US 5,735,825 A · Syringe plunger tip

Abstract

A sealing cap is provided for attachment to the end of a syringe plunger. The sealing cap has an annular sidewall with an annular first sealing wing projecting distally therefrom, an annular second sealing wing positioned proximal of the first sealing wing and projecting proximally, and an annular sealing ridge encircling and radially projecting out from between the first sealing wing and the second sealing wing. The sealing cap further includes an interior cavity having an annular side surface aligned with the annular sidewall. A side groove is recessed within the side surface so as to be aligned slightly proximal of the annular sealing ridge. The distal end of a syringe plunger has a head mounted thereon that is substantially complementary to the configuration of the internal cavity of the sealing cap. More specifically, a tapered ridge is formed on the periphery of the head to complementarily be received within the side groove. As a positive pressure is created against the sealing cap, the first sealing wing flexes against the interior surface of the barrel and the annular sealing ridge urges against the interior surface of the barrel, thereby increasing the effective seal. As a negative pressure is formed within the barrel, the second sealing wing flexes against the interior surface of the barrel to increase the effective seal.

Claims49

Dependent claims

A syringe plunger tip adapted to provide enhanced sealing engagement between the plunger tip and the interior surface of a syringe barrel at high pressures, the plunger tip comprising:

cap means for effecting sealing engagement with the interior surface of said syringe barrel so as to provide enhanced sealing at high pressures to prevent fluid leakage around the cap means;
head means for receiving said cap means in mating engagement, said head means and said cap means providing in combination the plunger tip;
wherein said cap means comprises variable sealing means formed at said radial periphery of said cap means so as to provide a sealing contact with the interior of the syringe barrel that increases with increasing pressure exerted against said plunger tip;
and
wherein said head means comprises engagement means positioned in said cap means for radially directing the pressure exerted on said cap means as the pressure increases so as to urge the variable sealing means into tighter engagement with the interior surface of the syringe barrel.

2 more elements

A sealing cap for attachment to the head of a syringe plunger to enable a sealing engagement between the sealing cap and the interior surface of a syringe barrel, the head of the plunger radially sloping outward to an annular outer edge, the sealing cap comprising:

(a) an annular sidewall having an exterior surface extending between a proximal end and a distal end;
(b) a crown mounted to the sidewall so as to cover the distal end of the sealing cap;
(c) an annular first sealing wing encircling and radially projecting outward in a distal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the first sealing wing contacting the interior surface of the barrel when the sealing cap attached to the head of the plunger is received within the barrel;
(d) an interior surface defining a cavity within the sealing cap, the interior surface being configured to complementary receive the head of the plunger, the cavity including an annular side face adjacent to and substantially parallel to the exterior surface of the sidewall, the interior surface further including an annular tapered groove recessed within the annular face, the groove being positioned relative to the sidewall so that a portion of the sidewall proximal of the first sealing wing is urged against the interior surface of barrel as pressure is increased within the barrel distal of the sealing cap;
and
(e) an end face positioned at the proximal end of the sidewall and defining an opening to the cavity through which the head of the plunger is received within the cavity of the sealing cap.

3 more elements

(a) an annular sidewall having an exterior surface extending between a proximal end and a distal end;
(b) a conical crown mounted on the annular sidewall so as to cover the distal end of the sealing cap;
(c) an annular first sealing wing encircling and radially projecting outward in a distal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the first sealing wing contacting the interior surface of the barrel when the sealing cap attached to the head of the plunger is received within the barrel;
(d) an annular second sealing wing encircling and radially projecting outward in a proximal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the second sealing wing being positioned proximal of the first sealing wing and contacting the interior surface of the barrel when the sealing cap attached to the head of the plunger is received within the barrel;
(e) an annular sealing ridge encircling and radially projecting out from the exterior surface of the sidewall between the fist sealing wing and the second sealing wing;
(f) an interior surface defining a cavity within the sealing cap, the cavity being configured to complementary receive the head of the plunger, the cavity including an annular side groove configured to complementary receive the outer edge of the head of the plunger, the side groove being positioned relative to the annular sealing ridge so that the annular, sealing ridge radially urges out to increasingly engage the interior surface of the barrel as the plunger is advanced within the barrel to increase the pressure within the barrel;
and
(g) an end face positioned at the proximal end of the sealing cap and defining an opening to the cavity through which the head of the plunger is received within the cavity of the sealing cap.

5 more elements

A syringe having an improved plunger tip adapted to provide enhanced sealing engagement between the plunger tip and an interior surface of a syringe barrel over a range of pressures characterized by (i) low pressures requiring low friction so as to enhance sensitivity to pressure changes exerted on the syringe plunger and so as to reduce friction of the syringe plunger at low pressures, and characterized by (ii) high pressures requiring enhanced sealing to prevent fluid leakage around the sealing cap, the syringe comprising:

(a) a barrel having an interior surface defining a lumen longitudinally extending through the barrel;
(b) an elongated plunger slidably received within the lumen of the barrel;
and
(c) a plunger tip comprising in combination a head positioned at one end of said plunger and a flexible sealing cap mounted on the head of the plunger, the sealing cap having a radial periphery that engages the interior surface of the barrel, and said sealing cap comprising:
i. primary sealing means formed on the sealing cap at said radial periphery thereof so as to provide a low friction sealing contact with the interior surface of the syringe barrel at low pressures of the pressure range;
and
ii. variable sealing means formed at said radial periphery of said sealing cap so as to provide a second sealing contact with the interior of the syringe barrel that increases with increasing pressure exerted against said plunger tip,
wherein said head comprises engagement means positioned in said sealing cap for radially directing the pressure exerted on said sealing cap as the pressure increases so as to urge the variable sealing means into tighter engagement with the interior surface of the syringe barrel.

5 more elements

A syringe for dispensing a fluid, the syringe comprising:

(a) a barrel having an interior surface defining a lumen longitudinally extending through the barrel;
(b) an elongated plunger having a distal end slidably receivable within the lumen of the barrel, the plunger further comprising a conical head positioned at the distal end of the plunger, the conical head radially sloping outward to an annular outer edge;
(c) a flexible sealing cap mounted on the head of the plunger, the sealing cap comprising:
(i) an annular sidewall having an exterior surface extending between a proximal end and a distal end;
(ii) a crown mounted on the annular sidewall so as to cover the distal end of the sealing cap;
(iii) an annular sealing ridge encircling and radially projecting out from the sidewall;
(iv) an interior surface defining a cavity within the sealing cap, the cavity having an annular side groove configured to complementary receive the outer edge of the head of the plunger, the side groove being positioned relative to the annular sealing ridge so that the annular sealing ridge radially urges out to increasingly engage the interior surface of the barrel as the plunger is advanced within the barrel to increase the pressure within the barrel;
and
(v) a end face positioned at the proximal end of the sealing cap and defining an opening to the cavity through which the head of the plunger is received within the cavity of the sealing cap.

6 more elements

A syringe for dispensing a fluid, the syringe comprising:

(a) a barrel having an interior surface defining a lumen longitudinally extending through the barrel;
(b) an elongated plunger having a distal end slidably received within the lumen of the barrel, the plunger further comprising a conical head positioned at the distal end of the plunger, the conical head radially sloping outward to a sharp annular outer edge;
(c) a flexible sealing cap mounted on the head of the plunger, the sealing cap comprising:
(i) an annular sidewall having an exterior surface extending between a proximal end and a distal end;
(ii) a conical crown mounted on the annular sidewall so as to cover the distal end of the sealing cap;
(iii) an annular first sealing wing encircling and radially projecting outward in a distal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the first sealing wing contacting the interior surface of the barrel when the distal end of the plunger is received within the barrel;
(iv) an annular second sealing wing encircling and radially projecting outward in a proximal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the second sealing wing being positioned proximal of the first sealing wing and contacting the interior surface of the barrel when the sealing cap attached to the head of the plunger is received within the barrel;
(v) an annular sealing ridge encircling and radially projecting out from the exterior surface of the sidewall between the fist sealing wing and the second sealing wing;
(vi) an interior surface defining a cavity within the sealing cap, the cavity being configured to complementary receive the head of the plunger, the cavity including an annular side groove configured to complementary receive the outer edge of the head of the plunger, the side groove being positioned relative to the annular sealing ridge so that the annular sealing ridge radially urges out to increasingly engage the interior surface of the barrel as the plunger is advanced within the barrel to increase the pressure within the barrel;
and
(vii) a annular end face positioned at the proximal end of the sealing cap and defining an opening to the cavity through which the head of the plunger is received within the cavity of the sealing cap.

8 more elements

A method for dispensing a fluid through a syringe, the method comprising the steps of:

(a) obtaining a syringe comprising:
(i) a barrel having an interior surface defining a lumen longitudinally extending between an access end and a discharge end;
(ii) an elongated plunger having a distal end slidably received within the access end of the barrel, the plunger further comprising a conical head positioned at the distal end of the plunger, the conical head radially sloping outward to an annular outer edge;
(iii) a flexible sealing cap mounted on the head of the plunger, the sealing cap comprising:
(A) an annular sidewall having an exterior surface extending between a proximal end and a distal end;
(B) a conical crown mounted on the annular sidewall so as to cover the distal end of the sealing cap;
(C) an annular first sealing wing encircling and radially projecting outward in a distal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the first sealing wing contacting the interior surface of the barrel when the distal end of the plunger is received within the barrel;
(D) an annular second sealing wing encircling and radially projecting outward in a proximal direction from the exterior surface of the sidewall at an angle less than 90.degree. relative to the longitudinal axis of the sealing cap, the second sealing wing being positioned proximal of the first sealing wing and contacting the interior surface of the barrel when the sealing cap attached to the head of the plunger is received within the barrel;
(E) an annular sealing ridge encircling and radially projecting out from the exterior surface of the sidewall between the fist sealing wing and the second sealing wing;
(F) an interior surface defining a cavity within the sealing cap, the cavity being configured to complementary receive the head of the plunger, the cavity including an annular side groove configured to complementary receive the outer edge of the head of the plunger, the side groove being positioned relative to the annular sealing ridge so that the annular sealing ridge radially urges out to increasingly engage the interior surface of the barrel as the plunger is advanced within the barrel to increase the pressure within the barrel;
and
(G) an end face positioned at the proximal end of the sealing cap and defining an opening to the cavity through which the head of the plunger is received within the cavity of the sealing cap;
(b) attaching the discharge end of the barrel in fluid communication with to a fluid source;
(c) retracting the plunger from within the barrel so that the second sealing wing urges against the interior surface of the barrel so as to produce a seal that causes the fluid to flow into the barrel;
and
(d) advancing the plunger within the barrel so that the first sealing wing and the sealing ridge urge against the interior surface of the barrel to produce a seal that causes the fluid to discharge from the barrel though the discharge end.

13 more elements

Dependencies are inferred from the claim text.

Syringe plunger tip

Life of this patent

Syringe plunger tip

Life of this patent

Abstract

Claims49