Greetings from the Catskill Mountains of NY State !
You have a winch of a type known as a "crab" winch. It was made by a number of manufacturers in the USA. It is/was most commonly used for temporary hoisting of light loads on construction projects. I cannot tell you a load rating. The size of the wire rope can give some idea, but should NOT be taken as the load rating. Heavier rope than the winch was rated for may have been spooled onto it. My guess is the winch capacity is somewhere around 1 ton to 1 1/2 tons.
This type of winch was still manufactured in the early 2000's when I bought two of them for a specialized job on a hydroelectric powerplant. We were using the winches to drag loads along the length of a long, sloping penstock (large pipe which delivers water to the turbines).
Another common application of this type of winch was on hand-operated derricks or cranes. The type of winch was and is quite common, and it was used in a wide variety of applications, wherever a load had to be pulled or lifted. In places where power was unavailable, or use was not so frequent, or where more length of wire rope than an electric hoist would have was needed, these winches found use. Some were fitted with large handwheels and used on small tugboats and barges to pull the barges and tugs together.
I am sorry that I cannot give you any idea of year of manufacture, nor can I give you any idea of value. The fact the wire rope looks un-rusted and only light rust on the gears tells me the winch is in fairly good condition, and probably was in use or at least stored indoors (or under cover) until recently. In the USA, at a sale of equipment, I would guess the winch might go for anywhere from a few dollars to maybe $100.00-$150.00. The kicker in this is called OSHA. Nowadays in the USA, any equipment made for lifting has to have a load rating on it and be tested and certified for that rating. Not sure if this type of winch with manual ratchet and manual band brake is allowed for use in the USA for lifting overhead loads anymore. I would not call the winch an antique or anything rare, maybe because I saw them in use in my career. It's a handy winch if you have some use for it.
