How do I keep the huge hardwood floor in my restaurant clean without having servers labor for hours each night?

I currently work as the istant General Manager at a restaurant. The restaurant is in great condition, however, our dining room floor is clic hardwood. We seat about 60 people, and it is a pizzeria. This creates an extremely messy situation by the end of the night. Our servers generally sweep in the open areas of the dining room when they have the oppurtunity to. However, the corners of the dining room, and underneath the tables are extremely hard to get to. At the end of the night they have to move all of our heavy tables around the floor to try and sweep up the dirt. We are just using a simple broom and regular dustpan to do this. After the floor is sweeped, we mop the entire floor with murphy's oil. This process usually takes about 45 minutes to do well, and the next morning you can still find dirt crumbs everywhere no matter what. Is there a better strategy we should be using to keep this floor clean? Better equipment or a better process? PLEASE PLEASE HELP!