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US 7,740,618 B2Granted
Syringe device
AssigneeNovo Nordisk A/S
InventorTom Hede Markussen
Life of this patent
Estimating the term…
Abstract
A ratchet-free and gear-free one-to-one mechanism for setting a dose in a syringe device comprising a dose setting member adapted to be rotated along a piston rod with a threaded outer surface so as to set a dose to be ejected. During dose setting the piston rod is locked such that rotational movement of the dose setting member does not result in rotational movement of the piston rod. During dose ejection the piston rod and the dose setting member are locked in relation to each other such that translational movement of the dose setting member causes relative rotational and translational movement of the piston rod.
Claims22
A syringe device comprising:
- a housing;
- a first member (112, 212) that is axially fixed to the housing;
- a piston rod (106;206) having a threaded outer surface, the piston rod (106;206) being retained in relation to the first member(112;212) in such a way that no relative rotation of the piston rod (106;206) and the first member (112;212) is possible and in such a way that the piston rod (106;206) can slide longitudinally relative to the first member (112;212);
- a dose setting member (108;208) defining a passage for the piston rod (106;206), the passage having a threaded inner surface for engagement with the threaded outer surface of the piston rod (106;206), so as to define a connection between the dose setting member (108;208) and the piston rod (106;206), the dose setting member (108;208) being arranged with respect to the piston rod (106;206) such that rotation of the dose setting member (108;208) causes the dose setting member (108;208) to be displaced longitudinally along the piston rod (106;206), whereby a stroke length of the piston rod (106;206) is defined by the longitudinal displacement of the dose setting member (108;208) in a proximal direction (104) relative to a predetermined position of the dose setting member (108;208), and such that a translational displacement of the dose setting member (108;208) relative to the housing is transmittable via said connection into a translational displacement of the piston rod (106;206) relative to the housing;
- a second member (110;210) defining a passage for the piston rod (106;206) the passage having a threaded inner surface for engagement with the threaded outer surface of the piston rod (106;206), and;
- a first locking means (126;250) for locking the first member (112;212) and second member (110;210) against relative rotation, so that no displacement of the piston rod (106;206) in the proximal direction (104) is possible, when the first locking means (126;250) is in its locking position,
- characterized by
- a spring (118;218) which interconnects the second member (110;210) and the dose setting member (108;208) and biases them towards each other, such that when the dose setting member (108;208) is rotated and thereby displaced longitudinally along the piston rod (106;206), the spring is strained, and such that translational displacement of the dose setting member (108;208) and the piston rod (106;206) in the distal direction (102) to eject the dose unstrains the spring (118;218), whereby energy accumulated during straining of the spring (118;218) is released to provide said ejection force.
5 more elements
A syringe device comprising:
- a housing;
- a first member that is axially fixed to the housing;
- a piston rod (106) having a threaded outer surface, the piston rod (106) being retained in relation to the first member (112) in such a way that no relative rotation of the piston rod (106) and the first member (112) is possible and in such a way that the piston rod (106) can slide longitudinally relative to the first member (112);
- a dose setting member (108) defining a passage for the piston rod (106), the passage having a threaded inner surface for engagement with the threaded outer surface of the piston rod (106), so as to define a connection between the dose setting member (108) and the piston rod (106), the dose setting member (108) being arranged with respect to the piston rod (106) such that rotation of the dose setting member (108) causes the dose setting member (108) to be displaced longitudinally along the piston rod (106), whereby a stroke length of the piston rod (106) is defined by the longitudinal displacement of the dose setting member (108) in a proximal direction (104) relative to a predetermined position of the dose setting member (108), and such that a pure translational displacement of the dose setting member (108) relative to the housing is transmittable via said connection into a pure translational displacement of the piston rod (106) relative to the housing, and;
- a second member (110) defining a passage for the piston rod (106), the passage having a threaded inner surface for engagement with the threaded outer surface of the piston rod (106),
- characterized by
- at least one end surface of the second member (110) being arranged to abut a stop surface (114) of the first member (112), so that the piston rod (106) is locked against displacement in the proximal direction (104) when the surface of the second member (110) abuts the stop surface (114) of the first member (112).
4 more elements
Dependencies are inferred from the claim text.