Morphing Handcycle Gets Closer to a Build Version - Narrower Frame

Side view - low rider mode.  (The "front" designation from Solidworks isn't true...I avoided capturing it in the following screen images.

Had an online session today with Alan Ball, Rory McCarthy, and Bill Warner. The Morph is Rory's invention, Alan is providing industrial design, and Bill is providing project management and design input.

Side view - high rider mode.

Top view - low rider mode.

Front View - Low rider mode. Not how very low this vehicle goes.

Front View - High rider mode - and in high mode (like all our designs) the bike goes to a seating height above the rear wheels, which are 27"

Iso View - High rider mode. Note the twin tubes for the upper and lower link arms. This lets the purple frame nestle between them in the low mode.

Low Rider Iso. Seat is still in the works.

The red area shows the single gas shock in this design. It is compressed here, at a length of 9.7 inches.

High Rider Mode - Gas spring is at 14.1 inches. We are planning on a single gas spring in this design. Morph II had two gas springs.

Still some interference between the shock and the main tube. Will fix this.

Alan is working on the tube paths. The version we currently have, with 12" radius curve, puts the tube too close to the seat supports, and too close to the seat back. We working on this issue a bit today.

The blue tube should really go through the center of the grey seat support.

The orange circle represents the seat support. The purple tube needs to come back further and then rise at a steeper angle.

Can a 10" radius do it. No.

Can a 6" radius get the tube in the right position? No. And 6" is the very smallest radius that could be considered in a 2" tube. (and that's not a great idea.)

Here we remove the radius, but we still have interference.

Now we move the tube back further and angle up.

This is basically an angle-cut weld. (Not shown exactly that way.) High rider mode.

Angle-tube in low rider mode.

Still some interference of the top seat support. 

Alan is going to work some more on the frame design and resolving the interferences. Then our plan is to make a new wood model which we'll use to nail down the final frame design. Its much easier to discuss ideas when you have an actual model in your hands.

The Morphing Handcycle Gets a Simplified Tubular Frame - Getting Much Easier to Build

Alan Ball, Rory McCarthy, and Bill Warner got on the phone today to go over the latest design. Here it is, with a simplified tubular frame. Easy to build

Low rider mode. Not that seat back and many other parts are not shown in this simplified model.

High Rider side view

High Rider iso

Low rider side view. We added some color to make it clearer. Main tube looks like it wants a bend.

Low rider top view

Low rider front view

Low rider iso.

High rider iso with coloring.

High rider side view with coloring

High rider to view

High rider front view

Lets curve the main tube. Try 6" radius.

Curved tube at 6" radius.

Higher radius -- 10 "?

Higher radis - 12". This looks nice.

Iso with curved tube 12" radius.

Curved.

Curved.

Curved.

Curved.

We agreed that the function looks good, and now we just need to talk about some more asthetics.

Morph HC Online Sketch Session with Rory McCarthy and Alan Ball - We Start Curvy and Go Straight.

We started the session by looking at the issue of curved vs. straight tubes. Alan turned on the layer that shows where the main joints are.

Just in case you want some dimensions and angles.

Curvy Morph in upright mode. Bill expresses concerns about curved tubes. One concern is how it looks...not as angular as our earlier designs, and also the difficulty in fabrication. Discussion moves to what would a design with straight tubes look like. Alan made some screen captures and we did some overlay drawings.

Here we straighten some of the tubes.

Now the upper tube has once joint, rather than two.

Lower member also now has one joint.

Now we look at straightening the main tube. But it bangs into the seat, which can change angles.

Now the main straight tube is below the seat joints.

Adding the gusset tube to the head tube.

Another design for the main tube. One little weld, and then it hits the head tube in the middle.

How it looks in low rider mode.

Now exploring how to make the members look good in low rider. Want them to be parallel.

The upper, blue member now has an angle that causes the tube to be parallel to the green one on the bottom.

Same design in high rider mode.

We discussed that there are 6 places where we have a fork. (oh my!). Need to figure out something that is lightweight, low cost, and looks good, and then gets repeated six times.

The center upper drawing shows a very short fork at #6.

We agreed that Alan should take another pass at the frame design, and we'll get back on the phone to refine further. Note that the initial curvy frame that he designed was about 3 hours of work! We are getting very fast at being able to make new morph designs in very minimal time.

New Frame Design for the Morph: Back to a Single Tube. The Bike Look is Back, But We Kept all the Good Stuff.

Just received this concept model from Alan Ball. Rory, Bill and Alan will have an online design meeting tomorrow to discuss this new approach. We have moved back to a more "planar" and more bike-like frame with single tubes. One wheel is hidden to reveal the frame.

Here you can see the "fork" apprach to what we used to call "twin flanking members." These forks let the frame overlap, and allow the morphing to go lower, for good distance riding stability and cornering.

Low rider mode. Not sure about the curved sections. They could be hard to fabricate. But this is just a concept model.

Wheel and seat removed, and you can see how the fork allows the main tube to morph lower without interference.

Here's a look at the previous design, which spead the frame members out to the sides. Better for strength, but many more parts, more metal, and it loses the bike look. That's way we went to this design, that combines the single tube look with the forks that give us our flanking members.

Click here: http://www.edrawingsviewer.com/ to download the viewer for Mac or PC. You'll need it to see the files below: Note that this concept design doesn't show the handcranks or any of the front end.

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More on the Low-Cost Wooden Model That Moves: Designing a Morphing Handcycle By Seeing It In Action

Alan Ball sent along an e-Drawings file of the 3D Solidworks model that he used to cut out the wooden pieces to make the 1/8 scale model of the most recent design of the Morphing Handcycle.  An overview of the project is at www.movewithfreedom.org. This technique of using CNC-routed wood parts is very significant, because it lets us understand a design in "real life" at very low cost.

Note that our next design is going to take some of the concepts in this model, but will go back to a more planar frame, which will have more of a "bike" look. We may use this style of design on a future morphing wheelchair.

Click here: http://www.edrawingsviewer.com/ to download the viewer for Mac or PC. You'll need it to see the files below

Below is another output of the Powerpoint file that shows animations using the wooden model. The previous version used a PDF output, but I worry that the PDF takes a long time to load. Below are JPEGs from that same file. Just click through the images to see the frame animate.

A Wood Model Reveals: How to Understand the Self-Adjusting Seat on the Morphing Handcycle (choose full screen, and set view mode to "slide")

(Set viewer to "SLIDE" mode shown on lower left so animations will work)

This Powerpoint presentation and animation uses Alan Ball's clever and low-cost 1/8 scale wooden model to let us see how the seat bottom and seat back magically change angles to correct for tilt when the bike morphs up and down. Very cool, and it really works! (Note: this is a re-post using a PDF format from the the original Powerpoint)

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)

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.