DK154472B

DK154472B - INJECTION PROJECT

Info

Publication number: DK154472B
Application number: DK405374AA
Authority: DK
Inventors: Stanley Jay Sarnoff; George Burnham Calkins
Original assignee: Duphar Int Res
Priority date: 1973-08-01
Filing date: 1974-07-29
Publication date: 1988-11-21
Also published as: AU7185474A; NL160725B; JPS5892950U; ATA621774A; HK10278A; DE2436000A1; NL7410081A; IT1016724B; PH11120A; BE818268A; GB1449986A; SE7409781L; ES428770A1; CH573753A5; AT353944B; DE2436000C2; AR202226A1; IN140663B; FR2239258B1; IT1016723B

Description

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Opfindelsen angår en injektionssprøjte til subkutan indsprøjtning og omfattende dels en patron, der inkluderer en ampul med påsat kanyle, dels en patronholder, hvori patronen er forskydeligt monteret, 5 hvilken holder har en åben ende og en ende, der rummer kanylen, og som er lukket til,bortset fra en åbning for passage af kanylen, når sprøjten aktiveres, hvilken ampul omfatter en cylindrisk beholder med et forskydeligt stempel, hvilken beholder er åben i den ene ende og i 10 den anden ende har monteringsmidler til kanylen, dels et flydende medikament i beholderen mellem stemplet og kanylen, dels drivorganer virkningsmæssigt tilknyttet patronen til bevægelse af denne fremad i kanylens retning og til injicering af den i ampullen opbevarede 15 væske, dels organer til styring af drivorganernes aktivering.The invention relates to a syringe for subcutaneous injection and comprising partly a cartridge comprising an ampoule with attached cannula, partly a cartridge holder in which the cartridge is slidably mounted, which holder has an open end and an end which holds the cannula and which is closed except for an opening for passage of the cannula when the syringe is activated, which ampoule comprises a cylindrical container with a slidable piston, which container is open at one end and at the other end has mounting means for the cannula, partly a liquid medicament in the container between the plunger and the cannula, partly drive means operatively connected to the cartridge for moving it forward in the direction of the cannula and for injecting the liquid stored in the ampoule, partly means for controlling the activation of the drive means.

Injektionssprøjter af nævnte type er navnlig blevet udviklet for anvendelse af personer, som på et tidspunkt, som ikke kendes på forhånd, skal indgive en 20 indsprøjtning i deres egen krop. Det drejer sig. f.eks. om personer, som umiddelbart efter en hjerteinfarkt har en stor risiko for hjertesvigt eller soldater, der er blevet udsat for en krigsgas fra fjenden, f.eks. en nervegas. Det er derfor klart, at automatiske injek-25 tionssprøjter skal pålægges strenge krav med hensyn til deres pålidelighed. Sådanne sprøjter opbevares sædvanligvis i mange år af gangen og kan desuden bæres af den potentielle bruger i lange tidsperioder under forskellige forhold. På trods af dette skal pålideligheden af 30 injektionssprøjten forblive tilstrækkelig stor på det kritiske tidspunkt, hvor injektionen kræves. På dette kritiske tidspunkt kan endog brugerens liv afhænge af injektionssprøjtens beredthed. Enhver risiko for, at glasampullen før afgivelse af det flydende medikament 35 går i stykker, skal derfor undgås. Faktisk er der en stor risiko for ved anvendelse af den inj ektionssprøj - 2Syringes of the said type have in particular been developed for use by persons who, at a time not known in advance, are to administer an injection into their own body. It's about. for example. about persons who immediately after a heart attack have a high risk of heart failure or soldiers who have been exposed to a war gas from the enemy, e.g. a nerve gas. It is therefore clear that automatic syringes must be subject to strict requirements regarding their reliability. Such syringes are usually stored for many years at a time and can also be worn by the potential user for long periods of time under various conditions. Despite this, the reliability of the syringe must remain sufficiently high at the critical time when the injection is required. At this critical time, even the life of the user may depend on the readiness of the syringe. Therefore, any risk of the glass ampoule before dispensing the liquid drug 35 should be avoided. In fact, there is a high risk of using the syringe - 2

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te, der er beskrevet i US patent nr. 3.712.301, at glasampullen går i stykker, når patronens fremadgående bevægelse stoppes eller pludselig bremses.tea, described in U.S. Patent No. 3,712,301, that the glass ampoule breaks when the forward movement of the cartridge is stopped or suddenly braked.

Et yderligere vigtigt krav til automatiske in-5 jektionssprøjter er, at det indsprøjtede medikament skal blive aktivt så hurtigt som muligt efter brug.An additional important requirement for automatic syringes is that the injected drug must become active as soon as possible after use.

Opfindelsen giver anvisning på en inkektions-sprøjte, der opfylder nævnte krav, og med henblik herpå er injektionssprøjten ifølge opfindelsen ejendommelig 10 ved en fjedrende, kanylen dækkende skede, der omfatter en fjedrende cylinder med en lukket og en åben ende, hvilken skede er anbragt over kanylen for at holde kanylen steril, og har en sådan elasticitet, at den energi, der er oplagret i skeden, efter den er blevet sam-15 menpresset mellem patronholderen og kanylemonteringsmidlerne er større end den, som af drivorganerne udøves på stemplet, lige før det når sin slutposition, samt har en sådan længde, at der mellem skedens lukkede ende og kanylens ende er en lille afstand, samt organer 20 til forhindring af en fremadgående bevægelse af skeden, hvorved kanylen vil gennemtrænge skeden og aflevere det flydende medikament, når drivorganerne tvinger patronen fremad.The invention provides an injection syringe which meets said requirements, and for this purpose the syringe according to the invention is characterized by a resilient, needle-covering sheath comprising a resilient cylinder with a closed and an open end, which sheath is arranged above the cannula to keep the cannula sterile, and has such an elasticity that the energy stored in the vagina after it has been compressed between the cartridge holder and the cannula mounting means is greater than that exerted by the drive means on the plunger just before it reaches its end position, and has such a length that there is a small distance between the closed end of the vagina and the end of the cannula, as well as means 20 for preventing a forward movement of the vagina, whereby the cannula will penetrate the vagina and deliver the liquid medicine when the drive means force the cartridge forward.

Den fjedrende skede tjener ikke alene til at 25 holde kanylen steril, inden injektionssprøjten tages i brug, men den har også den funktion, at den fremadgående bevægelse af patronen bremses gradvis, hvorved brud på ampullen undgås, og at der under slutfasen af indsprøjtningen på grund af den fjedrende skedes virkning 30 sker en mindre tilbagetrækning af kanylen, hvilket fremmer en hurtig absorption af medikamentet i kroppen.The resilient sheath not only serves to keep the needle sterile before use of the syringe, but it also has the function of gradually slowing down the forward movement of the cartridge, thereby avoiding rupture of the ampoule and during the final phase of the injection due to of the action of the resilient sheath 30, a minor retraction of the cannula occurs, which promotes a rapid absorption of the drug into the body.

Det bemærkes, at man fra DK fremlæggelsesskrift, 133 327, der er udstedt på grundlag af DK patentansøgning 652/73, som blev indleveret 7. februar 1973, og 35 som blev almindelig tilgængelig 11. august 1973 kender en injektionssprøjte af type som angivet i indledningenIt is noted that from DK Patent Application, 133 327, issued on the basis of DK patent application 652/73, which was filed on February 7, 1973, and 35 which became generally available on August 11, 1973, a syringe of the type disclosed in the introduction

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/ 3 / til krav 1, og som har fjederorganer indskudt mellem kanyleenden af patronen og den lukkede ende af patronholderen på en sådan måde, at de virker som støddæmper, når patronen bevæges under påvirkning af drivorganer-5 ne, og trækker kanylen et begrænset stykke tilbage, efter at drivorganerne har udfoldet deres fulde virkning./ 3 / to claim 1, and having spring means interposed between the cannula end of the cartridge and the closed end of the cartridge holder in such a manner that they act as a shock absorber when the cartridge is moved under the influence of the drive means 5 and pull the cannula a limited distance back after the drive means have exerted their full effect.

Opfindelsen forklares nærmere i det følgende ved hjælp af et udførelseseksempel under henvisning til den 10 skematiske tegning, hvor fig. 1 viser i delvis gennemskåret længdesnit skeden, som den anvendes i forbindelse med kanylen, når injektionssprøjten er i beredskab, fig. 2 på tilsvarende måde som i fig. l den sam-15 menpressede skede, efter at injektionssprøjten er affyret med patronen ført helt frem og netop inden trykstykkets fremadgående bevægelse og medikamentets injektion, og fig. 3 på tilsvarende måde som i fig. 2 kanylen 20 trukket lidt tilbage fra den helt fremførte stilling i fig. 2, hvilken tilbagetrækning sker under den afsluttende fase af indføringen.The invention is explained in more detail in the following by means of an exemplary embodiment with reference to the schematic drawing, in which fig. Fig. 1 shows in partially sectioned longitudinal section the vagina as it is used in connection with the needle when the syringe is in readiness; 2 in a manner similar to FIG. 1 in the compressed sheath after the syringe has been fired with the cartridge advanced all the way forward and just before the forward movement of the pressure piece and the injection of the medicament, and fig. 3 in a manner similar to FIG. 2, the cannula 20 is slightly retracted from the fully advanced position in FIG. 2, which withdrawal occurs during the final phase of the introduction.

Injektionssprøjten omfatter en ydre cylindrisk beholder 100 med en indadrettet flange 110 i en en-25 de og en ringformet not 113 i den indre væg nær ved den anden åbne ende. Et patronelement 106 er monteret i flangeenden af den ydre beholder 100. Patronelementet 106 omfatter en patronholder 104 anbragt inde i beholderen 100 og med et smallere forparti 30 153, der danner et fremspring 154, som samvirker med en krave 112, der dannes af den ydre beholders flange 110. Det yderste forparti 156 af patronholderen 104 aftager i tykkelse til dannelse af en lille cirkulær åbning.The syringe comprises an outer cylindrical container 100 with an inwardly directed flange 110 at one end and an annular groove 113 in the inner wall near the other open end. A cartridge member 106 is mounted in the flange end of the outer container 100. The cartridge member 106 includes a cartridge holder 104 disposed within the container 100 and having a narrower front portion 153 forming a protrusion 154 which cooperates with a collar 112 formed by the outer container. container flange 110. The outer front portion 156 of the cartridge holder 104 decreases in thickness to form a small circular opening.

35 Patronen 135 inkluderer en ampulcylinder 136 med et flydende medikament 146 indeni, et stempelThe cartridge 135 includes an ampoule cylinder 136 with a liquid medicament 146 inside, a plunger

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4 148 i den ene ende og en kanyle 150 i den anden ende. På ampulcylinderen 136 findes der en forsnævring 80 med en diameter mindre end cylinderen 136's diameter og med afslutning i en udvidet ringformet 5 flange. Kanylen 150 er fastgjort til en kanyle-muffefatning 81, der igen er fastgjort til den udvidede flange på forsnævringen 80. Nærmere beskrevet omfatter muffefatningen 81 et afsnit 84 med mindre diameter, som er fastgjort til kanylen 150, og et mel-10 lemstykke 86 forbundet til en udvidelse 88. Udvidelsen 88 passer over og er fastgjort til forsnævringen 80's ringformede flange på ampulcylinde ren. Inde i ampulcylinderen 136's forsnævring mellem kanylen 150's indre ende og medikamentet kan der være 15 indskudt en væsketryksgennembrydelig hinde i hovedsagen svarende til den i US patent nr. 3.391.695 (Sarnoff) beskrevne.4,148 at one end and a cannula 150 at the other end. On the ampoule cylinder 136 there is a constriction 80 with a diameter smaller than the diameter of the cylinder 136 and terminating in an enlarged annular flange. The cannula 150 is attached to a cannula socket socket 81, which in turn is attached to the expanded flange of the constriction 80. More specifically, the socket socket 81 includes a smaller diameter section 84 attached to the cannula 150 and a spacer 86 connected. to an extension 88. The extension 88 fits over and is attached to the annular flange 80 of the constriction 80 on an ampoule cylinder. Inside the constriction of the ampoule cylinder 136 between the inner end of the cannula 150 and the drug, a liquid pressure permeable membrane substantially similar to that described in U.S. Patent No. 3,391,695 (Sarnoff) may be inserted.

Patronelementet 106 er monteret i den ydre beholder 100 med et mellemrum mellem kanylen 150 og 20 den ende af holderen 104, hvor hullet findes. Den samlede længde af ampul 135 og kanyle 150 er sådan, at den kan indeholdes helt i patronholderen 104 som vist i fig. 1.The cartridge member 106 is mounted in the outer container 100 at a space between the cannula 150 and 20 at the end of the holder 104 where the hole is located. The total length of ampoule 135 and cannula 150 is such that it can be contained entirely in the cartridge holder 104 as shown in FIG. 1.

Den ydre beholder 100 har en sådan længde, at 25 den indeholder patronelementet 106 i den ene ende og optager et drivorgan 200 i den anden ende til komplettering af injektionssprøjten. Drivorganet 200 omfatter et indre hylster 101 med en udadrettet flange 103, der ligger an mod enden af patronholderen 104, 30 når drivorganet er indsat i den ydre beholder 100.The outer container 100 is of such a length that it contains the cartridge member 106 at one end and receives a drive means 200 at the other end for completing the syringe. The drive means 200 comprises an inner sleeve 101 with an outwardly directed flange 103 which abuts against the end of the cartridge holder 104, 30 when the drive means is inserted into the outer container 100.

Den anden ende af det indre hylster 101 har en central åbning i form af et hul 120. Den bageste yderflade 122 på det indre hylster 101 er plan og vinkelret på hylsterets længdeakse af årsager, som for-35 klares senere.The other end of the inner sheath 101 has a central opening in the form of a hole 120. The rear outer surface 122 of the inner sheath 101 is flat and perpendicular to the longitudinal axis of the sheath for reasons which will be explained later.

Et trykstykke 162 passer ind i enden med den udadvendte flange af det indre hylster 101. Dette 5A push piece 162 fits into the end with the outwardly facing flange of the inner casing 101. This

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trykstykke har en cylindrisk krop 163 og et cirkulært hoved 164 med en diameter, som er større end kroppen 163' s diameter og i hovedsagen lidt mindre end diameteren for stemplet 148 i ampullen 135. I hovedet 5 164 findes en åbning, der er dimensioneret til at lig ge på linie med og svare til et gennemgående hul 166 i trykstykkets krop 163. Trykstykkets hoved 164 er udstyret med flere på omkredsen anbragte radialt rettede flige 168. Disse flige 168 har en diameter, som 10 er større end trykstykkehovedet 164's diameter, så at fligene griber ind i enden af ampulcylinderen 136. I trykstykkehovedet 164 findes der langsgående spalter 172 umiddelbart bag fligene 168. Disse spalter har en sådan størrelse, at de kan rumme fligene 168, når 15 de senere brydes af eller bøjes bagud ved brug af sprøjten. Disse spalter strækker sig i hele hovedets længde bag ved fligene.pressure piece has a cylindrical body 163 and a circular head 164 with a diameter which is larger than the diameter of the body 163 and substantially slightly smaller than the diameter of the piston 148 in the ampoule 135. In the head 5 164 there is an opening dimensioned for to lie in line with and correspond to a through hole 166 in the body 163 of the pressure piece. The head 164 of the pressure piece is provided with several radially directed tabs 168 arranged on the circumference. These tabs 168 have a diameter which is larger than the diameter of the pressure head 164, so that the tabs engage the end of the ampoule cylinder 136. In the thrust head 164 there are longitudinal slots 172 immediately behind the tabs 168. These slots are sized to accommodate the tabs 168 when they are later broken off or bent backwards using the syringe . These slits extend the entire length of the head behind the lobes.

I fig. 1 og 2 er et låsestykke 176 ført gennem hullet 166 i trykstykket 162, og det har en central 20 krop 178 med udad rettede lapper 180 på en ende passende til et ringformet bryst 182 på trykstykkehovedet 164. Den anden ende af låsestykket 176 er udstyret med fire ligeligt fordelte langsgående fjedrende palarme, der slutter i keglestubformede palhove-25 der 186. Dette låsestykke 176 holder trykstykket 162 og det indre hylster 101 i samlet stilling med en skruefjeder 138 sammentrykket imellem sig på følgende måde: en skruefjeder 138 er anbragt over trykstykkets krop 163 og ligger an mod trykstykkets hoved 30 164 i den ene ende og inderfladen af det indre hylster 101's endeflade i den anden ende. Når skruefjederen 138 sammentrykkes tilstrækkeligt, bukkes palhovederne 186 indad ved at gribe ind i periferien af endevæggens åbning 120 og passere derigennem, hvorpå palhovederne 35 186's bundflader vil lægge sig an mod den plane flade 122 på det indre hylster 101 for at tilbageholde 6In FIG. 1 and 2, a locking piece 176 is passed through the hole 166 in the pressure piece 162, and it has a central body 178 with outwardly directed flaps 180 on one end fitting to an annular chest 182 on the pressure piece head 164. The other end of the locking piece 176 is provided with four evenly spaced longitudinal resilient pawls terminating in frustoconical pawl heads 186. This locking piece 176 holds the thrust piece 162 and the inner sleeve 101 in the assembled position with a coil spring 138 compressed between them as follows: a coil spring 138 is disposed over the body of the thrust piece 163 and abuts the head of the die 304 at one end and the inner surface of the end face of the inner sleeve 101 at the other end. When the coil spring 138 is sufficiently compressed, the pawl heads 186 bend inwardly by engaging the periphery of the end wall opening 120 and passing therethrough, whereupon the bottom surfaces of the pawl heads 35 186 will abut against the planar surface 122 of the inner sheath 101 to retain 6

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trykstykket og det indre hylster i samlet tilstand med skruefjederen 138 sammentrykket mellem sig. Om ønskeligt kan den bages te plane flade 122 på det indre hylster 101 belægges med en pakskive 127 af metal, 5 i hvilket tilfælde det er fordelagtigt at tilvejebringe en føre- og holdeflange 128 til at omgive åbningen 120. Flangen 128 er udstyret med et læbeparti til at holde skiven på plads.the thrust piece and the inner sleeve in assembled condition with the coil spring 138 compressed between them. If desired, the baked flat surface 122 of the inner sleeve 101 may be coated with a packing disc 127 of metal, in which case it is advantageous to provide a guide and holding flange 128 to surround the opening 120. The flange 128 is provided with a lip portion to hold the disc in place.

Som vist i fig. 1 og 2 findes der på det indre 10 hylster 101 flere langsgående ophøjede ribber 129, der løber fra flangen 103 og i tilnærmelsesvis halvdelen af hylsterets længde. Et ydre hylster 192 passer over det indre hylster 101 og er dimensioneret til at virke sammen med ribberne 129 ved friktion.As shown in FIG. 1 and 2, there are on the inner 10 casing 101 several longitudinally raised ribs 129 extending from the flange 103 and in approximately half the length of the casing. An outer sheath 192 fits over the inner sheath 101 and is dimensioned to cooperate with the ribs 129 by friction.

15 Det ydre hylster 192 har en lukket ende 194 med en central åbning 196, hvorfra der udgår en kegiestub-formet kamflade 198, der er dimensioneret og udformet til at virke sammen med keglestubformede palhoveder 186 for at bøje disse hoveder radialt indad. Det ydre 20 hylster 192 er udstyret med en omløbende låseribbe 199, som passer ind i noten 113 i det ydre hylster 102 til fastholdelse af drivorganet 200 i det ydre hylster. Det skal bemærkes, at det ydre hylster 192 er lidt kortere end det indre hylster 101 for at sik-25 re, at der er plads mellem det ydre hylster 192's in-dervæg og flangen 103 på det indre hylster 101, så at de to hylstre kan bevæge sig i forhold til hinanden og bøje de keglestubformede palhoveder 186 indad, når sprøjten bruges.The outer sheath 192 has a closed end 194 with a central opening 196 from which a frustoconical cam surface 198 extends, dimensioned and designed to co-operate with frustoconical pawl heads 186 to bend these heads radially inwardly. The outer casing 192 is provided with a circumferential locking rib 199 which fits into the groove 113 of the outer casing 102 for retaining the drive means 200 in the outer casing. It should be noted that the outer sheath 192 is slightly shorter than the inner sheath 101 to ensure that there is space between the inner wall of the outer sheath 192 and the flange 103 of the inner sheath 101 so that the two sheaths can move relative to each other and bend the frustoconical pawl heads 186 inward when the syringe is used.

30 For at sikre, at de keglestubformede palhoveder 186 ikke tilfældigt bøjes indad, tilvejebringes der et sikringstapaggregat. Dette sikringstapaggregat omfatter et dæksel 142 med et cylindrisk rørstykke 143, der er dimensioneret til at passe over endedelen af det yd-35 re hylster 192. En sikringstap 144 strækker sig inddad fra centret af dækslet 142 ind i den åbning, 7To ensure that the frustoconical pawl heads 186 are not accidentally bent inwardly, a securing tap assembly is provided. This securing pin assembly comprises a cover 142 with a cylindrical pipe section 143 dimensioned to fit over the end portion of the outer casing 192. A securing pin 144 extends inwardly from the center of the cover 142 into the opening 7

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der dannes af de indre dele af palhovederne 186, for derved at forhindre indadgående bevægelse af palhovederne. Dækslet 142 er på indersiden forsynet med flere afstandsstykker 145 for at sikre korrekt anbrin-5 gelse af dækslet på det ydre hylster 192.formed by the inner portions of the pawl heads 186, thereby preventing inward movement of the pawl heads. The cover 142 is provided on the inside with several spacers 145 to ensure correct placement of the cover on the outer casing 192.

Som vist i fig. 1 er en fjedrende skede 250 af f.eks, gummi af farmaceutisk kvalitet anbragt over kanylen 150, så at den åbne ende af skeden passer over og rundt om kanylens fatning 84 og ligger an mod 10 skulderen 82, der dannes af fatningsdelene 84 og 86. Skeden har en sådan længde, at der er en mindre afstand mellem dens lukkede ende og kanylen 150's spids. For at sikre, at den skedebeskyttende kanyle holdes passende rettet ind efter åbningen 158, er der 15 anbragt flere ribber 157 på indersiden af et tilspidset holderparti 156, som omgiver den nævnte åbning.As shown in FIG. 1, a resilient sheath 250 of, for example, pharmaceutical grade rubber is disposed over the cannula 150 so that the open end of the sheath fits over and around the socket 84 of the cannula and abuts the shoulder 82 formed by the socket portions 84 and 86. The sheath is of such a length that there is a smaller distance between its closed end and the tip of the cannula 150. To ensure that the sheath protective cannula is kept properly aligned with the opening 158, several ribs 157 are arranged on the inside of a tapered holder portion 156 which surrounds said opening.

Enden af skeden 250 holdes således på nødvendig vis rettet ind, ved at ligge an mod den konvergerende del af ribberne 157.Thus, the end of the sheath 250 is held in the necessary manner aligned by abutting the converging portion of the ribs 157.

20 Ved aktiveringen af injektionssprøjten bevæger patronelementet 106 sig fremad, hvorved skeden 250 sammentrykkes mellem kanyleenden på patronbeholderen 104 og fatningens skulder 82, som vist i fig. 2. Kanyleskeden virker ved sin sammenpresning som en stød-25 dæmper, der gradvis optager noget af den energi, som drivfjederen 138 afgiver, medens den driver patronelementet 106 fremad. Det bemærkes, at skeden på intet tidspunkt, selv ikke når kanylen er ført helt frem, er sammentrykket i en sådan grad, at den virker som en 30 fast masse og derved i den tilstand ikke virker støddæmpende.Upon activation of the syringe, the cartridge member 106 moves forward, thereby compressing the sheath 250 between the needle end of the cartridge container 104 and the shoulder 82 of the socket, as shown in FIG. 2. When pressed, the cannula sheath acts as a shock absorber which gradually absorbs some of the energy emitted by the drive spring 138 as it propels the cartridge member 106 forward. It is noted that at no point, even when the cannula is fully advanced, is the compression to such an extent that it acts as a solid mass and thereby in that state does not act as a shock absorber.

Når kanylen 150 er ført helt frem, som vist i fig. 2, vil kanyleskeden 250 være maksimalt sammentrykket, hvorfor den største reaktionskraft i den sam-35 mentrykkede skede findes i denne stilling. Som vist i fig. 2 har patronen 135 fuldført sin bevægelse underWhen the cannula 150 is fully advanced, as shown in FIG. 2, the cannula sheath 250 will be maximally compressed, so that the greatest reaction force in the compressed sheath is found in this position. As shown in FIG. 2, the cartridge 135 has completed its movement below

Claims

A syringe for subcutaneous injection and comprising partly a cartridge (135) comprising a 25 ampoule (136) with attached needle (150), partly a cartridge holder (104), wherein the cartridge is slidably mounted, which holder has an open end and an end which houses the cannula and which is closed, except for an opening (158) for passage of the cannula when the syringe is activated, which ampoule comprises a cylindrical container with a slidable piston (148), which container is open in one end and at the other end have mounting means (81) for the cannula, partly a liquid medicament (146) in the container between the piston and the cannula, partly drive means (138) operatively connected to the cartridge for moving it forward in the direction of the cannula and for in - DK 154472 B jication of the liquid stored in the ampoule, partly. means (176) for controlling the activation of the drive means, characterized by a resilient sheath (250) covering the sheath (250), comprising a resilient cylinder with a closed and an open end, which sheath is arranged above the cannula for holding the cannula is sterile and has such an elasticity that the energy stored in the vagina after it has been compressed between the cartridge holder (104) and the cannula mounting means (81) is greater than that exerted by the drive means (138) on the piston ( 148), just before it reaches its end position, and has such a length that there is a small distance between the closed end of the sheath and the end of the cannula, and means (156) for preventing a forward movement of the sheath, whereby the cannula (150) will penetrate the sheath (250) and deliver the liquid drug (146) when the drive means (138) forces the cartridge (106) forward.

Syringe according to claim 1, characterized in that the resilient sheath (250) is of such a size that during the forward movement of the cartridge (135) it will be compressed between the mounting means (81) of the cannula and the front end (156) of the cartridge holder. (104) and act as a shock absorber.

A syringe according to claim 2, characterized in that the size of the resilient sheath (250) is such that the sheath is never completely compressed, even when the cartridge (135) is in its most advanced position. 30 35