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A disposable syringe has a needle seat with an upper segment adapted
to be sleeved over by a needle unit, and a lower segment retained
in a passage of a barrel. A plunger has a stem portion movable in
the passage, a surrounding engaging portion in sealing contact with
the passage so as to be moved by the stem portion of the plunger
in a position of use, and a head which is moved towards and is held
by a grip segment in the needle seat when the surrounding engaging
portion is depressed by an edge portion of the needle seat by virtue
of a continuing depression force of the plunger, thereby permitting
the needle seat to be brought into the passage for safe disposal.
A disposable syringe device auxiliary unit of the present invention
for preventing iatrogenic infection through a needle includes a
cap holding section for disposing and holding therein a cap which
covers, when a medical treatment is performed, a needle positioned
at the extreme end of a syringe barrel constituting a disposable
syringe device; and a needle separating section for separating the
needle, which is covered with the cap and fitted on an end of the
syringe barrel, therefrom.
A disposable syringe includes a tubular barrier member retained
in a rear passageway of a barrel. A tubular needle seat for fixing
a needle cannula is retained on the barrier member, and abuts against
an abutment wall in the front passageway of the barrel while the
needle cannula is disposed outwardly of the barrel. A plunger is
slidable in the rear passageway, and has a seal member to seal a
cavity confined in a plunger body and containing a fluid at a reduced
pressure. When a pushing force applied to the plunger body moves
the barrier member against the first and second frictional forces,
the needle seat is released, and the seal member is ruptured, so
that the needle seat and the needle cannula are suctioned into the
cavity due to the pressure difference between the ambient atmosphere
and the reduced pressure.
A disposable syringe comprises a syringe body (1), a plunger (40)
mounted on a stem (50) slidable inside the syringe body (1), and
an injection needle (10) integral with a needle-carrier (11) engageable
with the fore end (2) of the syringe body (1) or the plunger, retaining
means (20 23 24) able to retain spring means (30) under compression
being provided integrally with the syringe body (1) and engagement
means (59) able to cooperate with the retaining means (23) to release
the spring means (30), when the plunger (40) has reached the end
of its stroke, being provided integrally with said stem (50), so
that the spring means (30) can act on the stem (50) to cause retraction
thereof into the retracted position.
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