Rise and Fall Clock

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Warning this project is not finished and doesn't work in its current form

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For a while I have had an idea of making a clock that would slowly get taller as the day went on then would fall back down again which would give a good visual representation of the passing of the time. But how to power this device, Mechanical winded clockwork too complicated with too big a chance of failure, a synchronous motor good torque but requires connecting too the mains electricity supply so outside of my skill set. All seem lost til I happened to come across a YouTube video by the genius that is Mojoptix (of the digital sundial fame) he demonstrated the use of a cheap mass produced battery clock mechanism as way to slowly revolve a model or use it as a cheap mechanical power source. So with that I set too the task of designing.

This project is mainly 3D printed with a short list of components some of these can be changed with a little tweak of the OpenSCAD file

BOM

roughly 350g of filament which makes two parts the Base and the Rising part (the riser)

5/32 K and S Brass square tube.

continous reverse clockwork mechanism

AA battery

Small piece metal/plastic (shuttle)

Tools

3d printer

A metal saw

Hammer

Centre punch/chisel

needle file

I considered many designs using gears, pulleys and racks but being a fan of the KISS principal I settled on a simple screw mechanism with a shuttle pin (referred from now on as shuttle) that would engage when in the lower position and be forced out at the top allowing the screw to fall back down. where the pin would be pushed to engage the screw again. OK the working principal decided on how to put lipstick on this pig. I wanted it to be a sleek minimalist design so I wanted to hide the screw mechanism. I also wanted a way to show the time in 5 minute increments at the minimum. So after a few designs and a lot of dedicated cognitive runtime (instead of sleep) I landed on the design you see here. does it work well sort of but more on that at the end.

The first thing is print the two 3D parts this can be done by downloading the text file and copying it into a new OpenSCAD file. Once saved OpenSCAD file change the flag value to 2 render and then export the STL then do the same for Flag value of 3. these are long prints even at standard fast settings it took me roughly 16 hours to print each piece.

Tips for printing

The Base is printed the right way up with supports to help with the bridging for the space for the clock mechanism. The Riser is best printed upside down without supports. make sure the Z seam position is set to random With them printed and any supports removed its time to assemble the device.

The Clock Mechanism

 We need to cut the the brass tube to length It needs to be 124mm long. if you change the OpenSCAD file you may need to change this length. once cut to size slide the tube over the minute hand stub on the clock mechanism. to ensure drive I considered gluing it on but was worried it would glue the mechanism in place and stop its functionality. so if in doubt give it a clout. I used a hammer and a centre punch to collapse the brass tube onto the drive, but you could use a small chisel or anything just be careful not to damage the mechanism. the clock mechanism is not very powerful so it doesn't require loads of holding power. Place the clock mechanism into the base and fix in place with the supplied nut sliding the washer and then the nut down the brass rod. this is tricky to tighten but with a screw driver I managed it. it doesn't need to be tight as the base will stop it from rotating its just to stop it falling out if picked up. lower the rising part into the base can be tricky to align with the brass tube. The easiest way I found was to invert both pieces and lower the base onto the riser this allows the brass tube dangle more vertically with the assistance of gravity, if it doesn't slide on check the position of the tube and adjust till it is central. The rotational position of the riser is not important at the moment as long drive hole is aligned to the brass tube so it can slide onto the brass tube.

The Shuttle

the shuttle is made from either from plastic from a old credit card or a small piece of metal. it needs to slide through the slot and be just long enough to touch the bottom of the screw and the inner wall of the Riser part it is measures 15mm by 5mm and is 1mm thick. It has a rounded corner on one side as can be seen in the picture. Now we need to install the shuttle, this is done by winding the clock mechanism forward and raising the riser til the slots line up. when aligned insert the shuttle doing this while tilting the clock horizontally makes it easier. note the direction of the chamfer. It made need a little help dropping in so its OK to give it a little help but it needs to move freely so it might need removing and the slots cleaning up with a needle file or hobby knife etc. once fully inserted winding the clock forward again the Riser should start to rise up. 

Now for the moment of truth install the battery and set to the correct time. place on a flat surface and marvel as the riser slowly raises it self up.

As stated at the start this isn't a finished project it needs some more work. might need redesigning completely maybe in Fusion360 or TinkerCAD. I just don't have the time or resources to dedicate to this anymore but I would like to see what other people can make of this. all I ask is a credit somewhere.

Key Problems

The motor doesn't have enough power to lift the Riser. I think this is for 2 reasons, firstly the step height of the 3D print produced steps in the screw(at least I didn't see them in the 3D model) secondly when the Riser nears the top it tilts and bind. This could be solved by including a bearing surface in the base as can be seen in the OpenSCAD files.

Improvements

I have had some ideas for ways to improve it. these include

• using printed paper for the outer walls this would speed up print times and reduce plastic usage it would make the Riser lighter making it easier for the clock mechanism, It would still need a track for the shuttle to run in but its doable.
• incorporate a led light in the inner wall to shine through the riser outer wall.
• make the riser wall a lithograph combined with the above light idea would look cool
• make the riser out of colour changing filament to show more clearly the time (if printed correctly could have a colour for each hour that passes)

what would you like to see?