Agree with Bob. Consider copying, compacting, zipping and posting your zipped db. From the pic, it seems a parent record is about a filter and the sub record is about a roller, so I doubt you can relate any sub records which appear to belong to Belts 2.
My advice would be to stop any development for what you have because there are design issues and you will always struggle if you stay the course. Spaces and special characters should be avoided in all object names, but that's not the reason for what your posted issue. You might want to review db normalization too.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.