An indwelling injector needle assembly having wings

Abstract: An indwelling injector needle assembly having wings, a cannula or needle body (11), a hub (12) supporting a proximal end of the needle body, a tubing (3) connected a proximal end of the hub, and a cylindrical holder (2) having a distal end from which the wings (4) protrude. The hub (12) can slide along an inner periphery of the holder, between a first position near the distal end and a second position near a proximal end of the holder. A latching mechanism is formed in and disposed between the hub (12) and the holder (2) so that the hub is inhibited from moving from the first position towards the second position, and vice versa, such that its injector needle is allowed to slide in order to retract the needle's pricking edge into the cylindrical holder, while leaving its wings retained on a patient's skin.

Description: The invention relates to an indwelling injector needle assembly having wings, said assembly comprising: a needle body in fluid communication with a tube; a hub disposed on and supporting said needle body, said hub having a guide groove extending longitudinally of said hub; a cylindrical holder disposed on said hub, said holder having wings protruding therefrom and a lug protruding inwardly from an inner peripheral surface of a proximal end thereof, said lug being slidably engaged with said guide groove in said hub so that said hub can be moved relative to said holder between a first position in which said needle body protrudes from a distal end of said holder and a second position in which said needle body is retracted so that a pricking edge of said needle body is within said holder; and a latching mechanism for inhibiting said hub from being displaced from said first position toward said second position, and vice versa. More particularly, the invention provides an injector needle held in a protector having the wings such that when the needle body slides into the protector after used, a needle edge is automatically retracted therein to protect a user from erroneously piercing his or her skin with the edge. Usually, the conventional medical needles are separable from protective members designed to accommodate the needles. Users of those medical needles have erroneously pricked often their fingers with the edges of used needles, when the latter were restored in the protectors held by their fingers. Thus, there is and has been a possibility that the users might be infected with the adventitious immunity defection syndrome (viz., AIDS) or hepatitis. Some injector assemblies have been proposed or provided to prevent such accidents. For example, US-A-5 120 320 discloses an injector assembly that comprises a protector integrally connected to an indwelling needle which has wing-shaped members. A used needle in this case is allowed to slide backward into the protector along a pair of guide slits formed longitudinally thereof so that the used needle's edge is hidden in the protector. In another assembly shown in JP-A-1-212561 on which the preamble of claim 1 is based, an indwelling needle is combined with a protector having wings. Due to a positioning mechanism intervening between the needle and the protector, the latter can forwardly slide toward the former so that a needle edge is enclosed not to injure the user. The wings integral with the needle body shown in US-A-5 120 320 are secured to a patient's skin, by means of an adhesive tape or the like. Such an indwelling needle cannot be retracted in situ into the protector, unless the tape is torn off and the needle is withdrawn from the patient's skin. Further, the needle body shown in JP-A-1-212561 often moves backward relative to the protector, due to a resistance of the skin being pricked with the needle. There is another problem that the needle body tends to slip off, when it is manually pulled backward to retract the needle edge into the protector. Therefore, an object of the present invention is to provide an indwelling injector needle assembly which comprises a needle body operable to slide back into a protector having wings so that a needle edge can be retained securely in the protector. Another object is to provide a needle assembly designed such that a needle edge can be retracted into a protector while its wings remain fixed to a patient's skin. According to the present invetion there is provided an indwelling injector needle assembly of the type mentioned in the beginning, which is characterized in that the hub comprises an auxiliary groove formed in a peripheral wall thereof, said groove being located side by side with said guide groove; said auxiliary groove having a distal end terminating at a distal end of said hub and a proximal end in communication with said guide groove. Thus, in accordance with the objects of the invention, the indwelling injector needle assembly having wings of the invention includes a needle body in fluid communication with a tube. A hub is disposed on and supports the needle body. The hub has a guide groove and an auxiliary groove formed in a peripheral wall thereof, the grooves being located side by side and extending longitudinally of the hub. The auxiliary groove has a distal end terminating at a distal end of the hub and a proximal end in communication with the guide groove. A cylindrical holder having wings protruding thereform is disposed on the hub. The holder has a lug protruding inwardly from an inner peripheral surface of a proximal end thereof. The lug is slidably engaged with the guide groove in the hub so that the hub can be moved relative to the holder between a first position in which the needle body protrudes from a distal end of the holder and a second position in which the needle body is retracted so that a pricking edge of the needle body is within the holder. The assembly also includes a latching mechanism for inhibiting the hub from being displaced from the first position toward the second position, and vice versa. The latching mechanism may include a first locking means for holding the hub at the first position, and a second locking means for holding the hub at the second position. It will be apparent from Fig. 3 and Fig. 4 and from the description given hereinafter that the first and second locking means are disposed at different angular positions around the axis of the hub. The members constituting the locking means will be detailed below. When a patient's skin is pricked with the needle edge, the needle body will be at its first position relative to the cylindrical holder. The latching mechanism is effective to retain the needle hub in this position securely lest the resistance of the skin being pricked will displace the hub towards the second position, that is towards its proximal end. After a medical treatment using this assembly is completed, the cannula (the needle body) will be retracted into the holder to take the second position in which the needle edge is hidden within the holder. The latching mechanism also serves to inhibit the hub from moving toward the first position, that is toward its distal end, unless forcibly urged. Further, the needle hub is also prevented from moving backward beyond its second position, so that the needle body will never slip off the holder. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of an injector needle assembly having wings, provided in an embodiment; Fig. 2 is a front elevation of the assembly shown in Fig. 1; Fig. 3 is a cross section taken along the line X - X in Fig. 1; Fig. 4 is a plan view of the assembly shown in Fig. 1 and partly in cross section, with a needle end of the assembly being retracted in a holder; Fig. 5 is a cross section taken along the line Y - Y in Fig. 4; Fig. 6 illustrates the first step of forming the assembly; Fig. 7 illustrates the succeeding step of forming said assembly; and Fig. 8 is a plan view of another assembly provided in another embodiment and shown partly in cross section. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to the drawings. As shown in Figs. 1 - 8, an injector needle assembly having wings provided in a first embodiment comprises a needle 1 having a tube 3 connected thereto, and a cylindrical holder 2 having the wings 4 integral therewith. The needle 1 is slidable within the holder 2 between a first position where the needle protrudes forward a distance from a distal end of the holder and a second position where the needle is retracted into the holder. A latching mechanism is provided in and between a hub 12 of the needle 1 and the holder, in a manner such that the needle is inhibited from being displaced from the first position toward the second position, or vice versa. A guide: groove 13 and an auxiliary groove 14 are formed in a peripheral wall of the hub 12, and located side by side and longitudinally of said hub. A distal end of the auxiliary groove 14 extends to and opens at a distal end of the holder 2, and a proximal end of the auxiliary groove communicates with the guide groove 13. A lug 21 is integral with an inner periphery of a proximal end of the holder 2. This lug 21 engages with and is slidable fore and aft in the guide groove 13. A cannula 11, i.e. the hollow main body of the injector needle 1, is made for example, of a metal such as stainless steel (preferably SUS-304) and has at its distal end a pricking edge. The proximal end of the cannula is connected to and held by a distal end of the hub 12. This hub 12, which has the guide groove 13 and the auxiliary groove 14 formed therein, is usually made of a flexible resin such as polypropylene, polyester or polyethylene. The distal end of the auxiliary groove 14 extends to and opens at the distal end of the holder 2, and the proximal end of the auxiliary groove communicates with the guide groove 13. The distal closed end of the guide groove 13 is formed as a recess 15, and this groove 13 extends thereform toward its proximal end. The recess 15 will engage with the lug 21 of the holder 2, when the needle 1 is retracted to the second position relative to the holder 2. A tube 3 is connected to the proximal end of the hub 12, which usually has two arms 16 disposed symmetrically and side by side. Alternatively, only one such arm may suffice. Each arm 16, which extends forwardly toward the distal end of the hub from a proximal end portion thereof so as to be disposed behind the guide groove 13, may be shaped as shown in Fig. 4. Hook 161 is integrally formed on a distal end of arm 16 and a slit 163 intervenes between each arm and a central columnar portion 162. Slits 163 allow the arms to flex easily and inwardly, because the hub 12 is made of a flexible material as described above. Each hook 161 has a generally U-shaped recess 164 as shown in Figs. 1 and 4. The hook is engageable with an aperture 22 and disengageable therefrom by flexing the arms 16 towards each other. Alternatively, each arm 16 may have a distal end having a spherically convex shape (as shown in Fig. 8) protruding outwardly of the hub so that a thin portion 165 is provided between the distal end and a proximal end of each arm. In this case, each hook 161 may readily be disengaged from a corresponding shallow recess 23 formed in the proximal end of the holder 2, by simply pulling the hub 12 away from the holder. The number of apertures 22 or recesses 23 is preferably the same as the number of arms 16. The auxiliary groove 14, useful when assembling this injector needle unit, extends to and opens forwardly at the distal end of the hub 12, lest the lug 21 formed at the proximal end of the cylindrical holder 2 should hinder the hub from being inserted therein. As a result of this feature, the lug 21 is allowed to slide along the auxiliary groove 14, until the hub is completely received in the holder 2. The lug 21 will then be transferred into the guide groove 13, because the latter communicates with the auxiliary groove. The first step of assembling this injector needle unit having wings is shown in Fig. 6. In this step, the lug 21 of the holder 2 will be caused to slide in and along the auxiliary groove 14 until bearing against the proximal end thereof so that the hub 12 is fully inserted in the holder, as will be apparent. In the next step, the holder 2 will then be rotated in the direction indicated at the arrow in Fig. 7. The lug 21 will thus transfer from the auxiliary groove 14 to the guide groove 13 communicating therewith through a transverse passage 17. Thereafter, the cylindrical holder 2 will be moved toward its proximal end so that its lug 21 now slides in the guide groove 13, until abutting the proximal end thereof and simultaneously causing each arm's hook 161 of the hub to fit in the corresponding aperture 22. The holder 2 is a cylindrical member for accommodating the hub 12, and the wings 4 integrally protruding sideways from the distal end portion of the holder are flexible. The hub 12 is slidable within the holder and along an inner periphery thereof, between the first position and the second position. As described above, the cannula will protrude a distance from the distal end of the holder 2 at the first position, whereas the cannula is retracted within the holder 2 at the second position. The lug 21 engageable with the recess 15 formed in the hub 12 protrudes inwardly from the inner periphery of the proximal end portion of the holder, as shown in Figs. 3 and 5 to 7. The lug 21 fitted in the guide groove 13 of the hub 12 is slidable only between the proximal and distal ends of the groove. Each aperture 22 engageable with the corresponding arm's hook 161 is formed through a portion of the peripheral wall of the holder, this portion being located nearer to the proximal end of the holder than the lug 21. In the case in which the hook 161 comprises a spherially convex end as shown in Fig. 8, the shallow recesses 23 may substitute for the apertures 22, at the same holder portions as the latter are located. The reference numerals 24 denotes a slit that facilitates the outward flexing of the holder portion where the lug 21 is formed. Such a slit will help this lug smoothly enter the auxiliary groove 14 and smoothly travel along the guide groove 13. In use, the hub 12 of the described needle assembly having wings will take an indwelling position relative to the holder 2 as shown in Fig. 1. This position is the first position described above, in which the cannula's distal end protrudes from the holder 2 and the arms 16 (viz. their hooks 161) are in engagement with the respective apertures 22 (or shallow recesses 23). Arms 16 and apertures 22 (or recesses 23) constitute the first latching means which prevents the hub 12 from moving relative to and towards the proximal end of the holder 2, when pricking the patient's skin with the needle end. After use, the user grips the arms 16 of the injector needle assembly shown in Fig. 1 with his or her fingers so that the arms flex inwards so as to be disengaged from the apertures 22. While gripping the arms the user will then move the hub 12 rearwardly towards its proximal end. The lug 21 of the cylindrical holder is displaced in this manner along the guide groove 13, from the first position to the second position, until engaging with the recess 15 located at the distal end of the groove. Thus, the lug 21 cooperates with the recess 15 to provide the second locking means for this injector needle assembly. The hub is thus locked at the second position where the pricking edge of cannula 11 is completely retracted within the holder. If the assembly is of a modified structure as shown in Fig. 8, then the arms 16 will likewise be gripped first. However, the simple backward pulling of the hub 12 will cause the hooks 161 to flex inwards so that the lug 21 disengages from the shallow recess 23. This motion will similarly be followed by the displacement of the lug from the first position to the second position in which the hub is locked by the lug 21 engaging with the recess 15 and the pricking edge of cannula 11 is completely retracted within the holder. It will now be apparent that the injector needle assembly having wings and provided herein is effective to protect those who are engaged in medical treatments and/or operations from erroneously pricking their skins with needle edges. It is further advantageous that the present assembly whose hub need only be displaced within the cylindrical holder toward the proximal end thereof to enclose the needle edge can be used more easily than the prior art assemblies whose wings have to be removed before removing the needle bodies.

Claims: An indwelling injector needle assembly having wings, said assembly comprising: a needle body (11) in fluid communication with a tube (3); a hub (12) disposed on and supporting said needle body (11), said hub (12) having a guide groove (13) formed in a peripheral wall thereof and extending longitudinally of said hub (12); a cylindrical holder (2) disposed on said hub (12), said holder (2) having wings (4) protruding therefrom and a lug (21) protruding inwardly from an inner peripheral surface of a proximal end thereof, said lug (21) being slidably engaged with said guide groove (13) in said hub (12) so that said hub (12) can be moved relative to said holder (2) between a first position in which said needle body (11) protrudes from a distal end of said holder (2) and a second position in which said needle body (11) is retracted so that a pricking edge of said needle body (11) is within said holder (2); and a latching mechanism (15, 21; 16, 22) for inhibiting said hub (12) from being displaced from said first position toward said second position, and vice versa; characterized in that the hub (12) comprises an auxiliary groove (14) extending longitudinally of said hub and formed in a peripheral wall thereof, said auxiliary groove (14) being located side by side with said guide groove (13); said auxiliary groove (14) having a distal end terminating at a distal end of said hub (12) and a proximal end in communication with said guide groove (13). The indwelling injector needle assembly of claim 1, characterized in that the latching mechanism (15, 21; 16, 22 or 16, 23) comprises a first locking means (16, 22 or 16, 23) for holding the hub (12) at the first position, and a second locking means (15,21) for holding the hub (12) at the second position. The indwelling injector needle assembly of claim 2, characterized in that the first locking means (16, 22) comprises at least one arm (16) and at least one aperture (22), said arm (16) being integral with the hub (12) and being disposed at a proximal side of the guide groove (13), said aperture (22) being formed through a peripheral wall of the holder (2) and being disposed at a proximal side of the lug (21), and that said arm (16) has a hook (161) for engaging said aperture (22) and integrally formed on a distal and outer end of said arm (16), said hook (161) being capable of being disengaged from said aperture (22) by flexing said arm (16). The indwelling injector needle assembly of claim 2, characterized in that the first locking means (16, 23) comprises at least one arm (16) and at least one shallow recess (23), said arm (16) being integral with the hub (12) and being disposed at a proximal side of the guide groove (13), said arm (16) having an outwardly protruding convex end (161) for engaging said shallow recess (23) and integrally formed on a distal and outer surface of said arm (16), said shallow recess (23) being formed in a peripheral wall of the holder (2) and being disposed at a proximal side of the lug (21) and that said convex end (161) is disengaged from said shallow recess (23) by pulling the hub (12) away from the holder (2). The indwelling injector needle assembly of claim 3 or 4, characterized in that the second locking means (15, 21) comprises the lug (21) of the holder (2) and a recess (15) formed in the guide groove (13) of the hub (12) at a distal end of the guide groove (13), the lug (21) engaging with said recess (15) when the hub (12) is moved from the first position to the second position.

Inventors: ARAKAWA KURANOSUKE, SHIMIZU KAZUHIRO, ARAKAWA, KURANOSUKE, SHIMIZU, KAZUHIRO
Applicants: NISSHO KK, NISSHO CORPORATION
Application year: 1995
Main classification: A61M25
IPC codes: A61M25, A61M5