368 Machine Drawing
dharm
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
