I acquired my Lucas from Phil Lucas in 2001.
The Lucas is 129 mm. tall, 48 mm. wide, 71 mm. thick, and weighs 305 g.
This is a noncommercial ascender with no markings.
Phil Lucas made this early homemade ascender In his words (pers. comm. 2001):
I made this ascender while working at the Newport News Ship Building and Dry Dock Company, Virginia in 1965. It is constructed from a split heavy wall pipe nipple and three-quarter inch steel plate for the cam. At the time I was unaware of any mechanical ascender and the design (such as it is) is entirely mine. Have you seen any other designs that squeeze the cam in this fashion? The foot or seat loop attachment is passed around the back of the ascender causing the cam to be pressed tightly against the rope. I tested the ascenders to ascend a 200-foot pit in Bull Cave, North Carolina. They worked just fine.
To answer Phil’s question, no, I haven't seen other designs like this one. This nice little ascender is the only one in my museum that works the way Phil describes, and I’m not aware of any others that copied this approach. The way the rope acts to close the cam is interesting. Naturally, this ascender was to be used as a substitute for a Prusik knot, since the more efficient mechanical rigs were yet to be invented.
To expand on Phil’s description, first remove the cam (carry a couple wrenches/spanners), place the ascender on rope, and replace the cam and bolt it in place. Next, pass your ¼-inch (6 mm.) manila (yes manila, you are living in 1965) sling through the triangular hole and bring one end around each side of the rope, then tie it into a loop. Clip the loop to the appropriate foot or seat sling. When ready to climb, loop the two sides of the sling over the corresponding spools attached to the cam. This way, the tension on the sling pulls the cam closed against the rope. The cam has no teeth, and will slip without the slings pulling it closed.
The steel construction makes this ascender rather heavy (but in the manila rope era, who cared?). Perhaps someone can work this idea into a lighter model and see if it has merit in today’s world!