Needle Remover - Possible Designs

Possible Designs

The easiest needle-removers to operate are electrically powered, and either melt the needle or cut the needles at multiple sections. One patented design involves a syringe falling down into a chamber where powered moveable blades advance the syringe onto fixed blades on the opposite side, at which point the syringe is cut with a shearing motion at multiple points (Garvis and Beer, 1974). There are other patents that use electricity between electrodes or between rotating gears to short-circuit the needle and melt it off the syringe (Ch’ing-Lung, 1986; Hashimoto, 1990). A more complex design involves a hammer mill and grinder to break up and grind up the plastic and metal parts of the syringes, after which, the pieces are heated and cooled. The end result is metal particles encapsulated in a piece of plastic (Wallace et al., 1991).

However, electricity in developing countries is not a dependable source, so hand-powered needle-cutters would be preferred. Some designs use the squeezing force from a hand to force one or two blades to shear across each other and hence cut the needle between the blades (Choksi et al., 1981; Harner, 2004). There are other designs in which a twisting motion brings a shearing blade in contact with the needle and thus cuts it (W. Thead, D. Thead, and Evans, 2000). Another design has a stationary outer surface that the syringe body rests against and a cylindrical inner cutting body with a bore for the needle to pass through. A lever rotates the inner body, which shears the needle from the syringe and dumps the needle into a container (Johan and Morner, 1972). A crank system can be used to power a similar design, which also uses a cylindrical inner body. However instead of cutting the needle, the device pulls the needle completely out of the syringe, which deforms the needle, and dumps it into a container (Samuel, 2004). A more complicated design actually pulls the needle and collar from the barrel of the syringe without a rotational motion: the downward motion of putting the syringe into the device powers two arms to pull the needle off the syringe. The interesting aspect of this device is that it appears to be one-handed (Atsumi, 1996). Another one-handed device uses a downward motion to cause rotating gears to unscrew the needle and collar from the syringe (Thead and Evans, 1991). This design is very complex to implement, so an improvement of this design involves pegs that grip and rotate the needle collar instead of gears. The downward force is transferred into moving the pegs in helical slots, which causes the collar to rotate and the needle to be removed from the syringe (Han, 1994).

In 2006 a cheap and simple solution utilizing old cola or beer cans to dispose needles and specially developed lid to safely seal them has been developed. One click and the can is permanently sealed by the safely seal. The snap-lock seals the two parts together without using glue or tools. The ’collar’ of the cap is protecting the user during the needle separation process. The insertion hole is designed to separate needle and syringe at the point of use. No finger can pass through the opening. Each can securely contains 150-200 used needles (Business Ideas Forum, 2007).