Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Monday, May 2, 2016

Powerful Machines Need Finesse

Last week I saw a set of land-clearing machines munch their way across a triangular vacant lot in less than a day. I'd heard about such equipment but had never had a chance to see them close up. 

Basically, the first machine (the feller-buncher) cuts down trees; a second machine, the skidder, drags the timber to a staging area; and a third machine, a tracked excavator with a grabber attachment, feeds the maw of a fourth machine, the horizontal grinder. The grinder shoots the chips into a semi-trailer. 

Later in the day, two more tracked machines went over the ground to prepare for parking-lot work: a stump-grinder and a mulcher.

The feller-buncher looks similar to a trackhoe, but at the end of its boom it has a hydraulic attachment with a really big circular saw and a gripper. The operator rotates and tilts the attachment to align with a trunk or branch, and pushes in the saw blade. Using the gripper above the saw, he can hold on to the newly-cut section to set it into a pile, or can push it over to land on the other side. 

Here's a view of the feller-buncher at work:

A newbie operator would be well-advised to watch a seasoned one at work, before taking the controls. A good operator learns more than how to handle the many levers; he or she needs to learn safety and economy of motion. Feller-bunchers can cost well over a quarter-million dollars and a careless operator can cause a lot of damage to the machine, nearby people, and structures. One challenge is that the feller-buncher is always working around stumps, which can damage the undercarriage or throw it off balance at a bad time.

While the machine is capable of taking down a big tree with a single saw-cut, instead this operator took down big and even medium-sized trees one bite at a time. This avoids overloading the feller-buncher and saves the skidder operator a lot of time in gathering up the felled timber. 

See this time-lapse of the feller-buncher, spanning less than an hour of equipment time: