Parametric Coin/Token operated candy dispenser

thingiverse

I like the candy dispensers here, but thought that they shoud require a coin or token to access. (I didn't like the one that had one). I started out designing a coin mechanism that I could transplant onto the one I liked best and ended up designing a complete dispenser around it. Not being a trained design engineer, for me, there was a lot of work balancing use, ease of printing and assembly. It also had to be parametric and built in OpenSCAD. I think I have the right balance but welcome comments on improvement. I always try to avoid using libraries, as you never know what anyone else has installed. Items that may be subject to breakage/damage are all in the security ring. I suggest printing a spare one or two. **Some Tips:** **Body:** - Supports=yes - print the body using walls outside to in (it slopes inwards) - the bigger the body, the easier everything else fits. - the bigger the body, the longer it takes to print. - use the 'locator offset' to move the handle and its gubbins up or down **Cap:** - If you are gluing a cap into the top, you don't need threads. - I suggest printing the cap holder on its own to make sure that it fits your dispensing bottle. you may also need to make adjustments to the cap height, or even the code in the 'cap_holder()' module to suit the bottle/jar/dispenser you are using. - Use thread rotation to align containers that are not round, I used a square one. (there is a small nub at the back of the cap to help with this) **Collector/Cup:** - be conservative on the collector & cup size, it holds more than you think! - print the cup to see what you get for your money, remembering that it will be slightly heaped - the cup size can be changed almost independently **as long as you use the original collector diameter** and walls. Just reprint and replace the collector - if you want to increase the capacity of the cup, it is better to elongate it rather than increase the Collector diameter as that may reduce the height of the exit chute a little. You could reprint the funnel to accomodate the changed size, but it is not always necessary - If you adjust the cup depth, make sure this does not result in the cup punching through the collector. Keep it at least 2 or 3 mm less than the collector Diameter - Collector_offset reduces the overall length of the collector cup support by this amount. Keep at least a 10mm ring to support the cup **Coin security ring** - Supports=yes (tree, touching build_plate) - if you want thicker arms increase arm_thickness_multiplier (default=wall thickness) - If the coin latch is sticky, then round the edges of the lip just a little. - be careful when removing the supports below the coin latch and make sure ypu don't break off any of the prongs. **Coins/Tokens:** - using tokens rather than coins allows for a thicker token increasing the security and robustness of the mechanism **Handle** - Supports=yes/no/maybe depends on your printer - before you assemble anything assemble the collector and handle, then thread them by screwing in an m3 screw. Disassemble them, remembering the handle orientation, or thread both sides, so that the screw can be replaced on final assembly (use a little 'Blu tac' or similar on the screwdriver) **General:** - This is an **EPIC** print, reducing the size of the body will save loads of time, but may be top heavy, or look odd. If you have a tuned in printer, bump the speeds up a little for a dramatic improvement, (make sure wall thickness is a multiplier of your nozzle thickness - The parameters are important and there are a lot of dependencies, Make sure you have done the sanity checks and are happy with the model and saved your settings before printing **anything**. - Make sure the bed has cooled off properly before removing any parts. You definitely dont want to warp them, especially the coin plate and the security ring - I use a tolerance of 0.5mm to make sure things can move. depending on your setup, you may need to adjust this. **Before printing**, there are a few sanity checks to be performed. (the views are a little exploded here) **Check1** - Check that the coin plate (Note: it is upside down) is well inside the parabola on the face of the dispenser. If it needs moving vertically, adjust it using the 'locator offset'. If it is too big, either increase the base/top diameter and/or reduce the token diameter or support shaft diameter or change the height of the housing & offset. Here we are also checking vertical alignment of the collector & coin plate. ** Check 2** - Is the bottom of the coin slot clear of the Chute exit and security ring screws. ** Check 3** - The Chute & Collector housing.Are there any gaping holes big enough for the candy to fall through. This may be the case if it has been rotated significantly. - This may also throw a 'WARNING: Object may not be a valid 2-manifold and may need repair!' sporadically when rendering the body including the Chute, but will still print OK. At least it did for me. Remember the coin plate size is a function of the coin or token size & the support shaft diameter (runs through the collector). This means you are constrained in terms of height and width of the body. **Check 4** - do all the coin acceptor parts fit together with space to rotate? - the ratchet arms will be a very sbug fit. Thats ok. **Getting the coins/tokens out** Again, here I struck a balance between ease of use and printing. You need to tip the unit upside-down, remove the jar and funnel and tip the coins/tokens out. If the font for a token is blank, the default Openscad font is used These are some free for personal use Stencil fonts I have found : Stencil Allerta * Ombudsman Alternate * RM Playtime Stencil In Windows, install them for all users (elevated privileges needed) to make them available in OpenScad * I feel these are the nicest for those of you running windows, the file export_all.bat will read the file input.txt and export all the stl files (no spaces in the part names) this easily translates to a *NIX script **I have marked this as a WIP as I am trying to eliminate slicer supports by adding minimal supports to the body as part of the design. that said it should be print ready**