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Mon 21st Apr 2014

All the parts for the Flexibot cut out and ready for final testing.

Everything fits together nicely and the end result runs smooth as silk.

Next step, colour.

 


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Experience has shown that connecting acrylic gears to acrylic shafts is tricky. Up until now I've been cutting holes in the acrylic with the laser cutter and push fitting the gear onto the shaft. For a 6mm shaft I've cut a hole between 5.7mm and 5.8mm. Sometimes it works, and is a nice tight fit, other times the gear cracks as it is pushed into place.

My first attempt as designing a sprung connector failed when three of the five fingers snapped off at the first attempt.



My second design is simpler and hopefully more robust. I've added curves to all the corners to spread the strain.



 

Here are the first and second drafts for the gear centre design. in each, the central circle is 5.7mm in diameter. The spring of the three fingers allows a 6mm shaft to ft into place and grips it tightly.



Here are the final gears cut out and ready to go.



They work nicely, gripping the shaft and holding the gear square.


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I'm in the final stages of designing the Flexibot model. As the handle on the side of the box is turned the arms lift up and down lifted by pulling on a paper belt. The box that the robot is standing on is based on the scotch yoke mechanism.


I've removed the central shaft from the original scotch yoke design as it is not needed. As the crank turns the yoke is lifted up and down.

The paper belts that drive the arms are glued to the yoke. As the yoke moves down, the arms are pulled up. When the yoke returns to the top of its range the arms drop down again through gravity.

 


Looking good!


There are a couple of changes I need to make before the model is complete including moving the robot further back on the box. It should be a cute little model when its done!


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Thu 17th Apr 2014

The nice driver from UPS dropped me off a parcel this morning. It contained my author's copies of the second edition of Gizmos. I'm delighted, it looks great!


The from of the box features a picture of the Marching Robot, the back shows the other five models that are in pack ready for you to make. Die Fledermaus, Surfing Bunny, Mouthy Moose, Schrödinger's Cat and the Shrimp Boat.


Inside is a wire-bound booklet with all the parts and instructions.


Each model has an introductory page...


...and full instructions for construction.


Best of all, as well as the parts sheets in the book which are ready for you to cut out and make, there is a separate pack with a second full set of parts sheets pre-cut and creased, ready to pop out and make!

Gizmos is available to buy from Barnes and Noble shops. You can find out more details here.


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Tue 15th Apr 2014

Here's an interesting mashup. Our friend Mr Cool has used the interchangeable cam from the T.Rex mixed it with Guard dog dog to create this delightful model. Nice one!


Meanwhile Michael42er has produced this elegant modification to the recent Owl model. A simple cam on the vertical shaft flaps the owl turns his head. Fantastic work Michael!


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Mon 14th Apr 2014

Reading though some back posts I came across the flexbot project that I had worked on some time ago. That project project eventually morphed into the flexiphant and scotch yoke mechanisms but it seems a shame to see the original idea go to waste. To that end I've dug out the files and am now working on a completed version.

The original stop-motion animation shows how the arms will work. Paper straps connected to the insides of the wrist and running through the length of the arm are pulled down lifting the arms as they do so.

In the original mechanism I used a pair of bell cranks to change the direcion of pull.

In the new version I have run the paper straps over a
couple of paper pins as shown below. Far simpler to make.

 


I'm changing the design of the arm in the next draft. In the current version the segments that make up the arm are all equally spaced. This in turn means that the angle of turn in each section is the same. I would prefer the parts nearer the body to flex less than the extremities. To that end, I'll be closing up the gaps between the segments. The closer to the body, the smaller the gap.


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In this blog post I'll explain how I linked together two paper projects to make an Animated Paper Owl. Start with the two projects, Owl Papertoy and RRVSt2. There a couple of small pieces that you will need to make to join both parts together.

Members can download a template of the parts at the link at the top of the page. If you prefer you can make up the parts using these dimensions. Make them from thin card.

Assemble the Owl and mechanism box following the instruction on their pages. For this simple model the wings are not animated so there is no need to connect the long wing pulling tabs.


Glue a small off-cut to the back of the owl as a tab.


Glue the tab and the feet to the box so that the vertical shaft is centred within the body.


Glue together the two Owl Link parts as shown.


Glue the Owl Link to the inside of the owl's head.


Fit the square tube of the Owl Link over the circular shaft of the box. Don't use glue, a friction fit allows you to make adjustments to position and orientation.


Turn the handle and be amazed just how far the owl can twist his head!


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Add to Cart to download this kit for free !
Download Owl Papertoy

A simple but fun papertoy owl to download and make. This model can be used as a static model or with a little ingenuity, as part of a paper animation.



Everybody can download the parts for free. Have fun!


Print out the parts onto thin card. Score along the dotted lines and cut out the holes before carefully cutting out the parts.

The head is made by rolling round the head strip and gluing it down then folding down the curved flaps. No need to glue them.


If you want to make the wings move, glue the top of the strip to the back of the wing so that it just touches the crease line at the top of the wing.


Glue the fillet into place to make a bell crank as shown.


Thread the long tab through the hole in the body and glue the semi-circular tab to the grey semi-circular area. Repeat this process with the second wing.


Roll the body round and glue it down.


Glue on the feet.


Glue the head to the body to complete the owl.

Use this as a finished model or as a starting point to design your own paper animation model. I'll be demoing an idea or two in the next few posts.


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Sun 6th Apr 2014

Two YouTube videos for your delight!

Firstly. Cool022883 has produced this delightful "Cow Jumped over the Moon" model using a combination of crank slider, leaping goat and what looks like the head from the Rumination model. Nice work!

Secondly Michael42er has modified the latest RRVS mechanism and used it to charm this paper snake. Thanks both of you, I always look forward to seeing what you will do next!


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Sun 6th Apr 2014

ThePropsNerd has been at it again on the Instructables website. He had originally made a version of the Display Gears project from acrylic, this time he added an external crank to the side of the box linking to the drive gear with edge on gear. Nice work PropsNerd


On the same site a few days later, user rfairbanks uploaded his own steampunk style Display Gear using painted wooden parts and mylar gears for smooth running. The result is this intricare looking delight.

Thanks for sharing, both of you.


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