PROTECTIVE DEVICE

The present invention provides an anti-backup device which prevents the nut (10) from moving up the threaded piston (5) at the end of the dose by rotating in the opposite direction of that in which the nut (10) moves up the position to set the new dose by rotating dose knob. In this way, it is assur...

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Bibliographic Details
Main Author HARRIS DALE C
Format Patent
LanguageEnglish
Published 31.12.1997
Edition6
Subjects
DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY
DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROMTHE BODY
HUMAN NECESSITIES
HYGIENE
MEDICAL OR VETERINARY SCIENCE
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Summary:The present invention provides an anti-backup device which prevents the nut (10) from moving up the threaded piston (5) at the end of the dose by rotating in the opposite direction of that in which the nut (10) moves up the position to set the new dose by rotating dose knob. In this way, it is assured that movement of the nut up the threaded piston is due to rotating the dose knob (15) in the proper direction. The preferred device is a pawl (25) mounted on the end of a flexible arm (32) of the nut which cooperates with slots (26) on the inside of the syringe barrel (27). The nut (10) also has an incline surface (28) at the end which mates with an incline surface (29) in the barrel (27) and the mating of these surfaces at the end of the dose forces the pawl (25) into a slot (26) and prevents rotation of the nut (10) in the wrong direction, thus preventing refilling of the syringe.
Bibliography:Application Number: PL19930300751