Line production - from Station to Station

Richard Comelyin Machinery & Mechanics

In this, the third article in the series, Richard Comely and Lee Kristensen of Ransomes Jacobsen look, in detail, at the production of a Jacobsen GP400 ride-on greens mower.

On this particular production line, there are ten stations in the build process and the functions that happen on each are explained

Station 1 - Engine, Swing out arm, rear wheel yoke

The mower is delivered to the production line from the paint shop on a bespoke trolley and it stays on this as it travels the length of the line.

The first job is to prepare the engine and then insert it into the chassis. The GP400 can be fitted with either an 18hp Briggs & Stratton petrol engine, normally for export to the USA, or an 18hp Kubota diesel engine, the more common power source for machines in the UK, Europe and most other countries world-wide.

Both engines are fitted with their mounting brackets, main hydraulic pump and exhaust unit at the side of the line before being hoisted and positioned in the chassis.

The rear wheel steering yoke is bolted into position and the swing-out arm for the rear cutting unit, a patented design unique to Jacobsen greens mowers, is fitted.

Station 2 - Backlap valve block, cutting unit lift-drive valve block, rigid pipelines

Here, we begin to fit some of the main and ancillary hydraulic components. The first item to be fitted at station 2 is the backlap valve block.

Once fixed into position, flexible hydraulic hoses are attached and the hydraulic couplings hand tightened and a coloured line drawn vertically on both parts of the coupling. This is then tightened using a torque wrench and the coloured line becomes broken and offset showing that the coupling has been torqued correctly.

The colour coding is unique to the assembly technician and forms part of the quality checking system.

If a component is found to be incorrectly assembled, and there is a consistent colour present in the component marking, the technician can undergo further training to alleviate the problem.

Next, the valve block which controls the cutting unit lift and drive functions is fitted and we insert the rigid pre-bent pipework that connects these two components.

Station 3 - Wheel motors, hubs, brakes, rigid pipelines, handbrake

This station sees the rudimentary wheel and braking system added to the mower.

The wheel motor is bolted onto the chassis and the wheel hub, including the brakes, is attached to the motor.

More rigid pipework connects the wheel motors to the main hydraulic system.

This station is completed with the addition of the handbrake cable and mechanism.

Station 4 - Steering arm, steering flexible hoses, hydraulic oil filter

The mower now has the steering arm fitted, along with the steering wheel and, in this case, an additional paddle on the steering column for lifting the cutting units.

This is a special build requirement, so attached to the lift arm is a set of work instructions, which provide the assembly technician with details of how to fit the paddle.

The hydraulic oil filter is prepared on the workbench adjacent to Station 4, the hydraulic fittings torqued to the correct newton metres (nm) and the unit fitted into position.

Station 5 - Lift arms, lift rams, associated flexible hose

At Station 5, we see the fitting of the lift arms and hydraulic rams that actuate the lifting and lowering of the cutting units on the completed machine, along with flexible hoses that connect back along the machine to the associated valve block.

Station 6 - Wiring loom, control console, throttle cable

The control console is sub-assembled on a bench alongside Station 6 with the control unit mounted into its frame, the control fascia is then attached to the top of the frame and the wiring loom and fuses boxes attached to the various switches and joystick.

The throttle cable is then run to the back to be connected to the engine.

Note that the control console cover is left off after installation. This is because, at a later date in the test procedures, the technician may have to gain access to the controller for remedial work. It is much easier with the cover off!

Station 7 - Radiator, oil cooler sub-assembly and fitting

Fitting the cooling system begins with the sub-assembly of the radiator and oil cooler on the workbench alongside this station.

Once assembled, this is then fitted to the chassis, the bug screen inserted, the protective outer casing and radiator hoses attached. The final job at this station is to attach the air filter.

Station 8 - Fuel and hydraulic tanks, fuel line, major flexible hoses to main pumps

The fuel and hydraulic tanks on the GP400 look like a one-piece unit, but they comprise of two separate tanks that appear as one. These are assembled on a jig beside the production line, bolted to a base plate and the fuel pump, fuel filter and rigid fuel lines fixed into position.

Once assembled, it is lifted and bolted into position on hinges on the chassis. Finally, the flexible hydraulic hoses are fitted to the hydraulic tank.

Station 9 - Seat mounting

We are now very close to having a complete mower. First, we attach a hinged mounting plate and then bolt the Grammer air suspension seat to it.

This is a high quality seat that provides excellent comfort for the operator. It can be adjusted for the weight of the operator and has an adjustable backrest for added support.

Station 10 - Footplates, toolbox, battery, step, pedal and throttle cable, wheels

Station 10 is the final step in the build process.

We begin by inserting the battery tray, fixing the battery into position and fitting the cover. The rear axle and wheel hub is assembled and fitted to the rear wheel yoke, which was attached to the machine back at Station 1.

Sub-assembly of the reel motors takes place on the adjacent bench and they are then attached by flexible hoses to the valve block on the machine. The tool box and small access step are added, the operator's footplate is bolted into position and the accelerator pedal attached.

Finally, all three tyres are fitted to their relevant wheel hubs and the mower is complete.

Final Test

In this area, the mower is subjected to extensive testing of all the primary and secondary functions that it will have to perform.

It is placed on a rolling road to ensure that the traction motors function correctly, the cutting unit lift and lower controls are checked as is the cylinder rotation and the backlap feature. All the electrical and hydraulic circuits are tested, as are the safety switches to ensure functionality.

Once these tests are completed, which takes up to two hours, the mower is driven over to our dedicated test area, where mow and transport speeds are set, the turning circle is checked and a hill test ensures that the handbrake is functioning correctly.

Finally, the machine is driven back into the factory for a concluding leak test. It is hoisted on a ramp and checked with a UV lamp to see if any hydraulic oil leaks are visible. The hydraulic fluid has a UV reactive dye in it, which enables any leaks to be spotted easily.

If there are any build issues following this final test, the machine will be quarantined and remedial action taken to rectify the problem.

Usually, all that remains to be done is to fit the control console cover and ship the machine to the warehouse in readiness for despatch to the end-user.

In the previous features, we looked at the concept and design process, the manufacturing processes of the various components and, in this article, we have seen how a mower is manufactured as it progresses along one of our production lines.

The next article will look at what happens once the mower is built, how it is marketed, delivered and finally installed with the end user.

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Machinery & mechanics