Split nut is a locking device in which:
a) one smaller nut is tightened over the main nut and the main nut tightened against the smaller one by loosening, creating friction jamming
b) a slot is cut partly in the middle of the nut and then the slot reduced by tightening the screw
c) a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip
d) through slots are made at the top and a cotter-pin is passed through these and a hole in the bolt, and the cotter pin is split and bent in the reverse direction at the other end e) none of the above.
The correct answer and explanation is:
The correct answer is a) one smaller nut is tightened over the main nut and the main nut tightened against the smaller one by loosening, creating friction jamming.
A split nut, also known as a lock nut, is designed to prevent loosening due to vibrations or torque. In this case, the mechanism involves using two nuts: one main nut and one smaller nut. The smaller nut is tightened over the main nut, creating a situation where the main nut is tightened against the smaller nut, causing friction between the two. This friction makes it difficult for the main nut to rotate, which effectively locks it in place.
The locking action occurs when the smaller nut is tightened around the main nut. As the main nut is tightened, it presses against the smaller nut, and the friction generated prevents the main nut from loosening. This locking feature is especially useful in environments where vibrations or dynamic loads are present, as it helps maintain the integrity of the fastening system.
In contrast, other options provided describe different types of locking devices but not the split nut mechanism. For example, option b, which talks about a slot being cut in the middle of the nut and then reduced by tightening, sounds more like a form of lock washer or a different mechanical fastening system. Option c mentions the use of fiber or nylon cotter, which describes another form of locking mechanism. Option d, which discusses a cotter pin, is typical of a split pin or cotter pin used in bolted connections, but this is not a description of a split nut.
Therefore, option a is the correct choice, as it specifically refers to the type of locking mechanism used in a split nut, which works by generating friction between the main nut and a smaller nut.