Mechanical Components-II

Front

What is the purpose of a chain puller?

Back

It brings the two ends of a chain together so they can be easily joined.

Answer explanation

A chain puller is a specialized tool used in mechanical and industrial settings where chains are used for power transmission or lifting. When installing or repairing a chain, it can be difficult to bring the two ends of the chain together, especially if the chain is under tension or in a tight space. The chain puller is designed to grip both ends of the chain and pull them together, making it much easier to connect the ends and install a master link or connector. This tool helps ensure a secure and proper connection, improving safety and efficiency during chain installation or maintenance.

Front

Which style of hub on a sprocket has the least need for a keyway? Options: Hybrid, Bushing, Single, Double

Back

Bushing

Front

A fractional hp V-belt drive is intended for:

Back

light-duty application.

Front

Which image depicts a sprocket with a taper lock bushing hub? Options: [A], [B], [C], [D]

Back

[C]

Front

How can chain sag be determined? Options: Pinch the feed and return the sides of the chain, then measure the distance between the links. Rotate the drive sprocket forward and measure the deflection on the slack side of the chain. Remove the chain and make sure it is loose as long as the distance between sprockets. Rotate the drive sprocket forward and measure the deflection on the tight side of the chain.

Back

Rotate the drive sprocket forward and measure the deflection on the slack side of the chain.

Answer explanation

Chain sag refers to the amount of slack or looseness in a chain drive system, such as those found in bicycles or motorcycles. To accurately measure chain sag, you should rotate the drive sprocket forward to ensure the chain is properly tensioned, then measure the vertical deflection (movement) on the slack side of the chain. This method ensures you are measuring the actual slack and not the tensioned portion of the chain. Measuring on the tight side or pinching the chain does not provide an accurate assessment of sag.

Front

Find the driver-to-driven gear ratio.

Back

9:1

Answer explanation

In the diagram, the driver gear has 10 teeth, the middle gear has 30 teeth, and the final driven gear has 90 teeth. The gear ratio is calculated by dividing the number of teeth on the driven gear by the number of teeth on the driver gear.

Gear ratio = (Teeth on driven gear) / (Teeth on driver gear) = 90 / 10 = 9:1.

Therefore, the driver-to-driven gear ratio is 9:1.

Front

Which cam profile specifies the dwell period(s)? Options: T1, T2, T4, T2, T1, T3

Back

T2, T4

Answer explanation

In a cam displacement diagram, the dwell period is the interval during which the follower remains stationary (displacement is constant). In the given diagram, the horizontal segments (T2 and T4) represent periods where the displacement does not change, indicating dwell periods. Therefore, the cam profile specifies the dwell periods at T2 and T4.

Front

Which method is used to allow for the effect of thermal expansion of mechanical couplings used on motor drives? Options: Brass shims around the shafts, Felt padding glued to the shafts, Small gaps between shaft faces, Coolant fluids dripped on the components

Back

Small gaps between shaft faces

Answer explanation

When mechanical couplings are used to connect motor drives, the shafts and couplings can expand or contract due to temperature changes during operation. If there is no allowance for this thermal expansion, it can lead to excessive stress, misalignment, or even damage to the components. The most common and effective method to accommodate this expansion is to leave small gaps between the faces of the shafts. These gaps provide the necessary space for the shafts to expand without causing interference or stress, ensuring smooth operation and longevity of the mechanical system.

Front

A driver sprocket has 30 teeth, and a driven sprocket has 90 teeth. What torque is applied to the driven shaft if the input torque is 60 in-lb?

Back

180 in-lb

Answer explanation

The torque ratio in a sprocket system is equal to the ratio of the number of teeth on the driven sprocket to the number of teeth on the driver sprocket.
Torque on driven shaft = Input torque × (Teeth on driven sprocket / Teeth on driver sprocket)
Torque on driven shaft = 60 in-lb × (90 / 30) = 60 in-lb × 3 = 180 in-lb.

Front

What is the function that the slots perform in an electric motor mount plate?

Back

Provide an adjustment for component tension

Answer explanation

The slots in an electric motor mount plate are designed to allow for the adjustment of the motor's position. This is crucial for setting the correct tension on the drive belt or chain that connects the motor to the driven equipment. By loosening the mounting bolts, the motor can be slid along the slots to either increase or decrease the tension as needed, ensuring optimal performance and reducing wear on the components. This adjustability is especially important in systems where belt or chain tension can change over time due to stretching or settling.