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Helge B.
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 Posted: Mon 05 May, 2008 6:13 am Post subject: Italian 16th century crossbow with internal crank |
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I found this replique in the internet. It supposes to ressemble a 16 century crossbow from Italy.
I find the internal cocking device very interesting though I cannot figure out how the crank will work. Any idea? What would be draw weight of this crossbow? Does anyone know where the original can be found?
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Leo Todeschini
Industry Professional
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Lin Robinson
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| Posted: Mon 05 May, 2008 12:29 pm Post subject: |
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| Leo Todeschini wrote: | The whole thing is a bit of a mystery to me - is it really supposed to be a replica of an existing one? I have never seen anything like it.
The crank must work by having a crown wheel on the crank handle and that turns a similar gear at 90 degrees on the end of a screw thread and the trigger/block/ catch/thing is mounted on a nut, so turn the handle and the thread at 90 degrees turns and the block is pulled back.
wierd
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It actually looks pretty simple but without disassembling the thing you cannot know for sure.
My guess is that the crank is attached to a gear and that the claw that pulls the bowstring back is attached to a worm gear. The claw probably has a hole in an extension on its rear end, which allows it to ride back on the shaft of the worm gear, pulling the string back as the crank is turned. Once the bow string reaches the catch, which is probably split in the middle, you crank the claw forward slightly, allowing the string to rest on the catch. The trigger is probably equipped with a spring which keeps it locked to the lower portion of the catch until you are ready to shoot. In order to release the bolt you squeeze the back of the trigger, which moves it down far enough to release the catch, sending the string forward and launching the bolt.
The catch would look like two semi-circles, one of which is of smaller diameter than the other. I would draw you a picture, but I am not where I can scan it to attach to the post. Maybe later this evening.
I have no clue about the original. As far as draw weight, a guess would be in excess of 100 lbs. Crossbows were made to be extremely powerful since they were drawn mechanically - in many instances - which meant the user did not have to be a big beefy guy to handle the weapon.
Lin Robinson
"The best thing in life is to crush your enemies, see them driven before you and hear the lamentation of their women." Conan the Barbarian, 1982
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Richard Hare
Location: Alberta, canada Joined: 15 Mar 2008
Posts: 135
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| Posted: Thu 08 May, 2008 6:44 am Post subject: |
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I suppose the mechanism could be compared to a rack and pinion by the looks of it.
I wonder if this type is shown in Sir R.P. Gallwey's book,"THE CROSSBOW?"
I'll have a look when I get a minute.
Would be interesting to try and make one sometime.
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Jean Thibodeau
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| Posted: Thu 08 May, 2008 8:54 pm Post subject: |
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| Richard Hare wrote: | I suppose the mechanism could be compared to a rack and pinion by the looks of it.
I wonder if this type is shown in Sir R.P. Gallwey's book,"THE CROSSBOW?"
I'll have a look when I get a minute.
Would be interesting to try and make one sometime. |
This one has a rotating crank but I wonder if one working like a car jack would work well ? Each stroke pulling the string on the crossbow a couple of inches until the string is captured by the firing mechanism?
Historical use of a car jack like mechanism ???
You can easily give up your freedom. You have to fight hard to get it back!
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This is a standard topic