Model: 4-Person, 2-Pitch (750-pound capacity)
Track: 140', ~80' at 24° at the top and the rest at 46°
Area: Lake of Bays
Year: 2011
These cottage owners needed the lift to access their boathouse, but a single pitch lift would not work, the top part of the slope was flatter than the bottom part and the lower station could not be seen from the top station.
After years of building only 1-pitch lifts that could not work on these sites we developed a 2-pitch lift. The inspiration for our design came from the simple and brilliant Big Chute Railway which connects the Severn River to Georgian Bay at Port Severn. There, the lower wheels ride on one set of tracks and the upper wheels ride on another. Simple geometry required that we use a cantilevered geometry where the car base is attached to the lower end of the dolly with a massive hinge ,and triangular “back-riggers” added to a standard 4-person car. These back-riggers have U rollers that roll under the "pipe" track, a second track welded to the outside of a slightly narrower version of our standard track. The pipe track has the same curvature as the main track but it’s displaced uphill. The back-rigger rollers and the pipe track interact to keep the car level at all times.
The car looks almost the same as a standard car on the upper pitch. Chain rather than hard welded angle iron stay hold the car level here. The upper station platform is cantilevered out from the path running behind the house. Because the platform is single purpose and not far off the ground on the track side, the owner opted to not add a gate.
Heavy duty "V" rollers are mounted on the crossers to curve the suspension cable smoothly over the curve in the track. The cable on the left side turns the governor that trips the over-speed brakes if the car goes faster than 0.5 m/sec or ~100 fps.
The car tucks in at the back of the added section of the dock, out of the way and right there.
Scott MacDougall made the first run with a person on board. We'd run it over the curve several times empty and there were no problems, no concerns, and no surprises. The lift is obviously still under construction at this point.
Here the upper section of track runs from the cottage station to the top of a cliff where it is connected to a curved section (which is an arc of a circle). This curved section then transitions smoothly to a second, steeper section that runs to the lower dock station. Installing the 2-pitch track required developing some new techniques: when we set the first, uppermost section of track it has to be positioned so that the lower station will be where it needs to be even though we can't see the lower station.
The mechanism that keeps the car level throughout its ride (including the 22-degree change in pitch) is simple and robust. The video shows the car going over the curve.
We did all the engineering and construction of the curved track section (aside from the actual bending of the 3 sections of angle iron and the one section of heavy wall pipe and some machining), and the car/dolly/track system in-house. There are no added motors, pumps, batteries, switches, hydraulic cylinders, or black boxes to complicate things or to fail.
This 2-pitch lift design solves a challenging terrain problem with an elegantly simple engineering solution and worked exactly as expected. We've since built many more 2-pitch lifts and even a 3-pitch lift, Lift 86, with only a few design changes.