Spur gears can be used only when the two shafts are parallel.

Consider the following statements: 1. In spur gears, the contact occurs abruptly on a line parallel to the axis, and the disengagement too is abrupt. 2. In helical gears, both loading and unloading are gradual, and therefore, these happen more smoothly and less noisily 3. When two gears mesh, any arbitrary shape of the tooth can be chosen for the profile of the teeth of any one of the two gears, and the profile for the other shall be obtained by applying the law of gearing. Which of the above statements are correct?

A

1 and 2 only

B

1 and 3 only

C

2 and 3 only

D

1, 2 and 3

Consider two shafts connected with two gears as per the following options: 1. One on each shaft 2. Through an intermediate gear mounted on an intermediate shaft, and every shaft having one gear only 3. Through an intermediate gear mounted on an intermediate shaft, with the intermediate shaft having two gears, whereas the other shafts have one gear each Which of the above represent(s) a simple gear train?

A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2 and 3

Tapered involute gears which can couple intersecting shafts, skew shafts, and parallel shafts are known as

A

bevel gears

B

beveloid gears

C

mitre gears

D

none of the mentioned

Statement (I): Two non-intersecting and non-parallel, i.e., non-coplanar, shafts connected by gears are called skew-bevel gears or spiral gears, and this type of gearing has a line contact the rotation of which about the axes generates the two hyperboloid pitch surfaces. Statement (II): A hyperboloid is a 3D surface formed by revolving a straight line about an axis (not in the same plane), such that every point on the line remains at a constant distance from the axis.

A

Both Statement I) and Statement II) are individually true and Statement II) is the correct explanation of Statement I)

B

Both Statement I) and Statement II) are individually true but Statement II) is not the correct explanation of Statement I)

C

Statement I) is true but Statement II) is false

D

Statement I) is false but Statement II) is true

Hollow shafts can be made as strong as solid shafts by making the twisting moments of both the shafts same. Shafts made by __________ have residual stresses.

A

Forging

B

Cold rolling

C

Hot rolling

D

Casting

Among the following types of gears, which gears offer a refinement over spur gears?

A

Skew Gear

B

Advanced spur gears

C

External Gears

D

Helical Gears

Helical gears mounted on parallel shafts are called crossed helical gears.

A

True

B

False

Spur gears can transmit power between perpendicular shafts.

A

True

B

False

For an Oldham coupling used between two shafts, which among the following statements are correct? I. Torsional load is transferred along shaft axis. II. A velocity ratio of 1:2 between shafts is obtained without using gears. III. Bending load is transferred transverse to shaft axis. IV. Rotation is transferred along shaft axis.

A

I and III

B

I and IV

C

II and III

D

II and IV

Two advantages of using helical gears rather than spur gears in a transmission system are

A

Strength and cost

B

Strength and less end thrust

C

Noise level and strength

D

Noise level and economy

Spur gears can be used only when the two shafts are parallel.

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