초록 ▼

A dose metering device for use with a syringe comprises a fixed screwthreaded member (17) which is either integral with or fixed in use to the cylinder (10) of the syringe and is in threaded engagement with a screwthreaded plunger (13) which can be rotated by a manually-rotatable cap (30) acting thr

A dose metering device for use with a syringe comprises a fixed screwthreaded member (17) which is either integral with or fixed in use to the cylinder (10) of the syringe and is in threaded engagement with a screwthreaded plunger (13) which can be rotated by a manually-rotatable cap (30) acting through a ratchet and pawl mechanism (32, 34) whose ratchet wheel (26) drives a driving rod (24) which is slidably keyed to the plunger (13). The plunger engages the piston or plug (11) of the syringe. A stop (42) limits rotation of the cap (30) which can be turned away from the stop through a variable angle to a selected angular position shown on a scale (39) of volumetric dose units, the pawl (32) overriding the ratchet teeth (34), to preset a dose to be expressed. The cap (30) can then be turned back to the stop, rotating the plunger (13) via the ratchet and pawl mechanism and causing the plunger to advance the syringe piston or plug (11) through a corresponding axial distance so as to express a metered dose, corresponding to the setting preset on the scale, from the syringe. A succession of preset doses, of the same or different volumes can thus be expressed from the syringe until it is empty. The syringe may employ a prefilled ampoule (50B) of dose liquid which is sealed by a sliding plug (11B) engaged in use by the screw plunger (13B).

대표청구항 ▼

A dose metering device for a syringe having a cylinder in which a piston moves to express liquid therefrom, which device comprises an axially-movable plunger which is adapted in use to drive the piston axially in the cylinder for dose expression therefrom, a manually-rotatable operating member, a ro

A dose metering device for a syringe having a cylinder in which a piston moves to express liquid therefrom, which device comprises an axially-movable plunger which is adapted in use to drive the piston axially in the cylinder for dose expression therefrom, a manually-rotatable operating member, a rotary screw mechanism operatively associated with the plunger, a unidirectional coupling by which the operating member is operatively coupled to the rotary screw mechanism, angular rotation of the operating member in one direction (referred to as the forward direction) being transmitted by the unidirectional coupling to the rotary screw mechanism which is arranged to convert said transmitted rotation into corresponding axial movement of the plunger, whereby in use successive rotary operating strokes of the operating member in the said forward direction are converted into successive axial movement steps of the plunger to express successive doses from the syringe whose volumes correspond to the angular extents of the respective operating strokes of the operating member, and stop means arranged to limit each of the said operating strokes of the operating member at the same predetermined angular finishing point, the unidirectional coupling permitting the manual angular retraction of the operating member independently of the plunger after each said operating stroke from its finishing point predetermined by the stop means to a selected angular position constituting a variable starting point for the next operating stroke, and scale means arranged to indicate selectable angular positions of a plurality of said starting points, whereby the volume of each dose to be expressed is variably preset in use by selection of the angular position, as indicated by the scale means, of the starting point of the respective operating stroke of the operating member.