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 ensure depth.
• 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 original.
• 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 transmission torque.
• 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 Patent.
• 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 obstruction.
• 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 linkage.
• 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.

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