The Friends of Ferguson Heritage Ltd. - Some Ferguson System Patents
The Ferguson System is not covered by a single patent, but by
many which date from 1917 to 1939. Many owed a great deal to
other members of the team, particularly Willie Sands, but it was
always Ferguson's vision which directed them towards specific
engineering solutions to a problem.
The following list of patents is not exhaustive- others relate
to reversible ploughs, cultivators, and farm transport for
instance; but it does indicate the thinking behind the system and
the evolution of it over a period of time.
12.09.17 Patent No.119883
Arrangement for direct hitching and controlling plough
including the first top link.
01.02.18 Patent No. 122703
Improvements to above. This is now known as the "Belfast"
plough hitch. Transfers tractor weight to plough to
15.12.19 Patent No. 160248
The two point linkage or "Duplex" hitch via an
upper and lower link set to converge to effect line of
draft forward of rear axle- the depth being controlled by
the varying length of the upper link. This is the first 'virtual
hitch point' system and also incorporates the first
partial overload release by weight transfer.
28.05.21 Patent No. 186172
As above, but with a depth wheel.
03.11.21 Patent No. 195421
A modification to 160248 allowing draft to balance
penetration via a spring mechanism.
11.12.23 Patent No. 226033
The definitive version of 160248 'Duplex' hitch which
employs automatic mechanical depth control via a slipper
in furrow bottom linked to a linkage. Acheived full
weight transfer while retaining safety features of the
12.02.25 Patent No. 253566
The Master Patent- incorporating the principal of draft
control whereby the depth of a ground engaging implement
is automatically controlled by reference to the effort or
draft needed to pull it. The linkage movement is effected
by electric, mechanical or hydraulic device. The patent
also covers draft control by means of the tractor's
03.07.28 Patent No. 320084
The next dimension to No. 160248, with converging three
point linkage together with front furrow width control
via a cranked cross shaft.
03.07.33 Patent No. 421983 Improved efficiency tractor transmission using
internally toothed ring gear reduction- as featured on
the Black Tractor and the Model 'A' , together with PTO
driven from final drive placed centrally over drawbar
plate; a belt pulley drive; and internally mounted dual
ram draft control using the system outlined in the Master
05.02.36 Patent No. 470069 A simple 'flow on demand' system, acheiving
hydraulic draught control by placing the control valve on
the suction side of an oil immersed pump to avoid
aeration and heating of oil.
05.02.37 Patent No. 470087 A development of the Master Patent and Patent No.
470069 which incorporates automatic release of hydraulic
pressure to protect the implement on hitting an
05.02.?? Patent No. 471515 Check chains/ anti-sway blocks for three point
linkage that allows lateral movement in work but limits
sway when raised.
30.11.37 Patent No. 510352 Major transmission improvements are acheived by
incorporating a constant running layshaft in the gearbox,
thus allowing the PTO and hydraulic pump to be driven
whenever the clutch is engaged whether in gear or not,
plus pump driven before or after dog clutch plus engine
drive PTO plus restatement of PTO shaft position as per
Patent No. 421983 rearwards within the three point
08.07.39 Patent No. 541220 Adjustable row crop front axle that allows the
track to be varied from 48 inches to 76 inches without
altering the front wheel alignment.