British Anzani ..How it works

These British Anzani Iron Horses were powered by a single cylinder,air cooled, four stroke, petrol, JAP 5 engine.

For JAP engine info , click here :

The engine is started with a handle

It has a centrifugal clutch so that as the engine revs up the clutch gradually take up the drive.

It is fitted with a Ford gearbox, which has`3 forward and a Reverse gear.

Output power is transmitted from the gearbox to a worm drive onto a lateral drive shaft. This drive shaft has a dog clutch on either side , so that power to either side can be disengaged . A drive chain on either side transmits power to each wheel.

( Phil Harding has advertised replacement chains in The Cultivator magazine. 0127638563 , Camberley , Sutrrey )

The dog clutches are operated on ether side by the handlebar levers to allow one wheel to disengage to facilitate short turning. This feature was referred to as “Power Steering ” , not quite as smooth as what we would expect from a power steering feature today. During normal operation, power is transmitted continuously to both wheels, so it is not possible for one wheel to slip or spin independently.

The engine output shaft is fitted with this clutch assembly. The centrifugal clutch consists of 3 offset drive pads, each with a retaining spring. As the engine revs increase, the resultant centrifugal force, forces these 3 drive pads to pivot outwards as the outward centrifugal force overcomes that of the retaining springs. This allows these drive pads to engage with the gearbox input shaft hub. When the engine revs are reduced sufficiently, the centrifugal force reduces and the drive is disengaged.

The engine revs are easily controlled by a finger tip throttle located on the handlebar.

The centrifugal clutch drive pads as very similar to car or bike drum brake pads, so it is similarly possible to have the worn friction pads removed and replaced with new ones.

Here , with the engine removed, it is possible to see the gearbox input drive hub , inside which the centrifugal clutch operates.

Here you can see the gearbox input shaft with the clutch drive hub removed.

This is the common chassis onto which the main components are bolted.

This drawbar assembly is bolted onto the rear of the chassis, to allow fitting of some of the tools (including the plough) Note that there are two draw pin locations… at the center and one on the left.

It is fitted with a Ford syncromesh gearbox which has 3 forward and a reverse gear. The engine must be running / ticking over slowly to allow a gear to be selected easily. A linkage runs from the gear selector on top of the gearbox back to the handlebars to allow easy gear selection when in use.

This is the power take off , either suitable for a flat drive belt in some applications or for fitting of a V- Belt pulley to drive auxiliary equipment. From Shane Hall’s FB page, you can see a bench saw being driven by this 1952 Anzani. This drive is driven directly from the gearbox and normally rotates when the wheels rotate. When using it alone, it is possible to lock both wheel drive dog clutches in their disengaged position, by fitting a pin through both rods that extend sideways from the steering box.

Some tractors are fitted with an optional hand brake, with the ratchet lever positioned on the RHS Handle bar. Engaging the lever tightens a brake band at the power take off. The effectiveness of this brake can be improved by rotating the eccentric bolt when the end of the brake band is secured, seen here on the left side of photo. This feature added £ 3 to the price of the tractor. It can be too easy to forget to disengage this hand brake before moving away.

In order to help counterbalance the tractor and help with traction when ploughing, the addition of a front weight is recommended. Back in the day , it was possible to buy a steel weight which fitted inside the front bumper ring It cost £ 1/10 back in the day. . Phil Harding also made a concrete weight for this space. To get the required weight, the concrete weight has to be quite deep. When reversing with the plough, you will have the handlebars raised quite high so that the plough clears the ground, but this can result in the weight scraping on the ground as you reverse.

From post on VHGMC Ritual , Phil Harding 2009

I had this weight cut from 60mm plate steel. It weighs 29KG and makes a huge difference when handling the tractor with plough at the headlands and especially when loading up ramps onto a trailer. I created this paper template to bring to a local engineering company to have it made.

A screw jack stand placed on the front of the tractor chassis is a clever addition, as with the plough removed it is normally unbalanced and will topple forward. This jack would be very useful, so I hope to add one to my tractor at some point.

From Kevin Castles FB post.

Many have a toolbox fitted to the upper handlebars. The original toolbox , costing £ xx when purchased with the tractor had the above plate secured to the toolbox lid.

The British Anzani Iron Horse was fitted with a hinged hood cover. When opened up, it could be supported with the stay provided. Most of the hoods have 3 vent louvres on either side , while some have 4 such louvres. I would be interested to learn if there is anything on how that was. The hoods of many of the tractors that were abandoned behind ditches suffered heavy corrosion and some are beyond repair. Mick Green has some replacement fiberglass hoods now available