A brake band attached to the hinge by means of a riveted joint is shown in Fig. 8.59. Determine the size of the rivets needed for the load of 10 kN. Also, determine the width of the band. The permissible stresses for the band and rivets in tension, shear and compression are 80, 60 and 120 N/mm² respectively. Assume,
margin (m) = 1.5d
transverse pitch $\left(p_{t}\right)$ = p
Find the pitch of the rivets.

Question

A brake band attached to the hinge by means of a riveted joint is shown in Fig. 8.59. Determine the size of the rivets needed for the load of 10 kN. Also, determine the width of the band. The permissible stresses for the band and rivets in tension, shear and compression are 80, 60 and 120 N/mm² respectively. Assume,
margin (m) = 1.5d
transverse pitch [latex] \left(p_{t}\right)[/latex] = p
Find the pitch of the rivets.

Accepted Answer

[latex] ext { Given } P=10 kN \quad t=3 mm \quad \sigma_{t}=80 N / mm ^{2} [/latex].

[latex] au=60 N / mm ^{2} \quad \sigma_{c}=120 N / mm ^{2} [/latex].

Step I Diameter of rivets
There are four rivets in the lap joint, which are subjected to single shear. From shear consideration.

[latex] 4\left[\frac{\pi}{4} d^{2} au ight]=P \quad ext { or } \quad 4\left[\frac{\pi}{4} d^{2}(60) ight]=10 imes 10^{3} [/latex].

∴ d = 7.28 or 8 mm (a).

From crushing consideration,

[latex] 4 d t \sigma_{c}=P ext { or } 4 d(3)(120)=10 imes 10^{3} [/latex].

∴ d = 6.94 or 7 mm (b).

From (a) and (b), it is observed that shearing becomes the criterion of design. Therefore,
d = 8 mm
Step II Width of band
Considering tensile strength of plate along the section XX,

[latex] (w-2 d) t \sigma_{t}=P \quad ext { or } [/latex]

[latex] (w-2 imes 8)(3)(80)=10 imes 10^{3} [/latex].

∴ w = 57.67 or 60 mm
Step III Pitch of rivets

m = 1.5d = 1.5(8) = 12 or 15 mm
p + 2m = w or p + 2(15) = 60
p = 30 mm

[latex] p_{t}=p=30 mm [/latex].

Question 8.18: A brake band attached to the hinge by means of a riveted joi...

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