A New Look at the Morphing Handcycle - Space Frame for Rigidity and No Gas Springs



Alan Ball sent along this concept that is based on our recent design meeting at John Baron's shop. This design separates two morphing arms to make the rear frame more 3D, instead of the earlier designs that essentially have the frame all in one vertical plane. The idea is to get better torsional rigidity and reduce weight. This design is based on using an NEMSHPEC gravity reduction system. (NEMSHPEC stands for Nylon Encased Multi-Strand High-Performance Elastic Cord ... or to most consumers "bungee" cord.) Instead of the gas springs of our earlier designs, this vehicle will actually use a multistrand shock cord to provide the morphing lift. We've tested it, and it works great. Its also much easier to adjust than a gas spring, and it will be lighter and less expensive. I also belive it will be more reliable. At New England Handcycles, we used shock cord for seat components, and for the centering spring. The cords are waterproof, tough, and seemed not to care about sun exposure, even over long periods of time. (years)

The cords are not shown in this early mock up.


Here is the e-Drawings file for the SolidWorks model:  You'll need the free e-Drawings Viewer (for Mac or PC)

How Smart Can a Mechanical System Be? Pretty Smart. Variable Rider Weight and Automatic Seat Adjust.

John Baron sent along this e-Drawings file of the test rig showing an adjustable mechanism to compensate for a variety of rider weights. On Morph II, we calibrated the shocks to work for Rory's weight. This worked very well, but doesn't work well for showing other riders. And its not practical for production.

So, one of the goals of the new morph is that it handle a range of rider weights with a simple adjustment. That's what John is testing here.

While Morph II had the frame as a single member, and had two gas shocks, the new design puts two frame members on the outside and a single shock in the middle.

Here's a bunch more photos.


By the way, the gold-colored mechanism is the automatic seat adjuster. As you morph up, it tilts the seat back by droppiing the rear of the seat. This corrects for the forward tilt that morphing up causes.

Here is the e-Drawings file for the SolidWorks model:  You'll need the free e-Drawings Viewer (for Mac or PC)

Designs for a Test Rig to Determine if a Morph Has the "Magic"

When the Morph is working right, it is truly magic. You float on the gas springs, and with virtually no effort, you can make yourself float up to talk to people, and then glide down to high-speed riding position. Morph II, our 60-lb steel prototype had the magic. But Morph III, which had the benefit of weighing in at only 40 pounds, lacked the magic. Why? Well, there are lots of reasons that we know, and maybe some we don't know. Morph III used locking gas springs, and they didn't have the same amount of force. We didn't get as much float. But the mechanism was different also.

So we went back to the Morph II design, and carried that forward into the MorphOut design. And we decided to make a flexible tester so we can try out designs in the morphing frame easily and see how they work when we sit on them.

This is the first version of a text rig to work out geometry for the MorphOut design. (We call it MorphOut as in getting out to users. Goal is to build five bikes and put them in people's hands soon!)

Here is the e-Drawings file for the SolidWorks model:  You'll need the free e-Drawings Viewer (for Mac or PC)


This is the CAD for an improved version of the test rig. This rig includes the ability to overlap the morphing arms, which we believe will be crucial for the eventual finished design. This added complexity to the test rig, but we thought it would be worth it to have a more complete view of how the design will work.

Here is the e-Drawings file for the SolidWorks model:  You'll need the free e-Drawings Viewer (for Mac or PC)


Below are progress photos from John Baron as of July 19th. The Telestrut tubing will allow us to bolt on anything we need as we proceed with our tests.

A Self-Adjusting Seat Mechanism for the Morphing Handcycle - Refining the Design (including a 3D Model)

This is an improved design from Alan Ball that uses the morphing struts to correct for seat tilt as you morph up and down.

Close-up of the seat adjustment mechansim showing the base supports for a slung seat design. The link arm shown in red causes the seat to adjust as the morphing happens.

The next step is to build a test rig to see how all of these designs work in real life before committing them to a finished design.

Here is the e-Drawings file for the SolidWorks model:  You'll need the free e-Drawings Viewer (for Mac or PC)

A Morphing Seat For The Morphing Handcycle - How to Correct Seat Position When You've Tilted the Frame by 20 Degrees

Alan sent these screen images along with a cool shadow border, so our post gets a slightly different look.

Shown above in green is the proposed morphing seat. Actually, there is the boxy (just for layout...not the real design) seat sub-frame. The end of the morph arm, along with the little tab that moves (how?) adjusts the seat angle to be correct in both low rider and high rider positions.

Oblique view.

Side view in high rider. The 74 inch rider isn't there.

Mid morph. The seat morphing mechanism is beginning to tilt the seat backwards.

Now the seat is tilting back more to correct for the morphing down, and to move the rider to the correct low-rider tilted-back position.

All the way down, in low-rider mode.

Issues to think about: 
1. How do we support the seat back? Needs to be very rigid as you power the pedals. Looks like it would be hard to put a strut between the morphng frame and the seat back, because dimensions are changing
2. Need a foot rest that lets the rider rest their feet in both low-rider and high rider positions.

Here is the e-Drawings file for the SolidWorks model:  You'll need the free e-Drawings Viewer (for Mac or PC)

The best way to visualize the design is to use this 3D viewer and change the configuration pull down to move the bike through its morphing range.




A Self-Adjusting Seat: Alan Ball Presents Two Designs for the Next Morphing Handcycle

Rory, Alan and I had an online design review session today. The latest design from Alan Ball looks at two ways to make the seat self adjusting when you morph. This version puts a hinge below the seat, at the same joint as the front morphing joint. There is a knuckle attached to the seat back that forces the seat forward as you morph down.

Bobby Hall seat positions shown in blue. Note that the Morph in low rider is a longer vehicle than the Bobby Hall. And that the rider sits further forward. Our seat height is about the same.

Now in high rider mode. Notice that the knuckle behind the seat is shorter. This tilted the seat back in high rider.

This is a different approach. A subframe is hinged just below the front of the seat. A tab pushes up the rear of the seat as you morph down. The seat tilts up at 11.5 degrees, which is what you want.

Version 2 showing the seat inn high rider mode. The mechanism has lowered the rear of the seat, and reduced the tilt. The grey lines show what the tilt would be without the mechanism. That tilt would be uncomfortable at best.

We are 2.87 degrees tilted forward. This seems to work well in high rider mode.

Without a seat tilt correction, the tilt is almost 11 degrees forward, which is not acceptable.

Click on the two versions of the model below to see it in 3D. You'll need the free e-Drawings Viewer (for Mac or PC)


Next Morph - 3D Model showing 5'2" and 6'2" Riders

We're just starting to look at different size riders for the Morph Out design. The 3D model below shows two rider sizes, 5'2" and 6'2", in low and high rider positions. Notice, for example, the position of the feet relative to the front wheel, and of the hands relative to the pedals. The bike is set for the larger rider.

The Solidworks e-Drawings file lets you see this vehicle in 3D, and also choose the configuration you wish to view (lower left of display). Get the free e-Drawings viewer here, and try it out!


Our Next Morph - "Morph Out" 'Cause We're Going to Build 5 And Get 'Em Out for Real Testing

This sequence shows the Morph Out geometry taken a step further into 3D. This is a just a proof of concept frame, but it uses the earlier "twin flanking members" to allow the rear morphing elements to overlap the main tube when the bike morphs down. This gives us extra room to put the seat sub-frame and still maintain a low riding position

The Solidworks e-Drawings file lets you see this vehicle in 3D, and also choose the configuration you wish to view (lower left of display). Get the free e-Drawings viewer here, and try it out!