Source: http://www.google.ca/patents/CA2191472C
Timestamp: 2018-01-18 12:10:15
Document Index: 238342216

Matched Legal Cases: ['art 60', 'art 82', 'art 82', 'art 82', 'art 82', 'arts 1', 'art 73', 'art 132', 'art 132', 'art 132', 'art 132', 'art 132', 'art 150', 'art 132', 'art 132', 'art 132', 'art 150', 'art 132', 'art 132', 'art 150', 'art 132', 'art 150', 'art 132', 'art 150', 'art 186', 'art 186', 'art 150', 'art 132', 'art 132', 'art 150', 'art 132', 'art 150', 'art 186', 'art 186', 'art 186', 'art 186', 'arts 208', 'art 209', 'art 210', 'art 132', 'art 186', 'art 186', 'art 186', 'art 186', 'art 186', 'art 234', 'art 234', 'art 186', 'art 186', 'art 234', 'art 66', 'art 132', 'art 234', 'art 132', 'art 234', 'art 132', 'art 150', 'art 132', 'art 132', 'art 150', 'arts 132', 'art 186', 'art 234', 'art 132', 'art 132', 'art 234', 'art 234', 'art 150', 'art 132', 'art 132', 'art 234', 'art 132']

Patent CA2191472C - Injection device - Google Patents
The invention relates to an injection device (10) with a housing (15) and a container (12) for an injection fluid which can slide in relation to the housing between a distal and a proximal end position. The device also has a slide rod (14) which acts on a plunger (23) in the container (12) to expel fluid...http://www.google.ca/patents/CA2191472C?cl=en&utm_source=gb-gplus-sharePatent CA2191472C - Injection device
Publication number CA2191472 C
Application number CA 2191472
Also published as CA2191472A1, DE19519147A1, DE29522418U1, DE59510404D1, DE59510817D1, EP0762904A2, EP0762904B1, EP1228777A1, EP1228777B1, US6241709, US20020165500, WO1995032749A2, WO1995032749A3
Publication number CA 2191472, CA 2191472 C, CA 2191472C, CA-C-2191472, CA2191472 C, CA2191472C, PCT/1995/2032, PCT/EP/1995/002032, PCT/EP/1995/02032, PCT/EP/95/002032, PCT/EP/95/02032, PCT/EP1995/002032, PCT/EP1995/02032, PCT/EP1995002032, PCT/EP199502032, PCT/EP95/002032, PCT/EP95/02032, PCT/EP95002032, PCT/EP9502032
Applicant Herbert Bechtold, Jochen Gabriel, Medico Development Investment Company, B D Medico S.A.R.L., Haselmeier Sarl
Classifications (18), Legal Events (2)
CA 2191472 C
1. An injection device comprising a housing, a retainer axially movable within said housing for movement therein, during an injection, between a distal position and a proximal position thereof, said proximal position being closer to a patient receiving an injection than said distal position, a fluid container within said retainer, a plunger axially movable within said fluid container, a driving member axially displaceable within said housing, a toothed rod having a plurality of teeth arranged thereon in a longitudinal direction, said toothed rod being disposed in said housing for axial displacement therein and for acting on said plunger to express fluid from said fluid container during an injection, a first coupling device, cooperating with teeth on the toothed rod, being provided on said retainer, said first coupling device normally locking said toothed rod to said retainer but permitting relative axial movement therebetween while said retainer is not within a first predetermined axial position range inside said housing and said toothed rod is moving in a predetermined axial rod movement direction, and a second coupling device, cooperating with teeth on the toothed rod, being provided on said driving member, said second coupling device normally locking said driving member to said toothed rod but permitting relative axial movement therebetween while said driving member is not within a second predetermined axial position range inside said housing and said driving member is moving in a predetermined driving member axial movement direction.
2. The injection device according to claim 1, wherein, said second coupling device is so formed that the distal position of the retainer also constitutes a limit for distal movement of the pushrod.
4. The injection device according to claim 1, wherein in a proximal position range of the retainer, the second coupling device causes engagement between the driving member and the toothed rod during movement in both the proximal and the distal directions.
5. An injection device, comprising:
a housing, a retainer axially movable within said housing for movement therein, during an injection, between a distal position and a proximal position thereof, said proximal position being closer to a patient receiving an injection than said distal position, a fluid container within said retainer, a plunger axially movable within said fluid container, a driving member axially displaceable within said housing, a toothed rod disposed in said housing for axial displacement therein and for acting on said plunger to express fluid from said fluid container during an injection, a first coupling device provided on said retainer and cooperating with teeth of said toothed rod, said coupling device normally locking said toothed rod to said retainer but permitting relative axial movement therebetween while said retainer is not within a first predetermined axial position range inside said housing and said toothed rod is moving in a predetermined axial rod movement direction, and a second coupling device provided on said driving member, and cooperating with teeth of said toothed rod, said second coupling device normally locking said driving member to said toothed rod but permitting relative axial movement therebetween while said driving member is not within a second determined axial position range inside said housing and said driving member is moving in a predetermined driving member axial movement direction, and further comprising, coupled to the driving member, a detent mechanism, and a spring, acting upon the driving member in the proximal direction, and adapted to be compressed by moving the driving member and detent mechanism in the distal direction, said detent mechanism engaging against a fixed portion of said housing when a predetermined cocked position is reached.
6. The injection device according to claim 5, wherein the housing is formed with a radial opening therein, a clip, provided on the outside of the housing, being movable at said radial opening against the detent mechanism inside the housing to release the detent mechanism and to thus trigger an injection process.
7. The injection device according to claim 1, wherein the driving member is connected to an actuating grippable member located on a distal portion of the device, for moving the driving member into its cocked position.
9. The injection device according to claim 1, wherein the first coupling device on the retainer comprises a member laterally movable into and out of engagement with the toothed rod.
10. The injection device according to claim 9, wherein the member connected to the retainer elastically engages said pushrod, at least in the proximal end position of the retainer.
11. The injection device according to claim 9, wherein said first coupling device is axially movable together with said retainer.
12. The injection device according to claim 1, wherein the second coupling device has a shape complementary to that of the pushrod, for engagement with the pushrod and engages elastically with the toothed rod at least in the distal end position range of the retainer.
13. The injection device according to claim 12, wherein the second coupling device is prevented by a member secured to the housing from moving elastically away from the toothed rod, depending upon the position of the retainer.
14. The injection device according to claim 1, wherein a stop is provided on an inner surface of the housing for limiting movement of the toothed rod relative to the housing.
15. The injection device according to claim 1, wherein the retainer comprises two interengaging sections, allowing an adjustment of the retainer's length.
16. The injection device according to claim 15, wherein the retainer comprises a proximal section and a distal section that are connected to each other by an adjustable connection allowing an adjustment of the overall length of the retainer.
19. An injection device having a housing, comprising an injection fluid container disposed in said housing, a toothed rod movable in relation to the housing to expel fluid from said container, and a retainer serving to hold the container and movable in the housing between a proximal and a distal position, said retainer comprising a proximal retainer portion and a distal retainer portion, said retainer portions being axially displaceable relative to each other for permanently adjusting the length of said retainer.
20. The injection device according to claim 19, wherein, in a distal position range thereof, the retainer has abutment means, determining at least one end position thereof relative to the housing and wherein length adjustment of the retainer, by adjusting interengagement of sections thereof, is carried out relative to the abutment means so that, when the length of the retainer is changed, the position of the container relative to the toothed rod is changed.
21. The injection device according to claim 19, wherein the device for adjusting length comprises a micro-detent mechanism connecting a proximal section and a distal section of the retainer to each other in an adjustable way.
22. An injection device, comprising a housing, a retainer axially movable within said housing for movement therein, during an injection, between a distal position and a proximal position thereof, the proximal position being closer to a patient receiving an injection than the distal position, a fluid container within said retainer, a plunger axially movable within said fluid container, a driving member axially displaceable within said housing, a toothed rod disposed in said housing for axial displacement therein and for acting on said plunger to express fluid from said fluid container during an injection, a first coupling device provided on said retainer and cooperating with teeth on said toothed rod, said first coupling device normally locking said toothed rod to said retainer but permitting relative axial movement therebetween while said retainer is not within a first predetermined axial position range inside said housing and said toothed rod is moving in a predetermined axial rod movement direction, and a second coupling device provided on said driving member and cooperating with teeth on said toothed rod, said second coupling device normally locking said driving member to said toothed rod but permitting relative axial movement therebetween while said driving member is not within a second predetermined axial position range inside said housing and said driving member is moving in a predetermined driving member axial movement direction, and wherein the housing comprises two parts linearly movable relative to each other, and a device is provided for changing the relative position of the housing parts by linearly moving them relative to each other.
23. The injection device according to claim 22, wherein a first housing part is provided for guiding the retainer holding the injection fluid container and a second housing part, movable relative to said first housing part, comprises detent means for locking of a detent mechanism provided on the driving member.
24. The injection device according to claim 23, wherein the second housing part is formed with a radial opening therein, and a clip on the outside of the second housing part is provided for releasing, by actuation via said radial opening, the detent connection between the detent means and the detent mechanism inside said housing.
26. The injection device according to claim 22, further comprising a guide means for linearly guiding said housing parts that are movable relative to each other.
28. The injection device according to claim 27, wherein an outer one of said housing parts is provided with at least one elongated recess through which a part of the inner one of said housing parts protrudes radially.
32. The injection device according to claim 1, wherein the second coupling device has two engaging members provided with engaging elements adapted to engage corresponding rows of teeth on said pushrod.
33. The injection device according to claim 31, wherein the toothed rod serving as a pushrod has a rectangular cross-section and, on a first pair of opposing sides, is provided with rows of teeth for engagement with the first coupling device, and, on the second pair of opposing sides, is provided with rows of teeth for engagement with the second coupling device.
35. The injection device according to claim 34, wherein one of the rows of teeth on the opposing sides of said toothed rod, and the engaging elements on engaging members which elastically engage these opposing rows of teeth, are offset from each other in an axial direction in order to permit, selectively:
a full engagement of an engaging element of the first of two elastic engaging members with the associated row of teeth of the toothed rod, while an engaging element of the second of two elastic engaging members is not in full engagement with its associated row of teeth but elastically applied thereagainst, or a full engagement of an engaging element of the second of two elastic engaging members with the associated row of teeth of the toothed rod, while the engaging element of the first of two elastic engaging members is not in full engagement with its associated row of teeth but elastically applied thereagainst, thus allowing adjustment of the injection device in steps smaller than one tooth division of the rows of teeth.
36. An injection device having a housing for receiving a container for a fluid to be injected, an actuating member for actuating said injection device, a toothed rod, having a longitudinal axis and being axially movable in response to said actuating member to expel fluid from a container disposed in the housing, and an axially movable part which engages against said toothed rod, wherein, in accordance with the, invention, the toothed rod, viewed in cross section transverse to its longitudinal axis, is polygonal;
said rows of teeth each have a predetermined tooth division, said axially movable part comprises a plurality of engaging members, and each engaging member is formed with at least one engaging element having a shape complementary to a cooperating one of said rows of teeth and each engaging member is elastically biassed against said cooperating row of teeth, and wherein, in order to facilitate finer adjustment of an axial position of said toothed rod within said housing, there is an axial offset among at least one of the respective rows of teeth with respect to each other, and the engaging elements on the respective engaging members with respect to each other.
39. The injection device according to claim 36, wherein the toothed rod has a rectangular cross-section, and said advancing part has two engaging members cooperating with rows of teeth on opposing sides of said toothed rod .
41. The injection device according to claim 16, wherein the adjustable connection comprises a micro-detent mechanism.
43. The injection device according to claim 36, wherein said axially movable part is movable between a first position wherein a first one of said engaging members is fully engaged with a first one of said rows of teeth and a second one of said engaging members is elastically biassed against, but not fully engaged with, a second one of said rows of teeth, and a second position wherein said first one of said engaging members is elastically biassed against, but not fully engaged with, said first one of said rows of teeth and said second one of said engaging members is fully engaged with said second one of said rows of teeth, whereby said axial position of said toothed rod within said housing can be adjusted more finely than a tooth pitch spacing of said teeth.
2~91~72 INJECTION DEVICE
A great number of semiautomatic and fully automatic injection devices have been disclosed. Their construction is often very complex so that manufacturing costs are high. If after being used, a device is not intended for reuse but for disposal or recycling, then a device of this kind has to be composed of few parts and be very cheap to manufacture. Most injection devices which operate semi-automatically or fully automatically do not meet this demand. See for example the fully automatic injection devices according to DE 39 14 818-A1, DE 40 13 769-A1, or DE-UM 92 00 192 (all by Adamaszek). These devices require a first spring for the insertion of the needle and a second spring for the injection of the fluid, and furthermore, corresponding control devices that trigger the injection process by means of the second spring only when the insertion of the needle is finished, as a result of which these devices become very complex and expensive.
This object is achieved according to the invention by an injection device comprising a housing and an injection fluid container which is displaceable in relation to this housing, between a distal and a proximal end position. The device also comprises a pushrod movable in relation to the housing to expel fluid from the container. A first connecting device, which acts in a position-dependent and/or direction-dependent manner, is provided between the pushrod and the container. The connecting device between the pushrod and the container is thus preferably a controlled connecting X191 X7'2 device, i.e. the container follows the motion of the pushrod only when it is logical and required for the operation of the device. Preferably, this connecting device is controlled by the position of the container relative to the housing.
In a movement of the pushrod in the distal direction, the first connecting device is advantageously adapted to produce a unidirectional, positive connection between the pushrod and the container and to move the latter along with the pushrod in the distal direction, and it is furthermore formed to convert a movement of the pushrod in the proximal direction into a corresponding movement of the container in the proximal direction as long as the container is not prevented from moving in the proximal direction in the housing.
Therefore, during a distal movement, the pushrod is positively coupled to the container, that is, their movements are "positively synchronized", but a proximal movement of the pushrod will move the container only until it has reached its proximal end position in the housing, for example, whereafter the proximal movement of the pushrod will occur independently of the container, in order to expel fluid from the container.
Also, in a proximal position region of the container, the second connecting device advantageously produces a connection between the drive mechanism and the pushrod in both the proximal and the distal direction.
After an injection, this makes it possible to bring the container into its distal end position.
A fully automatic injection is permitted in a simple manner with such an injection device wherein the drive mechanism is associated with a spring and a detent mechanism; the spring, which in particular is a spring made of plastic material, acts on the drive mechanism in the proximal direction and can be compressed by sliding the detent mechanism in the distal direction where the detent mechanism engages when it reaches a predetermined cocked position. In its cocked position, the spring thus permits a fully automatic injection process via the second and the first connecting device.
Because of the energy stored in this spring after being compressed, first a needle connected to the container is inserted and then the fluid is expelled from the container and injected. This permits the manufacture of a very simple, fully-automatic injector made of few parts. However, a device of this kind can also be actuated manually, that is, without a spring, wherein the user first inserts the needle by actuating a single actuation member and then injects the fluid in the set quantity.
According to an extraordinarily advantageous embodiment of the invention, the length of the retainer is adjustable. This permits the necessary adjusting procedures because the containers are in fact fixed in size, but always have manufacturing tolerances, as does the pushrod usually disposed in them, and these tolerances can be compensated for in a simple way by adjusting the length of the retainer. To that end, the retainer advantageously has a proximal section and a distal section which are connected to each other by an adjustable connection which permits a change and in particular a shortening of the overall length of the retainer, for example by means of an axial force, particularly through the use of a micro-detent mechanism. A micro-detent mechanism. of this kind, or for example a corresponding screw connection with a fine pitch thread, permits a fine adjustment of the length of the retainer and hence a very exact adjustment, as is desired for an exact maintenance of the injection dosage.
In its proximal end position, the retainer advantageously abuts with its distal end against a proximal end section of the drive member. This permits a simple fine adjustment by means of an axial force, which acts on the proximal end of the retainer, for example, and makes a micro-detent mechanism slide. Another solution to the task presented is achieved by an injection device having a housing, comprising an injection fluid container disposed in this housing, further comprising a pushrod movable in relation to the housing to expel fluid from this container, further comprising a retainer serving to hold the;container and movable in the housing between a proximal and a distal end position, and comprising. a device for adjusting the length of this retainer. An embodiment of this kind permits a simple manufacture and final adjustment of an injection device of this kind. Further embodiments of the invention are also described.
An extraordinarily advantageous improvement of the invention relates to an injection device in which the housing is formed of at feast two parts and a device is provided for changing the relative position of these housing parts, in particular by means of linear relative displacement. In a simple way, this permits an adjustment of the injection dosage, in particular if a first housing-part is provided for guiding the retainer that receives the injection fluid container and a second housing part that is, displaceable in relation to the first one has detent means for engaging with a detent mechanism provided on the drive mechanism. Since in this manner, the detent means can change its position in relation to the housing, the distance that the drive mechanism covers until it engages can be changed and this means that the user can vary the injection dosage by displacing the part with the detent means.in relation to the other housing part.
A further refinement of the invention relates to an injection device in which the rows of teeth on the opposite sides of a toothed rod serving as the pushrod and/or the teeth on elements elastically engaged with these rows of teeth are axially offset in relation to each otherun order to - ~lyi~+i'2 alternatively permit the teeth of the first of two resilient elements to completely engage with the row of teeth associated with it, or to permit the teeth of the second of two resilient elements to completely engage with the row of teeth associated with it on the pushrod, and in this way, to permit the injection device to be more finely adjusted. This turns out to be particularly advantageous when the intent is to set very small injection dosages, which correspond to movements of the pushrod in a cartridge, which movements are shorter than 1 mm.
Figs. 1 to 5 are diagrams which represent the chronological course of an injection procedure in schematic form, Figs. 6 and 7 are graphic explanations of details from Figs. 1 to 5, Figs. 8A and 8B show a longitudinal section through a preferred embodiment of an injection device according to the invention, when in the uncocked state, Figs. 9A and 9B are representations analogous to Fig. 8, but in the cocked state, Fig. 10 is a schematic, three-dimensional representation of the proximal end of the pushrod used in the first and second exemplary embodiment, in the form of a toothed rod with an approximately square cross section, Figs 1 1 A and 1 1 B show a longitudinal section analogous to Figs. 8 and 9, but in a plane perpendicular to these two Figs., Fig. 12 shows how a hook of a connecting device engages in the pushrod of Fig. 10, Fig. 13 is an enlarged schematic representation of the detent mechanism between parts of the retainer 54, as also used in the third embodiment below, . - ~?~i4~'2 _7_ Fig. 14 is a three-dimensional representation of an injection device according to a third embodiment of the invention in which the injection dosage can be adjusted, Fig. 15 is a three-dimensional representation analogous to Fig. 14, but for a better view, the housing is shown in a partial cutaway view and in the region of this cutaway, the internal parts of the injection device are not shown, Fig. 16 is a three-dimensional exploded view of internal parts of the injection device of Figs. 14 and 15, Fig. 17 is a three-dimensional exploded view of the housing of Figs.
14 and 15 and a retainer part disposed in it, Fig. 18 is a three-dimensional exploded view of a cartridge, its retainer, and an injection needle, Figs. 19 to 21 are various representations of the injection device according to the third embodiment in longitudinal section and in various positions; the cocking spring is not shown, and in Fig. 21, the release (clip), which would not be visible per se in this longitudinal section, is shown rotated by 45 °, Fig. 22 shows a section along line XXII-XXII in Fig. 21, Fig. 23 shows a section along line XXIII-XXIII in Fig. 21, in the section according to Fig. 23, the internal parts of the injection device are not shown, Fig. 24 is an enlarged detail of area XXIV in Fig. 19, Fig. 25 is an enlarged detail of area XXV in Fig. 20, Fig. 26 is a very schematic three dimensional representation of the pushrod used in the third exemplary embodiment, in the form of a toothed rod, Fig. 27 shows only the upper and lower rows of teeth of the pushrod of Fig. 26, Fig. 28 shows only the left and right rows of teeth of the pushrod of Fig. 26, Fig. 29 is a schematic representation to explain the advancing process with an advance by a half a tooth space, -- ,-, , -8- L;y~4i2 Fig. 30 is an enlarged section shown in perspective, through the toothed rod shown in Fig. 31, where a part of the toothed rod is shown in a cutaway view in order to make the teeth more visible, and Fig. 31 is an enlarged three dimensional representation of a toothed rod, where a part of the toothed rod is shown in a cutaway view in order to make the teeth more visible.
Fig. 1 shows the injection device 10 in its rest position when the spring 1 1 is not cocked (analogous to the representations in Figs. 8A & 8B, Figs. 1 1 A & 1 1 B, and Figs. 19 & 20). Fig. 2 shows the first part of the cocking process of the spring 1 1, in which a container (cartridge) 12 for the fluid to be injected moves from its proximal end position (Fig. 1 ) into its distal end position (Fig. 2) without a detent mechanism 46 already engaging in a detent opening 48 in a predetermined position (cocked position).
Fig. 3 shows the end of the cocking process, in which the spring 1 1 is fully cocked and the injection dosage is set. This corresponds to the representation in Figs. 9A and 9B or to the representation in Fig. 21.
Fig. 5 shows the second phase of an injection, after the insertion of the needle, where Fig. 5 represents the state after the injection of the set fluid quantity. Here, the device is disposed once again in the rest position according to Fig. 1, but the pushrod 14, (which is formed as a toothed rod) is moved in the proximal direction by one tooth space in comparison to Fig.
1, corresponding to the injected quantity of fluid.
The injection device 10 has a housing 15, in which the container 12, received in a retainer 17, is arranged to be axially displaceable between a proximal end position (Figs. 1, 4, & 5) and a distal end position (Figs. 2 &
3). For this purpose, the retainer 17 has a radial projection 18 that can slide in a corresponding recess 20 of the housing 15 in the manner shown, between two axial abutment positions. The container 12 itself is fixed in __ ~?~i~i2 _g_ the retainer 17 in a suitable manner. The container 12 is usually a glass ampoule on whose proximal end an injection needle 22 can be attached in the usual way depicted and in whose distal end a plunger 23 is slidably disposed. Ampoules (cartridges) of this kind are mass produced. If the plunger 23 is moved or shifted in the proximal direction, then fluid is expelled from the container 12 through the needle 22.
The terms "proximal" and "distal" are standard medical terminology;
distal: away from patient, that is, to the right in Figs. 1-5.
The radially outer side 32 (Fig. 6) of the ratchet 27 is controlled by the shape of the radially inner side of the housing 15. In the position according to Figs. 1, 4, and 5, that is, the proximal end position of the container 12, this ratchet 27 can move radially outward, i.e., if the pushrod 14 here is moved proximal direction, the ratchet 27 is slid radially outward and according to Fig. 5, can slide into the next notch 28.
It should be emphasized here that there are many potential variants, of the detent mechanism for engaging in the notches of toothing 28. These are usually elastically deflectable parts whose elastic deflection is blocked outside of the proximal end position, that is, one is dealing with a path-dependent or position-dependent control of this elastic deflectability, which is naturally possible in a multitude of different forms.
The pushrod 14 is surrounded by a drive mechanism 35, formed here, for example, in the form of a tube that is disposed around the pushrod 14 and is used to drive it via a second connecting device. To this end, a detent mechanism is. provided in an axial extension 36 of the drive mechanism 35 in the form of a radially movable, spring-loaded ratchet 38 which is formed in exactly the same way as the ratchet 27 shown in Fig. 6, that is, it can be shifted outwardly, counter to the force of a spring. As shown, the ratchet 38 engages in one of the notches of toothing 28 of pushrod 14, specifically on the upper side as shown in Fig. 1, while ratchet 27 on the lower side i~n Fig: 1 engages in one of the notches of toothing 28 of the pushrod 14.
(This is the reason why teeth or notches are provided on different sides of the pushrod 14, preferably on two opposite sides.) The radially outer end 40 (Fig.. 2) of the ratchet 38 is controlled by the opposing inside surface 42 (Fig.1 ) of the housing 15. As a comparison of Figs.
1 and 2 shows, in the proximal end position range, a radial movement of the ratchet 38 is blocked, i.e. in this region, a movement of the drive mechanism 35 in both directions is completely transmitted to the pushrod 14.
When the position in Fig. 2 is reached, the retainer 17 with th.e container 12 is disposed in its distal end position by the projection 18 being in abutment against the distal end 20d of the housing recess 20). Starting from this point; the radial movement of the ratchet 38 is. no longer blocked since from here on, the inside 42 of the housing 15 has a larger diameter.
Therefore, after this, the ratchet 38 can slide past one tooth of the pushrod 14 into the next tooth notch, as shown in Fig. 3, and can engage there.
-11- L~ ~ y ~ ~ / 2 Since the cocking spring 1 1 is disposed between the distal end of the housing 15 and a shoulder 44 (Fig. 1 ~ of the drive mechanism 35, it is compressed when the drive mechanism 35 is displaced in the distal direction, and when the cocked position is reached, a detent mechanism 46, located on drive mechanism 35, engages in the recess 48 of the housing 15 and locks the drive mechanism 35 in the position of Fig. 3. This is the position before an injection. Here, the needle 22 is disposed in the housing so that it cannot be seen by the user, which relieves him of pre-injection anxiety. The retainer 17 is retained in this position in the housing 15 10 because it is connected to the pushrod 14 by the ratchet 27, and because for its part, pushrod 14 is secured against undesired axial movements relative to the drive mechanism 35 by means of ratchet 38, which rests against pushrod 14 with elastic bias. For its part, the drive mechanism 35 is locked into housing 15 by detent element 46.
15 Fig. 7 shows one possible design of the detent element 46, which is disposed here so that it can move radially in a recess 50 of the drive mechanism 35 and is acted upon in the radially outward direction by a cocking spring 52. Figs. 8 and 9 show another preferred embodiment of this detent element and this is described below.
In the position of Fig. 3, if an injection is triggered by pressing on the detent element 46 in the direction of the arrow 54, then the spring 1 1 slides the drive mechanism 35 in the proximal direction. This movement is transmitted directly to the pushrod 14 via the ratchet 40 and for its part, the pushrod 14 transmits this movement directly to the retainer 17 and the container 12 via the ratchet 27, which cannot move out of the way in a radially outward direction, so that the container 12 is displaced in the proximal direction and the needle 22 is inserted, as shown in Fig. 4.
Fig. 4 also shows that even when the container 12 reaches its proximal end position, where its projection 18 abuts against the proximal end 20p of the recess 20, the ratchet 27 comes into the range of the recess 20 on the inside of the housing 15, and consequently can now move out of the way in a radially outward direction, i.e. the pushrod 14 can continue its proximal movement and now moves the plunger 23 in the container 12 in the proximal direction by one tooth space of the pushrod 14, which expels a corresponding quantity of fluid from the container 12 and injects it. For example, the pushrod 14 may have 10 or~14 teeth,.depending on the size of the desired injection dosage:
When after several. injections, all of the fluid has been .expelled from the container 12, then the injection device 10 is spent and is ready for recycling. With a pushrod 14 having 14 teeth, as shown, 14 injections with identical dosages can thus be administered and after being triggered, the process of injection occurs automatically and with excellent dosage precision since the actual injection only begins after needle 22 has -been inserted.
Figs. 8 to 13 show a preferred embodiment of the invention. Parts which are the same or function in the same manner as those in the ' preceding Figs. are usually indicated by the, same reference numerals and are then only briefly described or not described at all.
As Figs. SB and 13 show, the retainer 54 for the container 12 is formed here in two parts. It has a proximal section 56 whose proximal end has a thread 58 for screwing on a plastic part 60 attached to the needle 22, as clearly shown in Fig. 8B. On the distal end, this proximal section 56 has an enlargement 62, which has a micro-detent mechanism 64 on the inside, and into this, a distal section 66 is inserted, which also has a micro-detent on the outside of its proximal end, which engages in the micro-detent 64.
The micro-detent 64 is only schematically represented in Fig. 13 because it preferably has a very fine tooth spacing of 0.1 mm; for example, which cannot be graphically represented. The sections 56 and 66 hold 'the container 12 (with its plunger 23) in the manner shown. This is a standard container and is made by several companies.
The retainer 54 is constructed of two sections 56 and 66 for the following. reason: the container 12 and its filling quantity are subject to normal fluctuations so that in manufacture, the position of the plunger 23 relative to the retainer 54 always fluctuates betvneen certain tolerance limits.
However, it is important that even before the first injection, the proximal end of the pushrod 14 rests directly against the plunger 23 so that, as Fig. 8B shows, if there is a gap between the plunger 23 and the proximal __ ~?~i~+72 end of the pushrod 14 before the first injection, the first injection quantity is correspondingly reduced and the patient receives too little of the fluid he should have injected. Therefore, a gap of this kind has to be prevented.
Furthermore, the distal section 66 has a stop 73 on its outside, with which it abuts against the collar 70 in the distal end position that is shown in Fig. 9B. The axial movement of the retainer 54 occurs as described in Figs. 1 to 5, by position-dependent drive connection with the pushrod 14, which is described below in conjunction with Figs. 1 1 A and 1 1 B. For clarity, the total stroke S of the retainer 54 is indicated in Fig. 8A.
It should furthermore be emphasized that in the rest position, the drive mechanism 35 rests with its proximal end against the distal end of the retainer 54, and is biased against it by the cocking spring 1 1, as shown in Fig. 8A. (In Fig. 8B, this is not shown.) When adjusting the micro-detent mechanism 64 as mentioned, this makes it possible to press against the proximal section 56 of the retainer 54 in the distal direction with a force K
(on the left in Fig. 8A) and as a result, to reduce the gap between the plunger 23 and the proximal end of the pushrod 14 to zero.
Fig. 9A also shows that there is a distance D between the distal end of the retainer 54 and the proximal end of the drive mechanism 35 and this ~;~i4i2 distance D corresponds to the quantity of fluid to be injected, i.e. here, the distance between two teeth 28.
In the embodiment according to Figs. 8 to 13, the drive mechanism 35 has a pull knob 80 for compressing the spring 1 1, which knob is secured to the drive mechanism 35 in the manner shown and forms one unit with it.
(This knob is not shown in Figs. 1 to 5.) The longitudinal axis of the injection device 10 is labelled 82 in Figs.
8 and 9. It should be noted that the representations of Figs. 8 and 9 are very much enlarged, i.e. the entire device is approximately the size of an oversized fountain pen with a length of 16 to 17 cm, for example.
In the embodiment according to Figs. 8 to 13, the cocking spring 1 1 is formed as an injection molded part (coil spring) made of plastic and it is preferably unitary with a part 82, which, as shown, constitutes the distal end of the housing 15 and is connected to it in the manner shown. The spring 1 1 rests with its proximal end against the shoulder 44 of the drive mechanism 35. The latter is guided in a corresponding cylindrical recess of the part 82, as shown in Figs. 8A and 9A. Furthermore, it is guided with a radial enlargement 86 in the longitudinal groove 84 of the housing 15 so that it cannot rotate in the housing 15.
For locking in the cocked position, the drive mechanism 35 has a detent hook 94 that can be elastically deflected inward, which is formed, as shown, as being of one piece with the drive mechanism 35 and like it, is formed of a resilient plastic material. In the position of Fig. 8A, it rests elastically against the inside of the housing 15 and in the cocked position of Fig. 9A, in which the spring 1 1 is cocked, it engages in the detent recess 48 (Fig. 8A) in the housing 15.
-.. ~iyi4i2 The injection device is triggered using a clip 98 that has a projection 100 which protrudes radially inward opposite from the detent recess 48. If the clip 98, which is formed of resilient synthetic material, is pressed inward in the direction of the arrow 102 (Fig. 9A), then it presses the detent hook 94 out of the detent recess 48 (Fig. 8A) and thus triggers an injection procedure, whose course has already been described in detail in conjunction with Figs. 4 and 5. The cocking process has also already been described in detail in conjunction with Figs. 1-3.
The clip 98 is preferably formed integrally with part 82 and spring 1 1, which greatly simplifies manufacture. The drive mechanism 35, the knob 80, the pushrod 14, and the housing 15 are preferably made of the same plastic as the part 82, the spring 1 1, and the clip 98, which simplifies the recycling of the injection device to an extraordinary degree since the entire distal part of the device can be recycled as a unit. Only the receptacle 54 requires a transparent plastic so that the contents of the container 12 are externally visible (a window 105 in the housing 15 is indicated in Fig. 8B).
Therefore, the retainer 54 must be disposed of separately, just as the container 12, naturally, which is usually made of glass.
In Figs. 8, 9, and 1 1, a particular location in the injection device is labelled A for greater ease of orientation. Clearly the representations overlap in the central region.
Figs 1 1 A and 1 1 B show a section viewed in the direction of line XI-XI
in Fig. 10. In this representation, the injection device is disposed in a position according to Figs. 8A and 8B, that is, the position after an injection, i.e. the needle 22 protrudes out from the sleeve 75. As shown in Fig. 1 1 B, the housing 15 has two windows 105, 105' disposed opposite each other in the region of the cartridge 12, and since the parts of the retainer 54 are made of a transparent plastic, it is possible to see through these windows how much fluid is left in container 12.
According to Fig. 1 1 A, the distal section 66 of the retainer 54 is connected to an elastic extension 112 that runs diagonally inward in the distal direction at an angle of 10°, for example, and has a hook 1 14 on its free, distal end, which engages in a tooth space 28 of the pushrod 14. The extension 1 12 and hook 1 14 are used, in cooperation with the tooth spaces -16- ~? 7? 472 28 of the pushrod 14, as a first connecting device that acts between the pushrod 14 and the retainer 54. As shown in Fig. 12, the proximal side 1 14a of the hook 1 14 runs at an angle 1 16 to the pushrod 14, and the distal, oblique side 1 14b of the hook 1 14 runs at an angle 1 18 to the pushrod 14. Angle 1 16 is on the order of 90° and angle 1 18 is preferably on the order of 15 to 30°. An angle of 23° turned out to be favorable in tests.
When the pushrod 14 moves in the distal direction, then it pulls the hook 1 14 and with it, the retainer 54, in the distal direction, which results in the position of the retainer 54 shown in Fig. 9B. Thus here, there is a positive engagement between the pushrod 14 and the hook 1 14.
In an injection procedure, if the pushrod 14 moves in the proximal direction, then the hook 1 14, whose side 1 14b is biassed against the pushrod 14, is likewise slid in the proximal direction, i.e. there is a partially positive and partially force-connected connection between the pushrod 14 and the hook 1 14, and the retainer 54 is moved in the proximal direction until reaching the position of Fig. 1 1 B, in which section 68 of the retainer 54 rests against the collar 70 and a further proximal movement of the retainer 54 is prevented. If the pushrod 14 now moves further in the proximal direction, then the hook 1 14 slides out of the tooth space 28 and into the subsequent tooth space 28 of the pushrod 14, i.e. the first connecting device is disconnected after the needle 22 has been inserted so that now, the pushrod 14 can move the plunger 23 in the proximal direction. By means of this, the set fluid quantity is expelled from the container 12 and injected into the patient.
An elastic extension 122 protrudes obliquely inward from the drive mechanism 35 in the proximal direction and has a tip 124 on its free, proximal end fitted (adopted) to the teeth 28 that engages, as shown, in a tooth space 28 of the pushrod 14, on the left side in Fig. 1 1 A. In cooperation with the tooth spaces 28, the extension 122 and the tip 124 function as a second connecting device that acts between the drive mechanism 35 and the pushrod 14.
Here, too, the schematic representation of Fig. 12 applies with regard to the angles and the preferred values of these angles, provided that the _ -17- ~ j 7 I 4 teeth and tooth spaces 28 are formed the same on both sides of the pushrod 14. (They may have different shapes and different angles if needed.) It is a good thing if the parts 1 14, 124 rest elastically, that is, with bias, against the pushrod 14 from opposite sides since then, it is not bent toward one side.
When the pull knob 80 is moved in the distal direction, then the tip 124 follows this movement and, since it is connected to the pushrod 14 by a frictional, non-positive connection, it displaces the pushrod 14 in the distal direction. In turn, the pushrod 14 pulls the retainer 54 in the distal direction via the hook 1 14 until the abutment 73 abuts against the collar 70. The retainer 54 travels through the path S shown in Fig. 8A.
When the part 73 abuts against the collar 70, a further distal movement of the retainer 54 is blocked, as well as a further distal displacement of the pushrod 14 (by the engagement of the hook 1 14 in a tooth space 28). If the pull knob 80 is now pulled further during the cocking movement, then the force-locking, non-positive connection between the tip 124 and the tooth space 28 is released and the tip 124 slides into the subsequent tooth space 130 of the pushrod 14. In this manner, the next injection dosage is set, which corresponds to the distance between two successive teeth or tooth spaces 28. The detent hook 94 engages in the detent recess 48, as already described.
When the injection device is triggered by pressing on the clip 98 (Fig.
9A), the spring 1 1 produces a force on the tip 124 in the proximal direction, which tip is now disposed in the tooth space 130. Because of the positive fit connection, the tip 124 displaces the pushrod 14 in the proximal direction, and this movement, as previously described, is transmitted to the retainer 54 through the force-locking, non-positive connection between pushrod 14 and hook 1 14, whereby the needle 22 is inserted. After the insertion, the force-locking, non-positive connection between the pushrod 14 and the hook 1 14 is interrupted and the pushrod 14 moves the plunger 23 by the preset distance, that is, the distance between two successive teeth or tooth spaces 28, and thus causes an injection of the set quantity of fluid.
~1~~i4i'2 It should be emphasized that the hook 1 14 and the tip 124 may also be prevented from moving radially outward in particular axial positions by corresponding parts (not shown) on the inside of the housing 15, as has been explained in great detail in conjunction with Figs. 1 to 6 and can be immediately understood by one skilled in the art. However, in many cases, the embodiment described and shown in Fig. 1 1 A is also sufficient for a reliable operation, provided that the biasing forces of the extensions 1 12, 122 and the angles of teeth 28 are correctly chosen. Tests have shown that the embodiment according to Fig. 1 1 A functions in a completely satisfactory and reliable manner. In many instances, though, for safety reasons, cams will be provided in the housing, and, analogous to the embodiment according to Figs. 1 to 6, will limit the radial movements of the extensions 1 12 and 122 in certain positions and in this way, prevent malfunctions with absolute certainty.
On the inside of its proximal section, the housing part 132 guides a transparent retainer 134 (Fig. 18) for a likewise standard type of transparent cartridge 136. On the inside, the housing part 132 has guide ribs (not shown) which guide elongated projections 137, 138 of the retainer 134 in the longitudinal direction so that this retainer cannot rotate in 'the proximal section of the tubular housing part 132. This proximal section has windows 140 on both sides through which one can see how much fluid is left in the cartridge 136. Numbers 142 on these windows permit a rough estimate of -19- ~ 1 y i ~ ~2 the remaining content of the cartridge 136. Figs. 14 and 17 only show the windows 140 on one side of the tubular housing part 132; these windows are disposed symmetrically opposite from corresponding windows on the other side. A threaded sleeve 144 is attached to the tubular housing part 132, approximately in the center, and can be rotated, but cannot be displaced axially. As shown best in Fig. 15, the sleeve 144 has an internal thread 146 inside it, in the form of a fine pitch thread, and this engages with a corresponding external thread 148 of a housing part 150, whose shape is shown best in Fig. 17 and which can be shifted longitudinally in the housing part 132, for the purpose of adjusting the dosage.
According to Fig. 17, in its distal region, the tubular housing part 132 has a relatively wide longitudinal groove 152 on the bottom (with regard to Fig. 17), which has a rectangular window 154, whose shape is shown clearly in Fig. 17, approximately in the center of the housing part 132. The external thread 148' (Fig. 17) of the housing part 150 protrudes radially outward through this window 154 - through the wall of the tubular housing part 132 - so that it can engage with the internal thread 146.
As further indicated in Fig. 17 - in part with only dot-and-dash lines 156 - on its distal end, the tubular housing part 132 has a longitudinal slot 158 extending from the distal end of this housing part almost to its center.
The longitudinal slot 158 is disposed diametrically opposite the window 154 and is equal in width to it. The external thread 148 of the housing part 150 protrudes radially outward through the longitudinal slot 158 to engage with the internal thread 146 of the threaded sleeve 144.
Furthermore, the tubular housing part 132 has a viewing window 160, through which an (approximate) dosage indication 162 can be read on the housing part 150, see Fig. 15. The micro-indication of dosage, e.g.
from "0" to "19", is disposed on the threaded sleeve 144 in the form of indicia 164, and an associated indicator arrow 166 is disposed on the tubular housing part 132. The user thus adds the value 162 in the window 160, e.g. "0", to the value 164 indicated by the arrow 166, in order to obtain the current setting of the injection device 130, which is zero in Fig.
4. If he then rotates the sleeve 144 three graduation marks in the direction of the arrow 168 (Fig. 14), then he has set a dosage of three units; he only -20- ~?yi~+i2 has to change this setting if he wants to subsequently inject a different dosage.
~l~i4i'2 As best shown in Figs. 17 and 23, on its inside, the housing part 150 has an axially extending guide projection 184 serving to guide a part 186 (Fig. 16), which is described below as an advancing part because in the case of a toothed rod 188 (Fig. 16, 30, 31 ) that is guided in this advancing part, it causes an advancing movement in the proximal direction. For this, the advancing part 186 has a groove 190 (Fig. 16) that extends in the axial direction and is engaged by the guide projection 184.
On its proximal end, the housing part 150 has two diametrically opposed axial projections 192, 194, which can be elastically deflected toward each other during assembly. The upper projection 192 in Fig. 17 carries threaded section 148 and the lower section 194 carries threaded section 148'. On the upper projection 192, an elongated enlargement 196 extends, which is guided by the longitudinal slot 158 of the housing part 132 after assembly, and on the lower projection 194, an elongated enlargement 198 extends, which is guided in the groove 152 of the housing part 132 after assembly. As a result, when assembled, the housing part 150 is guided in the longitudinal direction in the housing part 132, as shown in Figs. 14 and 15, and is connected to this by virtue of the fact that the internal thread 146 of the threaded sleeve 144 engages in the external thread sections 148 and 148' of the housing part 150.
As shown in Fig. 16, in the region of its longitudinal axis, the advancing part 186 has a recess 200 with a square cross section, in which the toothed rod 188 is guided so that it can move longitudinally. This has an essentially square cross section as well, as shown in Figs. 22, 30, and 31. On its distal end, the advancing part 186 has detent projections 202 on the top and bottom, which engage in corresponding detent recesses 204 of an actuation knob 206 upon assembly. (The advancing part 186 is shown in a partial cutaway view in Fig. 15, i.e. only its distal end is visible.) The advancing part 186 has three guide parts 208, 209, 210; guide part 209 has a longitudinal groove 190, see Fig. 22. (In Fig. 16, the guide part 210 is not shown for the sake of clarity.) These guide parts slide along the inner wall 212 of the tubular housing part 132 and in this way, guide the advancing part 186 in it.
2i~i~+72 Furthermore, the advancing part 186 contains two elastic engaging members 214, 216 that are formed in the form of pliers and each have seven detent teeth 214', 216' on their free ends. These detent teeth are very small and therefore can only be shown well in the enlargement of Fig.
As shown in Fig. 25, the detent teeth 214', 216' are disposed directly opposite each other without being axially offset, while the teeth 218, 220 corresponding to them on the two sides of the toothed rod 188 that are effective here, are offset from each other by half a tooth space.
Therefore, in this representation, the detent teeth 214' engage fully and with a biasing force into the teeth 218 of the toothed rod 188 while the detent teeth 216' engage only halfway and likewise with a bias force in the teeth 220 of the toothed rod 188. (Naturally, the teeth on the toothed rod 188 could alternatively be disposed opposite each other without being axially offset, and then the axial offset would be provided in the detent teeth 214', 216', but the form represented is the preferred one.) As a result of the shape of the teeth, the toothed rod 188 can only move in the direction of the arrow 222, thus in the proximal direction, the engaging members 214, 216 then being elastically deflected radially outward. If the toothed rod 188 is moved by half a tooth space in the direction 222, then the teeth 216' engage fully with the teeth 220 of the toothed rod 188 and then the teeth 214' only engage the teeth 218 halfway. In this manner, an advance of half a tooth space can be executed, and here, a half a tooth space corresponds for example to 0.27 mm or one unit of the fluid to be injected.
In a schematic representation, Fig. 29 shows an advancing procedure of the toothed rod 222 by half a tooth space, which is indicated in the drawing as "1/2 ZT". This occurs by virtue of the fact that the advancing part 186 first is displaced in the direction of an arrow 228 in the distal direction by half a tooth space, as shown in the lower part of Fig. 29, where in a manner further described below, the toothed rod 188 is held immobile and the teeth of the advancing part 186 are sliding onwards by half a tooth space, and by virtue of the fact that the advancing part 186 then is displaced in the proximal direction in the direction of an arrow 230, ~i7i472 whereby the toothed rod 188 then is displaced in the proximal direction by half a tooth space.
Furthermore, the injection device 130 contains a retainer part 234, which is shown in three dimensional form in Fig. 17 and, in the assembled state, is connected to the retainer 134 (Fig. 18) using a detent process.
The retainer part 234 has projections 236 on its outside whose function is explained below, and it has micro-detents 238 on its outside that cooperate with corresponding micro-detents 240 (Figs. 20, 21 ) on the inside of the distal end of the retainer 134.
As can be seen best in Figs. 19 and 24, on its distal end, the retainer 234 has two plier-like, elastically deflectable engaging members 242, 244 disposed opposite each other. The substantial enlargement in Fig. 24 shows that these engaging members are each provided with seven teeth 242' or 244', which are disposed opposite each other without being axially offset, analogous to the teeth 214' and 216' in Fig. 25. (Naturally, in principle, one single tooth or even half a tooth would be enough, but a greater number of teeth is preferable.) The teeth 242' and 244' engage in corresponding teeth 246 or 248 on two opposite sides of the toothed rod 188. These teeth 246, 248 are offset in relation to each other by half a tooth space so that at all times only ~~yi412 the teeth 242' fully engage the teeth 246, as shown in Fig. 24, or only the teeth 244' fully engage the teeth 248.
Also, the teeth 242', 244', 246, and 248 are so formed that they permit the toothed rod 188 to slide only in the proximal direction (arrow 222).
The engaging members 242, 244 are so formed that they rest against the toothed rod 188 with a bias force, as indicated with arrows 250 in Fig.
24. They are formed in the shape of a collet. In the same manner, the engaging members 214, 216 of the advancing part 186 are so formed that they rest against the toothed rod 188 with bias, as shown with arrows 252 in Fig. 25.
Fig. 27 only shows the two opposite rows of teeth 218 and 220 which cooperate with the advancing part 186 and are offset in relation to each other by half a tooth space ( 1 /2 ZT), which may also be called a phase shift of 180 ° .
Fig. 28 shows only the two opposite rows of teeth 246 and 248 that are likewise offset in relation to each other by half a tooth space ( 1 /2 ZT), i.e. have a phase shift of 180°
The rows of teeth 246 and 248 cooperate with the retainer part 234 (Fig. 171 and are used to drive it analogous to the driving of part 66 in Fig.
-25- ~ ~ ~~ I ~~ / 2 Assembly First, the threaded sleeve 144 is lockingly engaged on the tubular housing part 132 in the manner previously described. Then, the part 234 is pushed into the housing part 132 from its distal end. With its detent projections 236, the part 234 slides over a corresponding inner detent bead 260 of the housing part 132. The detent projections 236 are shaped so that they permit this kind of a movement in the proximal direction, but not in the distal direction, since then, they act as abutments, as shown in Fig.
21. (In Fig. 21, the clip 176 that serves as a trigger is shown rotated by 45 °, i.e. it would not actually be visible in this sectional view.
Fig. 21 shows the cocked position for the injection of two units, corresponding to a single tooth spacing of the toothed rod 188.) Then, the housing part 150 (Fig. 17) is pushed into the tubular housing part 132. The thread 148' engages in the window 154 in the housing part 132, and by rotating the threaded sleeve 144, the housing part 150 is brought into its zero position, which is indicated in the window 160.
As a result, the housing is preassembled out of the parts 132, 144, and 150 and has the shape that can be seen in Fig. 14. This corresponds to the zero position, that is, the position for the injection of 0 units.
In Figs. 19 to 21, only the annular space 270 in which the cocking spring 262 will be disposed after installation, is shown since these drawings ~i'~i4i2 would have become very unclear if the cocking spring 262 had also been depicted there. With the exception of the cocking spring 262, all parts of the injection device 130 can be made of a suitable plastics material.
The mechanism is now assembled to a large degree, and the proximal end 188A (Fig. 29) of the toothed rod 188 is ready to actuate the plunger 272 (Figs. 19 to 21 ) of the cartridge 136. The engaging members 214, 216 of the advancing part 186 and the engaging members 242, 244 of the retainer part 234 engage each other interdigitally, as clearly shown in the sectional view in Fig. 22. This is very similar to Fig. 1 1 A, but cannot be shown in a longitudinal section. A comparison of Figs. 19 and 20 shows this engagement in each other.
The detent connection with the detent member 224 is now released by pressing on the trigger 176 whereby - through the action of the spring 262 - the toothed rod 188 assumes the position of Figs. 19 and 20, and then the cartridge 136 is inserted into the tubular housing part 132 from the proximal end until its plunger or plunger 272 rests against the proximal end 188A of the toothed rod 188. Then the retainer 134 is inserted into the housing part 132, likewise from its proximal end. By means of a corresponding force, its internal micro-detent means 240 engages the micro-detent means 238 on the retainer part 234. The force required for this engagement is measured continuously. When this force increases because the plunger 272 of the cartridge 136 comes into contact against the proximal end 188A of the toothed rod 188, the detent connection process ends since at this point, the retainer 134 is disposed in the correct position on the retainer part 234.
The device is now complete and the patient can prepare it for use by screwing a needle 276 onto a thread 278 on the proximal end of the retainer 134. With its distal end, the needle 276 penetrates a rubber membrane 280 (Fig. 18) on the proximal end of the cartridge 136. (The needle 276 should be changed after each injection. It is attached just before an injection and until then, is kept in a sterile container.) ~1~i472 _27_ Operation Before an injection, the desired dosage (e.g. 2 units) is set by rotating the threaded sleeve 144, as shown in Fig. 21. By this, the housing part 150 with its detent opening 180 is slid a corresponding distance in the distal direction relative to the housing part 132, e.g. at 2 units, by one tooth space of the toothed rod 188, corresponding for example to 0.54 mm.
Therefore, this cannot be shown graphically in Fig. 21.
During this cocking movement, the engaging members 242, 244 (Fig.
19), which act like clamping jaws and carry the retainer 134 along, will pull the needle 276 into the tubular housing part 132, see Fig. 21. The projections 236 of the retainer part 234 (seen best in Fig. 17) come to a stop against the collar 260 in the housing part 132, and when this is the case, the teeth 214', 216' slide over the teeth 218, 220 of the toothed rod 188 by the one present tooth space, and thus set the dosage; then, the detent member 224, according to Fig. 21, engages in the recess 180.
Since the toothed rod 188 still continues its movement in the proximal direction (arrow 222 in Fig. 24), it moves further in the direction of the arrow 222 in Fig. 24 by one tooth space relative to the engaging members 242, 244, (in this example, in which one tooth space has been preset as the injection dosage) whereby the corresponding quantity of fluid (2 units) is expelled from the cartridge 136 by the movement of the plunger 272. In the same way, it is also clearly possible to execute a movement of only half a tooth space, 1.5 tooth spaces, etc., and this is achieved by -2$- ~ 1 ~ i 4 % 2 virtue of the fact that the devices according to Figs. 24 and 25 are essentially identical.
Naturally, there are many possible changes and modifications within the scope of the present invention. Thus, for example, instead of the offsetting of the teeth by half a tooth space, as shown in Figs. 24 to 29, a device could be used with three rows of teeth, each of which is offset from the others by only 1 /3 of a tooth space, where each row of teeth would then be associated with a corresponding engaging member. This and other kinds of modifications are easily produced by one skilled in the art and lie within the scope of the invention.
International Classification A61M5/315, A61M5/46, A61M5/20, A61M5/32, A61M5/24
Cooperative Classification A61M5/31553, A61M5/31578, A61M5/24, A61M5/31541, A61M5/31551, A61M5/2033, A61M5/31593, A61M5/31536, A61M5/31563, A61M5/46, A61M2005/206
13 Jun 2001 EEER Examination request
11 Jul 2015 MKLA Lapsed