Drive mechanism for an injection device
First Claim
1. A drive mechanism for an injection device in which piston means are selectively driven to expel medicament from within a medicament cartridge, the drive mechanism comprising:
- a drive means;
a first gear means associated with the drive means;
a second gear means moveable between a first position in which only movement along a longitudinal axis of the second gear means is permitted and a second position in which the second gear means is free to rotate about the longitudinal axis;
a piston means associated with the second gear means;
a housing within which the first gear means and the second gear means are constrained for movement; and
a biasing means located between the housing and the second gear means to bias the second gear means to the first position.
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Accused Products
Abstract
A drive mechanism for an injection device is disclosed in which piston means are selectively driven to expel medicament from within a medicament cartridge. The drive mechanism comprises a drive means (270), first means (278) associated with the drive means, second gear means (274) being moveable between a first position in wich only movement along its longitudinal axis is permitted and a second position in which the second gear means (274) is free to rotate about the longitudinal axis, the piston means (280) being associated with the second gear means (274), a housing (276) within which the first gear means (278) and the second gear means (274) are constrained for movement, and biassing means (282) located between the housing (276) and a second gear means (274) to bias the second gear means (274) to the first position.
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Citations
16 Claims
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1. A drive mechanism for an injection device in which piston means are selectively driven to expel medicament from within a medicament cartridge, the drive mechanism comprising:
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a drive means; a first gear means associated with the drive means; a second gear means moveable between a first position in which only movement along a longitudinal axis of the second gear means is permitted and a second position in which the second gear means is free to rotate about the longitudinal axis; a piston means associated with the second gear means; a housing within which the first gear means and the second gear means are constrained for movement; and a biasing means located between the housing and the second gear means to bias the second gear means to the first position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification