U.S. patent number RE40,539 [Application Number 10/948,850] was granted by the patent office on 2008-10-14 for fluid pump and cartridge.
This patent grant is currently assigned to DL Technology LLC. Invention is credited to Jeffrey P. Fugere.
United States Patent |
RE40,539 |
Fugere |
October 14, 2008 |
Fluid pump and cartridge
Abstract
In a fluid pump and cartridge assembly, a cartridge includes a
material inlet port, a material outlet port, and a feed screw. The
feed screw delivers fluid to be dispensed from the fluid inlet to
the outlet port. The fluid inlet is preferably elongated in a
direction along a longitudinal axis of the feed screw to enhance
consistency in material flow through the cartridge. The feed screw
is preferably driven by a closed-loop servo motor to achieve
high-performance dispensing resolution. The assembly is preferably
compatible with fixed-z and floating-z cartridges.
Inventors: |
Fugere; Jeffrey P. (Hampton
Falls, NH) |
Assignee: |
DL Technology LLC (Haverhill,
MA)
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Family
ID: |
39828496 |
Appl.
No.: |
10/948,850 |
Filed: |
September 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60186783 |
Mar 3, 2000 |
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60163952 |
Nov 8, 1999 |
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Reissue of: |
09702522 |
Oct 31, 2000 |
06511301 |
Jan 28, 2003 |
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Current U.S.
Class: |
417/359; 222/251;
222/388 |
Current CPC
Class: |
B05C
11/10 (20130101); B05C 11/1034 (20130101); B05C
17/00503 (20130101); F04B 53/16 (20130101); F04B
53/22 (20130101) |
Current International
Class: |
F04B
35/00 (20060101); F04B 17/00 (20060101) |
Field of
Search: |
;417/205,360,410.3
;418/220 ;222/412,413,325,327,390,391 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Karassik et al., "Pump Handbook" end Ed., McGraw Hill Inc., 1986,
pp. 9.30. cited by examiner.
|
Primary Examiner: Kramer; Devon
Assistant Examiner: Dwivedi; Vikansha
Attorney, Agent or Firm: Mills & Onello, LLP
Parent Case Text
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
No. 60/186,763, filed Mar. 3, 2000 and U.S. Provisional Application
No. 60/163,952, filed Nov. 8, 1999 the contents of which are
incorporated herein by reference, in their entirety.
Claims
I claim:
1. A fluid dispensing pump comprising: a feed screw having a
helical cavity defined between a major diameter and a minor
diameter of a thread of the feed screw; a cartridge body.Iadd., the
cartridge body and the feed screw comprising a detachable cartridge
unit, the cartridge unit .Iaddend.having a feed port in
communication with the feed screw for introduction of dispensing
fluids into the helical cavity; .[.and.]. .Iadd.a pump housing
including a cartridge cavity, the cartridge cavity having a
mounting location at which the cartridge unit including both the
cartridge body and the feed screw is inserted into and removed from
the cartridge cavity, the pump housing releasibly securing the
cartridge unit in the cartridge cavity, the cartridge unit having a
motor interface at a first end of the cartridge unit and a fluid
outlet and a second end of the cartridge unit opposite the first
end, the cartridge unit including a fluid path between the feed
port and the fluid outlet; .Iaddend. a closed-loop
servo-motor.Iadd., the servo-motor .Iaddend.having indexed
rotational positions .[.for controlling rotational position of the
feed screw during a dispensing operation.]. .Iadd., the servo-motor
including a rotary encoder that generates a data signal related to
the rotational position of the feed screw, and the motor interface
of the cartridge unit being releasably coupled to the servo-motor
when the cartridge unit is inserted into the cartridge cavity; and
a motor controller that receives the rotational position data
signal from the encoder, and, in response, transmits a control
signal to the servo-motor for controlling the rotary position and
rotational velocity of the feed screw during a dispensing
operation, to control a flow of dispensing fluid in the fluid path
through the feed port to the fluid outlet during the dispensing
operation.Iaddend..
2. The pump of claim 1 wherein the cartridge body comprises a first
outer body, and a second inner body, the feed port further
comprising a feed cavity that is formed in the inner body.
3. The pump of claim 1 wherein the closed-loop servo motor further
comprises a positional encoder.
4. The pump of claim 1 further comprising a transmission coupled
between the motor and feed screw for gearing the feed screw
relative to the motor.
5. The pump of claim 1 further comprising a notch on an outer
surface of the cartridge body adapted to mate with a pin mounted to
.[.a.]. .Iadd.the .Iaddend.pump .[.body.]. .Iadd.housing
.Iaddend.for securing the cartridge body to the pump .[.body.].
.Iadd.housing.Iaddend..
6. The pump of claim 5 wherein the notch comprises a groove for
allowing translation of the cartridge body relative to the pump
.[.body.]. .Iadd.housing .Iaddend.over the length of the
groove.
7. The pump of claim 5 wherein the notch comprises a hole for
fixing the longitudinal position of the cartridge body relative to
the pump .[.body.]. .Iadd.housing.Iaddend..
8. The pump of claim 5 further comprising a cartridge release lever
for releasibly engaging the pin such that the cartridge body can be
released from the pump .[.body.]. .Iadd.housing.Iaddend..
9. The pump of claim 5 further comprising a fluid container
retention arm on the pump .[.body.]. .Iadd.housing .Iaddend.for
releasibly securing a fluid container to the pump .[.body.].
.Iadd.housing.Iaddend..
10. The pump of claim 9 wherein the retention arm is adapted to
clasp a neck of a syringe.
11. The pump of claim 5 further comprising a pump release bracket
for releasibly mounting the pump .[.body.]. .Iadd.housing
.Iaddend.to a pump dispensing frame.
12. The pump of claim 1 wherein the feed port comprises a feed
cavity that is positioned along a side portion of the feed
screw.
.[.13. The pump of claim 12 wherein the feed port comprises a
cavity that is elongated in a direction substantially along a
longitudinal axis of the feed screw..].
.[.14. The pump of claim 12 wherein the feed port comprises a
cavity that is elongated in a direction substantially parallel to a
longitudinal axis of the feed screw..].
15. The pump of claim .[.13.]. .Iadd.2 .Iaddend.wherein the inner
body comprises carbide.
.[.16. The pump of claim 1 wherein the feed port comprises a feed
cavity that is positioned at a top portion of the feed
screw..].
17. A fluid dispensing pump comprising: a feed screw having a
helical cavity defined between a major diameter and a minor
diameter of a thread of the feed screw; a cartridge body having a
feed cavity in communication with the feed screw for introduction
of dispensing fluids into the helical cavity, the cartridge body
having a notch on an outer surface adapted to mate with a pin
mounted to a pump body .[.for securing.]. .Iadd.to releasibly
secure .Iaddend.the cartridge body .Iadd.and the feed screw
.Iaddend.to the pump body; and a .[.motor.]. .Iadd.closed-loop
servo-motor .Iaddend.having indexed rotational positions for
controlling rotational position of the feed screw during a
dispensing operation.Iadd., the servo-motor including a rotary
encoder that generates a feedback signal related to the rotational
position of the feed screw.Iaddend..
18. The pump of claim 17 wherein the notch comprises a groove for
allowing translation of the cartridge body relative to the pump
body over the length of the groove.
19. The pump of claim 17 wherein the notch comprises a hole for
fixing the longitudinal position of the cartridge body relative to
the pump body.
20. The pump of claim 17 further comprising a cartridge release
lever for releasibly engaging the pin such that the cartridge body
can be released from the pump body.
21. The pump of claim 17 further comprising a fluid container
retention arm on the pump body for releasibly securing a fluid
container to the pump body.
22. The pump of claim 21 wherein the retention arm is adapted to
clasp a neck of a syringe.
23. The pump of claim 17 further comprising a pump release bracket
for releasibly mounting the pump body to a pump dispensing
frame.
24. The pump of claim 17 wherein the feed cavity is positioned
along a side portion of the feed screw.
.[.25. The pump of claim 17 wherein the feed cavity is positioned
at a top portion of the feed screw..].
.[.26. The pump of claim 24 wherein the feed cavity is elongated in
a direction substantially along a longitudinal axis of the feed
screw..].
.[.27. The pump of claim 24 wherein the feed cavity is elongated in
a direction substantially parallel to a longitudinal axis of the
feed screw..].
28. The pump of claim 17 wherein the cartridge body comprises a
first outer body, and a second inner body, the feed cavity being
formed in the inner body.
29. The pump of claim 28 wherein the inner body comprises
carbide.
30. The pump of claim 17 wherein the motor comprises a closed-loop
servo-motor having a positional encoder.
31. The pump of claim 17 further comprising a transmission coupled
between the motor and feed screw for gearing the feed screw
relative to the motor.
32. A fluid dispensing pump comprising: a feed screw having a
helical cavity defined between a major diameter and a minor
diameter of a thread of the feed screw; a cartridge body.Iadd., the
cartridge body and the feed screw comprising a detachable cartridge
unit, the cartridge unit .Iaddend.having a feed cavity in
communication with the feed screw .[.and positioned at a top
portion of the feed screw.]. for introduction of dispensing fluids
into the helical cavity; .[.and.]. .Iadd.a pump housing including a
cartridge cavity, the cartridge cavity having a mounting location
at which the cartridge unit including both the cartridge body and
the feed screw is inserted into and removed from the cartridge
cavity, the pump housing releasibly securing the cartridge unit in
the cartridge cavity, the cartridge unit having a motor interface
at a first end of the cartridge unit and a fluid outlet at a second
end of the cartridge unit opposite the first end, the cartridge
unit including a fluid path between the feed cavity and the fluid
outlet; .Iaddend. a .[.motor.]. .Iadd.closed-loop servo-motor
.Iaddend.having indexed rotational positions for controlling
rotational position of the feed screw during a dispensing
operation.Iadd., the servo-motor including a rotary encoder that
generates a feedback signal related to the rotational position of
the feed screw, and the motor interface of the cartridge unit being
releasibly coupled to the servo-motor when the cartridge unit is
inserted into the cartridge cavity; and a programmable motor
controller that transmits control signals to the servo-motor to
control the rotational position of the feed screw in response to
the feedback signal, to control a flow of dispensing fluid in the
fluid path through the feed cavity to the fluid outlet during the
dispensing operation.Iaddend..
33. The pump of claim 32 wherein the cartridge body comprises a
first outer body, and a second inner body, the feed cavity being
formed in the inner body.
34. The pump of claim 33 wherein the inner body comprises
carbide.
35. The pump of claim 32 wherein the .[.motor comprises a.].
closed-loop servo-motor .[.having.]. .Iadd.comprises .Iaddend.a
positional encoder.
36. The pump of claim 32 further comprising a transmission coupled
between the motor and feed screw for gearing the feed screw
relative to the .Iadd.servo-.Iaddend.motor.
37. The pump of claim 32 further comprising a notch on an outer
surface of the cartridge body adapted to mate with a pin mounted to
.[.a.]. .Iadd.the .Iaddend.pump .[.body.]. .Iadd.housing
.Iaddend.for securing the cartridge body to the pump .[.body.].
.Iadd.housing.Iaddend..
38. The pump of claim 37 wherein the notch comprises a groove for
allowing translation of the cartridge body relative to the pump
.[.body.]. .Iadd.housing .Iaddend.over the length of the
groove.
39. The pump of claim 37 wherein the notch comprises a hole for
fixing the longitudinal position of the cartridge body relative to
the pump .[.body.]. .Iadd.housing.Iaddend..
40. The pump of claim 37 further comprising a cartridge release
lever for releasibly engaging the pin such that the cartridge body
can be released from the pump .[.body.].
.Iadd.housing.Iaddend..
41. The pump of claim 37 further comprising a fluid container
retention arm on the pump .[.body.]. .Iadd.housing .Iaddend.for
releasibly securing a fluid container to the pump .[.body.].
.Iadd.housing.Iaddend..
42. The pump of claim 41 wherein the retention arm is adapted to
clasp a neck of a syringe.
43. The pump of claim 37 further comprising a pump release bracket
for releasibly mounting the pump .[.body.]. .Iadd.housing
.Iaddend.to a pump dispensing frame.
44. A fluid dispensing pump comprising: a feed screw having a
helical cavity defined between a major diameter and a minor
diameter of a thread of the feed screw; a cartridge body.Iadd., the
cartridge body and the feed screw comprising a detachable cartridge
unit, the cartridge unit .Iaddend.having a feed port in
communication with the feed screw for introduction of dispensing
fluids into the helical cavity; .[.and.]. .Iadd.a pump housing
including a cartridge cavity, the cartridge cavity having a
mounting location at which the cartridge unit including both the
cartridge body and the feed screw is inserted into and removed from
the cartridge cavity, the pump housing releasibly securing the
cartridge unit in the cartridge cavity, the cartridge unit having a
motor interface at a first end of the cartridge unit and a fluid
outlet at a second end of the cartridge unit opposite the first
end, the cartridge unit including a fluid path between the feed
port and the fluid outlet; .Iaddend. a .Iadd.closed-loop
servo-.Iaddend.motor having indexed rotational positions for
controlling rotational position of the feed screw during a
dispensing operation, .[.the motor being.]. .Iadd.the motor
interface of the cartridge unit being releasably coupled to the
servo-motor when the cartridge unit is inserted into the cartridge
cavity; and a programmable motor controller .Iaddend.in
communication with .[.a controller.]. .Iadd.the closed-loop
servo-motor .Iaddend.that receives a feedback signal from the
.Iadd.servo-.Iaddend.motor related to the rotational position of
the feed screw.Iadd., and, in response, generates control signals
that are transmitted to the servo-motor for controlling the rotary
position and rotational velocity of the feed screw during a
dispensing operation, to control a flow of dispensing fluid in the
fluid path through the feed port to the fluid outlet during the
dispensing operation.Iaddend..
.[.45. The pump of claim 44 wherein the feed port comprises a feed
cavity that is elongated in a direction substantially along a
longitudinal axis of the feed screw..].
.[.46. The pump of claim 44 wherein the feed port comprises a feed
cavity that is elongated in a direction substantially parallel to a
longitudinal axis of the feed screw..].
47. The pump of claim 44 wherein the cartridge body comprises a
first outer body, and a second inner body, the feed port comprising
a feed cavity that is formed in the inner body.
48. The pump of claim 47 wherein the inner body comprises
carbide.
49. The pump of claim 44 wherein the .[.motor comprises a.].
closed-loop servo-motor .[.having.]. .Iadd.comprises .Iaddend.a
positional encoder.
50. The pump of claim 44 further comprising a transmission coupled
between the motor and feed screw for gearing the feed screw
relative to the .Iadd.servo-.Iaddend.motor.
51. The pump of claim 44 wherein the feed port comprises a feed
cavity that is positioned along a side portion of the feed
screw.
.[.52. The pump of claim 44 wherein the feed port comprises a feed
cavity that is positioned at a top portion of the feed
screw..].
.Iadd.53. A fluid dispensing pump comprising: a cartridge body
having a feed screw cavity and a feed screw mounted in the feed
screw cavity, the cartridge body and the feed screw comprising a
detachable cartridge unit, the feed screw having a helical cavity
defined between a major diameter and a minor diameter of a thread
of the feed screw in which the feed screw is mounted, the cartridge
unit having a feed port in communication with the feed screw for
introduction of dispensing fluids into the helical cavity, the feed
screw including a neck that extends through a portion of the
cartridge body; a pump housing including a motor mount and a
cartridge cavity, the cartridge cavity having a cartridge mounting
location at which the cartridge unit including both the cartridge
body and the feed screw is inserted into and removed from the
cartridge cavity, the pump housing releasibly securing the
cartridge unit in the cartridge cavity, the cartridge unit
including the neck of the feed screw at a first end of the
cartridge unit and a fluid outlet at a second end of the cartridge
unit opposite the first end, the cartridge unit including a fluid
path between the feed port and the fluid outlet; and a closed-loop
servo-motor mounted at the motor mount of the pump housing, the
servo-motor having indexed rotational positions for controlling
rotational position of the feed screw during a dispensing operation
to control a flow of dispensing fluid in the fluid path through the
feed port to the fluid outlet during the dispensing operation, the
servo-motor including a drive axle that is aligned with the neck of
the feed screw, and the neck of the feed screw of the cartridge
unit being releasably coupled to the servo-motor when the cartridge
unit is inserted into the cartridge cavity..Iaddend.
.Iadd.54. The fluid dispensing pump of claim 53 wherein the drive
axle is coupled to the neck of the feed screw..Iaddend.
.Iadd.55. The fluid dispensing pump of claim 53 further comprising
a transmission coupled between, and aligned with, the drive axle of
the servo-motor and the neck of the feed screw for gearing the feed
screw relative to the servo-motor..Iaddend.
.Iadd.56. The fluid dispensing pump of claim 53 further comprising
a notch on an outer surface of the cartridge body adapted to mate
with a pin mounted to a pump housing for securing the cartridge
unit to the pump housing..Iaddend.
.Iadd.57. The fluid dispensing pump of claim 56 wherein the notch
comprises a groove for allowing translation of the cartridge body
relative to the pump housing over the length of the
groove..Iaddend.
.Iadd.58. The fluid dispensing pump of claim 56 wherein the notch
comprises a hole for fixing the longitudinal position of the
cartridge body relative to the pump housing..Iaddend.
.Iadd.59. The fluid dispensing pump of claim 56 further comprising
a cartridge release lever on the pump housing for releasibly
engaging the pin such that the cartridge unit can be released from
the pump housing..Iaddend.
.Iadd.60. The fluid dispensing pump of claim 53 wherein the motor
mount is at first end of the pump housing and wherein the cartridge
cavity includes an opening at which the cartridge body is inserted
into the pump housing at a second end of the pump housing opposite
the first end..Iaddend.
.Iadd.61. The fluid dispensing pump of claim 53 further comprising
a motor controller that transmits control signals to the
servo-motor to control the rotational position of the feed
screw..Iaddend.
.Iadd.62. The fluid dispensing pump of claim 53 wherein the
servo-motor includes a rotary encoder that generates a feedback
signal related to the rotational position of the feed
screw..Iaddend.
.Iadd.63. The fluid dispensing pump of claim 62 further comprising
a motor controller that transmits control signals to the
servo-motor to control the rotational position of the feed screw in
response to the feedback signal..Iaddend.
.Iadd.64. The fluid dispensing pump of claim 63 wherein the motor
controller transmits control signals to the servo-motor to further
control the rotational velocity of the feed screw..Iaddend.
.Iadd.65. The fluid dispensing pump of claim 63 wherein the motor
controller transmits control signals to the servo-motor to further
control the rotational acceleration of the feed screw..Iaddend.
.Iadd.66. The fluid dispensing pump of claim 53 further comprising
a pump release bracket for releasibly mounting the pump housing to
a pump dispensing frame..Iaddend.
.Iadd.67. A fluid dispensing pump comprising: a cartridge body
having a feed screw cavity and a feed screw mounted in the feed
screw cavity, the cartridge body and the feed screw comprising a
detachable cartridge unit, the feed screw having a helical cavity
defined between a major diameter and a minor diameter of a thread
of the feed screw in which the feed screw is mounted, the cartridge
unit having a feed port in communication with the feed screw for
introduction of dispensing fluids into the helical cavity; a pump
housing including a motor mount and a cartridge cavity, the motor
mount positioned at a first end of the pump housing and the
cartridge cavity including an opening at a second end of the pump
housing opposite the first end at which opening the cartridge unit
including both the cartridge body and the feed screw is inserted
into and removed from the cartridge cavity, the pump housing
releasibly securing the cartridge unit in the cartridge cavity, the
cartridge unit having a motor interface at a first end of the
cartridge unit and a fluid outlet at a second end of the cartridge
unit opposite the first end, the cartridge unit including a fluid
path between the feed port and the fluid outlet; a closed-loop
servo-motor mounted at the motor mount of the pump housing, the
servo-motor having indexed rotational positions for controlling
rotational position of the feed screw during a dispensing operation
to control a flow of dispensing fluid in the fluid path through the
feed port to the fluid outlet during the dispensing operation, the
servo-motor including a drive axle that is aligned with a
longitudinal axis of the feed screw, the motor interface of the
cartridge unit being releasably coupled to the drive axle when the
cartridge unit is inserted into the cartridge cavity..Iaddend.
.Iadd.68. The fluid dispensing pump of claim 67 wherein the feed
screw includes a neck..Iaddend.
.Iadd.69. The fluid dispensing pump of claim 68 wherein the neck
extends through a portion of the cartridge body..Iaddend.
.Iadd.70. The fluid dispensing pump of claim 68 wherein the drive
axle is coupled to the neck of the feed screw..Iaddend.
.Iadd.71. The fluid dispensing pump of claim 68 further comprising
a transmission coupled between, and aligned with, the drive axle of
the servo-motor and the neck of the feed screw for gearing the feed
screw relative to the servo-motor..Iaddend.
.Iadd.72. The fluid dispensing pump of claim 67 further comprising
a notch on an outer surface of the cartridge body adapted to mate
with a pin mounted to a pump housing for securing the cartridge
unit to the pump housing..Iaddend.
.Iadd.73. The fluid dispensing pump of claim 72 wherein the notch
comprises a groove for allowing translation of the cartridge body
relative to the pump housing over the length of the
groove..Iaddend.
.Iadd.74. The fluid dispensing pump of claim 72 wherein the notch
comprises a hole for fixing the longitudinal position of the
cartridge body relative to the pump housing..Iaddend.
.Iadd.75. The fluid dispensing pump of claim 72 further comprising
a cartridge release lever on the pump housing for releasibly
engaging the pin such that the cartridge unit can be released from
the pump housing..Iaddend.
.Iadd.76. The fluid dispensing pump of claim 67 further comprising
a motor controller that transmits control signals to the
servo-motor to control the rotational position of the feed
screw..Iaddend.
.Iadd.77. The fluid dispensing pump of claim 67 wherein the
servo-motor includes a rotary encoder that generates a feedback
signal related to the rotational position of the feed
screw..Iaddend.
.Iadd.78. The fluid dispensing pump of claim 77 further comprising
a motor controller that transmits control signals to the
servo-motor to control the rotational position of the feed screw in
response to the feedback signal..Iaddend.
.Iadd.79. The fluid dispensing pump of claim 78 wherein the motor
controller transmits control signals to the servo-motor to further
control the rotational velocity of the feed screw..Iaddend.
.Iadd.80. The fluid dispensing pump of claim 78 wherein the motor
controller transmits control signals to the servo-motor to further
control the rotational acceleration of the feed screw..Iaddend.
.Iadd.81. The fluid dispensing pump of claim 67 further comprising
a pump release bracket for releasibly mounting the pump housing to
a pump dispensing frame..Iaddend.
.Iadd.82. A fluid dispensing pump comprising: a cartridge body
having a feed screw cavity and a feed screw mounted in the feed
screw cavity, the cartridge body and the feed screw comprising a
detachable cartridge unit, the feed screw having a helical cavity
defined between a major diameter and a minor diameter of a thread
of the feed screw in which the feed screw is mounted, the cartridge
unit having a feed port in communication with the feed screw for
introduction of dispensing fluids into the helical cavity; a pump
housing including a motor mount and a cartridge cavity, the
cartridge cavity having a mounting location at which the cartridge
unit including both the cartridge body and the feed screw is
inserted into and removed from the cartridge cavity, the pump
housing releasibly securing the cartridge unit in the cartridge
cavity, the cartridge unit having a motor interface at a first end
of the cartridge unit and a fluid outlet at a second end of the
cartridge unit opposite the first end, the cartridge unit including
fluid path between the feed port and the fluid outlet; a
closed-loop servo-motor mounted at the motor mount of the pump
housing, the servo-motor having indexed rotational positions for
controlling rotational position of the feed screw during a
dispensing operation, the servo-motor including a rotary encoder
that generates a feedback signal related to the rotational position
of the feed screw, the motor interface of the cartridge unit being
releasably coupled to the servo-motor when the cartridge unit is
inserted into the cartridge cavity; and a motor controller that
transmits control signals to the servo-motor to control the
rotational position, rotational velocity and rotational
acceleration of the feed screw in response to the feedback signal,
to control a flow of dispensing fluid in the fluid path through the
feed port to the fluid outlet during the dispensing
operation..Iaddend.
.Iadd.83. The fluid dispensing pump of claim 82 wherein the
servo-motor includes a drive axle that is aligned with a neck of
the feed screw..Iaddend.
.Iadd.84. The fluid dispensing pump of claim 82 wherein the motor
mount is positioned at a first end of the pump housing and wherein
the cartridge cavity includes an opening at which the cartridge
unit is inserted into the pump housing at a second end of the pump
housing opposite the first end..Iaddend.
.Iadd.85. The fluid dispensing pump of claim 82 wherein the feed
screw includes a neck..Iaddend.
.Iadd.86. The fluid dispensing pump of claim 82 wherein the neck
extends through a portion of the cartridge body..Iaddend.
.Iadd.87. The fluid dispensing pump of claim 82 wherein the drive
axle is coupled to the feed screw..Iaddend.
.Iadd.88. The fluid dispensing pump of claim 82 further comprising
a transmission coupled between, and aligned with, the drive axle of
the servo-motor and a longitudinal axis of the feed screw for
gearing the feed screw relative to the servo-motor..Iaddend.
.Iadd.89. The fluid dispensing pump of claim 82 further comprising
a notch on an outer surface of the cartridge body adapted to mate
with a pin mounted to the pump housing for securing the cartridge
unit to the pump housing..Iaddend.
.Iadd.90. The fluid dispensing pump of claim 89 wherein the notch
comprises a groove for allowing translation of the cartridge body
relative to the pump housing over the length of the
groove..Iaddend.
.Iadd.91. The fluid dispensing pump of claim 89 wherein the notch
comprises a hole for fixing the longitudinal position of the
cartridge body relative to the pump housing..Iaddend.
.Iadd.92. The fluid dispensing pump of claim 89 further comprising
a cartridge release lever on the pump housing for releasibly
engaging the pin such that the cartridge unit can be released from
the pump housing..Iaddend.
.Iadd.93. The fluid dispensing pump of claim 82 further comprising
a pump release bracket for releasibly mounting the pump housing to
a pump dispensing frame..Iaddend.
.Iadd.94. A fluid dispensing pump comprising: a cartridge body
having a feed screw cavity and a feed screw mounted in the feed
screw cavity, the feed screw having a helical cavity defined
between a major diameter and a minor diameter of a thread of the
feed screw in which the feed screw is mounted, the cartridge body
having a feed port in communication with the feed screw for
introduction of dispensing fluids into the helical cavity and
having an output port at which the dispensing fluids are dispensed
from the helical cavity, the cartridge body including an elongated
notch on an outer surface thereof; a pump housing including a motor
mount and a cartridge cavity, the pump housing releasibly securing
the cartridge body in the cartridge cavity, a cartridge pin coupled
to the pump housing that engages the elongated notch of the
cartridge body, such that when the cartridge is secured in the pump
housing, the elongated notch provides for translation of the
cartridge relative to the pump housing along its length during a
dispensing operation; a closed-loop servo-motor mounted at the
motor mount of the pump housing, the servo-motor having indexed
rotational positions for controlling rotational position of the
feed screw during a dispensing operation, the servo-motor including
a rotary encoder that generates a feedback signal related to the
rotational position of the feed screw; and a motor controller that
transmits control signals to the servo-motor to control the
rotational position, rotational velocity, and rotational
acceleration of the feed screw in response to the feedback
signal..Iaddend.
.Iadd.95. The fluid dispensing pump of claim 94 wherein the
cartridge pin secures the cartridge in the pump housing and seats
in the elongated notch to restrict an extent of translation of the
cartridge in the pump housing..Iaddend.
.Iadd.96. The fluid dispensing pump of claim 94 wherein the
cartridge pin is activated by a cartridge release
lever..Iaddend.
.Iadd.97. The fluid dispensing pump of claim 96 wherein the
cartridge release lever pivots relative to the cartridge
housing..Iaddend.
.Iadd.98. The fluid dispensing pump of claim 94 wherein the
servo-motor includes a drive axle that is aligned with a neck of
the feed screw..Iaddend.
.Iadd.99. The fluid dispensing pump of claim 94 wherein the motor
mount is positioned at a first end of the pump housing and wherein
the cartridge cavity includes an opening at which the cartridge is
inserted into the pump housing at a second end of the pump housing
opposite the first end..Iaddend.
.Iadd.100. The fluid dispensing pump of claim 94 wherein the feed
screw includes a neck..Iaddend.
.Iadd.101. The fluid dispensing pump of claim 100 wherein the neck
extends through a portion of the cartridge body..Iaddend.
.Iadd.102. The fluid dispensing pump of claim 94 wherein the drive
axle is coupled to the feed screw..Iaddend.
.Iadd.103. The fluid dispensing pump of claim 94 further comprising
a transmission coupled between, and aligned with, the drive axle of
the servo-motor and a longitudinal axis of the feed screw for
gearing the feed screw relative to the servo-motor..Iaddend.
.Iadd.104. The fluid dispensing pump of claim 94 further comprising
a pump release bracket for releasibly mounting the pump housing to
a pump dispensing frame..Iaddend.
.Iadd.105. A fluid dispensing pump comprising: a feed screw having
a helical cavity defined between a major diameter and a minor
diameter of a thread of the feed screw; a cartridge body having a
feed cavity in communication with the feed screw for introduction
of dispensing fluids into the helical cavity, the cartridge body
having a notch on an outer surface adapted to mate with a pin
mounted to a pump body for securing the cartridge body to the pump
body, wherein the notch comprises a groove for allowing translation
of the cartridge body relative to the pump body over the length of
the groove; and a closed-loop servo-motor having indexed rotational
positions for controlling rotational position of the feed screw
during a dispensing operation, the servo-motor including a rotary
encoder that generates a feedback signal related to the rotational
position of the feed screw..Iaddend.
.Iadd.106. A fluid dispensing pump comprising: a feed screw having
a helical cavity defined between a major diameter and a minor
diameter of a thread of the feed screw; a cartridge body having a
feed cavity in communication with the feed screw for introduction
of dispensing fluids into the helical cavity, the cartridge body
having a notch on an outer surface adapted to mate with a pin
mounted to a pump body for securing the cartridge body to the pump
body; a cartridge release lever for releasibly engaging the pin
such that the cartridge body can be released from the pump body;
and a closed-loop servo-motor having indexed rotational positions
for controlling rotational position of the feed screw during a
dispensing operation, the servo-motor including a rotary encoder
that generates a feedback signal related to the rotational position
of the feed screw..Iaddend.
.Iadd.107. A fluid dispensing pump comprising: a cartridge body
having a feed screw cavity and a feed screw mounted in the feed
screw cavity, the feed screw having a helical cavity defined
between a major diameter and a minor diameter of a thread of the
feed screw in which the feed screw is mounted, the cartridge body
having a feed port in communication with the feed screw for
introduction of dispensing fluids into the helical cavity; a pump
housing including a motor mount and a cartridge cavity, the pump
housing releasibly securing the cartridge body in the cartridge
cavity; a pump release bracket for releasibly mounting the pump
housing to a pump dispensing frame; a closed-loop servo-motor
mounted at the motor mount of the pump housing, the servo-motor
having indexed rotational positions for controlling rotational
position of the feed screw during a dispensing operation, the
servo-motor including a rotary encoder that generates a feedback
signal related to the rotational position of the feed screw; and a
motor controller that transmits control signals to the servo-motor
to control the rotational position, rotational velocity and
rotational acceleration of the feed screw in response to the
feedback signal..Iaddend.
Description
BACKGROUND OF THE INVENTION
Contemporary fluid dispense systems are well suited for dispensing
precise amounts of fluid at precise positions on a substrate. A
pump transports the fluid to a dispense tip, also referred to as a
"pin" or "needle", which is positioned over the substrate by a
micropositioner, thereby providing patterns of fluid on the
substrate as needed. As an example application, fluid delivery
systems can be utilized for depositing precise volumes of
adhesives, for example, glue, resin, or paste, during a circuit
board assembly process, in the form of dots for high-speed
applications, or in the form of lines for providing underfill or
encapsulation.
Contemporary dispensing pumps comprise a syringe, a feed tube, a
dispense cartridge, and pump drive mechanism. The syringe contains
fluid for dispensing, and has an opening at its distal end at which
a feed tube is connected. The feed tube is a flexible, hollow tube
for delivering the fluid to the cartridge. The cartridge is hollow
and cylindrical and includes an inlet neck at which the opposite
end of the feed tube is connected. The inlet neck directs the fluid
into the hollow, central cartridge chamber.
A feed screw disposed longitudinally through the center of the
cylindrical chamber transports the fluid in Archimedes principle
fashion from the inlet to a dispensing needle attached to the
chamber outlet. A continuously-running motor drives the feed screw
via a rotary clutch, which is selectively actuated to engage the
feed screw and thereby effect dispensing. A bellows linkage between
the motor and cartridge allows for flexibility in system
alignment.
Pump systems can be characterized generally as "fixed-z" or
"floating-z" (floating-z is also referred to as "compliant-z").
Fixed-z systems are adapted for applications that do not require
contact between the dispense tip and the substrate during
dispensing. In fixed-z applications, the dispense tip is positioned
and suspended above the substrate by a predetermined distance, and
the fluid is dropped onto the substrate from above. In floating-z
applications, the tip is provided with a standoff, or "foot",
designed to contact the substrate as fluid is delivered by the pump
through the tip. Such floating-z systems allow for tip travel,
relative to the pump body, such that the entire weight of the pump
does not bear down on the substrate.
Such conventional pump systems suffer from several limitations. The
motor and rotary clutch mechanisms are bulky and heavy, and are
therefore limited in application for modern dispensing applications
requiring increasingly precise, efficient, and fast operation. The
excessive weight limits use for those applications that require
contact of the pump with the substrate, and limits system speed and
accuracy, attributed to the high g-forces required for quick
movement of the system. The mechanical clutch is difficult to
control, and coasts to a stop when disengaged, resulting in deposit
of excess fluid. Clutch coasting can be mitigated by a longitudinal
spring mounted about the body of the feed screw and urged against
the chamber end to offer rotational resistance. However, the spring
adds to the length of the cartridge, and contributes to system
complexity.
The inlet neck feeds directly into the side of the feed screw or
"auger". Consequently, as the auger collects material from the
small and circular inlet port, high pressure is required for
driving the material into the auger body, because the auger threads
periodically pass in front of the feed opening, preventing material
from entering. This leads to inconsistent material flow.
Additionally, the inlet neck is commonly perpendicular to the auger
screw, requiring the fluid to make a 90 degree turn upon entering
the pump. This further limits material flow and can contribute to
material "balling" and clogging.
Overnight storage of dispensed fluids often requires refrigeration
of the fluid and cleaning of the system. The syringe is typically
mounted directly to a mounting bracket on the pump body such that
the output port of the syringe passes through a aperture on the
mounting bracket. The feed tube is then coupled to the output port
on the opposite face of the bracket. Since the tube and bracket are
on opposite sides of the bracket, removal of the syringe from the
pump body requires dismantling of the tube and syringe, which can
contaminate fluid material positioned at the interface during
disassembly. Further, since the syringe and cartridge can not be
removed and stored together as a unit, disassembly and cleaning of
the cartridge is required. Additionally, the inlet neck is narrow
and therefore difficult to clean.
SUMMARY OF THE INVENTION
The present invention is directed to a fluid group and cartridge
system that overcomes the limitations of conventional systems set
forth above.
In a first aspect, the present invention is directed to a cartridge
adapted for use with a fluid pump. The cartridge includes a
material inlet port, a material outlet port, a feed screw, and a
reservoir. The feed screw is disposed longitudinally through the
body of the cartridge for delivering fluid provided at the inlet
port to the outlet port. The inlet port takes the form of an
elongated port provided at a side portion of the feed screw
proximal to allow for fluid provided at the inlet port. This
elongated configuration promotes even distribution of fluid during
transport by the feed screw, and lowers system pressure, thereby
reducing the likelihood of "balling-up" and/or clogging of
fluid.
The inlet port is preferably provided through the cartridge body at
an acute angle relative to the reservoir to allow for
gravity-assisted fluid delivery. The inner portion of the cartridge
may be lined with a carbide or plastic (for example Teflon, torlon,
or tercite) liner having an aperture aligned with the inlet port to
enhance ease of cleaning. The elongated port of the cartridge may
be provided in a wall of the carbide liner.
In another aspect, the present invention is directed to a release
bracket for mounting the syringe and cartridge to the body of the
pump. In this manner, the syringe, feed tube, and cartridge can be
dismantled from the pump body as a unit, allowing for joint storage
of the syringe, feed tube and cartridge, while minimizing risk of
contamination of the material. Additionally, once the system is
initially purged of extraneous gas during initialization, the
purged system can be stored as a unit without the need for
re-initialization prior to its next use.
In another aspect, the present invention is directed to a fluid
pump assembly that employs an electronically-operated servo-motor
assembly. A closed-loop servo motor having a rotary encoder is
adapted for controlling rotation and position of the feed screw
with heightened accuracy, as compared to those of conventional
clutch-driven assemblies. For example, in a preferred embodiment, a
rotary encoder capable of 8000 counts in a 360 degree range may be
employed to achieve dispensing resolution to a degree that is
orders of magnitude greater than conventional systems.
Servo-motor-based systems further confer the advantages of small,
lightweight systems well-suited for high-performance operation.
Electronic control allows for complete determination of the
acceleration/deceleration of feed screw rotation, allowing for
application-specific flow profiles. An orbital gear transmission
unit may be provided between the motor and the pump feed screw for
providing further accuracy in controlling the feed screw.
In another aspect, the present invention is directed to a pump
assembly that is compatible with both floating-z and fixed-z
cartridges and dispensing tips. A quick-release pin, which may be
spring-biased, is provided on the side of the cartridge body to
allow for removal/insertion of cartridges. A fixed-z cartridge
includes a hole for receiving the quick-release pin in a fixed
relationship. A floating-z cartridge includes a longitudinal groove
to permit longitudinal travel of the pin in the groove, and thus
allow for floating-z operation.
In another aspect, the present invention is directed to a
quick-release mount assembly for mounting a pump to a dispensing
frame. The pump body includes a tab feature on its surface for
mating with a hole on a mounting plate attached to the dispensing
frame. The mounting plate includes a lever for securing the tab
when inserted. Guide features may be provided for aligning and
guiding the pump body relative to the mounting plate.
In another aspect, the present invention is directed to an
apparatus and method for drawing entrapped air from the material
supply during a dispensing operation, thereby purging the system of
entrapped air. A vacuum is drawn from the material supply, for
example by a vacuum tube with needle inserted into a material feed
tube, in a direction parallel to material flow through the feed
tube. In this manner, air is withdrawn from the dispensed material,
leading to an improvement in dispensing consistency, especially at
small tolerances.
In another aspect, the present invention is directed to a vacuum
purge configuration for removing air entrapped in the body of the
cartridge during initialization of a dispensing operation. A first
purge interface is placed on the end of the feed tube, and a vacuum
is drawn, thereby purging the feed tube of entrapped gas. A second
purge interface is then placed on the cartridge body outlet while
the feed screw is rotated slowly until material presents itself at
the outlet. A vacuum is drawn to eliminate entrapped gas from the
cartridge. A third purge interface is then placed on the needle
assembly and a vacuum is drawn to eliminate entrapped air from the
needle body. Entrapped air is thus substantially removed from the
feed tube, auger screw and dispensing needle. Normal dispensing can
commence following removal of the purge interface.
In another aspect, the present invention is directed to a bellows
means inserted at the piston end of, and replacing the piston of, a
dispensing syringe. The bellows is pressurized from within and
expands, thereby exerting pressure on the underlying material,
forcing material flow. In this manner, material can be driven with
minimal pressure, and with minimal air migration into the material,
as compared to plunger-style drivers. In a preferred embodiment,
the bellows comprises a latex film applied about the lip of the
syringe top. The syringe top is preferably vented to allow for
expansion of the bellows.
In another aspect, the present invention is directed to a pump
cartridge having a material feed aperture that is elongated with
respect to the primary axis of the feed screw. In this manner, a
larger portion of the feed screw threads are exposed to the
material supply, leading to improvement in dispensing consistency.
In a preferred embodiment, a carbide cartridge liner is inserted in
the cartridge cavity between the cartridge body and the feed screw,
and the elongated aperture is provided in the body of the carbide
insert to provide increased material supply exposure.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the
invention will be apparent from the more particular description of
preferred embodiments of the invention, as illustrated in the
accompanying drawings in which like reference characters refer to
the same parts throughout the different views. The drawings are not
necessarily to scale, emphasis instead being placed upon
illustrating the principles of the invention.
FIGS. 1A and 1B are an exploded perspective view and an assembled
perspective view respectively of a pump assembly configured in
accordance with the present invention.
FIGS. 2A and 2B are an exploded perspective view and an assembled
perspective view respectively of a fixed-z-type cartridge assembly
in accordance with the present invention.
FIGS. 3A and 3B are an exploded perspective view and an assembled
perspective view respectively of a floating-z-type cartridge
assembly in accordance with the present invention
FIGS. 4A, 4B and 4C are side views of a cartridge opening
illustrating the conventional embodiment having a small, circular
opening, and first and second embodiments of the present invention
having elongated openings respectively.
FIG. 5A is a cutaway side view of a cartridge feed mechanism
employing a carbide liner including an elongated slot at the inlet
to allow for increased capturing of input material at the feed
screw inlet, in order to promote consistency in material flow at a
reduced pressure, in accordance with the present invention.
FIG. 5B is a perspective view of the liner having an elongated
slot, in accordance with the present invention.
FIGS. 6A and 6B illustrate operation of the syringe and cartridge
quick release mechanisms, in accordance with the present
invention.
FIGS. 7A and 7B illustrate a side view and front view respectively
of a quick-release mounting plate, for mounting the pump to a pump
dispensing frame, in accordance with the present invention.
FIG. 8 is a illustration of an improved dispensing configuration
employing a vacuum tube inserted into the material feed tube, in
accordance with the present invention.
FIG. 9 is an illustration of an air purge configuration wherein a
purge vacuum is applied to the needle assembly for initially
purging the material flow of air pockets, to prime the system for
dispensing, in accordance with the present invention.
FIG. 10 is an illustration of a bellows configuration for
application to the top of a material feed syringe, allowing for use
of minimal pressure to drive material flow with mitigation or
elimination of air migration into the material, in accordance with
the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 1A and 1B are an exploded perspective view and an assembled
perspective view respectively of a pump assembly configured in
accordance with the present invention. With reference to FIGS. 1A
and 1B, an embodiment of the dispensing pump 18 comprises a motor
42, an optional transmission box 44, a pump housing 52, and a
cartridge 58.
The motor 42 preferably comprises a closed-loop servo motor with an
independent motion controller 43. The motion controller 43 may be
provided by the host dispensing platform, and may comprise, for
example, a Delta Tau controller, Northbridge, Calif., USA. The
closed-loop servo motor may comprise, for example, a Sigma Mini
Series motor, produced by Yaskawa Electric Corp., Japan. Feedback
is preferably provided by a rotary encoder, for example providing
8192 discrete counts over 360 degree rotation. The motor 42
includes an axle 41 which operates to drive the feed screw in the
cartridge assembly 58 (described below). In this manner,
high-performance control is maintained over material dispensing.
For example, rotary position, rotational velocity, and
acceleration/deceleration of the feed screw can be readily
controlled by the closed-loop servo motor, and is easily programmed
at the controller 43. This is compared to conventional embodiments
that rely on timed open-loop coasting of a mechanical clutch for
control over the feed screw. Additionally, the closed-loop
servo-motor is generally a compact system that is small,
lightweight, and designed for high-performance operation; as
compared to the bulky, inefficient, and inaccurate conventional
motor pump systems.
An optional planetary-gear transmission box 44 may be provided to
step down the available motor positions, thereby providing even
more enhanced control over angular position of the feed screw. For
example, step-down transmissions offering 7:1, 25:1, and 48:1
step-down ratios are available for increasing the number of angular
steps from 8,192 to 57,344, 204,800 and 393,216 respectively,
depending on the application. Such transmission boxes are also
available in compact units that match well in size and weight with
the closed-loop servo motor 42.
The pump housing 52 comprises a machined or die cast body having an
opening 49 at a top portion for receiving the motor drive axle 41
or optional transmission box 44 drive axle (not shown). The
interior of the housing 52 is hollow for receiving a cartridge 58
that extends through the housing 52 from an opening 51 at a bottom
portion, upward to the top portion, and interfaces with the motor
drive axle or transmission box drive axle. The motor 42 and
transmission box 44 are mounted to each other, and to the housing
52, by bolts 46, and screws 24, 28, and 30. Cavities 53 are
preferably provided in the walls of the housing 52, in order to
reduce weight.
A cartridge release lever 34 is rotatably mounted to the housing 52
by bolt 38. When rotated, the cartridge release lever 34 engages an
actuator pin 56, biased by spring 54 to remain in a released
position. With reference to FIGS. 6A and 6B, the actuator pin 56
extends into the body of the housing 52 and engages an actuator pin
capture 62 (see FIG. 2B) or elongated actuator pin capture (see
FIG. 3B) formed in the cartridge body 60. In this manner the
cartridge release lever is operable to remove/insert a cartridge 58
at the underside of the housing 52 as indicated by arrow 95 (see
FIG. 1B).
A syringe 22 and feed tube 40 are releasibly coupled to a side wall
of the housing, as shown. The syringe 22 includes a syringe holder
20, a syringe body 22, and a syringe outlet 32. The feed tube 40 is
preferably formed of a flexible material, a first end of which
elastically deforms to fit over the end of the syringe outlet 32 to
form a tight seal. The second end of the feed tube 40 inserts into
a feed aperture 64 (see FIGS. 2B and 3B) formed in the cartridge
body 60.
With reference again to FIGS. 6A and 6B, the syringe 22 is likewise
preferably configured to be readily separable from the pump housing
52, along with the cartridge 58. To accommodate this feature, a
syringe quick-release arm 48 extends from a side wall of the pump
housing 52, and includes a slot for map-capturing a neck portion 33
of the syringe outlet. The quick release arm preferably elastically
deforms to receive the neck 33, and to fix the syringe 22 in
position during a dispensing operation. In this manner, the
cartridge release lever 34 operates in conjunction with the syringe
quick release arm to allow for easy removal and storage of the
cartridge mechanism 58 and syringe 22 as a unit. This is especially
helpful in situations where overnight refrigeration of the
dispensing material is required, since the entire material pathway
can be removed and stored as a unit, without the need for
disassembly and cleaning of the individual components, as required
by conventional pump configurations.
A release bracket 50 is mounted to a side wall of the housing 52 by
bolts 36. With reference to FIGS. 7A and 7B, the release bracket 50
includes first and second alignment pins 110 and a central lock pin
114, including a body 11 and retaining head 112, extending
outwardly from its surface. A corresponding release bracket plate
124 is mounted to a dispensing frame 122, and includes alignment
pin captures 116, a lock pin capture 118 and a spring-loaded lever
120. When operated, the lever, engages/disengages a clasp within
the lock pin capture 118, that, in turn, clasps the retaining head
112 of the release bracket, when inserted and properly aligned with
the plate 124. In this manner, the pump 18 can be readily
attached/detached from the pump dispensing frame for maintenance
and inspection.
FIGS. 2A and 2B are an exploded perspective view and an assembled
perspective view respectively of a fixed-z-type cartridge 58
assembly in accordance with the present invention. The cartridge
assembly includes an elongated cartridge body 60, a first end of
which is adapted to receive a fixed-z-type dispensing needle, for
example Laser.TM.-style needle 68. An opening at a second end of
the cartridge receives an auger screw, or feed screw 74 having
threads 75 at a first end, and having an indexed shaft 66 at an
opposite end, adapted to register with the motor axle 41, or
transmission axle. The auger screw 74 includes a collar 78, the
height of which is adjustable by set screw 76. Washer 72 ensures a
tight seal. A cap nut 80 contains the various cartridge components
within the cartridge body 60. As explained above, an inlet port 64
is formed in the body 60 of the cartridge for receiving an end of
the feed tube, for the delivery of material toward the feed screw
threads 75. An actuator pin capture 62 engages the cartridge
release pin 56, as described above. In the fixed-z embodiment of
FIGS. 2A and 2B, the actuator pin capture 62 is the size of the
release pin, to prevent longitudinal travel of the pump.
FIGS. 3A and 3B are an exploded perspective view and an assembled
perspective view respectively of a floating-z-type cartridge 58
assembly in accordance with the present invention. In this
embodiment, the feed screw mechanism is similar to that of FIGS. 2A
and 2B; however, the cartridge is adapted for receiving a
floating-z-type dispensing needle 82. The needle body 82 registers
with locator 88 at the cartridge outlet, and is fixed in place by
needle nut 84. For the floating-z-type cartridge assembly, an
elongated actuator pin capture 86 is provided to allow for
longitudinal travel of the cartridge 58 relative to the pump
housing 52 during a dispensing operation.
FIGS. 4A of a inlet port for a conventional cartridge 108
embodiment having a small, circular port opening 106. In this
embodiment, it can be seen that the pressurized material entering
the port opening 106 periodically confronts a major diameter of the
feed screw thread 102, which periodically inhibits flow of material
into the feed screw cavity formed between the minor diameter
portion 104 of the thread and the interior wall of the cartridge
body 108. As much as 1/3 to 1/2 of the port opening can be
periodically blocked by the major diameter of the feed screw thread
102 at any given time. The blockage fluctuates as a function of the
rotational position of the feed screw which can cause inconsistency
in material dispensing, especially at small tolerances. The
blockage further increases the likelihood of material stagnation
and drying at the inlet port, in turn causing system
contamination.
The present invention overcomes this limitation by providing an
elongated cartridge inlet port. With reference to FIGS. 4B and 4C,
the elongated inlet port 100 of the present invention is preferably
elongated in a longitudinal direction, with respect to the
longitudinal axis of the feed screw 74. In this manner, dispensing
material is presented to a larger portion of the feed screw cavity
formed between the minor diameter portion 104 and the inner wall of
the cartridge 70. This configuration reduces pressure requirements
for material delivery through the system, and enhances consistency
in material flow, as the dependency on material flow rate as a
function of the feed screw thread position is mitigated or
eliminated. In general, a longer inlet port as shown in FIG. 3 is
preferred, as compared to the relatively shorter inlet port 100
shown in FIG. 4B; however, the inlet port 100 should not be so long
as to provide an opportunity for pooling of dormant material in the
inlet port 100 prior to flow through the feed screw 74.
FIG. 5A is a cutaway side view of a cartridge feed mechanism
employing a carbide liner 70 including an elongated slot 100 at the
inlet port to allow for increased capturing of input material at
the feed screw inlet, in order to promote consistency in material
flow at a reduced pressure, in accordance with the present
invention. FIG. 5B is a perspective view of the liner having an
elongated slot, in accordance with the present invention.
In this embodiment, the elongated inlet port is provided by a slot
100 formed in a side wall of a cylindrical carbide liner 70
inserted in the cartridge body 60 about the feed screw 74. The
cartridge inlet port 64 comprises a standard circular bore formed
in the cartridge body 60, preferably at an acute angle relative to
the feed screw 74, to allow gravity to assist in material flow. An
elongated chamber, or pocket 101, is formed within the slot 100,
between the feed screw 74 and the inner wall 103 of the cartridge
body, in a region proximal to the inlet port 64. The elongated
pocket 101 allows for dispensing fluid to migrate in a downward
direction, and is captured by the feed screw threads over a larger
surface area, conferring the various advantages outlined above.
FIG. 8 is a illustration of an improved dispensing configuration
employing a vacuum tube inserted into the material feed tube. In
this embodiment, entrapped gas impurities, such as air
microbubbles, are drawn from the material supply during a
dispensing operation, thereby purging the system of entrapped air.
A vacuum unit 126 draws a vacuum from the material supply tube 40,
for example by a vacuum tube 127 with needle 128 inserted into the
material feed tube 40, along the direction of material flow, as
shown. In this manner, air is withdrawn from the dispensed
material, leading to an improvement in dispensing consistency,
especially at small tolerances.
FIG. 9 is an illustration of an air purge configuration wherein a
purge vacuum is applied to the needle assembly for initially
purging the material flow of air pockets, to prime the system for
dispensing. In this process a first purge interface 134 is placed
on the end of the feed tube, and a vacuum is drawn by vacuum unit
126, thereby purging the feed tube 40 of entrapped gas. A second
purge interface 134 is then placed on the cartridge body outlet 133
while the feed screw is rotated slowly until material presents
itself at the outlet 133. A vacuum is drawn by vacuum unit 126 to
eliminate entrapped gas from the cartridge. A third purge interface
134 is then placed on the needle assembly 82 and a vacuum is drawn
by vacuum unit 126 to eliminate entrapped air from the needle body.
Entrapped air is thus substantially removed from the feed tube,
auger screw and dispensing needle. Normal dispensing can commence
following removal of the purge interface. Note that the first,
second and third purge interfaces 126 may require different
interface configurations for the different components undergoing
purging.
FIG. 10 is an illustration of a bellows configuration for
application to the top of a material feed syringe, allowing for use
of minimal pressure to drive material flow with mitigation or
elimination of air migration into the material. In this
configuration, a bellows means 130, for example comprising an
air-tight, flexible material, is inserted at the piston end of, and
replaces the piston of, a dispensing syringe 22. The bellows is
pressurized by air pressure unit 132 from within and expands,
thereby exerting pressure on the underlying material 135, forcing
material flow through the outlet 32. In this manner, material can
be driven with minimal pressure, and with minimal air migration
into the material, as compared to plunger-style drivers. In a
preferred embodiment, the bellows comprises a latex film applied
about the lip of the syringe top. The flexible latex film serves to
conform to the inner walls of the syringe during expansion, pushing
the underlying material in a downward direction The syringe top is
preferably vented to allow for expansion of the bellows.
In this manner a high-performance, lightweight pump configuration
is provided. The pump is operable in both fixed-z and floating-z
mode. Quick release mechanisms provide for storage of the syringe
and cartridge as a single unit, without the need for component
disassembly. The components themselves are relatively easy to clean
and maintain. The elongated inlet port provides for enhanced
dispensing consistency at a lower material pressure, while the
various purging and priming techniques allow for removal of
entrapped gases, further improving dispensing consistency.
While this invention has been particularly shown and described with
reference to preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and detail
may be made herein without departing from the spirit and scope of
the invention as defined by the appended claims.
For example, the enhanced control over material flow offered by the
various configurations of the present invention make the pump
system of the present invention especially amenable to use with
dispense needles having a flat dispensing surface with a cross
pattern formed in the dispensing surface for dispensing .Iadd.a
.Iaddend.cross .[.patterns.]. .Iadd.pattern .Iaddend.for providing
a .[.fillets.]. .Iadd.fillet .Iaddend.for .[.boding.].
.Iadd.bonding .Iaddend.a .[.dye.]. .Iadd.die .Iaddend.to a
substrate. Particularly, since the closed-loop servo motor pump of
the present invention offers control over both position and
velocity of the feed screw, the delivery of fluid through the
needle to the cross pattern can be controlled to a level of
precision previously unattainable. Cross-pattern-style fillets can
be achieved at a level of accuracy orders of magnitude beyond those
currently achieved.
* * * * *