So I've been poking around this site where they specialize in such things as arm mounted fantacy weapons of all sorts...so I thought I'd try my hand at reverse engineering the Assassin's Creed 2 "xiphoid," as they refere to it, with what I've learned.
Here's my take on project based on what concept art the internet has yet been able to find...not much.
You may note that the pistol feature is missing..That part is a standalone unit that is worn over the blade unit but is not mechanically connected. It's an ingame uprade for later levels different from the one pictured in much of the character art. I have the pistol add-on internals detailed here at this [link]
Yay, the game has been released! Boo, I dont have a console or computer capable of playing it on. Yay for internet forum. New concept art proves this blade concept wrong asside from all the other flaws we found! You can find my updated version here at this [link]
The abstract is thus..
A ring pulls cord, cord is wound around a wheel, wheel is attached directly to a specialized cam (not drawn but there should be a coil spring to encourage counter clockwise rotation of the cam and wheel).
When pulled the cam rolls a push rod further into its slot extending a lazy tong. There is a relief cut into the rod to allow for an pin, anchored to the housing and to end of the lazy tong, to move.
The next intersection of the lazy tong is attached to the push rod directly, and a compression spring seperates the end of the slot and the push rod to allow the return of the unit to it's closed position once the cam is no longer forcing the push rod to the open position.
There is a lock lever that engages a notch in the cam after a certain pull length. Further pulling of the cam wheel will allow the lock lever to swing to a neutral point and, upon release of string tension and the cam wheels return rotation, will be knocked into an angle that will not engage the notch in the cam.
Attached to the end of the lazy tong would be the typical "Slide block sleeve/blade" unit from the official limited edition AC1 wrist knife.
Picture of that wall of text? See this [link]
Go check out
, he built a version of my drawing with a few improvements and omissions.