GB

03

RINGFEDER

Locking Assemblies

RfN 7014

For high torques &

axial loads

04
Catalogue

RINGFEDER Locking Assemblies RfN 7014

Please note that our guarantee refers to our products only. Because of the unlimited number of applications and all different types of machines, it is
not possible for our engineers to know all factors
that may affect or change the technical data or our
products.

This publication may not be reproduced, either partly or wholly, without the source being quoted.
We reserve the right to modify design by way of
technical improvement.

Certified by DIN EN ISO 9001 and DIN EN ISO 140001 and ISO/TS 16949

RINGFEDER Locking Assemblies RfN 7014

For highly stressed shaft-hub connections
the shrink fit is unsurpassable. No other shaft-hub connection
can offer anywhere near the same performance regarding fatigue
stress under alternating torsional loads. However, the traditional
shrink fit has drawbacks, as they call for involved calculations
and extremely close machining tolerances. The fitting and removal of these connections is difficult, subsequent adjustment
can be impossible.
The connection using a RINGFEDER RfN 7014 Locking Assembly is a shrink fit
but a shrink fit of a special kind. With all the advantages and
none of the disadvantages.
Fig. 1 Locking Assembly RINGFEDER RfN 7014

CHARACTERISTICS

HIGH TRANSMISSION FORCES

Due to the narrow cone angles high torques & axial forces can
be transmitted.

UNLIMITED RANGE OF APPLICATIONS

RfN 7014 Locking Assemblies are suitable for securing all types
of bosses and hubs onto shafts and axles. Replacing traditional shrink fits, key and polygon connections, splined shafts etc.

OPTIMUM DEPENDABILITY

We guarantee the torque/axial load transmission values as given in this publication, regardless of whether the connection is
subjected to static, dynamic or impact loads. However, the values given in this catalogue must not be exceeded.

SIMPLIFIED MANUFACTURING

Locking Assembly connections only require plain shaft and

bore diameters, no additional components or machining of
steps, slots, threaded holes, etc. is necessary. Also due to the
RfN 7014 Locking Assembly design, hubs can be manufactured
with through bores, depending on the centering accuracy required.

GOOD CENTERING ABILITY

Due to the relatively wide design (giving increased guiding

lengths) RfN 7014 Locking Assemblies centre better than the
standard series RfN 7012.

EASY MOUNTING

Hubs can be located at any point on the shaft and adjusted to

precise angles. The RfN 7014 Locking Assembly uses a few
standard cap headed screws tightened to a specific torque value.

EASY REMOVAL

The RfN 7014 Locking Assembly is released using the locking

screws in the threaded jacking hole positions. No additional
measures or auxiliary devices are required. A small shoulder on
the shaft or in the hub bore is required for releasing (please refer to page 7).

HIGH FATIGUE STRENGTH UNDER

ALTERNATING TORSIONAL STRESSES

As neither the shaft or hub feature grooves the notch effect is

minimised giving a higher polar section modulus.

OVERLOAD PROTECTION

When the admissible load is exceeded the Locking Assembly

will slip. In this way they protect valuable machine components
against damage. However, Locking Assemblies are subject to
the same laws as all other friction connections and are not suitable for use as slipping clutches.

EASY ADJUSTABILITY

The Locking Assembly connection can be adjusted at any time

by following removal and fitting instructions.

PERFECT TRUE RUNNING

There is no play or fretting wear with a RfN 7014 Locking Assembly friction connection.

EASY CALCULATION

This catalogue lists all relevant data in the form of quick-reference tables.
3

Locking Assemblies RINGFEDER RfN 7014

Locking Assembly designation for shaft diameter d = 70 mm: Locking Assembly RINGFEDER 70 x 120 RfN 7014

Surface Pressure
Locking Assembly dimensions

dxD
mm
70
80
90
100
110
120
130
140
150
160
170
180
190
200
220
240
260
280
300

x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x

L
120
130
140
160
170
180
190
200
210
230
240
250
260
270
300
320
340
370
390

62
62
62
80
80
80
80
80
80
94
94
94
94
94
116
116
116
136
136

l
mm
56
56
56
74
74
74
74
74
74
88
88
88
88
88
110
110
110
130
130

L1
74
74
74
94
94
94
94
94
94
110
110
110
110
110
134
134
134
156
156

Transmissible
torques
axial
forces
T or
Nm
6850
11650
13000
19700
26600
28900
31200
40200
42900
64000
67800
83000
88000
105000
123000
153000
186000
230000
245000

shaft

hub

Fax
kN

Qty.

197
291
290
389
483
482
480
574
572
800
795
923
921
1050
1120
1280
1430
1650
1650

201
263
234
213
242
222
205
227
212
227
214
235
223
242
189
198
205
192
179

117
162
150
133
157
148
140
159
152
158
152
170
163
179
138
148
157
145
138

8
12
12
12
14
15
15
17
18
17
18
20
21
23
21
24
26
24
24

Releasing
threads

dG

Qty.

TA
Nm

kg

M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M

4
4
4
4
4
5
5
5
6
5
6
5
6
5
6
6
6
6
8

145
145
145
230
230
230
230
230
230
355
355
355
355
355
485
485
485
690
690

3,3
3,7
4
7,2
7,7
8,3
8,8
9,3
10
14,9
15,7
16,4
17,2
18,8
27,7
29,8
32
46
49

12
12
12
14
14
14
14
14
14
16
16
16
16
16
18
18
18
20
20

x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x

55
55
55
70
70
70
70
70
70
80
80
80
80
80
100
100
100
120
120

Weight

Mounting of Locking Asembly

The values for T, Fax, p and p apply to Locking Assemblies installed in an oiled condition.

d x D, L, l, L1 = Basic dimensions, Locking Assemblies not

tightend

for further details see page 6.

Surface finishes

dG = Clamping/releasing thread

For shaft and hub bores:

Ra
3,2 m.
Corresponds to RMS 125 micro-inches.

= Transmissible torque

Fax = Transmissible axial force

p

Thread

N/mm2

Explanations

Locking screws DIN 91212.9

between Locking
Assembly and

Tolerances

= Maximum surface pressure between Locking

Assembly and shaft

We do not stipulate any particular tolerances. The following may

be taken as guide values:

p = Maximum surface pressure between Locking

Assembly and hub

Shaft: All clearances between h9 and k9.

Hub: All clearances between N9 and H9.

TA = Maximum tightening torque for the screw considered

in order to determine the values T, Fax, p and p

In order to avoid impairments of functioning, the clearances

chosen for shaft and hub must permit a correct and symmetric
clamping, i.e. if the shaft is smaller than nominal d, the bore
should be accordingly greater than nominal D and vice versa.
Location of several Locking Assemblies RfN 7014
Two Locking Assemblies at most can be installed in series. In
this case the transmission values of the above table will double.
Change of screw tightening torques
A reduction of the contact pressures and the transmission values by reducing the tightening torque of the screws is possible. The admissible lower limit results from the multiplication
of the TA values of the above table by 0,8.
There is an approximate linear relationship between TA, T,
Fax, p and p (hub and hollow shaft calculation according to
the equations on page 5)!

Fig. 2

Locking Assemblies RINGFEDER RfN 7014

Hub outside diameter DN as a factor of the yield point (minimum theoretical values)

chosen Rp0,2N (N/mm2)

200

70
80
90
100
110
120
130
140
150
160
170
180
190
200
220
240
260
280
300

dxD
mm

p
N/mm2

x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x

117
162
150
133
157
148
140
159
152
158
152
170
163
179
138
148
157
145
138

120
130
140
160
170
180
190
200
210
230
240
250
260
270
300
320
340
370
390

220

250

270

300

350

400

450

500

158
199
205
225
261
267
273
309
316
359
365
410
415
462
438
483
537
559
574

154
189
196
216
248
255
262
293
301
339
347
384
390
429
417
461
507
533
546

150
182
190
210
238
246
254
281
290
326
334
367
374
407
405
445
486
515
531

148
177
185
206
232
240
249
273
283
316
325
354
362
392
396
432
470
500
515

DN
mm
197

309
311
457
419
395
552
517

617

654
803

930
878

187
287
274
285
381
366
356
455
444
541
522

658

648
685
830
792
772

176
247
245
261
326
323
322
388
388
455
451
552
539
662
519
595
687
688
687

171
231
232
250
305
305
307
362
365
423
423
501
496
586
495
560
636
648
652

165
215
219
238
283
287
291
336
341
391
395
455
455
521
468
522
588
603
612

For hubs with B  b + k, but a minimum width B = L, you must

choose p for the preceding formulas instead of pred .

Explanations
The values apply to:
One Locking Assembly RfN 7014, fitted using oil
B  b + k; b  L1; k  L1 - L

If two Locking Assemblies are used in series, the values of the

above table also apply if the dimensions b and B are increased
by L1.

Calculation according to the following equations:

Shaft calculation (minimum requirements)

a) Applicable to solid shafts is: Rp0,2W  p
b) The admissible maximum bore diameter of a hollow shaft results from the following formula:

where Rp0,2N is the yield point of the hub material and pred the
surface pressure reduced to the zone of stress L1, i. e.:

where Rp0,2w is the yield point of the shaft material and pred the
surface pressure reduced to the zone of stress L1.

The following empirically determined relationship applies to the

form factor c:

The required yield point of the hub material or the admissible

surface pressure are to be determined according to the following formulas (units of meassure see table on pages 4 and 5):

Fig. 3

Locking Assemblies RINGFEDER RfN 7014

Installation and removal instructions
Removal

Installation
Since the force is transmitted by contact pressure and friction
between the functional surfaces, the condition of the contact
surfaces and correct tightening of the locking screws are of
great importance (see point 2).

The Locking Assemblies RfN 7014 are to be removed as

follows:

1. When originally packed, Locking Assemblies are fitted with

small metal packing pieces located in the slits of the inner
and outer rings. These are for shipping purposes only and
MUST be removed prior to installation.

2. Remove the screws adjacent to each threaded release hole

and screw them into these holes. Since the rear thrust ring
rests against either shaft or hub shoulder, the jack screws
will automatically push apart both tapers, thus releasing the
connection.

1. Loosen all screws by a few threads.

2. All contact surfaces, including screw threads and screw

head bearing surface, must be clean and slightly oiled (do
not use molybdenum disulphide). In this condition, the
shaft, hub, and Locking Assemblies are to be assembled.

3. The connection can be either re-adjusted or dis-assembled.

Remove the jack screws only after the Locking Assembly
has been taken out of the hub.

3. Tighten locking screws lightly and align hub.

Used Locking Assemblies have to be replaced and slightly oiled prior to reinstallation. Note that the release threads of the
of the front thrust ring have to be positioned opposite to undrilled spaces of the rear thrust ring. These threads are used
for removal.

4. Tighten screws evenly in diametrically opposite sequence

and do this in two or three stages up to the indicated final
tightening torque (TA).
5. Re-check tightening torque by applying it to all the screws.
When no screw turns any more, the assembly is completed.

Fig. 5 Locking Assembly with a screw in one of the realease threads

Fig. 4 Locking Assembly not tightened

Locking Assemblies RINGFEDER RfN 7014

Construction hints / Construction examples

Fig. 6 Arrangement of a Locking Assembly RfN 7014 supported by the hub.

Fig. 7 For hubs with comparatively small outside diameters it is recommended

to step the shaft in order to obtain a sufficient hub section above the Locking
Assembly (support by he hub).

Fig. 8 Arrangement of a Locking Assembly RfN 7014 supported by the shaft.

Fig. 9 In the case of straight through hub bores and shafts without steps or
shoulders, it must be possible to push the rear thrust ring of the Locking Assembly against another construction part in order to release the assembly.

Fig. 10 Venturi nozzle for the gaspurifying, converter.

Flap fastening Locking Asemblies 90 x 140 RfN 7014
Messrs. BAUMCO, Essen

Fig. 11 Rolling crusher

Fastening of a gearwheel with a Locking Assembly 160 x 230 RfN 7014
Messrs . Hazemag, Mnster

Material standards selection

Hints for material specifications and according values of yield strength

replaced by

DIN

DIN EN

designation

aproximate range
of yield point*
N/mm2

1629

seamless tubes
for
special requirements

215

up to

355

1681

cast steel
for
common use

200

up to

300

Beibl. 1
1691

cast iron

1692

malleable cast iron

200

up to

530

1693

spheroidal graphite cast iron

250

up to

500

1705

copper - tin
and
copper - tin - zinc - alloys

90

up to

180

98 up to 228
(0,1 limit of elongation)

1725

575

aluminium alloys

70

up to

380

17100

10025

structural and constructural steels

175

up to

365

17200

10083

heat-treatable steel

300

up to

560

17245

ferritic creep resistant cast steel

125

up to

540

17440

stainless steels

185

up to

600

* dependent on quality, kind of product and intended use

ISO-tolerances for shafts and bores

Allowances in m (1 m = 39.37 in)

Technical service
Based on your technical drawings and data we are ready
to execute installation proposals to solve your specific
problems.
Many years of experience and modern calculation methods open extraordinary possibilities of assistance.

Certified

Fax enquiry

+49 (0) 2151 835 200 or 207

For technical assistance

To: RINGFEDER VBG GMBH, department MV

From:
Messrs.: ..................................................................
..................................................................................
..................................................................................

address: ................................................................
..................................................................................
..................................................................................

contact: ...................................................................

phone: ..................................................................

department: ............................................................

fax: .........................................................................

To make it easier for our technical staff and to avoid errors or mistakes your enquiry should include the following information:

Information for technical service

Expected maximum loads:
Max. torque
Max. bending moment
Max. axiall load
Max. radial load

Tg
Mg
Fg
Fr

max.
max.
max.
max.

=
=
=
=

Nm
Nm
kN
kN

=
=
=
=
=
=
=
=

mm
mm
1/min
mm
mm
N/mm2
N/mm2
C

Dimensionens, materials:
shaft diameter
In case of hollow shaft, internal diameter
Speed/revolutions
Hub outside diameter
Hub width
Hub material/yield strength
Shaft material/yield strength
Temperature at the connection

dW
dB
n
DN
B
Rp0,2N
Rp0,2W
Temp.

Additional information:

.................................................................................
.................................................................................
.................................................................................
.................................................................................

Please send a drawing or sketch together with your enquiry!

RINGFEDER VBG GMBH Oberschlesienstr. 15 D-47807 Krefeld
P.O.Box 130619 D-47758 Krefeld
Phone +49 (0) 2151- 835-0 Fax +49 (0) 2151- 835-200/207
http://www.ringfeder.de e-mail: info@ringfeder.de

RINGFLEX Drive Systems Limited

Unit 34, Vauxhall Industrial Estate
Greg Street, Reddish GB Stockport SK5 7BR
Phone (0161) 4740464 Fax (0161) 4290272

RINGFEDER Locking Assemblies RfN 7012 . . . . . . . . . . . for highly stressed shaft-hub connections
and big machining tolerances
RINGFEDER Locking Assemblies RfN 7012-IN . . . . . . . . . for shafts with inch-dimensions
RINGFEDER Locking Assemblies RfN 7013 . . . . . . . . . . . for higher demands to concentricity
RINGFEDER Locking Assemblies RfN 7013-IN . . . . . . . . . for shafts with inch-dimensions
RINGFEDER Locking Assemblies RfN 7014 . . . . . . . . . . . for extremely stressed shaft-hub connections
RINGFEDER Locking Assemblies RfN 7015 . . . . . . . . . . self-centering, for highest transmission values
as well as for the use in belt drums
RINGFEDER Locking Assemblies RfN 7110 . . . . . . . . . . compact dimensions, excellent centering ability
RINGFEDER Locking Elements RfN 8006 . . . . . . . . . . . . adaptable design for special requirements
RINGFEDER Shrink Discs . . . . . . . . . . . . . . . . . . . . . . . for external Clamping
RfN 4071 / 4091 / 4051 / 4073 / 4171
RINGFEDER Shaft Couplings . . . . . . . . . . . . . . . . . . . . . for an absulutly rigid connection of shafts
and high accuracy of alignment
Special designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . on request
Torque wrenches and accessories . . . . . . . . . . . . . . . . . . for correct tightening

Also available from RINGFEDER VBG GMBH:

Damping Elements, such as RINGFEDER Friction Springs designed to absorb high energies at relatively compact dimensions, DEFORM plus - non-reusable, one-hit shock absorbing elements, made of synthetic material or steel, DEFORM plus R - reuseable damping elements.
Trailer Couplings and accessories for road transport and special vehicles.

Certified in accordance with DIN EN ISO 9001 and DIN EN ISO 140001 and ISO TS 16949
RINGFEDER products are available from MARYLAND METRICS

2004-03 This publication may not be reproduced, either partly or wholly, without the source being quoted.

For shaft-hub connections we supply: