Three Cams and Gear

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Three cams and gear box – Turn the handle and the gear turns, driving the cam shaft and the three cams. Download and make this Essential Mechanism as a exercise in pure mechanism or as the starting point for your own character based paper animation.

Print out the parts onto thin card (230gsm /67lb) I used coloured card for a colourful model but you could use white card or print a pattern onto a sheet of plain card before printing out the parts.

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

Fit the short axle tube into the pinion gear lining it up with the grey line.

Glue the cam shaft to the large gear.

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

Fit the cams to the cam shaft arranging them so that they are offset by 120 degrees.

Roll up and glue down the three axle tubes. Line up the edge of the tube part with the edge of the grey area and the points of the triangles..

Make up the box end.

Fold round and glue down the triangular tubes on the side of the box top and box base.

Fold in the sides of the box end and glue them down making right angled triangles

Glue the box end to the base – note that it glues to the end with the larger space on the triangular tabs.

Glue the box top to the box end.

Fold round and then glue in the other box end.

Glue down the flaps to complete the box.

Fit one of the short axle stubs into the cam shaft.

Fit the gear and cam shaft into the box then locate it into place with the other short axle stub.

Fit the pinion gear to the end of the long axle.

Assemble the handle in three steps.

Roll round and glue down the gear locater.

Fit the gear locater onto place so that the gear is held up against the box side but is still free to turn. Thread the long axle and pinion into place so that the pinion engages the large gear.

Glue the handle into place at the front of the box.

Assemble the three cam followers.

Fold over and glue down the three push rods make a double thickness shaft with a tab at each end.

Glue the push rod to the cam follower.

Fit the three cam followers into place using the grey areas for alignment.

And there it is! Click the picture below to see an animated version on Instagram.

Next time! I’ll show how you can make this charming reindeer automata using this project and the reindeer paper toys from the previous post.