Technical Information · issue 40 of 1994
Friction clutch
Model E 20 Electric Chain Saws - Series 1207
IssueTI 40/1994
From serial 31 010 462
Part changes (1)
| Was | Becomes | What the bulletin says |
|---|---|---|
| 1207 967 1500 | 1207 967 1501 | The original aluminium nameplates 1207 967 1500/05 will be replaced by the new clip-in plastic versions 1207 967 1501/02. |
Full text
Page 1 of 3
Technical Information
40.94
Model E 20 Electric Chain Saws - Series 1207
Contents
1. Friction clutch (between gear drive
and chain sprocket)
2. Nameplate (clip-in plastic nameplate)
1. Friction clutch
A friction clutch will be installed in the STIHL E 20
from machine number X 31 010 462.
5
1.1 Purpose
The new fricton clutch considerably reduces the 8
mechanical load on the ring gear.
The teeth on the gearwheel (ring gear) are no longer
sheared off by the use of excessive infeed force or 7
contact with metal (e.g. nails, etc.).
4
This helps extend the wear life of the gearwheel
(ring gear) by a factor of 5 to 8.
Jolts which were previously transmitted to the 7
machine from the chain and gearwheel are now
absorbed by the new friction clutch. The motor is
no longer locked up. This helps enhance operator
comfort.
2
1.2 Construction and function
In the original machines there was a keyed
connection (two flats) between the shaft/gearwheel
and chain sprocket.
New machines feature a friction-locked
connection. Power is transmitted via three cup
springs and two washers on either side of the chain
sprocket. The interference fit of the washers
provides the frictional torque to drive the chain
sprocket.
The cup springs are centered by a collar screw
which is screwed into the gearwheel shaft
(left-hand thread). Page 2 of 3
Technical Information 40.94 - Page 2
Service note
A friction clutch can be backfitted to any STIHL
E 20 electric saw. For this purpose it is necessary
to replace the gearwheel and chain sprocket cover
in addition to the parts shown in the illustration on
page 1.
If the chain sprocket has to be replaced on
machines with a friction clutch (from machine No.
X 31 010 462), note that a new collar screw must
be fitted as well. Cup springs must always be
replaced in sets of three.
The shape of the mounting hole is the only
difference between the new version of the chain
sprocket (round hole) and the original version
(two flats).
A modified chain sprocket cover is installed with
the friction clutch. The assembly sequence of the
friction clutch (see illustration on page 1) is shown
on the inside of the new chain sprocket cover.
The original sprocket covers must not be used
101TI002
with the new chain sprocket (friction clutch). The 1 2
new version of the sprocket cover may also be
used in older machines (without friction clutch).
1 = Original sprocket
2 = New sprocket
2. Nameplate
The original aluminium nameplates
1207 967 1500/05 will be replaced by the new
clip-in plastic versions 1207 967 1501/02.
The two round head rivets 0000 974 1000 have
been deleted.
The new nameplates are produced in a two-
component process in which the logo is imbedded
101TI001
in the carrier material. This means that the
appearance of the nameplate is not spoiled if its
surface is scratched. The nameplate remains
legible over a considerably longer period of time. Page 3 of 3
Technical Information 40.94 - Page 3
3. Summary
Part Name Original New Key Rem. MOQ
version version H
3.1
Chain sprocket cover 1207 648 0400 1207 648 0405 1 1) 1
Gearwheel (ring gear) 1207 640 7500 1207 640 7505 2 1) 1
Sprocket 3/8" 8T (complete); --- 1207 640 2050 3 1
including
items 4 und 5:
Sprocket 3/8" 8T 1207 642 1310 -*- 4 2), 3)
Collar screw --- 1207 162 4200 5 5
Sprocket 0.325" 8T (complete); --- 1207 640 2051 3 1
including
items 4 and 5:
Sprocket 0.325" 8T 1207 642 1311 -*- 4 2), 3)
Collar screw --- 1207 162 4200 5 5
Set of cup springs/washers; --- 1207 007 1002 6
including
items 7 and 8:
Washer (2) ---
1207 162 8900 7 1
Cup spring (3) --- 9485 648 2044 8 1
Washer 0000 958 1218 --- 9 3)
E-clip 9460 624 1001 --- 10 3)
3.2
Nameplate E 20 1207 967 1500 1207 967 1501 11 3) 1
Nameplate E 20 C 1207 967 1505 1207 967 1502 12 3) 1
Rivet (2x) 0000 974 1000 --- 13 3)
Modification to be introduced: 3.1: from machine number X 31 010 462
3.2: in progress
Remarks
1) Original version of part will be supplied from factory only as long as existing stocks last
2) New version of part is not available as separate item
3) Original version of part remains available for older machines
Last Technical Information on model E 20 electric saws: 35.92
Waiblingen, November 18, 1994 Andreas Stihl
D1/MTK-al Technical Documentation Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.