Machine Drawing

(avery) #1

368 Machine Drawing


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d:\N-Design\Des19-1.pm5


(^152)
U/C WIDE 5
DEEP 2
f 32
f 36
f 50


120

1

R145

16

76

f 100

4

3

5

13 12

96

8

615

f 28

M22

12

f 15
18
R145

106146

f 51
f 62

9

SERRATED

Part No. Name Matl. Qty.
1
2
3
4
5

Body
Clamp screw
Wedge
Ring
Square block

MS

MCS

CI

MS

MS

1

1

1

1

1

Parts list

Fig. 19.8 Single tool post

19.3.3 Lathe Speed Gear Box


In a conventional engine lathe, different spindle speeds are obtained by means of belt driven cone


pulley and back gear arrangement. The step cone pulley and the back gear are accommodated in


the headstock of the engine lathe. This arrangement suffers from (i) slipping of the belt, (ii)


change of speed, requiring change of belt position and (iii) lack of positive drive. To overcome these


draw backs and to provide a positive drive, the belt drive is replaced by a gear drive. A lathe with


speed gear box is known as an all geared lathe. The assembly drawing of an all geared lathe


headstock is shown in Fig. 19.10(a). It may be noted that, for the purpose of clarity of the drive


mechanism, the shafts are shown as if they are one below the other and in the same plane.


The drive shaft S2 is positioned in the head stock body 1 of the lathe and is driven by an


electric motor through a belt drive, using a V-pulley 5. The headstock also contains an intermediate


splined shaft S3, on which sliding gears are mounted. Further, spindle S4 is also positioned in the


head stock on which work holding devices such as self centering chuck, etc., are attached. The


spindle is mounted on the taper roller bearings 6 and 7, which resist both axial thrust as well as


transverse or radial force coming on the spindle. The drive shaft and the intermediate shafts are


mounted on the ball bearings 8, 9 and 10. These bearings are protected by means of the cover

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