(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2002/0052578A1
`Moller
`(43) Pub. Date:
`May 2, 2002
`
`US 20020052578A1
`
`(54) INJECTION DEVICE
`(76) Inventor: Claus Schmidt Moller, Fredensborg
`(DK)
`Correspondence Address:
`PATENT DEPARTMENT
`SKADDEN, ARPS, SLATE, MEAGHER &
`FLOM LLP
`FOUR TIMES SQUARE
`NEW YORK, NY 10036 (US)
`(21) Appl. No.:
`09/882,536
`(22) Filed:
`Jun. 14, 2001
`Related U.S. Application Data
`(63) Non-provisional of provisional application No.
`60/214,470, filed on Jun. 27, 2000. Non-provisional
`of provisional application No. 60/275,790, filed on
`Mar. 14, 2001.
`
`
`
`Foreign Application Priority Data
`(30)
`Jun. 16, 2000 (DK)................................ PA 2000 OO932
`Mar. 7, 2001 (DK)................................ PA 2001 OO372
`
`Publication Classification
`
`(51) Int. Cl. .................................................. A61M 5700
`(52) U.S. Cl. .............................................................. 604/208
`
`ABSTRACT
`(57)
`An injection device for injection of Set doses of medicine
`from a cartridge, in which Syringe a dose is Set by Screwing
`a nut up along a threaded piston rod, whereby a dose Setting
`drum, which carries on its cylindrical Surface along a helix
`a Scale of which a number corresponding to the Set dose is
`shown in a window in the housing of the Syringe, and an
`injection button, which is elevated over the end of the
`Syringe, are moved axially a distance which is larger than the
`axial movement of the nut. A gear wheel gear transmission
`is established between the nut and the injection button.
`
`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
`
`Ex. 1015, p. 1 of 9
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`Patent Application Publication May 2, 2002
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`Sheet 1 of 4
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`US 2002/0052578A1
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`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
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`Ex. 1015, p. 2 of 9
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`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
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`Ex. 1015, p. 3 of 9
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`Patent Application Publication May 2, 2002 Sheet 3 of 4
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`US 2002/0052578A1
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`123 A
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`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
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`Ex. 1015, p. 4 of 9
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`Patent Application Publication May 2, 2002 Sheet 4 of 4
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`US 2002/0052578A1
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`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
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`Ex. 1015, p. 5 of 9
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`

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`US 2002/0052578 A1
`
`May 2, 2002
`
`INJECTION DEVICE
`0001. The invention relates to Syringes by which a dose
`can be set by rotating a dose Setting member and by which
`an injection button elevates from an end of the Syringe a
`distance proportional to the Set dose and wherein the Set dose
`can be injected by pressing home the injection button to its
`not elevated position.
`0002 An almost classic pen of this type is described in
`EP 327 910.
`0003. By setting a dose on this pen a tubular member
`forming an injection button is Screwed up along a threaded
`piston rod a distance corresponding to the distance Said
`piston rod must be moved to inject the set dose. The tubular
`member simply forms a nut which is during the dose Setting
`Screwed away form a Stop and which is during the injection
`pressed back to abutment with Said Stop and the force
`exerted on the button is directly transmitted to the a piston
`closing one end of an ampoule in the Syringe which ampoule
`contains the medicament to be injected. When the piston is
`pressed into the ampoule the medicament is pressed out
`through a needle mounted through a closure at the other end
`of the ampoule.
`0004. By time it has been wanted to store larger amount
`in the ampoules, typically 3 ml instead of 1.5 ml. AS it has
`not been appropriate to make the Syringe longer the ampoule
`is instead given a larger diameter, i.e. the area of the piston
`facing the medicament in the ampoule has been doubled and
`consequently the force which has to be exerted on the piston
`to provide the same pressure as previously inside the
`ampoule has been doubled. Further the distance the piston
`has to be moved to inject one unit of the medicament has
`been halved.
`0005. This development is not quite favourable, as espe
`cially users having reduced finger Strength have their diffi
`culties in pressing the injection button, a problem that is
`further increased when Still thinner needles are used to
`reduce the pain by injection. Also with quite Small move
`ments of the button it is difficult to feel whether the button
`is moved at all and by injection of one unit from a 3 ml
`ampoule the piston and consequently the injection button
`has to be moved only about 0,1 mm.
`0006 Consequently a wish for a gearing between the
`injection button and the piston has occurred So that the
`button has a larger Stroke than has the piston. By Such a
`gearing the movement of the injection button is made larger
`and the force, which has to be exerted on the injection
`button, is correspondingly reduced.
`0007. In EP 608343 a gearing is obtained by the fact that
`a dose Setting element is Screwed up along a spindle having
`a thread with a high pitch. When Said dose Setting element
`is pressed back in its axial direction the thread will induce
`a rotation of Said dose Setting element, which rotation is via
`a coupling transmitted to a driver nut with a fine pitch which
`driver nut will force a threaded not rotatable piston rod
`forward.
`0008. A similar gearing is provided in WO 99/38554
`wherein the thread with the high pitch is cut in the outer
`Surface of a dose Setting drum and is engaged by a mating
`thread on the inner Side of the cylindrical housing. However,
`by this kind of gearing relative large Surfaces are sliding
`
`over each other so that most of the transformed force is lost
`due to friction between the sliding surfaces. Therefore a
`traditional gearing using mutual engaging gear wheels and
`racks is preferred.
`0009 From WO 96/26754 is known an injection device
`wherein two integrated gear wheels engages a rack fixed in
`the housing and a rack inside a plunger, respectively. When
`the plunger is moved axially in the housing the rack inside
`this plunger can drive the first gear wheel to make the other
`integral gear wheel move along the fixed rack in the housing.
`Thereby the gear wheel is moved in the direction of the
`plunger movement but a shorter distance than is this plunger
`and this axial movement of the integrated gear wheels is via
`a housing encompassing Said gear wheels transmitted to a
`piston rod which presses the piston of an ampoule further
`into this ampoule. However, the rack inside the plunger is
`one of a number axial racks provided inside Said plunger.
`These racks alternates with untoothed recesses, which allow
`axial movement of the plunger without the first gear wheel
`being in engagement with a rack in this plunger. This
`arrangement is provided to allow the plunger to be moved in
`a direction out of the housing when a dose is set. When the
`plunger is rotated to Set a dose it is moved outward a distance
`corresponding to one unit during the part of the rotation
`where the first gear wheel passes the untoothed recess,
`thereafter the first gear wheel engages one of the racks So the
`Set unit can be injected, or the rotation can be continued to
`make the first gear wheel pass the next receSS during which
`passing the Set dose is increased by one more unit and So on
`until a dose with the wanted number of units is set.
`0010 Adisadvantage by this construction is that the teeth
`of the racks and gearwheels alternating have to be brought
`in and out of engagement with each other with the inherit
`danger of clashing. AS only a few racks Separated by
`intermediary untoothed receSS can be placed along the inner
`Surface of the plunger only few increments can be made
`during a 360° rotation.
`0011. It is an objective of the invention to provide an
`injection device, which combines the advantages of the
`devices according to the prior art without adopting their
`disadvantages and to provide a device wherein is established
`a direct gearing, i.e. a gearing by which more transforma
`tions of rotational movement to linear movement and linear
`movement to rotational movement are avoided, between the
`injection button and the piston rod.
`0012. This can be obtained by an injection device com
`prising a housing wherein a piston rod threaded with a first
`pitch is non rotatable but longitudinally displaceable guided,
`a nut engaging the thread of the piston rod which nut can be
`Screwed along the threaded piston rod away from a defined
`position in the housing to Set a dose and can be pressed back
`to Said defined position carrying the piston rod with it when
`the Set dose is injected, a dose Setting drum which can be
`Screwed outward in the housing along a thread with a Second
`pitch to lift an injection button with it up from the proximal
`end of the housing, which injection device is according to
`the invention characterised in that a gearbox is provided
`which provides a gearing between the axial movements of
`the injection button and the nut relative to the housing which
`gearing has a gearing ratio corresponding to the ratio of Said
`Second and first pitch.
`0013 In a preferred embodiment the gearing between the
`movements of the injection button and the nut is obtained by
`
`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
`
`Ex. 1015, p. 6 of 9
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`US 2002/0052578 A1
`
`May 2, 2002
`
`the gearbox comprising at least one gear wheel carried by a
`connector which projects from the gear box longitudinally
`displaceable but non rotatable relative to Said gearbox and is
`integral with the nut, a first rack integral with a first element
`of the gearbox, which element is rotational but not longitu
`dinally displaceable relative to the housing, and Second
`element carrying a Second rack projecting from Said gearbox
`longitudinally displaceable but non rotatable relative to Said
`first element and being coupled to the injection button to
`follow longitudinal movements of Said button, the at least
`one gear wheel engaging the first and the Second rack,
`respectively, and being dimensioned to provide a gearing by
`which a longitudinal movement of the Second rack is trans
`formed to a longitudinal movement of the connector with a
`gearing ratio for the mentioned longitudinal movements of
`the Second rack and the connector relative to the housing,
`which gearing ratio corresponds to the ratio of Said Second
`to Said first pitch.
`0.014.
`In such a device only the forces necessary to drive
`the dose Setting drum are transformed by a thread with a
`high pitch whereas the forces necessary to move the piston
`by injection is transmitted to Said piston through a conven
`tional gear with constantly engaging gears and racks.
`0.015 The piston rod is provided with a stop for the
`movement of the nut along the thread of Said piston rod. This
`way a dose Setting limiter is provided in the classic way,
`which involves no additional members to prevent Setting of
`a dose exceeding the amount of liquid left in the ampoule.
`0016. In the following the invention is described in
`further details with references to the drawing, wherein
`0017 FIG. 1 schematically shows a sectional view of an
`injection device according to the invention, and
`0.018
`FIG. 2 shows schematically a sectional view of the
`gear box along the line I-1 in FIG. 1,
`0.019
`FIG. 3 shows a longitudinal sectional view in the
`dose Setting part of another embodiment of an injection
`device according to the invention,
`0020 FIG. 4 shows a longitudinal sectional view per
`pendicular to the view in FIG. 3, and
`0021 FIG. 5 shows an exploded picture of the of the
`device shown in FIG. 3 and 4.
`0022. In the device shown in FIG. 1 an elongated cylin
`drical housing 1 has a partitioning wall 2 which divides the
`housing in a compartment containing a dose Setting mecha
`nism and a compartment 3 designed for the accommodation
`of a not shown ampoule. A threaded piston rod 4 has a not
`round croSS Section by which it fits through a central opening
`in the wall 2 so that the piston rod 4 can be displaced
`longitudinally through the central opening in the wall 2 but
`not rotated relative to this wall.
`0023 Concentrically with the housing 1 the wall 2 carries
`on its side turning away from the compartment 3 a tubular
`element 5 which is at a part of it adjacent to the wall 2
`provided with an outer thread 6 and which has at its free end
`a circumferential receSS 7. A ring shaped coupling element
`8 on a gear box 9 engages the receSS 7. By this coupling the
`gearbox is fixed in the housing 1 in a way that allows the
`gearbox 9 to rotate in the housing but not to be axially
`displaced relative to Said housing.
`
`In the gearbox 9 a gear wheel assembly comprising
`0024.
`two integral gear wheels is journaled on a shaft 11, which
`runs perpendicular to the longitudinal axis of the device
`between two axial connection bars 12. The connection bars
`12 project from the gearbox towards the partition wall 2 and
`are connected to a nut 13 which adjacent to the wall 2
`engages the thread of the piston rod 4. The gear wheel
`assembly comprises a gear wheel 14 with a large diameter
`engaging the teeth of a rack 15 which is guided in the gear
`box to be displaced in the longitudinal direction of the
`device, and a gear wheel 16 with a Small diameter engaging
`a rack 10 in FIG. 2 extending in the longitudinal direction
`of the device on the inner wall of the gearbox 9. The gear
`wheel 16 with the small diameter may be divided into two
`gear wheels placed on each side of the of the gear wheel 14,
`and the rack on the inner wall of the gearbox 9 may have a
`longitudinal receSS without any teeth to make room for the
`gear wheel 14.
`0025 A tubular dose setting drum 17 fitting into the
`housing 2 is at an end provided with an internal thread
`mating and engaging the outer thread 6 of the tubular
`element 5 and has at its other end a part with enlarged
`diameter forming a dose setting button 18. Due to the
`engagement with the thread 6 the dose Setting drum 17 may
`be Screwed in and out of the housing to Show a number on
`a not shown helical Scale on its outer Surface in a not shown
`window in the housing 1.
`0026. A bottom 19 in a deep cup shaped element, which
`has a tubular part 20 fitting into the dose setting drum 17 and
`encompassing the gearbox 9, forms an injection button.
`Coupling means between the dose Setting drum 17 and the
`cup shaped element ensures that rotation of the dose Setting
`drum 17 is transmitted to the cup shaped element. Further
`the inner wall of the tubular part 20 has longitudinal recesses
`22 engaged by protrusions 23 on the gearbox 9 So that
`rotation of the dose Setting drum 17 via the cup shaped
`element is transmitted to the gearbox 9.
`0027. At the edge of the open end of the cup shaped
`element a rosette of V-shaped teeth are provided, which teeth
`engage a corresponding rosette of V-shaped teeth 24 on a
`ring 25 which is pressed against the edge of the cup shaped
`element by a Spring 26 which is compressed between a not
`toothed side of the ring 25 and a round going shoulder 27 on
`the inner wall of the dose setting drum 17 at an inner end of
`the inner thread of this drum. The ring is provided with an
`inner receSS, which is engaged by a longitudinal rib 28 on the
`tubular element 5 so that the ring 25 can be displaced in the
`axial direction of the device but cannot be rotated relative to
`the housing 1. Thereby a click coupling is established which
`makes a click noise when the V-shaped teeth at the edge of
`the cup shaped element by rotation of this element rides over
`the V-shaped teeth of the ring 25.
`0028. A head 29 on the projecting end of the rack 15 is
`with a play fixed at the bottom of the cup shaped element
`between the bottom 19 forming the injection button and an
`inner wall 30 near this bottom. The rack is fixed in a position
`with its head pressed against the wall 30 by a spring 31
`between the bottom 19 and the head 29.
`0029. To set a dose the dose setting button 18 is rotated
`to screw the dose-setting drum 17 up along the thread 6. Due
`to the coupling 21 the cup shaped element will follow the
`rotation of the dose-setting drum 17 and will be lifted with
`
`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
`
`Ex. 1015, p. 7 of 9
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`US 2002/0052578 A1
`
`May 2, 2002
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`this drum up from the end of the housing 1. By the rotation
`of the cup shaped element the V-shaped teeth 24 at the edge
`of its open end will ride over the V-shaped teeth of the non
`rotatable ring 25 to make a click Sound for each unit the dose
`is changed. A too high Set dose can be reduced by rotating
`the dose setting button 18 in the opposite direction of the
`direction for increasing the dose. When the dose Setting
`drum is Screwed up along the thread 6 on the tubular element
`5 the ring 25 will follow the dose setting drum in its axial
`movement as the Spring 26 is Supported on the shoulder 27.
`The spring will keep the V-shaped teeth of the ring 25 and
`the cup shaped element in engagement and maintain in
`engagement the coupling 21, which may comprise A-shaped
`protrusions 32 on the cup shaped element engaging
`A-shaped recesses in an inner ring 33 in the dose Setting
`button 18.
`0030) The rotation of the dose setting button 18 and the
`cup shaped element is further transmitted to the gearbox 9
`through the protrusions 23 on this gearbox engaging the
`longitudinal recesses 22 in the inner wall of the tubular part
`20 of said cup shaped element. The rotation of the gearbox
`25 is through the connection bars 12 transmitted to the nut
`13, which is this way screwed up along the thread of the
`piston rod 4 and lifted away from its abutment with the wall
`2 when a dose it set. As the dose is set by moving the nut 13
`on the very piston rod which operates the piston in the not
`shown ampoule in the compartment 3 a dose Setting limiter,
`which ensures that the size of the Set dose does not exceed
`the amount of medicament left in the ampoule, can easily be
`established by providing the piston rod 4 with a stop 35
`which limits the movement of the nut 13 up along the piston
`rod 4.
`0031. Due to the confinement of the head 29 in the space
`between the bottom 19 and the wall 30 of the cup shaped
`element, the rack 15 is drawn with the injection button
`outward. Also the axial movement of the nut 13 relative to
`the housing 1 will be transmitted to the gear wheel assembly
`through the connection bars 12 and this movement will
`through the gearbox induce an outward movement of the
`rack 15. This induced outward movement have to be the
`Same as the outward movement induced by outward move
`ment of the injection button. This is obtained by dimension
`ing the gear wheels of the gearbox 9 So that the gear ratio for
`the movements of the connection bars 12 and the rack 15
`relative to the housing corresponds to the ratio of the pitches
`for the thread on the piston rod and for the thread 6 for the
`longitudinal movement of the dose Setting drum 17.
`0.032 To inject a set dose the injection button is pressed
`by pressing on the bottom 19. In the initial phase of the
`pressing the Spring 31 is compressed where after the press
`ing force is directly transmitted to the head 29 of the rack 15
`and this way to the rack 15 itself. Through the gear box 9 the
`force is transformed and is transmitted through the connec
`tion bars 12 to the nut 13 which will press the piston rod 4
`into the compartment 3 until the dose-setting drum 17 abuts
`the wall 2.
`0033. During the initial phase of the movement of the
`injection button the A-shaped protrusions 32 on the cup
`shaped element will be drawn out of their engagement with
`the A-shaped recesses in the ring 33. The dose-Setting drum
`17 can now rotate relative to the injection button and will do
`So when the A-shaped protrusions 32 press against a shoul
`
`der 34 at the bottom of the dose setting button 18. Only a
`force Sufficient to make the dose Setting drum rotate to Screw
`itself downward along the thread 6 is necessary as the force
`necessary to make the injection is transmitted to the piston
`rod 4 through the gearbox 9. A helical reset spring 36
`concentric with the dose Setting drum can be mounted at the
`lower end of this drum and can have one end anchored in the
`dose setting drum 17 and the other end anchored in the wall
`2. During Setting of a dose this spring may be tighter coiled
`So that on the dose Setting drum it exerts a torque approxi
`mately corresponding to the torque necessary to overcome
`the friction in the movement of the dose Setting drum along
`the thread 6 so that the force which the user have to exert on
`the injection button is only the force necessary to drive the
`piston rod into an ampoule to inject the Set dose.
`0034.
`It shall be noticed that use of only one size gear
`wheel which engages as well the rack 15, which is movable
`relative to the gearbox 9, as the rack 10, which is unmovable
`relative to the gear box, provides a gearing ratio of 2:1 for
`the longitudinal movement relative to the Syringe housing 1
`for the movable rack 15 and the connector 12, which carries
`the shaft 11 of the gear wheel.
`0035 FIGS. 3 and 4 shows a preferred embodiment
`wherein only one size gear wheel is used and wherein
`elements corresponding to elements in FIG. 1 and 2 are
`given the same references as these elements with a prefixed
`66 1.
`0036 For manufacturing reasons minor changes are
`made. So the partitioning wall 102 and the tubular element
`105 are made as two parts which are by the assembling of
`the device connected to each other to make the assembled
`parts act as one integral part. The same way the dose Setting
`drum 117 and the dose setting button 118 are made as two
`parts, which are fixed firmly together.
`0037. A circumferential recess 107 is provided as an
`outer recess at the free end of the tubular part 105 and a ring
`shaped coupling element is provided as an inner bead 108 on
`the gearbox element 109 which bead engages the recess 107
`to provide a rotatable but not axially displaceable connection
`between the tubular part 105 and the gearbox.
`0038 A tubular element 120 having ridges 122 which
`engages recesses 123 on the gearbox is at its upper end
`closed by a button 119 from which a force provided by
`pressing this button is transmitted to the tubular element
`120.
`0039. The gearbox is formed by two shells, which
`together form a cylinder fitting into the tubular element
`where the shells are guided by the engagement between the
`ridges 122 and the recesses 123. Racks 110 and 115 are
`provided along edges of the shells facing each other. One
`shell forming the gearbox part 109 is provided with the inner
`bead 108, which engages the circumferential recess 107 at
`the end of the central tubular part 105 and carries the rack
`110. The other shell is axially displaceable in the tubular
`element 120 and forms the rack 115. At its outer end
`projecting from the gearbox the Shell carrying the rack 115
`is provided with a flange 140 which is positioned in a cut out
`141 in the end of the tubular element 120 carrying the button
`119 so that this button and the tubular element 120 can be
`moved So far inward in the device that the engagement of the
`teeth 132 and 133 can be released before the button 119
`abuts the flange 140.
`
`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
`
`Ex. 1015, p. 8 of 9
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`US 2002/0052578 A1
`
`May 2, 2002
`
`0040. A tubular connection element 112 connects the
`threaded piston rod 104 with the gearbox. At its end engag
`ing the piston rod 104 the connection element has a nut 113
`with an internal thread mating the external thread of the
`piston rod. At its end engaging the gear box the connection
`element is provided with two pins 111 projecting perpen
`dicular to the longitudinal axis of the connection element
`112 at each Side of this element. Each pin 111 carries a gear
`wheel 114 which is placed between and engages the two
`racks 110 and 115. This way the connection element 112 will
`be rotated with the gear box but can be displaced axially
`relative to said gear box when the racks 110 and 115 are
`moved relative to each other. In practice it will be the rack
`115, which is moved relative to the gearbox element 109 and
`the housing and will by the shown construction result in a
`movement of the connection element 112 relative to housing
`a distance which is half the distance which the rack 115 is
`moved. A ring 125 which is at its periphery provided with a
`rosette of teeth 124 and has a central bore fitting over the
`central tube in the housing 101 so that this ring 125 can be
`axially displaced along said central tube 105, but internal
`ridges 128 in the central bore of the ring 125 engages
`longitudinal recesses 137 in the central tube to make the ring
`non rotatable in the housing So that a rosette of teeth at the
`edge of the tubular element 120 can click over the teeth 124
`of the ring when Said tubular element is rotated together with
`the dose setting drum 117. A spring 126 working between
`the ring 125 and an internal shoulder 127 provided in the
`dose setting drum 117 makes the ring follow the tubular
`element 120 when this element with the dose setting drum
`is moved longitudinally in the housing. To make the dose
`Setting drum easy rotatable, especially when Said dose
`Setting drum is pressed inward in the housing, a roller
`bearing having an outer ring 142 Supported by the shoulder
`127 and an inner ring 143 Supporting a pressure bushing 144
`which supports the spring 126. By the provision of this
`Smooth running Support only very Small axial forces are
`needed to rotate the dose setting drum 117 back to its zero
`position when a Set dose is injected. This Solution replaces
`the provision of a reset spring as the spring 36 in FIG.1. The
`bearing is shown as a radial bearing but can be replaced by
`an axial bearing
`1. An injection device comprising a housing wherein a
`piston rod with a thread having a first pitch is non rotatable
`
`but longitudinally displaceable guided, a nut engaging the
`thread of the piston rod which nut can be Screwed along the
`threaded piston rod away from a defined position in the
`housing to Set a dose and can be pressed back to Said defined
`position carrying the piston rod with it when the Set dose is
`injected, a dose Setting drum which can be Screwed outward
`in the housing along a thread with a Second pitch to lift an
`injection button with it up from an end of the housing,
`characterised in that a gearbox is provided which provides a
`gearing between the axial movements of the injection button
`and the nut relative to the housing which gearing has a
`gearing ratio corresponding to the ratio of Said Second and
`first pitch.
`2. An injection device according to claim 1, characterised
`in that the gearing between the movements of the injection
`button and the nut is obtained by the gearbox comprising at
`least one gear wheel carried by a connector which projects
`from the gear box longitudinally displaceable but non rotat
`able relative to Said gearbox and is integral with the nut, a
`first rack integral with a first element of the gearbox, which
`element is rotational but not longitudinally displaceable
`relative to the housing , and Second element carrying a
`Second rack projecting from Said gearbox longitudinally
`displaceable but non rotatable relative to said first element
`and being coupled to the injection button to follow longi
`tudinal movements of Said button, the at least one gear wheel
`engaging the first and the Second rack, respectively, and
`being dimensioned to provide a gearing by which a longi
`tudinal movement of the Second rack is transformed to a
`longitudinal movement of the connector with a gearing ratio
`for the mentioned longitudinal movements of the Second
`rack and the connector relative to the housing, which gearing
`ratio corresponds to the ratio of Said Second to Said first
`pitch.
`3. An injection device according to claim 2, characterised
`in that the gearing between the movements of the injection
`button and the nut has the gearing ratio 2:1 obtained by one
`and the Same gear wheel engaging both the first and the
`Second rack.
`4. Device according to any one of the claims 1, 2 or 3,
`characterized in that the piston rod is provided with a stop
`for the movement of the nut along the thread of Said piston
`rod.
`
`PFIZER, INC. v. SANOFI-AVENTIS DEUTSCHLAND GMBH
`
`Ex. 1015, p. 9 of 9
`
`