DE20006251U1 - Needle guard assembly - Google Patents

Description

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B D Medico GmbH

M7219GM/IT1

04.04.2000

Needle protection arrangement The invention relates to a needle protection arrangement for an injection needle.

Because of the risk of injury or infection from a used injection needle, there is an increasing requirement that the needle be covered by a protective device after an injection in order to minimize or eliminate this risk.

It is therefore an object of the invention to provide a new needle protection arrangement which reduces such risks.

According to the invention, this object is achieved by the subject matter of claim 1. By means of the movable cam element, in cooperation with the cam curve, it is achieved that the needle protection cap comes into a blocking position after an injection, i.e. after the needle has been pulled out, in which the needle protection cap encloses the needle and prevents injury or infection caused by the needle.

Further details and advantageous developments of the invention emerge from the exemplary embodiments described below and shown in the drawing, which are in no way to be understood as a limitation of the invention, as well as from the dependent claims. It shows:

Fig. 1 is a schematic longitudinal section through a first preferred embodiment of a needle protection arrangement according to the invention, and through an injection needle shown for better illustration,

Fig. 2 is an exploded sectional view of an injection needle, a receiving element for receiving it, and a movable cam element, seen along the line H-II of Fig. 3,

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Fig. 3 is a view similar to Fig. 2, but in the non-cut state, and rotated by 90° relative to Fig. 2,

Fig. 4 is a representation analogous to Fig. 2 and 3, but in a three-dimensional representation,

Fig. 5 the receiving element and the movable cam element of Fig. 2 to 4 in the assembled state,

Fig. 6 is a plan view of the arrangement of Fig. 5, seen in the direction of an arrow VI of Fig. 5,

Fig. 7 is a sectional view of a part of the needle protection cap shown in Fig. 1, in a three-dimensional view, and partially cut away,

Fig. 8 is a perspective view of the part of the needle protection cap shown in Fig. 7 as well as a lower and an upper end part, before assembly, in a perspective view and partially cut away,

Fig. 9 is a three-dimensional representation analogous to Fig. 8, but after the needle protection cap has been mounted, whereby a cam curve 72 has been created; in practice, the needle protection cap is mounted in conjunction with the parts of Fig. 1,

Fig. 10 is a three-dimensional, exploded view of the parts shown schematically in Fig. 1,

Fig. 11 a development of the cam curve 72, only partially visible in Fig. 9, on the inside of the needle protection cap,

Fig. 12 an enlarged detail of Fig. 11,

Fig. 13 a needle protection arrangement analogous to Fig. 1 in the assembled state on

an injection device and in position A of Fig. 11 and 12, i.e. in a position in which the needle protection cap 70 is blocked,

Fig. 14 is a view similar to Fig. 13, but in position B of Figs. 11 and 12, i.e. also a position in which the needle protection cap 70 is blocked,

Fig. 15 is a view similar to Fig. 13 and 14, but after an injection, and in position C of Fig. 11 and 12,

Fig. 16 is a view of the arrangement according to Figs. 13 to 15, but after the needle has been withdrawn from the patient and in position D of Figs. 11 and 12, in which the needle protection cap is blocked,

Fig. 17 shows a first preferred variant of Fig. 1, in which the injection needle 30' is an integral part of the needle protection arrangement, and

Fig. 18 shows a second preferred variant of Fig. 1, namely a needle protection arrangement with integrated injection needle 30"; this arrangement serves for fastening to a fastening cone of a conventional injection syringe (indicated by dash-dotted lines).

In the following description, as is usual for medical devices, the terms proximal and distal are used as follows: Proximal = facing the patient, i.e. top in Fig. 1. Distal = facing away from the patient, i.e. bottom in Fig. 1. (The terms proximal and distal refer to the middle of the patient's body.) The terms left, right, top, bottom refer to the respective figure. Identical or equivalent parts are designated with the same reference symbols and are usually only described once.

Fig. 1 shows at the bottom - just for better orientation of the reader - a conventional injection needle 30 which is attached to a needle carrier 32 which is provided on the inside with an internal thread 34 for attachment to an external thread 35 of an injection device 36 (Fig. 13 to 16). In

This injection device 36 usually contains a cartridge 38 containing a liquid 40 to be injected, and this cartridge 38 is provided at its proximal end with a rubber membrane 42 which is pierced by the distal part 30d of the needle 30, as is known to those skilled in the art. The injection needle 30 shows that all illustrations are greatly enlarged for reasons of clarity.

A needle protection arrangement 44 has a receiving part 46 made of a suitable elastic plastic. The receiving part 46 is provided with a substantially cylindrical outer side 47 and a recess 48, the latter being pushed onto the outer side 50 of the needle carrier 32 during use as shown in Fig. 13. The tolerances are selected such that the receiving part 46 is securely but detachably attached to the needle carrier 32.

The receiving part 46 has an inwardly projecting shoulder 52 with a central opening 54 for the needle 30 and a fastening element 56 associated therewith. As can be seen from Fig. 13, the shoulder 52 forms a stop for the part 32.

The receiving part 46 has on its proximal side four spring-loaded, hook-like parts 58 extending in the axial direction (see Fig. 4), which together define on their outside an annular groove 60 in which a movable cam element 62 in the form of a cam ring is rotatably mounted. In this embodiment, the cam element 62 has on its outside two radially projecting cams 64, which are arranged on diametrically opposite sides of the cam ring 62. If necessary, for example, only one cam 64 would be possible, or four evenly distributed cams at intervals of 90° each.

As can be seen from Fig. 4 and 5, the cam ring 62 is rotatably mounted in the ring groove 60 by pressing it from above. The rotation takes place with a certain amount of friction. The hooks 58 spring radially inwards during assembly and thereby lock the cam ring 62 in its position according to Fig. 5.

According to Fig. 1, a needle protection cap 70 is attached to the receiving part 46 so that it can be moved longitudinally. It has a guide or

Cam curve 72, which is shown in three-dimensional form in Fig. 9 and in developed form in Figs. 11 and 12. In Figs. 1 and 13 to 18, the cam curve 72 is only indicated very schematically, but not shown in detail, so as not to make the understanding of the invention more difficult.

The two cams 64 of the cam ring 62 engage with the cam curve 72 and are moved in the circumferential direction by the cam curve 72 during the injection process, i.e. the cam ring 62 is rotated by a certain angle during the course of an injection, which is explained in more detail below.

The needle protection cap 70 consists of three plastic parts, namely a substantially hollow cylindrical part 74, which is shown for example in Fig. 7 and can also be referred to as the outer body, a proximal end part or cover 76 (cf. Figs. 8 to 10) which is connected to the hollow cylindrical part 74 via a locking connection 78 (Fig. 1), and a distal end part 80 which is connected to the hollow cylindrical part 74 via a locking connection 82 (Fig. 1). The proximal end part has a recess 77 for the needle 30 in its center. The distal end part 80 is designed on its inside approximately in the form of a hollow cylinder 81 which slides on the outside 47 of the receiving part 46.

As is particularly clear from Fig. 4, the receiving part 46 has in its essentially cylindrical outer side 47 four longitudinal grooves 83 extending in the axial direction, into which corresponding complementary projections 89 (Figs. 8 to 10) on the inner side of the end part 80 engage, whereby the needle protection cap 44 is guided axially and non-rotatably on the receiving part 46.

It should be noted that such an axial guide is advantageous in terms of the principle of the invention, but is not absolutely necessary, since the needle protection cap 44 is not rotated during use. However, the axial guide is preferred in order to reliably rule out errors during handling. Instead of four longitudinal grooves 83, a single longitudinal groove would also be sufficient for the axial guide, or alternatively a projection running in the axial direction that engages in a corresponding recess in the part 80.

The cam curve 72 is formed jointly by the hollow cylindrical part 74 and the two end parts 76, 80, i.e. these parts are mounted in a predetermined angular position relative to each other, as Fig. 9 clearly shows, and this creates the cam curve 72.

A compression spring 84 is arranged between the proximal end part 76 and the shoulder 52, which is indicated schematically in Fig. 1 and shown in three-dimensional form in Fig. 10. In the shoulder 52, it is guided in an annular groove 85, as well as in an annular groove 87 of the upper end part 76.

As shown in Fig. 7, the hollow cylindrical part 74 has on its essentially cylindrical inner side alternating radially inwardly projecting wide projections 86 and narrow projections 88 which, after assembly, form part of the cam curve 72, cf. Fig. 9. The projections 86, 88 extend, as shown, essentially in the axial direction.

The proximal end part 76 is provided on its outside with an annular bead 90 (Fig. 8) for engaging in an annular groove 92 of the part 74, and also with guide elements 94 for guiding in recesses 96 of the part 74 to ensure assembly in the correct angular position. On its distal side, the proximal end part 76 is provided with teeth 98, see Figs. 8 to 10. These have a roughly sawtooth-like shape.

The distal end part 80 is provided on its outside with an annular bead 102 and guide elements 104 for engaging in an annular groove 106 and guide recesses 108 of the part 74. On its proximal side, the part 80 has teeth 110, see Figs. 8 to 10. The number of teeth 110 is twice as high as the number of teeth 98.

As Fig. 9 shows, the axial projections 86, 88 of the hollow cylindrical part 74 and the teeth 98, 110 of the two end parts 76, 80 together form the cam curve 72, which is shown in developed form in Fig. 11 and 12. In Fig. 9, the limiting elements of the cam curve 72 formed by the two end elements 76, 80 are highlighted in gray for better illustration.

As can be seen from Fig. 9, the teeth 98, 110 preferably rest with their outer side against the substantially cylindrical inner side of the hollow cylindrical part 74.

The cams 64 of the cam ring 62 can only move within the cam curve 72, and this is limited in Fig. 9 at the top by the teeth 98, at the bottom by the teeth 110, and in the peripheral direction by the projections 86, 88 on the inside of the part 74.

As shown in Fig. 5, the cams 64 preferably have the cross-sectional shape of a polygon. If one assumes a clock, then - always in relation to a horizontal line - in the area from approximately 0 to 3 o'clock there extends an inclined surface at an angle of approximately 135°, in the area around 3 o'clock an inclined surface 118 at an angle of approximately 90°, in the subsequent area up to 6 o'clock a surface 120 at an angle of approximately 30°, in the subsequent area up to approximately 8 o'clock an inclined surface 122 at an angle of approximately 135°, in the subsequent area up to approximately 10 o'clock an inclined surface 124 at an angle of approximately 90°, and in the area from 10 to 12 o'clock an inclined surface 126 at an angle of approximately 45°. It should be emphasized that these angle specifications are preferred values that can vary within wide limits. For reasons of strength, the cam 64 requires a certain cross-sectional area. If a metal cam is used, it may simply have the shape of a cylindrical pin.

Fig. 11 shows the cam curve 72 in a developed form which extends over 360°. Fig. 12 shows a greatly enlarged section of it. For reasons of clarity, only one of the two cams 64 is shown. At the beginning of a cycle, this is in a position A in which it is pressed by the spring 84 with its surfaces 120, 122 against complementary surfaces 130, 132 of the teeth 110 of the lower end part 80. The transition 134 between the surfaces 130, 132 lies opposite an inclined surface 136 of the wide projection 86 which runs essentially parallel to the surface 126 of the cam 64 and at a small distance d from it when the cam is in position A.

The inclined surface 136 ends on the right at a transition point 138 and there merges into an inclined surface 140 which runs approximately parallel to the inclined surface 116 of the cam 64.

The inclined surface 130 extends to the right to a maximum 142, which lies to the left of the transition point 138, and at the point 142 merges into an inclined surface 144, which runs essentially parallel to the inclined surface 122 of the cam 64. The inclined surface 144 extends to a transition point 146 and there merges into an inclined surface 148, which runs approximately parallel to the inclined surface 130. The inclined surface 148 merges into a left side surface 150 of the narrow projection 88, the right side surface 152 of which merges into the inclined surface 132.

The inclined surface 140 merges into the right side surface 154 of the wide projection 86, and this merges on the proximal side, i.e. at the top in Fig. 11 and 12, into an inclined surface 156 of an upper tooth 98, which runs at approximately 15° to the horizontal and extends to a point 158 which is to the right of the narrow projection 88. At point 158 it merges into a short inclined surface 160, the inclination and length of which correspond approximately to that of the surface 116 of the cam 64, and which merges into a left side surface 162 of the wide projection 86.

The cam curve 72 extends, as can be clearly seen from Fig. 11 and 12, between the described inclined and side surfaces and its course resembles the meander of a river bed. If you look at Fig. 12 from the top of the drawing, you can see that the cam curve 72 has the shape of an M in the area 131 and the shape of a V in the area 133. In the illustration in Fig. 12, it has the shape of a W in the area 131.

Before an injection, the needle protection arrangement 44 of Fig. 1 is pushed onto the outside 50 of the needle holder 32 in the direction of an arrow 97. The cam 64 is in position A, i.e. is pressed against the inclined surfaces 130 and 132 by the spring 84. This corresponds to the position shown in Fig. 13. The needle 30 is covered by the needle protection cap 70 in this position.

If the needle protection cap 70 is now subjected to a force P (Fig. 14) in the distal direction, it can only move to the position shown in Fig. 14, in which the needle 30 is still fully covered, because the cam then strikes the inclined surface 136 with its surface 126 (Fig. 5 and 12) and slides along this to a position B (Fig. 11, 12), in which it strikes the inclined surface 140. This causes the cam ring 62 to rotate, ie with reference to Fig. 11 and 12 the cam 64 moves to the right.

If the force P (Fig. 14) is then made zero, the force 4k of the spring 84 moves the cam 64 into a position C in which the surfaces

120, 122 of the cam 64 rest against the inclined surfaces 144, 148. The cam ring 62 is thereby rotated further to the right.

In position C, the needle protection cap 70 is unlocked and, as shown in Fig. 15, an injection can be made from position C by piercing in the direction of an arrow 166, whereby the needle protection cap 70, as shown, moves in the distal direction and injection fluid 40' is injected into the patient's tissue 168. The cam 64 then comes into contact with the inclined surface 156 of a tooth 98 and is rotated further to the right by this into position D, where it forms a stop for the needle protection cap 70 and limits its piercing depth.

Fig. 16 shows the position after the needle 30 has been pulled out. The cam 64 then comes into contact with the inclined surface 132 (Fig. 12) due to the force of the spring 84 and slides along it to a position E, where its surface 120 rests against the inclined surface 130. The position E corresponds to the position A described above. Compared to the position A, however, the cam ring 62 in the position E is rotated further by 36078 = 45°, and the needle protection cap 70 is blocked again in this position, so that contamination by the used needle 30 is prevented.

After the injection, the needle protection arrangement 44 is removed from the needle 30, as indicated in Fig. 1 by an arrow 99. The needle 30 is unscrewed with a suitable device and replaced with a new, sterile

Needle is replaced and the needle protection assembly 44 is placed on this new needle 30 and can then be used again.

If a needle protection arrangement 44' (Fig. 17) is to be used for only a single injection, the cam curve 72 begins shortly before point A (Fig. 12) and ends shortly after point E. This is the case with the version according to Fig. 17, in which the needle 30' is an integral part of the needle protection arrangement 44'. Since Fig. 19 otherwise corresponds to the previous figures, a new description can be omitted in the interests of brevity.

During assembly, the cam ring 62 is first mounted and the lower end part 80 is pressed into the hollow cylindrical part 74. This is then pushed onto the receiving part 46 from below, as shown in Fig. 1. The two cams 64 slide into the cam curve 72, which is open at the top in this state. The spring 84 is then inserted and the upper end part 76 is pressed - in the correct angular position - into the proximal end of the hollow cylindrical part 74. The needle protection arrangement is now complete and is usually sterilized and packaged for sale.

Fig. 18 shows a variant of Fig. 17. While the arrangement 44' according to Fig. 17 is usually used in connection with automatic injectors, the needle protection arrangement 44" of Fig. 18 serves for attachment to the cone 174 of a conventional syringe 176, which is indicated in dash-dotted lines in Fig. 18 and only very schematically in order to facilitate the understanding of the invention.

In the base part 46" of the needle protection arrangement 44" there is a truncated cone-shaped recess 180, which at the distal end merges into a truncated cone 182 with a larger opening angle, which makes it easier to place the arrangement 44" on an injection syringe 176. Before an injection, the base part 46" with its recess 180 is placed on the cone 174 of the syringe 176, as is known from conventional injection needles.

An injection needle 30" is secured by plastic syringes in a proximal projection 184 of the base part 46". In the state before an injection, it is safely covered by the needle protection cap 74. This is designed identically to that in the previous figures, as are its two end parts 76 and 80, so that for the sake of brevity, reference can be made to the previous description.

The base part 46" is, as in the previous figures, provided with spring-loaded locking projections 58, on which a cam ring 62 with its two cams 64 is fastened. The mode of operation therefore corresponds to the mode of operation which was described in detail in the previous figures.

The arrangement according to Fig. 18 also makes it possible to significantly reduce the risk of contamination from a used injection needle 30" in conventional injection syringes 176, such as those used in millions every year, since this needle is surrounded by the needle protection sleeve 74 along its entire length after an injection has been completed. In this case, as described in Figs. 11 and 12, the cam curve is not designed to be self-contained, but rather, for example in Fig. 12, only the part of the cam curve that begins shortly before point A and ends shortly after point E is used. In addition, the cam 64 can be permanently locked at point E in this case, so that any movement of the needle protection sleeve is blocked after an injection has been completed. This is possible because in this case it is a disposable syringe and the needle 30" is therefore only used once.

Naturally, many variations and modifications are possible within the scope of the present invention. In particular, a kinematic reversal is possible in the sense that the cam ring is provided on the needle protection cap 70, with its cams projecting radially inwards and engaging a cam curve which is then provided on the part 46. However, since this would lead to a larger diameter of the arrangement, the versions shown are currently preferred. The outside of an arrangement according to the invention can

can be designed in many different ways in terms of their optical and haptic design.

Claims (20)

1. Needle protection arrangement for an injection needle ( 30 ), with a first part ( 46 ; 46 '; 46 ") connectable or connected to the injection needle ( 30 ; 30 '; 30 "), with a second part ( 70 ), which - is designed as a needle protection cap with a needle outlet opening ( 77 ) provided at its proximal end region, - between - a proximal end position region in which it covers the injection needle ( 30 ; 30 '; 30 "), - and a distal end position region in which the injection needle ( 30 ; 30 '; 30 ") protrudes from the needle outlet opening ( 77 ), is movable, and - is subjected to an elastic force ( 84 ) in the direction away from the first part ( 46 ; 46 '; 46 "), further comprising a cam element ( 62 ) provided on one of the two parts ( 70 or 46 ; 46 '; 46 ") and movable relative to this part, which has at least one cam ( 64 ) which engages in a cam curve ( 72 ) provided on the other of the two parts ( 46 ; 46 '; 46 " or 70 ), which is designed such that in the proximal end position region of the needle protection cap ( 70 ), the cam ( 64 ) and cam curve ( 72 ) in their interaction in at least one blocking position (A, B) of the cam element ( 62 ) essentially block a displacement of the second part ( 70 ) in the distal direction. 2. Needle protection arrangement, in which the cam curve ( 72 ) has at least one inclined surface ( 132 , 136 , 144 , 156 ) which, through its interaction with the associated cam ( 64 ), promotes a movement of the cam element ( 62 ) in a preferred direction when the second part ( 70 ) is displaced between its end position regions. 3. Needle protection arrangement according to claim 1 or 2, in which the cam curve ( 72 ), which has a proximal and a distal end region, has an inclined surface ( 156 ) at its proximal end region, which, through its interaction with the associated cam ( 64 ), causes a movement of the cam element ( 62 ) in the preferred direction by a first predetermined path into a corresponding position (D) when the injection needle ( 30 ; 30 '; 30 ") is inserted into the patient. 4. Needle protection arrangement according to claim 2 or 3, in which the cam curve ( 72 ), which has a proximal and a distal end region, has an inclined surface ( 132 ) at its distal end region, which, after the injection needle ( 30 ; 30 '; 30 ") has been pulled out of the patient, in cooperation with the cam ( 64 ) assigned to it, causes a movement of the cam element ( 62 ) in the preferred direction by a second predetermined path into the blocking position (E) or into one of a plurality of blocking positions in which the cam ( 64 ) and cam curve ( 72 ) in their cooperation essentially block an axial displacement of the second part ( 70 ) in the distal direction. 5. Needle protection arrangement according to claim 4, in which the cam curve ( 72 ) has an inclined surface ( 136 ) at its distal end region, which, when the needle protection cap ( 70 ) is displaced distally from the blocking position (A), in cooperation with the cam ( 64 ) assigned to it, causes a movement of the cam element ( 62 ) in the preferred direction by a third predetermined angle of rotation into an intermediate position (B). 6. Needle protection arrangement according to claim 5, in which the cam curve ( 72 ) has an inclined surface ( 144 ) at its distal end region, which, when the needle protection cap ( 70 ) is displaced proximally from the intermediate position (B), in cooperation with the cam ( 64 ) assigned to it, causes a movement of the cam element ( 62 ) in the preferred direction by a fourth predetermined path into a release position (C), from which it is possible to insert the injection needle ( 30 ; 30 '; 30 "). 7. Needle protection arrangement according to one of the preceding claims, in which the cam ( 64 ), seen in a plan view substantially orthogonal to the plane of the cam curve ( 72 ), has approximately the shape of a polygon ( Fig. 5). 8. Needle protection arrangement according to one of the preceding claims, in which the cam curve ( 72 ) is formed substantially meander-shaped. 9. Needle protection arrangement according to claim 8, wherein the substantially meander-shaped cam curve ( 72 ) is closed in itself. 10. A needle guard assembly according to any preceding claim, wherein the cam curve ( 72 ), viewed in plan view with its proximal side upward, has at least one portion ( 131 ) having approximately the shape of a W. 11. A needle guard assembly according to any preceding claim, wherein the cam curve ( 72 ), viewed in a plan view with its distal side upward, has at least one portion ( 133 ) having approximately the shape of a V. 12. A needle guard assembly according to any preceding claim, wherein the cam curve ( 72 ), viewed in a plan view with its distal side upward, has at least one portion ( 131 ) having approximately the shape of an M. 13. Needle protection arrangement according to one of the preceding claims, in which the cam curve ( 72 ) is provided on the inside of the needle protection cap ( 70 ). 14. Needle protection assembly according to claim 13, wherein the needle protection cap ( 70 ) is formed from at least two elements ( 74 , 76 , 80 ) to facilitate its assembly on the first part ( 46 ; 46 '; 46 "). 15. Needle protection arrangement according to claim 14, wherein the cam curve ( 72 ) of the needle protection cap ( 70 ) is formed by a plurality of elements ( 74 , 76 , 80 ) of the needle protection cap ( 70 ). 16. Needle protection arrangement according to one of the preceding claims, in which the movable cam element is designed in the manner of a ring ( 62 ) which is rotatably mounted on a part ( 58 ) associated with it. 17. A needle guard assembly according to claim 16, wherein the ring ( 62 ) is frictionally mounted to prevent accidental change in its rotational position. 20. Needle protection arrangement according to one of the preceding claims, in which the needle protection cap ( 70 ) is guided substantially non-rotatably relative to the first part ( 46 ; 46 '; 46 "). 21. Needle protection arrangement according to one or more of the preceding claims, in which the first part ( 46 ") is firmly connected to the injection needle ( 30 ") and is provided on its distal side with a truncated cone-shaped recess ( 180 ) for connection to an approximately complementary truncated cone of an injection syringe ( 176 ). 22. Needle protection arrangement according to claim 21, in which the first part ( 46 ") is provided on the proximal side of its frusto-conical recess ( 180 ) with an extension ( 184 ) in which the injection needle ( 30 ") is fastened with its distal section.