Parkgate standard or universal plough carriage
Forestry Commission copyright image of Forest Research photographs courtesy of Glenn Brearley, Roslin. CN114
A series of photographs taken at Parkgate Engineering Works owned by the Murray family who manufactured almost all the forestry ploughs from the 1950s through to the 1980s. This photograph taken by Donald Thomson in 1976 shows the front end of a Parkgate plough carriage with single furrow tine head attached. The lower and upper cross bars are the fittings for mounting two side disc coulters. The coulters and arms are not required in this set up and are not fitted but the centre coulter disc is which has a separate mounting system.
Note the hitching assembly with ‘muscle hitch’ attached to a heavy rod which is free to rotate within the drawbar. Inside the drawbar a steel collar is fitted onto the rod by a shear pin which passes through the sides of the collar and the middle of the heavy rod. In theory the shear pin was supposed to break if the plough hit a massive rock and reduce potential damage to the tractor rear end. In practice the author has seen very hard track bolts being used instead of shear pins which would certainly not break.
The attached PDF shows a more angled view of the same plough.
Groups: Tractors Ploughs and Drainage Machines