Dripless automatic syringe for dispensing fluids
US4923096A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 9, 1989 |
| Grant date | May 8, 1990 |
| Priority date | — |
| Expiry date | Jan 9, 2009 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05C17/014
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
This dripless automatic syringe for dispensing fluids has a barrel for containing the fluid, a nozzle for discharging the fluid, and a housing to which the barrel is attached. A piston rod in the housing carries a rigid sealed piston head in the barrel for pushing out the fluid. Behind the piston head a normally unflexed elastic disc in the housing. The disc flexes when the piston rod moves forwardly under a driving force. The disc unflexes to retract the piston rod and piston head slightly when the driving force stops to create a suction which draws fluid back into the nozzle and thereby prevents dripping. The disc has an integral nipple which frictionally grips the rod to hold it in place, when the driving force ceases. The nipple permits axial rearward movement of the piston rod by an externally applied force for filling the barrel with fluid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.