Experiments with intermittent drive.

Both gears have ten teeth, the larger drive gear is based on a seventeen tooth gear with seven of the teeth removed. The mechanism works as it is but the vertical shaft really needs a support at the top end. Turn the handle and the vertical shaft turns a full turn, stops for a bit, turns a full turn etc...


In the second draft the top of the vertical shaft is held in place. Works a treat! In the next version I will move the drive gear to the opposite side of the mechanism, it moves side to side a little as the handle is turned which can cause the teeth to disengage. Moving it to the other side of the box should solve this problem.


With the gear on its side like this you can visualise it driving a crank with a character of some sort on the top.

By changing the number and spacing of teeth all sorts of different motion configurations will be possible.


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Sat 10th Jan 2015

Rise of the Mammals automata prototype. The dinosaur moves slowly up and down inspecting the shrew. The dinosaur is driven via via a reduction gear. The shrew is connected to a small cam on the handle drive shaft and twitches quickly up and down.

The main gear is based on the reduction gear box here and the dinosaur is a modified version of this model of an eoraptor.

There were some small mammals at the end of the age of the dinosaurs but I'm making no claims to the scientific accuracy of these characters!


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Wed 7th Jan 2015

robives.tumblr.com The latest part of my expanding social media empire! I snagged the robives name on Tumblr some time ago, I've finally got round to setting it up to see how it goes.
I see Tumblr as sort of half way between Instagram and Facebook, it will let me quickly upload pictures and progress reports with higher quality images than Instagram and less tangle than Facebook.

It will mostly be paper engineering as that is most of what I do but I'll also add anything else that catches my interest of occupies my time, things like laser-cutting or coffee machine mods...

Visit my Tumblr page here and let me know what you think!


For ease of access I've added a button to the header on this website. Simply click the 't'.

 

And don't forget that you can also follow what I'm up too on these other social media platforms...

Twitter Instagram YouTube Facebook Pinterest

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I've just completed the parts layout and photography for a second two stage reduction gear box. I'll be posting it to the website in the next day or two. Meanwhile, here's one of the assembly photos to keep you going...


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Essential Mechanisms

A two stage gear with crank output. Turn the handle on the side of the box and the crank turns slowly. The gear box works in two stages at each stage a nine tooth gear drives a seventeen tooth gear. The output stage is driven at 1/3.57th the speed of the drive handle.


Members can download the parts for free at the link. Thanks for signing up!

Print out the parts onto four sheets of thin card. (230 gsm / 67lb) I've used pre-coloured card to make a colourful model.

Score along all the dotted and dashed lines and cut out the holes before carefully cutting out the parts.


The gears are all made from double thickness card. Fold them in half and glue them down. Once the glue is dry carefully cut them out.


Roll up and glue down the five tube sections. Line up the end of the tube with point of the arrow heads on the tube sides.


Assemble the two crank pieces as shown.


Find the large gear with the offset square hole. Fit the crank piece into place gluing it to the grey area. The short end of the crank goes through the hole.


Make up the two push rod ends from double thickness card. Once the glue is dry carefully them out.

Thread the longer of the three crank tubes through the push rod ends. Assemble the push rod tube then glue the push ends into place on the grey areas.


Fit the crank pieces to the push rod tube then glue the other two axle tubes into the open ends of the crank pieces as shwon in the picture.


Assemble the three parts of the drive gear as shown.


Glue together the box base and box top - the edges are right-angle triangles.


Glue the centre piece into place in the box base. (The one with only one hole)

Glue two tabs onto one side of the base and the other two onto the other side.


Fit the second small gear to the link tube as shown lining up the edge of the tab with the end of the tube.


Thread the link tube through the hole in the centre piece with the small gear closest to the centre of the box base. Glue the second large gear to the link tube. Make sure that the gears are free to turn.


Fold in the various tabs on both of the box-end pieces to make triangular tubes.

Glue the box end without the side cut-outs to the tab on the base nearest the large gear.


Thread the drive gear into place in the box-end then fold up the box end and glue it to the base.


Repeat the same process with the other box-end, don't glue the sides down yet.


Fit the box top into place. Make sure the centre piece is glued into place in the hole in the box top.

Glue the ends to the top then glue the sides into place to complete the box.


Assemble the handle in three stages as shown.

 


Complete the model by gluing the handle to the drive shaft.


Once the glue is dry, turn the handle and marvel as the gears mesh together driving the crank!

Use this model as an exercise in pure mechanism or as the starting point for your own character based models


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Wed 31st Dec 2014

Further experiments with gear mechanisms. This mechanism is a reduction gear, reducing the rotation of the output by roughly three to one. I'm pleased with how these gear box experiments are going. I've tried all sorts of different types of paper gears over the years with varying degrees of success. I think these gear boxes, based on the mesh gear idea are finally a type of gear ideally suited to paper engineering.


This gear box reduces the output speed in two steps. The handle is a nine tooth gear driving a seventeen tooth gear. The output from this goes again to a nine tooth gear driving a seventeen tooth. In this prototype the final output is connected to a crank. The output speed then is 9/17 x 9/17 or 1: 3.57

The movement is smooth and positive and the model, with a few small changes, goes together easily. I'll be releasing this and the other gearbox as a download very shortly.

I'm enjoying this!


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If you've been following along on Instagram you'll have seen this gear mechanism as I've been working on it. Check it out in animated action here.

 

5.6:1 reduction gear box. Final prototype. #papertoy #papercraft #automata #gear #mechanism #paperengineering

A video posted by Rob Ives (@robivescom) on

 


This is a two stage reduction gear. Both stages use the same pair of gears. A nine tooth gear meshing with a nineteen tooth gear giving a reduction of 19 : 8 or 2.375 : 1

The two gear sets are chained together. To work out the final output speed you simply multiply the two ratios together. 2.375 x 2.375 = 5.640625 So the output crank turns at just about 5.6th the speed of the input handle. (Not 5.3 as I incorrectly wrote on my Instagram comment. Grrr!)


You can see the input gear more clearly on this picture.


And here is the finished thing.

I'm away for a few days now but as soon as I'm back I'll be adding this as a project. I'm really pleased with how these mesh gear mechanisms are working out, I feel like I finally really have a grip on paper gears!


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Just in time for Christmas! Turn the handle on the Flying Santa and his arms flap as he bobs and swoops through the frosty winter air. Three flaps for each bob. Ho ho ho!

Members can download the parts for this model for free at the link. Thanks for signing up! Non-members can join in the fun for £2.50.


Print the parts out onto thin card. 230 gsm / 67lb. The coloured version of the kit is printed on both sides of the sheet. Print one side, flip the card over then print the other side on the back.

Once the ink is completely dry, score along all the dotted and dashed lines and cut out the holes before carefully cutting out the pieces.


Notice that the nose and moustache are cut round the edges and lifted out a little to give a 3D effect.

Roll the head round and glue it down.


Curve the hat into a cone and thread it up through the head. Glue the bobble into place.


Glue the small tab to the back of the head.


Fold over and glue down the arms and legs to make double thickness card.


Fold over and glue together the push rod ends and cams to make double thickness card.


Cut them out once the glue is dry


Glue the arm push rod to the arm as shown.


Fold up the body inner.


Glue together the three parts of the body.

Fit the body inner into the body.


Thread the arm push rods and arms through the holes in the side of the body and glue them to the tab. Make sure that the arms are free to flap up and down.


Glue the tab on the back of the head to the grey area on the back of the body.


Assemble the leg support parts and glue the legs into position.


Glue the legs into the body.


Roll up and make the various tubes lining up their edges with the arrow points.


Assemble the push rod. Glue the push rod end into place with the shortest tube threaded into position.


Assemble the two crank pieces.


Thread the two cams onto the crank pieces and glue them down.


Glue the crank pieces to the centre axle. Make sure that they are lined up.


Fit the two axle tubes into place.


Glue together the two parts of the cam follower. Thread the cam follower tube into place and glue it down.


Make up the four spaces by folding in half and gluing down the small rectangles making four double thickness squares.


Thread the cam follower down onto the push rod. Don't glue it! It must be free to move up and down. Glue two spacers into place on the end of the slider tube as shown.


Slide the other two slider tubes into place. Glue the two remaining spacer pieces onto the second slider tube as shown.


Assemble the link pieces and use them to join together the two spacer pieces on each side. Make sure no glue gets onto the centre slider tube.


Assemble the box top and box base by make triangle section tubes.


Assemble the two box sides by making right angle triangle tubes.


Join the four box pieces together. Use the picture to ensure they are in the correct order.


Thread the push rod assembly up through the box top and glue the centre slider tube to the box top tab.

Fit the axles through the holes in the box sides.


Fold up and complete the box keeping everything as square as possible.


Assemble the handle in three steps as shown.


Glue the handle into place. Notice that the cam follower assembly is at the front and the handle is on the right.


Tightly fold up a couple pennies (4 grams each 20mm diameter) into an off-cut of card.


Glue the coin bundle to the front of the cam follower.


Thread Santa down onto the top of the push rod. He should be facing towards the front where the cam follower and coins are.

Glue the ends of the arm push rods to the top slider tube.


That should do it! Turn the handle and Santa will flap his arms three times for each time he swoops. Ho ho ho!

 


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If you follow me on Instagram you will already know about this new model. You do follow me right?

Flying Santa! Coming Soon! All the photography and parts are done, just the instructions to write. Ho ho ho!


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Co-axial Gear.
Essential Mechanism.™
Here's an interesting mechanism for you to download and make! Turn the handle on the front of the box and the planetary gear reduces the output speed by half.
Use it as a stand-alone paper mechanism or as the drive for your own paper animation kit.
Members can download the parts for free from the link, non-members can join in the fun for £2.50

 


Print out the parts onto thin card (230 micron / 67lbs) Coloured card makes for a colourful model.

Score along all the dotted and dashed lines and cut out the holes before carefully cutting out the pieces.


The four gears are made of double thickness card. fold them in half and glue them down. Once the glue is dry carefully cut them out.

 

 


Roll up various tubes and glue them down, carefully line up the ends with the arrow.

 


Assemble the two parts of the cross piece.

 


Fit the long 8mm tube into the cross piece lining it with the square tube between the two grey lines.

 


Glue the other two 8mm tubes into place.

 


Fit the square section into the pinion gear then fit the short tube into place using the grey lines for alignment. Repeat the process with the second pinion gear.

 


Thread the pinion gears over the 8mm tubes. They should turn freely. Glue the end stops on to hold the pinion in place without stopping them from turning.

 


The completed pinion assembly.

 


Glue the four spacers to the grey areas on the large fixed gear. Fold the spacers up and glue them to make a shallow box.

 


Assemble the box front and back.

 


Glue the fixed gear into place in the hole in the box back.

 


Thread the pinion assembly into place so that the gears mesh with the fixed gear. The assembly should be free to rotate.

 


Fit the square tube into place in the large gear using the grey line for alignment.

Fit and glue the remaining tube into place lining it up with the end of the square tube.

 


Fit the large gear into place as shown. Don't glue it! It should be free to turn over the pnion assembly.

 


Assemble the two box ends.

 


Thread the box front into place over the axle.

Glue the two box ends into place as shown.

 


Assemble the handle in three steps.

 


Glue the handle to the shaft as shown. Let the glue dry completely.

Turn the handle and the mechanism turns the output shaft at half the speed of rotation of the handle.

 


To make it easier to see the rotation of the output shaft assemble this push-to-fit hand. Once the glue is dry, slip it over the output shaft.

 

 


The input and output shafts are lined up so you can daisy chain more than one of the mechanisms. Each gear divides the rotation by a further two times.


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