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Tyre Couplings

Can be produced in accordance with the requirements of regulation 94/9/CE (ATEX 95) of a group ll device, category 2G or 2D (zone 1) and temperature class T4.

With a flexible body that compensates misalignment and protects other components in the transmission system. These torsionally flexible couplings can be produced in accordance with
the requirements of regulation 94/9/CE (ATEX 95) of a group ll device, category 2G or 2D (zone 1)
and temperature class T4.
ATEX mechanical power transmission tyre couplings from jbj Techniques Limited
The fundamental element of the tyre coupling is a neoprene rubber tyre reinforced with a synthetic mesh. It adapts itself to the working conditions, absorbing axial, radial, angular and torsional misalignments and prevents vibration via the transmission to the machines to which they are coupled. It compensates the defect of angular misalignments to 3º, radial misalignment by 4 mm, and axial misalignment of 6 mm.

These mechanical power transmission tyre couplings cushion the effects of overloading, absorb vibrations, reducing noise and protecting the machine from the destructive effects of vibration.

There is no metal to metal contact between the shafts and the hubs are completely isolated. No lubrication is needed.

Replacement: Easy and practical. There is no need to move the motor or other components within the transmission. It is sufficient to release the axial screws, so freeing the coupling. The result is better running of the machine and a longer life for the whole installation.
tyre coupling alignment compensation properties
Torsion & vibration

ONE of the most interesting characteristics of the trye coupling is the very simple way in which the rubber tyre couples. The rubber tyres are set on the coupling's hub and are fixed by means of fastening rings (2) and screws (4). There is no need to carry-out a detailed setting of the machines to be coupled and the slight displacements of their shafts can be quite easily disregarded.

The tyre coupling is made up of just a few simple components that form the coupling, and is extremely easy to assemble. The coupling's rubber tyre is split radially at one point on its periphery (the surfaces of the cut are vulcanized so as to avoid the folds of the mesh absorbing humidity). This cut allows the rubber tyre to be replaced without moving the machines. To do this, it is sufficient to loosen the screws (4) of the two fastening rings (2), remove the worn tyre and replace it with the new one. In this way. the coupling is never out of service for a long period of time. even when there is only a very limited space available in which to effect the changeover.

Coupling specification needs to take into account that the maximum torque to be transmitted is not exceeded.

cross section of tyre coupling from jbj Techniques
These tyre couplings are used for individual roller drives in which it is advisable to avoid open reduction gearing and to use a highly flexible, slack free coupling.

There are a number of important features for individual drive of a roller through a highly flexible, slack free tyre coupling and roller table geared motor.

» The intermediate coupling prevents direct heat conduction from the roller to the gearbox and to the motor so that neither gearbox lubrication or motor isolation are adversely affected.

» Most of the vibration and shock produced when the conveyed material runs on to the roller, and especially when it is laid on it is isolated from the drive.

» Sagging of the roller, which can often be seen when working conditions become heavy, has no adverse effect on the gearing.

Couplings: In order to determine the size of coupling to be used the following formula should be applied:

Nominal Torque = [Driving-motor power (hp) ÷ Minimum speed of the connected axles (rpm)] x  7017 x k

Nominal Torque = [Driving-motor power (kw) ÷ Minimum speed of the connected axles (rpm)] x 9549 x k
The value obtained on applying the formula should be less than or equal to that indicated in the tables of sizes and powers that refer to the corresponding coupling in the column "nominal torque".

Value of co-efficient

tyre coupling data table for values of co-efficient
The values indicated in the above table are by no means applicable to every case. If, for example, one of the machines to be coupled displays such a degree of irregularity that it is judged necessary to carry-out technical investigations of the oscillations, then it is recommended to proceed to the selection of the multiplying co-efficient using the enclosed questionnaire.

The following groups apply to the machines being driven:
K-coefficient calculation guidance for different groups of machines.

1. Continual load machines: Generators (electrogenetic group). Conveyor belts. Small hoisting equipment of up to six starts per hour. Low power machinery for working wood. Small fans. Small machines of which principal movement is rotation. Small centrifugal pumps.

2. Variable load machines: Small hoists. Generators. Winches. Hoisting equipment of up to 120 starts per hour. Conveyor chains. Crane movement mechanism. Sand blast equipment. Textile machinery. Transmissions. Conveyors Turbo blowers (gas blowers: compressors). Fans. Machine tools in which main movement is rotation. Large winches. Centrifugal pumps.

3. Normal size to heavy machinery: Heavy hoists. Revolving ovens. Tannin barrels. Cylinder grinders. Refrigerating drums Continuous Ring Looms. Mechanical mixers. Cutters. Sharpening machines. Washing machines. Looms. Brick presses. Fans Hoisting equipment of up to 300 starts per hour. Translation mechanism.

4. Heavy machinery: Dredge control mechanism. Briquette presses. Rubber rollers. Ventilators for mines. Machinery for sand papering wood. Sand and paper grinders. Pumps with immersible piston. Cleaning drums. Machinery of oscillating movement. Compound grinders. Cement grinders. Draw benches. Hoisting mechanisms. Hoisting equipment of more than 300 starts per hour.

5. Heavy machinery: of variable energy consumption: Large drilling installations. Machinery for glossing sheets of paper. Horizontal and reciprocating vertical saws. Presses. Paper calenders. Roller trains for laminators. Drier rollers. Small rollers for metals Centrifuges. Roller equipment for paper.

Example: The elevator bucket is driven by a motor of 16 kW; n=1.450 rpm., by means of a reducer whose outlet axle rotates at a speed of n= 180 rpm. The motor and reducer are protected by a UNE-FLEX flexible axle coupling.


N = 16 kW
n = 1450 rpm

M = N kW x 9549 x k

Elevator buckets figure in group 2 of the classification. under "variable load machinery". The multiplying co-efficient k = 1,5 figures in the k value table under heading 2 and in the classification of machines driven by "electric motor".

M = 16 x 9549 x 1.5 = 1273 Nm

Then, according to the power table the appropriate coupling for a torque of 158 Nm is model M-5.


N = 16 kW
n = 180 rpm

M = N kW x 9549 x k

M = 16 x 9549 x 1.5 = 1273 Nm

Then, according to the power table. the appropriate coupling for a torque of 1273 Nm. is model M-9.

Note: to carry out the correct selection of a coupling, an indication of power and speed is generally suficient. It is however, better to have the following information as well:


1. Kind of motor (make, type, running factor in ED)
2. Power of motor: N......kW.
   Speed: n.......rpm
3. Input and output axles diameter.
4. Couple of start of the motor: C = Nm
5. Type of machine to be driven.
6. Whether operation is continuous or intermittent.
7. Number of starts per hour.
8. Whether operation conditions are uniform. irregular or special, and if there is any running change.

» Coupling Assembly

ATEX certificated tyre coupling assembly diagram

1. Join the two halves of the coupling and pressure rings to the pivots of the axles.

2. Draw back the machine with the two halves until the N measurement, as indicated in the table, is reached.

3. Align the axles until distance N between the two halves of the coupling is reached. Normally, it is sufficient to carryout adjustments with simple measuring tools since small inaccuracies in the coupling assembly can be permitted. For quick turning couplings, it is recommended to adjust more precisely with a template, since, if this is not done, the subsequent knocking could harm the working-life of the tyres. As for axle couplings with safety mortises or grips, the two halves of the coupling should be assembled in such a way that the mortise surfaces of both halves form a 45°angle.

4. The cut tyres (3) are set on the coupling halves so that the edges of the cut form a channel of 2-10 mm., according to coupling size. For large couplings, before tightening the pressure rings, tighten the rubber tyre using clamp bands.

5. Screw down the pressure rings so that at the same time two diametrically opposed screws are tightened and pressure is put on the fitted rubber tyre until its thickness is 2/3 rds that of its original thickness.

Replacement of tyres:

1. Loosen pressure ring screws until tyres is freed.
2. Remove worn tyre.
3. Replace it with new tyre.
4. Tighten screws.

We ask you to indicate tyre number, clearly marked on tyres, when ordering replacements.

cross section of tyre coupling from jbj Techniques
tyre coupling tightening torques data table

» Damping Isolation - Dynamic Torsional Stiffness

Damping Isolation - Dynamic Torsional Stiffness graph for tyre couplings

According to the above mentioned the isolation will grow when the dynamic torsional stiffness decreases, that is, when the torsion angle grows.

Varying the torsional stiffness will vary the % of isolation.

data table of torsional stiffness for tyre couplings type 'R'data table of torsional stiffness for tyre couplings type 'X'data table of torsional stiffness for tyre couplings type 'R/X'
Industry Sectors

Tyre couplings are used in many sectors where transmission from a motor to the connected machine is needed. Iron and steel industry, shipbuilding, compressors, mining industry, paper manufacturing machinery, cement manufacturing installations, pump installations, current generators and hoisting applications for instance.
Specification of tyre couplings found in this on-line » catalogue « link

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