The E-Car-Go, a Compact, Leaning Cargo Trike

 

I have built five versions of a commuter trike prototype. To reconcile a having a car-height posture with a width that is narrow enough for bike paths, they have all been learnable. To be controlable on slippery surfaces they all had two-wheel drive. With a hub motor in front, the trikes are all-wheel-drive. All these vehicle have the designator EcoVia.

 EV1 and EV4 had tadpole layouts with rear steering. Both suffered from instabilities. EV2 and EV3 were delta trikes. EV3 worked well enough that I use it to run errands in my neighborhood. EV3 used much of the hardware from EV2, which resulted in the design being overly complex.

When EV4 failed last fall, I decided  to fix the obvious defects in EV3 and came up with EV5. Some of the hardware from EV3 and EV4 were reused in version five. Because of its large cargo capacity, EV5 has been renamed "E-Car-Go"

EV3 is shown below.

The EV3's rear wheels are mounted on beams that pivot to facilitate leaning. The pedals drive a jackshaft with a cassette in the middle and freewheels on the ends.  Chains connect the freewheels to fixed cogs on the wheel axles on the other end of the wheel beams. The freewheels act as a positraction differential. The EV3 is  not free-leaning. A lean lever allows for controlled leaning and there is a lean lock that can bias the lean lever force from free to being locked up. Steering is the under-seat type and leaning is controlled by a lever on the left side of the trike. Pulling back on the lever leans left and pushing on the lever leans right. Lean control is very intuitive. Below is the lean-lock that was repurposed from the EV3

Below is the E-Car-Go. The overall length if 80in., the width is 32" and the seat height is 20". 

Numerous improvements have been made in the ECG.

1. To prevent wheel slip form the front motor wheel, a wider tire of 2.125" was substituted for the 1.35" wide rear tires

2. The intermediate bottom bracket, crankset, chainrings and chain where eliminated by connecting the cranks directly to the jackshaft with one chain and an idler.

3. A 1x12 drive was used having a gear range of 26 to 94gear inches.

4. A stiffer scissors joint with .625" bronze bushings was used to support the seat beam.

5. A bicycle shock absorber was substituted for the coil spring of the EV3. Changing the internal pressure of the shock allows for spring-rate adjustment to match rider and cargo weight.

6. The lean angle limit was increased from 17deg  to 20 deg.

The lean control lever is shown below.

Leaning left.

Leaning right

7. Return springs were added to the lean lever

8. The brake modulator linkage, which equalizes rear-wheel braking to keep the trike moving straight when stopping has been improved. It is now symmetric insuring that the cable lengths for each brake are equal and have the same friction.

9. The construction of the wheel-beam assemblies has been simplified.

10. A second transport crate was added below the first crate. The crates have a volume of 1800cu.in.

Below is a sketch of an enclosed version of the ECG with the wheelbase extended to enlarge the cargo carrying capacity.

  

Hephaestus

8/7/2024

A Full-body Exercise Recumbent: The Omnidyne 3P

 

My readers will recall that I previous did a post on my experience adding arm power to my Avatar recumbent.

http://lefthandedcyclist.blogspot.com/2012/03/arm-power-and-avatar.html

Now to recap, the Avatar approach used a bolt-on rocking-handlebar and a freewheel added to the left side of the crank axle. Pulling on the handlebars pulled on a chain passing under the crank freewheel moving the pedals forward. A spring attached to the other end of the chain moved the handlebars backward when the pulling force was removed. The linkage connecting the handlebars to the steering was designed to decouple the rocking from the steering.

This arm-power-mechanism worked fine for riding on the flats but was not efficient for climbing hills. Since the handlebars moved at about half the speed of the pedals, the force from pulling on the handle bars was applied every other pedal stroke. On hills this resulted in there being more torque than needed for half the cycle and less for the other half.

The solution was to be able to push the handlebars as well as pulling them. The arms would contribute torque on each  pedal stroke.

 I would need two freewheels to accomplish this and couldn't fit them both on the left side of a single crankset. This meant I would have to add a second bottom bracket with three chainrings on the right side and two freewheels on the left. On the right side, innermost chainring would be connected to a single chainring driven by the pedal crankset.  This would be mounted in front of the second bottom bracket. Back to the right side, the middle and outer chainrings would drive the rear cassette in the conventional manner. 

The presence of a second bottom bracket required that I build a new frame to support it. And I realized that if I mounted the pedals directly over the 16" front wheel, I could shorten the wheelbase of the new bike by 12" when compared to the Avatar. The steering decoupled handlebars would be transferred from the Avatar but modified to facilitate the dual drive.

The freewheels used were the same size as used on the Avatar. Since the force produced by the handlebars with the Avatar was well matched to the pedaling, the goal was to keep things the same for the Omnidyne. The rocking handle bar has two beams attached to it, one on either side of the freewheel  pair. Pulling back engages the outer freewheel while the other freewheel ratchets. Pushing forward engages the inner freewheel while the outer freewheel ratchets. The beams started as the same length used on the Avatar, but since a greater force could be produced pushing compared to pulling, the pushing beam was lengthened. The distal end of each chain is attached to a spring to keep them taught.

As of late I haven't painted the parts and the Omnidyne has not been ridden outside. I like the new motion so much I have been using it as an exercise bike for the last year. I am confident that the push, pull, pedal motion, (3P), will drastically improve the bike's hill climbing.

Hephaestus