Rexnord AUTOGARD 400 Series User manual

D40014 Edition 17th September 2018 The English language version constitutes “Original Instructions”
in accordance with the EU Machinery Directive
AUTOGARD 400 SERIES TORQUE LIMITER
Installation and Maintenance
Instructions

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
Telephone: [phone] Fax: [phone] September 2018 (Supersedes December 2009)
http://www.rexnord.com 2
Contents
1. Technical Data.....................................................................................................................................................3
Standard parts (Figure 1)................................................................................................................................3
General Technical Data...................................................................................................................................4
1.2.1 Size 1-5 ...................................................................................................................................................4
1.2.2 Size 6-8 ...................................................................................................................................................6
Other Models...................................................................................................................................................8
1.3.1 Model 402 for sprockets, pulley and gears .............................................................................................8
1.3.2 Model 406N with N-Eupex elastomeric coupling.....................................................................................9
1.3.3 Model 409 with large bore hub..............................................................................................................10
2. General Notes....................................................................................................................................................11
General..........................................................................................................................................................11
3. Safety Notes ......................................................................................................................................................11
Safety Notes..................................................................................................................................................11
Safety Notes - Continued..............................................................................................................................12
Notes used in the Operating Instructions......................................................................................................12
4. Handling and Storage.......................................................................................................................................13
Scope of supply.............................................................................................................................................13
Handling ........................................................................................................................................................13
Storage..........................................................................................................................................................13
5. Technical description.......................................................................................................................................14
General description .......................................................................................................................................14
Torque transmission......................................................................................................................................14
Disengagement process................................................................................................................................15
Reengagement..............................................................................................................................................15
6. Installation .........................................................................................................................................................15
Finish boring..................................................................................................................................................15
Securing axially on the shaft .........................................................................................................................15
Balancing.......................................................................................................................................................15
General installation notes..............................................................................................................................16
Mounting a sprocket, gear or pulley (Models 402, 409)................................................................................16
Mounting Torque Limiter on the Shaft...........................................................................................................16
6.6.1 Models 402, 409....................................................................................................................................16
6.6.2 Model 406..............................................................................................................................................16
6.6.3 Model 403..............................................................................................................................................16
7. Startup................................................................................................................................................................17
Before startup................................................................................................................................................17
Torque adjustment ........................................................................................................................................17
7.2.1 Actuating torque adjustment with Sizes 1-5..........................................................................................17
7.2.2 Torque adjustment with Sizes 6-8.........................................................................................................18
8. Operation...........................................................................................................................................................21
General data..................................................................................................................................................21
9. Troubleshooting................................................................................................................................................22
General..........................................................................................................................................................22
Normal Operation..........................................................................................................................................22
Troubleshooting Guide..................................................................................................................................22
10. Maintenance and servicing..............................................................................................................................24
General......................................................................................................................................................24
Disassembly of sizes 1 - 5.........................................................................................................................24
Assembly of sizes 1 – 5.............................................................................................................................26
Disassembly of sizes 6 - 8.........................................................................................................................28
Assembly of sizes 6 - 8 .............................................................................................................................30
Lubricants..................................................................................................................................................32
11. Stocking spare parts, Customer facility addresses......................................................................................32

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
Telephone: [phone] Fax: [phone] September 2018 (Supersedes December 2009)
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1. Technical Data
Standard parts (Figure 1)
Part
Number
Description
Spares
Code
Part
Number
Description
Spares
code
21
Hub
B
42
Pawl
B
22
Slide plate
B
43
Tape journal bearing
A
23
Adjusting nut
C
44
Tape thrust bearing
A
24
Strut ring
C
45
Adapter ball bearing
B
25
Drive plate
B
46
Cage plate spring
C
26
Cage plate
B
52
Clamp collar
C
27
Calibration spacer
C
53
Adjustment spacer
C
28
Adapter
C
54
Adjuster screw
C
29
Pawl spring
A
55
Washer
C
30
Torque spring outer
(spring stack > size 5)
C
56
Spring pillar
C
31
Torque spring inner
C
57
Ball bearing (SR strut
ring only)
A
32
Drive balls
A
58
Switch plate / cover
B
33
Needle thrust bearing
A
59
Switch plate fixing
screw
B
34
-
60
Felt strip – switch
plate cover
A
35
Roll pin for SR pawl
B
61
Drive plate cover
B
36
Stop pin outer
B
62
Felt strip – drive
plate cover
A
37
Adapter bolt
A
63
-
38
-
64
Locking peg
C
39
Adapter dowel pin
A
65
Locking peg screw
C
40
Adjusting nut locking
screw
A
66
-
41
Stop pin inner
B
67
Bearing spacer
C
Spares Codes:
A = Standard service item – spares stock is recommended
B = Potential service item – spares stock is recommended in critical applications
C= Spares stock is not normally required
For details of specifications, part number and quantities required for specific sizes and models, please contact
Rexnord.

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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General Technical Data
1.2.1 Size 1-5
•Type RR (Rapid Reset) is supplied as standard.
•Type SR (Synchronous Reset) if supplied is specified with order.
•In the case of Type RR, Part 57 is omitted.
•In the case of type RR, parts 35 (anti-rotation pins from pawls) are omitted.
•Cage plate spring (46) is only used in Type SR Size 1
•Protective cover (61) and sealing strips (60,62) are special equipment
•Figure 1 refers to a model 403. Refer to section 1.3 for other models.
RR Top
SR Bottom Figure 1

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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Size
Max
Torque
Setting
Tmax
Nm
Speed
(3)
Nmax
1/min
D
max
mm
da
mm
d1
mm
d2
mm
x
mm
z
mm
k
mm
s
lB
mm
l1
mm
l3
mm
l4
(1)
mm
Wt.
(2)
kg
1
28
3000
16
62
30
110
1.5
1.5
41.3
5xM4
30
59
9.2
22.4
1
2
225
3000
28
112
75
140
2.8
4.8
92
6xM8
50
108
15.8
43.7
5.5
3
680
3000
40
146
95
184
3.5
4.8
114
7xM10
70
114
15.8
44.7
10.5
4
1130
2000
50
168
122
203
3.5
4.8
144
8xM12
75
121
15.8
45.9
15
5
2540
2000
75
222
155
280
4.4
6.4
184
8xM16
110
163
25.4
68.9
36
Table 1: Maximum actuating torque Tmax, speed nmax, weights and dimensions
1) Dimension without cover 61
2) Weights apply to maximum bore size
3) Higher speeds may be permitted – consult Rexnord.
The torque settings are applicable to:
•Daily operation up to 24 hours between operations.
•Operation in the temperature range from –15 C to +80 C (ambient temperature of shaft ends)
•Note that the set torque must be high enough to withstand start up torques.
•Rexnord Autogard Torque Limiters are supplied with a durable surface protection, so that no painting is
necessary. If however, paint is applied by the customer, the following points should be observed:
- Do not clean the coupling by pressure washing or solvent dip. It may be wiped clean only. Grease and
oil might be washed off which can only be replaced by disassembly of the torque limiter.
- The torque limiter may only be painted on its outer surfaces. When doing so, ensure that no paint is
allowed to penetrate into the unit or into gaps between components.
•To ensure sustained trouble-free operation, the torque limiter must be designed for the application
involved. In the event of any change in the operating conditions (Power, speed, modifications to prime
mover and driven machine), it is essential to check the design.
Caution

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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1.2.2 Size 6-8
* In the case of type RR, parts 35 (anti-rotation pins for pawls) are omitted
403-RR Top
403-SR Bottom

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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Size
Max
Torque
Setting
Tmax
Nm
Spee
d
Nmax
1/min
D
max
mm
da
mm
D1
J6
Mm
d2
mm
w
mm
x
mm
z
mm
k
mm
s
lB
mm
l1
mm
l3
mm
l4
mm
Wt.
(1)
kg
6
5650
1500
100
263
200
304.8
9.5
5.3
36.5
228
9x
M16
150
217
24
79
55
7
8600
11300
1500
1500
125
480
520
265
295
406.4
12.7
6.3
6
440
480
10x
M20
210
245
35
87.3
125
140
8
13800
17600
24850
1000
1000
1000
150
575
615
655
325
355
370
476.2
NA
8.1
8
528
568
608
10x
M24
240
300
38
120
225
235
250
9
31600
40800
56500
1000
1000
950
175
730
780
830
410
440
480
546.1
NA
10
8
670
720
770
10x
M30
270
410
40
158
530
550
570
Table 2: Maximum actuating torque Tmax, speeds nmax, weights and dimensions
1) Weights apply to maximum hole sizes
The torque settings are applicable to:
•Daily operation up to 24 hours between operations.
•Operating in the temperature range from –15 C to +80 C (ambient temp or temp of shaft ends.)
•Note that the set torque must be high enough to withstand start up torques.
•Rexnord Autogard Torque Limiters are supplied with a durable surface protection, so that no painting is
necessary. If however, paint is applied by the customer, the following points should be observed:
- Do not clean the coupling by pressure washing or solvent dip. It may be wiped clean only. Grease and
oil might be washed off which can only be replaced by disassembly of the torque limiter.
- The torque limiter may only be painted on its outer surfaces. When doing so, ensure that no paint is
allowed to penetrate into the unit or into gaps between components.
•To ensure sustained trouble-free operation, the torque limiter must be designed for the application
involved. In the event of any change in the operating conditions (Power, speed, modifications to prime
mover and driven machine), it is essential to check the design.
Caution

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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Other Models
1.3.1 Model 402 for sprockets, pulley and gears
Size
Lmax
Kmax
Omax
H
X2
X3
Z2
G
P
Q
R
1
83
33.5
25
0
3xM3
3x φ4
6
25
30
35
38
2
148
57
44.5
0
3xM4
3x φ4
9
40
46
52
61
3
160
55
43
4.76
3xM6
3x φ8
11
55
63
75
80
4
212
100
84
4.76
3xM8
3x φ10
11
65
72
85
90
5
284
134
116
6.35
4xM8
4x φ10
11
100
107.95
120
125
6
373
181
-
-
-
-
-
-
-
-
-
Table: 3
dimensions in mm
For customer fitted drive media, a suitable oil filled bronze bearing is supplied with the unit. Bore the
drive medium to φP (H7) to provide a housing for the bearing. The bearing may be shortened to suit the actual
length of the drive medium.
Before fitting make sure that all sharp edges are removed. The bearing must be free from grit and dust. Wash in oil
to clean and re-oil if the bearing has dried out. To re-oil, immerse in mineral oil ISO VG68
or VG150 (SAE 30 or 40) at 60-70°C for 10-15 minutes, then cool in cold oil.
To fit the bearing, apply steady pressure using a flanged fitting pin. Never use hammer blows. The fitting pin shaft
should be machined to φG m5. The bearing is made to ISO 2795 tolerances. When fitted
in a rigid H7 housing using an m5 fitting pin, the resulting bore will be H7 which will provide a running
fit on the torque limiter hub.
If a different bearing is used or for sizes 6 and over, refer to drawings or consult Rexnord.

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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1.3.2 Model 406N with N-Eupex elastomeric coupling.
Size
L
T1
T2
K
S2
max
R
P
min
P
max
∆P
b
1
88.4
59
20
0
24
68
2
4
0.2
0.2
2
179
108
50
19
55
125
2
4
0.25
0.25
3
203
114
60
21
65
160
2
6
0.3
0.3
4
232
121
80
33
85
200
2
6
0.3
0.3
5
305
164
100
40
100
250
3
8
0.35
0.35
6
357
217
125
55
120
315
3
8
0.4
0.4
7
463
245
180
94
160
440
5
10
0.6
0.6
Table: 6
dimensions in mm
Misalignment data is valid for 1500rpm. For other speeds please use this formula:
n
R
bP 40
1000
1.0 ×





+==∆
Where n is speed in rpm and R is taken from Table 6.

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1.3.3 Model 409 with large bore hub
Size
L
N
K
S1
max
G
P
X1
UNC
X2
Z1
Z2
1
94
51
43.9
28.6
38.1
53.98
8-32
3x4.75
7.9
7.1
2
148
65
57.2
41.3
57.2
76.2
10-24
6x4.75
9.5
9.5
3
181
90
84.1
54.0
76.2
98.43
½ -20
6x6.35
11
9.5
4
232
127
125.5
19.4
104.8
127
5/16 -18
6x7.94
12.7
12.7
5
303
165
164.3
102
139.7
165.1
3/8 -16
6x9.52
14.3
12.7
Table: 7
dimensions in mm
UNC threaded holes are 3 off equispaced.
For size 1, the pin and screw holes are equispaced in a pattern of 6.
For sizes 2-5, the 3 x screw holes are positioned at 30° to the 6 x pin holes.

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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2. General Notes
General
These Operating Instructions constitute part of the torque limiter supply. They should be kept in the vicinity of the
torque limiter at all times.
Only precise knowledge of the Operating Instructions will ensure trouble-free operation of the coupling. It is
therefore in the interest of the customer for the Operating Instructions to be read, understood and observed in all
respects by the persons responsible for handling, assembly and operation.
Note: We assume no liability for damage resulting from non-observance of the Operating Instructions.
The torque limiter dealt with in these Operating Instructions has been designed for use in general engineering. It
is intended for use in protecting industrial machinery and is not to be regarded as a safety device.
The torque limiter described here is in accordance with the state of the art at the time of printing these Operating
Instructions.
In the interest of further development, we reserve the right to introduce modifications which we consider
appropriate, while retaining the essential features, to increase efficiency and reliability.
All technical questions should be referred to Rexnord at,
British Autogard Ltd Telephone: [phone]
Cirencester Fax: [phone]
E-mail: [e-mail]
3. Safety Notes
Safety Notes
•The torque limiter is constructed in accordance with the state of the art and is reliable in the state as shipped.
Unauthorized modifications which impair reliability are not permissible. This also applies to safety devices
which are fitted as protection against accidental contact.
•The torque limiter may only be used and operated under the conditions specified in the performance and
supply contract.
•The customer has to ensure that the persons entrusted with installation, operation care and maintenance, as
well as repair, have read and understood these Operating Instructions and observe them in all respects in
order:
- To prevent hazard to life and limb on the part of the user and third parties.
- To ensure the reliability of the torque limiter.
- To prevent failure and environmental contamination resulting from improper handling.
- To comply with essential health and safety requirements.

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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Safety Notes - Continued
•During the course of handling, assembly and disassembly, operation, as well as care and maintenance, the
relevant regulations regarding industrial safety and pollution control are to be observed.
•The coupling may only be operated, maintained and repaired by authorised, trained and suitably supervised
personnel.
•All work should be carried out with due care and with the safety aspect in mind.
•Work on the coupling may only be carried when it is stationary. The drive unit must be isolated to prevent
accidental start-up (for example by locking the key switch or removing the fuses from the power supply). A
notice should be affixed to the start-up point stating that work on the torque limiter is in progress.
•During operation, the drive unit should be shut off immediately if changes in the torque limiter are detected,
such as for example changes in operating noises.
•The torque limiter must be protected to prevent accidental contact by means of a suitable guard.
•When the torque limiter is installed in equipment or systems, the manufacturer of the equipment or systems
is obliged to include the instructions, notes and description contained in these Operating Instructions in his
own Operating Instructions.
•It is the responsibility of the manufacturer of the equipment or system to ensure that local codes of safety are
complied with. (e.g. EC Safety of Machinery Regulations in Europe).
Notes used in the Operating Instructions
Important instructions contained in these Operating Instructions which concern operating safety are emphasised
as follows:
This symbol draws attention to measures which MUST be observed to prevent personal injury.
This symbol draws attention to measures which MUST be observed to prevent malfunction or
damage to the torque limiter.
Note: This note draws attention to general operating notes which special attention should be given.
Caution

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4. Handling and Storage
Scope of supply
The scope of supply of the shipment is listed in the despatch documents. It should be checked for completeness
on receipt. Any shipping damage and/or missing parts should be reported immediately in writing.
Handling
Packing of the torque limiter will differ, dependent on methods of shipment and size. The packing will, unless
agreed to the contrary, comply with Rexnord standards.
The symbols applied to the packing should be noted. Their significance is as follows:
Ensure that a suitable hoist is used
Storage
Rexnord Autogard Torque Limiters are supplied manganese-phosphated and oiled and can be stored in a dry
place for long periods of time. In the case of prolonged storage, the torque limiter should be covered to prevent
excessive contamination. Long-term preservation is only necessary for the finish bore.
If dirty, the torque limiter MUST be cleaned. However, avoid complete wash down as this can
wash oil and grease out of the interior of the torque limiter, necessitating complete
disassembly and re-lubrication.
Caution
Caution

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5. Technical description
General description
The Rexnord Autogard Torque Limiter is an overload protection coupling which protects motors, gear units and
machines from overload and destruction due to excessive torque and automatically interrupts the power train when
the torque setting is exceeded.
The actuating torque is directly dependent on the spring force which can be continuously adjusted by means of
adjuster nut (23). Dependent on the size of the torque limiter, either helical springs or disc springs are used.
Type RR and SR are the basic types giving rapid reset and synchronous reset respectively.
With both types, reengagement is effected automatically by reversing the direction of rotation, manually or by motor.
They differ in their different angles of reengagement.
In the case of Type RR, the reengagement angle is a maximum of 67 degrees, according to size.
The reengagement angle of Type SR is a maximum of 360 degrees. Torque limiters of this type will reengage in
every case in the same angular shaft position, hence the term synchronous reset.
When disengagement has occurred, investigate the cause and rectify before re-engagement.
In the case of motor-operated reengagement, it is essential to ensure a low reengagement
speed (<100 rpm ). This applies particularly to Type SR.
Torque transmission
The torque is transmitted by means of balls (32) which are located in conical recesses between two plates pressed
together by spring pressure (drive plate –25- and slide plate –22).
A second set of balls (32) on a smaller pitch circle lies in recesses in the slide plate (22) and is unloaded when the
coupling is engaged. The cage plate (26) retains the balls in position in relation to one another after disengagement
of the coupling. Thus, it assumes a function similar to that of the cage of a ball bearing.
Caution

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Disengagement process
When the running torque reaches a value which exceeds the set torque, the balls (32) of the outer pitch circle roll
under load out of their recesses. The disengagement process is now commenced and the drive path between
input and output sides of the drive is completely interrupted.
At the same time, the balls of the inner pitch circle are also rolled out of their recesses by the cage plate (26).
Then, the slide plate (22) and the drive plate (25) rotate in relation to one another until the outer balls (32) engage
in recesses (or escape seats) which are only present in the slide plate. Apart from any minimal residual torque,
caused by the friction in the journal bearings (43 and 44), no further torque is transmitted.
The balls (32) of the inner pitch circle are now positioned between ball seats and support the full load generated
by the springs (30 & 31). They maintain the slide plate (22) and the drive plate (25) at a distance by resting
against the strut ring (24). The balls on the outer pitch circle, previously responsible for torque transmission, are
at this moment unloaded. A pin (36) in the slide plate (22) prevents any further rotation of the slide plate in
relation to the cage plate (26). Reengagement of the outer balls in their recesses is prevented and as a result the
drive plate (25) can rotate freely on the hub. As a result of the disengagement of the torque limiter, the slide plate
(22) moves axially and with it, the limit switch plate (58). This axial movement (x) should be monitored with a limit
switch or a proximity switch.
Rexnord Autogard 400 Series Torque Limiters should be monitored with a limit switch or a
proximity switch in order to prevent unnecessary wear. Although these couplings can run for
some time in the disengaged state, periods exceeding several minutes should be avoided
(particularly with high-speed drive units).
Reengagement
Re-engagement takes place automatically as a result of reversing the direction of rotation of the drive unit or of
the output drive continuing to rotate with the drive motor stationary. When this happens, one of the spring-loaded
pawls (29) extends by following a ramp on the slide plate (22) into a cut out in the cage plate (46) and turns the
latter back until the balls (32) align with their original recesses in the drive plate. At this point, the pawl is forced
back into its hole in the drive plate (25) by a second ramp on the slide plate (22). The slide plate then continues
to rotate relative to the cage and drive plates until the slide plate seats are aligned with the balls. The mechanism
then snaps back into re-engagement.
Resetting must be done at low speed (<100rpm) to permit the engaging mechanism to
function properly in either direction and to prevent potential damage. It should be done
manually or by slowly inching the motor in reverse. Other methods are possible, but it is
essential to ensure slow differential speed between input and output during re-setting.
6. Installation
Finish boring
Rexnord Autogard Torque Limiters are normally supplied bored and keywayed. Couplings without bore and
keyway cannot be set to an exact actuating torque. Please contact Rexnord for advise.
Securing axially on the shaft
The coupling halves are secured by means of setscrews (cup point) or with and end plate and central locking
screw. The length of the setscrews should be such that it fills the tapped hole, but does not project
past the outside diameter (Lmin=setscrew diam x 1.2).
Balancing
Rexnord Autogard Torque Limiters are generally supplied without special balancing. If a special application (for
example high rpm and large coupling size) necessitates balancing or it is required by the customer, this
balancing can be carried out at our works and must be specified at the time of order. Type SR must be specified
if the unit is to be balanced.
Caution
Caution

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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General installation notes
During installation, the Safety Notes in Section 3 should be observed. Installation should be carried out with
extreme care by specialist personnel. Ensure right at the planning stage that there is adequate space available
for installation and subsequent care and maintenance. Adequate hoists must be available when installation is
commenced.
Mounting a sprocket, gear or pulley (Models 402, 409)
If not supplied with the unit, a sprocket, gear or pulley may be mounted by bolting to the adaptor. Fixing
dimensions are given in tables 3 and 7.
In the case of Model 402, a bearing is supplied, which the customer may fit in the sprocket, gears or pulley. The
required boring dimensions are given in the table. The bearing may be shortened to suit.
For 402 size 6 and above a suitable bearing must be supplied by the customer.
For 409, the customer should supply and fit their own bearing to suit the dimensions shown in Table 7.
It is essential that fixing bolts or pins do not protrude through the adapter and interfere with
the internal mechanism of the torque limiter.
Please select all bolts and pin lengths carefully.
Mounting Torque Limiter on the Shaft
Before commencing installation, the shaft ends and the torque limiter bores should be carefully cleaned. Avoid oil
and grease being washed out of the interior of the torque limiter; this will necessitate complete disassembly and
re-lubrication.
6.6.1 Models 402, 409
With the torque limiter completely assembled, carefully engage the hub bore on the shaft. The standard
clearance fit bore should permit the hub to be pushed or lightly tapped in place on the shaft.
Do not strike with heavy hammer blows on the hub. On no account must direct heat be
applied to the torque limiter.
Once on the shaft, the torque limiter should be moved axially to obtain proper alignment of the sprocket, gear
or pulley. Once in position, tighten the set screws.
6.6.2 Model 406
Mount the torque limiter on one shaft as described in 6.6.1. Mount the in-line coupling hub to the other shaft in
a similar manner. Bring the shafts together and assemble the coupling, observing the shaft alignment
requirements shown in tables 4, 5 and 6.
6.6.3 Model 403
For Model 403, the driven member is supplied by the customer. If used for an offset drive, the sprocket, pulley
or gear must be mounted on its own bearing. If a coupling hub is fitted, follow the manufacturer’s
recommendations for alignment.
Nonobservance of these notes can lead to torque limiter damage and in extreme cases break
up of parts. Flying fragments are a serious hazard and must be prevented.
Caution
Caution

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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7. Startup
Before startup
The tightness of the setscrews should be checked and the coupling guard fitted.
Torque adjustment
Rexnord Autogard Torque Limiters are supplied set to a fixed torque value in accordance with the customer’s
requirements if specified at time of order, otherwise it will be set near minimum trip torque. If the exact actuating
torque cannot be determined beforehand, an actuating torque range can also be stated.
In the case of Sizes 1-5, the torque limiter can then be set experimentally, but a calibration spacer (27) designed
for the max torque will be fitted. This will make it possible to adjust the actuating torque without the necessity for
removing the coupling from the shaft.
To set experimentally, start up the drive at a low torque setting. If the torque limiter disengages before normal
operating load is reached, progressively increase the torque setting until the drive will start and run without
tripping, under normal conditions. An approximate torque setting may also be determined from standard
calibration curves which are available from Rexnord Autogard.
For couplings of Sizes 6-8, an individual calibration curve is normally provided. Generally, a Rexnord Autogard
Torque Limiter can only be adjusted within the range stated on the calibration curve.
Response of the Rexnord Autogard Torque Limiter should never be interpreted as a
malfunction, but as an indication of the fact that higher torque values are occurring in
practical operation than were previously determined theoretically. In this case the cause
should be determined and the torque setting increased only if the reason for disengagement
is fully understood.
7.2.1 Actuating torque adjustment with Sizes 1-5
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British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
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ON NO ACCOUNT should calibration spacers (27) be removed, as otherwise no guarantee can be
given of disengagement of the coupling. Replacement of springs with a stronger or weaker set,
and shortening the calibration sleeve are ONLY permissible with the EXPRESS approval of
Rexnord Autogard.
•First of all, the locking screws (40) of the adjusting nut (23) should be slackened. These locking screws
prevent accidental rotation of the adjusting nut during operation.
•Increasing the set torque;
- The torque is increased by turning the adjustment nut (23) clockwise. The calibration spacer (27)
underneath the adjusting nut restricts the maximum set torque.
When increasing the set torque, it is ESSENTIAL to note that the torque may only be increased
to the extent that even the weakest component in the drive train is still adequately protected.
•Reducing the set torque
- The set torque is reduced by turning the adjustment nut (23) anticlockwise. When reducing the torque, a
minimum actuating torque should be observed which must be maintained, as otherwise proper actuation
of the torque limiter cannot be ensured.
•After carrying out the torque adjustment, the locking screws (40) should be cleaned and smeared with Loctite
243 and then retightened.
7.2.2 Torque adjustment with Sizes 6-8
403-6RR
403-6SR
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British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
Telephone: [phone] Fax: [phone] September 2018 (Supersedes December 2009)
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The maximum and minimum torque of the torque limiter and the spring set installed (30) is
specified by the setting curve. Further increase or reduction is not possible, as otherwise the
proper function of the Rexnord Autogard Torque Limiter cannot be guaranteed. It may still be
possible to fit a different spring set. In such cases, Rexnord should be consulted.
•Take into account the minimum space required P. Torque adjustment can be carried out without removing the
coupling from the shaft.
•For the purpose of torque adjustment, slacken the two screws (65) holding the locking peg (64) against the
adjustment nut (23). This locking peg locks the position and setting of the adjustment nut during operation.
•After removing the screws (54) and the adjustment spacers (53), the screws (54) should be screwed into the
spring pillars (56) again, with washer (55) fitted. Omit the switch plate (58) if fitted. Tighten the screws (54), so
that each spring stack is compressed in sequence. According to the size and torque range, between 4 and 12
spring stacks are fitted.
•Increasing the set torque
- When the spring stacks (30) have been compressed, ensure that the hexagonal flange of the spring pillar
(56) is not pulled out of the annular groove in the slide plate (22), that is to say that each screw (54),
should after contact with the washer (55) on the adjustment nut (23), only be tightened 1.5 turns in the
case of coupling sizes 6 and 7 and 1 turn in the case of size 8.
- The adjustment nut (23) can now be turned freely clockwise in order to increase the actuating torque, until
turning resistance is encountered (after approximately 1.25 – 1.4 turns). The maximum actuating torque
is reached when the end of the spring pillar (56) is flush with the end of the adjusting nut (23). If the end
of the spring pillar is projecting, proper function of the Rexnord Autogard Torque Limiter can no longer be
ensured.
When increasing the actuating torque, it is ESSENTIAL to note that the actuating torque may only
be increased to the extent that even the weakest component in the power train is still adequately
protected.
•Reducing the set torque
- When pretensioning the spring stacks (30), ensure that the hexagonal flange of the spring pillar (56) is not
pulled out of the annular groove of the slide plate. Each screw (54) , should only be tightened 1.0 turns in
the case of coupling size 6 and 7, and 0.5 turns in the case of size 8 after contact with washer (55).
- When all the spring stacks (30), have been pretensioned, the adjusting nut (23) can be turned freely anti-
clockwise in order to reduce the torque, but only by a maximum of 0.5 turns, so that the hexagonal
flanges of the spring pillar (56) are not pulled out of the groove in the slide plate.
•The adjusting nut must be positioned after adjustment so that it can be locked by means of the locking peg
(64). To do this, align the tapped holes in the adjusting nut (23) either side of the groove in the hub.
•Next slacken the screws (54) to release the tension in springs (30). The spring pressure now acts directly on
the slide plate (22) and the torque is now re-set.
•Install the adjustment spacers (53), screw the screws into the spring locating pin (56) again and tighten fully.
The torque can not be adjusted with adjustment spacers fitted.
Caution

British Autogard Ltd. 2 Wilkinson Road, Cirencester, Gloucestershire, GL7 1YT, UK D40014
Telephone: [phone] Fax: [phone] September 2018 (Supersedes December 2009)
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When the adjustment spacer (53) is fitted, a small gap must always be present between the
washer (53) and the adjusting nut (23).
•By means of a test run check whether the system can be operated as required. If further torque adjustment is
necessary, the adjustment procedure should be repeated.
•When adjustment is complete, the adjustment nut (23) should be locked in the required position again by means
of the locking peg (64). The screws (65) should be cleaned, smeared with Loctite 243 and fully re-tightened.
Table 7.1 – Torque ranges and spring sets
Size
Torque range
Designation of
helical spring set
Gap ‘Y’ mm
Clearance
movement
For X
(mm)
Adjustment to
A
Disengage
From
Nm
To
Nm
Qty Pos.
Torque
Max Min
1
15
11
6
3
28
21
14
7
8 outer
6 outer
4 outer
2 outer
1.9 2.8
N/A 1.5
2
80
60
40
20
220
170
115
60
8 outer
6 outer
4 outer
2 outer
5.1 10.2
N/A 2.9
3
250
160
110
60
678
450
300
150
6 inner +outer
6 outer
4 outer
2 outer
5.1 10.2
N/A 3.5
4
500
350
260
160
75
1130
750
560
375
190
8 inner +outer
8 outer
6 outer
3 outer
2 outer
5.1 10.2
N/A 3.5
5
1200
900
680
450
225
2540
2000
1500
1000
500
8 inner +outer
8 outer
6 outer
4 outer
2 outer
5.1 15.2
N/A 4.4
6
2250
1700
1100
5650
4250
2800
8 Spring Stacks
6 “ “
4 “ “
26.7 38.1
9.5 5.3
7
4500
3000
2250
1500
11300
7500
5650
3800
12 Spring Stacks
8 “ “
6 “ “
4 “ “
29.2 ---
12.7 6.3
8
24860 max
18645 max
12430 max
12 Spring Stacks
8 “ “
6 “ “
52.1 ---
25.4 8.0
Refer to figures on the following page for Gap Y, Clearance A and movement X.
Caution