Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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76712001.206
LOCKING TENSIONING MECHANISM FOR A MINIATURISED HIGH
PRESSURE ATOMISER
The invention relates to a locking tensioning mechanism for a miniaturised
apparatus for
applying high pressure to a liquid, wherein the volume of liquid delivered is
variable. A
high pressure generator of this kind may be used, for example, in an atomiser
with
which a specified volume of a liquid held under high pressure is atomised to
form an
aerosol. The high pressure generator may also be used to produce a high
pressure jet of
to liquid of preferably very small diameter.
The liquid may, for example, contain a pharmaceutically active substance. The
liquid
may be atomised using a high pressure generator to form an aerosol, e.g. a
pharmaceutical aerosol which is administered through the lungs or the nasal
passages.
Using a needleless injector, a liquid medicament can be administered or
injected
parenterally or the device is used to produce an aerosol mist for application
to the eye.
The aim of the invention is to expand the range of uses of a miniaturised high
pressure
generator of this kind and to adapt the devices to the user's requirements.
In the known locking tensioning mechanisms (W.Krause: Konstruktionselemente
der
Feinmechanik, Verlag Carl Hanser, Miinchen 1993, pages 521 to 523) the energy
stored
in a spring is released when required and converted into motion. The spring
acts on a
guided or mounted component, referred to as the spring component. A locking
member
prevents the spring component from moving and releases it in a predetermined
manner.
WO 97/20590 discloses a locking tensioning mechanism for a spring-operated
power
take-off. This locking tensioning mechanism essentially comprises a power-
transmission
gear, e.g. a helical thrust gear, for tensioning the spring which applies the
power
3o required for the specified high pressure, an annularly arranged locking
member with
engaging locking surfaces and an actuating button, a spring component and two
stops as
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travel limners for the spring component. These components are accommodated in
a two-
part housing; the two parts of the housing are mounted so as to be rotatable
relative to
one another. In order to tension the spring the two housing parts are rotated
relative to
one another (e.g. by hand), the helical thrust gear thereby converting the
rotary
movement of the two housing parts relative to one another into a compression
of the
spring. At the end of the rotary movement of the two housing parts relative to
one
another the locking member jumps into its position of engagement and holds the
spring
component and hence the tensioned spring in this position. If the miniaturised
high
pressure generator is e.g. an atomiser according to WO 97112687, the outlet
nozzle
1o producing the aerosol mist is held in front of or inside a body cavity, and
the atomising
process is initiated by operating the actuating button. If the high pressure
generator is a
generator of a spray jet, e.g. a needleless injector according to WO 01/64268,
the nozzle
is pressed against the animal or plant tissue, the needleless injector is
actuated by
operating the actuating button, and a volume of a liquid is injected into the
tissue.
The high pressure generators with the locking tensioning mechanism described
in WO
97/20590 reproducibly deliver a given volume of a liquid in the microlitre
range. The
volume delivered is determined by the construction and cannot subsequently be
altered.
The volume can only be changed by modifying the construction, which is a
2o comparatively expensive process, as the tools for producing the individual
components
have to be adapted to the altered specification.
The problem of the present invention is to provide a high pressure generator
having a
locking tensioning mechanism with means for adjusting the volume to be
delivered,
without altering the essential components of the locking tensioning mechanism
or the
high pressure generator. The locking tensioning mechanism for the spring-
operated
power take-off comprises essentially the following components: two housing
parts
mounted to be movable relative to one another, an operating spring which acts
as a store
for the mechanical energy acting on a power takeoff flange as the spring
component, a
3o device for tensioning the operating spring, a first and a second stop for
the spring
component which respectively determine the first and second resting positions
of the
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spring component, a piston connected to the spring component which is moved
axially
in a cylinder as the spring component moves, the piston expelling the volume
of liquid
as it moves towards an outlet nozzle .
This problem is solved according to the invention by at least one additional
component
which varies the position of one of the two stops for the spring component and
thereby
alters the distance travelled by the spring component.
The two housing parts which are movable relative to one another may be mounted
so as
l0 to be rotatable relative to one another about their axis or axially movable
relative to one
another. The operating spring may be tensioned by means of a helical thrust
gear in the
case of housing parts which are mounted so as to be rotatable relative to one
another, for
example. When the housing parts are mounted to be slidable relative to one
another one
housing part may be pulled out from the other housing part to a limited extent
in order to
15 tension the operating spring. The piston connected to the spring component
may be a
solid piston or a hollow piston. The spring component may, for example, be
disc-shaped
or cup-shaped.
The first stop for the spring component forms the travel limner for the spring
component
2o in its first resting position in which the operating spring is tensioned.
In this state the
locking member is engaged. The second stop for the spring component forms the
travel
limner for the spring component in its second resting position, in which the
operating
spring is relatively relaxed. In this state the locking member is disengaged.
By rotating
the two housing parts relative to one another the spring component is pushed
from its
25 second resting position into its first resting position by means of the
helical thrust gear
in order to tension the operating spring. After the locking member has been
disengaged
by operating the actuating button the operating spring pushes the spring
component
from its first resting position into its second resting position.
3o The minimum of one additional component by means of which the position of
the
second stop for the spring component is changed may be, for example:
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~ a spacer disc or a spacer ring of constant thickness,
~ a pair of stepped discs of variable thickness,
~ a plurality of pins or screws arranged outside the axis of the device, in
the bottom of
the cup-shaped spring component or in the housing part which contains the
locking
member,
~ a locknut screwed onto the spring component,
~ an adjustable abutment plate,
~ a screw mounted centrally with respect to the axis of the device,
~ a second stop which can be varied over a number of stages, with which the
volume to
l0 be delivered by the high pressure generator can be divided into a number of
portions,
~ a helical thrust gear for setting a stop of the spring component, the
helical thrust gear
comprising a rotatable adjusting ring and an axially movable ring, both of
which have a
helicoidal surface.
The helical thrust gear for setting a stop of the spring component is to be
distinguished
from the helical thrust gear for tensioning the operating spring mentioned
above by way
of example.
For example, the second resting position of the spring component can be varied
as
2o follows:
A disc or ring of constant thickness is placed on the bottom of the cup-shaped
spring
component, preferably in the form of a cylinder open at one end. The travel of
the spring
component is altered by an amount equal to the thickness of the disc or ring.
The disc or
ring may be clamped or glued in the spring component. The edge of the disc or
ring may
be smooth or provided with gripping serrations.
The spring component is provided, inside its base, with a plurality of blind
holes (e.g.
with three holes which are azimuthally offset from each other by 120 degrees).
Pins are
inserted into the blind holes, from which they protrude. The travel of the
spring
3o component is altered by an amount equal to the part of the pins protruding
from the
blind holes.
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Screws are inserted in the blind holes. The travel of the spring component is
altered by
an amount equal to the part of the screws protruding from the blind holes. The
base of
the spring component is provided with several (e.g. three) through-holes into
which
screws projecting into the interior of the spring component are inserted from
the side of
the spring component facing the spring. The travel of the spring component is
altered by
an amount equal to the length of the sections of the screws projecting into
the interior of
the spring.
Screws acting on the second stop for the spring component are screwed into the
upper
to housing part from the nozzle end of the high pressure generator. These
screws may be
accessible from the outside.
A central screw with a hollow piston secured therein is screwed into the base
of the
spring component. The part of the central screw projecting into the interior
of the cup-
shaped spring component alters the travel of the spring component. In this
embodiment
of the invention the hollow piston is forcibly pushed further into the
cylinder by this
same amount. The clearance volume in front of the end of the hollow piston
facing the
outlet nozzle remains virtually unchanged.
2o The position of one of the two stops of the spring component of the locking
tensioning
mechanism may also be altered by means of a rotatable adjusting ring which
cooperates
with an axially movable ring in the manner of a helical thrust gear. The
rotatable
adjusting ring has a handle projecting from the housing and accessible from
outside. The
rotatable adjusting ring and the axially movable ring each have a helicoidal
surface in
which the two rings slide relative to one another. The helicoidal surface may
be a right-
handed screw or a left-handed screw.
The rotatable adjusting ring is rotatably mounted inside the housing. It may
be axially
supported against the housing on its side opposite the helicoidal surface
axial. The
3o axially movable ring is secured against rotation inside the housing. The
side of the
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movable ring located opposite the helicoidal surface is one of the two stops
of the spring
component of the locking tensioning mechanisms, either the first or the second
stop.
The rotatable adjusting ring may be positioned as desired within a given
angular range
in both directions of rotation. The prescribed range of rotation is limited by
the actual
construction, e.g. to less than 180 degrees, preferably less than 90 degrees.
When the rotatable adjusting ring is rotated, this alters the spacing of the
abutment
surface of the axially movable ring from the side on which the rotatable
adjusting ring is
supported against the housing. This reproducibly changes the position of the
first or
to second stop of the spring component of the locking tensioning mechanism and
adjusts
the permitted travel of the spring component.
The helicoidal surface of the helical thrust gear may be a single-threaded
helicoidal
surface if the angle of rotation of the rotatable adjusting ring is less than
90 degrees, for
example. For reasons of strength and uniform distribution of force within the
helical
15 thrust gear it may be advisable to construct the helicoidal surface as a
multi-threaded
helicoidal surface, for example as a double-, triple- or quadruple-threaded
helicoidal
surface.
The helicoidal surfaces on the rotatable adjusting ring and on the axially
movable ring
may be continuous, over an angle of up to 360 degrees in the case of a single-
threaded
2o helicoidal surface, up to an angle of 180 degrees in each case, in the case
of a double
threaded helicoidal surface, and up to an angle of 90 degrees in each case, in
the case of
a quadruple-threaded helicoidal surface. In addition, the helicoidal surfaces
on one or
both rings may be present only partially over a smaller one of these angles.
The thread height of the helicoidal surfaces is equally great in a pair of
cooperating
25 rings. The thread height may be selected freely within a range determined
by the
manufacturing constraints. Within limits imposed by the construction, the
distance
travelled by the axially movable ring at a given angle of rotation of the
rotatable ring
can be adjusted by a suitable thread height of the helicoidal surface.
The helical thrust gear may have engaging means - preferably in the form of
engaging
3o teeth, for example - which prevent the helical thrust gear from being
shifted
accidentally. Such a gear can only be shifted if there is a sufficient
rotational force
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acting on the rotatable adjusting ring. The engaging means may be provided on
the side
of the rotatable adjusting ring on which the adjusting ring rests on the
housing.
Moreover, the engaging means may be provided on the helicoidal surfaces -
preferably
for example in the form of engaging teeth or engaging steps.
If the helicoidal surfaces are provided in each case on one edge of each ring,
the
rotatable adjusting ring can only push the axially movable ring in front of
it; the
rotatable adjusting ring cannot pull the axially movable ring back. In this
embodiment of
the helical thrust gear the axially movable ring can be pressed against the
adjusting ring
by means of a resetting spring.
1o
In another embodiment the helicoidal surfaces may be provided in or on the
cylindrical
wall of the rings, for example as double-threaded detents in one ring and as
double-
threaded cams in the other ring. The cams slide in the detents, and the
axially movable
ring can be pushed in both axial directions as the rotatable adjusting ring is
rotated. In
15 this embodiment no resetting spring is required. The cams may for example
be shaped
as helicoidal surfaces; they may also be shaped as cylinders protruding from
the wall.
In another embodiment it is possible to mount one of the helicoidal surfaces
not on the
axially movable ring but directly on the side of the spring component facing
the
2o rotatable adjusting ring, if the axially movable spring component is
secured against
rotation inside the housing. In this embodiment either the first stop or the
second stop of
the spring component may be constructed as a helicoidal surface, and
consequently the
position of the first stop or second stop can be varied.
25 The locking tensioning mechanism according to the invention has the
following
advantages:
~ Depending on the particular embodiment of the invention the volume to be
delivered
by the high pressure generator can easily be altered during the assembly of
the high
pressure generator, or before it is used or while it is being used.
~ The volume of liquid to be delivered may be varied either continuously or
stepwise.
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~ The operating range of the operating spring during the expulsion of the
volume of
liquid begins with the change, according to the invention, in the second
resting position
of the spring component under high spring tension. The particle size
distribution of the
aerosol produced by the high pressure generator or the speed which the
needleless
injector imparts to the volume of liquid expelled remain virtually unchanged
by the
change in the second stop for the spring component.
~ When the position of the second stop for the spring component is changed
according to
the invention, the position of the first stop for the spring component as well
as the nature
and mode of operation of the locking member are unaffected.
to ~ If, in a locking tensioning mechanism for a high pressure atomiser or for
a needleless
injector, not only is the second stop for the spring component altered, but
the position of
the (hollow) piston in relation to the spring component is also altered to the
same extent,
the clearance volume for the liquid located inside the cylinder between the
end of the
(hollow) piston facing the outlet nozzle and the nozzle body can be kept at a
prescribed
value.
The invention is preferably used in a high pressure generator according to
Patent
Application WO 91/14468 or WO 97/12687, i.e. atomisers for producing
pharmaceutical aerosols for administration by inhalation or by nasal route, a
needleless
2o injector according to WO 01/64268 or an eye spray device according to
PCT/EP0207038.
The devices mentioned above are based on the same mechanism for applying high
pressures to a given amount of a liquid. For example, this discussion will
therefore be
directed to the high pressure generator mentioned above. In the event of any
differences
or inconsistencies in the specific descriptions between the embodiments of the
invention
mentioned above or illustrated in the Figures, and the embodiments that
follow, the
embodiments described above and those illustrated in the Figures are preferred
over the
embodiments that follow.
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An apparatus of this kind for propellant-free atomisation of a metered
quantity of a liquid
pharmaceutical composition is described in detail for example in International
Patent
Application WO 91/14468 "Atomizing Device and methods" and also in WO
97/12687, in
Figures 6a and 6b and the associated description. In a nebuliser of this kind
a
pharmaceutical solution is converted into an aerosol with an average particle
size (mean
aerodynamic diameter) of less than 20 microns by the application of high
pressures up to
500 bar and sprayed. Reference is hereby made to the abovementioned
publications in their
entirety within the scope of the present specification.
to In nebulisers of this kind the formulation solutions are stored in a
reservoir. The active
substance formulations used must have sufficient stability when stored and at
the same
time must be such that they can be administered directly, if possible without
any further
handling, to suit the medicinal purpose. Moreover they should not contain any
ingredients
that are able to interact with the nebuliser in such a way that the nebuliser
or the
pharmaceutical quality of the solution, or of the aerosol produced, might be
harmed.
To nebulise the solution a special nozzle is used as described for example in
WO 94/07607
or WO 99/16530, particularly Figure 1 and the associated description.
Reference is hereby
specifically made to both publications.
The preferred atomiser essentially consists of an upper housing part, a pump
housing, a
nozzle, an adapter, the locking mechanism according to the invention, a spring
housing, a
spring and a storage container, the outstanding features of the nebuliser
being as follows:
- a pump housing which is secured in the upper housing part and which
comprises at
one end a nozzle body with the nozzle or nozzle arrangement,
- a hollow piston with valve body,
- a power takeoff flange in which the hollow piston is secured and which is
located
in the upper housing part,
- the locking mechanism according to the invention situated in the upper
housing
3o part,
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- a spring housing with the spring contained therein, which is rotatably
mounted on
the upper housing part by means of a rotary bearing,
- a lower housing part which is fitted onto the spring housing in the axial
direction,
and
- an adapter in the form of a hollow cavity with two opposite openings, the
smaller
opening fitting closely around at least the point of exit of the aerosol from
the
nozzle, and the larger opening having a contour which makes it possible to fit
this
opening over an eye.
The hollow piston with valve body corresponds to a device disclosed in WO
97/126$7. It
to projects partially into the cylinder of the pump housing and is axially
movable within the
cylinder. Reference is made in particular to Figures 1 to 4, especially Figure
3, and the
relevant parts of the description. The hollow piston with valve body exerts a
pressure of 5
to 60 Mpa (about 50 to 600 bar), preferably 10 to 60 Mpa (about 100 to 600
bar) on the
fluid, the measured amount of active substance solution, at its high pressure
end at the
moment when the spring is actuated. Volumes of 10 to SO microlitres are
preferred, while
volumes of 5 to 20 microlitres are particularly preferred and a volume of 15
microlitres per
spray is most particularly preferred.
The valve body is preferably mounted at the end of the hollow piston facing
the valve
body.
2o The nozzle in the nozzle body is preferably microstructured, i.e. produced
by
microtechnology. Microstructured nozzle bodies are disclosed for example in
WO-94/07607; reference is hereby made to the contents of this specification,
particularly
Figure 1 therein and the associated description.
The valve body consists for example of two sheets of glass and/or silicon
firmly joined
together, at least one of which has one or more microstructured channels which
connect the
nozzle inlet end to the nozzle outlet end. At the nozzle outlet end there is
at least one
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round or non-round opening 2 to 10 microns deep and 5 to 15 microns wide, the
depth
preferably being 4.5 to 6.5 microns while the length is preferably 7 to 9
microns.
In the case of a plurality of nozzle openings, preferably two, the directions
of spraying of
the nozzles in the nozzle body may extend parallel to one another or may be
inclined
relative to one another in the direction of the nozzle opening. In a nozzle
body with at
least two nozzle openings at the outlet end the directions of spraying may be
at an angle of
20 to 160° to one another, preferably 60 to 150°, most
preferably 80 to 100°. The nozzle
openings are preferably arranged at a spacing of 10 to 200 microns, more
preferably at a
spacing of 10 to 100 microns, most preferably 20 to 50 microns. Spacings of 22
to 28
to microns are most preferred. The jets will therefore meet right in front of
the nozzle
openings.
As already mentioned, the liquid pharmaceutical preparation is under an entry
pressure of
up to 600 bar, preferably 200 to 300 bar, at the entrance to the nozzle body
and is atomised
into an inhalable aerosol through the nozzle openings. The preferred particle
sizes of the
aerosol are up to 20 microns, preferably 3 to 10 microns.
The lower housing part is pushed axially over the spring housing and covers
the mounting,
the drive of the spindle and the storage container for the fluid.
When the atomiser is actuated the upper housing part is rotated relative to
the lower
housing part, the lower housing part taking the spring housing with it. The
spring is
thereby compressed and biased by means of the helical thrust gear and the
locking
mechanism engages automatically. The angle of rotation is preferably a whole-
number
fraction of 360 degrees, e.g. 180 degrees. At the same time as the spring is
biased, the
power takeoff part in the upper housing part is moved along by a given
distance, the
hollow piston is withdrawn inside the cylinder in the pump housing, as a
result of which
some of the fluid is sucked out of the storage container and into the high
pressure chamber
in front of the nozzle.
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If desired, a number of exchangeable storage containers which contain the
fluid to be
atomised may be pushed into the atomiser one after another and used in
succession. The
storage container contains the aqueous aerosol preparation according to the
invention.
The atomising process is initiated by pressing gently on the actuating button.
As a result,
the locking mechanism opens up the path for the power takeoff member. The
biased
spring pushes the piston into the cylinder of the pump housing. The fluid
leaves the nozzle
of the atomiser in atomised form.
If desired, some of the elements of the nebuliser that come into contact with
the liquid
being administered as it travels from the storage container to the nozzle may
be made of
oligodynamically active ingredients or be coated with germicidal materials.
Alternatively,
or in addition, a germ-repellent filter may be formed in this pathway. Such
embodiments
have the advantage that no pathogens can get into the storage container from
outside and
therefore there is no need to add any preservatives. This is particularly
advantageous for
long-term use, as explained hereinbefore.
Further details of construction are disclosed in PCT Applications WO 97/12687
and
WO 97/20590, to which reference is hereby made once more.
The components of the atomiser (nebuliser) are made of a material which is
suitable for its
purpose. The housing of the atomiser and, if its operation permits, other
parts as well are
preferably made of plastics, e.g. by injection moulding. For medicinal
purposes,
2o physiologically safe materials are used.
Fi ores
The invention is explained more fully by means of the drawings. Figure 1 a and
Figure
1b show a longitudinal section through a locking tensioning mechanism
according to the
prior art, i.e. without an additional component according to the invention.
The upper
cylindrical housing part (1) engages over the spring housing (2), to which it
is connected
by means of snap-in lugs (3). The snap-in lugs (3) are provided on the outside
of the
spring housing (2) and may extend over two opposing segments of a circle, each
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measuring 30 degrees. They engage in an encircling groove on the inside of the
upper
housing part ( 1 ). The two housing parts are also rotatable relative to one
another. In the
spring housing is the compression spring (4), which is generally already
pretensioned
when the two housing parts are put together. The compression spring (4) is
supported on
an encircling projection on the lower end of the spring housing as well as on
the spring
component (5), which is mounted so as to be paraxially movable between the
upper
housing part and the spring housing, and which in turn bears on the upper
housing part
( 1 ). The cup-shaped spring component (5) proj ects into the upper housing
part ( 1 ). The
annular locking member (6) surrounds the spring component. The actuating
button (7)
l0 provided on the locking member projects laterally from the upper housing
part.
The collar of the cup-shaped spring component is provided e.g. on its inside
with two
saw-tooth-shaped recesses over which two saw teeth in the upper housing part
slide. The
saw teeth and the recesses are shown in highly simplified form in Figure 1 a.
When the
upper housing part is rotated counter to the spring housing the axially
movable spring
component is pressed further into the spring housing counter to the force of
the
compression spring. As soon as the upper edge of the cup-shaped spring
component has
been pressed sufficiently far down by the locking member, the annular locking
member
moves perpendicular to the housing axis (dotted line in the drawings) between
the upper
edge of the cup-shaped spring component and an annular projection in the upper
2o housing part and secures the spring component and the compression spring
which has
been (additionally) biased by the movement of the spring component in the
position
reached.
By pressing the actuating button (7) the annular locking member (6) is pushed
back
perpendicular to the housing axis, thereby freeing the spring component to
move. The
compression spring pushes the spring component upwards over a given distance
by
means of the annular locking member and thereby actuates a component connected
to
the spring component, but not shown in Figure 1 a and Figure 1 b, e.g. it
moves a piston
in a cylinder.
3o In Figure 1 a the locking tensioning mechanism with the spring component is
shown in
its second resting position and with the locking member disengaged. Figure 1 b
shows
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the locking tensioning mechanism with the spring component in its first
resting position
and the locking member engaged. The first stop (8) is the travel limner for
the spring
component in its first resting position, the second stop (9) is the travel
limner for the
spring component in its second resting position. By rotating the two housing
parts
relative to one another the state shown in Figure 1 a changes into the state
shown in
Figure 1b. After the actuating button has been pressed the force of the
tensioned
compression spring changes the state according to Figure 1 b into the state
according to
Figure 1 a. In Figures 1 a and 1 b the distance (a) is the distance travelled
by the spring
component.
to
Figures 2 to 7 show various locking tensioning mechanisms according to the
invention,
in which the travel of the spring component is variable.
Figure 2 shows the spring component (5) in its second resting position, while
the spring
component bears on the second stop (9). In addition to the components
described, the
flat ring (10) is disposed on the bottom of the cup-shaped spring component
(5). This
ring is placed in the spring component during the assembly of the locking
tensioning
mechanism. The travel (b) of the spring component is altered by an amount
equal to the
thickness of the flat ring (10). The ring (10) alters the quantity of liquid
which can be
2o expelled by a piston (not shown) connected to the spring component (5).
Figure 3 also shows the spring component (5) in its second resting position,
while the
spring component bears on the second stop (9). On the bottom of the cup-shaped
spring
component is a two-part stepped disc ( 11 a; 11 b), which is placed in the
spring
component during the assembly of the locking tensioning mechanism. Each of the
two
discs ( 11 a) and ( 11 b) comprises a plurality of steps, e. g. four steps, on
the sides facing
one another, each step being provided several times, e.g. three times, on each
disc. The
four steps of equal height are each offset from one another by an angle of 120
degrees.
If the highest step on one disc is located on the lowest step of the other
disc, the two-part
3o stepped disc is at its minimum thickness. If the highest step on one disc
is located on the
highest step of the other disc, the two-part stepped disc is at its maximum
thickness. The
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travel (c) of the spring component is altered by an amount corresponding to
the
thickness of the two-part stepped disc (1 la; l 1b).
Figures 4a and 4b show the spring component (5) in its second resting
position, while
the spring component bears on the second stop (9). A plurality of adjustment
screws are
screwed into the upper housing part (1), which are offset from one another by
120
degrees, for example, in the case of three screws. Figures 4a and 4b show only
one of
these screws in each case. The adjustment screws (12) are also accessible from
outside
after the assembly of the locking tensioning mechanism. All the adjustment
screws (12)
to on a locking tensioning mechanism are screwed in to the same depth, but the
specified
depth of penetration may be different within the adjustment area and may be
varied
continuously. The ends of the adjustment screws within the upper housing part
(1)
determine the second stop (9) for the spring component. In Figure 4a the
adjustment
screws (12) are screwed in less deeply than in Figure 4b. The travel (dl) of
the spring
component in Figure 4a is longer than the travel (d2) of the spring component
in Figure
4b.
Figures Sa and Sb show the spring component (5) in its second resting
position. The
spring component is provided, at its end facing the spring (4), with a locknut
(13) which
2o can be turned by different amounts onto the spring component. In the second
resting
position of the spring component the top of the locknut (13) bears on the stop
(9). The
further the locknut (13) is screwed onto the spring component, the shorter the
travel of
the spring component. The travel (e2) is shorter than the travel (e1).
Figures 6a and 6b show, apart from the locking tensioning mechanism, a
cylinder (21)
which is fixed in the upper housing part (1), and a hollow piston (22) which
is fixed in
the spring component (5). At the end of the cylinder is the nozzle (23). The
travel of the
hollow piston is also exactly the same length as the travel of the spring
component. On
the base of the cup-shaped spring component is a plate (24), the spacing of
which from
3o the bottom of the cup-shaped spring component is continuously variable by
means of
adjustment screws (25). The adjustment screws (25) are accessible from outside
after the
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assembly of the locking tensioning mechanism. The further the plate (24) is
from the
bottom of the cup-shaped spring component, the shorter the travel of the
spring
component. The travel (f2) is shorter than the travel (fl). Figures 6a and 6b
are similar
in their content to Figures 6a and 6b of WO 97/12687, which show a nebuliser
which is
preferably used as an inhaler. Reference is specifically made to these Figures
and the
associated remarks within the scope of the present invention. Reference is
also made to
Figures 1 and 2 of WO 01/64268, which show a needleless injector and to
Figures 4 and
of PCT/EP0207038, which illustrate an apparatus for producing an eye spray.
l0 Figures 7a and 7b show a locking tensioning mechanism, a cylinder (21)
secured in the
upper housing part (1) and a hollow piston (26). The hollow piston is fixed in
the central
adjusting screw (27) which can be screwed to different depths into the bottom
of the
cup-shaped spring component. The central adjusting screw (27) is accessible
from the
outside after the assembly of the locking tensioning mechanism. The more
deeply the
central adjusting screw is screwed into the bottom of the cup-shaped spring
component,
the shorter the travel of the spring component and hence the travel of the
hollow piston
within the cylinder. In this arrangement of the hollow piston the clearance
volume (28)
between the nozzle and the nozzle end of the hollow piston remains unchanged
when
the central adjusting screw is screwed to different depths into the bottom of
the spring
2o component. The travel (g2) is shorter than the travel (g1).
Figures 8 to 14 show details of a helical thrust gear for setting a stop of
the spring
component.
Figure 8 shows the rotatable adjusting ring (32) and the axially movable ring
(36) in
exploded view. The rotatable adjusting ring (32) shown in Figure 8a is located
within
the housing (31) (shown only in part). The handle (33) of the rotatable
adjusting ring is
accessible from the outside and can be moved within a slot in the housing. On
one edge
of the rotatable adjusting ring there are engaging teeth (35) which cooperate
with
engaging teeth (not shown) in the housing. The other edge of the rotatable
adjusting ring
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is a double-threaded helicoidal surface (34a; 34b). Each of the two screw
threads
extends over an angle of 180 degrees.
The slidable ring (36) shown in Figure 8b also has a double-threaded
helicoidal surface
(37a; 37b) on the edge facing the rotatable adjusting ring (32). Each of the
two screw
threads extends over an angle of 180 degrees. The double-threaded helicoidal
surface of
the axially movable rings has the same thread height as the double-threaded
helicoidal
surface of the rotatable adjusting ring.
The axially movable ring is prevented from rotating by means of guide bars
(38). The
guide bars slide in grooves (not shown) in the housing.
1o The helicoidal surface of the axially movable ring (36) is pressed against
the helicoidal
surface of the rotatable adjusting ring by the resetting spring (39). The
helical spring is
shown in cross section. As the rotatable adjusting ring is rotated, the
helicoidal surface
(34a) slides over the helicoidal surface (37a) and the helicoidal surface
(34b) slides over
the helicoidal surface (37b).
The smooth edge (40) of the axially movable ring (36) is the abutment for the
spring
component (not shown) of the locking tensioning mechanism.
Figure 9 shows another embodiment of a helical thrust gear for setting a stop
of the
spring component. Figure 9a corresponds to Figure 8a. Of the helicoidal
surface (37a;
37b) in Figure 8b, only the end surfaces (41 a; 41 b) and (42a; 42b) on the
four
projections are retained in Figure 9b. The remaining areas of the helicoidal
surface
(37a; 37b) are cut away. The helical spring (40) (shown in cross section)
presses the end
surfaces (41a; 41b) against the helicoidal surface (34a) and the end surfaces
(42a; 42b)
against the helicoidal surface (34b) of the rotatable adjusting ring.
The azimuthal spacings between the projections, for example four projections,
may be
90 degrees in each case. The azimuthal spacings may optionally be of different
sizes.
The free spaces between the projections may be used for other purposes, for
example
for construction elements provided between the housing wall and the inner
region of the
two rings.
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Figure 10 shows another embodiment of a helical thrust gear for setting a stop
of the
spring component. In this Example the rotatable adjusting ring (52) has two
cams on its
outer wall (54a; 54b). The axially movable ring (56) has two detents (55a;
SSb), which
are parts of a double-threaded helicoidal surface. The external diameter of
the rotatable
adjusting ring (52) is almost as great as the internal diameter of the axially
movable ring
(56). When the two rings are fitted into one another the two cams (54a; 54b)
engage in
the detents (55a; SSb). When the rotatable adjusting ring (52) is rotated
counter to the
axially movable ring (56) the cams slide in the detents. The cams move the
ring (56)
axially in each direction of rotation of the rotatable adjusting ring. There
is no need for a
1 o resetting spring for the axially movable ring in this embodiment.
The cams or the detents, respectively, may be associated with the two rings in
a different
manner. For example, the cams may be provided on the inner wall of the axially
movable ring and the detents in the wall of the rotatable adjusting ring. It
may be
expedient to make the radial depth of the detents smaller than the radial
thickness of the
ring provided with detents.
The cams shown in Figure 10a have a shape resembling a helicoidal surface.
Their
height in the axial direction substantially corresponds to the height of the
detents in the
axial direction. Instead of cams of this kind, cylindrical cams may be used,
for example,
the diameter of which is substantially as great as the height of the detents
in the axial
2o direction.
Figure 11 shows another embodiment of a rotatable adjusting ring (62) and an
axially
movable ring (66) in diagonal view. Both rings have a quadruple-threaded
helicoidal
surface, each provided with two engaging steps. The helicoidal surfaces (64a;
64d) on
the rotatable adjusting ring are visible in Figure l la; the other two
helicoidal surfaces on
the rotatable adjusting ring are hidden in Figure l la. The axially movable
ring (66) has
the four corresponding helicoidal surfaces (67a; 67b; 67c; 67d), which
cooperate with
the associated helicoidal surfaces on the rotatable adjusting ring.
Each of the four helicoidal surfaces on each of the two rings merges into two
engaging
3o steps, of which the four "high" steps in each case are in one plane and the
four "low"
steps are in a plane parallel thereto. The two planes are perpendicular to the
axis of the
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rotatable adjusting ring. The "high" steps on the rotatable adjusting ring
extend in each
case over an angle which is essentially exactly the same size as the angle
over which the
"low" steps on the axially movable ring extend. The "low" steps on the
rotatable
adjusting ring extend in each case over an angle over which the "high" steps
on the
axially movable ring extend.
The "high" steps on the rotatable adjusting ring may in each case be provided
with a
recess, of which only the recess (65a) is visible in one of these four steps
in Figure 1 la;
the recesses in the other "high" steps of the rotatable adjusting ring are
hidden in Figure
11 a. The recesses in the "high" steps of the rotatable adjusting ring extend
in each case
to over an angle which is substantially equal to the angle over which the
"high" steps of
the axially movable ring extend.
Figure 12 shows the two rings of the helical thrust gear for setting a stop of
the spring
component of the locking tensioning mechanism in the position in which the
"high"
steps of one ring are located in the "low" steps of the other ring. Figure 12a
shows this
arrangement in diagonal view and Figure 12b shows a longitudinal section
through the
axis of the rings. Figure 12b shows the recess (65c), which is now visible.
In Figure 13 the two rings of the helical thrust gear for setting a stop of
the spring
2o component of the locking tensioning mechanism are shown in the position in
which the
"high" steps of both rings are located one above the other. Figure 13a shows
the
arrangement viewed diagonally and Figure 13b shows a longitudinal section
through the
axis of the two rings. Figure 13a shows the two recesses (65a; 65d), while
Figure 13b
shows the recesses (65b; 65c) which are now visible.
Figure 14 shows the arrangement of the helical thrust gear for setting a stop
of the
spring component within the housing in longitudinal section through the axis
of the
housing, which coincides with the axis of the two rings. Figure 14a shows the
position
of the two rings corresponding to Figure 12 and Figure 14b shows those
corresponding
3o to Figure 13. In Figures 14a and 14b the thread height of the helicoidal
surfaces is
shown exaggeratedly large.
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The housing (31 ) contains the operating spring (4), one end of which abuts on
the spring
component (5). The spring component bears on the stop (40) on one side of the
axially
movable ring (66). The quadruple-threaded helicoidal surface of the axially
movable
ring cooperates with the helicoidal surface of the rotatable ring (62). The
axially
movable ring (66) is prevented from rotating by means of the guide bars (38),
which
slide in guide grooves in the wall of the housing. The resetting spring (39)
holds the
axially movable ring in contact with the rotatable adjusting ring.
Figure 14c shows a cross section through the arrangement according to Figure
14a level
to with the plane A - A.
In the embodiment of the invention according to Figures 11 to 14 the rotatable
adjusting
ring can be rotated through 90 degrees between the two positions of
engagement. The
axially movable ring (66) then moves, taking with it one stop of the spring
component
15 (5), by a distance (X), which is shown between the two Figures.
Within the scope of the invention there are other possible ways of varying the
travel of
the spring component. It may be expedient to divide the travel of the spring
component
into a number of parts which are covered one after another. This makes it
possible, for
2o example, with a needleless injector, to deliver the quantity of liquid
corresponding to the
travel of the spring component laid down by the helical thrust gear for the
purpose of
tensioning the operating spring on the transition from the second resting
position into
the first resting position, in a plurality of partial amounts, without re-
activating the
locking tensioning mechanism of the needleless injector all the time.
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