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mechansim

Co-axial Gear 2:1

£2.50

Your rating: None (3 votes)

Co-axial gear with 2:1 reduction.

This Essential Mechanism is an evolved version of the original Co-Axial Gearbox from here. While I was designing the forthcoming rotating robot model I felt it would be better if the robot rotated a little slower so I have increased the size of the main gears on the original co-axial gearbox so that there is now a roughly 2:1 speed reduction. The mechanism will, I'm sure, be useful for other projects so I decided to release it as an Essential Mechanism. Turn the handle on the side of the box and the outer vertical shaft turns one way while the inner shaft rotates the other.


Members can download the model for free from the link, thank you for your support! Non-members can join in the fun for $3.75/£2.50

Download the file and print out the pages onto thin card (230 micron / 67lb) I used coloured card for a colourful model. You can use white, patterned or colour card as you see fit.

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


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


Fold up the the box top and base making right angled triangle tubes.


Fold over and glue the tabs on the ends to make triangular tube.


Roll over and glue all three tubes. Line up the edges with the arrow points as accurately as possible.


Fit the small stub into the nine tooth pinion.


Fit the short 8mm axle into the pinion and glue it so that it protrudes roughly 5mm from the other side.


Fit the axle stub into the large gear with the small hole.


Fit the long 8mm axle into place so that the grey area is inside the stub. Make sure the gear is a straight and flat as possible.


Fit the axle stub into the remaining gear.


Glue in the 10mm tube again lining it up with the grey area and again keeping the gear as straight as possible.


Thread the two axles one inside the other. No glue! They must be free to rotate.


Assemble the handle in three steps.


Glue the the two ends to the base. Note carefully the relative orientations of the three parts.


Glue one end of the top into position but leave the other end unglued.


Thread the axle up through the box top then fit the other end into the box base.


Thread the pinion into place in the cross piece.


Thread the short axle out through the box end.


Close up the box and glue the remain top edge to close the box.


Fold in the sides and glue them into place.


Glue the end tabs of the cross piece to the outside of the box.


Fit the cover piece into place.


Complete the mechanism by adding the handle to the box.

Use the model as an exercise in pure mechanism or as the starting point for your own paper animation automata. Look out for the Rotating Robot coming soon!

Co-axial gear with 2:1 reduction.

This Essential Mechanism is an evolved version of the original Co-Axial Gearbox from here. While I was designing the forthcoming rotating robot model I felt it would be better if the robot rotated a little slower so I have increased the size of the main gears on the original co-axial gearbox so that there is now a roughly 2:1 speed reduction. The mechanism will, I'm sure, be useful for other projects so I decided to release it as an Essential Mechanism. Turn the handle on the side of the box and the outer vertical shaft turns one way while the inner shaft rotates the other.


Members can download the model for free from the link, thank you for your support! Non-members can join in the fun for $3.75/£2.50

Download the file and print out the pages onto thin card (230 micron / 67lb) I used coloured card for a colourful model. You can use white, patterned or colour card as you see fit.

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


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


Fold up the the box top and base making right angled triangle tubes.


Fold over and glue the tabs on the ends to make triangular tube.


Roll over and glue all three tubes. Line up the edges with the arrow points as accurately as possible.


Fit the small stub into the nine tooth pinion.


Fit the short 8mm axle into the pinion and glue it so that it protrudes roughly 5mm from the other side.


Fit the axle stub into the large gear with the small hole.


Fit the long 8mm axle into place so that the grey area is inside the stub. Make sure the gear is a straight and flat as possible.


Fit the axle stub into the remaining gear.


Glue in the 10mm tube again lining it up with the grey area and again keeping the gear as straight as possible.


Thread the two axles one inside the other. No glue! They must be free to rotate.


Assemble the handle in three steps.


Glue the the two ends to the base. Note carefully the relative orientations of the three parts.


Glue one end of the top into position but leave the other end unglued.


Thread the axle up through the box top then fit the other end into the box base.


Thread the pinion into place in the cross piece.


Thread the short axle out through the box end.


Close up the box and glue the remain top edge to close the box.


Fold in the sides and glue them into place.


Glue the end tabs of the cross piece to the outside of the box.


Fit the cover piece into place.


Complete the mechanism by adding the handle to the box.

Use the model as an exercise in pure mechanism or as the starting point for your own paper animation automata. Look out for the Rotating Robot coming soon!

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Gears from the Greeks

Your rating: None (3 votes)

Back from my trip to Frankfurt, a parcel was waiting for me from Amazon. Inside was this fascinating looking booklet about the incredible Antikythera Mechanism, a gear based computer created by an Ancient Greek over 2000 years ago. The book looks great, the first few pages read well and it is packed with information and diagrams. I'll post a full review when I'm done but in the mean time you can order your own copy from  Amazon UK || Amazon US

INTERESTING LINKS

Curta Mechanical Calculator.

Antikythera Mechanism:

Back from my trip to Frankfurt, a parcel was waiting for me from Amazon. Inside was this fascinating looking booklet about the incredible Antikythera Mechanism, a gear based computer created by an Ancient Greek over 2000 years ago. The book looks great, the first few pages read well and it is packed with information and diagrams. I'll post a full review when I'm done but in the mean time you can order your own copy from  Amazon UK || Amazon US

INTERESTING LINKS

Curta Mechanical Calculator.

Antikythera Mechanism:

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Interchangeable Cam

£2.50

Your rating: None (24 votes)

Downloadable interchangeable cam model. Build the model and learn first-hand how cams work! If you are a member, first of all, thank you - I couldn't do this without you! Secondly, as a member you can download the parts at the end of this blog post. None members can download the file for a modest fee, for which, thank you as well. Print the parts out onto thin card (230 micron / 230 gsm is perfect) 

Score along the dotted lines and cut out the circular holes before cutting out the pieces. (Don't cut out the square hole in the box top. Follow the instructions below to complete the model.

The completed Interchangeable Cam model.

Fold round and glue down the box top as shown above. Make sure that the end touches the crease line at the point arrowed. Set it to one side to let the glue dry completely.


Fold over the cam and glue it together. Make sure you don't get glue on the four tabs.


Cut out the cam.


Make up the cam shaft and glue the cam in place, make sure that the orientation is the same as in the picture.


Fold round and together the two box stiffeners. Glue them to the inside of the box parts so that they are just above the circular hole.


Glue the two box halves together as shown.


Retrieve the box top, carefully cut out the square hole through both layers of card.


Glue the top and bottom of the box to the box, use the grey areas for alignment.


Make up the cam follower and and the push rod.


Thread the drive shaft through the two holes in the box. Note the square grey areas are to the back of the box. Glue on the washers making sure that the drive shaft is free to rotate.


Assemble the handle in three steps. Fold round the handle parts to make a square section. Fold one section into the other and glue down. Roll round the long tab and glue it down.


Glue the handle to the drive shaft.


Glue the cam follower to the box top then glue the push rod to the cam follower.


Complete the model by slipping the cam into the drive shaft. 


That's it! Turn the handle, the cam turns and the cam follower moves according to the shape of the cam. Find out more about how cams work in the mechanisms section.


The kit comes with four different cam profiles shown above as well as a sheet of blank cams for you to design your own. Use the model to help you design cams for your own models!

Part of the Paper Mechanisms Multi-Pack - Buy and save! 

Downloadable interchangeable cam model. Build the model and learn first-hand how cams work! If you are a member, first of all, thank you - I couldn't do this without you! Secondly, as a member you can download the parts at the end of this blog post. None members can download the file for a modest fee, for which, thank you as well. Print the parts out onto thin card (230 micron / 230 gsm is perfect) 

Score along the dotted lines and cut out the circular holes before cutting out the pieces. (Don't cut out the square hole in the box top. Follow the instructions below to complete the model.

The completed Interchangeable Cam model.

Fold round and glue down the box top as shown above. Make sure that the end touches the crease line at the point arrowed. Set it to one side to let the glue dry completely.


Fold over the cam and glue it together. Make sure you don't get glue on the four tabs.


Cut out the cam.


Make up the cam shaft and glue the cam in place, make sure that the orientation is the same as in the picture.


Fold round and together the two box stiffeners. Glue them to the inside of the box parts so that they are just above the circular hole.


Glue the two box halves together as shown.


Retrieve the box top, carefully cut out the square hole through both layers of card.


Glue the top and bottom of the box to the box, use the grey areas for alignment.


Make up the cam follower and and the push rod.


Thread the drive shaft through the two holes in the box. Note the square grey areas are to the back of the box. Glue on the washers making sure that the drive shaft is free to rotate.


Assemble the handle in three steps. Fold round the handle parts to make a square section. Fold one section into the other and glue down. Roll round the long tab and glue it down.


Glue the handle to the drive shaft.


Glue the cam follower to the box top then glue the push rod to the cam follower.


Complete the model by slipping the cam into the drive shaft. 


That's it! Turn the handle, the cam turns and the cam follower moves according to the shape of the cam. Find out more about how cams work in the mechanisms section.


The kit comes with four different cam profiles shown above as well as a sheet of blank cams for you to design your own. Use the model to help you design cams for your own models!

Part of the Paper Mechanisms Multi-Pack - Buy and save! 

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