Medication dispensing apparatus with spring-driven locking feature enabled by administration of final dose

• US 7,517,334 B2
• Filed: 03/25/2005
• Issued: 04/14/2009
• Est. Priority Date: 03/30/2004
• Status: Active Grant

• Current Assignee: Eli Lilly and Company
• Original Assignee: Eli Lilly and Company
• Inventors: Row, Gordon Davidson, Judson, Jared Alden, Jacobs, Alexander Thomas
• Primary Examiner(s): Sirmons; Kevin C
• Assistant Examiner(s): CARPENTER, WILLIAM R
• Application Number:
  US10/598,987
• Publication Number:
  US 20070197976A1
• Time in Patent Office: 1,481 Days
• Field of Search: 604/156, 604/131, 604/141, 604/181, 604/132, 604/218, 604/187, 604/201, 604/264, 604/208, 604/211, 604/209
• US Class Current: 604/110
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/31555 by purely axial movement of dose setting member, e.g. during setting or filling of a syringe
• CPC Class Codes: A61M 5/31558 using scaling up or down transmissions, e.g. gearbox
• CPC Class Codes: A61M 5/3157 Means providing feedback signals when administration is completed A61M5/20 takes precedence
• CPC Class Codes: A61M 5/31571 Means preventing accidental administration for automatic syringes A61M5/20
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button
• CPC Class Codes: A61M 5/502 for blocking the piston

Abstract

A medication dispensing apparatus with a spring-driven locking feature includes a drive member movable in a distal direction within a housing, and a fluid container with a piston that is advanceable by the drive member (60) when such drive member is moved distally by a driving means. The apparatus includes a latching element (180) having a skid (190) that is slidable along a surface of the drive member as the drive member passes distally during advancement. The drive member is arranged with the skid so as to maintain a latching lip of the latching element against a spring force in a first position free of the driving means during dose preparing and injecting prior to a final dose administration. The skid-engaging surface shifts distally of the skid such that the skid passes beyond a proximal end of that surface upon administration of a final dose, whereby the latching lip is urged by the spring force from the first position to a second position to physically lock the driving means to prevent further dose preparing and injecting.

Claims

1. A medication dispensing apparatus comprising:

a housing;

a drive member within said housing and movable in a distal direction;

a fluid container defining a medicine-filled reservoir with a movable piston at one end and an outlet at the other end, said piston engageable by said drive member to be advanced toward said outlet a distance equal to a distal movement of said drive member when said drive member is moved distally;

a plunger element;

a gear set including first and second pinions, said gear set pivotal on said plunger element and shiftable proximally and distally with the plunger element;

a first rack engaged with said first pinion and axially stationary within said housing;

a second rack engaged with said second pinion and movable within said housing on a piece clutchably connected to said drive member;

a latching element including a latching lip and a skid;

said drive member including an axially extending, skid-engaging surface along which said skid is slidable as said drive member passes distally during advancement during plunger element shifting in the distal direction, said skid-engaging surface having an axial length and a proximal end, said drive member along said axial length structured and arranged with said skid so as to maintain said latching lip against a spring force in a first position free of a latchable element disposed on said plunger element during dose preparing and injecting prior to a final dose administration; and

wherein said skid-engaging surface shifts distally of said skid such that said skid passes beyond the proximal end upon administration of a final dose allowing said latching lip to be urged by said spring force from said first position to a second position for engagement with said latchable element to physically lock said plunger element to prevent further dose preparing and injecting.

2. The medication dispensing apparatus of claim 1 wherein said proximal end of said skid-engaging surface comprises a proximal end of said drive member.

3. The medication dispensing apparatus of claim 1 wherein said skid is disposed distally of said latching lip.

4. The medication dispensing apparatus of claim 1 wherein said skid comprises a blade shape member that extends axially, and wherein said latching lip comprises a transversely extending flange.

5. The medication dispensing apparatus of claim 1 wherein said latchable element comprises a ramped distal face over which said latching lip is cammable to reach a latching engagement with said latchable element.

6. The medication dispensing apparatus of claim 1 wherein said latching element is axially fixed to said housing by at least one flange fit into a slot provided in said housing.

7. The medication dispensing apparatus of claim 1 wherein said spring force acting on said latching element comprises a resiliency of said latching element tending to return said latching lip to a neutral arrangement.

8. The medication dispensing apparatus of claim 7 wherein said latching element comprises a one piece metal stamping.

9. The medication dispensing apparatus of claim 1 wherein said skid-engaging surface is smooth.

10. The medication dispensing apparatus of claim 1 wherein said latching lip comprises a rim along an opening through which a latchable element extends to reach a latching engagement with said latching element.