Congrats with the competition win with Ze Chair.  I'll take your word for it that it was comfortable   With these competitions was the objective/requirement that all parts, except mechanical fasteners, to be wood?  Just thinking a bit of metal reinforcement/decoration would have been a solution...  But, the use of BB plywood would likely work also - that's what I used to address a chair joint failure for our daughter a year or so back.  Internet plans and all

In those days, and I believe it is still the rule that at least 75% of a design for the competition must be wood.  The competition was during the International Woodworking Fair, a huge bi-annual trade show.  I'm not sure they were too sticky about the rule as usually if a design was good looking no one got out tape measures and calculators to check,  And they never specified if the rule was about weight or volume or visibility of wood vs steel (or anything else) in the design.

Roughly 70% of the residential furniture market is wood.  Add a few more percentage for the wood frames in upholstered furniture.  As far as I know no one sponsors competitions for metal furniture designs.  No where close to the aesthetic variety possible in mass produced furniture made from wood.  

 

As for Ze-Chair, I think I have all the parts in a box in my garage,  That is unless I cut some of them up to make other things over the years since then. Having a CNC to play with I could easily cut a pocket in the part ends for a Baltic birch inset.   I could even cut a recess for a metal flange washer to sit in the Baltic birch if I felt metal was needed.  If I ever get around to that I'll invite you over to try out the chair. Might need new foam in the seat and back though. 

4D

Went to look.  No sign of the Ze-Chair parts where I though they might be.  Did find a few nice pieces of walnut that I can use for the walnut pedestal table legs. One looks like African walnut.  As dark as the walnut cylinders that had been the legs of a coffee table I made in the '79 or so. 

In the early days of the IWF Design Emphasis Competition colleges could bring any number of furniture pieces that they thought might do well. As furniture design courses were part of the curriculum at K-State and every students had to make at least 3 pieces while they were there, we always had a van full of students pulling a trailer full of furniture projects.  Students that made it to the competition had 5 minutes each to present their designs to the judges.   I had the Ze-Chair parts nicely packed in a box, and when my turn to presents I spent the first minute unpacking and assembling it, then invited each judge to have a sit.   

The last decade or so the competition has online submissions, limited to no more than 10 projects from any school.  They are pre-screened by the judges to bring the total number of projects to make the competition down to 100 or so.  No students allowed in the area when the judges do the judging.  The projects and the posters required to accompany them have to explain the features and sell the design.   

4D

For the seat, I'm borrowing what I did with my Fit Lounge Chair. Canvas wraps over a dowel trapped in the front seat frame stretcher, back around them to a 1" dowel at the back of the seat. Wrapped under it proceeds to a loop sew in it that has a 1/2" metal rod running through it. The ends of the metal rod sit in cam levers mounted to the inside face of the seat frame. The cam levers can stretch the canvas so it is drum tight.  With cushion atop occupants have good support but will never bottom out or feel a hard surface. 

The back canvas is next, and is simpler in concept. It wraps over the bottom rear leg stretcher, and will need a slot in it to account for the linear actuator.  Should have the back canvas pathway drawn up tomorrow.  Second and third photos here show the canvas as used in my lounge chair: https://4dfurniture.blogspot.com/2022/08/a-folding-lounge-chair-my-award-winning.html.

 

4D

I like that Fit chair 4D!

1 hour ago, Cal said:

I like that Fit chair 4D!

Thanks Cal. That chair has been through 3 recoverings of the cushions.  It was where I planted myself after getting home from work each day for 40 years.  I often hauled it to work to show the students the value of a soft seat vs a hard seat, and one way to compress furniture for compact shipping or simple carrying.  Folding/unfolding, for some reason, was a rare feature students chose to tackle. Two times in 40 years I had students who attempted to design and make a folding chair.   I suspect it was a feature that helped my projects win awards against static but beautiful work from other students from all corners of the country.  A 4th dimension property.   

4D

Canvas pathway to support the cushion back.  There will be two 2" wide straps, furniture grade with just a little elasticity, running from side to side across the back at lumbar height.  The canvas start on the front face of the upper chair back stretcher, and is held they with Velcro strips.  It wrap down and back over the top to cover where it started, then down in front of the elastic strap to a 1" dowel near the top of the rear legs. Around the dowel and down to the bottom stretcher where it wraps around to eventually stick to itself with more Velcro. 

I'm close to having all the details worked out. Unknown is if the linear actuator can move the chair through its range when I'm sitting in it.  Wheels need to be found and how they mount needs to be determined. I've got some 3" diameter poly scooter wheels I could use.  I'd rather use something 2.25" to 2.5" diameter max.  These will be bolted to the bottom inside of the rear legs. 

4D 

This is the chair will all the parts and canvas moved to the fully reclined position. In Aspire I had to do it in steps, starting with rear leg, then the attached link, then the back with arm, then the back's link.  The canvas for the back had to be adjusted to reconnect to the new angle between back and rear leg. 

 

Hopefully in real life the reclining action will be a smooth dynamic dance with all parts moving through their movements together. 

4D

Smallest wheels I could find with a bearings were 64mm suitcase wheels.   I only wanted the wheel to stick out 1/8" from the bottom edge from the rear leg, so letting go of centering the wheel I reasoned I could offset the mounting point of the 64mm wheel so only 1/8" of it was sticking out through the 33.42 degrees rotation of the leg as the chair reclined. 

I'm not concerned about the wheels screwing up the critical seat and back angle as I know on carpet with most of the occupant weight bearing down on the rear wheels they will compress into the carpet.   Any chair I design with mechanical parts is initially only a prototype.   If the seat/back angles or the links or arms don't work when I first try the assembled chair that info serves to focus on the changes needed for prototype 2.  While teaching furniture design we usually only had time in a semester for 2 tries/2 prototypes.  This was true for my Ze chair.  It was my second try.   A third version, made after using that chair for a year or two before it started to fail, would focus on finding solutions for the flaws discovered.  "3rd time is a charm" has basis in the truth of chair design.  It takes 3 tries to get as close as reason expects to a "perfect" chair. 

4D

I'll hazard a guess that with only 1/8" of wheel clearance, it's not shag carpet you'll be putting it on

37 minutes ago, Cal said:

I'll hazard a guess that with only 1/8" of wheel clearance, it's not shag carpet you'll be putting it on

A short shag, but a test has been run.  Had an old PC cabinet with wheels on the back edge so it could be dollied around.  Those were wood wheels I turned on my lathe, and they had only 1/8" or reveal below the posts they were attached to.  Rolled fine.  The only hazard might be that some hair or whatever else finds the floor could be caught up on the bolt axle. 

Your shag warning is one I'll add to my list of furniture properties most don't consider when designing furniture. https://4dfurniture.blogspot.com/search?q=furniture+properties

4D 

 

Carpet warning was added to that post. 

Taking inventory of the wood I have to make the reclining chair with red oak comes up short.  I have a couple of maple boards although they aren't the thickness I want to use.   Walnut I make have enough of if I skip making a walnut pedestal table with it.   I've got an outdoor teak sofa frame that might have enough useable wood in it but it's in bad weathered shape. After skimming off the weather surface of all the parts it may not be enough.   Max wood thickness I have is 7/8" actual of maple or walnut.  I'm after 2" x 1.25" parts of assorted lengths.  I can get there by ripping and tipping and gluing then cleaning up/thinning back down to the final shape, but not without more loss than just ripping would create.   Of course I could make a Frankenstein  version using whatever woods can make any of the parts.  Not a true fan of that idea. 

4D

Decided to make a 1/2 scale version first.  I found a mini linear actuator that has half the extension travel and half the total length as the larger one I found for the full sized chair.  The sides are 2 layers of 12mm Baltic Birch plywood but 6mm was easy to find.  Legs and seat/back frame are 2"x 1.25" but I have a panel of wood that is 5/8" thick that I can cut most of the parts from at half scale 1"x 0.625".   A half scale model is also easier to photograph, easier to lift and move around, etc..   I can even scale down the expected load (me) to 1/8 of my weight and use a bag of pennies to see if the small actuator can lift the chair with that load. I even found some toy wheels that are 1/2 the diameter of the full sized wheels. 

 

I'm getting quite fascinated with the linear actuators.  Don't know what I need them for other than this chair, but my creative sense now includes their potential for whatever I come up with in the future.   I'm curious if they can be micro controlled.  Need to do some research to see if they could be controlled to move a precise distance repeatedly and reliably like a stepper motor.  With only two +/- power lines used to run them back or forward I doubt these can.  Thinking of using two to move an X/Y table to specific positions for my floor standing Nova Voyager drill press.  

Parts have been arriving that I need for the 1/2 scale version. The small linear actuator can run off a 9v battery, and so I ordered some lithium rechargeable 9v batteries, and a couple 9v battery holder with wires and a switch.  Using heat shrink solder connections I've got the actuator all wired up and running reliably with a wireless control puck.  I can swap the wireless controller to my full sized version should I ever actually make one. 

Second thing that should arrive with the snail mail is some 6mm BB plywood for the disk sides.  By making the side with two pieces I can hide details (like cable slots) in the middle before connecting them. 

4D 

6mm plywood failed to show up.  Amazon refunded my money.  Tracing them they started out in Kansas, about 100 miles from me, and then went to New Jersey before disappearing. Had that happen a few times before and am suspicious that there is an address in New Jersey that matches my street and house number. 

In any case I'll be making a trip to a nearby lumber source in a few days and plan to restock my shop with project materials. I'll include some 6/4 oak to make a full sized reclining chair with in case my 1/2 scale prototype actually works. 

4D 

1 hour ago, 4DThinker said:

Amazon refunded my money

AT least that's good news