Stop the bobbin jumping out with a clear plastic plate which slides on over the Bobbin, whilst still being able to see if you are running out of thread.
Brother Innovis 10A/15/20LE/27SE/30/35/50/55FE/700/750E/900/950/955/1200/1250/1500/1500D/4000/4000D.
BC series. CS8000 series. AS40. JK4000. DS120/140. ES series. FS series.
NX200/NX400/NX600. XL2100/XL2200/XL2600 series. XR6600/XR7700 machines.