Chapter 18: Brakes and Clutches

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Chapter 18 Brakes and Clutches
Nothing has such power to broaden the mind as the
ability to investigate systematically and truly
all that comes under thy observation in
life. Marcus Aurelius, Roman Emperor
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Brake and Clutch Types
Figure 18.1 Five types of brake and clutch. (a)
internal, expanding rim type (b) external
contracting rim type (c) band brake (d) thrust
disk (e) cone disk.
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Thrust Disk
Figure 18.2 Thrust disk clutch surface with
various radii.
Figure 18.3 Effect of radius ratio on
dimensionless torque for uniform pressure and
uniform wear models.
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Properties of Common Friction Materials
Table 18.1 Representative properties of
contacting materials operating dry.
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Friction for Wet Clutch Materials
Table 18.2 Coefficient of friction for
contacting materials operating in oil.
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Cone Clutch
Figure 18.4 Forces acting on elements of cone
clutch.
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Short-Shoe Brake
Figure 18.5 Block, or short-shoe brake, with two
configurations.
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Example 18.3
Figure 18.6 Short-shoe brake used in Example
18.3.
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Long-Shoe, Internal Expanding Rim Brake
Figure 18.7 Long-shoe, internal, expanding rim
brake with two shoes.
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Forces and Dimensions
Figure 18.8 Forces and dimensions of long-shoe,
internal, expanding rim brake.
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Example 18.4
Figure 18.9 Four-long-shoe, internal expanding
rim brakes used in Example 18.4.
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Long-Shoe, External, Contracting Rim Brake
Figure 18.10 Forces and dimensions of long-shoe,
external, contracting rim brake.
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Pivot-Shoe Brake
Figure 18.11 Symmetrically loaded pivot-shoe
brake.
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Band Brake
Figure 18.12 Band brake. (a) Forces acting on
band (b) forces acting on element.
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Example 18.7
Figure 18.13 Band brake used in Example 18.7.
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Capacities of Brake and Clutch Materials
Table 18.3 Product of contact pressure and
sliding velocity for brakes and clutches.
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Hydraulic Crane Brake Case Study
Figure 18.14 Hoist line brake for mobile
hydraulic crane. The cross-section of brake with
relevant dimensions is given.