Abstract:
Protection for the otherwise exposed sharp point of a needle of an injection device. A two part cover for the needle comprises a stationary base which engages the injection device, and a relatively movable cover. The cover is guided to slide longitudinally along the base by a groove-and-projection system. The projection is held in an initial position, and slides along the groove during injection. At the end of the injection, the projection is immobilized in the groove at a final position, and immobilizes the moveable cover in a deployed position covering the needle.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention pertains to injection devices such as syringes and autoinjectors, and more particularly to a guard arrangement which covers sharp points of injection devices. 
       BACKGROUND OF THE INVENTION 
       [0002]    Syringes, autoinjectors, and like injection devices have long been used to deliver medicaments and other substances transdermally. An injection device typically has a reservoir for storing a liquid to be injected, a plunger to pressurize the stored liquid, and an elongated slender pointed needle for penetrating skin and other tissues, so as to deliver the pressurized liquid into the body. 
         [0003]    Because the point is very sharp, it easily penetrates human tissues, clothing, protective gear such as rubber gloves, and other articles. This presents a hazard to medical personnel due to unintended pricking of the personnel&#39;s body. This can be uncomfortable, can cause the personnel to drop or otherwise mishandle equipment, and most of all, threatens to transfer contaminants from an injected person&#39;s blood to the medical personnel. 
         [0004]    Countermeasures directed to unintended pricking of the body have been proposed. However, many countermeasures introduce annoying drawbacks. For example, a cover may need to be manually installed and manually removed when needed. This may for example oblige medical personnel to put down other equipment and objects and perform the necessary installation or removal, or otherwise interfere with expeditious performance of medical tasks. 
         [0005]    There remains a need for an uncomplicated yet effective protective device for preventing unintended pricking due to exposed needles, or “sharps”, as they have become informally known, which is self-deploying and which makes minimal demands on 
       SUMMARY 
       [0006]    The present invention addresses the above concern by providing a self-deploying cover assembly for exposed needles and the like. The self-deploying cover or protective guard may be a self-contained device which is installable to the needle assembly of an injection device such as a syringe or autoinjector having a separately installable needle assembly. 
         [0007]    The overall function of the guide structure is to immobilize the injection device in an initial or “ready” position, and to subsequently lock a protective sleeve or cover over the needle at the conclusion of the injection. The structure of the protective guard may include two complementing parts, one of which is secured to the injector device and may be regarded as being stationary relative to the injector device, the other part being movable relative to the stationary part. The operative principle includes a guide structure, for example comprising a guiding groove formed in a first part, and a projection which is formed in a relatively movable second part, and which rides within the groove. The guide structure may be formed in one of the first and second parts, and the projection may be formed in the other of the first and second parts. As the injection proceeds, the projection rides in the groove as the first and second parts move relative to one another. 
         [0008]    The groove is configured to include a first receptacle which holds the projection until manual force moves the second part such that the projection forces its way out of the first receptacle. Travel of the second part and its projection towards the patient being injected brings the projection to a point enabling maximal projection of the needle from the injection device. When the injection is finished, the needle may be retracted, with the second part of the self-deploying cover following passively as the needle retracts, but latching into a final position which latches the protective sleeve over the needle point so that direct access to the needle point is prevented. 
         [0009]    A spring provides force to move the second part as described. Movement of the second part relative to the first under influence of this spring causes the protective device to be self-deploying in that once installed, the user need take no affirmative action to assure that the protective sleeve be moved to a deployed position covering the needle point at the conclusion of injecting. 
         [0010]    A supplementary cover which surrounds the second part and covers the exterior surface of the second part is preferably provided. The supplementary cover may provide an outwardly projecting flange for providing convenient support for the fingers of the person administering the injection. 
         [0011]    A significant advantage of the present invention is that the novel self-deploying protective cover enables medicaments to be provided with needle assemblies which may then be installed in the barrel of the syringe. The syringe and its associated plunger may be reused, which limits the structure which must be renewed after each injection to the needle assembly and its associated fluid reservoir. Alternatively stated, it is not necessary to utilize and discard an entire injection device after each injection. The injection device which may enjoy the benefits of replacement of needle assembly only is protected against inadvertent pricks by the novel self-deploying protective cover. 
         [0012]    The novel self-deploying protective cover may be made available as a modular adjunct or accessory to the injection device, so that not only are the barrel and plunger of the injection device retained for subsequent usages, but so is the self-deploying protective cover. 
         [0013]    It is an object of the invention to provide improved elements and arrangements thereof by apparatus for the purposes described which is inexpensive, dependable, and fully effective in accomplishing its intended purposes. 
         [0014]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0016]      FIG. 1  is an exploded side view of elements of the self-deploying protective cover of the present invention. 
           [0017]      FIG. 2  is a side view of the components of  FIG. 1  shown assembled. 
           [0018]      FIG. 3  is a side view of the components of  FIG. 1  assembled over an injection device, showing the plunger of the injection device as it would be immediately prior to an injection. 
           [0019]      FIG. 4  is a side view similar to  FIG. 3 , but showing the plunger mostly but not fully depressed. 
           [0020]      FIG. 5  is a side view similar to  FIG. 4 , but showing the plunger fully depressed. 
           [0021]      FIG. 6  is a side view similar to  FIG. 5 , but showing the needle retracted into the protective cover, the point no longer exposed. 
           [0022]      FIG. 7  is a side view similar to  FIG. 6 , but showing the protective cover latched into the deployed position covering the retracted needle. 
           [0023]      FIG. 8  is a partly cross sectional side detail view of a component seen at the left of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Referring first to  FIG. 1 , according to at least one aspect of the invention there is shown components of a self-deploying protective cover  10 , without its associated injection device  12  (which will be seen in  FIG. 3 ). The self-deploying cover  10  may comprise a base  12 , a protective sleeve  14 , and a coil spring  16 . The protective sleeve  14  may have an open interior  18  adapted to interfit telescopingly with the base  12 . That is, the open interior  18  may be dimensioned and configured to slidably receive the base  12  in close cooperation therewith. 
         [0025]    The base  12  is seen to have a finger  22  bearing a projection  24 . The finger  22  is defined by a U-shaped channel  26  formed in the wall  28  of the base  12 . The projection  24  projects outwardly from the finger  22 . Projection in the outward direction will be understood to be away from the axis  30  of the protective sleeve  14 . The axis  30  is coincident with the longitudinal axis of the needle of the injection device (see  FIG. 3 ). For example, if formed as part of a self-deploying protective cover which is fabricated to scale for use with a typical syringe or autoinjector, such as the syringe shown in  FIG. 3 , the projection  24  may rise above the surrounding surfaces by a magnitude of perhaps one thirty-second or one sixteenth of an inch. 
         [0026]    Of course, in other implementations of the invention, a protective sleeve corresponding to the protective sleeve  14  may be received within a base corresponding to the base  12 . 
         [0027]    Turning momentarily to  FIG. 8 , the protective sleeve  14  may have an internal shoulder  20  adapted to generate a seat or reaction surface for the spring  16 . The base  12  may have a corresponding shoulder (not shown, but similar in construction to the shoulder  20 ) so that the spring  16  may urge the base  12  away from the protective sleeve  14 . 
         [0028]      FIG. 2  shows the components of  FIG. 1  united or assembled. Also, a new component is introduced in  FIG. 2 , namely, an outer sleeve  32  which is disposed to slip over the protective sleeve  14  along part of the length thereof. The outer sleeve  32  may have an outwardly projecting flange  34  for engaging the finger or fingers of a user when the user is grasping an injection device to be used with the self-deploying cover  10 . For the purposes of this invention, the term “finger” may encompass the thumb. 
         [0029]    The protective sleeve  14  may comprise an external circumferential shoulder  36  (best seen in  FIG. 1 ) disposed to limit axial travel of the outer sleeve  32  along the protective sleeve  14 . As seen in  FIG. 2 , the outer surface  38  of the outer sleeve  32  may be coextensive with the outer surface portion  40  of the protective sleeve  14 , so when the protective sleeve  14  and the outer sleeve  32  are assembled, the respective outer surfaces  38 ,  40  are flush. 
         [0030]    The self-deploying protective cover  10  has a guide feature to facilitate moving the protective sleeve  14  between a deployed position covering the needle of the injection device (as seen in  FIG. 7 ) and a retracted position exposing the needle for administering injections (as seen in  FIG. 3 ). 
         [0031]    Again referring to  FIG. 1 , the protective sleeve  14  comprises a groove  42  of somewhat complex configuration, which serves primarily to define a path of travel of the projection  24  as the protective sleeve  14  moves between the retracted position of  FIG. 3 , which exposes the needle  44 , and the deployed position of  FIG. 7 . These motions are in directions parallel to and in coaxial relation to the longitudinal axis  30 . 
         [0032]    The groove  42  comprises a principal channel  46  which is occupied by the projection  24  throughout most of the motion of the projection  24  during operation of the self-deploying cover  10 . Other channels formed in the groove  42  generally provide lesser support functions other than guiding the projection  24  along the longitudinal axis  30 . The lesser structural features of the groove  42  will be described hereinafter. 
         [0033]    During motion of the projection  24  and hence between the base  12  and the protective cover  14 , and also referring to  FIG. 3 , the base  12  engages an injection device such as a syringe  48  having a needle assembly including the needle  44 , a barrel (of which only a flange  50  is visible), and a plunger  52 . The plunger  52  is adapted to fit into and slidably along the barrel so as to engage and impose pressure on the removable needle assembly, thereby driving fluid to be injected through the needle  44  as injection proceeds. The needle assembly may be conventional, and is used with some syringes so that needle assemblies only need be renewed, the barrel  50  and plunger  52  being reusable. In the assembled condition shown in  FIG. 3 , the base  12  engages the barrel of the syringe  48 , thus providing a stable platform relative to which the protective sleeve  14  may move. Interaction of the projection  24  and the groove  42  causes the base  12  to guide the protective sleeve  14  as the protective sleeve  14  moves between the deployed position and the retracted position. 
         [0034]    Engagement of the barrel by the base  12  is improved by an engagement element  72  which is disposed to engage and retain the outwardly projecting flange  50  of the barrel of the syringe  48 . The engagement element resiliently fits to and partially surrounds the flange  50 . 
         [0035]    The principal channel  46  is dimensioned and configured to receive the projection  24  in close cooperation therewith. The principal channel  46  may have an initial terminal  54  located proximate the point  56  of the needle  44  and a final terminal  58  located proximate the plunger  52 . The principal channel  46  is parallel to the longitudinal axis  30 . 
         [0036]    A deflectable arm  60  is formed in the groove  46 , being defined between the principal channel  46  and a relief channel  62 , the entire purpose of which is to contribute to defining the deflectable arm  60 . The deflectable arm  60  terminates in an enlarged head  64  which is configured to restrict the open area of the principal channel  46 . Ordinarily, the enlarged head  64  obstructs the principal channel  46  to casual or unintended travel of the projection  24 . However, under manual pressure imposed by depressing the plunger  52  as for an injection, the deflectable arm  60  deflects by moving laterally by the projection  24 , thereby enabling the projection  24  to move along the principal channel  46  towards the final terminal  58 . It may be said then that the enlarged head  58  of the deflectable arm  60  yieldingly closes the principal channel  46 . This creates a one-way gate which immobilizes the projection  24  and hence the protective sleeve  14  in the deployed position covering the point  56  of the needle  44 , as will be further described hereinafter. 
         [0037]    Returning to  FIG. 2 , the initial position of the self-deploying cover  10  on the syringe  48  is shown. The groove  42  is seen to comprise a retention element which communicates to the principal channel  46  and is disposed to retain the projection  24  in the retracted position immediately prior to commencing an injection. The retention element is disposed between the initial terminal  54  and the final terminal  58 , and more particularly is located proximate the initial terminal  54 . In the retracted position seen in  FIG. 3 , the needle  44  and its point  56  are exposed and may be inserted into the patient. 
         [0038]    The retention element comprises a short deflectable retention arm  66  which retains the projection  24  in a short retention channel  68 . Once the plunger  52  is fully depressed and the shot has been administered, the continued pressure on the plunger  52  affects the barrel and base  12  assembly, and more specifically the projection  24  to ride in a cam-like manner on the surface formed in the short arm  66 , and after being released from engagement with the short arm  66 , responsively moves circumferentially to the principal channel  46 . From this point, and responsively to the further depression of the plunger  52  (and the further compression of the spring  16 ), the projection  24  moves first towards the initial terminal  54  and subsequently towards the final terminal  58 . Frictional characteristics of the interfit of the base  12 , the protective sleeve  14 , the barrel of the syringe  48 , and the needle assembly bearing the needle  44 , and spring characteristics of the spring  16 , which is disposed to urge the protective sleeve  16  into the deployed position relative to the base  12 , assure that the protective sleeve  14  will move relative to the base  12  as described. The needle assembly may be a conventional needle assembly which is separate from the rest of the syringe  48 . 
         [0039]    After the movement of the plunger  52  and barrel assembly (illustrated in  FIG. 4 ) is sufficient to dislodge the projection  24  from the short channel  68 , by displacing the short arm  66  as shown in  FIG. 5 , continued depression of the plunger  52  will ultimately force the projection  24  to occupy the initial terminal  54 . The needle  44  may be projected additionally by such continued depression, as indicated by a dimension arrow  70  in  FIG. 5 . 
         [0040]    Turning now to  FIG. 6 , release of pressure on the plunger  52  will enable the spring  16  (not visible in  FIG. 6 ) to urge the base  12  apart from the protective sleeve  14 . This causes the base  12  and barrel assembly (along with the plunger  52  contained within the barrel) to move to the right as seen in  FIG. 6 , thereby retracting the needle  44  attached to said barrel, which is no longer visible in  FIG. 6  because it has retracted into the protective sleeve  14 . 
         [0041]    It will be seen that as the projection  24  rides within the principal channel  46  from the initial terminal  54  of the principal channel  46  to approach the final terminal  58 , it passes the enlarged head  64  of the deflectable arm  60 , thereby causing the deflectable arm  60  to deflect. Deflection allows the projection  24  to pass the enlarged head  64 . The deflectable arm  60  then returns to its normal position, as shown in  FIG. 5  for example. As best seen in  FIG. 7 , return of the deflectable arm  60  opposes return of the projection  24  in an opposite direction after passing the deflectable arm  60 , thereby entrapping the projection  24  at the final terminal  58  of the principal channel  46 . The projection  24  and hence the protective sleeve are thus secured in the deployed position. 
         [0042]    In one implementation, the invention may be regarded as a self-deploying protective cover such as that utilizing the protective sleeve  10 , the base  12 , and the spring  16 . Optionally, the invention may be regarded as a self-protective cover of the type described above, further comprising the outer sleeve  32 . 
         [0043]    In another implementation, the invention may be regarded as an injection device such as the syringe  48 , improved by further comprising a self-deploying protective cover for covering the sharp point of the needle of the injection device. 
         [0044]    The present invention is susceptible to modifications and variations which may be introduced thereto without departing from the inventive concepts. For example, action of deflectable members such as the deflectable arms and may be modified such that the displacement occurs in a radial direction relative to the axis of the needle of the injection device, such as the needle. Where such modification is practiced, elements such as the supplementary cover may be modified to accommodate outward deflection while still performing their intended functions. Also, relative locations of the groove and the projection may be exchanged between the protective cover and the base if desired. 
         [0045]    While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is to be understood that the present invention is not to be limited to the disclosed arrangements, but is intended to cover various arrangements which are included within the spirit and scope of the broadest possible interpretation of the appended claims so as to encompass all modifications and equivalent arrangements which are possible.