I had designed a similar invention like the Patent
US5,934,963 but have found this patent was already in force.
It seems to have lapsed and been re-instated several times...
Can you determine the current status?
No, the patent has not expired. It was filed for in 1998 so it will probably be active through most of 2018.
Google Patents shows that it expired September 27, 2011 due to failure to pay a maintenance fee, but that a petition for late payment was granted.
Your best bet is likely to look into differentiating your invention, or licensing that patent.