Dose mechanism for an injection device for limiting a dose setting corresponding to the amount of medicament left
DCFirst Claim
1. A mechanism for preventing setting of a dose which exceeds the amount of a medicament in a reservoir in an injection device, wherein a dose is set by rotating a dose setting member of a dose setting mechanism, the mechanism comprising:
- a piston rod having a threaded outer surface;
a housing defining a passage for the piston rod, the passage having a threaded inner surface for engagement with the threaded outer surface of the piston rod, the housing being arranged with respect to the piston rod such that rotation of the piston rod in relation to the housing causes the piston rod to be displaced relative to the housing in a longitudinal direction;
a limiter defining a passage for the piston rod;
a driver defining a passage for the limiter, the driver being coupled to the dose setting member such that rotation of the dose setting member during dose setting causes the driver to rotate; and
wherein the limiter is coupled to the driver and the piston rod such that relative rotation between the driver and the piston rod during dose setting causes the limiter to move towards a stopping position wherein the limiter prevents setting of a dose which exceeds the amount of a medicament in a reservoir in the injection device.
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Abstract
A mechanism for preventing setting of a dose, which exceeds the amount of a medicament in a reservoir in an injection device. The device can contain a threaded piston rod, a limiter and a driver. The three elements can be arranged such that during dose setting, the limiter is moved towards an end-of-content position, wherein dose setting is limited. The invention contains an accumulative and a non-accumulative embodiment. The invention further relates to a mechanism for preventing ejection of a dose exceeding the set dose.
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Citations
25 Claims
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1. A mechanism for preventing setting of a dose which exceeds the amount of a medicament in a reservoir in an injection device, wherein a dose is set by rotating a dose setting member of a dose setting mechanism, the mechanism comprising:
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a piston rod having a threaded outer surface; a housing defining a passage for the piston rod, the passage having a threaded inner surface for engagement with the threaded outer surface of the piston rod, the housing being arranged with respect to the piston rod such that rotation of the piston rod in relation to the housing causes the piston rod to be displaced relative to the housing in a longitudinal direction; a limiter defining a passage for the piston rod; a driver defining a passage for the limiter, the driver being coupled to the dose setting member such that rotation of the dose setting member during dose setting causes the driver to rotate; and wherein the limiter is coupled to the driver and the piston rod such that relative rotation between the driver and the piston rod during dose setting causes the limiter to move towards a stopping position wherein the limiter prevents setting of a dose which exceeds the amount of a medicament in a reservoir in the injection device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification