|1939 Ford Dump|
I found this 1939 Ford Truck for sale at a charity auction (and resisted buying it). I am told that this is the last year that Ford trucks featured a place for the crank to start them, and also was the first year that this model was equipped with hydraulic brakes. Before the advent of hydraulic brakes, vehicles had mechanical brakes. They consisted of levers and cables connecting the foot pedal to the brakes. They were most difficult to keep adjusted properly. Hydraulic brakes equalize the pressure among themselves, but with mechanicals if one was a little tighter it did all the work.
Now days with the advent of Commercial Driver's license Issues for farmers, many are now using flat bed trailers behind a hefty pickup to haul whatever around, but in days past, it was the norm for every farmer to have a single axle flat bed truck around. It would be a flat bed and ideally it would have a hoist under it so you could dump the load off. The Hoists were usually of the scissors variety which are really sort of spooky but easy to install.
Modern dump trucks now usually have direct lift cylinders implying that they are configured to lift the bed without linkages. Sometimes they will be a compound extending cylinder located vertically right behind the cab, and other times they will be a pair of cylinders with the butts low and forward just outside the frame with the rods pointed up and to the rear. This design uses cheaper cylinders but have the leverage against them at the beginning of the lift which is just the time they need the most strength.
The old scissors hoist was generally a large single cylinder mounted horizontally usually in a subframe well to the rear of the bed. IT was often an 8" cylinder or so, infrequently had the control valve integrated with it. Since it was a single acting cylinder, the off side off the cylinder was used as the oil tank, so when you extended the cylinder you were merely pumping oil from one side of the piston to the other. The cylinder was connected to an A shaped toggle. Imagine one leg of the 'A' on a pivot anchored to the truck frame with the cylinder pushing on the top of the 'A'. Now the front legs of the 'A' had connecting bars extending upwards to the bottom of the bed. Now, as the cylinder extended it 'tipped the 'A' over on its side shoving the bed straight up. Of course the bed was fastened with hinges on the back so the bed hinged up. This compounding linkage allowed about a 12 inch hydraulic stroke to tilt a bed way up in the air. The hazard of the things was that with the compound linkage, the bed could come down at an amazing speed, and if the linkage or the rear hinge broke the bed could just fall down. I had this experience once while dumping a load of gravel. I was trying to spread rock going down hill and it didn't slide off right so I let the truck roll ahead and then stopped it. The rear hinge gave way, and the bed with the load of rock flopped over the hoist and hit the truck so violently that it smashed the truck frame about half way to the ground.
Anyhow back to the point, a truck of this type was a farmers dream of a replacement for a team and a wagon. With the right kind of a rack on the bed you could haul what ever your produced, cows, hogs, sheep, hay, grain, etc. to market and return with what ever farm supplies you might need. These days, however, farmers are not taking their produce to a market as close as it was when they did it by wagon. Markets are further and further away, and the tendency has been for every larger trucks to do the main hauling. The availability of sturdy Pickups and trailers has taken care of the smaller stuff, making the one size fits all farm truck less common than it used to be.