Most crossbows have some sort of cranking device available.I don't know the force needed but it is stated it is quite easy.I use a rope cocker.Those cut the draw weight in half.Works great for my Exocet 200.
Most of the cranking devices are only a few pounds pressure to crank. The rope cocker cuts the force in half. Almost all of the manufacturers have a cranking device available. Ten Point has one of the most user friendly and it will fit a few other bows as well.
Some crossbows, like the PSE Tac-15 must use a cranking device.
Yesterday, while cocking the bow, part of the plastic claw snapped off, rapidly loosing the bow string. Luckily, it was only at about 1/3 draw. Got a hold of TenPoint and, while they are sending me a new part, implied it was my fault. Maybe, maybe not.
For those of us who got into crossbows because we couldn't draw a compound bow anymore, a rope cocking device is still too much weight to pull. If you are shooting a 150 pound pull crossbow, you have to pull 75 pounds with the rope cocking device, and my right shoulder will not take that much strain. I absolutely need the crank cocking device, and it makes it easy to do the job, but it is slower and you need one more part (the crank) that you have to carry along and can misplace (I've done that).
My StrykeForce is 185# with 50% mechanical advantage that is 92.5 divided by two arms that is still 46.5 lbs. It's a pull. It's probably the only disadvantage to the SF that I've found having it for a year.
I don't understand how you can divide the force you need to apply by two arms. You are either pulling half the draw weight of your bow or you are not. You use two arms to pull it but that does not reduce the amount you are pulling. Let me use an example.
You have a large bag of feed to pick up. It weighs 100 pounds. You are a moose and can lift it with one hand, or you are like me and you need two hands to lift it, but it still weighs 100 pounds, not 50, doesn't it? Mechanical advantage is a wonderful thing, but it isn't magic.
When I finally figured out how to use the rope cocking device, I found the easiest was to lay the rope over the comb of the stock, let the hooks dangle down and latch onto the bow string. Then pull up with the handles. I'm not into physics, but I believe the comb acts as a lever or pulley, aiding in easier cocking. At least that's how I do it. Even though I have an Acudraw, I will always carry the rope device too.
You got it right Trader. Each pulley gives you 50% and there are two so each hand (if doing equal work) pulls a quarter (25%) of the total.
I have the latest Horton, It is simple and excellent. it comes with a small plastic piece that attaches by a screw to the rear of the box and keeps the cocking rope in perfect alignment. (Yep it adds 3/8 ounce to the heavy weight).
My first rope cocker was cast aluminum with brass pulleys, a good device. I used that so much I wore our two ropes and was on my third. By the way, I use parachute rope on my cocking devices, wears longer than most others.
The most common problem people don't appreciate is you SHOULD cut the cocking rope to fit your bow and you. The handles should be such that there is just a slight upward pressure on the bow-string without any pull. this means the cocking device is actually held in place before you begin to cock it. Once you do this, the all work great.
On the more powerful 225 lb Excaliburs, I shorten the pulley ropes so that I have to pull the string up about 3-4 inches to meet the hooks. They are a beast to get cocked if you don't. The higher you have to lift the handles the harder it is to get them cocked.