CA2050440A1 - Hypodermic syringe - Google Patents
Hypodermic syringeInfo
- Publication number
- CA2050440A1 CA2050440A1 CA 2050440 CA2050440A CA2050440A1 CA 2050440 A1 CA2050440 A1 CA 2050440A1 CA 2050440 CA2050440 CA 2050440 CA 2050440 A CA2050440 A CA 2050440A CA 2050440 A1 CA2050440 A1 CA 2050440A1
- Authority
- CA
- Canada
- Prior art keywords
- needle
- pump body
- plunger
- locking means
- syringe according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Infusion, Injection, And Reservoir Apparatuses (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A hypodermic syringe comprising a pump body, a plunger slidingly mounted in the pump body and a hollow needle for discharging fluid expelled from the pump body by the plunger. The syringe also comprises a first lock to detachably secure the needle to the pump body and a second lock to secure the needle to the plunger for completely drawing the needle into the pump body when the needle is detached from the pump body.
A hypodermic syringe comprising a pump body, a plunger slidingly mounted in the pump body and a hollow needle for discharging fluid expelled from the pump body by the plunger. The syringe also comprises a first lock to detachably secure the needle to the pump body and a second lock to secure the needle to the plunger for completely drawing the needle into the pump body when the needle is detached from the pump body.
Description
05044~
The present invention relates to medical devices, particularly hypodermic syringes or similar devices used to inject fluid substances through the skin while reducing risks of accidental auto-puncture once the injection is terminated.
Hypodermic syringes currently used are equipped with detachable protective casings that mu~t be removed prior to proceeding with the injection. When the needle is withdrawn from the skin, or when the user replaces the protective casing on the needle, there is potential risk of accidental auto-puncture. Several serious diseases can thus be transmitted through traces of biological liquid still present in the needle. Infections such as viral hepatitls and the acquired immunodeficiency syndrome (AIDS) are but a few examples.
The purpose of the present invention is to provide a syringe which rcduces the risks of accidental auto-puncture.
In this regard, the invention provides an engagementpermitting to attach the needle to the plunger of the syringe once the injection is terminated, thereby allowing the withdrawal of the needle within the pump body of the syringe on reciprocation of the plunger. Preferably, the -2- 2~504~0 syringe comprise~ means for blocking the needle with the pump body so as to render the syringe inoperable after the injection. This characteristic reduces the spreading of various illnesses in groups at risk such as drug addicts by making the reuse of syringes lmpossible.
In accordance with the invention, there is provided a hypodermic syringe which comprises a pump body, a plunger slidingly mounted in the pump body and a hollow needle for discharging fluid expelled from the pump body by the plunger. Preferably, the pump body is of substantially cylindrical shape and the plunger is reciprocatibly mounted within the pump body. The syringe also comprises first locking means to detachably secure lS the needle with the pump body; and second locking means adapted to secure the needle to the plunger. In operation, the plunger engages the second locklng means on a discharge stroke and after having disengaged the needle from the first locking means, the needle is withdrawn with the pump body on reciprocation of the plunger.
There is also provided a hypodermic syringe which comprises a substantially cylindrical pump body, a plunger reciprocatibly mounted with the pump body and a hollow needle for discharging fluid expelled from the pump body _3_ 205~4~0 by the plunger. The syringe further comprises first locking means for detachably integrating the needle with the pump body; and second locking means adapted to secure the needle to the plunger. In operation, the plunger engages the second locking means on a discharge stroke and after having disengaged the needle from the first locking means, the needle is withdrawn within the pump body on further reciprocation of the plunger.
In one of the preferred embodiments of the present inventlon, the hypodermic syringe has a substantially cyllndrical pump body within which a plunger is reciprocatibly mounted. A hollow needle for discharging the fluid expelled from the pump body by the plunger is integrated to the pump body through a screw-type engagement. A threaded portion of the needle extending withln the pump body is adapted to engage in a correspondingly threaded cavity in the plunger, thereby allowing to integrate the needle to the plunger. The two threadings on the needle are opposite to one another, one belng on the left and the other being on the right. This allows the needle to be unscrewed from the pump body when being screwed to the plunger.
_4_ Z05044~
When proceeding with the injection, the needle is firmly secured to the pump body of the syringe in order to avoid the untimely withdrawal of the needle during the injection. At the end of the injection, when the plunger of the syringe is towards the end of its discharge stroke, the needle is engaged on the plunger simply by rotating the plunger about its longitudinal axis. When the needle is completely screwed to the plunger, further rotation movement imparted to the plunger unscrews the needle from the pump body. Once the needle has been detached from the pump body, a simple reciprocation of the plunger withdraws the needle within the pump body which acts as a protective casing. In this withdrawn position, the needle is not parallel to a longitudinal axis of the pump body. This has the effect of offsetting the sharp end of the needle with respect to the opening on the bottom of the pump body which normally permits the passage of the needle. In this position, forward movement of the plunger wlll cause the needle to abut against the bottom of the pump body, thereby preventing the needle from coming out again. The offsetting of the needle can be obtained by making the threaded cavity on the plunger according to an axis that is obligue with respect to the longitudinal axis of the pump body ~eO5049L(~
According to a further preferred embodiment of the invention, the pump body may include a forwardly directed appendage, ~he needle being functlonally retained in the appendage to provide a first locking means. A hook-shaped element may be provided on the needle to cooperate with a receptacle on the plunger to form a second locking means.
For the purpose of this specification, the term "locking means" is not limited to a device which prevents the needle to move at all with respect to the aomponent to which it is locked. Rather, this wording should be construed to include a device which prevents the needle to move in at least one directlon.
The following is a description by way of example of certain embodiments of the invention reference being had to the accompanying drawings in which-- Figure 1 i8 a perspective vlew of a syringe according to the invention;
- Figure 2 i5 a perspective vlew of the syringe of Figure 1, after use the needle belng withdrawn into the pump body of the syringe;
-6- 2~4~
- Figure 3 is an enlarged section of one embodiment of the syringe of the invention, illustrating the interaction between the plunger and the needle;
- Figure 4 is a section view of the syringe according to Figure 3, illustrating the plunger at the end of the discharge stroke and engaged on the needle;
- Figure 5 is a section of the syringe of Eigure 3, the needle being disengaged from the pump body of the syringe and engaged to the plunger;
- Figure 6 is a section of the syringe of Figure 3, the needle being withdrawn in the pump body;
- Figure 7 i8 a perspective view of an alternative form of appendage and plunger illustrating the plunger at the end of its discharge stroke and engaged on the needle;
- Figure 8 is a perspective view of the alternative form of plunger and appendage of Figure 7 to illustrate the interaction between the plunger and the needle;
- Figure 9 is a section of the needle of Figure 7, the needle being withdrawn in the pump body;
_7_ ~ ~S 0~ ~ ~
- Figure 10 shows an alternative form of needle.
Referring now to Figures 1, 2 and 3, the syringe according to the invention, illustrated by reference numeral 10, is provided with a substantlally cylindrical pump body 12 having a bottom 1~ on which is formed a threaded neck 16. The pump body 12 is made of relatively rigid plastic material.
In the cylindrical cavity of the pump body 12 ls slidingly mounted a plunger 18 also made of rigid plastic material. The lower extremity of the plunger 18 is covered by an elastomeric sheath 20 forming a fluid-tight seal between the plunger 18 and the internal walls of the pump body 12. On the lower extremity of the plunger 18 under the sheath 20 is formed a threaded cavity 22. The symmetry axis of the threaded cavity 22 is at a certain angle with respect to the longitudinal axis of the cylindrlcal body 12 which coincides with the symmetry axis of the threaded neck 16.
On the pump body 12 is mounted a hollow needle 24 secured to an appendage 26 screwed on the neck 16. The screw-type engagement between the needle 24 and the appendage 26 is realized by a left threading 28 on the needle and received in a correspondingly threaded cavity -8- ~05~
30 in the appendage 26. The needle 24 comprises a section extending in the cylindrical pump body 12 havlng a right threading 32 and an opening 34 located within the threaded neck 16 and communicating with the axial passage of the needle 24.
The functioning of the syringe 10 is a follows. To proceed with an injection, the syringe 10 ls used in a conventional manner, that is the patient's skin is perforated with the tip of the needle 24 and the fluid contained in the pump body 12 is expelled through the needle 24 by exerting a pressure on the plunger 18. When the plunger 18 is at the end of its course, as illustrated ln dotted lines at Figure 3, the tip of the needle 2g, which is inside the cylindrical body 12, perforates the membrane 20 and is lodged at the entrance of the threaded cavity 22. In thls posit~on, the operator rotates the plunger 18 in the direction indicated by the arrow 36 to screw the plunger 18 on the threaded tip of 32 of the needle 24. Even if the cavity 22 is slightly offset with re#pect to the needle 24, the engagement ls still possible because of the flexibility of the needle 24. Since the needle 24 is attached to the appendage 26, the operation which consists in screwing the plunger 18 on the needle 24 causes the plunger 18 to be drawn to the end of its course. Through this axial movement, the liquld remalning g ~ 04~0 in the pump body 12 cannot be expelled by the needle opening on the axis of the syringe since the needle is then inside the cavity 22. The amount of residual liquid is then expelled through the opening 34 in the neck 16 designated accordingly.
Once the plunger 18 is essentially screwed on the needle 24, the maintaining of the rotational movement will cause the needle 24 to be unscrewed from the appendage 26, threadings 28 and 32 being reversed. When the needle 24 is detached from the appendage 26, the only remaining step is to reciprocate the plunger 18 to withdraw the needle 24 wlthin the pump body 12. This is illustrated at Figures 5 and 6. Once the needle 24 is within the pump body 12, it may be observed that the needle 24 is offset with respect to the opening defined by the neck 16 and i5 thereby blocked inside the syringe. Any forward movement of the plunger 12 will cause abutment of the needle 24 against the bottom wall 14 of the cylindrical body 12, preventing the needle 24 from coming out.
Preferably, threadings 28 and 32 are quite coarse in order to effect the plunger engagement movement on the needle 24 and the disengagement of the needle 24 from the appendage 26 by rotating the plunger only once or twice to facilitate the use of the syringe.
-lo- ~0~4~
A further embodiment of the invent~on is seen in Figures 7, 8 and 9. An alternative form of appendage is generally illustrated by reference numeral 36 and ac before, the appendage is secured to the neck of a pump body 70 by means of a screw-type engagement 38. In this embodiment, a hypodermic needle 40 passes through the appendage 36. The locking member provided ln the embodiment of Figures 1 to 6 by the cooperation of the screw thread on the needle and the threaded appendage is, in this embodiment, replaced by the function between the cylindrical wall 42 of the appendage 36 and the needle 40.
The axial passage 46 provldes some friction between the appendage 36 and the needle 40. The appendage can be made of strong rubber or preferably it can be provided wi~h a rubber sleeve 100 forming at least a section of the wall 42. This rubber sleeve constitutes a fluid-tight seal around the needle to prevent fluid from leaking out the appendage 36 under the effect of pressure created by the plunger. The function locking means causes the needle 40 to be maintained in place during its introduction into the patient's skin. The needle 40 has a forwardly directed barb 48 and a second forwardly directed barb 54 for reasons to be descrlbed hereinafter.
The needle 40 also comprises a forwardly directed barb 48. Thiæ barb 48 will act as a needle motion limiting element when coming into contact with the forward wall 50 of a cavity 52 defined in the appendage 36 to receive the forwardly directed barb 48.
The needle 40 ~see also Figure 9) also comprises a second forwardly directed barb 54 that will cooperate with the plunger, generally designated as numeral 56, to withdraw the needle 40 within the pump body 70.
The alternative form of plunger head, generally designated as numeral 56, is as before made of rigid plastlc material. As in the embodiment of Figures 1 to 6, the leading end of the plunger head 56 is covered by an elastomeric leading face sheath 58 forming a fluid-tight seal between the plunger 56 and the wall 72 of the pump body 60. On the leading end of the plunger head 56, under the sheath 58, is formed frustro-conical recess 60, communicating by means of a cylindrlcal passage Ç6 to the leading end of the plunger head 56. The frustro-conical recess 60 has two annular shoulders 62 and 64. In this embodiment, the frustro-conical recess 60 and the barb 54 combine to form the second locking means.
~2~5~)49L{~
To proceed with an injection, the patient's skin is perforated with the tip of the needle 40. The friction between the needle 40 and the wall 42 of the appendage 36 allows the needle 40 to be maintained ln posltion when introduced ln the patient's skin. A~ before, the plunger 56 is pushed forward to administer the proper medication dosage. As the head of the plunger 56 approaches the end of its travel, the rear tip of the needle 40 which is inside the cylindrical body perforates the leading face sheath 58 and is lodged at the entrance of the passage 66 leading to the recess 60. Although the needle 40 has pierced the leading face sheath 58, medication is still forced by forward movement of the plunger because the medication enters the receptacle and ls forced through the rear tip of the syringe until the needle 40 hits the back wall 68 of the receptacle 60 at the end of the discharge stroke. The syringe has been previously callbrated to accommodate this situation.
The forwardly directed barb 48 located on the needle 40, by abutting on appendage wall 50, prevents any forward movement of the needle that could result from the pressure exerted by the plunger on the needle.
The injection now having been administered, the hypodermic needle 40 is removed from ~he patient's body.
To render the hypodermic needle unusable, the plunger 56 is now withdrawn and the second locking means comprising the barb 54 in the recess 60 is operated, the barb 54 engaging the shoulder 64. The withdrawal of the plunger 56 overcomes the friction of the first locking means and disengages the needle 40 from the appendage 36. Further withdrawal of the plunger 56 pulls the needle 40 within the pump body 70 as shown in Figure 9.
Since the diameter oE the passage 66 is larger than the diameter of the needle 40, t,he needle 40 will be offset with respect to the longitudinal axls of the 1.5 syrlnge as shown in Flgure 9. Any ~Eorward movement of the plunger 56 wlll cause abutment of the needle 40 agalnst the bottom wall 74 of the cylindrical body 70 and thereby prevent the needle 40 from being reintroduced in the appendage 36.
As shown 1n Eigure 10, the needle motion limiting element can be a portion of enlarged diameter 76 on the needle 40 and the barb 54 replaced by a hook 78 formed by bending the needle, care being taken not to close the needle passage at the sharp bend which would render the needle inoperative.
~504~(~
The description of the preferred embodiment provided above should not be interpreted as limiting the scope of the present invention since the syringe may be modifled without departing from the essence of the invention, which is set forth in the appended claims.
The present invention relates to medical devices, particularly hypodermic syringes or similar devices used to inject fluid substances through the skin while reducing risks of accidental auto-puncture once the injection is terminated.
Hypodermic syringes currently used are equipped with detachable protective casings that mu~t be removed prior to proceeding with the injection. When the needle is withdrawn from the skin, or when the user replaces the protective casing on the needle, there is potential risk of accidental auto-puncture. Several serious diseases can thus be transmitted through traces of biological liquid still present in the needle. Infections such as viral hepatitls and the acquired immunodeficiency syndrome (AIDS) are but a few examples.
The purpose of the present invention is to provide a syringe which rcduces the risks of accidental auto-puncture.
In this regard, the invention provides an engagementpermitting to attach the needle to the plunger of the syringe once the injection is terminated, thereby allowing the withdrawal of the needle within the pump body of the syringe on reciprocation of the plunger. Preferably, the -2- 2~504~0 syringe comprise~ means for blocking the needle with the pump body so as to render the syringe inoperable after the injection. This characteristic reduces the spreading of various illnesses in groups at risk such as drug addicts by making the reuse of syringes lmpossible.
In accordance with the invention, there is provided a hypodermic syringe which comprises a pump body, a plunger slidingly mounted in the pump body and a hollow needle for discharging fluid expelled from the pump body by the plunger. Preferably, the pump body is of substantially cylindrical shape and the plunger is reciprocatibly mounted within the pump body. The syringe also comprises first locking means to detachably secure lS the needle with the pump body; and second locking means adapted to secure the needle to the plunger. In operation, the plunger engages the second locklng means on a discharge stroke and after having disengaged the needle from the first locking means, the needle is withdrawn with the pump body on reciprocation of the plunger.
There is also provided a hypodermic syringe which comprises a substantially cylindrical pump body, a plunger reciprocatibly mounted with the pump body and a hollow needle for discharging fluid expelled from the pump body _3_ 205~4~0 by the plunger. The syringe further comprises first locking means for detachably integrating the needle with the pump body; and second locking means adapted to secure the needle to the plunger. In operation, the plunger engages the second locking means on a discharge stroke and after having disengaged the needle from the first locking means, the needle is withdrawn within the pump body on further reciprocation of the plunger.
In one of the preferred embodiments of the present inventlon, the hypodermic syringe has a substantially cyllndrical pump body within which a plunger is reciprocatibly mounted. A hollow needle for discharging the fluid expelled from the pump body by the plunger is integrated to the pump body through a screw-type engagement. A threaded portion of the needle extending withln the pump body is adapted to engage in a correspondingly threaded cavity in the plunger, thereby allowing to integrate the needle to the plunger. The two threadings on the needle are opposite to one another, one belng on the left and the other being on the right. This allows the needle to be unscrewed from the pump body when being screwed to the plunger.
_4_ Z05044~
When proceeding with the injection, the needle is firmly secured to the pump body of the syringe in order to avoid the untimely withdrawal of the needle during the injection. At the end of the injection, when the plunger of the syringe is towards the end of its discharge stroke, the needle is engaged on the plunger simply by rotating the plunger about its longitudinal axis. When the needle is completely screwed to the plunger, further rotation movement imparted to the plunger unscrews the needle from the pump body. Once the needle has been detached from the pump body, a simple reciprocation of the plunger withdraws the needle within the pump body which acts as a protective casing. In this withdrawn position, the needle is not parallel to a longitudinal axis of the pump body. This has the effect of offsetting the sharp end of the needle with respect to the opening on the bottom of the pump body which normally permits the passage of the needle. In this position, forward movement of the plunger wlll cause the needle to abut against the bottom of the pump body, thereby preventing the needle from coming out again. The offsetting of the needle can be obtained by making the threaded cavity on the plunger according to an axis that is obligue with respect to the longitudinal axis of the pump body ~eO5049L(~
According to a further preferred embodiment of the invention, the pump body may include a forwardly directed appendage, ~he needle being functlonally retained in the appendage to provide a first locking means. A hook-shaped element may be provided on the needle to cooperate with a receptacle on the plunger to form a second locking means.
For the purpose of this specification, the term "locking means" is not limited to a device which prevents the needle to move at all with respect to the aomponent to which it is locked. Rather, this wording should be construed to include a device which prevents the needle to move in at least one directlon.
The following is a description by way of example of certain embodiments of the invention reference being had to the accompanying drawings in which-- Figure 1 i8 a perspective vlew of a syringe according to the invention;
- Figure 2 i5 a perspective vlew of the syringe of Figure 1, after use the needle belng withdrawn into the pump body of the syringe;
-6- 2~4~
- Figure 3 is an enlarged section of one embodiment of the syringe of the invention, illustrating the interaction between the plunger and the needle;
- Figure 4 is a section view of the syringe according to Figure 3, illustrating the plunger at the end of the discharge stroke and engaged on the needle;
- Figure 5 is a section of the syringe of Eigure 3, the needle being disengaged from the pump body of the syringe and engaged to the plunger;
- Figure 6 is a section of the syringe of Figure 3, the needle being withdrawn in the pump body;
- Figure 7 i8 a perspective view of an alternative form of appendage and plunger illustrating the plunger at the end of its discharge stroke and engaged on the needle;
- Figure 8 is a perspective view of the alternative form of plunger and appendage of Figure 7 to illustrate the interaction between the plunger and the needle;
- Figure 9 is a section of the needle of Figure 7, the needle being withdrawn in the pump body;
_7_ ~ ~S 0~ ~ ~
- Figure 10 shows an alternative form of needle.
Referring now to Figures 1, 2 and 3, the syringe according to the invention, illustrated by reference numeral 10, is provided with a substantlally cylindrical pump body 12 having a bottom 1~ on which is formed a threaded neck 16. The pump body 12 is made of relatively rigid plastic material.
In the cylindrical cavity of the pump body 12 ls slidingly mounted a plunger 18 also made of rigid plastic material. The lower extremity of the plunger 18 is covered by an elastomeric sheath 20 forming a fluid-tight seal between the plunger 18 and the internal walls of the pump body 12. On the lower extremity of the plunger 18 under the sheath 20 is formed a threaded cavity 22. The symmetry axis of the threaded cavity 22 is at a certain angle with respect to the longitudinal axis of the cylindrlcal body 12 which coincides with the symmetry axis of the threaded neck 16.
On the pump body 12 is mounted a hollow needle 24 secured to an appendage 26 screwed on the neck 16. The screw-type engagement between the needle 24 and the appendage 26 is realized by a left threading 28 on the needle and received in a correspondingly threaded cavity -8- ~05~
30 in the appendage 26. The needle 24 comprises a section extending in the cylindrical pump body 12 havlng a right threading 32 and an opening 34 located within the threaded neck 16 and communicating with the axial passage of the needle 24.
The functioning of the syringe 10 is a follows. To proceed with an injection, the syringe 10 ls used in a conventional manner, that is the patient's skin is perforated with the tip of the needle 24 and the fluid contained in the pump body 12 is expelled through the needle 24 by exerting a pressure on the plunger 18. When the plunger 18 is at the end of its course, as illustrated ln dotted lines at Figure 3, the tip of the needle 2g, which is inside the cylindrical body 12, perforates the membrane 20 and is lodged at the entrance of the threaded cavity 22. In thls posit~on, the operator rotates the plunger 18 in the direction indicated by the arrow 36 to screw the plunger 18 on the threaded tip of 32 of the needle 24. Even if the cavity 22 is slightly offset with re#pect to the needle 24, the engagement ls still possible because of the flexibility of the needle 24. Since the needle 24 is attached to the appendage 26, the operation which consists in screwing the plunger 18 on the needle 24 causes the plunger 18 to be drawn to the end of its course. Through this axial movement, the liquld remalning g ~ 04~0 in the pump body 12 cannot be expelled by the needle opening on the axis of the syringe since the needle is then inside the cavity 22. The amount of residual liquid is then expelled through the opening 34 in the neck 16 designated accordingly.
Once the plunger 18 is essentially screwed on the needle 24, the maintaining of the rotational movement will cause the needle 24 to be unscrewed from the appendage 26, threadings 28 and 32 being reversed. When the needle 24 is detached from the appendage 26, the only remaining step is to reciprocate the plunger 18 to withdraw the needle 24 wlthin the pump body 12. This is illustrated at Figures 5 and 6. Once the needle 24 is within the pump body 12, it may be observed that the needle 24 is offset with respect to the opening defined by the neck 16 and i5 thereby blocked inside the syringe. Any forward movement of the plunger 12 will cause abutment of the needle 24 against the bottom wall 14 of the cylindrical body 12, preventing the needle 24 from coming out.
Preferably, threadings 28 and 32 are quite coarse in order to effect the plunger engagement movement on the needle 24 and the disengagement of the needle 24 from the appendage 26 by rotating the plunger only once or twice to facilitate the use of the syringe.
-lo- ~0~4~
A further embodiment of the invent~on is seen in Figures 7, 8 and 9. An alternative form of appendage is generally illustrated by reference numeral 36 and ac before, the appendage is secured to the neck of a pump body 70 by means of a screw-type engagement 38. In this embodiment, a hypodermic needle 40 passes through the appendage 36. The locking member provided ln the embodiment of Figures 1 to 6 by the cooperation of the screw thread on the needle and the threaded appendage is, in this embodiment, replaced by the function between the cylindrical wall 42 of the appendage 36 and the needle 40.
The axial passage 46 provldes some friction between the appendage 36 and the needle 40. The appendage can be made of strong rubber or preferably it can be provided wi~h a rubber sleeve 100 forming at least a section of the wall 42. This rubber sleeve constitutes a fluid-tight seal around the needle to prevent fluid from leaking out the appendage 36 under the effect of pressure created by the plunger. The function locking means causes the needle 40 to be maintained in place during its introduction into the patient's skin. The needle 40 has a forwardly directed barb 48 and a second forwardly directed barb 54 for reasons to be descrlbed hereinafter.
The needle 40 also comprises a forwardly directed barb 48. Thiæ barb 48 will act as a needle motion limiting element when coming into contact with the forward wall 50 of a cavity 52 defined in the appendage 36 to receive the forwardly directed barb 48.
The needle 40 ~see also Figure 9) also comprises a second forwardly directed barb 54 that will cooperate with the plunger, generally designated as numeral 56, to withdraw the needle 40 within the pump body 70.
The alternative form of plunger head, generally designated as numeral 56, is as before made of rigid plastlc material. As in the embodiment of Figures 1 to 6, the leading end of the plunger head 56 is covered by an elastomeric leading face sheath 58 forming a fluid-tight seal between the plunger 56 and the wall 72 of the pump body 60. On the leading end of the plunger head 56, under the sheath 58, is formed frustro-conical recess 60, communicating by means of a cylindrlcal passage Ç6 to the leading end of the plunger head 56. The frustro-conical recess 60 has two annular shoulders 62 and 64. In this embodiment, the frustro-conical recess 60 and the barb 54 combine to form the second locking means.
~2~5~)49L{~
To proceed with an injection, the patient's skin is perforated with the tip of the needle 40. The friction between the needle 40 and the wall 42 of the appendage 36 allows the needle 40 to be maintained ln posltion when introduced ln the patient's skin. A~ before, the plunger 56 is pushed forward to administer the proper medication dosage. As the head of the plunger 56 approaches the end of its travel, the rear tip of the needle 40 which is inside the cylindrical body perforates the leading face sheath 58 and is lodged at the entrance of the passage 66 leading to the recess 60. Although the needle 40 has pierced the leading face sheath 58, medication is still forced by forward movement of the plunger because the medication enters the receptacle and ls forced through the rear tip of the syringe until the needle 40 hits the back wall 68 of the receptacle 60 at the end of the discharge stroke. The syringe has been previously callbrated to accommodate this situation.
The forwardly directed barb 48 located on the needle 40, by abutting on appendage wall 50, prevents any forward movement of the needle that could result from the pressure exerted by the plunger on the needle.
The injection now having been administered, the hypodermic needle 40 is removed from ~he patient's body.
To render the hypodermic needle unusable, the plunger 56 is now withdrawn and the second locking means comprising the barb 54 in the recess 60 is operated, the barb 54 engaging the shoulder 64. The withdrawal of the plunger 56 overcomes the friction of the first locking means and disengages the needle 40 from the appendage 36. Further withdrawal of the plunger 56 pulls the needle 40 within the pump body 70 as shown in Figure 9.
Since the diameter oE the passage 66 is larger than the diameter of the needle 40, t,he needle 40 will be offset with respect to the longitudinal axls of the 1.5 syrlnge as shown in Flgure 9. Any ~Eorward movement of the plunger 56 wlll cause abutment of the needle 40 agalnst the bottom wall 74 of the cylindrical body 70 and thereby prevent the needle 40 from being reintroduced in the appendage 36.
As shown 1n Eigure 10, the needle motion limiting element can be a portion of enlarged diameter 76 on the needle 40 and the barb 54 replaced by a hook 78 formed by bending the needle, care being taken not to close the needle passage at the sharp bend which would render the needle inoperative.
~504~(~
The description of the preferred embodiment provided above should not be interpreted as limiting the scope of the present invention since the syringe may be modifled without departing from the essence of the invention, which is set forth in the appended claims.
Claims (23)
1. A hypodermic syringe comprising:
- a pump body;
- a plunger slidingly mounted in said pump body;
- a hollow needle;
- first locking means to detachably secure said needle to said pump body; and - second locking means to secure said needle to said plunger and to completely draw said needle into said pump body when said needle is detached from said pump body.
- a pump body;
- a plunger slidingly mounted in said pump body;
- a hollow needle;
- first locking means to detachably secure said needle to said pump body; and - second locking means to secure said needle to said plunger and to completely draw said needle into said pump body when said needle is detached from said pump body.
2. A syringe according to claim 1, wherein said pump body includes a forwardly directed pump body appendage, said needle being initially detachably mounted in said appendage.
3. A syringe according to claim 1, wherein said needle is disengaged from said first locking means by rotation of said plunger about its longitudinal axis after said discharge stroke and prior to said reciprocation.
4. A syringe according to claim 1, characterized in that said first locking means is a screw-type engagement.
5. A syringe according to claim 4, characterized in that said second locking means is a screw-type engagement.
6. A syringe according to claim 5, characterized in that said screw-type engagements of said first and second locking means have opposite threadings.
7. A syringe according to claim 5, wherein said screw-type engagement has a coarse thread.
8. A syringe according to claim 1, comprising means for permanently retaining said needle in said pump body after it has been withdrawn therein when said needle is received in said pump body.
9. A syringe according to claim 1, characterized in that said needle is offset from the longitudinal axis of said pump body when said needle is entirely within said pump body.
10. A syringe according to claim 9, characterized in that the offset condition is provided by making said second locking means eccentric to a longitudinal axis of said pump body.
11. A hypodermic syringe comprising:
- a substantially cylindrical pump body;
- a plunger reciprocatibly mounted within said pump body;
- a hollow needle for discharging fluid expelled from said pump body by said plunger;
- first locking means for detachably integrating said needle with said pump body; and - second locking means adapted to secure said needle to said plunger, said plunger in operation engaging said second locking means on a discharge stroke and after disengaging said needle from said first locking means, withdrawing said needle within said pump body on further reciprocation of said plunger.
- a substantially cylindrical pump body;
- a plunger reciprocatibly mounted within said pump body;
- a hollow needle for discharging fluid expelled from said pump body by said plunger;
- first locking means for detachably integrating said needle with said pump body; and - second locking means adapted to secure said needle to said plunger, said plunger in operation engaging said second locking means on a discharge stroke and after disengaging said needle from said first locking means, withdrawing said needle within said pump body on further reciprocation of said plunger.
12. A syringe according to claim 1, wherein said needle is disengaged by initial reciprocation of said plunger.
13. A hypodermic syringe according to claim 1, wherein said pump body includes a forwardly directed appendage, said needle being mounted in said appendage.
14. A hypodermic syringe according to claim 13, wherein said first locking means include an axial passage in said appendage providing a frictional engagement between said appendage and said needle.
15. A hypodermic syringe according to claim 11, wherein said needle includes a needle motion limiting element.
16. A hypodermic syringe according to claim 15, wherein said element on said needle is a portion of enlarged diameter on said needle.
17. A hypodermic syringe according to claim 15, wherein said element on said needle is a forwardly directed barb.
18. A hypodermic syringe according to claim 11, wherein said second locking means comprises a locking member comprising a hook-shaped element adapted to cooperate with a receptacle in said plunger.
19. A hypodermic syringe according to claim 18, wherein said hook-shaped element is a barb.
20. A hypodermic syringe according to claim 11, wherein said plunger includes a leading face.
21. A hypodermic syringe comprising:
- a substantially cylindrical pump body;
- a plunger reciprocatibly mounted within said pump body;
- a hollow needle for discharging fluid expelled from said pump body by said plunger;
- first locking means for detachably integrating said needle with said pump body; and - second locking means adapted to secure said needle to said plunger, said plunger in operation engaging said second locking means on a discharge stroke and after disengaging said needle from said first locking means, withdrawing said needle within said pump body on reciprocation of said plunger.
- a substantially cylindrical pump body;
- a plunger reciprocatibly mounted within said pump body;
- a hollow needle for discharging fluid expelled from said pump body by said plunger;
- first locking means for detachably integrating said needle with said pump body; and - second locking means adapted to secure said needle to said plunger, said plunger in operation engaging said second locking means on a discharge stroke and after disengaging said needle from said first locking means, withdrawing said needle within said pump body on reciprocation of said plunger.
22. A hypodermic syringe, comprising:
- a pump body;
- a plunger reciprocatibly mounted within said pump body;
- a hollow needle for discharging fluid expelled from said pump body by said plunger;
- abutment means on said needle, cooperating with said pump body to prevent said needle from being pulled out of said pump body; and - locking means to secure said needle to said plunger when said plunger is on a discharge stroke, said locking means causing said needle to be withdrawn within said pump body on reciprocation of said plunger.
- a pump body;
- a plunger reciprocatibly mounted within said pump body;
- a hollow needle for discharging fluid expelled from said pump body by said plunger;
- abutment means on said needle, cooperating with said pump body to prevent said needle from being pulled out of said pump body; and - locking means to secure said needle to said plunger when said plunger is on a discharge stroke, said locking means causing said needle to be withdrawn within said pump body on reciprocation of said plunger.
23. A hypodermic syringe as defined in claim 22, comprising a fluid-tight sliding engagement between said needle and said pump body permitting said needle to be withdrawn within said pump body by said locking means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64399091A | 1991-01-22 | 1991-01-22 | |
| US07/643,990 | 1991-01-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2050440A1 true CA2050440A1 (en) | 1992-07-23 |
Family
ID=24582988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2050440 Abandoned CA2050440A1 (en) | 1991-01-22 | 1991-08-30 | Hypodermic syringe |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2050440A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11413401B2 (en) | 2019-02-13 | 2022-08-16 | Qatar University | Plunger restricted safety syringe |
-
1991
- 1991-08-30 CA CA 2050440 patent/CA2050440A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11413401B2 (en) | 2019-02-13 | 2022-08-16 | Qatar University | Plunger restricted safety syringe |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4650468A (en) | Medical syringe | |
| US4927414A (en) | Syringe with safety retracting needle | |
| US6171285B1 (en) | Retractable syringe | |
| CA2490315C (en) | Medical needle assemblies | |
| US5171300A (en) | Disposable hypodermic syringe | |
| CA2321441C (en) | Retracting needle syringe | |
| CA2093386C (en) | Safety needle syringe | |
| US4813936A (en) | Retracting hypodermic needle | |
| US5273543A (en) | Safety needle syringe | |
| US4699614A (en) | Non-reusable syringe | |
| US7458962B2 (en) | Retractable needle medical device for injecting fluid from a pre-filled cartridge | |
| EP1551482B1 (en) | Single use syringe having safety shield | |
| EP0895481B1 (en) | Injection needle | |
| US4675005A (en) | Retractable disposable syringe | |
| US5000738A (en) | Protective syringe with frangible barrel | |
| US6626863B1 (en) | Safety syringe | |
| JPH05504691A (en) | Syringe with replaceable and retractable needle platform | |
| GB2445228A (en) | Cartridge syringe with viewing windows | |
| CA2121233C (en) | An injection device | |
| JP2014502882A (en) | Automatic syringe | |
| JPH04500621A (en) | hypodermic syringe | |
| JPH06504217A (en) | plastic syringe | |
| US20060084913A1 (en) | Safety syringe with needle orienting mechanism | |
| CA2050440A1 (en) | Hypodermic syringe | |
| CN213852528U (en) | Safety disposable syringe |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |