Medication dispensing apparatus configured for rotate to prime and pull/push to inject functionality

Abstract

A medication dispensing apparatus having a manually operable plunger axially shiftable relative to the apparatus housing. The plunger is pullable relative to the housing in a proximal direction to cock the apparatus, and when the plunger is then manually pushed back toward the housing, a piston within a medicine container of the apparatus is shifted to force medication from a needle assembly at the distal end of the apparatus. The medication dispensing apparatus also includes a priming mechanism which is operated by rotating an externally accessible driver portion to prime the apparatus for use, which priming can be performed whether or not the apparatus is in a cocked state.

We claim:  
     
         1 . A medication dispensing apparatus comprising: 
 a housing;    a fluid container mounted to said housing, said container defining a medicine-filled reservoir;    a needle assembly removably attached to a distal end of said fluid container to have an injection needle of said needle assembly in flow communication with said reservoir;    a drive mechanism for dispensing a dose of medicine from said reservoir through said injection needle, said drive mechanism including a plunger manually pullable relative to said housing in a proximal direction to shift the apparatus from a ready state to a cocked state, said plunger manually pushable relative to said housing in a distal direction to force medicine out said injection needle while returning the apparatus from the cocked state to the ready state;    a priming mechanism for priming said injection needle with medicine from said reservoir, said priming mechanism including a drive portion external to said housing to be manually rotatable relative to said housing; and    a rotation controlling mechanism that permits manual rotation of said priming mechanism drive portion in a first direction and as far as necessary to achieve priming, and that prevents manual rotation of said priming mechanism drive portion in a direction opposite to said first direction.    
     
     
         2 . The medication dispensing apparatus of  claim 1  wherein said priming mechanism drive portion is adjacent to and operable independently of said plunger.  
     
     
         3 . The medication dispensing apparatus of  claim 1  wherein said rotation controlling mechanism comprises a ratchet pawl and ratchet teeth acting between said housing and said priming mechanism.  
     
     
         4 . The medication dispensing apparatus of  claim 1  wherein said priming mechanism is configured to achieve priming whether the apparatus is in the cocked state or the ready state, and without altering the dose to be dispensed by the drive mechanism if the apparatus is in the cocked state.  
     
     
         5 . The medication dispensing apparatus of  claim 1  wherein said priming mechanism comprises a threaded portion and a rotatably fixed drive screw, said threaded portion internal to said housing and rotatably fixed relative to said priming mechanism drive portion, said threaded portion in engagement with external threading of said drive screw, whereby rotation of said priming mechanism drive portion rotates said threaded portion to force said drive screw to translate distally and force medication from the reservoir.  
     
     
         6 . The medication dispensing apparatus of  claim 5  wherein said threaded portion comprises a plurality of radially resilient fingers integrally formed with said priming mechanism drive portion.  
     
     
         7 . The medication dispensing apparatus of  claim 1  wherein said drive mechanism comprises a follower and a rotatably fixed drive screw, said plunger connected to said follower to be axially fixed together while allowing relative rotation therebetween, said follower including a threaded portion internal to said housing and in engagement with external threading of said drive screw.  
     
     
         8 . The medication dispensing apparatus of  claim 7  wherein said threaded portion of said follower comprises a plurality of radially resilient fingers.  
     
     
         9 . The medication dispensing apparatus of  claim 1  wherein said fluid container comprises a disposable cartridge removable from the apparatus for replacement, and further comprising means for resetting said drive mechanism to reuse the medication dispensing apparatus with a replacement cartridge.  
     
     
         10 . A medication dispensing apparatus comprising: 
 a housing;    a fluid container mounted to said housing, said container defining a medicine-filled reservoir;    a needle assembly removably attached to a distal end of said fluid container to have an injection needle of said needle assembly in flow communication with said reservoir;    a drive mechanism for dispensing a dose of medicine from said reservoir through said injection needle, said drive mechanism including a plunger manually pullable relative to said housing in a proximal direction to shift the apparatus from a ready state to a cocked state, said plunger manually pushable relative to said housing in a distal direction to force medicine out said injection needle while returning the apparatus from the cocked state to the ready state;    a priming mechanism for priming said injection needle with medicine from said reservoir by manually rotating an element other than said plunger; and    wherein said priming mechanism is operable to effect priming whether the apparatus is in the cocked state or the ready state, and without altering the dose to be dispensed by the drive mechanism if the apparatus is in the cocked state.    
     
     
         11 . A medication dispensing apparatus comprising: 
 a housing;    a fluid container mounted to said housing, said container defining a medicine-filled reservoir with a movable piston at a proximal end;    a needle assembly removably attached to a distal end of said fluid container to have an injection needle of said needle assembly in flow communication with said reservoir;    a drive member axially extending within said housing and movable distally to advance said movable piston toward said injection needle, said drive member, along an axial cross-section, having a series of axially spaced projections;    a follower portion engagable with said projections and having a resilient construction;    a plunger operably connected to said follower portion and manually pullable in a proximal direction to shift said plunger from a first position to a second position, and manually pushable in a distal direction to shift said plunger from said second position to said first position;    said follower portion being axially shiftable by movement of said plunger in said proximal and distal directions, wherein said follower portion bends radially outward and axially slides over at least one projection of said drive member when said plunger is pulled proximally to shift from said first position to said second position, and wherein said follower portion, by abutment with a projection of said drive member over which said follower portion previously slid, advances said drive member distally when said plunger is pushed distally from said second position to said first position; and    a priming driver operably connected to said drive member and including a drive portion external to said housing which is manually rotatable independently of said plunger to axially advance said drive member to prime said injection needle with medicine from said reservoir.    
     
     
         12 . The medication dispensing apparatus of  claim 11  wherein said drive member is a screw with external threading, and wherein said series of axially spaced projections comprise passes of said threading of said drive screw.  
     
     
         13 . The medication dispensing apparatus of  claim 11  wherein said fluid container comprises a disposable cartridge removable from the apparatus for replacement, and further comprising means for resetting said drive member to reuse the medication dispensing apparatus with a replacement cartridge.  
     
     
         14 . The medication dispensing apparatus of  claim 13  wherein said resetting means comprises a camming element movable within said housing between a ready position and a camming position, wherein movement of said camming element from said ready position to said camming position forces said follower portion to bend radially outward to disengage said follower portion from said projections.  
     
     
         15 . The medication dispensing apparatus of  claim 14  further comprising a biasing member urging said camming element from said ready position to said camming position, and wherein said camming element is operably connectable to said fluid container such that mounting of said fluid container to said housing automatically shifts said camming element from said camming position to said ready position against the urging of said biasing member, and such that dismounting said fluid container from said housing allows said biasing member to automatically shift said camming element from said ready position to said camming position.  
     
     
         16 . The medication dispensing apparatus of  claim 13  further comprising means for ensuring a complete resetting of said drive member, said resetting ensuring means comprising at least one over-center spring mechanism engagable with said drive member.  
     
     
         17 . A medication dispensing apparatus comprising: 
 a housing;    a fluid container mounted to said housing, said container defining a medicine-filled reservoir with a movable piston at one end and an outlet at the other end;    a drive screw with external threading, said drive screw axially extending within said housing and movable distally to advance said movable piston toward said outlet;    at least one anti-rotation member operably engaging said drive screw to prevent rotation of said drive screw within said housing;    a priming driver axially retained relative to said housing and having a first portion and a second portion, said first portion internal to said housing and in threaded engagement with said drive screw, said second portion external to said housing to be manually rotatable, whereby rotation of said second portion rotates said first portion to force said drive screw to translate distally;    a follower axially movable relative to said priming driver and rotatably fixed thereto, said follower including a portion internal to said housing and in threaded engagement with said drive screw;    a plunger axially movable relative to said housing between a distal position and a proximal position, said plunger including a manually graspable grip portion which is pullable proximally to move said plunger from said distal position to said proximal position, said plunger connected to said follower to allow relative rotation therebetween and to shift said follower axially when said plunger moves back and forth between said distal and proximal positions; and    wherein each of said follower portion and said priming driver first portion comprises a resilient construction, whereby when said plunger is pulled from said distal position to said proximal position to shift said follower proximally, said follower portion slides over said threading of said drive screw that is being axially retained by engagement with said priming driver first portion, and whereby when said plunger is pushed from said proximal position to said distal position to shift said follower distally, said priming driver first portion slides over said threading of said drive screw that is being axially advanced by engagement with said follower portion.    
     
     
         18 . The medication dispensing apparatus of  claim 17  wherein said priming driver first portion comprises a plurality of axially extending fingers angularly spaced around a circumference of said drive screw.  
     
     
         19 . The medication dispensing apparatus of  claim 18  wherein said follower portion comprises a plurality of angularly spaced, axially extending fingers that interfit with said plurality of fingers of said priming driver first portion to rotationally key said follower with said priming driver.  
     
     
         20 . The medication dispensing apparatus of  claim 19  wherein at least one of said plurality of fingers of said priming driver first portion comprises a projecting stop that abuts at least one of said plurality of fingers of said follower portion to limit distal travel of said follower during use.  
     
     
         21 . The medication dispensing apparatus of  claim 17  wherein said priming driver comprises a radially inwardly extending ledge that abuts a radially outwardly projecting shoulder of said follower to limit proximal travel of said follower during use.  
     
     
         22 . The medication dispensing apparatus of  claim 17  wherein said priming driver comprises one of a ratchet pawl and ratchet teeth, and said housing comprises the other of the ratchet pawl and ratchet teeth, said ratchet pawl and ratchet teeth interfitting to prevent rotation of said priming driver within said housing in a direction that would force said drive screw to translate proximally.  
     
     
         23 . The medication dispensing apparatus of  claim 17  wherein said at least one anti-rotation member comprises a pair of diametrically opposed prongs that radially inwardly project from an interior wall of said housing, said prongs fitting within a pair of longitudinally extending slots formed in said threading of said drive screw.  
     
     
         24 . The medication dispensing apparatus of  claim 17  wherein said fluid container comprises a disposable cartridge removable from the apparatus for replacement, and further comprising means for resetting said drive screw to reuse the medication dispensing apparatus with a replacement cartridge.  
     
     
         25 . The medication dispensing apparatus of  claim 24  wherein said resetting means comprises a camming element movable within said housing between a ready position and a camming position, wherein movement of said camming element from said ready position to said camming position forces said follower portion and said priming driver first portion to bend radially outward to disengage said follower portion and said priming driver first portion from threaded engagement with said drive screw.  
     
     
         26 . The medication dispensing apparatus of  claim 25  wherein said camming element comprises an inner ring, an outer ring and a plurality of arms connecting said inner ring and said outer ring, said inner ring positioned radially between said drive screw and both said follower portion and said priming driver first portion, said outer ring positioned within said housing radially outward of said follower portion and said priming driver first portion, and said connecting arms extending through angular gaps between said follower portion and said priming driver first portion.  
     
     
         27 . The medication dispensing apparatus of  claim 26  wherein said outer ring is located distally of said inner ring.  
     
     
         28 . The medication dispensing apparatus of  claim 25  further comprising a biasing member urging said camming element from said ready position to said camming position, and wherein said camming element is operably connectable to said fluid container such that mounting of said fluid container to said housing automatically shifts said camming element from said camming position to said ready position against the urging of said biasing member, and such that dismounting said fluid container from said housing allows said biasing member to automatically shift said camming element from said ready position to said camming position.  
     
     
         29 . The medication dispensing apparatus of  claim 28  wherein said camming element is operably connectable to said fluid container by a separate interface member disposed within said housing distally of said camming element, said interface member comprising a cartridge abutting surface and a camming element abutting surface.  
     
     
         30 . The medication dispensing apparatus of  claim 25  wherein said camming element comprises a grip portion and a camming portion, said grip portion external to said housing and connected to said camming portion internal to said housing.  
     
     
         31 . The medication dispensing apparatus of  claim 30  wherein said camming element translates axially when shifted from said ready position to said camming position.  
     
     
         32 . The medication dispensing apparatus of  claim 24  further comprising means for ensuring a complete resetting of said drive screw.  
     
     
         33 . The medication dispensing apparatus of  claim 32  wherein said resetting ensuring means comprises at least one over-center spring mechanism engagable with said drive screw.  
     
     
         34 . The medication dispensing apparatus of  claim 33  wherein said at least one over-center spring mechanism comprises at least one spring loaded pivotable member including a tip portion that slides within a longitudinally extending slot formed in said threading of said drive screw, and wherein said pivotable member automatically pivots from a first position to a second position when said tip portion inserts within a recess formed in said slot and acts against a ledge surface of said drive screw which defines said recess.  
     
     
         35 . The medication dispensing apparatus of  claim 34  wherein said ledge surface comprises a surface defining a throughbore through said drive screw.  
     
     
         36 . The medication dispensing apparatus of  claim 34  wherein said at least one spring loaded pivotable member comprises first and second pivotable members each including a tip portion that slides within a different longitudinally extending slot formed in said threading of said drive screw.  
     
     
         37 . A medication dispensing apparatus ( 20 ) comprising: 
 a housing ( 60 );    a fluid container ( 28 ,  48 ) mounted to said housing, said container defining a medicine-filled reservoir ( 50 );    a needle assembly ( 38 ) removably attached to a distal end of said fluid container to have an injection needle ( 40 ) of said needle assembly in flow communication with said reservoir;    a drive mechanism for dispensing a dose of medicine from said reservoir through said injection needle, said drive mechanism including a plunger ( 160 ) manually pullable relative to said housing in a proximal direction to shift the apparatus from a ready state to a cocked state, said plunger manually pushable relative to said housing in a distal direction to force medicine out said injection needle while returning the apparatus from the cocked state to the ready state;    a priming mechanism for priming said injection needle with medicine from said reservoir, said priming mechanism including a drive portion ( 102 ) external to said housing to be manually rotatable relative to said housing;    characterized in that said medication dispensing apparatus further comprises a rotation controlling mechanism ( 68 ,  106 ,  108 ) that permits manual rotation of said priming mechanism drive portion in a first direction and as far as necessary to achieve priming, and that prevents manual rotation of said priming mechanism drive portion in a direction opposite to said first direction.    
     
     
         38 . The medication dispensing apparatus ( 20 ) of  claim 37  wherein said priming mechanism drive portion is adjacent to and operable indepedently of said plunger.  
     
     
         39 . The medication dispensing apparatus ( 20 ) of  claim 37  wherein said rotation controlling mechanism comprises a ratchet pawl ( 106 ,  108 ) and ratchet teeth ( 68 ) acting between said housing and said priming mechanism.  
     
     
         40 . The medication dispensing apparatus ( 20 ) of  claim 37  wherein said priming mechanism is configured to achieve priming whether the apparatus is in the cocked state or the ready state, and without altering the dose to be dispensed by the drive mechanism if the apparatus is in the cocked state.  
     
     
         41 . The medication dispensing apparatus ( 20 ) of  claim 37  wherein said priming mechanism comprises a threaded portion ( 128 ,  132 ) and a rotatably fixed drive screw ( 80 ), said threaded portion internal to said housing and rotatably fixed relative to said priming mechanism drive portion, said threaded portion in engagement with external threading ( 84 ) of said drive screw, whereby rotation of said priming mechanism drive portion rotates said threaded portion to force said drive screw to translate distally and force medication from the reservoir.  
     
     
         42 . The medication dispensing apparatus ( 20 ) of  claim 41  wherein said threaded portion comprises a plurality of radially resilient fingers ( 128 ) integrally formed with said priming mechanism drive portion.  
     
     
         43 . The medication dispensing apparatus ( 20 ) of  claim 37  wherein said drive mechanism comprises follower ( 140 ) and a rotatably fixed drive screw ( 80 ), said plunger connected to said follower to be axially fixed together while allowing relative rotation therebetween, said follower including a threaded portion ( 146 ,  148 ) internal to said housing and in engagement with external threading ( 84 ) of said drive screw.  
     
     
         44 . The medication dispensing apparatus ( 20 ) of  claim 43  wherein said threaded portion of said follower comprises a plurality of radially resilient fingers ( 146 ).  
     
     
         45 . The medication dispensing apparatus ( 220 ) of  claim 37  wherein said fluid container comprises a disposable cartridge ( 238 ) removable from the apparatus for replacement, and further comprising means ( 385 ,  387 ,  389 ) for resetting said drive mechanism to reuse the medication dispensing apparatus with a replacement cartridge.