Shouldn't we have continued access to the property for maintenance and security since our name is still on the deed?

Your name is still on the deed you have, but that does not mean you are still the owner of record. The usual procedure is that the property is offered at a foreclosure sale and the buyer receives and records a deed from the trustee. If no third party buys the property, the bank receives the trustee's deed and now owns the property. There could be dozens of deeds (including yours) in the chain of title, but only the latest one is effective. You should call a title company and ask them to prepare a title report for you. That is the only way you can know for sure who the current title holder (owner) is.

Even though you moved out of the house, it is still your house. It is customary for lenders to change locks etc so that house is protected as much as possible. This does not mean that you cannot go into your own property. Until the sale of the property occurs at the Courthouse when the foreclosure is competed or you sign a deed to the lender, the property remains yours. You could move back in if you wanted to do so. You should contact the lender to regain access to the house if you want to get into it for any reason. If the lender does not cooperate, you can go in with a locksmith and change the lock so you can get in. Be sure to confirm that you still have legal ownership of the property. You should contact an attorney who can check out the situation regarding the title and advise you of your rights at this time.

It sounds like the bank foreclosed on the house. If they did you can have no access to the property.

Most likely the bank changed the locks because you moved out. Each state has different laws and each contract is different governing this issue. You need to talk to a good foreclosure attorney in the state where the property is located.