Worm Gearboxes

The Radicon Worm Gear range can come in Single Reduction and Double Reduction units which gives a high degree of common parts and interchange ability. Radicon worm gears are also available for Washdown Environments or can be Shaft Mounted and the Radicon heavy duty worm gears are ideal for Stirrer and Cooling Tower units.

Radicon Series A gearboxRadicon Worm Gearbox

Radicon Series A

Up to – 100kW / 8500 Nm

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Single Reduction Units (worm)

This fully metric range of units of 100, 125, 160 and 200 mm centres is based on a single universal case for each size, giving a high degree of common parts and interchangeability. Under-driven, over-driven and vertical types provide a choice of shaft arrangements in meeting the requirements of a wide variety of applications in the medium power range up to 140 kW.

All units are designed with hollow output bore, outputshaft can be fitted allowing handing to be changed without dismantling the unit.

Series A Mid Range gives a choice of 12 standard ratios from 5/1 to 70/1 and important features include high efficiencies and load carrying capacities combined with long life and reliability in service.

Double Reduction Units (worm/worm)

These units consist of a standard single reduction unit with a smaller shaft mounted unit fitted to the input shaft. The three smallest sizes are fitted with shaft mounted Series A Junior units whilst the size 2002 is fitted with a size 1002 (C07 when motorised). The range extends the ratios available up to the maximum of 4200/1 making them ideal for fitting to slow moving machinery (Ratios up to 14900/1 are available in size 2002 motorised. Consult our Application Engineers for details).

As with the single reduction units they are available in under-driven, overdriven and vertical types, foot mounting and shaft mounting.

Heavy Duty Stirrer Units

Based on the standard Series A Mid Range the Heavy Duty Stirrer Unit incorporates an extended bearing housing to accommodate a larger bottom bearing and increased shaft size, thereby enhancing the units capacity to absorb the high bending loads imposed during stirrer applications.

These units can be ordered with a dry-well option to minimise the risk of output shaft leakage.

Cooling Tower Fan Drives

Based on the standard Series A Mid Range the Cooling Tower Fan Drive incorporates an extended top bearing housing to accommodate the larger wheelshaft bearing whilst maintaining a compact drive.

Lengths of output shaft extensions are manufactured to clients requirements to suit fan hubs.

Lubrication is entirely contained. Gears and lower bearings dip in the oil bath whilst oil is pumped to the top wheelshaft bearing by means of a built-in mechanical oil pump.

Two oil seals are fitted on both the wheelshaft and wormshaft, the wheelshaft extension incorporating a grease chamber. All exposed parts other than the extensions are finished with corrosion resistant paint. Units are supplied with BSP plugs fitted to the oil filler, drain and ventilator points, suitable for connection to the outsides of towers. Where specified on the order we can supply the necessary piping complete with ventilator, combined dipstick and oil drain.

When selecting a unit, use the selection procedure as detailed on pages 10 – 11 and apply a service factor of 1.75

Enquiries should include full details of the duty required together with full information regarding ambient temperature at site and whether acids or abrasive solids are likely to be present in the air flow.


Series ER - Heavy Duty Worm Gear

Series ER – Heavy Duty Worm Gear

The ER Series of worm gear units are direct replacements for the David Brown (Radicon) Series A heavy duty worm gear units. All critical dimensions and product quality is the same and the ER heavy duty worm gear range is available in the following types:

  • Underdriven ER – U
  • Overdriven ER – O
  • Vertical ER – V



Series AJ - Junior Worm Gear

Series AJ – Junior Worm Gear

Our series A junior worm gear range is offered in unit sizes 280, 410, 510, 610, 730 and 860 based on a single universal case for each size, giving a high degree of common parts and interchange ability.




Series BS Compact Worm Gear (Benzlers)

Up to – 4kW / 315 Nm

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Benzler worm gears BS 40-71 have a symmetrical gear-housing manufactured in aluminium. BS 88 and 112 have a gearhousing of cast-iron.

The worm wheel is made of centrifugal cast tinbronze and the worm screw is case-hardened and ground.

All motor connections are according to IEC-standard and for BS 40-112 with elastic coupling. This means the following advantages:

  • The worm screw is mounted with two separate bearings and are not connected with the motor bearings. This means longer lifetime and a smoother drive
  • Soft start and stop with elastic coupling for size 40-112
  • No oil leakage in to the motor
  • Possibility to change motor without dismounting the gear
  • Any type of motor with IEC-flange can be used

The worm geared motor is available for mounting on a base, flange or torque arm and can be installed in any position.

The gear can be combined with Benzlers’ remaining range of helical and worm gears to provide very low output speeds. All data given in this catalogue applies to ABB standard motors and Benzlers brake motors.


The motorflanges up to IEC-size 112 are made of aluminium and are available in B5 and B14, larger motorflanges are made of cast-iron and available in B5. A finished bore shaft coupling is always delivered together with the motorflange.


The feet can be mounted without modification.

Output shaft

Single or double output shaft can be mounted into the hollow shaft. The output shafts are locked into position with keys and retaining rings. BS 88-112 has as standard execution, a single output shaft or a hollow shaft.

Output flange

An output flange can easily be mounted on to the gear. The BS 40-71 gear casing can also be mounted onto a wall or foundation and bolted through the 4 bolt holes in the gear casing.

Torque arm bracket

The hollow shaft gearboxes can be supplied with torque arm bracket and torque arm.


BS 88/112 have fan as an option.


BS40-71 is normally delivered without painting. BS 40-71 can be delivered according to environmental classification M2-M3. BS88-112 is normally delivered with standard paint, which is an alkyd paint in Benzler blue colour (RAL5015).