Small manual turntable like a sushi conveyor belt: utilizing space under shelves

Addendum

At the end of this description, I have added instructions on how to freely change the length of the parts. Please see this if you need longer parts

Overview

I created a small manual turntable inspired by conveyor belt sushi

The minimum footprint size is 300mm x 155mm

It can also be extended in 30mm increments using extension parts

This turntable is intended for use in narrow spaces with depth, such as under shelves, to make items at the back more accessible

You could also place small plates or sushi on it and play sushi chef

Since it is designed to be placed under shelves, the knob for rotating the tray (belt conveyor) needed to be placed outside the tray. Also, to quickly retrieve items from the back of the shelf, I wanted the tray to move quickly without having to turn the knob many times. By creating a mechanism where a chain transmits the rotation of the knob to the gears inside the turntable, these two requirements were met

I used an already published chain for this mechanism (https://makerworld.com/models/1523122). Thank you

22 chain links are used. Do not use the original connectors published at the URL above. To ensure the chain connectors fit inside the turntable, please use the connectors on my plate

After assembly, a part of the chain is exposed and visible under the hand-rotated knob. This is because a space was needed to insert the chain during assembly of the turntable and also because the model needed to be scaled down to fit within the A1 mini build plate

Assembly Instructions

1. Assemble the chain. Use my model for the chain connectors to ensure the chain thickness does not change at the connector sections
2. Insert two small chain rings inside the chain
3. With the chain and chain rings combined, place them into the turntable's mainbody
4. Position the shaft of the large gear, which rotates the tray at the center of the turntable, so that it passes through the chain rings and its tip fits into the small hole in the mainbody. This will prevent the chain from coming out
5. Next, for the hand-rotated knob, ensure its shaft also passes through the chain rings and fits into the small hole at the bottom of the body
6. At this point, rotate the knob to confirm that the large gear rotates
7. If the gear rotation is fine, arrange the trays on top of the main body, and assembly is complete

Chain Assembly Instructions

1. Print a chain with a link length of 12.7mm from the URL above or similar sources. A total of 22 links are required

   The chain will have a lot of support material immediately after printing, so you will need to remove it as shown in the enlarged photos.

   　

2. Insert the white connector with two pins from the bottom side of the chain, and secure it with the holed connector from the top

   　

3. Install the assembly into the main body with the white connector facing downwards

   

Important Notes

　Although the length of one chain link is 12.7mm, the finished chain has some play (dimensional tolerance), so the distance between the two chain rings is a few millimeters longer than the theoretical length, taking into account measurement results from prototypes. However, depending on the filament actually used, it may be necessary to adjust the spacing between the chain rings

Enable supports when printing the turntable's mainbody and trays

I printed with PETG

Addendum

Since this model was also submitted to a contest, I wanted all parts to be 3D printable, so a 3D printed chain is used to transmit power to the turntable

Therefore, the thickness of the turntable body was determined to accommodate the chain. It is a bit thick, but the larger opening made it easier to remove print supports

After publishing this model, I learned that there are creators on MakerWorld who have published timing belts and timing pulleys. Timing belts require flexibility, so TPU filament is reportedly used, but I have no experience printing with TPU yet. If those timing belts were used, my model might have been made thinner

How to create extension parts of your desired length in Bambu Studio
As you may need longer extension parts, I will show you how to create extension parts of any desired length using the standard editing functions of Bambu Studio
Writing all the steps makes it long, but it's simple and can be done in about a minute once you get used to it. Please use it as a reference

1. Download and open the 3mf file
2. Click and select Extrabody on Plate3
3. Since you don't want to change the dimensions of the connector parts at both ends of the object, detach the connector parts at both ends before adjusting dimensions. Cut twice to split the object into three parts
4. Select <Cut> from the top menu bar
5. A rotation knob for the cutting plane will appear; rotate the green knob by 90 degrees to make the cutting plane vertical

6. Enter [-10] in <Movement> within the <Cut> menu to shift the cutting plane to the left. The value of Movement can be anything as long as the cutting plane does not overlap with the connectors at both ends of the object

   　

7. Check <Cut to parts> and click the <Perform cut> button
8. If you display Objects in the left Sidebar, it should be split into Extrabody_A and Extrabody_B
9. Select Extrabody on Plate3 again. After cutting in Step 8, it is already selected. Not the detached _A or _B
10. Select <Cut> from the top menu bar again
11. A rotation knob for the cutting plane will appear; rotate the green knob by 90 degrees to make the cutting plane vertical

12. Enter [10] in <Movement> within the <Cut> menu to shift the cutting plane to the right. The value of Movement can be anything as long as the cutting plane does not overlap with the connectors at both ends of the object

    　

13. Check <Cut to parts> and click the <Perform cut> button
14. The object is now split into three parts. When extending the part, move the connectors to their correct positions
15. Select the left part from the Sidebar and click the <Move> button in the top menu bar

16. In the numerical field for the X direction, enter the value with the desired dimension added. For example, if it contains [-20] and you want to increase the extension part by 60mm, enter [-80] to move it 60mm to the left. The size to extend the part should be a multiple of 30mm

    　　

17. Select the middle part in the Sidebar and click the <Move> button in the top menu bar to move it to the approximate center of the end parts. This movement does not need to be precise
18. Select the middle part and choose <Scale> from the top menu bar
19. Uncheck <uniform scale>

20. Drag the red points on the part to extend it. Extend it until it overlaps with the connectors at both ends. It doesn't need to be perfectly aligned; just ensure there are no gaps when overlapping

    　

21. Select all three parts in the Sidebar, right-click, choose <Merge into Single Part>, and combine them into one part

    

22. The merged object still shows overlapping lines, so remove them. Right-click the merged Object in the Sidebar and click <Fix model>

    

23. Done. Check the dimensions. In this example, an object that was 60mm long was extended by another 60mm, making it 120mm long. After that, slice it and confirm that there are no issues