When I was a senior in HS (1968) I worked for an aerial survey company as a photo lab technician. We had the largest copy camera in the world. But we also had a contact printer of the type you describe. I used it many times. The shipping lady that had been there since the 30s or 40s knew the contact printer inside and out. It was her favorite piece of equipment in the shop.
The printer had a glass on top (where one placed the print paper) and on top of that was mounted a flap of heavy canvas. Mounted to the heavy flap of canvas was about 10 heavy cast iron bars, similar to gold ingots in size ( about 30 lbs). This was to weigh the cover down over the print paper so the image could lay down on an even field. There was a rheostat for bulb intensity and the bulbs were mounted in a universal ball fixture so they could be moved in two dimentions, also the bulbs had the capability of moving up and down which made for a three dimentional way to move the bulbs. One would move the black neoprene curtain in front aside and manipulate the nine or ten bulbs height and location. And yes, I do remember the name of the unit...MacIntosh. A MacIntosh contact printer!