Syringe with tiltable nut for quick piston disengagement

• US 5,961,496 A
• Filed: 06/09/1998
• Issued: 10/05/1999
• Est. Priority Date: 06/17/1997
• Status: Expired due to Fees

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Andersen, Henrik, Nielsen, Preben Broskov
• Primary Examiner(s): Coggins, Wynn Wood
• Assistant Examiner(s): KENNEDY, SHARON E
• Application Number:
  US09/094,311
• Time in Patent Office: 483 Days
• Field of Search: 604/207-211, 604/232, 604/186, 604/224, 604/228, 604/181, 604/225, 604/220, 411/433, 411/437, 411/950, 222/391
• US Class Current: 604/209
• CPC Class Codes: A61M 2005/14573 with a replaceable reservoir for quick connection/disconnection with a driving system
• CPC Class Codes: A61M 2005/31518 designed to reduce the overall size of an injection device, e.g. using flexible or pivotally connected chain-like rod members
• 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 5/3146 Priming, e.g. purging, reducing backlash or clearance
• CPC Class Codes: A61M 5/315 Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
• 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 5/31525 Dosing burettes, pipettes B01L3/02
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
• CPC Class Codes: A61M 5/31551 including axial movement of dose setting member
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/31556 Accuracy improving means
• CPC Class Codes: A61M 5/31558 using scaling up or down transmissions, e.g. gearbox
• CPC Class Codes: A61M 5/31563 interacting with a displaceable stop member
• CPC Class Codes: A61M 5/31571 Means preventing accidental administration for automatic syringes A61M5/20
• CPC Class Codes: A61M 5/31575 using scaling up or down transmissions, e.g. gearbox
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir
• CPC Class Codes: A61M 5/31595 Pre-defined multi-dose administration by repeated overcoming of means blocking the free advancing movement of piston rod, e.g. by tearing or de-blocking
• CPC Class Codes: B05C 17/0113 the piston rod being flexible or articulated B05C17/0109 takes precedence

Abstract

In a syringe dosing mechanism a threaded spindle (1) and a nut (3) cooperates so that relative rotation thereof moves the nut (3) along the spindle (1). The nut (3) has two intersecting bores (12, 15). The first bore (15) has an inner thread (7) matching the outer thread (2) of the spindle (1) and the second bore (12) is smooth and fits slidingly over the spindle (1). The nut (3) is tiltable between a first and a second position. In the first position the threaded bore (15) is coaxial with the spindle (1) and in the second position the smooth bore (12) is coaxial with the spindle (1). The nut (3) is at a first side hinged to a piston rod (6)so that exertion of a force by the nut (3) on the piston rod (6) in a direction (10) by which an injection is performed will tilt said nut (3) into its first position. A piston withdrawal member acts at a second side of said nut diametrically opposite said first side so that the nut (3) is tilted to its second position when the withdrawal member applies a force (13) to said nut (3).

Claims

1. A syringe comprising a housing including a cartridge holder for receiving a cartridge of the type having a piston, and a dosing mechanism by which a dose may be set and subsequently injected by successively advancing the piston when such a cartridge is mounted in the cartridge holder, said dosing mechanism comprising a spindle having an axis and an outer thread, and a nut member cooperating with the spindle, wherein said spindle and nut member are mounted within said housing so as to be rotatable relative to one another, wherein the nut has a first bore and a second bore which intersect and form an angle with each other, wherein said first bore has an inner thread matching the outer thread of the spindle such that rotation of the spindle relative to the nut member causes the axial position of the nut member relative to the spindle to change, the position of the nut member on the spindle defining how far the piston is advanced during the injection, wherein said second bore is smooth and fits slidingly about the outer thread of said spindle, wherein the nut member is tiltable between a first position, in which the first bore is coaxial with the spindle, and a second position, in which the second bore is coaxial with the spindle, such that said nut member can be moved into its first position during dose setting and injection operations and into its second position when it is desired to move said nut member along the spindle without rotating the spindle, and wherein said syringe further comprises a piston withdrawal member which acts on the nut member at a location such that the nut member is tilted to its second position when a piston rod withdrawal force is applied to said nut member.

2. A syringe comprising a housing including a cartridge holder for receiving a cartridge of the type having a piston, and a dosing mechanism by which a dose may be set and subsequently injected by successively advancing the piston when such a cartridge is mounted in the cartridge holder, said dosing mechanism comprising a spindle having an axis and an outer thread, and a nut member cooperating with the spindle, wherein said spindle and nut member are mounted in said housing so as to be rotatable relative to one another, wherein the nut has a first bore and a second bore which intersect and form an angle with each other, wherein said first bore has an inner thread matching the outer thread of the spindle such that rotation of the spindle relative to the nut member causes the axial position of the nut member relative to the spindle to change, wherein said spindle and said nut member are both axially moveable within said housing, in a direction towards said cartridge holder, to inject a set dose, the position of the nut member on the spindle defining how far the piston is advanced during the injection, wherein said second bore is smooth and fits slidingly about the outer thread of said spindle, and wherein the nut member is tiltable between a first position, in which the first bore is coaxial with the spindle, and a second position, in which the second bore is coaxial with the spindle, such that said nut member can be moved into its first position during dose setting and injection operations and into its second position when it is desired to move said nut member along the spindle without rotating the spindle.

3. A syringe comprising a housing including a cartridge holder for receiving a cartridge of the type having a piston, a piston rod having one end arranged to contact the piston of such a cartridge when the cartridge is mounted in the cartridge holder, and a dosing mechanism by which a dose may be set and subsequently injected by successively advancing said piston rod into such cartridge, said dosing mechanism comprising a spindle having an axis and an outer thread, and a nut member cooperating with the spindle, wherein said spindle and nut member are mounted in said housing so as to be rotatable relative to one another, wherein the nut has a first bore and a second bore which intersect and form an angle with each other, wherein said first bore has an inner thread matching the outer thread of the spindle such that rotation of the spindle relative to the nut member causes the axial position of the nut member relative to the spindle to change, the position of the nut member on the spindle defining how far the piston rod is advanced during the injection, wherein said second bore is smooth and fits slidingly about the outer thread of said spindle, wherein the nut member is tiltable between a first position in which the first bore is coaxial with the spindle, and a second position, in which the second bore is coaxial with the spindle, such that said nut member can be moved into its first position during dose setting and injection operations and into its second position when it is desired to withdraw the piston rod and move said nut member along the spindle without rotating the spindle, and wherein the nut member is hinged to the piston rod at a first location such that exertion of a force by the nut member on the piston rod in a direction by which an injection is performed urges said nut member to tilt into its first position.

4. The syringe according to claim 3, wherein said syringe further comprises a piston withdrawal member which acts on the nut member at a second location such that the nut member is tilted to its second position when a piston rod withdrawal force is applied to said nut member.

5. The syringe according to claim 4, wherein said first and second locations are diametrically opposed.