U.S. patent application number 12/324365 was filed with the patent office on 2009-03-19 for fluid flow restriction indicator.
This patent application is currently assigned to Engineered Products Company. Invention is credited to Charles Henry Berry, III, H. Dianne Hammerand.
Application Number | 20090071392 12/324365 |
Document ID | / |
Family ID | 36289956 |
Filed Date | 2009-03-19 |
United States Patent
Application |
20090071392 |
Kind Code |
A1 |
Berry, III; Charles Henry ;
et al. |
March 19, 2009 |
FLUID FLOW RESTRICTION INDICATOR
Abstract
An indicator suitable for signaling restricted flow of a fluid
through a filter mounted in a filter indicator includes a housing
having an inner cavity. A diaphragm disposed within the housing
separates the inner cavity into first and second chambers and
deflects from a neutral position in response to applied pressures
within the first and second chambers. A tab assembly opposite the
diaphragm includes a spring-loaded flag moveable from a first
position within the housing to a second position outside the
housing. A pin operably coupled to the diaphragm holds the
spring-loaded flag within the housing when the diaphragm is in the
neutral position. In response to the diaphragm being deflected
sufficiently from the neutral position to release the pin, the
spring-loaded flag travels to the second position outside of the
housing, thereby indicating a restrictive flow condition for the
filter.
Inventors: |
Berry, III; Charles Henry;
(Cedar Falls, IA) ; Hammerand; H. Dianne; (Vinton,
IA) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG & WOESSNER, P.A.
P.O. BOX 2938
MINNEAPOLIS
MN
55402
US
|
Assignee: |
Engineered Products Company
Waterloo
IA
|
Family ID: |
36289956 |
Appl. No.: |
12/324365 |
Filed: |
November 26, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11040913 |
Jan 21, 2005 |
7470360 |
|
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12324365 |
|
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Current U.S.
Class: |
116/273 ;
210/90 |
Current CPC
Class: |
B01D 46/446 20130101;
Y10S 116/25 20130101; B01D 46/0086 20130101; B01D 2265/029
20130101; B01D 2265/025 20130101; Y10S 55/34 20130101; F02M 35/09
20130101; B01D 46/543 20130101 |
Class at
Publication: |
116/273 ;
210/90 |
International
Class: |
G01F 15/00 20060101
G01F015/00; B01D 35/143 20060101 B01D035/143 |
Claims
1. An indicator suitable for signaling restricted flow of a fluid
through a filter mounted in a filter assembly, the indicator
comprising: a housing having an inner cavity; a deflectable
diaphragm disposed within the housing and separating the inner
cavity into first and second chambers with a generally fluid-tight
seal, wherein the first chamber is adapted to be in fluid
communication with the filter assembly, wherein the diaphragm is
deflectable from a neutral position in response to applied
pressures within the first and second chambers; a tab assembly
having a hole through the tab assembly, the tab assembly including
a flag moveable along a first axis from a first position wherein
the flag is within the housing and a second position wherein the
flag extends from the housing, the tab assembly opposite the
diaphragm from the first chamber; a pin operably coupled to the
diaphragm and protruding along a second axis from the diaphragm
into the hole and through the tab assembly when the diaphragm is in
at least the neutral position, wherein the second axis is
nonparallel to the first axis; and wherein movement of the flag
from the first position to the second position is actuated in
response to the diaphragm being deflected a selected amount from
the neutral position into the first chamber and the pin being
removed from the tab assembly.
2. The indicator of claim 1 wherein the diaphragm resists movement
from the neutral position into the first chamber with a biasing
member.
3. The indicator of claim 2 wherein the biasing member is a
spring.
4. The indicator of claim 3 wherein the spring is disposed in the
first chamber and against the housing and the diaphragm.
5. The indicator of claim 4 wherein the diaphragm includes a
deflectable member and a relatively stiff inner member, and wherein
the inner member interfaces with the spring.
6. The indicator of claim 1 wherein the diaphragm has a width, and
the width is greater than a length of the inner cavity measured
along the second axis.
7. The indicator of claim 6 wherein the diaphragm is circular and
the width is a diameter of the circular diaphragm.
8. The indicator of claim 1 wherein the tab assembly includes a
reset spring, and wherein the tab assembly is biased in the first
position with the reset spring and urged toward the second
position.
9. The indicator of claim 8 wherein the reset spring acts against
the housing and flag.
10. The indicator of claim 8, and further comprising a guide plate
disposed in the second chamber between the diaphragm and the tab
assembly.
11. The indicator of claim 10 wherein the reset spring acts against
the guide plate and the flag.
12. The indicator of claim 10 wherein the guide plate includes a
hole adapted to receive the pin.
13. The indicator of claim 1 wherein the first axis is generally
perpendicular to the second axis.
14. An indicator suitable for signaling restricted flow of a fluid
through a filter mounted in a filter assembly, the indicator
comprising: a housing having a base and a cover defining an inner
cavity; a deflectable diaphragm disposed within the housing and
separating the inner cavity into first and second chambers with a
generally fluid-tight seal, wherein the base and diaphragm at least
partially define the first chamber, and the cover and diaphragm at
least partially define the second chamber; a calibration spring
disposed in the first chamber and acting against the base and
diaphragm to resists movement of the diaphragm from a neutral
position; wherein the first chamber is adapted to be in fluid
communication with the filter assembly and the diaphragm is
deflectable from the neutral position in response to applied
pressures within the first and second chambers; a tab assembly
having a hole through the tab assembly, the tab assembly including
a flag and a reset spring, wherein the flag is moveable along a
first axis from a first position wherein the flag is within the
housing and a second position wherein the flag extends from the
housing, the tab assembly opposite the diaphragm from the first
chamber; a guide plate disposed in the second chamber between the
diaphragm and the tab assembly, the guide plate having a main
surface, wherein the main surface is spaced-apart from the cover; a
pin operably coupled to the diaphragm and protruding along a second
axis from the diaphragm through the guide plate and into the hole
and through the tab assembly when the diaphragm is in at least the
neutral position, wherein the second axis is generally
perpendicular to the first axis; and wherein the flag is biased in
the first position and movement of the flag from the first position
to the second position is actuated in response to the diaphragm
being deflected a selected amount from the neutral position into
the first chamber and the pin being removed from the tab
assembly.
15. The indicator of claim 14 wherein the calibration spring is a
compression spring.
16. The indicator of claim 15 wherein the base includes a
foundation and a tap, wherein the tap includes an inlet defining a
recess in the tap, and the calibration spring is disposed with the
recess.
17. The indicator of claim 15 wherein the reset spring is a
compression spring.
18. The indicator of claim 15 wherein the guide plate includes
structures adapted to space-apart the main surface of the guide
plate from a base portion of the cover.
19. An indicator for signaling restricted flow of a fluid through a
filter, the indicator comprising: a chamber at least partly defined
by a diaphragm adapted for movement along a first axis in response
to movement of the fluid; and means, responsive to movement of the
diaphragm a predetermined distance along the first axis, for moving
a flag along a second axis from a first position to a second
position indicative of a restricted flow condition, with the second
axis generally orthogonal to the first axis.
20. The indicator of claim 19: wherein the diaphragm comprises a
stiff inner disk and a compliant outer ring portion, with the outer
ring portion including a pin generally parallel to the first axis;
and wherein the means for moving the flag is responsive to movement
of the pin a predetermined distance to move the indicator from the
first position to the second position.
21. The indicator of claim 19, wherein the indicator includes a
cover and wherein the means for moving the flag from the first
position to the second position moves a portion of the flag outside
and away from the cover.
22. The indicator of claim 21, wherein the cover has an exterior
opening, and wherein the means for moving the flag moves a portion
of the flag through the opening from the first position to the
second position, wherein a portion of the flag is outside the cover
in the second position.
23. A method of signaling restricted flow of a fluid through a
filter, the method comprising: moving at least a portion of a
diaphragm along a first axis in response to movement of the fluid;
and in response to movement of the portion of the diaphragm a
predetermined distance along the first axis, moving an indicator
flag along a second axis from a first position to a second
position, with the second axis generally orthogonal to the first
axis and the second position indicative of a restricted flow
condition.
24. The method of claim 23, wherein moving the portion of the
diaphragm along a first axis in response to movement of the fluid,
comprises: moving a pin in response to movement of the fluid,
wherein the pin is attached to the diaphragm.
25. The method of claim 23, wherein moving the indicator flag along
a second axis from the first position to the second position,
comprises moving a portion of the flag through a hole from an
interior of an indicator to an exterior of the indicator.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/040,913, entitled "FLUID FLOW RESTRICTION
INDICATOR," filed on Jan. 21, 2005, and incorporated by reference
herein in its entirety.
BACKGROUND
[0002] The present disclosure is directed to an indicator for
restricted fluid flow. More specifically, the present disclosure is
directed to a visible indicator for a filter system that provides a
signal when fluid flow through a filter is undesirably
restricted.
[0003] Many systems include a filtered fluid intake in order to
operate, and an example of such a system is an internal combustion
engine. The internal combustion engine includes a filtered air
intake that supplies filtered air for combustion to the cylinders.
The filter can become clogged or restricted with particulates.
Subsequently, airflow to the cylinders becomes restricted, which
can negatively impact the performance of the engine. These
performance degradations are not always immediately noticeable to
the user. Taking a filter assembly apart to inspect it is often
tedious. Also, a user often is not able to visually determine
whether the filter is sufficiently clogged to create degradation in
performance. According, there is a need for a device to indicate
when a fluid filter is undesirably restricted.
[0004] Several types of indicators for restricted fluid flow are
known. Some devices are relatively expensive real-time pressure
indicators. Often these real-time pressure indicators reset
themselves when the engine is turned off and there is no flow of
air in the intake. These devices are useful when the user of the
engines monitors the condition of the engine while the engine is
turned on. But such indicators do not provide an indication to a
service person that is maintaining or repairing the engine when the
engine is turned off.
[0005] One device directed to providing a visual indication of
restricted air low even after a compressor is turned off is
described in U.S. Pat. No. 5,616,157. The device includes a movable
ball separating two chambers. A first chamber is in communication
with the filtered airflow, and a second chamber is in communication
with the ambient atmosphere. As pressure drops in the first chamber
as a result of a restricted airflow, the ball is drawn into the
first chamber. After the ball has moved a threshold amount, the
ball releases an indicator flag that remains released after the
compressor has been turned off or restarted.
[0006] There is a continuing need, however, to provide a relatively
inexpensive, responsive, and accurate indicator for restricted
fluid flow that maintains the alert after the fluid flow has
stopped.
SUMMARY
[0007] The present disclosure is directed to a relatively
inexpensive visible indicator for a filter system that provides a
signal when fluid flow through the filter is undesirably restricted
and maintains the signal after the system is turned off. The
indicator is responsive and accurate, and can be formed as a
relatively low-profile device to be suitable for a wide variety of
systems and applications.
[0008] In particular, the disclosure is directed to an indicator
suitable for signaling restricted flow of a fluid through a filter
mounted in a filter assembly. The indicator includes a housing
having an inner cavity. A deflectable diaphragm is disposed within
the housing and separates the inner cavity into first and second
chambers with a generally fluid-tight seal. The first chamber is
adapted to be in fluid communication with the filter assembly, and
the diaphragm is deflectable from a neutral position in response to
applied pressures within the first and second chambers. A tab
assembly is included in the indicator opposite the diaphragm from
the first chamber. The tab assembly includes a hole. The tab
assembly also includes a flag moveable along a first axis from a
first position wherein the flag is within the housing and a second
position wherein the flag extends from the housing. A pin is
operably coupled to the diaphragm and protrudes along a second axis
from the diaphragm into the hole and through the tab assembly when
the diaphragm is in at least the neutral position. The second axis
is nonparallel to the first axis. Movement of the flag from the
first position to the second position is actuated in response to
the diaphragm being deflected a selected amount from the neutral
position into the first chamber and the pin being removed from the
tab assembly.
[0009] The indicator includes several advantages, and a few of the
advantages are mentioned here. For example, the indicator can be
easily manufactured to include low-cost polymeric parts. The design
of the indicator can provide for a larger diaphragm, which is more
accurate and responsive than other examples of the related art.
Also, the first and second axis operation described above provides
for a lower profile device than some of the examples of the related
art, enabling the indicator to be used in tight spaces and in a
variety of systems and applications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic view of an environment of the present
disclosure.
[0011] FIGS. 2A and 2B are schematic views of an indicator of the
present disclosure.
[0012] FIG. 3 is an exploded view of a particular example of the
indicator of FIGS. 2A and 2B.
[0013] FIG. 4 shows a partial cutaway side view of a portion of the
particular example of FIG. 3.
[0014] FIGS. 5A, 5B and 5C shows perspective views of three
examples of the diaphragm operably coupled to the pin suitable for
use in the example of FIG. 3.
[0015] FIG. 6 shows an exploded perspective view of a selected
portion of the indicator in the example of FIG. 3.
[0016] FIG. 7 shows a second embodiment of a component in the
portion of FIG. 6 in the example of FIG. 3.
DESCRIPTION
[0017] This disclosure relates to an indicator for restricted fluid
flow. The disclosure, including the figures, describes the
indicator with reference to a several illustrative examples. For
example, the disclosure proceeds with respect to an airflow
indicator used with an internal combustion engine, as described
below. However, it should be noted that the present invention could
be implemented in other system or with other fluids, as well. The
present invention is described with respect to the airflow
indicator for illustrative purposes only. Also, the disclosure
includes particular examples of the indicator, but by no means is
the disclosure limited to the examples below. Other examples are
contemplated and are mentioned below or are otherwise imaginable to
someone skilled in the art. The scope of the invention is not
limited to the few examples, i.e., the described embodiments of the
invention. Rather, the scope of the invention is defined by
reference to the appended claims. Changes can be made to the
examples, including alternative designs not disclosed, and still be
within the scope of the claims.
[0018] FIG. 1 is a schematic view of a system 20 having a filtered
fluid intake. The system 20 includes a filter assembly 21 and other
operative components 26. The filter assembly 21 includes a fluid
filter 24. Fluid 22 enters the system 20 and is passed through the
fluid filter 24. Filtered fluid 25 is then passed through the
filter assembly 21 to the operative components 26. An indicator 28
is disposed in the system 20 so as to be in fluid communication
with the filtered fluid 25 in the filter assembly 21. In one
example, the system 20 is an internal combustion engine. Air is
passed through an air filter, and filtered air is supplied to the
cylinders of the internal combustion engine. The indicator 28 is
disposed in the system to be in fluid communication with the
filtered air flowing to the cylinders. As the filter 24 becomes
dirty or is otherwise clogged with particulates, fluid flow is
restricted to the operative components 26. Based on the restricted
flow, the indicator 28 inferentially senses the filter is clogged
and provides a signal to an operator.
[0019] FIGS. 2A and 2B are schematic views of the indicator 28. The
indicator 28 includes housing 30 having an inner cavity 32. A
deflectable diaphragm 34 is disposed within the housing 30 and
separates the inner cavity 32 into a first chamber 36 and a second
chamber 38. The diaphragm 34 provides a generally fluid-tight seal
between the chambers 36, 38. "Generally fluid-tight" refers to a
seal that has a leakage rate low enough to not interfere with the
operation of the diaphragm and the indicator. The first chamber 36
is adapted to be in fluid communication with the filter assembly
21, as indicated above. In one example of the internal combustion
engine application, the second chamber is in fluid communication
with the ambient atmosphere. FIG. 2A shows the diaphragm 34 in a
neutral position. The diaphragm 34 is deflectable from the neutral
position in response to applied fluid pressures within the first
and second chambers 36, 38. The diaphragm 34 is also operably
coupled to a pin 40 that extends into the second chamber 38 in the
example. The indicator 28 also includes a tab assembly 42 disposed
within the second chamber 38 in the example. The tab assembly 42
has a hole 44 adapted to receive the pin 40. The tab assembly
includes a flag 46 moveable along a first axis 48. FIG. 2A shows
the flag 46 in a first position where the flag is disposed within
the housing 30. In FIG. 2B, the flag 46 is in a second position
where the flag 46 extends from the housing 30.
[0020] FIGS. 2A and 2B illustrate how the flag 46 moves from the
first position to the second position. In FIG. 2A, the pin 40
protrudes along a second axis 49 from the diaphragm 34 into the
hole 44 and through the tab assembly 42 when the diaphragm is in at
least the neutral position. The second axis 49 is nonparallel to
the first axis 48, and in the example the axes 48, 49 are generally
orthogonal to one another. As fluid pressure in the first chamber
36 is decreased relative to the pressure in the second chamber 38,
the diaphragm 34 is urged into the first chamber 36 and away from
the neutral position 34a. When the differential pressure in the
chambers 36, 38 has surpassed a threshold or selected amount, the
flag 46 is actuated and moves into the second position. In the
example, the deflected diaphragm removes the pin 40 from the hole
in the tab assembly 42, and the biased flag 46 is actuated to be in
the second position. In the example, the flag 46 remains in the
second position until the operator resets the indicator 20.
[0021] FIG. 3 shows one example of the indicator 28. The example
indicator 50 includes a base 52 that is adapted to be coupled with
a cover 54 to form an internal cavity. A deflectable diaphragm 56
is disposed within the internal cavity and against internal edges
of the base 52. A first chamber is formed between the diaphragm 56
and base 52, and a second chamber is formed between the diaphragm
56 and cover 54. A calibration spring 58 is disposed within the
first chamber and acts between the base 52 and diaphragm 56. The
diaphragm is operably coupled to a pin 60 that extends into the
second chamber. A tab assembly 62 is disposed within the second
chamber and includes a reset spring 64 and a flag 66. The flag 66
includes a hole 68 that is adapted to mate with the pin 60 when the
flag 66 is in the first position. The reset spring 64 biases the
flag 66 and urges the flag 66 through an opening 70 in the cover 54
to the second position when the pin 60 is removed from the hole 68.
A guide plate 72, in this example, is disposed in the second
chamber and provides a path of movement for flag 66 as it travels
between the first and second positions.
[0022] FIG. 4 shows a more detailed view of the components of the
example indicator 50 including the base 52 and calibration spring
58. The base 52 includes a foundation 74 connected with a tap 76.
The example shows the foundation 74 integrally formed with the tap
76, but other connections between the two are contemplated.
[0023] The tap 76 is adapted to attach the indicator 50 to the
filter assembly 21. In the example, the tap includes
circumferential ridges 77 that can create a fluid-tight seal
between the tap 76 and the filter assembly 21. For instance, the
tap 76 can be fit into a filter head of filter assembly on an
internal combustion engine. The circumferential ridges 77 form a
generally airtight seal with the filter assembly and no grommet is
needed. The tap can also be adapted to fit with any number of
filter assemblies, and include such features as pitched threads,
extensions with ridged lips (to connect to a filter hose), or the
like, to provide a generally fluid-tight seal with the selected
filter assembly. The tap 76 also includes an inlet 80 that leads
into the interior of the base 52. An elongate tube 81 that extends
into and concentrically within the tap forming a recess 82 defines
the inlet 80. The recess 82 is used to house the calibration spring
58. When the base 52 is coupled to a filter assembly, the inlet is
in fluid communication with the filter assembly and the first
chamber.
[0024] The calibration spring 58 provides low-pressure calibration
of the diaphragm 56. The spring 58 provides a holding force to
prevent deflection of the diaphragm 56. When the fluid pressure is
sufficiently low in the first chamber relative to the pressure in
the second chamber, the spring 58 is designed to compress and to
allow the pin 60 to release the flag 66. In the example, the spring
58 is an hourglass-shaped compression spring to reduce the
likelihood of buckling. Preferably, the spring includes a resonant
frequency outside of the operating range of the system 10. In the
example where the spring 58 is used with an internal combustion
engine, the resonant frequency is chosen to be outside the range of
500 Hz to 6000 Hz.
[0025] The foundation 74 is preferably pan-shaped, or
"birdbath-like," as indicated in the figures where the foundation
74 is wider than the tap 76. The exterior of the foundation 74 can
be constructed to include angularly spaced-apart ribs 75 to add
rigidity to the base 52 and to support the indicator 50 on a filter
head of a filter assembly, or the like. The example includes an
interior lip 84 and inlet tip 85 positioned to prevent
over-deflection of the diaphragm 56 that may cause damage to the
indicator 50. The pan-shaped feature of the foundation 74 is
advantageous in that it permits the use of diaphragm having a
relatively large surface area as compared to the size of the
indicator 50. The large surface area of the diaphragm 52 provides
for a more responsive diaphragm 52 and for more accurate deflection
of the diaphragm 52.
[0026] FIGS. 5A, 5B and 5C show three different examples of
diaphragms operably coupled to a pin that are suitable for use with
the example indicator 50. The first example diaphragm 52a, shown in
FIG. 5A, includes a generally compliant diaphragm member 152a and a
generally stiff protector disk 186a with pin 160a. The diaphragm
member 152a has a diameter large enough to fit across the
foundation 74 and provide a generally fluid-tight seal in the first
chamber around the edges of the diaphragm 152a. The protector disk
186a has a diameter that is smaller than the diameter of the
diaphragm member 152a and permits the edges of the diaphragm member
152a to deflect into the first chamber. The protector disk 186a is
disposed between the diaphragm member 152a and the calibration
spring 58, and provides a suitable surface to act against the
spring 58 and protect the diaphragm member 152a from tearing. The
pin 160a fits through a hole 188 in the diaphragm member 152a to
extend into the second chamber and engage the tab assembly 42. The
pin 160a fits into the hole 188 so as to still provide a low enough
fluid leakage rate to permit the indicator 50 to operate correctly.
In the example indicated, the disk 86a and the diaphragm 52 are not
otherwise attached to each other in diaphragm 52a.
[0027] The second example, shown in FIG. 5B, includes a diaphragm
member 52b having a relatively stiff inner disk 186b with pin 160b
and a relatively compliant outer ring 152b attached to each other
to form a single piece component. The compliant outer ring 152b is
wide enough to permit a flexible seal throughout the full stroke of
deflection and intended temperature range of the indicator 50. The
stiff inner disk 186b obviates the need for the protector disk 186a
in the two-piece diaphragm-pin shown above in FIG. 5A. The
diaphragm member 52b is manufactured to form a generally
fluid-tight seal between the inner disk 186b and the outer ring
152b.
[0028] The third example, shown in FIG. 5C, includes a diaphragm
52c having a relatively compliant member 152c sandwiched between
two relatively stiff disks 186c, 188c. The disks 186c and 188c are
riveted together. Disk 186c is adapted to act against the
calibration spring 58. Disk 188c includes an integrally formed pin
160c adapted to actuate the tab assembly 62.
[0029] FIG. 6 shows a particular example of the guide plate 72 and
tab assembly 62. The tab assembly 62 includes the flag 66 and reset
spring 64. The guide plate 72 can be used to compress the diaphragm
52 against the foundation 74 to create the seal when the indicator
50 is assembled. The guide plate 72 includes a main surface 73. The
guide plate 72 in the example provides structures to define a path
of movement for the flag 66. The guide plate also can provide a
surface against which the reset spring 64 can be coiled. The reset
spring 64 can also act against the cover 54. The illustrated guide
plate includes several case supports 89 that are used to maintain a
space between the guide plate 72 and the cover 54 to permit free
movement of the flag 66. Flag guides 91 limit lateral movement of
the flag 66. In this particular example, the guide plate 72 also
includes a reset spring support 92, which interfaces with the reset
spring 64. Height locks 94 are disposed around the periphery of the
guide plate 72 to maintain the main surface 73 of the guide plate
in a generally parallel plane with the base surface of the cover
54. The guide plate also includes a hole 95 through which the pin
60 can extend to engage the tab assembly 62. As it will be
understood, the structures to define the path of flag and reset
spring can also be included in the cover 54.
[0030] FIG. 6 shows one particular example of the tab assembly 62.
The flag 66 includes a major section 96 and a flange 98. The major
section 96 includes the hole 68 adapted to mate with the pin 60 to
keep the tab assembly 62 loaded in the first position. A flange 98
is included to reduce the amount of dust or other particles
entering into the internal cavity. The flange 98 also is pressed to
reset the indicator and move the flag 66 from the second position
back to the first position. In the example, the flag 66 extends
slightly through the opening 70 in the cover 54 and the flange 98
is disposed outside of the cover 54. The major section 96 is
generally disposed within the cover 54 when the tab assembly 62 is
in the first position. At least a portion of the major section 96
is exposed outside of the cover 54 when the tab assembly 62 is in
the second position.
[0031] The major section 96 can include several additional
components or features. For example, the major section 96 includes
skid ribs 97 that reduce surface contact between the flag 66 and
the guide plate 72 or, in some examples, the cover 54. The major
section 96 also includes a stop 99 that acts against one of the
structures of the guide plate (or cover), such as case supports 89,
to prevent the flag 66 from becoming dislodged from the indicator
50. In addition, the major section 96 can include an angled edge
101 to aid in locking guiding the pin 60 into the hole 68 when the
flag 66 is moved from the second position to the first position.
The major section 96 can also include a retainer portion 103, or
retainer edge, that engages the reset spring 64. In the particular
example, the reset spring is a torsion spring.
[0032] FIG. 7 shows another embodiment of the tab assembly 104. In
the embodiment, the reset spring 106 is a compression spring. The
flag 66 includes a bull nose 108 on the major section 96 and
opposite the flange 98 to interface with the spring 106. The bull
nose 108 can be inserted into the compression spring coil and an
interference fit is used to hold the spring in place.
[0033] The present invention has now been described with reference
to several embodiments. The foregoing detailed description and
examples have been given for clarity of understanding only. Those
skilled in the art will recognize that many changes can be made in
the described embodiments without departing from the scope and
spirit of the invention. Thus, the scope of the present invention
should not be limited to the exact details and structures described
in this disclosure, but rather by the appended claims and
equivalents.
* * * * *