U.S. patent application number 09/331234 was filed with the patent office on 2002-01-24 for cannula for medical syringes.
Invention is credited to BUTTGEN, HEINZ, CALLENBACH, TILO.
Application Number | 20020010421 09/331234 |
Document ID | / |
Family ID | 4250245 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020010421 |
Kind Code |
A1 |
BUTTGEN, HEINZ ; et
al. |
January 24, 2002 |
CANNULA FOR MEDICAL SYRINGES
Abstract
A cannula is retractably mounted with a needle holder (9) in a
housing (5). A switching device (7, 8) allows the hollow needle
(10) to be retracted after use into the housing (5). The needle
holder (9) secures against rotation the hollow needle (10) in the
housing (5) in a predetermined orientation. The housing (5) is
preferably provided on its outer side with markings (13) which
indicate the orientation of the hollow needle (10). The hollow
needle (9) cannot twist when it is retracted. Another advantage is
that the orientation of the needle point need not be determined
before making an injection.
Inventors: |
BUTTGEN, HEINZ; (JONA,
CH) ; CALLENBACH, TILO; (JONA, CH) |
Correspondence
Address: |
SUGHRUE MION ZINN MACPEAK & SEAS
2100 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
200373213
|
Family ID: |
4250245 |
Appl. No.: |
09/331234 |
Filed: |
June 18, 1999 |
PCT Filed: |
October 1, 1997 |
PCT NO: |
PCT/CH97/00367 |
Current U.S.
Class: |
604/110 |
Current CPC
Class: |
A61M 5/322 20130101;
A61M 5/32 20130101; A61M 5/3202 20130101; A61M 5/3232 20130101;
A61M 5/3287 20130101 |
Class at
Publication: |
604/110 |
International
Class: |
A61M 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 1996 |
CH |
3175/96 |
Claims
1. A syringe comprising a hollow needle (10), a needle holder (9)
attached to the needle (10) whereby the needle holder (9) is
located in the syringe housing (5) where it may be retracted, a
device (3) that has a switching mechanism (7, 8) by which the
hollow needle (10) may be retracted into the syringe housing (5);
whereby the switching mechanism (7, 8) may be triggered by hand at
the exterior side of the syringe housing (5) and whereby the needle
holder (9) keeps the needle (10) from turning in the syringe
housing (5) and maintains the needle (10) in a predetermined
position, characterized in that means (7) are located in the
syringe housing (5) for volume compensation during retraction of
the needle (10).
2. A syringe according to claim 1, characterized in that the
syringe housing (5) has on its exterior side a marking (13), which
shows the position of the needle (10).
3. A syringe according to claim 1, characterized in that the needle
holder (9) has a section (14) to prevent turning that has a
non-circular cross section, which is also located in a non-circular
guiding channel (15) within the syringe housing (5).
4. A syringe according to one of the claims 1 through 3,
characterized in that the means (7) for volume compensation have a
movable element (7) located within the syringe housing (5), which
may be moved to create a partial vacuum before retraction of the
needle (10).
5. A syringe according to claim 4, characterized in that the
element (7) is a shell-shaped device that is moved within the
syringe housing (5) during triggering of retraction by an actuating
mechanism (15).
6. A syringe according to one of the claims 1 through 5,
characterized in that the needle (10) has a seal around its
circumference and maintains said seal when moved
longitudinally.
7. A syringe according to claim 6, characterized in that the needle
(10) is sealed off from the movable volume-compensating means (7)
located within the syringe housing (5).
8. A syringe according to claims 1 through 7, characterized in that
retraction of the needle (10) is triggered by actuating elements
(4), which move in a circle toward the inside and against one
another.
9. A syringe according to claim 8, characterized in that the
actuating elements (4) are molded to the syringe housing (5).
10. A syringe according to claim 8 or 9, characterized in that the
actuating elements (4) move a trigger element (7) during operation,
which is located in the syringe housing (5).
11. A syringe according to claim 10, characterized in that the
trigger element (7) is moved forward in the direction of the needle
(10).
12. A syringe according to claim 10 or 11, characterized in that
the trigger element (7) operates in conjunction with a switching
box (8) that is located inside the syringe housing (5) and that the
needle holder (9) is supported by said switching box (8).
13. A syringe according to claim 12, characterized in that the
switching box (8) is mounted in a manner where it may be
rotated.
14. A syringe according to claim 12 or 13, characterized in that
the switching box (8) has projections (18) facing inwardly and
whereby said projections (18) rest against the projections (15) of
the needle holder (19), which are facing to the outside.
15. A syringe according to one of the claims 1 through 14,
characterized in that a detachable protective cap (12) is placed on
the syringe housing (5) and whereby said protective cap (12) covers
for the most part the actuating means (4) that trigger retraction
of the needle (10).
16. A syringe according to one of the claims 1 through 15,
characterized in that the syringe housing (5) has a Luer nozzle
(20).
17. A syringe according to one of the claims 1 through 15,
characterized in that the syringe is rigidly attached to a barrel
(1).
Description
[0001] The invention relates to a syringe according to the main
concept of claim 1.
[0002] A syringe of this type has been made known by the
state-of-the-art of U.S. Pat. No. 5,480,385. This syringe has the
problem that during retraction of the hollow needle, injection
solution may be released through the needle and this injection
solution might be mixed with the patient's blood.
[0003] A similar syringe has been made known by the
state-of-the-art of U.S. Pat. 5,114,404. This syringe has the
particular disadvantage in that the needle holder, together with
the hollow needle, is turned during its release. Parts of tissue
may be set free within the patient's body by turning of the needle,
which represents a considerable risk of injury. Furthermore,
another syringe was made known by EP-A-0 290 176, which also makes
retraction of the needle possible after use. However, this syringe
has a problem in that the needle may be in an arbitrary position in
relation to its longitudinal orientation. The position of the
needle point in relation to the syringe housing is hereby arbitrary
and must first be determined before each injection. Retraction of
the needle is caused here by means of a pressure spring and there
is also the danger that the needle rotates during retraction. Other
similar syringes have been made known by WO 92/16 248 and WO 92/058
18.
[0004] According to the invention, means for volume compensation
during retraction of the needle are located in the syringe housing
of a typical syringe. These means are designed, for example, in
such a manner that a partial vacuum is created before retraction.
The fluid displaced during needle retraction then compensates for
this low pressure. Thereby it can be prevented that during needle
retraction, injection solution is released through the needle,
which might be mixed with the patient's blood.
[0005] According to a preferred development of the invention, the
means for volume compensation show a movable element placed within
the syringe housing, which may be moved before needle retraction to
create a partial vacuum. According to further development of the
invention, this movable element is at the same time a trigger
element by which retraction is caused. This makes a design possible
that has very few separate components.
[0006] According to further development of the invention, means for
volume compensation during needle retraction are placed into the
syringe housing. These means are designed, for example, in such a
manner that a partial vacuum is created before retraction. The
fluid displaced by retraction of the needle compensates then for
the low pressure. Thereby it can be avoided that during needle
retraction, injection solution is released through the needle
whereby the injection solution could mix with the patient's own
blood.
[0007] According to a preferred development of the invention, the
means for volume compensation show a movable element placed within
the syringe housing, which may be moved before needle retraction to
create a partial vacuum. According to further development of the
invention, this movable element is at the same time a trigger
element by which retraction is caused. This makes a design possible
that has very few separate components.
[0008] According to further development of the invention, the
hollow needle may be moved longitudinally at the circumference and
the rear section where it has a seal. Thereby the danger of air
injection is prevented by a high degree. At the same time, problems
may be avoided during drawing of the injection solution into the
syringe and settling of air bubbles is prevented. Since only a seal
around the circumference of the needle has to be created, the
to-be-sealed area is relatively small and causes a relatively small
amount of friction during needle retraction. Additionally, the
guiding parts stabilize the needle. According to one version, the
syringe is equipped with a Luer nozzle that makes the use of the
syringe possible in conjunction with standard hypodermic needles.
However, the syringe may also be attached rigidly to a barrel.
[0009] According to further development, triggering the retraction
is possible at any time whenever the needle retraction is caused by
actuating elements, which are located inside the syringe in a
radial manner and which move against one another. These actuating
elements are preferably attached to the syringe housing. Steady
handling of the syringe is achieved by the counter movement of the
actuating elements and thereby unnecessary movement of the syringe
is avoided.
[0010] Additional advantageous characteristics are shown in the
related patent claims and the following specifications and
drawings.
[0011] One version of the invention is subsequently described in
more detail by drawings. The following is shown:
[0012] FIG. 1 A longitudinal view of an innovative syringe in its
basic position and a longitudinal view of a portion of a syringe
barrel.
[0013] FIG. 2 A longitudinal view relating to FIG. 1, without a
protective cap illustrating a retracted needle.
[0014] FIG. 3 A cross-sectional view along line III-III of FIG.
1.
[0015] FIG. 4 A cross-sectional view along line IV-IV of FIG.
1.
[0016] FIG. 5 A cross-sectional view along line V-V of FIG. 1.
[0017] FIG. 6 A cross-sectional view along line VI-VI of FIG.
2.
[0018] FIG. 7 A view of the innovative syringe without a protective
cap.
[0019] The illustrated syringe 6 shown in FIG. 1 in its basic
position is detachable and is connected to an only partially shown
barrel 1. The connection between the syringe 6 and the barrel 1
consists of a fitting 20 at the rear portion of the syringe housing
5 and a conical fitting 2 at the front portion of the barrel 1. The
connection surface between fitting 2 and 20 is conical and
corresponding to the known Luer connections. Such connections are
well known in medical syringes. The housing 5 may also be connected
rigidly with the barrel 1 according to a version not illustrated
here.
[0020] The syringe housing 5 consists of a rear housing section 23
and a front housing section 23, which are joined together at a
connection point 27 by ultrasonic welding. A detachable protective
cap 12 is placed on the front portion of the housing 5, which
prevents touching of the needle and which also covers with its rear
bell-shaped rim 35 two actuating elements 4 that retract the needle
10.
[0021] The hollow needle 10 has the usual sharp point 17 and is
firmly connected to the needle holder 9 at its middle portion by
means of an adhesive section 34. The needle holder 9 has at its
rear section several outwardly pointing teeth 19, which are resting
correspondingly against inwardly pointing teeth 18 of a switching
box 8. The force of a pressure spring 11 applies tension on the
needle holder 9 and against the abovementioned teeth 18. The needle
10 protrudes with its rear portion 36 into a longitudinal channel
25 of element 7 and is sealed at its outer movable side with an
encircling sealing lip 24. Element 7 functions as a trigger element
as well as a volume-compensating device as described in more detail
later on. Element 7 is guided by a shell-shaped fitting 28 at the
rear housing section 22 and is sealed by an encircling sealing lip
29 and is also held in place in the shown position by an
interlocking beaded rim 26.
[0022] The needle holder 9 has at its front area 14 a ratchet-like
cross section as shown in FIG. 4, and is guided by a corresponding
guiding channel 15 in the syringe housing 5 to prevent turning. The
needle holder 9 is placed into the guiding channel 15 in such a
manner that the angular ground point 17 always remains in the same
position in relation to the above-mentioned marking 13 in FIG. 7.
The position of the point 17 may thereby be seen by the marking 13
on the syringe housing.
[0023] The needle 10 and the needle holder 9 may be fully retracted
into the syringe housing 5 after use of the syringe 6. Retraction
is caused by the release of tension of the pressure spring 11. To
trigger the retraction, the switching box 8 is rotated until the
teeth 18 are located in an opening between the teeth 19 as shown in
FIG. 6. The needle holder 9 is thereby no longer blocked at the
switching box 8 and is then moved to the rear by the pressure
spring 11 into the position shown in FIG. 2. The point 17 is hereby
placed safely into a channel 38 of the housing 5. It is essential
that the retraction of the needle 10 is guided and turning is
prevented at least during the first phase of retraction. The
switching box 8 is turned when triggering the retraction, however,
the needle holder 9 is not turned. The needle holder 9 is also kept
from turning during retraction and during engagement into the
guiding channel 15. In addition, the needle 10 is supported during
retraction within the channel 38 and is also supported by the
sealing lip 24.
[0024] The switching box 8 is a part of the switching mechanism 3
and rests movably against the projection 39 in the syringe housing
5. To be able to turn, the switching box 8 has switching teeth 33
at its back side that engage into corresponding switching teeth 32
of element 7. To actually turn the switching box 8, element 7 is
moved in the direction of the arrow 40 whereby the slanted
engagement surface 41 of the teeth 32 come into contact with the
angled engagement surface 42 of the teeth 33. Turning of the
element 7 is thereby prevented by wedge-shaped blocks 43 that
protrude in a circle toward the outside. Element 7 is moved with an
actuating device that has two opposing actuating elements 4. These
actuating elements 4 have each an actuating cam 21 that is
elastically molded to an arm 45 in the forward housing section 23.
The actuating cam 21 is moved radial toward the inside to cause
retraction triggering of the needle 10 and thereby a force is
transferred onto the slanted engagement surface 16, which in turn
causes movement of element 7 in the direction of the arrow 40. The
protective cap 12 is naturally removed when operating the actuating
element. Triggering of the retraction is not possible while the
protective cap 12 is in place since the cams 21 can not be reached.
When moving the element 7 in the direction of the arrow 40, a
volume compensating space 31 is created that causes low pressure
inside the syringe housing 5. Thereby it is prevented that existing
fluid is pushed out of the needle point 17 during retraction of the
needle 10. Element 7 serves thereby as a trigger element and as a
volume compensating mechanism. At the same time, element 7 serves
to seal the needle 10 at its rear section 36 and also serves as a
guide.
[0025] Functioning of the syringe 6 will be subsequently described
in more detail.
[0026] The protective cap 12 is removed from the syringe housing 5
to fill the barrel 1 with fluid, specifically with medicine. The
point 17 of the needle 10 is submerged into the prepared fluid and
the not-illustrated common plunger of the barrel is actuated
correspondingly, whereby the fluid flows through the needle 10 and
through the sealed channel 25 within the barrel 1. As commonly done
during administration of an injection, air may be pushed out before
an injection is given by briefly lifting the plunger. Thereby it is
prevented that air bubbles are created and are eventually set free
by a position change and are then injected. When the barrel 1 is
filled with fluid, then the needle 10 is inserted in the usual
manner whereby the marking 13 shows the position of the needle
point 17. The marking 13 shows in an aseptic manner the slanted
part of the needle point 17. The fluid is then injected in a common
manner by lifting the plunger cylinder. After injection, the
above-mentioned retraction of the needle 10 is hand triggered by
firmly pressing the actuating element 4. The needle 10 is thereby
guided and moved into the position shown in FIG. 2, whereby an
unintentional touching of the needle 10 is no longer possible.
[0027] The syringe 6 is shown here in conjunction with a barrel 1.
However, conceivable is also the use of the syringe 6 for
withdrawal of blood, for example, or for in-vitro diagnostics. The
removal of the syringe 6 may not be necessary during uses of such
kind. All components, except for the needle 10 and the spring 11,
may be manufactured as plastic injection molded parts. The number
of these parts is comparatively small and assembly is suited also
for series production. The relatively small volume requirements are
also of importance, so that there is essentially little difference
between the innovative syringe 6 and the common syringe without
needle retraction.
* * * * *