Machine Drawing

Screwed Fasteners 97

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d:\N-Design\Des5-1.pm5 Seventh Print

In this arrangement, a set screw fitted through the cap and through the bolt end, prevents

the loosening tendency of the nut, when the pitches of the main nut and the set screw are

different (Fig. 5.33). This type of arrangement is used for fitting the propeller blades on

turbine shafts.

SCREW,

DIA 0.25 D

0.25 D

0.25 D

0.2 D

2D

0.9 D

D

1.5 D

1.35 D

D

2.25 D

0.3 D

0.15 D

0.4 D

0.9 D

SCREW, DIA 0.25 D

LONG 0.85 D

2D

1.5 D

1.2 D

Fig. 5.32 Grooved nut Fig. 5.33 Locking by screw

5.10.8 Locking by Plate

A locking plate is grooved such that it fits a hexagonal nut in any position, at intervals of

30° of rotation. It is fixed around the nut, by means of a machine screw, as shown in Fig.

5.34.

5.10.9 Locking by Spring Washer

In this arrangement, a spring washer of either single or double coil is placed under the nut

and tightened. The spring force of the washer will be acting upwards on the nut. This force

makes the threads in the nut jammed on the bolt threads; thus preventing the nut from

loosening (Fig. 5.35).