U.S. patent application number 13/873871 was filed with the patent office on 2014-09-18 for liquid dispensing syringe.
This patent application is currently assigned to Nordson Corporation. The applicant listed for this patent is NORDSON CORPORATION. Invention is credited to Mohammad Ali, Scott Conner.
Application Number | 20140263403 13/873871 |
Document ID | / |
Family ID | 50277014 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140263403 |
Kind Code |
A1 |
Conner; Scott ; et
al. |
September 18, 2014 |
Liquid Dispensing Syringe
Abstract
A syringe for dispensing liquid materials to a substrate. In one
embodiment, the syringe includes a barrel having a first end, a
second end, and an interior reservoir. A piston is slidably
disposed within the reservoir and is movable to increase or
decrease a volume of the interior reservoir near the first end of
the barrel. At least a portion of at least one of the barrel, the
piston, or the dispensing tip comprises a material selected to
maintain operative structural integrity of the dispensing syringe
at elevated temperatures.
Inventors: |
Conner; Scott; (Foxboro,
MA) ; Ali; Mohammad; (Holland, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NORDSON CORPORATION |
Westlake |
OH |
US |
|
|
Assignee: |
Nordson Corporation
Westlake
OH
|
Family ID: |
50277014 |
Appl. No.: |
13/873871 |
Filed: |
April 30, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61794551 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
222/1 ; 222/386;
222/389 |
Current CPC
Class: |
B05C 11/1034 20130101;
B65D 83/0005 20130101; B05C 5/0212 20130101; H05K 3/3485
20200801 |
Class at
Publication: |
222/1 ; 222/386;
222/389 |
International
Class: |
B65D 83/00 20060101
B65D083/00 |
Claims
1. A dispensing syringe, comprising: a barrel having a first end
and a second end, and defining an interior reservoir therein; a
dispensing tip proximate said first end of said barrel, said
dispensing tip including an outlet in fluid communication with said
reservoir; wherein at least a portion of at least one of said
barrel or said dispensing tip comprises a material selected to
maintain operative structural integrity of the dispensing syringe
at temperatures above about 150 degrees Celsius.
2. The dispensing syringe of claim 1, wherein said material
comprises a high temperature resin.
3. The dispensing syringe of claim 2, wherein said material
comprises polybutylene terephthalate.
4. The dispensing syringe of claim 2, wherein said material is a
composite material that further comprises fiber reinforcement.
5. The dispensing syringe of claim 1, further comprising: an
adapter selectively removably coupled to said second end of said
barrel for coupling said barrel to a source of pressurized
fluid.
6. The dispensing syringe of claim 1, further comprising: a piston
slidably disposed within said interior reservoir.
7. The dispensing syringe of claim 6, wherein the piston comprises
polybutylene terephthalate.
8. The dispensing syringe of claim 6 further comprising a hot melt
adhesive disposed in the interior reservoir.
9. A dispensing syringe, comprising: a barrel having a first end
and a second end, and defining an interior reservoir therein; a
piston slidably disposed within said reservoir to thereby increase
or decrease a volume of said interior reservoir proximate said
first end of said barrel; said piston having a first end and a
second end, said first end having a generally
hemispherically-shaped surface profile with an elongated apex
extending along a central axis thereof for dispensing fluid from
said first end of said barrel when said piston is moved toward said
first end of said barrel; and a luer coupling at said first end of
said barrel adapted for receiving a dispensing tip; said luer
coupling including an outlet orifice and an outlet passage in fluid
communication between said outlet orifice and said reservoir; said
outlet passage tapered along an axial length thereof; wherein at
least a portion of at least one of said barrel, said piston, or
said luer coupling comprises a material selected to maintain
operative structural integrity of the dispensing syringe at
temperatures above about 150 degrees Celsius.
10. The dispensing syringe of claim 9, wherein said material
comprises a high temperature resin.
11. The dispensing syringe of claim 10, wherein said material
comprises polybutylene terephthalate.
12. The dispensing syringe of claim 10, wherein said material is a
composite material that further comprises fiber reinforcement.
13. The dispensing syringe of claim 9, further comprising: an
adapter selectively removably coupled to said second end of said
barrel for coupling said barrel to a source of pressurized
fluid.
14. The dispensing syringe of claim 9, further comprising: an end
cap selectively removably coupled to said second end of said barrel
for sealing said barrel.
15. The dispensing syringe of claim 9, further comprising: a tip
cap selectively removably coupled to said luer coupling at said
first end of said barrel and sealingly engaging said outlet orifice
of said luer coupling when said tip cap is firmly seated on said
luer coupling.
16. The dispensing syringe of claim 9, wherein said barrel further
comprises: an elongate tubular body including at least one sidewall
defining said interior reservoir; said sidewall further defining a
hemispherically-shaped portion within said interior reservoir
proximate said first end of said body and complementary to said
hemispherically-shaped surface profile of said piston.
17. The dispensing syringe of claim 16, wherein said barrel further
comprises: a radially inwardly extending ledge within said interior
reservoir adjacent said hemispherically-shaped portion, said
sidewall having a substantially uniform thickness proximate said
ledge, whereby the location of said radially inwardly extending
ledge is visible externally of said body by a corresponding
radially outwardly extending ledge.
18. The dispensing syringe of claim 9, further comprising a hot
melt adhesive disposed in said interior reservoir.
19. A method of dispensing a hot melt adhesive, comprising: heating
a dispensing syringe to liquefy hot melt adhesive disposed within
an interior reservoir of the dispensing syringe, the dispensing
syringe comprising: a barrel having a first end and a second end
and defining the interior reservoir therein, a dispensing tip
proximate the first end of the barrel, an outlet in fluid
communication with the interior reservoir, and a piston slidably
disposed within the interior reservoir, wherein at least a portion
of at least one of the barrel or the dispensing tip comprises a
material selected to maintain operative structural integrity of the
dispensing syringe at temperatures above about 150 degrees Celsius;
and moving the piston in a direction toward the dispensing tip to
dispense the hot melt adhesive from the outlet.
20. The method of claim 19, wherein the dispensing syringe further
comprises: a luer coupling at the first end of the barrel and
adapted for receiving the dispensing tip, the luer coupling
including an outlet orifice and an outlet passage in fluid
communication between the outlet orifice and the reservoir, the
outlet passage tapered along an axial length thereof; wherein the
piston has a first end and a second end, the first end having a
generally hemispherically-shaped surface profile with an elongated
apex extending along a central axis thereof for dispensing fluid
from the first end of the barrel when the piston is moved toward
the first end of said barrel; and wherein at least a portion of at
least one of the barrel, the piston, or the luer coupling comprises
a material selected to maintain operative structural integrity of
the dispensing syringe at temperatures above about 150 degrees
Celsius.
Description
CROSS-REFERENCE
[0001] This application claims the filing benefit of U.S.
Provisional Patent Application Ser. No. 61/794,551 filed on Mar.
15, 2013, which is incorporated by reference herein in its
entirety.
TECHNICAL FIELD
[0002] This invention relates generally to the field of dispensing
liquid materials, and more particularly to a syringe for dispensing
liquid materials.
BACKGROUND
[0003] Various types of dispensers are used in many industries for
placing liquids, such as adhesives, conformal coating materials,
solder paste, solder flux, and other similar materials, onto
substrates during an assembly process. One type of liquid dispenser
is a syringe-type dispenser having a dispenser body defining a
barrel reservoir for holding a supply of liquid material to be
dispensed. A dispensing tip is coupled to the syringe at one end,
and is in fluid communication with the reservoir. A piston disposed
in the reservoir is movable therein to pressurize the liquid in the
reservoir and thereby dispense a small amount of liquid from the
dispensing tip and onto a substrate.
[0004] Many industrial applications require that the liquid be
dispensed in very precise volumes and at precise locations. To this
end, liquid dispensers include actuators for moving the piston
within the reservoir in a controllable and predictable manner. For
instance, pneumatic actuators are known in the art and use
compressed air applied to the piston to move the piston and
dispense liquid from the dispenser. Those skilled in the art will
recognize that other types of actuators, such as linear actuators,
may be used to control movement of the piston within the reservoir.
In other applications where precise dispensing is not required, the
piston may be moved through manual processes.
[0005] In some applications, the liquid to be dispensed must be
heated to about 150 degrees Celsius, or even higher. For example,
dispensing hot melt type adhesives, such as polyurethane adhesives
(PUR), typically require heating the adhesive to about 150 degrees
Celsius, or higher, and maintaining the adhesive at that
temperature until it is dispensed to a desired substrate. When
syringe-type dispensers used to dispense such liquids comprise
polymeric materials, the elevated temperatures may affect the
integrity or performance of the syringe components and limit the
effectiveness of the dispenser. A need exists for a syringe-type
dispenser that overcomes these and other drawbacks of conventional
syringe-type dispensers.
SUMMARY
[0006] According to one aspect, a dispensing syringe includes a
barrel having first and second ends, and an interior reservoir. A
piston may be slidably disposed within the reservoir and is movable
within the reservoir between first and second positions to increase
or decrease a volume at the first end of the barrel. The dispensing
syringe may further include a dispensing tip proximate the first
end of the barrel. The dispensing tip includes an outlet in fluid
communication with said reservoir for dispensing liquid material to
a substrate. At least a portion of at least one of the barrel, the
piston, or the dispensing tip comprises a material selected to
maintain operative structural integrity of the dispensing syringe
at temperatures above about 150 degrees Celsius.
[0007] The piston may have first and second ends, and the first end
may have a generally hemispherical shaped surface profile with an
elongated apex extending along a central axis of the piston. The
surface profile facilitates dispensing fluid from the first end of
the barrel when the piston is moved in a direction toward the first
end. The dispensing syringe reduces or eliminates air entrapment
and minimizes the volume of material left in the syringe after the
piston has been fully engaged with the first end of the barrel.
[0008] The piston may also include a circumferentially-extending
wiper seal located between the first and second ends of the piston.
The piston may further include one or more fluid passages defined
on the hemispherically-shaped surface. The fluid passages extend
between the first and second ends of the piston and help to reduce
the accumulation of air beneath the first wiper when the interior
reservoir is filled from the first end of the barrel. The piston
may be configured to permit gas to pass from the first volume,
while retaining liquid within the first volume. In one embodiment,
at least a portion of the piston is textured to facilitate passing
gas from the first volume, while retaining the liquid.
[0009] The syringe barrel may include a radially inwardly extending
ledge within the interior reservoir. The ledge engages the wiper
seal when the piston is moved toward the first end of the barrel to
engage the piston with the first end. Engagement between the wiper
seal and the ledge squeezes liquid material from beneath the wiper,
thereby minimizing liquid material remaining in the reservoir when
the piston is moved to the first end of the barrel.
[0010] An adapter may be used for coupling the dispensing syringe
to a source of pressurized air. The adapter may include a first end
for coupling to a syringe barrel and a second end for coupling to
the source of pressurized air. First and second hubs on the first
end of the adapter engage ears on the barrel to secure the adapter
to the barrel. The ears of the barrel may have radial extents that
are small compared to the circumferential lengths of the ears, so
that deflection of the ears is reduced or eliminated during use of
the dispensing syringe. The adapter may further include a seal
extending from the first end of the adapter for engaging the open
end of the barrel when the first and second hubs engage the ears on
the barrel.
[0011] An end cap may be used with the syringe barrel when the
adapter is not used to couple the syringe barrel to a source of
pressurized air.
[0012] A tip cap may be secured to a male luer connector at the
first end of the syringe barrel. The tip cap could include an end
wall with a skirt and an annular boot extending axially outward
from the end wall. The boot is positioned concentrically within the
skirt to define a space for frictionally gripping the male luer
connector therein.
[0013] In another aspect, at least a portion of at least one of the
components of the syringe may comprise a material selected to
maintain the structural integrity of the syringe at elevated
temperatures. For example, one or more of the syringe barrel,
piston, or luer coupling may comprise a material that is capable of
maintaining the structural integrity of the syringe at elevated
temperatures. Moreover, one or more of a tip cap, end cap, or
adapter for coupling the syringe barrel to a source of pressurized
air may comprise a material that is capable of maintaining the
structural integrity of the syringe at elevated temperatures.
[0014] These and other features, objects and advantages will become
more readily apparent to those skilled in the art in view of the
following detailed description, taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate exemplary
embodiments and, together with the general description given above,
and the detailed description given below, serve to explain
principles of the invention.
[0016] FIG. 1 is a perspective view of an exemplary dispensing
syringe.
[0017] FIG. 2 is an exploded perspective view of the dispensing
syringe of FIG. 1.
[0018] FIG. 3 is a side elevation view of the barrel of the
dispensing syringe of FIG. 1.
[0019] FIG. 3A is an enlarged cross-sectional view of the syringe
barrel of FIG. 3, taken along line 3A-3A.
[0020] FIG. 3B is an enlarged cross-sectional view of an
alternative embodiment of the syringe barrel of FIG. 3.
[0021] FIG. 4 is a perspective view of an exemplary end cap for use
with the syringe barrel of FIG. 3.
[0022] FIG. 4A is a cross-sectional view of the end cap of FIG. 4,
taken along line 4A-4A.
[0023] FIG. 5 is a perspective view of an exemplary tip cap for use
with the syringe barrel of FIG. 3.
[0024] FIG. 5A is a cross-sectional view illustrating the tip cap
of FIG. 5 on the syringe barrel of FIG. 3.
[0025] FIG. 6 is a side elevation view of an exemplary adapter, as
shown in FIGS. 1-2, for use with the syringe barrel of FIG. 3.
[0026] FIG. 6A is a cross-sectional view of the adapter of FIG. 6,
taken along line 6A-6A.
[0027] FIG. 7 is a cross-sectional view illustrating the piston of
the syringe of FIG. 1 at the first end of the syringe barrel.
DETAILED DESCRIPTION
[0028] FIGS. 1, 2, 3, 3A, and 3B illustrate an exemplary liquid
dispensing syringe 10. The syringe 10 comprises a generally
elongate syringe barrel 12 having a first end 14 for dispensing
liquid material therefrom, and a second end 16 opposite the first
end 14. The barrel 12 defines an interior reservoir 18 (FIG. 3) for
containing the liquid material to be dispensed from the first end
14. A piston 20 is slidably disposed within the interior reservoir
18 and is slidably movable therein between the first and second
ends 14, 16 to thereby dispense liquid material from the first end
14 as the piston 20 moves in a direction toward the first end 14. A
dispensing tip 22 is removably coupled to the first end 14 of the
barrel 12 for communication with the interior reservoir 18 such
that liquid material may be dispensed from an outlet 24 of the
dispensing tip 22.
[0029] In the embodiment shown, the first end 14 of the barrel 12
includes a male luer connector 26 adapted to receive a
corresponding female luer 28 provided on the dispensing tip 22,
whereby the dispensing tip 22 may be coupled to the first end 14 of
the barrel 12, as depicted in FIGS. 3, 3A, and 3B. Male luer
connector 26 includes a male connecting tip 29 and a collar 30 with
internal threads 31 for securing the dispensing tip 22 thereto. The
second end 16 of the barrel 12 includes a comparatively large
diameter opening 70 and has radially outwardly extending flanges or
"ears" 74, 76 for securing an end cap 110 or an adapter 80 that
facilitates coupling the second end 16 of the barrel 12 to an
actuator such as a source of pressurized air 36 (FIG. 1).
[0030] While many different pistons could be used, an example of
one piston 20 is shown with reference to FIGS. 2 and 7, an
exemplary piston 20 is shown. The piston 20 includes a first end 32
configured to force liquid material through the first end 14 of the
barrel 12 and into the dispensing tip 22. The first end 32 of the
piston 20 mates with the first end 14 of the barrel 12 to force
liquid material into the dispensing tip 22. The second, opposite
end 34 of the piston 20 is exposed to an actuator, such as the
source of pressurized air 36 (FIG. 1), whereby the piston 20 may be
actuated in a direction from the second end 16 of the barrel 12
toward the first end 14 of the barrel 12. At least one first
circumferential wiper 40 extends radially outwardly from a
hemispherically-shaped surface 38 of the piston 20 to sealingly
engage the interior walls of the barrel 12. The wiper 40 may be in
the form of a flange or skirt extending circumferentially around
the body of the piston 20 and forms a step 41 relative to the
hemispherically-shaped surface 38. The step 41 is believed to be
important to providing a minimum dead volume within the interior
reservoir 18. A second wiper 42 may be provided near the second end
34 of the piston 20, and may be formed generally the same as the
first wiper 40 to sealingly engage the interior surface of the
barrel 12.
[0031] The surface of the piston 20, at least proximate the first
and second wipers 40, 42, and optionally in the region 43 between
the first and second wipers 40, 42, may be configured to facilitate
micro-venting of gaseous material, such as air that may be trapped
within the interior reservoir 18, while preventing liquid material
from escaping the interior reservoir 18. For example, the first
wiper 40, the second wiper 42, and/or the region 43 may be textured
in such a way that gaseous material may pass from the interior
reservoir 18, but liquid material is retained in the interior
reservoir 18. Alternatively, some or all of the piston 20 may be
formed from material that is permeable to gases, but impermeable to
liquids to facilitate passing gaseous materials from the internal
reservoir 18. It will be appreciated that various other methods may
be used to facilitate passing gaseous material from the internal
reservoir 18, while preventing liquid material from escaping. The
region 43 may also have a concave profile to minimize material
shear and pressure, and to minimize entrapping gas between the
first and second wipers 42, 43.
[0032] With continued reference to FIGS. 2 and 7, the first end 32
of the piston 20 has a smooth radial profile defining a generally
hem ispherically-shaped surface 38 that more evenly distributes
pressure throughout the liquid material as the piston 20 is moved
toward the first end 14 of the barrel 12 to dispense liquid
material from the tip 22, and minimizes shear in the liquid
material. In the embodiment shown, an apex 44 of the piston 20
forms a tip at the first end 32 of the piston 20. The apex 44 can
be elongated along a central axis 45 of the piston 20 such that the
apex 44 extends outwardly from the hemispherical surface 38 and can
thereby extend downwardly into a portion of the male luer 26 when
the piston 20 is engaged with the second end 14 of the barrel 12.
The elongated apex 44 includes a curved region 44a that provides a
smooth transition from the hemispherically-shaped surface 38 and
forms a bullet-nose shape, for example. This elongated apex 44 of
the piston 20 helps to dispense liquid material through the
dispensing tip 22 and minimizes waste retained within the dispenser
10.
[0033] The piston 20 may further include flow passages 46 defined
on the hemispherically-shaped surface 38 of the piston 20, between
the apex 44 and the first wiper 40. The flow passages 46 may be
defined by channels formed into the outer surface 38 of the piston
20, or they may be defined by outwardly extending ribs or surfaces
(not shown) disposed on the first end 32 of the piston 20. In the
embodiment shown, the flow passages 46 are channels formed into the
first end 32 of the piston 20 and are approximately 0.003 to 0.005
inch deep.
[0034] When the barrel reservoir 18 is filled from the first end 14
of the barrel 12, liquid material is directed along the flow
passages 46 from the apex 44 of the piston 20 toward the first
wiper 40. The movement of liquid material along flow passages 46
forces entrapped air toward the first wiper 40 where the air may
pass through. The wiper 40, however, prevents the liquid material
from material from passing. In this way, the accumulation of air
beneath the first wiper 40 is reduced or eliminated.
[0035] In the embodiments illustrated in FIGS. 3A-3B, the first end
14 of the syringe barrel 12 and a dispensing tip 22 are shown in
more detail. The barrel 12 cooperates with the design of the
dispensing tip 22 to minimize the shear of liquid material and to
reduce or eliminate the formation of air pockets within the barrel
reservoir 18 during filling and/or dispensing operations. To this
end, the first end 14 of the barrel 12 includes a smoothly curved
profile 48 corresponding to the hemispherically-shaped surface 38
of the first end 32 of the piston 20. In one embodiment, the curved
profile 48 may include a radius in the range of about 5/32-inch to
about 3/16-inch, or greater. The curved profile 48 helps to direct
liquid material through an outlet passageway 50 and outlet orifice
52 at the first end 14 of the barrel 12 to provide smooth
transition into the inlet 54 of the dispensing tip 22. The inner
diameter of the outlet passageway 50 may be tapered to minimize
shear in the liquid material as it is dispensed from the barrel 12
into the dispensing tip 22. In the embodiment depicted in FIG. 3A,
the outlet orifice 52 of the syringe barrel 12 has a relatively
blunt shape. Alternatively, the outlet orifice 52a of the barrel 12
may be flared gradually outwardly toward the interior of the
dispensing tip inlet 54 to provide a smooth transition between the
first end 14 of the barrel 12 and the dispensing tip 22, as
depicted in FIG. 3B. The interior of the dispensing tip inlet 54
may have generally frustoconically-shaped sidewalls or
"bullet-nose"-shaped sidewalls to minimize entrapment of air within
the dispensing tip 22, and to provide a generally smooth transition
between the inlet 54 of the dispensing tip 22 and the outlet
passageway 56.
[0036] With continued reference to FIG. 3A, the outlet passageway
50 of the syringe barrel 12 extends over a circumferential groove
60 formed in the inlet 54 of the dispensing tip 22. This groove 60,
or "stripper ring" is formed into the dispensing tip 22 during a
molding process and helps to retain the dispensing tip 22 on one
half of a removable core member as the other half of the core is
removed from the molded tip 22. The tip 22 is subsequently ejected
from the core member and the stripper ring 60 remains within the
inlet passageway of the dispensing tip 22.
[0037] The first end 14 of the syringe barrel 12 further includes
an interior ledge 62 adapted to engage the first wiper 40 on the
piston 22 as the piston 22 engages the interior surface at the
first end 14 of the barrel 12. As the interior ledge 62 engages the
first wiper 40, liquid material beneath the wiper 40 is further
forced from the wiper 40, thereby reducing liquid material waste.
In the embodiment shown, the barrel 12 is provided with a uniform
wall thickness such that the interior ledge 62 creates a
corresponding radially outwardly extending ledge 64 on the exterior
surface of the barrel 12, giving a distinctive visual appearance to
the first end 14 of the syringe barrel 12.
[0038] With continued reference to FIGS. 2 and 3, the second end 16
of the syringe barrel 12 includes a relatively large diameter
opening 70 and has a radially outwardly extending flange 72. A pair
oppositely disposed tabs or ears 74, 76 extend radially outwardly
from the flange 72, in opposite directions, to facilitate securing
an end cap 110 or an adapter 80 for coupling the syringe 10 to an
actuator, as will be described in more detail below. The radially
extending length of the ears 74, 76 is generally smaller than
conventional syringe ears to minimize flexure of the ears 74, 76
during use. This flexure can cause variations in dispensed volumes
of liquid material when a pressure pulse is applied to the syringe
10 to cause the piston 20 to move in a direction toward the first
end 14 of the barrel 12. Repeated flexure of the ears 74, 76 over
time can fatigue the material of the barrel 12, thereby further
increasing deflection of the ears 74, 76 and the variation in
dispensed volumes of liquid material. Advantageously, the reduced
lengths of the ears 74, 76 in the syringe 10 of the embodiment
shown reduces the flexure of the ears 74, 76 thereby improving the
consistency of the volumes of liquid material dispensed from the
syringe 10. In the embodiment shown, each ear 74, 76 further
includes a radially outwardly extending detent or bump 78, formed
on an outer periphery thereof, to provide positive engagement with
an end cap 110 or an adapter 80 which may be coupled to the second
end 16 of the barrel 12, as described in more detail below.
[0039] FIGS. 6 and 6A illustrate an exemplary adapter 80 configured
to be coupled to the second end 16 of the syringe barrel 12 to
facilitate coupling the syringe 10 to an actuator, such as a source
of pressurized air 36. In the embodiment shown, the adapter 80
includes a first end 82 adapted to be coupled to the second end 16
of the barrel 12, and a second end 84 adapted to be coupled to a
conduit (not shown) which communicates with a source of pressurized
air 36. The second end 84 of the adapter may include a barb 86 to
facilitate securing the conduit thereto. The first end 82 of the
adapter 80 includes first and second oppositely disposed hubs 88,
90 for engaging the first and second ears 74, 76 at the second end
16 of the barrel 12, in a bayonet-type fashion. Each hub 88, 90 is
defined by a radially extending rim 92, an end wall 94 spaced from
the rim 92, and a circumferentially extending sidewall 96 extending
therebetween. The end wall 94 has an interior surface 98 (FIG. 6A)
that is sloped in a direction toward the rim 92 to draw the adapter
80 tightly against the second end 16 of the barrel 12 as the
adapter 80 is twisted to receive the ears 74, 76 within the
respective hubs 88, 90 of the adapter.
[0040] With continued reference to FIGS. 6 and 6A, and referring to
FIG. 2, the first end 82 of the adapter 80 further includes a seal
100 disposed on a centrally located cylindrical boss 102 that
protrudes from the end wall 94 in a direction opposite the second
end 84. A radially outwardly extending flange 104 retains the seal
100 on the cylindrical boss 102. In the embodiment shown, seal 100
is an O-ring, but it will be appreciated that various other types
of sealing devices may alternatively be used. When mounted to the
syringe barrel 12, the seal extends axially within the second end
16 of the syringe barrel 12 to engage an interior surface of the
syringe barrel 12. To fully engage the seal 100 with the interior
surface of the syringe barrel 12, the adapter 80 must be rotated to
receive the ears 74, 76 of the syringe barrel 12 within the hubs
88, 90 of the adapter 80. As the ears 74, 76 are received within
the hubs 88, 90 of the adapter 80, the sloped surface 98 of the end
wall 94 draws the seal 100 into the second end 16 of the barrel 12
and the seal 100 sealingly engages the interior surface of the
syringe barrel 12.
[0041] Prior to twisting the adapter 80 to receive the ears 74, 76
within the hubs 88, 90 of the adapter 80, air can escape from the
interior of the reservoir 18 past the seal 100. When the ears 74,
76 are positioned fully within the hubs 88, 90 of the adapter 80,
the detents 78 formed on the ears 74, 76 engage corresponding slots
79 (FIG. 6A) formed into the side walls 96 of the adapter 80 to
provide a snap fit of the adapter 80 to the ears 74, 76 of the
barrel 12, thereby providing a positive indication that the adapter
80 is fully locked onto the second end 16 of the barrel 12. In the
embodiment shown, the slots 79 are formed by apertures 79a formed
through the end walls 94 and extending into the sidewalls 96.
[0042] The seal 100 engages a chamfer 106 (FIG. 3) formed on the
second end 16 of the syringe barrel and adjacent the opening 70.
Location of the chamfer 106 at the opening 70 ensures that seal 100
will not extend too far into the syringe barrel 12 and thereby
provides an indication of whether the adapter 80 is properly seated
and locked onto the syringe barrel 12. When the adapter 80 is not
properly seated and locked, the adapter 80 will easily slip off of
the second end 16 of the syringe barrel 12 due to the shallow
engagement of the seal 100 with chamfer 106.
[0043] FIGS. 4 and 4A depict an end cap 110 that may be secured to
the second end 16 of the syringe barrel 12, in place of adapter 80.
The end cap 110 includes an annular brim 112 and first and second
oppositely disposed flanges 114, 116 extending generally radially
outwardly from the brim 112. First and second oppositely disposed
engagement tabs 118, 120, similar to the hubs 88, 90 of the adapter
80, extend from a bottom side of the brim 112 for engaging the ears
74, 76 of the barrel 12. Each engagement tab 118, 120 comprises a
sidewall 122 extending perpendicular to the brim 112, and an end
wall 124 extending parallel to the brim 112. The end wall 124, brim
112, and sidewall 122 thereby define generally circumferentially
extending slots adapted to receive the first and second ears 74, 76
provided on the second end 16 of the syringe barrel 12.
[0044] The end cap 110 further comprises a generally hat-shaped
central portion 130 defined by first and second concentric
sidewalls 132, 134 and an end wall 136. The first sidewall 132
extends axially from the brim 112 and is joined to the second
sidewall 134 by an arcuate end portion 138 extending therebetween.
The end wall 136 is provided on the second end of the second
sidewall 134 and closes the cap. The central portion 130 of the end
cap 110 permits the brim 112 to flex, thereby facilitating closure
of the second end 14 of the syringe barrel 12 with the end cap 110.
A generally circumferentially extending sealing bead 140 is
disposed on the first sidewall 132 of the central portion 130 to
provide sealing engagement of the end cap 110 with an interior
surface of the syringe barrel 12. An elongate stem 142 is centrally
located on the end wall 136 and extends downwardly from the end
wall 136. Stem 142 facilitates the formation of the end wall 136
during manufacture. To seal the second end 14 of the barrel 12 with
the end cap 110, the first tab 118 is engaged with the first ear 74
at the second end 14 of the barrel 12, and the second tab 120 is
pivoted downwardly to snap over the second ear 76 while compressing
the central portion 130 to cause the second tab 120 to flexibly
extend over the second ear 76.
[0045] FIGS. 5 and 5A depict an exemplary tip cap 150 that may be
used with the syringe 10. The tip cap 150 is configured to fit over
the male luer 26 at the first end 14 of the syringe barrel 12. In
the embodiment shown, the tip cap 150 includes a generally circular
end wall 152, although it will be appreciated that the end wall 152
may have various other shapes. The end wall 152 may have flutes,
lobes, or other features disposed around its outer periphery to
facilitate gripping the tip cap 150 during installation or removal
of the tip cap 150 from the syringe barrel 12. A generally
cylindrical skirt 154 extends from the end wall 152 and is sized to
be received over the collar 30 of the male luer 26. A generally
cylindrical boot 156 also extends from the end wall 152 and is
located concentrically within the skirt 154 to be received between
the male connecting tip 29 and the collar 30 of the male luer 26.
The skirt 154 and boot 156 are sized and dimensioned to provide a
frictional fit on the male luer 26 such that the tip cap 150 is
retained on the first end 14 of the syringe barrel 12. When the tip
cap 150 is firmly seated on the male luer 26 of syringe barrel 12,
a raised, central bead 160 disposed on an interior side of the end
wall 152 sealingly engages the outlet orifice 52 at the first end
14 of the syringe barrel 12.
[0046] The tip cap may 150 further include one or more
circumferentially extending ribs or ridges 158 provided on the boot
156 and sized to engage the threads of the male luer 26. The ribs
158 may be configured such that the tip cap 150 can be pressed
axially onto the first end 14 of the syringe barrel 12, whereby the
boot 156 deforms radially inwardly so that the ribs 158 ride over
the threads 31 on the male luer 26. Alternatively, the tip cap 150
may be placed onto the first end 14 of the syringe barrel 12 by
twisting the tip cap 150 to advance the tip cap 150 over the
threads of the male luer 26. The tip cap 150 may be removed from
the first end 14 of the syringe barrel 12 by twisting the tip cap
150.
[0047] In accordance with another aspect of the principles of the
present invention, at least a portion of one or more of the
components of a dispensing syringe may comprise a material selected
to maintain the structural integrity of the dispensing syringe at
elevated temperatures such that the dispensing syringe operates as
intended at such elevated temperatures. Accordingly, the dispensing
syringe may be used to dispense liquid materials, such as, but not
limited to, hot melt adhesives that require heating to elevated
temperatures. As a non-limiting example, a dispensing syringe in
accordance with the principles of the present invention may be used
to dispense polyurethane hot melt adhesive (PUR) at elevated
temperatures such as up to about 150 degrees Celsius. In another
embodiment, the material may be selected to maintain structural
integrity at elevated temperatures up to about 200 degrees Celsius.
In yet another embodiment, the material may be selected to maintain
structural integrity at elevated temperatures above about 200
degrees Celsius. Because one or more of the components of the
dispensing syringe, such as the barrel, the piston, or the luer
coupling, are formed from a material that maintains structural
integrity at elevated temperatures, these components will not
soften to a degree that structural integrity of the syringe is
compromised, thereby avoiding problems such as leaking or bursting
under pressure.
[0048] In one embodiment, one or more of the components of the
dispensing syringe 10 may comprise a resin that is resistant to
elevated temperatures. For example, one or more of the components,
such as the barrel 12, piston 20, dispensing tip 22, or luer
connector 26 may comprise polybutylene terephthalate (PBT) or any
other material suitable for maintaining the structural integrity of
the components at elevated temperatures so that the intended
operation of the dispensing syringe 10 is not adversely affected.
Moreover, various other components of a dispensing syringe 10, such
as a tip cap 150, an adapter 80, an end cap 110, or any other
component of a dispensing syringe, or any component usable with a
dispensing syringe, may comprise polybutylene terephthalate (PBT)
or any other material suitable for maintaining the structural
integrity of the components at elevated temperatures. The material
may further include additives to improve characteristics or
performance of the material during use. For example, the material
may be a composite material including reinforcing fibers, such as,
but not limited to glass fibers, to improve the strength of the
material. While the material is described herein as including
reinforcing fibers, it will be appreciated that a composite
material formed with other reinforcing material may alternatively
be used.
[0049] In another aspect, one or more of the components of the
dispensing syringe 10 may comprise a material that includes
additives to improve resistance of the material to flames or
ultraviolet radiation (UV), as may be desired. Moreover, various
other components of the dispensing syringe 10, such as the adapter
80, end cap 110, or tip cap 150, may also comprise material that
maintains structural integrity at elevated temperatures, including
additives as discussed above, so that the intended operation of the
dispensing syringe 10 is not adversely affected.
[0050] While the present invention has been illustrated by the
description of various exemplary embodiments thereof, and while the
embodiments have been described in considerable detail, they are
not intended to restrict or in any way limit the scope of the
appended claims to such detail. The various features discussed
herein may be utilized alone or in any combination. Additional
advantages and modifications will readily appear to those skilled
in the art. The invention in its broader aspects is therefore not
limited to the specific details, representative apparatus and
method and illustrative examples shown and described. Accordingly,
departures may be made from such details without departing from the
scope of the general inventive concept.
* * * * *