Introduction: Cable Car
My grandma has trouble walking these days and I was going to build her a ramp. After examining code requirements, etc, I realized that a full sized ramp would take up a lot of space and be very expensive. I had to figure something out that would help grandma and my wallet at the same time.
So, after mulling about a few configurations and set-ups for a feasible ramp, I had a brain storm. Why not build an elevator? Further exploration of that idea exposed a few safety issues that I simply could not resolve to any degree of comfort or assurance of grandma's safety.
But, the seed was planted. I could not get the idea of a powered lift for grandma out of my mind.
This is where those musings led.
Step 1: Making the Plans
The first thing I had to do was determine where to put it and the needs of grandma to design it's function. First, it had to eliminate any steps between the house and the garage where the car is parked. Second it had to fit her small 35" motorized chair. And finally, it had to support her weight combined with the weight of her chair, or a cummulative rough 300 pounds.
Previously, there had been a short ramp in place for her to walk down. But, now the slope was too steep for her to walk down and her cart could not manage that degree of slope safely. But it's location was relative to the spot where a different ramp would work well.
Off her back porch I had built a 10' x 13' deck some 3 years ago.I decided to build the cable car adjacent and parallel to that deck so that she could simply roll out off the porch, across a few feet of deck and onto the car platform. I decided to build the platform to rise level with the deck at the top of it's rise and settle flush with ground level at the bottom.
So, I began by digging out the area next to the deck. Then I marked the locations for a few footers to build posts up to hold the rails.
Step 2: Placing the Footers
The idea was to roll a platform down two rails. So, I had to install eight footers to a depth of only 12 to 18 inches on which I would install short posts on which the rails would rest.
Step 3: Laying the Base
As you can see, the base drops about 18" below bround level. This will allow the platform to rest flush with the gound level at the bottom of it's run. But, I couldn't just leave it as a muddy pit below.
So, I layed in a layer of wire mesh on the ground surface, then pured in a 2" layer of concrete as a base. I installed a drain at the far end to keep it from filling with water. Then I cased it in with brick.
The drain was extended out from the base about two feet to link up with a french drain which I am now digging across the back yard to keep the rain out of the basement.
Step 4: Posts and Rails
The idea was that the platform will roll up and down a pair of parralel rails. So, once the concrete set, I cut posts from PT 4"x4"'s and using lag screws I attached the rails at about a 20 degree angle. The rails are cut from PT 2"x6" and run a bit over eight feet long.
I screwed the rails in line with the inside line of the posts so that there is a 2" over hang on the outside permitting the lower rear wheels two ride past them on the bottom of the rail. These are shown in the next step.
Step 5: The Platform
Now that the base and rails were installed, it was time to begin construction of the platform.
Essentially, it is a simple 40"x40" platform angled and set on wheels. I used PT 2"x10" to form two cantilevers on the outside of each rail and then tied them together with PT 2"x4"s and used deck hardware for added strength.
The front wheels I salvaged from my son's now defunct Hinda Minimoto motorcycle. They are 10" wheels with inclusive bearings. These became very important from a safety standpoint which I will explain in my next step.
On the rear of the platform, I used two sets of smaller wheels on each cantilever. Like a roller coaster, I positioned a small wheel on the top and the bottom of each rail to grab the rail and keep it from flipping forward.
Step 6: Safety!
Now the whole purpose of this project is to make grandma's life easier while at the same time feeding my need for eccentric efforts.
The idea of a little old lady careening uncontrolled down an eight foot ramp because the cable snapped was simply a stopper to this project until I could figure out a way to pre-empt such a disaster.
This is where those Minimoto wheels come into play. I thought they had been thrown away with the rest of the bike after I took out the electric motor last summer. While searching for something else, I found them , much to my suprise, stuck up on a shelf in the garage next to an old Ford 5-speed transmission from my old Escort.
On the rear wheel of the motorcycle was a drum brake! How absolutely incredibly lucky was that! The project could proceed.
I loaded the brake with a spring on one side which locked the brake. Then from the other side of the brake, I ran a cable to the main cable. So, if the main cable snaps, the spring will automatically retract and lock the brake
Step 7: Power
I bought an electric hoist motor with a 450 pound strength to use to operate the car. It's only 110 volt with a max draw of 20 amps.
From the basement, I ran a power line from a dedicated breaker and used water-proof conduit and junction boxes. this step was probably the easiest.
I mounted the motor below the rails inside the rear-most posts. Then I used 485 pound test pulleys to run the cables to the platform. All the hardware holding the motor, pulleys and cables is stainless. Nothing is too good for Grandma!
Step 8: Completeing the Platform
Once the motor was installed, I test-ran the whole works. The platform rolls smoothly up and down the rails, each run taking approximately 30 seconds, for a full one minute circuit.
I've tried to load a video of my test run, but can't quite figure out how. I've posted a question about that in the Help section and will include it in a re-edit once I've figured it out.
Finally, I laid on decking as a walking surface and installed a light-weight railing.
At the bottom of the run, I poured a concrete pad which matches up flush with the platform at the bottom of the run. Grandma can roll out onto the deck and right across on to the platform at the top. Then an easy decline down to ground level where she can roll right out onto the sidewalk and then to where ever she'd like to go from there.
The only issue I still haveto figure out is how to put the control on the platform itself. The control wire is only five feet and I need it to extend about nine feet to followthe platform. But at the same time it needs to neither drag on the ground nor be run over by the platform itself without being lifted overhead. If anyone has any thoughts an that matter, I'd be happy to hear them.
Thanks for reading everybody!