Compound bows (unlike recurve bows, their more mechanically-simple relatives) use a levering system with pulleys and spring tension to grant the user a mechanical advantage. We’re not exactly sure what to call [Zünder’s] bow design. He shared his unconventional take on a DIY bow that uses coiled springs as well as some other unique features.
What we really dig about [Zünder]’s design is how easy it is to grasp how it all works. As he demonstrates using the bow, the way the levers, pulleys, and spring tension all work together is very clear. The 3D-printed quiver and arrow rest are nice added touches, and we especially love the use of three toothbrush heads to provide contained support for a nocked arrow. The ring of bristles are sturdy enough to easily support the shaft, and don’t interfere with the arrow’s fletching.
[Zünder] has a photo gallery with a few additional photos and closeups, and you can watch him demonstrate his bow in the video embedded below.
We’ve seen some really clever DIY work when it comes to archery, like this effort at making a compound bow from PVC pipe, and this fascinating bicycle-wheel-based design that was built almost entirely from recycled and reused materials.
The history of the compound bow is quite interesting. It was invented in Rolla, Missouri, in the 1960’s. Manufacturers stole the idea and made bows to sell. The inventor had a tragic end.
That is all too common :(
Wikipedia has an article on the inventor https://en.wikipedia.org/wiki/Holless_Wilbur_Allen it says he patented the idea and it sounds like he was actually quite successful, what was the theft? Was it that his patent was too specific or something?
Hi Shannon,
As an independent, “micro-entity” inventor myself (I use uspto.gov’s e-File system), I can tell you what I’ve learned:
– Any inventor can write enough words and provide enough detail into a patent application to “differentiate it from prior art”;
– This makes it a PATENT; quite alright, but it DOESN’T guarantee that the patent is “DEFENDABLE” :-O
In order for a patent to be truly you have to walk a very fine line:
– the verbiage has to be SPECIFIC enough to DIFFERENTIATE it from all Prior Art; AND
– the verbiage has to be GENERAL enough to cover MYRIAD VARIATIONS on the design, so that anyone trying even the SLIGHTEST variation on the design is “infringing” on one or more of the patent’s “Claims” – aspects unique to the design.
As you surmised, the original inventor near-CERTAINLY “over-worded” his patent application, thereby GUARANTEEING that he’d be ISSUED a patent…
… while at the same time guaranteeing it would be TRIVIAL to “circumvent” that very same patent :-|
-Mark Vogt | VOGTLAND INNOVATIONS
As far as i can read, he was successful with his idea. He wanted a better bow and succeeded in building one, patenting his design and having a company selling it;
Allen patented his compound bow in 1969 (second image), and although there was a great deal of initial resistance (that first bow was rather ungainly), he finally found a bow manufacturer who was impressed enough to take on production, and by 1975, their company was selling all the bows they could produce, over 60,000 a year
source: https://www.lindahall.org/holless-wilbur-allen/
Patents are a two-sided sword, while they should protect intellectual property they shouldn’t hinder further innovations which clearly have new techniques of which the original inventor never thought. Check out the original picture of the compound bow compared to the “thing” in the article.
I would really like to see some sources for the claim that the inventor had a tragic end. I’ve had friends who was in the target and hunting archery communities in the 60s and the 70s and none of them have mentioned this to me.
Love it! Crossbow next please?
Thanks for featureing my bow here! For all those who like to see even more details, like the actual drawings, I have them on my website http://www.zuender.org under WORK > DIY Projects. Enjoy!
You embody the true DIY spirit, sir. Danke Schoene for sharing your design!
I noticed one possible issue.. it rotates as/after release. Prob not holding in/near center and that may require some adjusts to dimensions. Thanks for showing your work.
Sadly, according to Polish law this is classified as a crossbow. You can’t build it unless you’re a certified firearms manufacturer and you need firearms license to own it.
He needs to put some eccentric cams on there to allow a reduction of hold force while fully drawn. the 1:1 ratio he has on there now would be very tiring to use in a full day of shooting.
Can you tell me the dimensions of this springs please? I Need the lenght and the wire diameter