SOME EARLY DIGGERSHi,
I think I posted on here somewhere that the first hydraulic backhoe I used was a MF 203 with a 220 digger on the back, and that was the first I learned to drive properly.
I did however, before that, get to do some trenching with an "Allen Tractor Operated Shovel," (ATOS), circa 1958/9. It was owned by a local farmer and I used it behind my old IH TD6 crawler.
The ATOS was driven from the tractor PTO and was quite useful, a big improvement on the alternative pick and shovel anyway.
I recently found an article from the launch of this machine in 1952. It had no bucket crowd, the bucket was fixed in one of three positions as can be seen from the pic. below. There were no stabiliser legs either , there was a sort of sprag arrangement like a winch anchor which was designed to pull into the ground when you started digging. If I remember rightly it slewed about 45 deg. to either side.
According to the write up I found it would dig to 8ft. 6in. deep and load over height was 12ft. 9in.
The hydraulic system used three separate pumps one for each of the movements so that full power was available to each ram when using two or three services together. Control was by three levers.
Like most hydraulics of that era pressures were low 1,000 Pounds for hoist and arm and 750 pounds for slew.
The Whitlock Dinkum Digger of the same year had no bucket crowd and similar stabilisers to the Allen too. (see below)
This pic of a Dinkum on a Platypus PD2 dozer shows that they had sorted a bucket crowd ram out by 1954.