One of the major problems with hyperdermic needles is that they can be used multiple times. This is devestating to 3rd world countries where needles are amazingly used more than once two inject life saving drugs and vaccines.
This use-once needle has a simple locking mechanism that makes it unusable after being used once. Forcing it open will break the vacuum form causing it to be worthless.
The lock mechanism a series of plastic one way teeth designed to break the entire tube if forced open.-- SpocksEyebrow, Jun 05 2005 Not a new idea http://www.aegis.co.../1998/AD981654.htmlSome reasons why they're not as good an idea as you might think. [DrCurry, Jun 05 2005] Single Use Needle http://www.smartsyringe.com/This is the thing that I'm familiar with. [zigness, Mar 13 2006] Doesn't this mean that the needles must be pre-loaded with whatever you're using them for?-- Detly, Jun 05 2005 <pedant mode> sp: once to inject </p>.
Sorry don't know what came over me there. I like th concept of this idea but, try as I might, I cannot seem to visualise it.-- hidden truths, Jun 05 2005 There are dozens of patents on one-use hypos, and there are many of them on the market (eg, the plunger grabs the needle and pulls it into the barrel on the backstroke, or jams something into it, or else the needle has a polymer coating inside that swells irreversibly after use), but I don't understand how this particular one works from the description.-- ldischler, Jun 05 2005 This person cannot spell for sour toffee. Nor describe.
What I think is intended is a bit like those plastic wire ties/tie wraps. A "series of plastic one way teeth" that go click, click, click as the plunger is depressed, and that keep the plunger from being pulled back out. Although where in a syringe this is supposed to fit, I can't guess. If it's inside the barrel the plunger is going to leak, if it's anywhere else it can be meddled with.
As [Detly] points out, this means an empty syringe cannot be filled--it has be be filled at the factory or shipped in two pieces and assembled after filling. The mechanism could be designed to allow one withdrawal of the plunger--for the initial filling from standard bottles--but that's not in the description and would add to the complexity of the syringe.
All this is going to cost money, and money and the lack thereof is the reason that third-world doctors are re-using needles in the first place. To expect people to pay more money for less use is not logical.-- baconbrain, Jun 05 2005 Hmm, a needle with an excess of a particular layer of skin? How would that help?-- half, Jun 05 2005 Baked. Not as complex as all this. Pull back on the knuckle cleats with the plunger depressed and the barrel slides forward and locks into place -- beyond the needle bevel and integrated with the syringe body. Pretty sweet.
I always wonder about the altruism of laymen ... all that concern with germs and sterility; seems a bit like regression to the Middle Ages.-- reensure, Jun 05 2005 This is basically a very sound idea [+] that hasn't been thought through [-].-- wagster, Jun 05 2005 Hypodemic nerdle. [-]-- Basepair, Jun 05 2005 [marked–for-deletion], commonly known to exist.-- zigness, Mar 12 2006 I didn't know this existed. Is this really that commonly known?-- jutta, Mar 12 2006 Among the medical community (which is pretty big)... my brother uses needles like this for insulin. I'll look for a link.-- zigness, Mar 13 2006 <later> I posted a link. <l>-- zigness, Mar 13 2006 Existing is one thing. But this has gone 9 months without anybody picking up on that. I wouldn't have called it widely known.-- hidden truths, Mar 13 2006 I'd certainly call it widely known... just not widely read on the HB...-- zigness, Mar 13 2006 random, halfbakery