CPC A61M 5/3155 (2013.01) [A61M 5/2422 (2013.01); A61M 5/31528 (2013.01); A61M 5/31533 (2013.01); A61M 5/31551 (2013.01); A61M 5/31583 (2013.01); A61M 5/31593 (2013.01); A61M 5/24 (2013.01); A61M 5/3156 (2013.01); A61M 5/31501 (2013.01); A61M 5/31511 (2013.01); A61M 5/31526 (2013.01); A61M 5/31541 (2013.01); A61M 5/31585 (2013.01); A61M 2205/581 (2013.01); A61M 2205/582 (2013.01)] | 13 Claims |
1. A pen-type injector comprising:
a housing;
a piston rod having a screw thread;
an insert located in the housing, the piston rod and the insert being configured to allow the piston rod to rotate through the insert;
a dose dial sleeve rotatable with respect to the housing and the insert; and
a drive sleeve which is axially displaceable with respect to the housing,
wherein a maximum angular displacement of the dose dial sleeve with respect to the housing is determined by abutment of a radially directed lug on the dose dial sleeve with a catch on the insert,
wherein the drive sleeve comprises (i) a first part having a first diameter located between the insert and the piston rod and (ii) a second part having a second diameter located between the piston rod and the dose dial sleeve, and
wherein an internal surface of the drive sleeve is splined to the piston rod to prevent relative rotation between the drive sleeve and the piston rod and allow relative longitudinal displacement between the drive sleeve and the piston rod.
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