Editing Automatic lubricator (section)

==Friedmann/Nathan mechanical lubricator==
[[File:Nathan mechanical lubricator.JPG|thumb|Nathan mechanical lubricator fitted to South Maitland Railway ten class loco No.18 in preservation.]]The Friedmann system of mechanical lubricators included the DV & FSA type lubricators. This style of mechanical lubricator was designed & produced by Alex Friedmann KG of Austria. The DV type were then made under licence by in the US by the [[Nathan Manufacturing, Inc.|Nathan Manufacturing Co.]] & the type DV & FSA types in the UK by [[Davies & Metcalfe|Davies & Metcalfe Ltd.]]<ref name=Locolub />

Both types of lubricator are of the 'valveless' type, having no ball valves, springs or oil seals used in the operation of the pump units.<ref name=Locolub />

The DV range was available in range of sizes with capacities ranging from 8 to 36 pints, and the number of feeds from 1 to 26. Each of the lubricators consist of a reservoir, a ratchet assembly, a sliding shaft assembly, and the pump units. A screwed oil filler cap is fitted to the lockable hinged lid of the reservoir and a sight glass for indicating the oil level is fitted to the front face of the reservoir. The pumps of the DV type lubricator are operated by a sliding shaft assembly, unlike the Silverton or Wakefield lubricators which are operated by a rotating camshaft.<ref name=Locolub />

The FSA type lubricator differs by each pump having two separate pistons to control the pumping & distribution of oil. The pistons are driven by cams on the driving shaft. The driving shaft is driven via a means of a roller ratchet assembly which converts the reciprocating motion of the operating linkage to rotary motion.<ref name=Locolub />