PEN-TYPE DRUG INJECTION DEVICE WITH DOSE SETTING AND RE-SETTING MECHANISM

• US 20160206826A1
• Filed: 09/03/2014
• Published: 07/21/2016
• Est. Priority Date: 09/03/2013
• Status: Active Grant

• Current Assignee: Sanofi
• Original Assignee: Sanofi
• Inventors: Bilton, Simon Lewis, Plumptre, David Aubrey, Jones, Matthew, Butler, Joseph
• Granted Patent: US 10,286,155 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/202 cocking means, e.g. to bias the main drive spring of an injector
• CPC Class Codes: A61M 2005/2073 preventing premature release, e.g. by making use of a safety lock
• CPC Class Codes: A61M 2005/3126 Specific display means related to dosing
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/31528 by means of rotational movements, e.g. screw-thread mechanisms
• 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 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• 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 5/31583 based on rotational translation, i.e. movement of piston rod is caused by relative rotation between the user activated actuator and the piston rod
• CPC Class Codes: A61M 5/31586 performed by rotationally moving or pivoted actuator, e.g. an injection lever or handle
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

The present invention relates to a pen type drug injection device (1; 101) comprising a housing (4, 5; 104, 105), a dose dial member (6; 106), a torsion spring (12; 112) fixed between the housing and the dial member such that energy is accumulated in the torsion spring upon rotation of the dial member relative to the housing, a drive member (8; 108) engaging a lead screw (9; 109), a first clutch (18; 118) rotationally coupling the drive member (8; 108) and the housing in a coupled state and allowing relative rotation between the drive member and the housing in a de-coupled state, and a second clutch (19; 119) rotationally coupling the drive member and the dial member in a coupled state and allowing relative clockwise and anti-clockwise rotation between the drive member and the dial member in a de-coupled state. The second clutch comprises a ratchet clicker with teeth (19a, 19b; 119a, 119b) having in the clockwise and the anti-clockwise direction different ramped tooth angles such that the teeth are allowed to override each other in the de-coupled state of the second clutch with a different resistance in the clockwise and the anti-clockwise direction, such that a dose can be set and also corrected by the user thereby tensioning respectively relaxing the torsion spring.

Claims

1. Drive mechanism for an injection device, the mechanism comprising:

a housing (4, 5;

104, 105),

a dial member (6;

106),

a torsion spring (12;

112) fixed between the housing (4, 5;

104, 105) and the dial member (6;

106) such that energy is accumulated in the torsion spring (12;

112) upon rotation of the dial member (6;

106) relative to the housing (4, 5;

104, 105),

a drive member (8;

108) engaging a lead screw (9;

109),

a first clutch (18;

118) rotationally coupling the drive member (8;

108) and the housing (4, 5;

104, 105) in a coupled state and allowing relative rotation between the drive member (8;

108) and the housing (4, 5;

104, 105) in a de-coupled state,

a second clutch (19;

119) rotationally coupling the drive member (8;

108) and the dial member (6;

106) in a coupled state and allowing relative clockwise and anti-clockwise rotation between the drive member (8;

108) and the dial member (6;

106) in a de-coupled state,

wherein the second clutch (19;

119) comprises a ratchet clicker with teeth (19a, 19b;

119a, 119b) having in the clockwise and the anti-clockwise direction different ramped tooth angles such that the teeth (19a, 19b;

119a, 119b) are allowed to override each other in the de-coupled state of the second clutch (19;

119) with a different resistance in the clockwise and the anti-clockwise direction.

2. Drive mechanism according to claim 1, wherein the teeth (19a, 19b;

119a, 119b) have a steeper ramped tooth angle in the rotational direction in which the torsion spring biases the dial member (6;

106) and have a shallower ramped tooth angle in the opposite rotational direction.

3. Drive mechanism according to claim 1 or 2, wherein the teeth (19a, 19b;

119a, 119b) have a higher friction coefficient in the rotational direction in which the torsion spring biases the dial member (6;

106) and have a lower friction coefficient in the opposite rotational direction.

4. Drive mechanism according to any of claims 1 to 3, wherein during dose setting and dose resetting the first clutch (18;

118) is in its coupled state and the second clutch (19;

119) is in its de-coupled state.

5. Drive mechanism according to any of claims 1 to 4, wherein during dose setting and dose resetting the torsion spring (12;

112) and/or an additional spring (13;

121) biases the first clutch (18;

118) in its coupled state and/or pulls the second clutch (19;

119) in its de-coupled state.

6. Drive mechanism according to any of claims 1 to 5, wherein during dose setting and dose resetting the teeth (19a, 19b;

119a, 119b) of the second clutch (19;

119) engage in the de-coupled state but are allowed to override each other by an axial movement against the force of an elastic member.

7. Drive mechanism according to any of claims 1 to 6, wherein during dose dispensing the first clutch (18;

118) is in its de-coupled state and the second clutch (19;

119) is in its coupled state.

8. Drive mechanism according to any of claims 1 to 7, wherein the first clutch (18;

118) is coupled and de-coupled by axially displacing the drive member (8;

108) relative to the housing (4, 5;

104, 105).

9. Drive mechanism according to any of claims 1 to 7 further comprising a trigger clutch (122) which is held rotationally fixed and axially displaceable within the housing (4, 5;

104, 105), wherein the first clutch (18;

118) is de-coupled by axially displacing the trigger clutch (122) relative to the drive member (8;

108).

10. Drive mechanism according to claim 9 further comprising a trigger (123) pivotably attached to the housing (4, 5;

104, 105), wherein the trigger (123) engages the trigger clutch (122) such that swiveling of the trigger (123) relative to the housing (4, 5;

104, 105) axially displaces the trigger clutch (122).

11. Drive mechanism according to any of claims 1 to 10, wherein the first clutch (18;

118) comprises splines (18b;

118b) on an outer surface of the drive member (8;

108) and corresponding notches (18a;

118a) on an inner surface of the housing (4, 5;

104, 105) or on an inner surface of a housing insert (122).

12. Drive mechanism according to any of claims 1 to 11, wherein the second clutch (19;

119) comprises face teeth (19b;

119b) on a front edge of the drive member (8;

108) and corresponding face teeth (19a;

119a) on a front edge of the dial member (6;

106) or on a front edge of a clutch plate (16).

13. Drive mechanism according to any of claims 1 to 12 further comprising a clutch plate (16) rotationally fixed to the dial member (6;

106), wherein the second clutch (19;

119) is coupled and de-coupled by axially displacing the clutch plate (16) relative to the drive member (8;

108).

14. Drive mechanism according to any of claims 1 to 13 further comprising a display member (7;

107) in threaded engagement with the housing (4, 5;

104, 105), wherein the display member (7;

107) is rotationally fixed to the dial member (6;

106) and displaceable relative to the dial member (6;

106) in an axial direction.

15. Drive mechanism according to any of claims 1 to 14 further comprising a nut (11;

111) which is guided axially displaceable and non-rotatable on the drive member (8;

108) and which has an external thread engaging an internal thread of the dial member (6;

106) such that relative rotation between the drive member (8;

108) and the dial member (6;

106) during dose setting causes the nut (11;

111) to move towards an end stop, wherein the nut (11;

111) preferably prevents setting of a dose exceeding the amount of a medicament in the injection device.

16. Drive mechanism according to any of claims 1 to 15, the housing (4, 5;

104, 105) further comprising helical stop features (125) cooperating with the drive member (8;

108), wherein the drive member (8;

108) and the lead screw (9;

109) are in threaded engagement.