When we think of safety on the ski slopes, it is not usually tractors or bright, warm summer days that come to mind. Yet, that is the topic of this custom machine design story and Engineering Case Study.
A tracked tractor is great for working on ski slopes in the summer, clearing the mountain in preparation for winter. With tracks, it can climb steeper slopes than it can safely stay upright on. Going up is useful. Tumbling down the mountain is obviously not.
We laugh, but the concern is not a theory. Another tractor took that tumble, so Synthesis was given an unusual engineering problem: Create a way to secure the tractor on the steep slopes, while still allowing it to do its job.
With no obvious off-the-shelf answer, we got creative, and that is where the engineering gets interesting.
The Engineering Challenge
The problem was not the tractor. These chippers, as they are often called, have the ability to drive anywhere. In the one case, a tractor went up a slope that was too steep, then tumbled back down.
Fortunately, the tractor is completely remote control. There is not a "driver's seat" or even a place to get into or onto it. That makes it nice from a safety perspective so workers do not have to be "on" or "in" the tractor.
To define the engineering problem, we start with a bunch of questions:
- How do you make a tractor stick to a mountainside?
- What is too steep for the tractor, and how steep does it need to go?
- How do you allow workers full access to it, yet constrain it from ever tumbling?
- How fast does it drive? Can we create a tether that will keep up?
- If the tractor is remote control, should the functions we add also be remote control?
- And, so many more.
In all our Specialty Tool / Equipment / Machine Design, questions come first. We seek to learn from our customer, to really understand the goals, limits, needs, safety, and more. We frame the engineering challenge, then we can work on solutions.
Constraints Shape The Solution
With this tractor, both function and safety are the drivers. So, we sought a solution that works with the existing tractor, preserves access around it, operates remotely, and functions on some seriously steep terrain.
Note that some of those constraints conflict. One that stands out is the need for access around the tractor. Workers must gather the cut branches and small logs, then put them in the front hopper. That means the front area must be clear of things that can hinder worker access.
Using a winch as a tether is a great idea, but as you can see from the photos (below), there is not a practical place in the front. A winch line in front would also encumber the area for access.
Operating angle is another interesting constraint. Normally, the chipper operation limit is a 30° incline, but sometimes they may want it to work on slopes up to a 45°. That too makes an interesting dilemma.
All of these requirements and constraints came into the formation of a custom machine design to solve the problem.
From Machine Design Concepts Through Build And Testing
After asking a lot of questions, and thinking through the many possible options, solutions emerged. Concepts solidified, and the project began to take form.
Our customer gave approval of the concepts – for both function and safety – then we did the CAD design. It is an iterative process of design, design review, then adjusting and continuing.
Next, we ordered parts, fabricated all the little things, and built this special safety add-on. It is one of a kind – like most of the things we do at Synthesis. Finally, we went to the site and installed it on the tractor, and tested it on the ski slopes.
This is the essence of a custom machine – in this case, adding custom safety equipment onto an existing tractor. Of course, it is a great project, but it also showcases in this engineering case study, the processes at Synthesis to achieve customer goals.
The Custom Safety System
The images on this page show the final machine in action, but they do not give justice in showing the steep slopes.
To address the many issues, this tractor was rigged with a custom machine addition that includes a winch system to secure it to the mountain while operating on steep slopes.
The winches are at the rear, mounted effectively on the back bumper. Guides manage the cable so it feeds finally from the front at whatever angle is needed. This makes the tractor stable. The extra guides also make the cables feed onto the winches in a very uniform fashion - even when they are used at a significant angle.
In the photos, you can see the gray attachments at the back, and the cable system in action. Two large, wirelessly controlled winches are in the box, one for each side, along with 3 large batteries. That keeps the added safety system remote-controlled, just like the tractor. The engine alternator recharges the system, while the batteries supply the transient high current needs - especially when operating both winches at once.
It is important to note, that this is a chipper, so by definition, it operates in areas where there are trees. There is no point in driving this tractor above the trees, where things can get really steep, because there is nothing there to chip. The anchor points are large trees with saver straps. The tractor does the climbing, the winches only keep it in place. With this, it can now operate on very steep ski runs without the risk of tumbling back to the bottom. A big improvement for safety on the steep summer slopes.
The specialty tool (machine) added to the tractor was both designed and built at Synthesis. A rewarding project to conceptualize, design, build, install, then test this custom machine.
Design For The Steepest Slopes
The wedge-shaped pieces sticking up, also attached to the rear. These are ramps to roll the tractor back onto, so it can chip, even when on a very steep slope. Normally, the chipper operation limit is a 30° incline, but with these ramps, the tractor can now function on a 45° slope. Yes, that is steep, and you can see the need for machine design for safety.
The blue straps hold the ramps to the chassis so they are easy to access, remove, and put back. By design, these ramps are not remote control. The cost to do that was beyond the desired scope of the machine design project. The ramps are manually set on the ground, then the machine backs up, onto them. This action effectively reduces the angle of incline for the tractor, even as it is there on the steep mountain slope.
These pictures show custom machine design work that comes from engineering experience. There are so many aspects of the design we have not explained. The machine design includes one-off parts (effectively prototype parts) designed specifically for this project. Of course, we purchase what we can for cost and reliability reasons, yet some components are created by CNC machining, others are laser cut, and still others are a combination for a great fabricated end result.
Every Custom Machine Is Unique
More than a good story, this engineering project demonstrates some of the things we do at Synthesis. This tractor is certainly an interesting example, but the engineering process is familiar. Understand the problem, define the requirements and constraints, explore possible solutions, then design, build, and test what is needed.
Custom machines at Synthesis come in many forms. Some are small specialty tools. Others are large, complex machines. Some become prototypes for production, while others, like this one, are built to solve one very specific problem. Each is unique, but the challenge is often the same: There is no off-the-shelf solution to do this job.
We are always happy to be part of a custom machine design that makes the world better in some small way.
This tractor is a medium-size custom machine design for us. We did not build the tractor, only modified it for the new additions. For an example of something much more complex, check out the SIM Demonstration Video which is much larger in size, and totally different in purpose.
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