Model: 4-Person, 2-Pitch (750-pound capacity)
Track: 140', ~80' at 24° at the top and the rest at 46°
These cottage owners needed a 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 be seen from the top station.
After years of building only single-pitch lifts that could not work on these sites we developed a two-pitch lift. The inspiration for our design came from the 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 reverse the wheels, use a cantilevered geometry with the car base attached to the lower end of the dolly, and add a "pipe" track to the outside of the standard track to keep the car floor level.
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 lift design solves a challenging terrain problem with an elegantly simple engineering solution and the prototype, Lift 41, worked exactly as expected. We've since built 6 more 2-pitch lifts with virtually no design changes.