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Clutches and Gearboxes

Mechanically and hydraulically actuated over-centre clutches are available in two mounting styles, speed increasing or decreasing gearboxes, oil bath clutches.

Mechanically and hydraulically actuated over-centre clutches, gearboxes, oil bath clutches
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» 'BD' series for close couple to diesel engines with SAE style flywheel facility.

» 'BDS' for independent, in-line arrangements, capable of accepting high radial loads and transmitting powers of up to 850 kW as standard. Versions are also available to close couple hydraulic pumps to the clutch output shaft.

» 'RM' version gearboxes are specifically designed for close coupling to industrial diesel engines and are available in either speed increasing or speed reducing format.

Gearboxes can be supplied with output shaft either same or opposite rotation to input shaft. Input to the gearbox can be made either by rigid/flexible coupling or via a 'BD' series clutch.

Type BD clutches have been designed to mount onto any engine with flywheel and bellhousing conforming to SAE dimensions. These clutches consist of an overcentre clutch assembly mounted onto a tapered shaft carried on two bearings.

The pilot bearing is housed in the engine flywheel and the outer bearing serves to support the output shaft and is capable of withstanding radial loads as detailed within this catalogue.

For exceptionally high radial loads models BD290/150R, BD2200R and BD3300R are available with special heavy duty bearings.

Power is transmitted by clutch plates located within a driving ring bolted to the engine flywheel.
type BD clutch components, exploded diagram

The clutch mechanism is equipped with a unique automatic clutch adjustment device capable of compensating for reasonable clutch plate wear.

Type BDS clutch units provide a unique range of free-standing clutches intended for applications where engine mounting is not possible. BDS clutches consist of a BD type clutch but with a drive plate supported on the input shaft carried on two bearings in the independent bellhousing. The drive plate carries the driving ring and main shaft pilot bearing.
BDP and BDSP clutch units are constructed as per the standard type BD and BDS clutches, but offer a selection of hydraulic pump adaptors in place of output shaft.

Selection
BD clutches must initially be selected to match the available SAE flywheel and housing offered on the diesel prime mover. Subsequent study must be made to ensure that the clutch unit selected is capable of offering sufficient torque capacity to provide the service factor recommended for the application. Please note that the maximum torque figures published in our literature do not include a service factor.

Clutch selection must take the following into account:
» Type of prime mover.
» Inertia of machine to be driven.
» Peak torque requirement of machine.
» Number of clutch engagements per hour and duration of engagement.

The tables on page 4 of the clutches and gearboxes catalogue will assist with selection. Table A gives the service factor according to prime mover and application. Multiply input HP by this factor, and when applied to Table B, taking account of input RPM and the corrected input HP, the clutch selected must appear to the right of the convergence point.

Further information including dimensions, weight, torque, etc » pages 4 - 10 of on-line catalogue

If in doubt, contact jbj technical department, telephone: 01737 767493 or email: info@jbj.co.uk

BD and BDS clutches are available with hydraulic pump adaptor in place of output shaft on models BDP and BDSP. The pump adaptors take the same form as offered on the type AM multiple pump drive units, but the selection of adaptors may be restricted according to the clutch and pump combination planned. Further details are available upon request.


RM gearboxes consist of a 2-piece cast iron casing (*except RM20 units) with helical teeth, case hardened gears and shafts. Reverse rotation units have a primary gear on the input shaft driving directly onto the secondary gear powering the output shaft. Same rotation versions have an idler gear between primary and secondary gears.

There are 3 basic types of RM gearbox;
RM-GR models are for close coupling to diesel prime movers and have a choice of SAE housing and rigid or flexible couplings.
RM-BD models are similar to RM-GR but are fitted within an over-centre clutch in place of coupling.
RM-BDS models offer independent mount units with over-centre clutch.

Selection
The power and torque capacity of the unit will vary according to the selected ratio. The published maximum torque figure is the theoretical permissible limit for operation during a 5000 hour period at an input speed of 2000 rpm. The maximum engine kW indicates the power that may be transmitted under normal conditions without an oil cooling system. These limits give merely an indication and ignore such factors as ambient temperature, air circulation, application, etc. RM unit selection should be made by taking input torque, and by multiplying it by the service factor applicable to the application.
Examples of service factors are shown below.

Service Factors
1 - Light duty : centrifugal pumps, fans, etc.
1.2 - Medium duty : 4 cylinder compressors, conveyors, hydraulic pumps, marine applications.
1.5 - Heavy duty : 2 cylinder compressors, presses, cement mixers.
2 - Very heavy duty : 1 cylinder compressors, mills.

The above factors apply only to RM gearbox units. For clutch/gearbox combinations study also the clutch service factor and maximum power/torque limitation.
For assistance contact jbj technical department, telephone: 01737 767493 or email: info@jbj.co.uk

Installation
The RM-GR & RM-BD units have been specially designed for close coupling to industrial diesel engines and consequently are constructed with a single support bearing on the input shaft and must therefore utilise the pilot bearing available on most engines. Pilot bearings can be supplied if required.

When installing an RM-BDS unit take care to mount unit with shaft axis horizontal and on common base with prime mover. Satisfactory alignment between drive coupling and input shaft should be achieved in order to avoid axial and radial loads on the input shaft.

RM units may be ordered with output shaft rotated through various positions to suit customer applications.
Please contact jbj technical department, telephone: 01737 767493 or email: info@jbj.co.uk for confirmation.

Lubrication
RM units are supplied without oil. Before use fill to maximum mark on dipstick. EP90 gear oil such as BP ENERGOL CS150 is recommended. The lubricant must be replaced after the first 100 hours use. Subsequent oil changes should be made every 1000 hours dependent upon the application, or every 12 months, whichever is the sooner.

Efficiency
Reverse rotation - RM “D” units offer 97%
Same rotation - RM “S” units offer 95%

Further information including dimensions, weight, torque, etc » pages 11 - 15 of this catalogue

Oil Bath Clutches are free standing clutches of the multiple plate, oil bath type. These clutches are particularly suited to arduous applications and are capable of withstanding high radial loads.

The PFI 60 and PFI 120 are manufactured with input and output shafts. The PFI 60P and PFI120P are intended for hydraulic pump direct connection with the same pump adaptor flanges and couplings as on AM 230 - 450 pump drives which means the possibility to fit a large number of pumps with standard components.

Further information including dimensions, weight, torque, etc » pages 1 - 3 of this catalogue


» Link to view the wider range of power take-off units «
Specification of clutches & gearboxes found in this on-line » catalogue « link
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