U.S. patent application number 10/696984 was filed with the patent office on 2005-05-05 for door locking mechanism.
This patent application is currently assigned to DEKA Products Limited Partnership. Invention is credited to Dale, James D..
Application Number | 20050095152 10/696984 |
Document ID | / |
Family ID | 34557940 |
Filed Date | 2005-05-05 |
United States Patent
Application |
20050095152 |
Kind Code |
A1 |
Dale, James D. |
May 5, 2005 |
Door locking mechanism
Abstract
A system and method for locking a door. An assembly has a first
engagement surface. A door is coupled to the assembly, the door
including a latch member having a second engagement surface for
engaging the first engagement surface. A movable member is capable
of generating a force against at least one of the assembly and the
door to press together and substantially prevent disengagement of
the first engagement surface and the second engagement surface.
Inventors: |
Dale, James D.; (Nashua,
NH) |
Correspondence
Address: |
BROMBERG & SUNSTEIN LLP
125 SUMMER STREET
BOSTON
MA
02110-1618
US
|
Assignee: |
DEKA Products Limited
Partnership
Manchester
NH
|
Family ID: |
34557940 |
Appl. No.: |
10/696984 |
Filed: |
October 30, 2003 |
Current U.S.
Class: |
417/477.2 ;
417/572 |
Current CPC
Class: |
F04B 43/06 20130101;
B01F 15/0475 20130101; B01F 13/1016 20130101; B01F 2015/0221
20130101; F04B 43/0009 20130101; A61M 1/3687 20130101; F04B 49/22
20130101; Y10T 137/86131 20150401; Y10T 137/0352 20150401; Y10T
29/53 20150115; Y10T 137/0329 20150401; B01F 15/0202 20130101; F04B
53/16 20130101; B01F 13/1013 20130101; Y10T 292/0911 20150401; Y10T
292/438 20150401; B01F 3/0865 20130101; B01F 5/0077 20130101; A61L
2/0088 20130101; A61M 1/0213 20140204; A61M 1/0281 20130101; Y10T
292/212 20150401; Y10T 137/87652 20150401; A61M 2205/125 20130101;
F04B 53/22 20130101; B01F 5/12 20130101; A61L 2/24 20130101; A61M
1/0272 20130101; G05D 11/132 20130101; B01F 3/088 20130101 |
Class at
Publication: |
417/477.2 ;
417/572 |
International
Class: |
F04B 043/08; F04B
045/06; F04B 043/12 |
Claims
What is claimed is:
1. A door locking system comprising: an assembly including a
latching structure having a first engagement surface and a first
overlap surface; a door movably coupled to the assembly, the door
including a latch member having a second engagement surface and a
second overlap surface, the door having a closed position in which
the first engagement surface at least partially contacts the second
engagement surface and the first overlap surface at least partially
overlaps the second overlap surface, the second engagement surface
required to move beyond the first engagement surface in order to
close and open the door; and a movable member capable of generating
a force against at least one of the assembly and the door to press
together and substantially prevent disengagement of the first
engagement surface and the second engagement surface.
2. The door locking system according to claim 1, wherein the first
engagement surface forms an undercut.
3. The door locking system according to claim 2, wherein the second
engagement surface forms a projection for engaging the
undercut.
4. The door locking system according to claim 1, wherein the latch
member includes a post extending from the door, the post including
the second engagement surface.
5. The door locking system according to claim 1, wherein the latch
member includes a handle for operating the latch, the handle
capable of pivoting to control alignment of the second engagement
surface.
6. The door locking system according to claim 5, wherein the handle
is substantially incapable of pivoting when the first engagement
surface is engaged with the second engagement surface and the
movable member is generating force against one of the door and the
assembly.
7. The door locking system according to claim 1, wherein the
movable member is capable of generating a continuous force against
the at least one of the assembly and the door.
8. The door locking system according to claim 1, wherein the
movable member is coupled to one of the door and the assembly.
9. The door locking system according to claim 1, wherein the
movable member is positioned between the door and a surface of the
assembly.
10. The door locking system according to claim 1, wherein the
movable member is an expandable member.
11. The door locking system according to claim 10, wherein the
expandable member is a bladder.
12. The door locking system according to claim 1, further including
a pneumatic circuit for controlling the movable member.
13. The door locking system according to claim 1, wherein the
assembly includes a control element for operating a pump
cassette.
14. The door locking system according to claim 13, wherein the
control element includes: a bezel; and a bezel gasket including a
membrane capable of being displaced so as to operate the pump
cassette.
15. The door locking system according to claim 14, further
including a pneumatic control circuit for displacing the
membrane.
16. The door locking system according to claim 13, further
including a cassette receptacle movably coupled to one of the door
and the assembly, the cassette receptacle capable of receiving the
pump cassette.
17. The door locking system according to claim 16, wherein the
movable member is capable of pressing the cassette against the
control element.
18. The door locking system according to claim 1, wherein the
movable member contacts the at least one of the assembly and the
door.
19. The door locking system according to claim 1, further
comprising an element positioned between the movable member and the
at least one of the assembly and the door, wherein the movable
member contacts the element when generating the force.
20. The door locking system according to claim 19, wherein the
element is a pump cassette.
21. A door locking system comprising: an assembly having a first
engagement means; a door coupled to the assembly, the door
including a second engagement means for engaging the first
engagement means; and movable means for generating a force against
at least one of the assembly and the door to press together and
substantially prevent disengagement of the first engagement surface
and the second engagement surface.
22. The door locking system according to claim 21, wherein the
first engagement means includes a surface forming an undercut, and
the second engagement means forms a projection for engaging the
undercut.
23. The door locking system according to claim 21, further
including a handle attached to the second engagement means.
24. The door locking system according to claim 21, wherein the
movable means includes an expandable member.
25. The door locking system according to claim 24, wherein the
expandable member is a bladder.
26. The door locking mechanism according to claim 21, further
including a pneumatic circuit for controlling the moving
member.
27. The door locking system according to claim 21, wherein the
assembly includes control means for operating a pump cassette.
28. The door locking system according to claim 27, wherein the
control means includes: a bezel; and a bezel gasket including a
membrane capable of being displaced so as to operate the pump
cassette.
29. The door locking system according to claim 28, further
including a pneumatic control circuit for displacing the
membrane.
30. The door locking system according to claim 18, where the
movable means is positioned between the door and the assembly.
31. The door locking system according to claim 21, wherein the
movable means is capable of contacting and pressing against the at
least one of the assembly and the door.
32. The door locking system according to claim 21, further
comprising an element positioned between the movable means and the
at least one of the assembly and the door, wherein the movable
member contacts the element when generating the force.
33. The door locking system according to claim 32, wherein the
element is a pump cassette.
34. A door locking method comprising: providing an assembly
including a latching structure having a first engagement surface
and a first overlap surface, the assembly coupled to a door, the
door including a latch member having a second engagement surface
and a second overlap surface, the door having a closed position in
which the first engagement surface at least partially contacts the
second engagement surface and the first overlap surface at least
partially overlaps the second overlap surface, the second
engagement surface required to move beyond the first engagement
surface in order to close and open the door; and moving a movable
member to generate a force against at least one of the door and the
assembly to press together and substantially prevent disengagement
of the first engagement surface and the second engagement
surface.
35. The door locking method according to claim 34, wherein the
first engagement surface forms an undercut and the second
engagement surface forms a projection for engaging the
undercut.
36. The door locking method according to claim 34, further
comprising controlling a handle to operate the latch member.
37. The door locking method according to claim 36, wherein prior to
moving the movable member the method further comprising: closing
the door; and moving the handle such that the second engagement
surface of the latch member is aligned to engage the first engaging
surface.
38. The door locking method according to claim 36, further
comprising: moving the movable member away from the one of the door
and the assembly; moving the handle such that the second engagement
surface is in non-alignment to engage the first engaging surface;
and opening the door.
39. The door locking method according to claim 34, wherein moving
the movable member against one of the assembly and the door
includes expanding an expandable member.
40. The door locking method according to claim 39 wherein the
expandable member is a bladder, and expanding the expandable member
includes pneumatically operating the bladder.
41. The door locking method according to claim 34, wherein a
cassette receptacle is attached to one of the door and the
assembly, the method further comprising: inserting a pump cassette
into the cassette receptacle.
42. The door locking method according to claim 41, wherein the
assembly includes a membrane capable of being displaced, the method
further comprising pneumatically displacing the membrane to operate
the pump cassette.
43. The door locking method according to claim 41, wherein moving
the movable member includes moving the movable member against one
of the pump cassette and the cassette receptacle to press the pump
cassette against the membrane.
44. The door locking method according to claim 34, wherein moving
the movable member includes placing the movable member in contact
with the at least one of the assembly and the door.
45. The door locking method according to claim 34, wherein moving
the movable member includes placing the movable member in contact
with an element positioned between the at least one of the assembly
and the door, such that a force is generated on the at least one of
the assembly and the door.
46. The door locking method according to claim 45, wherein the
element is a pump cassette.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application may include subject matter related
to one or more of the following commonly-owned United States patent
applications, each of which was filed on even date herewith and is
hereby incorporated herein by reference in its entirety:
[0002] U.S. patent application Ser. No. ______ entitled SYSTEM,
DEVICE, AND METHOD FOR MIXING A SUBSTANCE WITH A LIQUID (referred
to herein as "Application D70");
[0003] U.S. patent application Ser. No. ______ entitled SYSTEM,
DEVICE, AND METHOD FOR MIXING LIQUIDS (referred to herein as
"Application D71");
[0004] U.S. patent application Ser. No. ______ entitled TWO-STAGE
MIXING SYSTEM, APPARATUS, AND METHOD (referred to herein as
"Application D72");
[0005] U.S. patent application Ser. No. ______ entitled SYSTEM AND
METHOD FOR PUMPING FLUID USING A PUMP CASSETTE (referred to herein
as "Application D73");
[0006] U.S. patent application Ser. No. ______ entitled BEZEL
ASSEMBLY FOR PNEUMATIC CONTROL (referred to herein as "Application
D75");
[0007] U.S. patent application Ser. No. ______ entitled PUMP
CASSETTE WITH SPIKING ASSEMBLY (referred to herein as "Application
D84"); and
[0008] U.S. patent application Ser. No. ______ entitled PUMP
CASSETTE BANK (referred to herein as "Application D85").
FIELD OF THE INVENTION
[0009] The present invention relates generally to a door locking
mechanism.
BACKGROUND OF THE INVENTION
[0010] Various door latch mechanisms for fastening a door to an
assembly are known in the prior art. For example, a spring-loaded
latch may protrude through the door and include a projection for
engaging an undercut on the assembly. Upon pushing the door closed,
the projection on the latch aligns with the undercut to prevent the
door from being opened. Opening the door includes manipulating the
handle such that the projection and undercut are no longer aligned,
and then pulling on the door.
[0011] One disadvantage of such a latch is that an operator may
inadvertently manipulate the handle causing the door to swing open.
Another disadvantage is that an operator may purposely open the
door when it should remain closed. For example, opening the door
may pose a safety hazard to the operator, or allow various subjects
to escape.
SUMMARY OF THE INVENTION
[0012] In accordance with one aspect of the invention, a door
locking system includes an assembly having a first engagement
surface. A door is coupled to the assembly. The door includes a
latch member having a second engagement surface for engaging the
first engagement surface. A movable member is capable of generating
a force against at least one of the assembly and the door to press
together and substantially prevent disengagement of the first
engagement surface and the second engagement surface.
[0013] In accordance with related embodiments of the invention, the
first engagement surface forms an undercut, and the second
engagement surface forms a projection for engaging the undercut.
The latch member may include a post extending from the door, the
post including the second engagement surface. The latch member may
include a handle for operating the latch. The handle may be capable
of pivoting to control alignment of the second engagement surface.
When the first engagement surface is engaged with the second
engagement surface, the movable member generating force against the
one of the door and the assembly may prevent the handle from
pivoting. The movable member may be capable of generating a
continuous force against the at least one of the assembly and the
door. The movable member may be coupled to one of the door and the
assembly and/or positioned between the door and a surface of the
assembly. The movable member may contact the at least one of the
assembly and the door. An element may be positioned between the
movable member and the at least one of the assembly and the door,
such as a pump cassette, wherein the movable member contacts the
element when generating the force.
[0014] In accordance with further related embodiments of the
invention, the movable member is an expandable member, such as a
bladder. A pneumatic circuit may control the movable member.
[0015] In accordance with still further related embodiments of the
invention, the assembly includes a control element for operating a
pump cassette. The control element may include a bezel and a bezel
gasket that includes a membrane capable of being displaced so as to
operate the pump cassette. A pneumatic control circuit may be
utilized to displace the membrane. A cassette receptacle may be
movably coupled to one of the door and the assembly, the cassette
receptacle capable of receiving the pump cassette. The movable
member may be capable of pressing the cassette against the control
element.
[0016] In accordance with another aspect of the invention, a door
locking system includes an assembly having a first engagement
means. A door attached to the assembly includes a second engagement
means for engaging the first engagement means. The system further
includes movable means for generating a force against at least one
of the assembly and the door to press together and substantially
prevent disengagement of the first engagement means and the second
engagement means.
[0017] In accordance with another aspect of the invention, a method
for locking a door is presented. The method includes providing an
assembly that includes a first engagement surface. The assembly is
coupled to a door, the door including a latch member having a
second engagement surface for engaging said first engagement
surface. The method further includes moving a movable member
against at least one of the door and the assembly to press together
and substantially prevent disengagement of the first engagement
surface and the second engagement surface.
[0018] In accordance with related embodiments of the invention, the
first engagement surface forms an undercut. The second engagement
surface may have a projection for engaging the undercut.
[0019] In accordance with further related embodiments of the
invention, a handle may be controlled to operate the latch member.
Prior to moving the movable member against the one of the door and
the assembly, the door may be closed and the handle moved such that
the second engagement surface of the latch member is aligned to
engage the first engaging surface. Opening the door may include
moving the movable member away from the one of the door and the
assembly. The handle can then be moved such that the second
engagement surface is in non-alignment to engage the first engaging
surface, allowing the door to be opened.
[0020] In accordance with still further related embodiments of the
invention, moving the movable member against one of the assembly
and the door includes expanding an expandable member, such as a
bladder. The bladder may be pneumatically operated. A cassette
receptacle may be attached to one of the door and the assembly. A
pump cassette may be inserted into the cassette receptacle. The
assembly may include a membrane capable of being displaced. The
membrane may be pneumatically displaced to operate the pump
cassette. The movable member may be moved against one of the pump
cassette and the cassette receptacle to press the pump cassette
against the membrane.
[0021] In accordance with other related embodiments of the
invention, moving the movable member may include placing the
movable member in contact with the at least one of the assembly and
the door. An element may be placed between the at least one of the
assembly and the door, such that the movable member contacts the
element, such as a pump cassette, generating the force on the at
least one of the assembly and the door.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The foregoing features of the invention will be more readily
understood by reference to the following detailed description,
taken with reference to the accompanying drawings, in which:
[0023] FIG. 1 is a schematic diagram showing a pump system that
includes a door and assembly, in accordance with one embodiment of
the invention;
[0024] FIG. 2 shows a first engagement surface having an undercut,
in accordance with one embodiment of the invention;
[0025] FIG. 3A shows an exploded view of the door assembly in
accordance with an embodiment of the present invention;
[0026] FIG. 3B shows a front perspective view of the door assembly
in accordance with an embodiment of the present invention;
[0027] FIG. 3C shows a rear perspective view of the door assembly
in accordance with an embodiment of the present invention, in which
the cassette receptacle is in a retracted position;
[0028] FIG. 3D shows a rear perspective view of the door assembly
in accordance with an embodiment of the present invention, in which
the cassette receptacle is in an open position;
[0029] FIG. 3E shows a cross-sectional view of an exemplary door
lock system with the door in contact with an occluder blade and the
latch member in an unlatched position, in accordance with an
embodiment of the present invention;
[0030] FIG. 3F shows a cross-sectional view of an exemplary door
lock system with the door rotated inward sufficiently to overcome
the occluder springs and the latch member in an unlatched position,
in accordance with an embodiment of the present invention;
[0031] FIG. 3G shows a cross-sectional view of an exemplary door
lock system with the door fully closed and the latch member in a
latched position, in accordance with an embodiment of the present
invention;
[0032] FIG. 4 is a process flow diagram describing a process for
locking a door, in accordance with one embodiment of the
invention;
[0033] FIG. 5A shows an exemplary blood processing system having a
plurality of blood pumps in accordance with an embodiment of the
present invention;
[0034] FIG. 5B shows an exemplary wiring diagram for one embodiment
of the blood processing system shown in FIG. 1A;
[0035] FIG. 5C shows an exemplary wiring diagram for another
embodiment of the blood processing system shown in FIG. 1A;
[0036] FIG. 6 shows an exemplary blood disposables set in
accordance with an embodiment of the present invention;
[0037] FIG. 7A shows a front view of the pump cassette in
accordance with an embodiment of the present invention;
[0038] FIG. 7B shows a rear view of the pump cassette in accordance
with an embodiment of the present invention;
[0039] FIG. 8 shows a conceptual block diagram of the blood pump in
accordance with an embodiment of the present invention;
[0040] FIG. 9A is an architectural flow diagram showing the
relationship between the pneumatic control assembly and the other
assemblies in accordance with an embodiment of the present
invention;
[0041] FIG. 9B shows an exemplary embodiment of the pneumatic
control assembly in accordance with an embodiment of the present
invention;
[0042] FIG. 10A shows an exploded view of an exemplary front plate
assembly in accordance with an embodiment of the present
invention;
[0043] FIG. 10B shows a front view of an exemplary bezel in
accordance with an embodiment of the present invention;
[0044] FIG. 10C shows a rear view of an exemplary bezel in
accordance with an embodiment of the present invention;
[0045] FIG. 10D shows a front view of an exemplary bezel gasket in
accordance with an embodiment of the present invention;
[0046] FIG. 10E shows a rear view of an exemplary bezel gasket in
accordance with an embodiment of the present invention;
[0047] FIG. 11 shows a side perspective view of the occluder
assembly in accordance with an embodiment of the present
invention;
[0048] FIG. 12 shows a cross-sectional view of an occluder in
accordance with an embodiment of the present invention;
[0049] FIG. 13 shows an exploded view of the occluder assembly in
accordance with an embodiment of the present invention; and
[0050] FIG. 14 is a process flow diagram describing a process for
locking the door using an inflatable bladder, in accordance with an
embodiment of the invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0051] In illustrative embodiments of the present invention, a door
locking system prevents accidental or otherwise inappropriate
opening of a door. To that end, the locking system includes a latch
member that is engaged by a latching structure and a movable
member, which preferably is pneumatically controlled. When properly
positioned, the movable member produces a force that essentially
locks the latch member against the latching structure. An undercut
feature on the latch member and/or the latching structure prevents
disengagement of the latch member when the movable member is
positioned. Details of various embodiments are discussed below.
[0052] FIG. 1 is a schematic diagram showing an assembly 104 that
mixes liquids, such as blood and an anti-pathogen solution
(discussed below). The assembly 104 includes, among other things, a
front plate assembly 408 and a door 402 that is movably attached to
the front plate assembly 408. The door 402 includes a latch member
703 for fastening closed the door 402 to the front plate assembly
408.
[0053] As shown in FIG. 2, the front plate assembly 408 includes a
latching structure 220 for engaging the latch member 703. The
latching structure 220 has an undercut feature forming surfaces 221
and 222. Similarly, the latch member 703 has an undercut feature
forming surfaces 223 and 224. In order to close the door, the door
must be rotated inward past its locking position such that surface
225 travels beyond surface 222, at which point the latch member 703
can be rotated upward such that the surface 223 travels above
surface 221. When the door 402 is closed, the latch member 703 is
engaged by the latching structure 220 such that the surface 223
overlaps the surface 221. Opposing forces are placed on the latch
member 703 and the front plate assembly 408 such that the surfaces
222 and 224 are forced toward one another. With the latch member
703 so engaged, the surface 221 prevents the latch member 703 from
being rotated or otherwise displaced downward due to contact with
the surface 223 and therefore prevents disengagement of the latch
member 703 from the latching structure 220. When the opposing
forces are removed or overcome, the door 402 and latch member 703
can be pushed inward toward the front plate assembly 408 until the
surface 223 no longer overlaps the surface 221 and the latch member
703 can be rotated or otherwise displaced downward to as to
disengage the latch member 703 from the latching structure 220.
[0054] FIG. 3A shows an exploded view of an exemplary embodiment of
the door 402. Among other things, the door assembly 402 includes a
door cowl 701, a latch spring post 702, a door latch 703, a
cassette receptacle 704, a back plate 705, a latch pin 706, a
bladder 707 with an attached pneumatic circuit 730, a frame 708, a
door pin 709, a door mounting bracket 710, a piston assembly 711
including a piston plate 731 and a piston cover 732, a human
interface board assembly 712, double coated tape 713, a miniature
cable tie 714, recessed bumpers 715, E-rings 722, cable tie mount
723, torsion springs 724 and 725, extension spring 726, a cassette
orientation tab 799, and various screws 716, 717, 718, 719, 720,
and 721. The human interface board assembly 712 is mounted to the
inside of the door cowl 701. The door 402 movably attaches to the
assembly 104 via a door mounting bracket 710. The door 402 includes
the latch member 703, which includes a post 740 that extends
through the door 701. The post 740 includes a projection 741, for
engaging the first engagement surface 220 of the assembly 104, as
described above. The cassette receptacle 704 is pivotally mounted
to the frame 708 using the door mounting bracket 710, the door pin
709, and the E-rings 722. Recessed bumpers 715 reduce strain on the
door if the door is opened too far or with excessive force. The
torsion springs 724 and 725 aid the operator in closing the door,
as the door has considerable weight due to the many components. The
cassette orientation tab 799 prevents the door from being closed if
the pump cassette is oriented incorrectly in the cassette
receptacle 704.
[0055] The latch member 703 may include a handle 742 attached to
the post 740, which is accessible from a front side of a door cowl
701. Manipulation of the handle 742, such as by pulling up on the
handle 742, changes alignment of the projection 741 relative to the
first engagement surface 220 of the assembly 101. When the
projection 741 is aligned with the first engagement surface 220,
the door 402 is prevented from being opened due to engagement of
the projection 741 with the first engagement surface 220.
Alternatively, when the projection 741 is not aligned with the
first engagement surface 220, the door 402 is free to swing
open.
[0056] Latch member 703 may be spring-loaded and thus, include a
spring 726 guided by a latch spring post 702. The spring 726 places
a force on the latch member 703 so that when the door 402 is
closed, the projection 741 on latch member 703 snaps into alignment
with the first engagement surface 220 of the assembly 104. To
ensure that the door 402 is properly closed, initial alignment of
the latch member 703 with the first engagement surface 220 may
produce a distinct sound, or cause tactile feedback on the handle
742 that can be felt by the operator.
[0057] To open the door 402, the operator pushes the door 402
inward toward the front plate assembly 408 until the surface 223 no
longer overlaps the surface 221 and rotates the handle 742 upward,
overcoming the force placed on the latch member 703 by the spring
726 and rotating the latch member 703 downward so as to clear the
latching structure 220. The door 402 can then be pulled open.
[0058] In accordance with illustrative embodiments of the
invention, a movable member prevents accidental and/or
inappropriate opening of the closed and latched door 402. To that
end, the movable member is capable of generating a force against at
least one of the front plate assembly 408 and the door 402 to press
together and substantially prevent backing out and disengagement of
the latch member 703.
[0059] The movable member may be a piston assembly, such as the
piston assembly 711, operated by an expandable member, such as the
bladder 707. The expandable member may be made from, among other
things, elastic, resilient, and/or flexible material(s). In other
exemplary embodiments, the movable member may be a rigid structure
controlled by, for example, a motor.
[0060] The bladder 707 may be coupled to the piston assembly 711,
which provides a surface for making contact with the assembly 104.
Among other things, using the piston assembly 711 advantageously
reduces wear on the bladder 707. The piston assembly 711 may attach
to the bladder 707 using, for example, various adhesives known in
the art, such as glue and/or tape 713, which may be double-sided
tape. The piston assembly 711 may include a rigid plate 731 made
of, for example, a hard plastic, that includes a protrusion that is
covered by a piston cover 732. The piston cover 732 can be made of
an elastomer. When the bladder 707 inflates, the piston assembly
711 is pushed toward the frame 708 such that the piston cover 732
protrudes through the frame 708 so that it can be pressed, and in
various embodiments, sealed against a surface on the front plate
assembly 408 or another element (such as a pump cartridge placed in
a cassette receptacle 704, described in detail below) positioned
between the frame 708 and the front plate assembly 408.
[0061] For support, the piston assembly 711 and bladder 707 are
sandwiched between a rigid back plate 705 and the frame 708, which
are mechanically coupled together to form a frame assembly 750. The
frame assembly 750 is mounted to the inside of the door cowl 701 so
that the door latch 703 protrudes through the frame assembly 750
and the frame assembly 750 holds the door latch 703 in place via
latch pin 706. In other embodiments of the present invention, the
frame assembly 750 can be mounted to the assembly 104.
[0062] The bladder 707 is coupled to, and controlled by, a
pneumatic circuit 730 that provides positive and/or negative air
pressure to the bladder 707. Positive pressure supplied to the
bladder 707 causes the bladder 707 to expand in the direction of
the frame 708, since the back plate 707 prevents the bladder from
expanding in the direction of the door cowl 701. This, in turn,
causes the piston assembly 711 to move toward the front plate
assembly 408, such that the piston cover 732 presses against the
front plate assembly 408 or other element positioned between the
piston cover 732 and the front plate assembly 408 (such as a pump
cassette positioned within the cassette receptacle 704), thereby
producing an outward force on the door 402 away from the front
plate assembly 408. Alternatively, supplying negative pressure to
the bladder 707 causes the piston assembly 711 to move away from
the front plate assembly 408 (or other element), thereby reducing
the outward force on the door 402 away from the front plate
assembly 408.
[0063] With a pump cassette positioned in the cassette receptacle
704 and the door 402 in a closed position, pneumatically inflating
the bladder 707 to move the piston assembly 711 toward the front
plate assembly 408 causes the pump cassette to be pressed firmly
against a bezel assembly on the front plate assembly 408, which in
turn produces an outward force on the door 402 away from the front
plate assembly 408. This outward force on the door 402 firmly
engages the latch member 703 and the latching structure 220,
specifically by forcing the surfaces 222 and 224 toward one another
(see FIG. 2). With the latch member 703 so engaged, the surface 221
prevents the latch member 703 from being rotated or otherwise
displaced downward due to contact with the surface 223 and
therefore prevents disengagement of the latch member 703 from the
latching structure 220. As a result, the door 402 is locked, and
the door 402 generally cannot be opened until the bladder is
pneumatically deflated.
[0064] The pneumatic circuit 730 may be precisely controlled by a
control unit 751 that inflates the bladder 707 based on
characteristics of the particular door 402 and/or front plate
assembly 408. The control unit 751 may include, in part, a
microprocessor with associated sensors, logic, and/or memory as
known in the art. The control unit 751 may control the movable
member based on any number of various interlocks. Accidental or
inadvertent manipulation of the handle will not open and/or close
the door unless these various interlocks are met.
[0065] FIG. 3B shows a front perspective view of the door assembly
402 shown in FIG. 3A. A human interface board assembly 712 having
LEDs or other operator controls, and the handle portion of the door
latch 703, are visible from the front of the door cowl 701. A
portion of the cassette receptacle 704 and the pneumatic circuit
730 are also visible.
[0066] FIG. 3C shows a rear perspective view of the door assembly
402 shown in FIG. 3A, in which the cassette receptacle 704 is in a
retracted position. Visible at the rear of the door cowl 701 are
the frame 708, the latch portion of the door latch 703, the
cassette receptacle 704, the piston assembly 711, the door mounting
bracket 710, torsion springs 724 and 725 (which can aid the
operator in closing the door, as the door has considerable weight
due to the many components), a portion of the human interface board
assembly 712, and a portion of the pneumatic circuit 730.
[0067] FIG. 3D shows a rear perspective view of the door assembly
402 shown in FIG. 3A, in which the cassette receptacle 704 is in an
open position. Visible at the rear of the door cowl 701 are the
frame 708, the latch portion of the door latch 703, the cassette
receptacle 704, the piston assembly 711, the door mounting bracket
710, the torsion springs 724 and 725, a portion of the human
interface board assembly 712, and a portion of the pneumatic
circuit 730.
[0068] As discussed above, the door must typically be rotated
inward past its locking position in order to close and open the
door. In order to lock the door when the door is closed, a force is
applied by a movable member such that the latch member is locked
against the latching structure. Among other things, the movable
member prevents or otherwise restricts inward rotation of the door,
making it difficult or impossible to open the door when it is
locked.
[0069] As discussed below, the assembly 104 typically includes an
occluder assembly for occluding one or more pliable plastic tubes
coupled to the pump cassette. The occluder assembly is typically
attached to the back of the front plate assembly 408, and includes
one or more occluder blades that protrude through openings in the
front plate assembly 408 and make contact with corresponding
structures on the door assembly 402 when the door 402 is in a
closed position. Each occluder blade is typically spring loaded and
is pneumatically controlled to permit extension and retraction of
the occluder blade. In exemplary embodiments of the invention, each
occluder blade is held in an extended position by a flat spring and
is retracted by inflating a bladder positioned under the spring so
as to deflect, and thereby shorten the effective length of, the
spring.
[0070] In typical embodiments of the invention, the occluder blades
are positioned so that, when they are in an extended position, they
make contact with the door 402 before the latch member 703 is
engaged by the latching structure 220. In order to close or open
the door, the door 402 must be rotated inward toward the front
plate assembly 408 beyond the extended position of the occluder
blades. The occluder blades can be retracted to facilitate closing
and opening of the door. If, however, the occluder blades are not
retracted (for example, due to a loss of power), then the door 402
must be rotated inward toward the front plate assembly 408 with a
force sufficient to overcome the occluder springs and deflect the
occluder blades inward in order to close or open the door.
[0071] FIG. 3E shows a cross-sectional view of an exemplary door
lock system with the door 402 in contact with an occluder blade 814
and the latch member 703 in an unlatched position, in accordance
with an embodiment of the present invention. The occluder blade 814
is a component of an occluder assembly 404 that is attached to a
back side of the front plate assembly 408, with the occluder blade
814 protruding through a slot in the front plate assembly 408. The
occluder blade 814, which is spring loaded, prevents the door 402
from closing and latching unless and until the door 402 is rotated
inward with sufficient force to overcome the occluder spring.
[0072] FIG. 3F shows a cross-sectional view of an exemplary door
lock system with the door 402 rotated inward sufficiently to
overcome the occluder springs and the latch member 703 in an
unlatched position, in accordance with an embodiment of the present
invention. The occluder blade 814 is shown in its fully extended
position so as to demonstrate the amount of door rotation needed to
overcome the occluder springs.
[0073] FIG. 3G shows a cross-sectional view of an exemplary door
lock system with the door fully closed and the latch member in a
latched position, in accordance with an embodiment of the present
invention. In this position, the latch member 703 is fully engaged
by the latching structure 220 of the front plate assembly 408, and
the occluder blade 814 is deflected inward. In order to open the
door 402 from this position, the door 402 must be rotated inward
until the surface 223 no longer overlaps the surface 221, at which
time the handle 742 can be lifted, causing the latch member 703 to
rotate downward clear of the latching structure 220.
[0074] FIG. 4A shows a process for locking the door 402, in
accordance with an embodiment of the present invention. In block
472, the assembly 104 including the front plate assembly 408 and
the attached door assembly 402 is provided. As shown in FIG. 2, the
front plate assembly 408 includes a latching structure 220 having
an undercut feature defining surfaces 221 and 222, and the door
assembly 402 includes a latch member 703 including an undercut
feature defining surfaces 223 and 224. The process continues by
checking if the door 402 is open, in block 474.
[0075] If the door 402 is open, the door 402 is closed in block
476. As discussed above, the door 402 is preferably closed by
rotating the door 402 inward toward the front plate assembly 408
with sufficient force to overcome the force of the occluders until
the latching structure 220 engages the latch member 703 such that
the surface 223 overlaps the surface 221. Closing the door 402 may
be facilitated by rotating the latch member 703 downward (e.g., by
pulling up on the handle 742) while rotating the door 402 inward.
The latch member 703 is preferably spring loaded, allowing the
latch member 703 to engage with the latching structure 220 when the
door 402 is rotate inward sufficiently.
[0076] When the door 402 is closed (or if the door 402 was already
closed), the process continues by moving a movable member against
at least one of the door 402 and the front plate assembly 408, in
block 478. In exemplary embodiments of the invention, the movable
member includes an inflatable bladder that is situated in the door
402 and, when inflated, pushes the door 402 outward away from the
front plate assembly 408. The movable member causes the surfaces
222 and 224 to be forced toward one another. With the latch member
703 so engaged, the surface 221 prevents the latch member 703 from
being rotated or otherwise displaced downward due to contact with
the surface 223 and therefore prevents disengagement the latch
member 703 from the latching structure 220. Opening of the door 402
by accidental or inappropriate manipulation of the handle 742 is
thus prevented. The system described above may be used in a wide
variety of applications. In exemplary embodiments of the present
invention, an anti-pathogen solution can be mixed with a red blood
cell concentrate (RBCC) to form an incubation solution for reducing
pathogens in the RBCC. The anti-pathogen solution is prepared by
mixing a caustic anti-pathogen compound (e.g., PEN110.TM. or
INACTINE.TM., which is an organic solvent with a pH over 11 that is
distributed by V.I. Technologies, Inc. of Watertown, Mass.) with a
buffer solution of sodium phosphate to a predetermined
concentration (e.g., 1 part anti-pathogen compound to 99 parts
buffer solution), preferably as described in Application D70. For
convenience, this mixing of anti-pathogen compound with buffer
solution may be referred to hereinafter as "compounding," and an
apparatus that performs such compounding may be referred to
hereinafter as a "compounder" or "compounder pump." The incubation
solution is prepared by mixing the anti-pathogen solution with the
RBCC to a predetermined concentration (e.g., 1 part anti-pathogen
solution to 9 parts RBCC), as described below. For convenience,
this mixing of anti-pathogen solution with RBCC may be referred to
hereinafter as "blood processing," and an apparatus that performs
such blood processing may be referred to hereinafter as a "blood
pump." Due to the caustic nature of the anti-pathogen compound, the
system remains must remain in a closed environment to prevent the
operator from being harmed during compounding/blood processing.
Details of a blood processing system incorporating the illustrative
door locking system follow below.
[0077] System Overview
[0078] FIG. 5A shows an exemplary blood processing system 100
having a plurality of blood pumps in accordance with an embodiment
of the present invention. Among other things, the blood processing
system 100 includes a single compounder pump 102 and ten
essentially identical blood pumps 104 organized as two banks of
five blood pumps each. The compounder pump 102 pumps buffer
solution from a buffer solution container 110 into a vial of
anti-pathogen compound 108. The mixture, referred to as a working
solution, is pumped into a working solution container 112. Each of
the blood pumps 104 mixes working solution from the working
solution container 112 with red blood cell concentrate (RBCC) from
a RBCC container 106 to form an incubation solution that is pumped
into an incubation bag 118. The incubation solution is typically
allowed to incubate for some period of time, after which it is
rinsed to remove the anti-pathogen compound to produce a pathogen
reduced blood product. The blood processing system 100 typically
also includes two sterile docks 114 that are used by the operator
to splice together plastic tubing as necessary for various blood
processing operations. The blood processing system 100 is
controlled through a user interface 116.
[0079] FIG. 5B shows an exemplary wiring diagram for one embodiment
of the blood processing system 100. The compounder pump 102 and the
blood pumps 104 are typically powered from a common 12-Volt
external power supply 126, and are controlled by an external
process controller 120. The process controller 120 includes the
user interface 116, a computer 122, and a serial port concentrator
124. The compounder pump 102 and the blood pumps 104 are in
communication with the process controller 120 through the serial
port concentrator 124, for example, over RS-232 communication
links. The blood processing system 100 typically includes a tubing
sealer 130 for sealing plastic tubing as necessary for various
blood processing operations. The blood processing system 100
typically includes an uninterruptible power supply (UPS) 128 for
maintaining electrical power to the 12-Volt power supply, the
process controller, and other components in the event of a primary
power loss.
[0080] FIG. 5C shows an exemplary wiring diagram for another
embodiment of the blood processing system 100. The blood processing
system 100 may include a printer in communication with the process
controller for printing out reports. The blood processing system
100 may include a card reader 134 in communication with the process
controller for card-based operator identification. The blood
processing system 100 may include a wireless bar code scanner base
station 138 in communication with the process controller for
receiving bar code information scanned using a wireless bar code
scanner 136. Bar codes are typically used to track the various
solution containers and the pumps on which those containers were
processed.
[0081] The process controller 120 coordinates the actions of the
compounder pump 102, the blood pumps 104, and the operator
throughout the various mixing operations, as described in greater
detail in Application D72. The process controller 120 initiates
high level embedded commands within the pumps to move and mix the
fluids. The process controller 120 instructs the operator through
the setup and teardown of each process through the user interface
116. The user interface 116 is also used to inform the operator of
any anomalies that may occur during mixing operations.
[0082] When the blood processing system 100 is operating from the
uninterruptible power supply 128 and at other appropriate times,
the process controller 120 will prevent compounding and other pump
operations from starting, although the pumps will generally be
allowed to complete any ongoing operations. Furthermore, if the
process controller fails, the pumps have internal logic for safely
completing or terminating any ongoing operations.
[0083] Blood Disposables
[0084] In an exemplary embodiment of the present invention, the
process controller 120 coordinates blood processing for an entire
bank of five blood pumps 104 at a time. Specifically, five pump
cassettes, each connected to a RBCC container and an incubation bag
for receiving the incubation solution, are loaded respectively into
the five blood pumps 104. The five pump cassettes are preferably
connected by a single working solution inlet tube to the working
solution container so that all five blood pumps draw working
solution from the single working solution container. For
convenience, the five interconnected pump cassettes along with
their respective incubation bags and various plastic tubing may be
referred to hereinafter as a "blood disposables set." The blood
disposables set is preferably used for a single blood processing
cycle and is then discarded. The blood disposables set is described
in greater detail in Application D85.
[0085] FIG. 6 shows an exemplary blood disposables set 200 in
accordance with an embodiment of the present invention. The blood
disposables set 200 includes five pump cassettes 202.sub.1-5, each
respectively having a RBCC inlet tube 204.sub.1-5 connected to an
RBC inlet port of the pump cassette and an incubation solution
outlet tube 206.sub.1-5 connected to an outlet port of the pump
cassette and to an incubation bag 118.sub.1-5. The blood
disposables set 200 also includes working solution distribution
tubing 212 that connects to a working solution inlet port on each
pump cassette 202.sub.1-5 and to a single working solution inlet
tube 210 so that the working solution inlet ports of all pump
cassettes 202.sub.1-5 are effectively connected to the single
working solution inlet tube 210. The working solution inlet tube
210 preferably connects to the working solution distribution tubing
212 close to where the working solution inlet port of the middle
pump cassette 202.sub.3 connects to the tubing 212, and the working
solution inlet ports of each concentric pair of pump cassettes is
preferably connected to the tubing 212 a substantially equal
distance from that center connection such that the working solution
inlet ports of the pump cassettes 202.sub.1 and 202.sub.5 are
essentially equidistant from the center connection and the working
solution inlet ports of the pump cassettes 202.sub.2 and 202.sub.4
are essentially equidistant from the center connection. Among other
things, this spacing of pump cassettes along the tubing 212
facilitates priming of the pumps, as discussed below. In order to
perform blood processing, each RBCC inlet tube 204 is connected to
a separate RBCC container 106, and the working solution inlet tube
210 is connected to the common working solution container 112. The
blood disposables set 200 also includes six break-away closures
214, one on each of the RBCC inlet tubes 204 and one on the working
solution inlet tube 210. In order to reduce the likelihood of
confusing which RBCC bag and which incubation bag is associated
with each pump cassette, the RBCC inlet tubes 204 and the
incubation solution outlet tubes 206 are preferably coded, for
example, by alternating between color-striped and clear tubing from
cassette to cassette.
[0086] FIG. 7A shows a front view of the pump cassette 202 in
accordance with an embodiment of the present invention. The pump
cassette 202 is essentially a rigid core including formations and
sealing ribs 340 constituting various pumping chambers, fluid
valves, and fluid pathways (channels). The rigid core is covered on
each side by a flexible membrane (e.g., a flexible PVC sheet). The
flexible membranes seal against the core and isolate the blood pump
104 from fluids within the cassette. The pump cassette 202 is
designed to interface with the blood pump 104 in only one
direction. For example, the pump cassette 202 typically includes an
asymmetric feature (such as the placement of tubing) that prevents
the blood pump door from closing if the pump cassette 202 is
inserted incorrectly.
[0087] Among other things, the pump cassette 202 includes a working
solution inlet port 304, an RBC inlet port 305, a vent port 307, an
outlet port 308 and two pumping chambers, namely a working solution
chamber 333 and an RBC chamber 334. During blood processing,
working solution from the working solution container 112 is drawn
into the working solution chamber 333 through the tubing 210 and
212 and the working solution inlet port 304, and is pumped from the
working solution chamber 333 into the channel 310 while RBCC from
the RBCC container 106 is drawn into the RBC chamber 334 through
the RBCC inlet tube 204, the RBCC inlet port 305, and the channel
310. This causes the working solution and RBCC to be mixed within
the channel 310 and the RBC chamber 334. The mixture (incubation
solution) is pumped from the RBC chamber 334 to the incubation bag
118 through the outlet port 308 and the incubation solution outlet
tube 206.
[0088] FIG. 7B shows a rear view of the pump cassette 202 in
accordance with an embodiment of the present invention. The rears
view of the pump cassette 202 shows various "volcano" valves that
are used to open and close various fluid pathways within the pump
cassette 202. The valves include an RBC priming valve 326, an RBC
valve 328, an incubation bag valve 330, a working solution valve
332, and a working solution connection to RBC line valve 336. The
volcano valves and the pumping chambers are all operated
pneumatically from the rear of the pump cassette 202, as discussed
below.
[0089] Blood Pump
[0090] As discussed above, each blood pump 104 prepares incubation
solution by mixing an anti-pathogen solution with RBCC. A
disposable pump cassette 202 is used to handle the various fluids.
The pump cassette 202 serves as an interface between the blood pump
104, the RBCC container 106, and the incubation bag 118 so that no
working solution, RBCC, or incubation solution comes into actual
contact with the components of the blood pump 104. The blood pump
104 preferably uses pneumatics to operate the pump cassette 202 as
well as other components, as discussed below.
[0091] The blood pump 104 produces the incubation solution by
causing working solution to be drawn into the working solution
chamber 333 and pumping working solution from the working solution
chamber 333 into the channel 310 while drawing RBCC into the RBC
chamber 334 through the channel 310. This causes the working
solution and RBCC to be mixed within the channel 310 and the RBC
chamber 334. The mixture (incubation solution) is pumped from the
RBC chamber 334 to the incubation bag 118 through the outlet port
308.
[0092] In a typical embodiment of the present invention, the
working solution is pumped from the working solution chamber 333
using a pulsing technique in which small quantities of working
solution are pumped at predetermined intervals and the pulsing of
working solution is adjusted periodically using a closed feedback
loop in order to produce an incubation solution having a
predetermined concentration of working solution, with predetermined
limits. Specifically, the working solution is delivered in a
pulsatile mode where the pulse width of the exit valve on the
working solution chamber is controlled. The fluid valve is pulsed
at a pulse width and interval that is predetermined for each
pumping stroke and is adjusted stroke-by-stroke according to the
amounts of working solution and RBCC pumped, as described below.
The blood pump 104 can support pulse widths above some minimum
value, and the interval between pulses is increased in order to
achieve an effective pulse width below the minimum value.
[0093] The blood pump 104 preferably includes a library of generic
pump control (N-Pump) functions. The N-Pump library functions are
used to perform various generic pumping operations such as, for
example, pumping fluid into a chamber of the pump cassette, pumping
fluid out of a chamber of the pump cassette, measuring the amount
of fluid pumped, performing air detection, and maintaining tank
pressures. The blood pump 104 preferably also includes a Fluid
Logic Module (FLM) that contains higher level functions that employ
the N-Pump library functions to implement application-specific
functions (such as specific logic for mixing the working solution
with the RBCC to produce the incubation solution).
[0094] The blood pump 104 includes one master board connected to
two pump boards that together perform the N-Pump and FLM functions.
The master board communicates to each of the pump boards via a
multi-drop RS-485 bus. Each pump board controls a single pump
chamber of the pump cassette 202 and the valves on its board.
[0095] FIG. 8 shows a conceptual block diagram of the blood pump
104 in accordance with an embodiment of the present invention.
Among other things, the blood pump 104 includes a door assembly 402
as described in above embodiments, an occluder assembly 404, a
front plate assembly 408, a pneumatic control assembly 410, a
power/communication interface 412 including connectors for the
12-Volt power supply and the RS-232 communication link to the
process controller 120, and chassis components 414. Each of these
assemblies is discussed below.
[0096] Pneumatic Control Assembly
[0097] The pneumatic control assembly 410 provides positive and
negative air pressure for operating the various other pneumatically
controlled components and also acts as the general controller for
the blood pump 104. The pneumatic control assembly 410 contains
three electromechanical pump module assemblies, namely a tank
management module assembly and two chamber module assemblies (one
for the working solution pump chamber and one for the RBC pump
chamber). Each pump module assembly includes an aluminum manifold,
pneumatic valves, pneumatic fittings, a valve interface board, and
an electronics board that includes pressure transducers and a
dedicated microprocessor. The tank management module assembly
handles all communication between the blood pump and the process
controller 120, synchronizes pumping of the chamber module
assemblies, maintains positive and negative air pressure in various
accumulators, seals and unseals the door assembly, engages and
disengages the occluders, monitors the door open/closed status, and
monitors the air-in-line sensor, as described below. Each chamber
management assembly controls a separate one of the pump chambers,
and also controls the fluid valves associated with the pump chamber
and measures the volume of liquids pumped through the pump
chamber.
[0098] FIG. 9A is an architectural flow diagram showing the
relationship between the pneumatic control assembly 410 and the
other assemblies in accordance with an embodiment of the present
invention. In this figure, the pneumatic control assembly 410 is
represented by master module 512, accumulator assembly 513, working
solution pump module 514, and RBCC pump module 515. The air pump
511 is considered to be one of the chassis components 414. The air
pump 511 generates high and low air pressure for the master module
512, which stores high and low air pressure in the accumulator
assembly 513. The pneumatic control assembly 410 directs air
pressure (positive and negative) to the various pneumatic
mechanisms of the pump. The master module 512 pneumatically
controls bladders in the occluder assembly 404 and a bladder in the
door assembly 402. The master module 512 provides high and low air
pressure to the working solution pump module 514 and the RBCC pump
module 515. The working solution pump module 514 controls the
working solution chamber 333 and associated valves of the pump
cassette 202 through the front plate assembly 408, and the RBCC
pump module 515 controls the RBC chamber 334 and associated valves
of the pump cassette 202 through the front plate assembly 408, as
described below.
[0099] FIG. 9B shows an exemplary embodiment of the pneumatic
control assembly 410 in accordance with an embodiment of the
present invention. Among other things, the pneumatic control
assembly 410 includes manifold mounting bracket 502, a negative
pressure accumulator (pressure bottle) 513a, a positive pressure
accumulator (pressure bottle) 513b, a manual door vent mechanism
503, the Tank Management Module Assembly 512, the two Chamber
Module Assemblies 514 and 515, and associated tubing and
fittings.
[0100] The tank management module 512 includes an input/output
(I/O) board, a CPU board, a valve-interface board, a pneumatic
manifold system, pneumatic valves, pressure transducers 2-vent
covers (mufflers), stand-offs, and associated tubing and fittings.
The tank management module 512 is used to control the pressures in
the accumulators 513, the bladder in the door assembly 402, and
bladders in the occluder assembly 404. The I/O board contains
electrical controls for controlling LEDs that provide status
information to the operator. The pressure transducers are used to
monitor the pressures of the accumulators 513 and the bladder in
the door assembly 402.
[0101] In the un-powered state, the pneumatic valve that controls
flow to the bladder in the door assembly 402 preferably shuts
closed. This prevents the door from being opened in the event of a
loss of power.
[0102] In the un-powered state, the pneumatic valves that control
flow to the bladders in the occluder assembly 404 are preferably
channeled to vent. This causes the occluders to occlude the tubing
to prevent further flow of fluid through the tubing, as discussed
below.
[0103] Each chamber module 514 and 515 includes a CPU board, a
valve interface board, pneumatic manifold system, pneumatic valves
(including a VSO (variable) valve), a VSX chamber (504 and 505
respectively), O-ring, copper mesh, vent cover (muffler),
stand-offs, pressure transducers, and associated tubing and
fittings. Each chamber module assembly controls the pneumatics for
one of the pumping chambers and its associated valves. The VSX
chambers 504 and 505 act as reference volumes in order to measure
the volume of fluid that is delivered with the FMS system. The
pressure transducers are used to monitor the pressure of the VSX
chamber, and of the pumping chamber. The positive pneumatic system
contains a pressure relief valve to prevent the air pump from
pressurizing the positive system to greater than 16.0 psig.
[0104] In the un-powered state, all of the pneumatic valves
preferably open the fluid valves to the positive pressure line.
This ensures that the fluid valves are closed if there is a loss of
power.
[0105] The blood pump 104 typically includes three microprocessor
systems, one on the tank management module 512 and one on each of
the chamber modules 514 and 515. These three microprocessor systems
monitor each other for normal operation. Each microprocessor system
also monitors key internal processes and data for validity. If any
of these monitors fail, a failsafe line permits any of the three
processors to stop pumping operations, close all of the fluid
valves and occluder, and send an anomaly signal to the process
controller. If the blood pump 104 detects an anomaly with the
commands received from the process controller (e.g., commands
received out of sequence), then the blood pump 104 will stop fluid
flow and send an anomaly signal to the process controller.
[0106] Front Plate Assembly
[0107] The front plate assembly includes all necessary pneumatic
pathways to interface to the disposable pump cassette 202. The
front plate assembly 408 includes a bezel and a bezel gasket
through which the pump cassette 202 is operated. During operation
of the blood pump 104, the pump cassette 202 is positioned in the
door assembly 402 and is pressed against the front plate assembly
408 in alignment with the bezel and bezel gasket by a bladder in
the door assembly 402, as discussed below. Air lines connected to
the bezel from the pneumatic control assembly 410 are used to
displace membranes of the bezel gasket to operate the various
valves and chambers of the pump cassette 202.
[0108] FIG. 10A shows an exploded view of an exemplary front plate
assembly 408 in accordance with an embodiment of the present
invention. Among other things, the front plate assembly 408
includes a rigid front plate 602 to which are mounted a bezel 604,
chamber foam 606, spacer 608, air-in-line sensor 610, bezel gasket
612, gasket retainer 614, hardware 616, dowel pins 618, and grommet
620. The bezel 604, chamber foam 606, and bezel gasket 612 are
mounted to the front plate 602 by the gasket retainer 614 and
associated hardware 616, forming a bezel assembly. This bezel
assembly is used to control pumping and mixing of fluids using the
pump cassette 202, as described below. The front plate 602 includes
holes for allowing air tubes to pass between the rear of the bezel
604 and the pneumatic control assembly 410, which is typically
situated behind the front plate 602. The front plate 602 also
includes openings for occluder blades and for engaging a door latch
mechanism, as described below. The air-in-line sensor 610 is
positioned so as to align with and engage the RBCC inlet tube 204,
and is used during blood processing to detect air in the RBCC inlet
tube 204 indicating that there is no more RBCC to be processed.
[0109] FIG. 10B shows a front view of an exemplary bezel 604 in
accordance with an embodiment of the present invention. The bezel
604 is preferably a molded polycarbonate/ABS unit including, among
other things, a working solution chamber cavity 633 for operating
the working solution chamber 333 of the pump cassette 202, an RBC
chamber cavity 634 for operating the RBC chamber 334 of the pump
cassette 202, and various valve cavities 635 for operating the
various valves of the pump cassette 202. The working solution
chamber cavity 633 is preferably molded with rib structures 636
that allow for airflow within the working solution chamber cavity
633 but mechanically restrict the amount of working solution that
can be drawn into the working solution chamber 333 of the pump
cassette 202. The compounder 102 preferably uses the same molded
bezel 604 as the blood pump 104, but with the rib structures 636
removed (e.g., by precision machining) to allow for greater pumping
capacity. The bezel is described in greater detail in Application
D75.
[0110] FIG. 10C shows a rear view of the bezel 604 in accordance
with an embodiment of the present invention. The bezel 604 includes
integral solvent bondable tubing connections (ports) 637 to which
pneumatic tubing from the pneumatic control assembly 410 are
connected. In this embodiment, each of the valve cavities 635 is
associated with a single integral port 637, and each of the chamber
cavities 633 and 634 are associated with two integral ports 637.
The integral ports 637 allow the pneumatic connections to be made
without independent fittings and accompanying O-rings.
[0111] FIG. 10D shows a front view of an exemplary bezel gasket 612
in accordance with an embodiment of the present invention. The
bezel gasket 612 fits over the front of the bezel 604 and acts as
an interface between the bezel 604 and the pump cassette 202 for
sealing the fluid paths of the pump cassette 202 and for actuating
the chambers and valves of the pump cassette 202. The pump cassette
202 is pressed firmly against the front side of the bezel gasket
612 during blood processing in order to produce an air-tight seal
between the bezel gasket 612 and the pump cassette 202. The bezel
gasket 612 includes membranes that correspond to the chamber
cavities and valve cavities. Positive and negative air pressure
produced through the bezel cavities operate on the bezel gasket
membranes, which in turn operate on the chambers and valves of the
pump cassette 202.
[0112] FIG. 10E shows a rear view of an exemplary bezel gasket 612
in accordance with an embodiment of the present invention. The rear
side of the bezel gasket 612 contacts the front side of the bezel
604, and is pressed firmly against the bezel 604 during blood
processing in order to produce an air-tight seal. The bezel gasket
612 includes membranes that correspond to the chamber cavities and
valve cavities. Positive and negative air pressure produced through
the bezel cavities operate on the bezel gasket membranes, which in
turn operate on the chambers and valves of the pump cassette
202.
[0113] Door Assembly
[0114] The door assembly 402 mounts to the front plate assembly
408, and provides a means to load and align the disposable pump
cassette 202 in a cassette receptacle 704 within the blood pump
104. The door assembly 402 provides a force on the pump cassette
202 against the bezel assembly of the front plate assembly 408 in
order to provide sealing of the cassette's fluid paths and valves,
as described in greater detail in Application D73. The door
assembly 402 also provides a surface for the occluders to function
against, as described below.
[0115] Referring back to FIG. 3A, the door assembly 402 is designed
to permit single-handed operation, specifically by pulling up on
the handle. However, the door latch 703 is designed, similar to
above-described embodiments, so that the door cannot be easily
opened when the pump cassette 202 is in place in the cassette
receptacle 704 with the door closed and the piston assembly 711 is
inflated. Specifically, the latch portions of the door latch 703
have undercuts that engage with recesses in the front plate
assembly 408. When the pump cassette is in place in the cassette
receptacle 704 with the door closed and the piston assembly 711 is
inflated so as to push the pump cassette 202 against the bezel
assembly of the front plate assembly 408, a sufficient force is
generated between the door assembly 402 and the front plate
assembly 408 to prevent the door handle from being easily
lifted.
[0116] Occluder Assembly
[0117] The occluder assembly 404 mounts to the back of the front
plate assembly 408, and is used to selectively occlude the RBCC
inlet tube 204, the incubation solution outlet tube 206, and the
working solution distribution tube 212 as needed for testing, blood
processing, and protection in the event of a failure. In the blood
pump 104, the occluder assembly 404 includes two occluders, one
operating on both the RBCC inlet tube 204 and the incubation
solution outlet tube 206, and the other operating on the working
solution distribution tube 212. The occluders are controlled
pneumatically, and can be controlled independently.
[0118] In a typical embodiment of the present invention, each
occluder includes an occluder blade that is operated by a flat
spring and an inflatable bladder. The occluder blade is coupled to
one end of the spring. When the bladder is deflated, the spring
extends the occluder blade into an occluding position, which blocks
the passage of fluid through the tube(s). When the bladder is
inflated, the bladder bends the spring so as to retract the
occluder blade from the occluding position, which enables the
passage of fluid through the tube(s). In the event of a loss of
pneumatics, the occluder defaults to the occluded position so as to
prevent fluid from passing through the tubing.
[0119] FIG. 11 shows a side perspective view of the occluder
assembly 404 in accordance with an embodiment of the present
invention. The occluder assembly 404 includes, among other things,
a bottom housing 801, a top housing 802, a first occluder having an
occluder blade 813 and other components operated pneumatically
through tube 803, and a second occluder having an occluder blade
814 and other components operated pneumatically through tube 804.
The occluder assembly 404 is mounted to the front plate assembly
408, with the occluder blades 813 and 814 protruding through slots
in the front plate assembly 804. The tubes 803 and 804 are
connected to the pneumatic control assembly 410.
[0120] FIG. 12 shows a cross-sectional view of an occluder in
accordance with an embodiment of the present invention. Among other
things, the occluder includes a flat occluder spring 812 having a
rear end coupled to the top housing 802 and a front end coupled to
the occluder blade 814, a bladder 808 situated between the top
housing 802 and the spring 812, the tube 804 coupled to the bladder
808, and an adjuster 810 for adjusting the protrusion of the
occluder blade 814. When the bladder 808 is inflated, the occluder
spring 812 is deflected downward at the middle so as to shorten the
effective length of the occluder spring 812 and retract the
occluder blade 814. When the bladder 808 is deflated, the occluder
spring 812 extends flat and therefore extends the occluder blade
814. The occluder blade 814 moves within guides (not shown) that
allow the spring to extend and retract the occluder blade 814.
[0121] FIG. 13 shows an exploded view of the occluder assembly 404
in accordance with an embodiment of the present invention. Among
other things, the occluder assembly 404 includes enclosure top 802,
enclosure bottom 810, a first occluder including an occluder blade
813, a shaft 821, a front bracket 819, a rear bracket 817, a
bladder 809, and a tube 803, and a second occluder including an
occluder blade 814, a shaft 820, a front bracket 818, a rear
bracket 816, a bladder 808, and a tube 804. The rear brackets 816
and 817 are mounted to the enclosure top 802 via shaft 825, blocks
826 and 827, and clamps 828 and 829. The rear brackets 816 and 817
are held in a substantially fixed position, although the rear
brackets 816 and 817 are able to rotate about the shaft 825 as
needed for operation of the occluders. The front bracket 819 is
mounted to the enclosure top 802 via shaft 821 and sliding blocks
823 and 824, while the front bracket 818 is mounted to the
enclosure top 802 via shaft 820 and sliding blocks 822 and 823. The
front brackets 818 and 819 are able to slide forward and backward
along channels formed in the sliding blocks 822, 823, and 824 as
needed for operation of the occluders. The occluder blades 813 and
814 can be manually retracted if necessary. The edge of the
occluder blades 813 and 814 that engages the tubing are typically
rounded so as not to cut or crease the tubing.
[0122] Chassis Components
[0123] The chassis components 414 include various mechanical
hardware components that are not considered part of the other
assemblies. Among other things, the chassis components 414 include
the DC air pump 511, a chassis base, a door sensor (and cable),
mounting foot grommets, skins (housing), and associated hardware
and fasteners. The housing includes a mounting point, on the back
of the unit, for the manual piston bladder (door) vent 503.
[0124] Pump Cassette Handling
[0125] Referring back to FIG. 1, the pump cassette 202 is installed
in the blood pump 104 in accordance with an embodiment of the
present invention. Particularly, the pump cassette 202 is installed
in the cassette receptacle 704. The door assembly 402 will only
close if the pump cassette 202 is oriented correctly in the
cassette receptacle 704, and will not close if the pump cassette
202 is inserted backwards so that the tubing connected to the pump
cassette 202 does not align with corresponding channels in the door
latch 703. When the door assembly 402 is closed and the bladder in
the door assembly 402 is inflated, the pump cassette 202 is pressed
tightly against the bezel gasket 612 and gasket retainer 614 on the
front panel assembly 408, preventing the door assembly 402 from
being opened. Additionally, the RBCC inlet tube 204 is captured by
the air-in-line sensor 610 on the front plate assembly 408, the
occluder blade 813 aligns with and occludes the working solution
distribution tube 212, and the occluder blade 814 aligns with and
occludes both the RBCC inlet tube 204 and the incubation solution
outlet tube 206.
[0126] Door Locking/Unlocking
[0127] FIG. 14 shows a process for locking the door 402 using the
inflatable bladder 707, in accordance with one embodiment of the
invention. The process begins by inflating the bladder 707, in
block 480. Positive pressure is supplied to the bladder 707 via the
pneumatic circuit 730, which is precisely controlled by the control
unit 751. The control unit 751 may start inflating the bladder 707
based on a wide variety of safety and procedural interlocks. These
interlocks may be based, for example, on a signal received from a
sensor, such as the door 402 being closed, and/or on an operator
input, such as an input from an operator interface indicating a
pumping procedure is ready to begin.
[0128] The process continues with the bladder 711 generating a
force against at least one of the assembly 104 and the door 402, in
block 482. Inflating the bladder 707 causes the membrane 732 of the
bladder piston 711 to protrude through the frame 708. As inflation
continues, the membrane 732 contacts the door 402 and/or assembly
104, generating a force directed at pushing the door 402 (i.e., the
back plate 705) and assembly 104 apart. This, in turn, presses the
aligned first and second engagement surfaces 220 and 221 tightly
together, preventing disengagement of the latch member 703 and thus
locking the door 402.
[0129] In various embodiments, the membrane 732 may advantageously
contact another element instead of, or in combination with, the
door 402 and assembly 104. For example, a pump cassette may be
positioned between the membrane 732 and the at least one of the
door 402 or assembly 104. The membrane 732 pressing on the pump
cassette forces the pump cassette against the door 402 or assembly
104, generating a force directed at pushing apart the door 402 and
assembly 101. Consequently, similar to the above-described
embodiment, the first and second engagement surfaces 220 and 221
are pressed firmly together, locking the door 402.
[0130] The control unit 751 continues to inflate the bladder 711
until a force is generated on the at least one of the door 402 and
assembly 104 to sufficiently prevent an operator from disengaging
the latch member 703, block 484. In various embodiments, the air
pressure of the bladder 711 that is required to ensure locking of
the door 401 is a predetermined value. The control unit 751
controls the pneumatic circuit 730 to stop inflating the bladder
711 when the predertermined value is met, and maintains the
bladder's air pressure at the predetermined value, block 486. Thus,
a constant force is applied on the at least one of the door 402 and
the assembly 104, keeping the door 401 locked.
[0131] To unlock the door 402, the control unit 751 controls the
pneumatic circuit 730 to deflate the bladder 711. This causes the
piston 711 to move away from the door 402 and/or assembly 104 (or
other element), allowing sufficient play between the engagement
surfaces 220 and 221 such that the latch member 703 can be
disengaged from the assembly 104. In other words, the piston 711 no
longer generates a sufficiently large locking force against the
noted elements. Consequently, the two surfaces 220 and 221 can
disengage from one another.
[0132] Manual Teardown
[0133] During normal blood pump teardown, the blood pump 104
receives commands from the process controller 120 to release
pressure against the pump door so that the door can be opened by
the operator. The pressure against the door comes from both the
door piston bladder and the occluders. While the door piston
bladder is pressurized and the tubing occluders are engaged, it is
virtually impossible for the operator to open the pump door and
remove the pump cassette. If communication between the process
controller 120 and the blood pump 104 is lost, then the operator
will need to relieve this pressure manually in order to remove the
cassette. Among other things, this involves the operator pressing
the manual door release valve on the back of the pump to deflate
the bladder in the door assembly. The operator may also manually
retract the occluders if necessary.
[0134] It should also be noted that the flow diagrams are used
herein to demonstrate various aspects of the invention, and should
not be construed to limit the present invention to any particular
flow or implementation. In some cases, certain process steps can be
omitted or performed in a different order than shown without
changing the overall results or otherwise departing from the true
scope of the invention.
[0135] The present invention may be embodied in other specific
forms without departing from the true scope of the invention. The
described embodiments are to be considered in all respects only as
illustrative and not restrictive.
* * * * *