Good news is that at least one company has now inquired about licensing the design.  Learned that from an email this morning from the K-State licensing office. Nothing finalized yet, but a good sign.

The prototype looks very nice 4D.  Is the work being done by K-State being done because you are a Kansas taxpayer, an alumni, former employee, or ?

I came up with a "new" tool, really an adaptation of an existing tool, when I was working on auto restoration.  I did talk with a company about a patent and selling it but they were pretty pricey on the upfront costs... consequently I've never done anything with it.

23 minutes ago, Cal said:

The prototype looks very nice 4D.  Is the work being done by K-State being done because you are a Kansas taxpayer, an alumni, former employee, or ?

Thanks Cal.  I taught Furniture Design at K-State for roughly 4 decades.  Their patent service/interest was for any employee of the University.  Of course they have a financial interest and it is the main driver for what they decide to pursue a patent for. Any licensing/royalty profit goes 1/2 to me, 1/4 to my former department, and 1/4 to the patent and trademark office.  They will also defend the patent for its duration. 

Woke up this morning (OK, I couldn't sleep once this idea formed) with the thought of a cloth "shelf" that could hang between the two straps. It would have sewn slots that the straps slide through. Lift the table top to reveal whatever you've put on the shelf.  Pencils, a notepad, a deck of cards, whatever.  Area would be 12" wide and roughly 6" deep.  This would work/be accessible in both positions of the top (flat or slanted). Loose, with a flap that hangs forward over the stretcher.  A hidden pocket under the top. Of course you would need to empty it if you fold flat the table to store. 

I might get bored enough today to mock this up. I have material and a sewing machine. All I need is a place to set up the sewing machine.  Hmmm.

Up there, between the straps.  The top can be rotated up to access whatever is in there. 

4D  

Edited March 9, 20242 yr by 4DThinker

Lifted up view:

I discovered in comparing my two versions that they don't spread the legs/tilt the top the same amount in the slanted position. 

The cable between the legs below the pivot bolt fixes the angle between them the same in both positions. 

The straps above gain a 1.75" shift between positions due to the offset in the legs that allows the stand to fold flat. The legs stick forward a bit farther than they should in the slanted position. 

I may make a 3rd prototype, and look into changing where the strap comes out of the stretcher.  Coming out of one side, the strap would run directly to the back edge of the top.  In the other position the strap would have to go over the stretcher before running to the back edge.  Some drafting in my CNC software and I should be able to steal 1.75" from the strap path in the slanted position.  Compare legs/slant between the two below.

4D

I have to give my CNC software some credit for the great measuring features it has. Aspire from Vectric.com.

 

This a clip from the software showing the table in both positions. In each I drew a vector path for the strap. Measured each and compared the difference.  Adjusted end position of one closer to the length of the other and rechecked.  Repeated until they are within .002" of each other.  Now I know where to make a slot on the side of the top stretcher to slip the strap end into. As it wraps over the stretcher and runs to the back edge of the top it is exactly the same length as it is in the other position where it runs straight back from the stretcher to the back edge.  The legs now will be the same distance apart in both positions. 

Now debating (with myself) whether to make another prototype from cherry or maple. Any preference out there? These are the woods I have on hand. 

4D

Both Cherry and Maple would work but I like Cherry for this.

Looked around my garage shop for a piece of red oak I could use to just make a new top stretcher.  No luck with oak.  Did find a scrap of what I believe is mahogany that was very close to the desired dimension so I ripped a little off to make it 2" wide.  Ran it through my drum sander to reduce to 5/8" thick.  My router table still had a 5/16" radius round-over bit in it so I used it to bullnose the top and bottom edges of the mahogany/new stretcher.

It did have a couple of screw hole in one side, so I bored them out with my new 3/8" forstner bit, then made some plugs to fill the holes. Sanded down you can only tell they are there from the black iron stain still slightly evident around them from the previous steel screws. 

Use my CNC to cut tenons on each end.  Still need to make matching mortises where they mount in the frame sides. 

What is left after that is two slots for straps and 2 holes so a screw can drop through a grommet in the ends of the straps to hold in the slot. Follow with two new straps, slightly longer than the initial ones.  

Edited March 10, 20242 yr by 4DThinker

Got the two bolt holes done.  The hole needed to be 13/16" diameter, and straight down from the top center of the stretcher.  I've got a self-centering drill guide, but it only has bushings for 1/4, 5/16, and 3/8" drill bits.  Then I remember an old port-align drill guide I had. A Black and Decker electric drill mounted in it.  Found it. Found the chuck key.  A bit abused and stiff so the guide posts got a little WD-40 lubrication to ease the sliding.  Drill still ran, but sparked a bit when running.  Might need new brushes.  In any case it did the job.  

 

I still have to make slots for the straps.  Playing with an old tool sent me down memory lane though to a time when I didn't have a CNC but still managed to make whatever I imagined with the tools I did have.  The slots I could cut on my CNC, but also on my faithful router table in the garage.  Toolpaths vs tape with measured marks on it. About the same effort to load the right bit into a router. Too many fussy steps such as clamping down, aligning, zeroing, files saving and loading and running, etc., with the CNC.  Now that the garage is warming up I don't mind working out there.  Hmmm.... 

On 3/9/2024 at 3:43 AM, 4DThinker said:

Lifted up view:

 

without that top, it looks like an old luggage rack you used to find in hotels.

Just now, DAB said:

 

without that top, it looks like an old luggage rack you used to find in hotels.

Yep.  I had the same thought.  Those were simple X frames though, while my asymmetric X lets the short legs swing under the long to invert for the second position.  I suppose you could still use mine as a place to set your luggage on though, either version straps or cable.

Last post for the day.  Keyboard wants to go to bed.

Went from an idea yesterday morn to a working prototype of the idea. 

Old stretcher cut out using my bandsaw. Flush trim bit in my router table trimmed flush the 1/16" or so I'd left against the side legs. 

Hunted down a useable wood scrap.  Found a scrap of mahogany that was salvaged from some old deck furniture that would work. 

Trimmed it 2" wide. Drum sanded it down to 5/8" thick.

Cut it to length using my Bosch Glide chop saw. Left 3/8" on each end for tenons.

Used my CNC to cut the tenons on both end.  Used my CNC to cut matching mortises on the inner side of the legs. 

Used a 5/16" roundover bit in my router table to bullnose the top and bottom edges of the new stretcher. 

Drilled a shallow 3/8" diameter recess in the top of the tenon for the heads of the binding bolts that would pin the straps in place.

Followed that with a 13/16" drill bit down the center to intersect future straps in a slot.

Used my router to make both slots for the straps.  1/8" spiral bit in 5 steps up.

New straps needed.  Cut new pieces.  Singed both ends to keep them from unravelling. Punched holes in both ends of each for grommets. Extreme care was taken to make sure the distance between grommets was exactly what my CNC Software dictated. 

Put the stand together, with the new stretcher in place but not yet glued.  Fed the new straps into slots, pinned in place.  

Stood stand up.  Slanted position. 14.375" between front and back legs.

Flipped the stand inside out to flat position.  14.375" between front and back legs. 

Yee Ha!

Love it win an idea works.  Photos tomorrow.

4D.   Goodnight! 

Old vs new.  Side Views before and after.  Strap paths flat vs slanted orientation.

Edited March 11, 20242 yr by 4DThinker

Lesson:  Prototype.  Test.  Prototype again.  

1. TV tray table with ball chain as the tension member between the legs.  1st ball chain tried broke.  Tried better rated ball chain.  Worked, but cludgy.

2.  Had the idea to use a straps at the top rather than cable or ball chain at the bottom.   Broke out the top stretcher to make slots for the straps.

3. Put frame back together to evaluate. 

4. Studying initial strap prototype I found out that initial path for straps at the top wasn't ideal for the geometry of the design.

5. Cut out top stretcher again after finding a new potential path for the straps that would solve problem discovered in 4 above. 

6. Put frame back together to evaluate. Seems to work much better. Put it to use to see if any other flaw shows up. 

Confident now that if I make any more of these I know the geometry better and the best way to tension it in both positions. 

 

This is not uncommon with my personal designs. Iteration always leads to better solutions. Good ideas deserve a prototype to prove they work or don't. If they work but not "perfectly" that will usually point to a better solution. Prototype again and re-evaluate.   If it doesn't work then restart with a new idea.  Time spent helps set an idea in memory, where another application for that idea may pop up later.   Bonus idea this week was capturing strap ends with a pin/bolt through a grommet in the strap.  I'll use that idea again. 

4D

   

I know now that straps at the top can work. I woke up wondering if straps instead of cable would work at the bottom.  My prototype with tension cable is an imperfect, fussy solution.

Daylight brought an idea for how to use straps between the legs, but a mock up was necessary to prove that the strap would work this way.  This is some scrap board found in my garage. I call it branch wood as I cut it from a branch of a tree that a mini-tornado dumped in my yard. 

I can use the holes I made for cable, enlarged for a binding bolt.  Slots cut in the front face of the legs, oversized to allow for the angled approach, and straps with a grommet in the ends. Binding bolts pin the strap in place. Photos show it in what would be both positions of the top. 

 

I know that using straps in furniture is uncommon. A package of grommets with a hole punch and plyers to set them was extraordinarily cheap.  Strap is also cheap if bought in 50ft or longer rolls. Strap is also available in different colors.  Strap can be easily replaced as the binding pins holding them in can unscrew and drop out. 

If I had to make 50 or 100 of these tables I'd rather use straps than the cable. I also feel like the straps will do less damage to the wood legs than the cable might wrapping around it. Cable was fussy to install and hard to remove. 

4D

Edited March 13, 20242 yr by 4DThinker

I personally like the looks and idea of the straps for reasons you noted as well as the aesthetics plus gives a possible decor option with different colors both with the legs and the top.

Thanks GPD52. Using or just leaving the stand set up the straps under the top aren't seen. The straps between the legs where the cable was are out there to see unless you are in front with the table pulled up to you to use. 

Many years back I had a summer furniture class student design a chair that used rows of red webbing for the seat and back. Light maple sides.  The chair got accepted into a national competition, but its base was rough with stretchers held to the sides with drywall screws. Knowing the competition judges looked for woodworking craft details I rebuilt the base for the student.  New base had stretchers using through wedged tenons, and to match the red strapping I used bloodwood for the wedges.   The chair won first place in seating and the judges mentioned that wedge detail gave the chair a high score for design/craft. 

On my ash version that currently uses cable between the legs, I embedded square nuts for the bolts to thread into.  Covered the nut pockets with a CNC cut wood plug.   Those plugs would be a nice detail done in a wood color that matched the strap color. Just a spot of detail continuity.   Even the binding bolt heads could be painted a color to match the straps.  

Can't resist iterating it seems.  Ordered some 3/4" wide green polypropylene webbing.  When it arrives I plan to replace the cables on my ash version with it. The 1" wide strap worked fine in my mockup, but I'm thinking the 3/4" wide will be plenty strong enough and better balance the visual composition with the 7/8" wide/thick legs. Green shouldn't look bad with the ash wood and will provide a little color pop just to make people notice it. 

4D

Got bored yesterday and glued up some cherry to make a new TV tray table top.  Haven't got the slightest idea why I need another one.  I'll change the details a bit from the other two so they each have something unique about them. 

Needs some scraping and cleanup before I'll run it through my drum sander.   Should end up  clean and smooth at 7/8" thick. 

4D