Syringe and piston rod with gasket engaging portion
AssigneeOwen Mumford Limited
InventorDamian Alexander Holland
Life of this patent
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Abstract
A plunger rod for use in a syringe barrel for driving a bung through the syringe barrel to expel a substance therefrom, the plunger rod including: a bung fixing configured to be received within a recess of a bung and including at least one laterally extending lug including a thread engagement surface configured to engage with a point on a track portion of a thread on a sidewall of the recess, wherein the lug is further configured to cross the thread on relative rotation between the plunger rod and the bung under a force applied by a user, such that the thread engagement surface of the lug engages the point of the track portion every full rotation of the syringe plunger relative to the bung.
Claims17
A plunger comprising a plunger rod for use in a syringe barrel for driving a bung through the syringe barrel to expel a substance therefrom, the plunger comprising:
- a bung including a recess for receiving a bung fixing, the bung including a thread on a sidewall of the recess, the thread including a track portion, and
- the plunger rod including a bung fixing configured to be received within the recess of the bung and comprising first and second laterally extending lugs on opposite sides of the bung fixing, each lug comprising a thread engagement surface angled rearwards from a lateral axis to allow linear motion of each lug through the thread on the bung and configured to engage with a corresponding point on the track portion of the thread of the bung which is on the sidewall of the recess,
- wherein each lug is further configured to cross the thread by overcoming the thread on relative rotation between the plunger rod and the bung under a force applied by a user, such that the thread engagement surface of each lug engages the corresponding point of the track portion every full rotation of the plunger rod relative to the bung.
A plunger rod for use in a syringe barrel for driving a bung through the syringe barrel to expel a substance therefrom, the plunger rod comprising:
- a bung fixing configured to be received within a recess of the bung and comprising first and second laterally extending lugs on opposite sides of the bung fixing, each lug comprising a thread engagement surface angled rearwards from a lateral axis to allow linear motion of each lug through a thread on the bung and configured to engage with a corresponding point on a track portion of the thread of the bung which is on a sidewall of the recess,
- wherein each lug is further configured to cross the thread by overcoming the thread on relative rotation between the plunger rod and the bung under a force applied by a user, such that the thread engagement surface of each lug engages the corresponding point of the track portion every full rotation of the plunger rod relative to the bung,
- wherein a keyed portion of the plunger rod has a non-circular cross section configured to engage a corresponding keyed aperture of a syringe to prevent rotation of the plunger rod, and
- wherein each lug is positioned such that the thread engagement surface engages the point of the track portion of the thread when the cross section of the plunger rod is aligned with the keyed aperture.
Dependencies are inferred from the claim text.