U.S. patent application number 09/874844 was filed with the patent office on 2002-11-07 for injection device.
Invention is credited to Bechtold, Herbert, Gabriel, Jochen.
Application Number | 20020165500 09/874844 |
Document ID | / |
Family ID | 6519315 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020165500 |
Kind Code |
A1 |
Bechtold, Herbert ; et
al. |
November 7, 2002 |
Injection device
Abstract
The invention relates to an injection device (10) having a
housing (15) and an injector fluid container (12) whicj can move,
in relation to this housing, between a distal and proximal end
position, and also having a pushrod (14) to act on a plunger 923)
in this container (12) for the purpose of expelling fluid from the
container. A device connection (27) is provided between the pushrod
(14) and the container, this drive connection is effective in both
the proximal end position of the container (12), it is only
effective when the pushrod (14) is moved in the distal
direction.
Inventors: |
Bechtold, Herbert;
(Ehningen, DE) ; Gabriel, Jochen; (Stuttgart,
DE) |
Correspondence
Address: |
WARE FRESSOLA VAN DER SLUYS &
ADOLPHSON, LLP
BRADFORD GREEN BUILDING 5
755 MAIN STREET, P O BOX 224
MONROE
CT
06468
US
|
Family ID: |
6519315 |
Appl. No.: |
09/874844 |
Filed: |
June 5, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09874844 |
Jun 5, 2001 |
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08750289 |
Dec 2, 1996 |
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6241709 |
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Current U.S.
Class: |
604/209 |
Current CPC
Class: |
A61M 5/31551 20130101;
A61M 5/31536 20130101; A61M 5/24 20130101; A61M 5/46 20130101; A61M
5/31541 20130101; A61M 5/31563 20130101; A61M 5/31553 20130101;
A61M 5/31593 20130101; A61M 2005/206 20130101; A61M 5/31578
20130101; A61M 5/2033 20130101 |
Class at
Publication: |
604/209 |
International
Class: |
A61M 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 1994 |
DE |
P 44 18 824.2 |
May 29, 1995 |
EP |
PCT/EP95/02032 |
Claims
1. An injection device comprising a housing (15; 132, 150) and a
container (12; 136) for an injection fluid or a retainer (134, 234)
for a container of this kind, which is displaceable in relation to
this housing between a distal end position (FIGS. 2, 3, 9, 21) and
a proximal end position (FIGS. 1, 4, 5, 8, 11, 19, 20), further
comprising a pushrod (14; 188) movable relative to the housing to
expel fluid from such a container (12; 136), and comprising a first
connecting device (27; 112, 114; 242, 244, 246, 248), which is
position-dependent and/or direction-dependent, between the pushrod
(14; 188) and the container (12; 136).
2. The injection device according to claim 1, wherein the first
connecting device (27; 112, 114; 242, 244, 246, 248) is adapted
upon movement of the pushrod (14; 188) in the distal direction, to
produce a unidirectional, positive connection between the pushrod
(14; 188) and the container (12; 136) or the receptacle (134, 234)
for the container and to move the container, or the receptacle
therefor, together with the pushrod (14; 188) in the distal
direction, and which is furthermore adapted to convert a movement
of the pushrod (14; 188) in the proximal direction into a
corresponding movement of the container (12; 136) or the receptacle
(134, 234) for the container in the proximal direction until the
container (12; 136) is prevented from moving in the proximal
direction in the housing.
3. The injection device according to claim 2, wherein the
unidirectional positive connection is formed so that a stop (18,
20; 70, 73; 260) for the distal movement of the container (12; 136)
or a receptacle (134, 234) for the container also constitutes a
limit for the distal movement of the pushrod (14; 188).
4. The injection device according to one or more of claims 1 to 3,
wherein in the distal end position of the container (12; 136) or
the receptacle (134, 234) for the container, the first connecting
device (27; 112, 114; 242, 244, 246, 248) is effective in both the
proximal and the distal direction, but in the proximal end position
of the container (12; 136) or the receptacle for the container, is
only effective when the pushrod (14; 188) is moved in the distal
direction.
5. The injection device according to one or more of claims 1 to 4,
wherein a drive mechanism (35; 186) is provided for the pushrod
(14; 188) and further comprising a second connecting device (38;
122, 124; 214, 216, 218, 220) provided between the drive mechanism
(35; 186) and the pushrod (14; 188), which connecting device acts
in a position-dependent and/or direction-dependent manner.
6. The injection device according to claim 5, wherein the second
connecting device (38; 122, 124; 214, 216, 218, 220) is adapted to
produce a unidirectional positive connection in the proximal
direction between the drive mechanism (35; 186) and the pushrod
(14; 188) and to move the latter in the proximal direction,
together with the drive mechanism (35; 186), and to convert a
movement of the drive mechanism (35; 186) in the distal direction
into a corresponding movement of the pushrod (14; 188) in the
distal direction until the pushrod (14; 188) is prevented from
moving in the distal direction.
7. The injection device according to claim 5 or 6, wherein in a
proximal position range (FIG. 1) of the container (12), the second
connecting device (38) produces a connection between the drive
mechanism (35) and the pushrod (14) in both the proximal and the
distal direction.
8. The injection device according to one or more of claims 5 to 7,
wherein in a distal position range (FIGS. 2, 3, 21) of the
container (12; 136), the second connecting device (38; 214, 216,
218, 220) produces a connection between the drive mechanism (34;
186) and the pushrod (14; 188), which connection is effective in
the proximal direction and makes it possible to move the drive
mechanism (35; 186) in the distal direction relative to the pushrod
(14; 188).
9. The injection device according to one or more of claims 5 to 8,
wherein the drive mechanism (35; 186) is associated with a detent
mechanism (46; 94; 224) and a spring (11; 262), in particular a
spring made of a plastic material, which acts upon the drive
mechanism in the proximal direction and can be compressed by moving
the detent mechanism (46; 94; 224) in the distal direction, wherein
the detent mechanism engages when a predetermined cocked position
(FIGS. 3, 9, 21) is reached.
10. The injection device according to claim 9, wherein a clip (98;
176) provided on the outside of the housing (15, 150) is formed to
release the detent mechanism (94; 224) and to thus trigger an
injection process.
11. The injection device according to one or more of claims 5 to
10, wherein the drive mechanism (35; 186) is associated with an
actuating member (80; 206) which is preferably disposed in the
distal range of the device and makes it possible to slide the move
mechanism (35; 186) into its cocked position (FIGS. 9, 21).
12. The injection device according to one or more of claims 5 to
11, wherein the unidirectional positive connection between the
pushrod (14; 188) and the container (12; 136) and/or between the
drive mechanism (35; 186) and the pushrod (14; 188) is formed in
the form of a drive coupling that is unilaterally effective, in
particular in the form of a ratchet coupling.
13. The injection device according to claim 12, wherein in the
direction counter to the unidirectional positive connection, the
connecting device is formed as a frictional, non-positive
connection device and/or as a positive connection device that is
controlled in a position-dependent manner.
14. The injection device according to one or more of the preceding
claims, wherein the first connecting device comprises a member (27;
112; 242, 244) that is connected to the container (12; 136) and
formed to engage with the pushrod (14; 188).
15. The injection device according to claim 14, wherein the member
(17; 112; 242, 244) connected to the container (12; 136)
elastically engages with the pushrod (14; 188) at least in the
proximal end position of the container (12; 136).
16. The injection device according to claim 14 or 15, wherein the
container (12; 136) is associated with a retainer (17; 54; 134,
234) which is formed so that it can move relative to the housing
(15; 132, 150), the member (27; 112; 242, 244) being formed to
engage with the pushrod (14; 188) being disposed on this retainer
(17; 54; 134, 234) and being movable together with it.
17. The injection device according to one or more of the preceding
claims, wherein the second connecting device comprises a member
(38; 112; 186) provided on the drive mechanism (35; 186), which
member is formed to engage with the pushrod (14; 188) and which, at
least in the distal end position range of the container (12; 136),
engages elastically with the pushrod (14; 188).
18. The injection device according to one or more of claims 14 to
17, wherein depending upon the position of the container (12) or a
retainer which holds it, the member (27; 38) formed to engage with
the pushrod (14) is prevented from moving elastically away from the
pushrod (14) by a member or the like fixed to the housing.
19. The injection device according to one or more of the preceding
claims, wherein, at least in areas, the pushrod (14; 188) is formed
in the form of a toothed rod (FIGS. 10; 30, 31).
20. The injection device according to claim 19, wherein the teeth
(28; 218, 248) of the toothed rod (14; 188) are formed so that they
permit the toothed rod to move only in the proximal direction
relative to an elastic detent mechanism.
21. The injection device according to one or more of the preceding
claims, wherein the pushrod (14; 188) is associated with a stop
(91) limiting the movement of the pushrod relative to the housing
(15; 132), at least in the proximal direction.
22. The injection device according to one or more of the preceding
claims, wherein the container (12; 136) is associated with a
retainer (17; 54; 134, 234) which holds the container (12; 136) and
can move axially in the housing (15; 132) between a proximal and a
distal end position.
23. The injection device according to claim 22, wherein the length
of the retainer (54; 134, 234) is adjustable.
24. The injection device according to claim 23, wherein the
retainer (54; 134, 234) has a proximal section (56; 134) and a
distal section (66; 234) that are connected to each other by an
adjustable connection (64; 236, 240), in particular by a
micro-detent mechanism which makes it possible to change and in
particular to shorten the overall length of the retainer (54; 134,
234), for example by means of an axial force (FIG. 8A: K).
25. The injection device according to one or more of claims 22 to
24, wherein in its proximal end position, the retainer (54; 134,
234) rests with its distal end against a proximal end section of
the drive member.
26. The injection device according to one or more of the preceding
claims, wherein the effectiveness of the first and/or second
connecting device (27; 38; 112, 114; 122, 124; 242, 244, 246, 248,
214, 216, 218, 220) is a function of the respective position of the
container (12; 136).
27. An injection device having a housing (15; 132, 150), comprising
an injection fluid container (12; 136) disposed in this housing
(15), further comprising a pushrod (14; 188) movable in relation to
the housing (15; 132, 150) to expel fluid from this container (12;
136), further comprising a retainer (54; 134, 234) serving to hold
the container (12; 136) and movable in the housing (15; 132)
between a proximal and a distal end position, and comprising a
device (64; 236, 240) for adjusting the length of this retainer
(54; 134, 234).
28. The injection device according to claim 27, wherein in its
distal range, the retainer (54; 134, 234) has abutment means (68,
73; 236), determining its proximal end position and/or distal end
position relative to the housing (15; 132) and wherein the length
adjustment of the retainer (54; 134, 234) is carried out relative
to these abutment means so that when the length of the retainer
(54; 134, 234) is changed, the position of the container (12; 136)
relative to the pushrod (14; 188) is changed.
29. The injection device according to claim 27 or 28, wherein the
length changing device has a micro-detent mechanism (64; 236, 240)
connecting a proximal section (56; 134) and a distal section (66;
234) of the retainer (54) to each other in an adjustable way.
30. The injection device according to one or more of the preceding
claims, wherein the housing has at least two parts, and a device
(144) is provided for changing the relative position of housing
parts (132, 150), in particular by linearly moving them relative to
each other.
31. The injection device according to claim 30, wherein a first
housing part (132) is provided for guiding the retainer (134, 234)
holding the injection fluid container (136) and a second housing
part (150) that is movable in relation to the first has detent
means (180) for the locking of a detent mechanism (224) provided on
the drive mechanism (186).
32. The injection device according to claim 31, wherein a clip
(176) on the outside of the second housing part (150) is provided
for releasing the detent connection between the detent means (180)
and the detent mechanism (224).
33. The injection device according to one or more of claims 30 to
32, wherein one of the housing parts (150) movable relative to each
other has a thread (148, 148'), and the other housing part (132)
has a threaded sleeve (144) that is rotatable relative to the other
housing part (132) but not axially movable, and is in engagement
with said thread (148, 148').
34. The injection device according to one or more of claims 30 to
33, wherein guide means (152, 156, 196, 198) is provided for linear
guidance between the housing parts (132, 150) that are movable
relative to each other.
35. The injection device according to one or more of claims 30 to
34, wherein one of the housing parts (150) is guided in the other
(132).
36. The injection device according to claim 35, wherein the outer
housing part (132) is provided with at least one elongated recess
(158), through which a part (196) of the inner housing part (150)
protrudes radially outward.
37. The injection device according to claim 36, wherein the
outwardly protruding part (196) of the inner housing part (150) is
provided with an external thread (148, 148') which engages with the
internal thread (146) of a threaded sleeve (144) that is disposed
on the outer housing part (132) so that it can rotate, but cannot
slide axially.
38. The injection device according to claim 33 or 37, wherein the
threads (146, 148, 148') are formed as small pitch threads.
39. The injection device according to one or more of the preceding
claims, wherein the first connecting device (186) comprises two
engaging members (214, 216) that are provided with engaging
elements (214', 216') adapted to engage in corresponding rows of
teeth (218, 220) of a toothed rod (188) that serves as a
pushrod.
40. The injection device according to one or more of the preceding
claims, wherein the second connecting device has two engaging
members (242, 244) that are provided with engaging elements (242',
244') adapted to engage in corresponding rows of teeth (246, 248)
on a toothed rod (188) that serves as a pushrod.
41. The injection device according to claims 39 and 40, wherein the
toothed rod (188) serving as a pushrod has a rectangular, and
preferably square cross section and on a first pair of opposing
sides, is provided with rows of teeth (218, 220) for the first
connecting device and on the second pair of opposing sides, is
provided with rows of teeth (246, 248) for the second connecting
device.
42. The injection device according to claim 41, wherein the
engaging members (214, 216) of the first connecting device and the
engaging members (242, 244) of the second connecting device engage
each other interdigitally.
43. The injection device in particular according to one or more of
claims 39 to 42, wherein the rows of teeth (218, 220) on the
opposing sides of a toothed rod (188) serving as a pushrod and/or
the engaging elements (214', 216') on engaging members which
elastically engage these opposing rows of teeth (218, 220) are
offset from each other in an axial direction in order to permit
either a full engagement of an engaging element of the first of two
elastic engaging members with the associated row of teeth of the
pushrod, or a full engagement of an engaging element of the second
of two elastic engaging members with the associated row of teeth of
the pushrod (188), and thus allow an improved adjustment potential
of the injection device.
44. An injection device having a housing (132, 150) for receiving a
container (136) for a fluid to be injected, and having a toothed
rod that is movable by means of an actuating member to expel fluid
from such a container (136) disposed in the housing, which toothed
rod (188), viewed in cross section, is polygonal and on a plurality
of sides of this polygon, is respectively provided with a row of
teeth (218, 220, 246, 248), said rows of teeth cooperating with
another member, in particular the actuating member, that cooperates
with the toothed rod (188), said another member having a plurality
of engaging members (214, 216), each provided with at least one
engaging element (214', 216') that is complementary to the
associated row of teeth and elastically engages therewith, one
engaging member out of this plurality of engaging members (214,
216) engaging fully with the associated row of teeth (218, 220) via
its at least one complementary engaging element (214', 216'), and
other engaging members out of this plurality of engaging members
being not in full engagement with their associated row of
teeth.
45. The injection device according to claim 44, wherein the rows of
teeth (218, 220) of the toothed rod (188) which cooperate with said
another member are disposed essentially symmetrically to the
longitudinal axis of the toothed rod (188).
46. The injection device according to claim 44 or 45, wherein said
another member is formed as a drive mechanism (186) for moving the
container (136) in the housing (132, 150) of the injection
device.
47. The injection device according to one or more of claims 44 to
46, wherein the toothed rod (188) has a rectangular cross section,
in particular a square one, and said another member has two
engaging members (214, 216) which cooperate with rows of teeth
(218, 220) on opposing sides of this toothed rod.
Description
[0001] The invention relates to an injection device that can
preferably administer a number of injections from the contents of a
container in the injection device. For example, this kind of
injection device is used by patients with pernicious anemia in
order to give themselves regular injections of
hydroxycobalamin.
[0002] In devices of this kind that are used by laymen, it is
important that the operation is simple and easy to understand, and
that the injection does not cause much pain. It is also desirable
that the patient who has a particular fear of needles does not see
the needle directly.
[0003] A great number of semi-automatic 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.
[0004] It is a task or objective of the invention to provide a new
injection device.
[0005] 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 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.
[0006] 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 so 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.
[0007] Suitably, the unidirectional, positive connection is formed
so that an abutment for the distal movement of the container also
constitutes a limitation for the distal movement of the pushrod.
Thus, if the container reaches its distal end position, then a
further movement of the pushrod in the distal direction is
prevented.
[0008] According to another embodiment of the invention, in the
distal end position of the container, the first connecting device
acts in both the proximal and the distal direction, but in the
proximal end position of the container, it is only effective when
the pushrod moves in the distal direction. This produces reliable
operation having a simple structure.
[0009] Another very preferable embodiment of the invention relates
to an injection device which has a drive mechanism for the pushrod
and a second connecting device provided between the drive mechanism
and the pushrod and acting in a path dependent or
direction-dependent manner. The second connecting device is thus
preferably a controlled connecting device, that is, the pushrod
follows the movement of the drive mechanism only when it is logical
and required for the operation of the device. Preferably the second
connecting device is controlled by the position of the container in
relation to the housing, too.
[0010] The second connecting device is also very advantageously
adapted to produce a unidirectional, positive connection between
the drive mechanism and the pushrod when the drive mechanism is
moved in the proximal direction and to move the pushrod along with
the drive mechanism in the proximal direction and to convert a
movement of the drive mechanism in the distal direction into a
corresponding movement of the pushrod in the distal direction as
long as the pushrod is not prevented from moving in the distal
direction. This has turned out to be very advantageous for the
operation of the device, and a relative movement between the drive
mechanism and pushrod permits a simple adjustment of the dosage to
be injected.
[0011] 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.
[0012] A further advantageous embodiment of the second drive
connection is characterized in that in a distal position region of
the container, this second drive connection produces a connection
between the drive mechanism and the pushrod, which is effective in
the proximal direction and permits the drive mechanism to move in
the distal direction relative to the pushrod. After the distal end
position of the container is reached, this makes it possible to
displace the drive mechanism in the distal direction relative to
the pushrod and in this way, to set an injection dosage since the
combined length of the drive mechanism and the pushrod will
increase as a result.
[0013] 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.
[0014] In a very simple embodiment, the pushrod is formed, at least
in some regions, in the form of a toothed rod. Such a toothed rod
is easy and cheap to make, e.g., out of synthetic material. The
teeth of the toothed rod are advantageously formed so that they
only permit a movement of the toothed rod in the proximal direction
in relation to a resilient detent mechanism. The pushrod is also
advantageously associated with an abutment which at least limits
its proximal movement in relation to the housing. By means of this,
the user can see it when the fluid quantity in the container has
been used up, or in this case, the device prevents further
injection procedures in which no more fluid could be injected.
[0015] The container is advantageously associated with a retainer
which receives the container and is displaceable axially in the
housing between a proximal and a distal end position. This protects
the container and makes it possible to insert it into the injection
device towards the end of manufacture, which is desirable for
sterile manufacturing.
[0016] 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 plunger 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.
[0017] 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 shift.
[0018] 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 are the subject-matter of claims 28
and 29.
[0019] An extraordinarily advantageous improvement of the invention
relates to an injection device in which the housing is formed of at
least 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.
[0020] 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 other in order to 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 plunger in a cartridge, which movements are
shorter than 1 mm.
[0021] Further details and advantageous improvements of the
invention are revealed in the exemplary embodiments described below
and shown in the drawings, and are revealed in the other dependent
claims. These exemplary embodiments are in no way to be understood
as limitations of the invention.
[0022] FIGS. 1 to 5 are diagrams which represent the chronological
course of an injection procedure in schematic form,
[0023] FIGS. 6 and 7 are graphic explanations of details from FIGS.
1 to 5,
[0024] 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,
[0025] FIGS. 9A and 9B are representations analogous to FIG. 8, but
in the cocked state,
[0026] 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,
[0027] FIGS. 11A and 11B show a longitudinal section analogous to
FIGS. 8 and 9, but in a plane perpendicular to these two Figs.,
[0028] FIG. 12 shows how a hook of a connecting device engages in
the pushrod of FIG. 10,
[0029] 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,
[0030] 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,
[0031] 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,
[0032] FIG. 16 is a three-dimensional exploded view of internal
parts of the injection device of FIGS. 14 and 15,
[0033] FIG. 17 is a three-dimensional exploded view of the housing
of FIGS. 14 and 15 and a retainer part disposed in it,
[0034] FIG. 18 is a three-dimensional exploded view of a cartridge,
its retainer, and an injection needle,
[0035] 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.degree.,
[0036] FIG. 22 shows a section along line XXII-XXII in FIG. 21,
[0037] 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,
[0038] FIG. 24 is an enlarged detail of area XXIV in FIG. 19,
[0039] FIG. 25 is an enlarged detail of area XXV in FIG. 20,
[0040] 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,
[0041] FIG. 27 shows only the upper and lower rows of teeth of the
pushrod of FIG. 26,
[0042] FIG. 28 shows only the left and right rows of teeth of the
pushrod of FIG. 26,
[0043] FIG. 29 is a schematic representation to explain the
advancing process with an advance by a half a tooth space,
[0044] 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
[0045] 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.
[0046] FIGS. 1 to 5 show the course of an injection process in a
very schematic form.
[0047] FIG. 1 shows the injection device 10 in its rest position
when the spring 11 is not cocked (analogous to the representations
in FIGS. 8A & 8B, FIGS. 11A & 11B, and FIGS. 19 & 20).
FIG. 2 shows the first part of the cocking process of the spring
11, 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).
[0048] FIG. 3 shows the end of the cocking process, in which the
spring 11 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.
[0049] FIG. 4 shows the first phase of an injection, after an
injection process is triggered, in which the needle is inserted,
but no fluid is being injected yet.
[0050] 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.
[0051] 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 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.
[0052] The terms "proximal" and "distal" are standard medical
terminology; they are defined as follows:
[0053] proximal: toward the patient, that is, to the left in FIGS.
1-5.
[0054] distal: away from a patient, that is, to the right in FIGS.
1-5.
[0055] A detent mechanism in the form of a ratchet 27 loaded by a
spring 26 (FIG. 6) is disposed as a first connecting device on a
distal extension 25 of the retainer 17, and this detent mechanism
is formed so that it can engage in a tooth space or notch 28 (FIG.
10) of the pushrod 14, whose preferred three dimensional form is
shown in FIG. 10. This pushrod 14 has an essentially square cross
section with beveled edges 30, which has teeth 28 on two opposing
sides, as shown, and with its radially internal side, the ratchet
27 fits into the teeth 28 of the pushrod 14 that are oriented
toward it.
[0056] 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 in the
proximal direction, the ratchet 27 is slid radially outward and
according to FIG. 5, can slide into the next tooth space 28.
[0057] On the other hand, outside the proximal end position of the
container 12, the inside of the housing 15 prevents the ratchet 27
from moving outward, as FIGS. 2 and 3 clearly show, and thus, in
this position region, a direct drive connection is produced between
the pushrod 14 and the retainer 17, which transmits a proximal
movement of the pushrod 14 directly onto the container 12 and the
needle 22. This drive connection is only interrupted when the
container 12 has reached its proximal end position (FIGS. 1, 4,
& 5), since only at this point can the ratchet 27 be moved
radially outward in the manner described in detail above. This can
also be described as link control or cam control of the ratchet
27.
[0058] It should be emphasized here that there are many potential
variants of the detent mechanism for engaging in the tooth spaces
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.
[0059] 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.
[0060] 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
moved outwardly, counter to the force of a spring. As shown, the
ratchet 38 engages in one of the teeth 28 on the upper side of the
pushrod 14 in FIG. 1, while ratchet 27 on the lower side in FIG. 1
engages in one of the teeth 28 of the pushrod 14. (This is the
reason why teeth or tooth notches 28 are provided on different
sides of the pushrod 14, preferably on two opposite sides.)
[0061] The radially outer end 40 (FIG. 2) of the ratchet 38 is
controlled by the opposing inside 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.
[0062] When the position in FIG. 2 is reached, the retainer 17 with
the 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 space or notch, as shown in FIG. 3, and can engage
there.
[0063] Since the cocking spring 11 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, the detent mechanism 46 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 15 so that it cannot be seen by the user,
which relieves him or her of pre-injection anxiety. The retainer 17
is retained in this position in the housing 15 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 the ratchet 38,
which rests against the pushrod 14 with elastic bias. For its part,
the drive mechanism 35 is locked in the housing 15 by the detent
element 46.
[0064] FIG. 7 shows one possible design of the detent element 46,
which is disposed here so that it can slide 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.
[0065] 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 11 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.
[0066] 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.
[0067] 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 the needle 22 has been
inserted.
[0068] 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.
[0069] As FIGS. 8B 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.
[0070] 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
between certain tolerance limits.
[0071] 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. 8 shows, if there is a gap
between the plunger 23 and the proximal 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.
[0072] This is carried out by virtue of the fact that, through the
use of the micro-detent mechanism 64, the proximal section 56 of
the retainer 54 is moved relative to the distal section 66 until
the pushrod 23 rests without a gap against the proximal end of the
pushrod 14. The micro-detent mechanism 64 maintains this connection
between the sections 56 and 66.
[0073] The distal section 66 has a section 68 with a larger
diameter with which it rests against a collar 70 on the inside of
the housing 15 when in the proximal end position. This section 68
also guides the distal section 66 in a longitudinal groove 84 of
the housing 15 and secures it against rotation.
[0074] 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. 11A and 11B. For clarity,
the total stroke S of the retainer 54 is indicated in FIG. 8A.
[0075] In FIG. 8B, the housing 15 has a sleeve 75 for setting
needle insertion depth and a protective cap 77 can be fitted onto
this sleeve in the manner shown in order to protect the needle 22.
As shown in FIG. 9B, in the cocked position, the needle 22 is
disposed inside the sleeve 75.
[0076] 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 11, 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.
[0077] 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
member 35 and this distance D corresponds to the quantity of fluid
to be injected, i.e. here, the distance between two teeth 28.
[0078] In the embodiment according to FIGS. 8 to 13, the drive
mechanism 35 has a pull knob 80 for compressing the spring 11,
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.)
[0079] 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.
[0080] In the embodiment according to FIGS. 8 to 13, the cocking
spring 11 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 11 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.
[0081] Likewise, the pushrod 14 is guided with an enlargement 88 on
its distal end in two longitudinal grooves 90 on the inside of the
drive member 35 or the knob 80 connected to it. These longitudinal
grooves 90 extend to a position 91. If the enlargement 88 reaches
this point 91, then the pushrod 14 cannot be slid further out of
the drive member 35, and as a result, the actuation step shown in
FIG. 3 is blocked, i.e. the device can no longer be brought into
the cocked position shown in FIG. 3. As a result, the user knows
that no further injection is possible.
[0082] For locking in the cocked position, the drive member 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 member 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 11 is cocked, it engages in the detent recess 48 (FIG. 8A)
in the housing 15.
[0083] 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 to 3.
[0084] The clip 98 is preferably formed as being of one piece with
the part 82 and the spring 11, which greatly simplifies
manufacture. The drive member 35, the knob 80, the pushrod 14, and
the housing 15 are preferably made of the same plastic as the part
82, the spring 11, 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.
[0085] In FIGS. 8, 9, and 11, a particular location in the
injection device is labelled A for greater ease of orientation.
Clearly the representations overlap in the central region.
[0086] FIGS. 11A and 11B 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. 11B, 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 the container 12.
[0087] According to FIG. 11A, 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.degree., for
example, and has a hook 114 on its free, distal end, which engages
in a tooth space 28 of the pushrod 14. The extension 112 and hook
114 are used, in cooperation with the tooth spaces 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 114a of the hook 114 runs at an angle 116 to the pushrod 14,
and the distal, oblique side 114b of the hook 114 runs at an angle
118 to the pushrod 14. Angle 116 is on the order of 90.degree. and
angle 118 is preferably on the order of 15 to 30.degree.. An angle
of 23.degree. turned out to be favorable in tests.
[0088] When the pushrod 14 moves in the distal direction, then it
pulls the hook 114 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 114.
[0089] In an injection procedure, if the pushrod 14 moves in the
proximal direction, then the hook 114, whose side 114b is biased
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 114, and the
retainer 54 is moved in the proximal direction until reaching the
position of FIG. 11B, 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 114 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.
[0090] 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. 11A. 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.
[0091] Here, too, the schematic representation of FIG. 12 applies
with regard to the angles and the preferred values of these angles,
provided that the 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 114,
124 rest elastically, that is, with bias, against the pushrod 14
from opposite sides since then, it is not bent toward one side.
[0092] 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 114
until the abutment 73 abuts against the collar 70. The retainer 54
travels through the path S shown in FIG. 8A.
[0093] 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 114 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.
[0094] When the injection device is triggered by pressing on the
clip 98 (FIG. 9A), the spring 11 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 114, whereby the needle 22 is inserted. After
the insertion, the force-locking, non-positive connection between
the pushrod 14 and the hook 114 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.
[0095] It should be emphasized that the hook 114 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. 11A is also sufficient for a reliable
operation provided that the biasing forces of the extensions 112,
122 and the angles of the teeth 28 are correctly chosen. Tests have
shown that the embodiment according to FIG. 11A 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 112 and 122 in certain
positions and in this way, prevent malfunctions with absolute
certainty.
[0096] FIGS. 14 to 31 show a third embodiment of the invention in
which the user can set the injection dosage in a simple manner and
in which special steps are taken to permit an exact adjustment even
of small injection dosages. Small dosages, for example 1 unit in
the case of insulin, will require very small displacements when
using commercially available cartridges, e.g. in the case of a
known product, a path of the plunger in this cartridge of only 0.27
mm. The invention permits even this kind of small dosage quantity
to be precisely adjusted and injected.
[0097] In this embodiment, the housing of the injection device 130
has a plurality of parts and a tubular housing part 132 as the main
piece, whose shape can best be seen in FIG. 17, where on the right,
this housing part 132 is shown in a partial cutaway view in order
to show its interior.
[0098] 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 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 slid
longitudinally in the housing part 132 for the purpose of adjusting
the dosage.
[0099] 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.
[0100] 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.
[0101] 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 has to change this setting if he
wants to subsequently inject a different dosage.
[0102] If the desired dosage is for example always 3 units, then
the threaded sleeve 144 can remain in this position. This is
particularly advantageous for diabetics with poor eyesight since
changing the setting of the threaded sleeve 144 is not necessary
before an injection. Rather, such a patient only has to cock the
device, place it at the desired spot on the body, and then trigger
the injection, without concerning himself over the dosage.
[0103] If the dosage needs to be changed, then the threaded sleeve
144 must be correspondingly rotated, where a rotation in the
direction of the arrow 164 increases the injection dosage and a
rotation counter to the arrow 164 decreases the injection
dosage.
[0104] As shown in FIG. 15, on its inside, the threaded sleeve 144
has an annular projection (collar) 170 that engages in an annular
groove 172 complementary to it on the outside of the tubular
housing part 132. As shown, the collar 170 and the annular groove
172 have beveled flanks so that the threaded sleeve 144 can simply
be pressed upon the housing part 132 until its collar 170 engages
in the annular groove 172. As a result, after being installed on
the housing part 132, the threaded sleeve 144 can rotate on it, but
cannot slide axially in relation to it.
[0105] The internal thread 146 of the threaded sleeve 144 is so
long that it covers the window 154 (FIG. 17).
[0106] The housing part 150 can slide linearly in the tubular
housing part 132, but cannot rotate relative to it; both parts
together compose the housing of the injection device. The distal
section 174 (FIG. 17) of the housing part 150 essentially has the
shape of a tube with a cylindrical cross section, which has a clip
176 attached to its distal end, whose projection 178 serves to
engage in a radial detent opening 180 of the housing part 150. If
the housing part 150 is displaced linearly in relation to the
housing part 132 (by rotation of the threaded sleeve 144), then the
position of the detent opening 180 moves in relation to the housing
part 132 and this permits an adjustment of the injection dosage:
the more the detent opening 180 is displaced in the distal
direction, the greater the injection dosage will become.
[0107] 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 (FIGS. 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.
[0108] 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.
[0109] 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.)
[0110] 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.
[0111] 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. 25.
[0112] 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.)
[0113] 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.
[0114] 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, whereby the toothed rod 188 then is displaced in the
proximal direction by half a tooth space.
[0115] Furthermore, the advancing part 186 also is provided with an
elastic detent member 224 which engages in the detent opening 180
when the injection device 130 is cocked and which can be pressed
out of the detent opening 180 by pressing on the clip 176 that
serves as a trigger, in order to trigger an injection, as described
in detail in FIGS. 8A and 9A. As shown in FIG. 22, the detent
member 224 is disposed in the free space between two adjacent
engaging members 214, 244, and is disposed opposite an edge of the
toothed rod 188. In this manner, one succeeds in embodying the
injection device in a space-saving way since in this manner, there
is sufficient space available for the spring path of the detent
member 224.
[0116] In order to make the teeth of the toothed rod 188 more
visible, this is shown in FIGS. 16, 30, and 31 with a longitudinal
groove 226. This longitudinal groove 226 does not really exist, as
can be clearly seen from the section in FIG. 22. It is only there
for improved visibility of the teeth.
[0117] 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.
[0118] 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.)
[0119] 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 the teeth 242' fully engage the teeth 246,
as shown in FIG. 24, or only the teeth 244' fully engage the teeth
248.
[0120] Also, the teeth 242', 244', 246, and 248 so are formed that
they permit the toothed rod 188 to slide only in the proximal
direction (arrow 222).
[0121] 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.
[0122] In the same manner, the engaging members 214, 216 of the
advancing part 186 are formed so that they rest against the toothed
rod 188 with bias, as shown with arrows 252 in FIG. 25.
[0123] The biasing forces 250, 252 increase the friction between
the relevant engaging members and the toothed rod 188, which
improves the function and assures a large degree of operational
reliability.
[0124] The fact that the initial biasing forces 250, 252 act
symmetrically on the toothed rod 188, prevents it from being bent
by these forces.
[0125] The schematic representations of FIGS. 26 to 28 will provide
a clearer understanding of the structure of the toothed rod 188.
The axis A-A is shown in all three Figs. to make a simple
orientation possible.
[0126] For greater ease of comprehension, FIG. 26 shows the toothed
rod 188 in a three-dimensional and substantially schematic form. Of
the four rows of teeth, FIG. 26 shows only the two rows of teeth
218 and 248 which have the same tooth spacing and the same phase
position, i.e. their spaces are disposed in the same plane.
[0127] 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.degree..
[0128] 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.degree..
[0129] The rows of teeth 246 and 248 cooperate with the retainer
part 234 (FIG. 17) and are used to drive it analogous to the
driving of part 66 in FIG. 11A.
Assembly
[0130] 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.degree., 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.)
[0131] 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.
[0132] The advancing part 186 is now inserted into this housing
from its distal end. The toothed rod 188 is inserted into the
opening 200 of the advancing part 186 until the engaging members
214, 216 of the advancing part 186 engage in the first teeth on the
proximal end of the toothed rod 188. This corresponds approximately
to the position in FIG. 25, but displaced further to the left by
one tooth.
[0133] Then, a cocking spring 262 (FIG. 16) is inserted from the
distal end into the tubular housing part 132 until it abuts against
the collar 264 of the advancing part 186, the advancing part 186
suitably being engaged lockingly with its elastically deflectable
detent projection 224 in the detent opening 180. Then, a collar
part 266 is fastened with adhesive or in detent fashion in the
distal end of the tubular housing part 132. It serves as an
abutment for the cocking spring 262.
[0134] 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 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.
[0135] After the collar part 266 is fastened, the actuation knob
206 is fastened on the distal end of the advancing part 186, as
described above (Parts 202, 204 in FIG. 16).
[0136] 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. 11A, but cannot be shown in a
longitudinal section. A comparison of FIGS. 19 and 20 shows this
engagement in each other.
[0137] 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.
[0138] 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.)
Operation
[0139] 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.
[0140] The cocking spring 262 (FIG. 16) is then cocked by pulling
the actuating knob 206 in the distal direction, and the detent
projection 224 is made to engage in the detent opening 180.
[0141] 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.
[0142] After the release by means of the trigger 176, the
compressed spring 262 pushes the toothed rod 188 in the proximal
direction via the engaging members 214, 216, and by means of the
engaging members 242, 244 of the retainer part 234, which act like
clamping jaws, this movement is transferred directly to the needle
276 so that it is inserted into the tissue of the patient. The
retainer part 234, with a radial projection 284 (FIG. 20), the
abuts against the annular collar 260 on the inside of the housing
part 132 and thus limits the insertion depth of the needle 276.
[0143] 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
virtue of the fact that the devices according to FIGS. 24 and 25
are essentially identical.
[0144] In this manner, in the present embodiment, a dosage setting
from 1 to 60 units is possible, which covers the requirements of
actual use.
[0145] 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.
* * * * *