David Brown Cab Development & Engineering

The purpose of the tractor cab was initially to protect the operator from the weather, but improvements were later made so that it also protected the driver from serious injury in the event of a rollover or impact. As design improved, and the operator began to demand a better working environment, the cabs also began to give greater protection from noise and dust within a completely separate and sealed environment. The concept of keeping the driver protected from the elements was not new; indeed David Brown had been one of the first manufacturers to adopt this idea as standard.

The best-known form of protection from the weather had been provided in the famous cowl (or scuttle) that appeared on the VAK and Cropmaster model. It is known that Her Majesty Queen Elizabeth (the Queen Mother) really appreciated this feature on the VAK1 that she used in Windsor Great Park during the ’Dig for Victory’ campaign in World War 2. Other manufacturers gave little thought to driver comfort, but much more was required than the simple cowl, which only offered limited protection to the driver’s legs and lower body.

Soon after the war Browns began to offer a ’strip down cab’ and the first known photograph shows one of these on a VAK1A in 1947, but we are not sure when it became widely available. The cabs were not widely appreciated, and the salesmen reported that customers disliked using them in all but the worst weather. They were noisy, vibrated a great deal, and restricted the operator’s vision and, if anything, the draughts that came in were worse than the wind. Therefore, the emphasis on these early cabs was to design them for easy removal as soon as the weather improved.

When the Selectamatic range was introduced in October 1965 a factory-fitted cab was not available, and all publicity shots showed the driver working in good weather; obviously a cab was only for wimps! However, the after-sales experience showed a different situation and a number of them were retrospectively fitted with various cabs that kept the worst of the weather off the driver.

Robin Healy from Spofforth writes ’by the early 1960s the days of horse ploughing were well and truly over in the Yorkshire Dales, and most farmers were now running at least one tractor and a Land Rover. We had been selling very well into this market until Massey Ferguson began offering a cab made by Scottish Aviation. It was reasonably weather tight and had good rubber seals round the doors, and a tiedown canvas curtain at the back. Once the upland farmers saw it, they began buying them in good numbers. This was reported back to Meltham Mills and one of these cabs was ”acquired” for inspection. Someone obviously decided that a go could be made of a DB cab and soon we were telling our customers that we could supply them with a better tractor and a better cab. Several types were fitted but the one I remember best was by Lambourne. This ”after market” was entirely different to the production run, where cabs were still deemed as ”non-essential” but official sanction was given for “dealer-fitted” cabs.’

These cabs had a frame, windscreen surround and doors made from metal, but they had flexible side screens, roof and roll down rear panel. Contractors and drivers who were often on their tractor all day in a biting wind appreciated this improvement, but others found the reduced visibility disconcerting as they were never in the seat long enough to get used to it. There were still numerous holes, which could cause some cold draughts, but the farmers often blocked these up with Hessian sacks. The driver benefited with heat from the transmission once it warmed up, but for a long time there was a real resistance towards the cabs, however, things were soon to change!

Towards the end of the 1960s, an increasing number of farm accidents were being recorded where tractors had rolled over. This prompted legislation requiring all new British tractors to be fitted with safety cabs or frames from September 1970 onwards, but, before the law came in, we had already begun offering the ’Sta-Dri’ cab as a factory-fitted option. It had a steel box frame, which bolted rigidly to the rear axle and down the front of the doors to the main frame. The windscreen and doors on this cab were rigid, but the rear only had a roll-down screen. The roof and side windows were optionally rigid or flexible cladding. A drawback with this early cab was the noise level for the driver, which was high enough to cause damage to the driver’s hearing unless ear protectors were worn.

The late Robin Kedward of Monmouth, who used to work for the agricultural dealers Taylor & Jones, remembered fitting many ‘Sta-Dri’ cabs, some in the workshop and some on the farm. Later these cabs were supplied from the factory at Bristol with the name ’Victor’ over the windscreen. Robin recalled that the cost to retrofit the ’Sta-dri’ was about £130 in the early 1970s, but the farmer would receive £15 for his old shell fenders if they were ‘in good order. Other ’after market’ manufacturers also produced safety cabs to fit DB tractors, including Lambourne, Sekura, Fritzmeyer and Duncan. The ’Sta-dri’ cab was initially assembled and fitted to the tractors in S Block, which was just off Huddersfield Road, Meltham Mills. Incidentally, this building later became home to the apprentice training school, where i spent my first year. It also housed the Demonstration Department, which provided the keen apprentice with a wealth of tractors and equipment to view.

By 1972 David Brown had designed its very own safety frame and cab named the weather frame. This was mounted on the mudguards only, which were in turn reinforced and fixed to the rear axlecasing. The mudguards were wider and went further towards the rear, thereby reducing the amount of mud being thrown from the rear wheels onto the rear axle. This was an improvement to what had been a problem with the ’Sta-dri’ cab, which finished rather abruptly at the rear. The late Tom Lazenby wrote; ’the Sta-dri was a bit of a beggar, because you often found that mud was being thrown into the back of the cab, and we had a lot of problems with it! But it wasn’t only mud that caused trouble, and in Lincolnshire we found that fine soil particles would whip around the cab during dry weather, abrading the paintwork and windows. The worst problem was dust getting in the driver’s eyes, and all we could do was supply goggles. We needed a cab that met the legalisation, but one that could be either totally enclosed in bad weather or open in good.

‘The best example i could think of was Scandinavia where we sold a lot of tractors, and where there were very extreme weather conditions. So after visiting our main dealers there, I wrote a report on the problem and suggested that we could employ a roofed roll frame (like a bandstand), which could be fitted with cladding as required.’

The result was the weather frame, which was taller than the ’Sta-dri’ cab but also had the effect of reducing the noise somewhat the roof also absorbed some noise. Some farmers were irked that they had to buy a tractor with a cab, and for others the added costs were a burden that they were reluctant to accept. Accordingly Browns opted to offer the basic safety frame and roof letting customers upgrade as required; metal doors and cladding cost £185 in 1975, whilst the arctic version cost £310. Lambourne also did a cladding kit for the ’after market’.

The higher cab had its drawbacks though, and Hughie Cartwright relates that some farmers in South Yorkshire switched to other manufacturers due to some not being able to access their older sheds with lower doorways. To resolve this problem Browns later offered a low profile cab (with optional cladding kit), which replaced the roof of the weather frame With a canvas cover and flexible side windows.

In June 1976, it became a legal requirement for all new agricultural tractors sold in the UK to have an in-cab maximum noise level of 90 decibels. The solution to this was the development of the Q-cab, and I remember seeing the first of these on a tractor outside S block parked next to a tractor fitted with a weather frame cab. The Q-cab was a complete pod manufactured at Leigh, but completed on a sub-assembly line at Meltham Mills before being lifted onto the tractor on the main assembly line in R Block. It was supported on four rubber mountings for noise and vibration insulation.

It was complete with a fuel tank, and had a raised floor level with sound insulation and rubber matting on a virtually flat floor. The driver sat higher than in the old cab, gaining better all round visibility, yet the overall height was not increased. A small slope at the cab end ofthe bonnet covered the fuel tank, which protruded from the cab assembly, this tended to make the bonnet on the 12 and 14 series tractors look shorter than previously. The steering was hydrostatic, and the clutch and brakes were hydraulically operated. The new heater was found to be essential in cold weather, as warmth was no longer felt from the transmission.

The new cab was first shown at the Smithfield Show in 1975 and it became available in the New Year as an alternative to the weather frame cab, which was phased out prior to June 1976. A radio became an option, as it could actually be heard in the quieter tractor cab. The OECD/NlAE rating for the 1210/12 was 84dBA. By 1978 the Q-cab was improved even further and called the VQ. The overhanging rear of the cab was now vertical as were the rear edge of the doors, this made access a little easier and reduced the possibility of some linkage-mounted equipment fouling the cab rear. Natural ventilation was then provided by one opening side window instead of an opening door window. At this time a De-Luxe cab became available as an option, and this gave improved visibility. Made by Sekura at Barnsley, this cab featured a flat floor, padded fenders and – for the first time on a David Brown – an escape hatch in the roof. However, this safety feature was probably used more for added ventilation than its intended purpose! The side windows were sliding openers as were the lower rear windows but the large upper rear window was opened by gas struts. Following this a low profile Sekura cab was made for 885, 990, 995 and 996 tractors.

Most tractors for the overseas market went as non-cab versions, and, where cabs were needed abroad, they were fitted to appropriate local designs. However, large numbers of cabs were supplied to the American and Canadian market in ’kit form’. A cab testing area was built in the old railway yard at the rear of Scar Bottom Mills. This could be used for crush and impact testing of the cab safety frames, the glass would be removed for safety of test personnel, the tractor was firmly fixed down and after the tests measurements of any deformity would be recorded.

However, one incident of cab testing in the Field Test Department happened rather suddenly and was unplanned. A new 1410 4WD fitted with De-luxe Sekura cab and Carraro front axle had been prepared for field-testing. The driver, Derek Nobles, was eagerly awaiting going out into the field, but the tractor was ‘borrowed’ by one of the technicians to nip down to Meltham Mills on an errand. He decided to return on the ’Coalgates’, an old cobbled road built to carry coal from the railway yard down to Meltham Mills, which ran for some distance alongside Hall Beck. As the tractor ran along the track, it left the road and ploughed down the embankment hitting a large tree. This stopped its progress dead, and it rolled into the river. The technician was unhurt and walked back to report the incident to the Field Test Manager, Derrick Smith. Needless to say, the tractor did not make it into the field that day!

The year 1979 saw the public release of the 90 series David Brown tractors at the Smithfield show. The cab used on this range was of Sekura manufacture, but its design was a joint project between Sekura and DB. This cab remained in use right up to the last 94 series tractor leaving Meltham, although some modifications and improvements were made over its eight-year life span. This cab actually looked part of the tractor, and not just added on! Indeed it was specifically designed to look like part of the tractor as a whole, and on release it was widely praised for its elegance. For the first time the fuel tank was not in front of the cab but below it, which in turn allowed for wider doors that were hinged to the rear allowing very easy access up wider steps.

Visibility was excellent, and the Grammer seat was adjustable to suit the height and weight of the driver. Both side windows opened for ventilation, as did the rear window, which was supported on gas struts like the roof hatch. A radio and rear floodlight switch was fitted in the cab roof. An excellent heater was also fitted as standard and a three-speed fan would how air down to the floor, through circular vents in the dash or onto the windscreen. This was much appreciated by the drivers during the cold months of the year.

There were shortcomings with these cabs in hot weather when it was found that the heater could not be turned off and warm air continued to be blown into the cab, the opening windows and roof hatch proved ineffective in cooling the interior. A service kit, which included insulation for the Orbitrol unit, was supplied to those who complained. As this unit was mounted under the dash and got very hot in use, it was thought to be contributing to the temperature problems. A tap was also fitted on the engine in addition to the cable-operated tap in the cab, whilst an insulation sheet was fixed to the air-filter housing in front of the cab.

Yet all these modifications proved ineffectual, and the only way around the problem seemed to be either driving with the doors open or removing them. It was then found that the heat was coming with air from the engine radiator and the absence of a fuel tank in front of the cab meant that the full blast hit the cab air intake. But apart from air conditioning the only cure was to fit a pusher fan on the engine, and that created further problems in other areas. The cab on the 94 series had a re-directed air intake and an underfloor Orbitrol unit so it reverted to puller fan but, without air conditioning, the problem still existed. Other annoying problems with this cab included dash-mounted throttle control pins sheering off and the driver’s knee constantly switching on the indicators. It was also possible to move the three-way hydraulic valve by inadvertently sitting on the lever.

When the 94 series was introduced a number of improvements and changes were made. Most visible was the change in the interior colour from black to grey and the alteration of the front sidelight and indicator clusters. An external grab handle was fitted for ease of entry. Cab air was now drawn from the right hand side of the bonnet as opposed to from under the windscreen. First introduced on the 169OT, the majority of controls were grouped in a flat-topped deck console to the right of the driver. This was named ‘Human Engineering’ as the driver could operate these controls without changing his body posture. Another welcome feature was the fact that the cabs could be split for removal to facilitate entry into low buildings.

The Orbitrol unit was repositioned under the cab floor; this was considered to be highly essential for, as well as removing a heat source from the cab, the unit was inherently noisy. As a result the cab environment was much quieter! One problem in this arrangement was that, if there was any misalignment in the shaft connecting the steering column to the Orbitrol unit, it could work its way out and thus result in a loss of steering. David Brown later started to produce these cabs at its Leigh factory, and it is still felt by many drivers to be the best.













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