Pump action crossbow (powerful)

I would love to know if a pump action crossbow exists that has reasonable power, most designs iv seen are weak due to the pump action system, but i was wondering if anyone has managed to make a powerful one maybe using cogs/gears to torque up the power.  

thanks for having a look at my post please don't hesitate to respond.

Years ago, I knew a guy named Floyd Stevens (Stephens?) who live in a suburb of Austin Texas.  He built a magazine fed repeating crossbow that was spanned with a pull strap.  He made both a pistol and a carbine, and the carbine showed up in low-budget action movie filmed in the Philippines.  The stock would accomodate a number of different weight prods, from a minimum of @ 75 lb, thru approx 150.  Needless to say, the light prod was used in the movie.  I know Floyd actually patented his mechanism... so it's available for perusal from the US Patent Office. It's my impression Floyd eventually sold the patent to a commercial manufacturer.  I haven heard from Floyd for 20 years, and have no idea how to get in touch, still an online search for Floyd Stephens or Floyd Stevens crossbow might bring something up.  Geezer

I just checked online: Floyd Stephens patented his crossbow system in 1987.  I have some photos of his pistol-model repeater somewhere on my computer.  I'll try to find them again.  If so, I'll post a notice. Geezer.

Okay, for what it's worth, I have located my photos of Floyd Stephens' repeating crossbow pistol, with 5 shot internal magazine.  There's not a lot of detail in these photos, but if you can find the Patent Office sketches, the photos may be of some use.  Those who want the pics, drop me an e mail at : iolo@crossbows.net   I'll send you the files.  Geezer.

Hello, Ivanhoe: Pics on the way.

I think you'll find the relevant patent drawings here: https://patents.google.com/patent/US4662345A/en

Yes, that's Floyd Stephens' repeater.  Actually I saw two examples, the pistol and a longer, stocked model.  Both were crafted almost entirely of aluminum, and his work was very clean.  Except for a few oddly placed screws, you might have thought they were production models.  As I said earlier, at least one of these bows was used in an action/adventure movie filmed in the Philippines, about the same time as the patent was issued.  Floyd had replaced the spanning-handle with a soft fabric strap, so the actor could span the bow with his teeth (yeah, really) Needles to say, for the film, they used a light, 75 lb. prod.  His stronger, carbine model was fitted with a 125 or 150 lb. Barnett prod... I don't recall which.  Anyhow, the machine was quite workable.  The only drawback I saw was the very short darts... those would certainly disappear into a target and have to be dug out.  Anybody else who needs photos, drop me an e mail.  Geezer.    iolo@crossbows.net

@Geezer, thanks for the images man its a work of art and for some reason i never considered a pulley system, in my head i always saw a gear / series of cogs system to ease up the load on the wielder. Some tweaking could actually turn this design into a pump action.

@PierreC, thanks for the patent link ! Will help in the project if i ever get it off the ground.