The present invention relates to methods and apparatuses for fabricating an assembly which includes a blunt and, in one particular embodiment, relates to an apparatus for fabricating a needle assembly which includes a blunt.
The present invention relates to medical devices and other similar devices and in particular to medical devices such as intravenous catheters and syringes which include a hollow needle having a sharp distal end for piercing an object, such as the skin of a patient.
The existence of infectious diseases has highlighted the danger to which medical personnel may be exposed when treating patients by means of catheter devices and syringes where a sharp needle point is used to pierce the skin of the patient. In order to protect medical personnel against inadvertent needle stick, a number of solutions have been developed whereby a protective mechanism, incorporated within a catheter or syringe, prevents physical contact with the sharp needle point after use and hence protects against inadvertent needle stick. One such solution which has been developed is the use of a blunt which is contained within the cannula of the hollow needle. An example of a blunt is described in co-pending U.S. patent application Ser. No. 09/221,272, which was filed Dec. 23, 1998, by the inventors Joseph, Chang, Philip Schmidt, and Dennis Bialecki and which is entitled "Solid Blunt for a Needle Assembly." One example of a blunt described in this patent application is a blunt having a substantially D-shaped cross-section. In mass production, this blunt would typically be manufactured in large numbers before being inserted into the cannula of a needle in order to create the final product. Current manufacturing techniques for producing needle assemblies often include the use of a blade-style feeder which singulates a needle from a collection of needles in order to assemble the needle with the rest of the assembly which makes up the needle assembly. FIG. 1 shows an example of a process for singulating a needle from a collection of needles in order to fabricate a needle assembly by connecting the needle to a hub, etc. The feeder 101 is shown in FIG. 1 in cross-sectional view. The feeder includes a container 103 which has a wall 109 which supports a plurality of needles 107 such as needles 107a, 107b, 107c, and 107d. A blade-style feeder 105 is disposed within a slot 111 of the container 103. The blade 105 is coupled to a motor 112 which drives the blade up and down as shown by the arrow 114. When the blade 105 is driven down such that the top surface of the tip 105a is approximately at the position 105b as shown in FIG. 1, then one needle will tumble into the cutout of the tip 105a. As the blade 105 is pushed up away from the wall 109 to the position shown in FIG. 1, only one needle will remain in the tip 105a as any other needles will tumble off of the top of the tip 105a. This causes a single needle to be selected in a singulation process from the set of needles held in the container 103.
It is desirable in the manufacturing process for needle assemblies which include blunts to use a similar blade-style feeder to singulate a blunt from a set of blunts in order to take the singulated blunt and then insert it into the cannula of a needle to assemble the needle assembly. A D-shaped blunt presents a challenge for the blade-style feeder shown in FIG. 1. This challenge is shown in FIGS. 2A and 2B which show that the blade 105 may not successfully singulate one blunt from a collection of blunts. As shown in FIG. 2A, which is a cross-sectional view, two D-shaped blunts 203 and 205 may be stably maintained on the cutout of the tip 105a. In this case, it may be impossible to singulate one blunt from a group of blunts. Similarly, as shown in FIG. 2B which is a cross-sectional view, two blunts 207 and 209 may remain stably held in the cutout of the tip 105a when the blunts stack vertically as shown in FIG. 2B.
While it is desirable to use a feeder to singulate blunts in the same manner that a feeder is used to singulate needles, the currently existing blades do not provide adequate performance in singulating blunts.
From the above discussion, it can be seen that it is desirable to provide an improved method and apparatus for singulating a blunt in the process of fabricating a needle assembly or for fabricating other assemblies which use a blunt.