Page 121 - Analysis and Design of Machine Elements

Problems Detachable Fastenings for Shaft and Hub 99

Review Questions

1 Explain how parallel keys and taper keys work.

2 What are the potential failure modes of parallel keys?

3 What measure should be taken if a key does not have sufficient strength?

Objective Questions

1 The dimension of the cross section of a key is selected by ________.
(a) the transmitted torque
(b) the transmitted power
(c) the length of the wheel hub
(d) the diameter of the mating shaft

2 The length of a key is selected by ___________.
(a) the transmitted torque
(b) the transmitted power
(c) the length of the wheel hub
(d) the diameter of the mating shaft

3 Which of the following is a taper key in Figure P4.1? ___________.

(a) (b) (c) (d)
Figure P4.1 Illustration for Objective Questions 3 and 4.

4 Which represents a parallel key in Figure P4.1? ___________

5 A parallel key is supposed to transmit a maximum torque of T in Figure P4.2. If a
torque of 1.5 T is to be transmitted, it is better to ______.