October 30, 2012
This is a follow up article to Ruben's observations on using a piece of heavy equipment to move an insulated shipping container, fondly referred to as "Icy", from the upper garden down to closer to the dining hall.
A general principle of applied engineering is that scale matters, and that an order-of-magnitude change of scale usually warrants using a different tool set. The task of moving Icy into its final position called for a different set of tools and techniques, small steel if you will, instead of the mamoth machine that just dragged it downhill from the upper garden.
This article will describe some of the tools and techniques used in moving a five ton steel box by hand.
The trackhoe had left Icy in a north-south orientation with the door end facing north, so the first task was to pull the front end around to where Icy was pointing in a northwestern direction. Once that was accomplished, the chains and pivots were repositioned so that the container could continue to be rotated counter-clockwise until it was facing west.
looking downhill (south) towards Icy as it starts the move west
This phase of the work involved using a lot of chain so that Icy would rotate in the desired direction. In that this work was being done on a slope, it was important to use chains to keep the front end from sliding down hill as we pulled the back end up hill.
using a large stump as a pull point
using 60' of chains and the 5-ton come-along
close up of the 5-ton come-along
Another key component is a 20-ton hydraulic "bottle jack" to lift one end of the container so that slides could be put into place. A 40' container that's laying on the ground would require a lot of force to move side-ways. We get around that through the use of steel slides, and the bottle jack is the way that we lift the container high enough to position the slides.
a 20-ton bottle jack
Each movement cycle involves positioning slides and jacks so that the come-along will be able to move the container a few feet closer to the goal. A cycle ends when the container gets close to the end of the slide, which then has to be repositioned.
getting too close to the end
the slide repositioned
lubing up the slide with motor oil
Icy sliding uphill on the slide
By using the bottle jack to lift one end, the container slides easier. As it moves, the jack tilts over on its side, and after about six inches of movement, the jack falls over allowing Icy to come to rest with its weight fully on the slide.
The bottle jack is then reset, the container raised, and the process repeated.
Ruben working the 5-ton come-along
Since a chain hooks to itself in discrete steps (link by link), there will necessarily be some slack. That slack is taken up using a chain binder. This is especially important when a chain will be working under tension since it will need some slack in order to be removed when the work is done.
a chain binder in the open position
in the half-way position
using a "cheater" bar to apply pressure to the handle
the chain binder in the closed position; note the slack in the chain below the binder, slack that will enable the chain to be unhooked when the work is done
Another key tool is the high-lift farm jack, here painted yellow to make it easier to find when the fall leaves quickly hide such things. The jack has a toggle that determines whether it goes up or down; it's the curved piece in the upper center of the jack mechanism. When the toggle is in the up position, each stroke of the jack handle causes the jack to go up one notch. When it's in the down position, each storke causes the jack to go down a notch.
the farm jack with the toggle in the "up" position
the farm jack with the toggle in the "down" position
It took some seven hours of work spread over a week's time, but eventually Icy was moved forty feet north and some forty feet to the west, all using some hand tools and a lot of persistence.
Icy ready to head west to its final destination