AU724897B1 - Retractable needle for hypodermic syringes - Google Patents

Description

Australia Patents Act 1990 COMPLETE SPECIFICATIONS STANDARD PATENT Retractable needle for Hypodermic syringes The following statement is a full description of this invention, including the best method of performing it knowing to me Retractable needle for hypodermic syringes This invention relates to the development of a retractable needle that can be fitted to common disposable hypodermic syringes used world wide.

Every year many people contract infectious diseases by sharing needles or being prickled by used discarded ones.

There are several disposable syringes with retraceable needle in the market but the cost of them is too high to be handle by the needle exchange program here in Brisbane.

The above problems are overcome by the present invention, which provides a needle that can be used only once and eliminate the potential of accidental punctures.

All in an affordable price. (hopefully) Description and mode of operation of this invention retractable needle for hypodermic syringes.

Please note that along the description of this invention I will be making reference to: the needle with side arms, which forms one piece and the retractable device in which the needle is mounted. Both pieces combined together m1ade the retractable needle.

The retractable needle for hypodermic syringes, is a needle mounted in a sealed device made of hard plastic of cylindrical shape, of approximated similar diameter of the syringe that needs to fit, and several centimeters (approximately 3-6) high. (Or higher if required) Although one size of retractable needle would probably fit many different sizes of syringes, it could be easily customized to fit different sizes of syringes.

The retractable needle fits on top of the syringe, and allows the user to perform an injection as any needle but at the end of the injection it (the device) will retract the needle inside the device.

Mode of operation A modified needle (with side arms) is kept in injecting position by a mechanical locking mechanism. In the top section of the retractable device a loaded spring is set.

The bottom section of the needle is a little bit longer than the commonly used (non-retractable) needle. The end part of the needle is coming out of the retractable device and carefully must be inserted into the top hole of the syringe before injection. This operation is easily achieved since the diameter of the needle is much smaller than the diameter of the hole at the top of the syringe.

This extra length is necessary in order.of the retractable mechanism to be activated at the end of the injection.

Since the end of the needle is inside the syringe, to be able to inject the last remains of the liquid the plunger must be fully press. This action will push the needle upwards releasing the locking mechanism that until that moment was keeping the needle in injecting position. The loaded spring set at the top section of the retractable device will push the needle downwards, the locking mechanism that until that moment kept the needle in place would physically deactivate itself rending very difficult to re set the needle into injecting position. (to avoid the re-use of the needle) The side arms of the needle (and needle) will run downwards through a preset path. Near the end of this preset paths a set of inmobilisers will be over passed by the side arms, once over passed this inmobilisers will restrict the upwards movement of the needle i.e. the needle would be kept in the lower position even if the plunger is pressed.

Note: Since the length of the needle at the top of the retractable device (the sharp end used to pierce veins, skin or muscles) is shorter than the distance that the needle travels downwards, the tip of the needle will be kept permanently hidden inside the device. (Avoiding accidental punctures) Rubber septa are strategically placed in such a way that the liquid to be injected does not escape inside the retractable device The. end of the retractable device where the top of the syringe sets is designed with a very tight fitting in such a way that the action of pushing the needle upwards will NOT detach the device from the syringe.

On the sides of the needle, near the end of it, smaller holes are present. This is crucial because without this design once the plunger (normally made of rubber) pushes against the end of the needle, the needle would be sealed not allowing any more fluid to go through.

To assist with understanding the invention, reference will now be made to the accompanying drawing which shows the invention Note that a) drawings are not in proportion.

And b) it is very difficult for my to draw a three dimensional cylinder in two dimensions Fig I shows a needle with side arms needed for this invention Fig 2 shows the' "retractable needle" for hypodermic syringes armed and ready to be fitted on top of a hypodermic syriige for injection.

The needle 1 and its side arms 14 are kept in injecting position by the loaded spring 2, locking mechanism 3 and base 4. the "base" is made by the body of the retracting mechanism (hard plastic) more details of this section can be seen in fig4 and The preset paths 5 that are used as a "guide" for the side arms of the needle 14 are also made by the body of the retractable mechanism.

Near the end of the preset paths 5 the set of inmobilizers 6 are present this inmobilizers could be made of strips of metal or strips of plastic and it function is not to allow the needle to go upwards ones the needle is retracted after being used) Small holes 7 are present at the end of the needle to allow the liquid to go through, once the plunger of the syringe is pushing the needle up and sealing the end of the needle.

Rubber/s septums 8 are fixed in the body of the retractable device making a seal between the needle and the device this is necessary in order to avoid the liquid to be injected escaping inside the device.

A tight fitting 9 is present at. the bottom of the retractable device. Here is where the top tip of the syringe and the device make contact. This fitting must be quite tight in order for the device not to be dislodged from the syringe at the end of the injection once the plunger pushes the needle upwards.

Fig 3 shows the retractable needlelafter injection (retracted). The spring 2 relaxed the locking device 3 in locking position (more details of locking device are present in fig 4 and fig the inmobilizers 6 trapping the side arms of the syringe.

Fig 4 shows a detail of the side arm of the needle 14 resting at the base 4 in injecting position, the locking mechanism 3 have three important fiunctions. Its first finction is to deactivate the base after injection by blocking it in such a way that after injection the side arm cannot rest again in the base making it fall in the preset path 5. The second fiunction is to push the side arm against the base making more difficult a miss fire by shock (i.e the device is dropped) and third, once the needle is pushed upwards by the plunger the locking mechanism will push the side arms dislodging it from the base.

Note: there are two bases 4, two locking devices 3 and two side arms 14 in a retractable needle each one of this are set opposite to one another in each side of the body of the device, in such a way that once the plunger pushes the needle upwards the locking devices will push the side arms of the needle making the needle and side arms to rotate (just a fraction in an anti clock wise manner.

It is only necessary to rotate the side arms of the needle 14 just a fraction, since once the pressure in the plunger is released the loaded spring 2 will push the needle I downwards making the side arms 14 to slide out of the base 4 in to the pre set paths shows the base 4 deactivated by the locking mechanism 3 and the side arm 14 down the pre set path Page(s) were not lodged With this application

Claims (4)

1. a retractable needle compressing a needle with one sharp end, side arms, final and lateral holes, mounted in a device with a loaded spring, base in which the side arms of the needle sets, locking mechanism which maintains the needle in injecting position and helps the needle to be displace from the base and deactivates the base after retraction of the needle, in such a way that the needle cannot be re-used, the device has also preset paths on which the side arms slide downwards and inmobilizers that. traps the side arms in a low position keeping the needle tip inside the device even if the end of the needle is pushed upwards and the device has a tight fitting at the end of it in which the tip of a syringe is inserted.

2. The retractable needle of claim 1 wherein the end of the needle is rounded (bubble like) with final and side holes, which would make accidental punctures much more difficult in case that the device of claim one is separated from the syringe after retraction.

3. The retractable needle of claim land/or 2 wherein a tight fitting in which the tip of a syringe is inserted with trapping blades or metallic whiskers which do not allows the separation of the device from the syringe once mounted.

4. The retractable needle of claim 1 to 3 made out of different materials other than hard plastic, different, shapes, colors and sizes to fit different syringe sizes. X [ORABI TO March i, 2000