Injection syringe
US6004297A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1999 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | Jan 28, 2019 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61M5/31575
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An injection syringe comprises a housing (1), a piston rod (6) with a non-circular cross-section and an outer thread (7), a piston rod drive which includes a piston rod guide (85) mating with the cross-section of the piston rod (6), and a nut (4) which is not axially displaceable and which mates with the thread (7) of the piston rod (6) to form a self-locking thread connection. Rotation of a dose setting element (81) causes an injection button to be screwed out to project from the housing (1). When the injection button (88) is pushed axially, such axial movement is transformed, by way of the threaded coupling, into a rotation of one of the piston drive elements (85) relative to the other one (4). A unidirectional coupling between the nut member (4) and the piston rod guide (85) allows rotation in one direction by which the piston rod (6) is transported in a distal direction. The coupling has an initial reluctance to be overcome before rotation takes place, said reluctance being large enough to resist torques exerted during the dose setting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.