oil under pressure
Do not require external supply of lubricant
Grease required to be applied after some intervals
The stretching in a belt can be controlled by __________ the stress in the belt.
Reducing
Increasing
Both A and B
None of these
If a spring is cut down into two springs, the stiffness of cut springs will be
Half
Same
Double
None of the above