Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a battery exhaustion indi-
cator.
All primary batteries generate electricity by chemical
action and in all primary batteries the chemical action and the
production of electricity stops when one of the electrodes is
exhausted. Where batteries are essential to the operation of
electrical apparatus such as telephones, signals and the like
they must be replaced or repaired before they cease to function.
For this reason, it is important to know the extent to which the
electrode is used up, and to know the time when new electrodes
must be furnished or when the entire primary battery is to be
replaced.
The present invention provides a rugged mechanical
battery life indicator, responsive to the dimensions of one or
both of the electrodes. If the battery is a carbon zinc combin-
ation, only the zinc electrode is sensed and its thickness
indicated. The indicator means is positioned at the top of the
container for convenience of the user.
One of the features of the invention is the ability to
use the exhaustion indicator with battery containers that are
opaque. The indicators can also be used with electrolytes that
are not transparent.
According to the invention there is provided a battery
exhaustion indicator for use with a primary battery having at
least one electrode which is depleted with use, comprising: a
fluid tight case, a scale carried by the case, at least one
sensing arm, resiliently urged against a major face of the
battery electrode which is depleted with use; said sensing arm
comprises a means for contacting a large average space on the
said electrode; a rotatable shaft secured to the sensing arm, a
resilient means coupled to the rotatable shaft for urging the
sensing arm against the electrode major face and an elongated
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pointer coupled to said arm and having a free movable end
adjacent to the scale for indicating the thickness of the de-
pleted electrode.
Additional details of the invention will be disclosed
in the following description, taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 is a perspective view partly in phantom of a
battery showing two partially depleted electrodes and two
exhaustion indicators.
Figure 2 is a top view of the battery showing the
calibrated scales in greater detail.
Figure 3 is a cross sectional view, taken along line
3-3 of Figure 4, showing additional details of the resilient
means.
Figure 4 is a cross sectional view, taken along line
4-4 of Figure 2.
Figure 5 is a side view of an alternate form of
sensing arm, terminated by a flat disk.
Figure 6 is a side view of another alternate form of
sensing arm, terminated by four additional arms.
Figure 7 is a side view of still another alternate
form of sensing arm, terminated by a woven wire mesh.
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DESCRIPTION OF THE PREFERRED EMBODDMENT
Figures 1 through 4 show the deta;ls of the exhaustion
indicator mounted in a fluid tight battery container. The con-
tainer 10 includes the usual base 11, sides 12~ and a top cover
13 which supports two leadin conductors 14 and two calibrated
scales 15. A detachable vent 16 may be positioned on the top
cover 13 but this is not always necessary. Inside the container
two electrodes 17, 18 are positioned at opposite sides of the
container and an electrolyte fills the remainder of the space
within the container. The two electrodes are held in place by
four mounting strips (2~ which are conductors made of a
material such as copper.
As mentioned above, the electrodes 17, 18 may be made
of various materials, the zinc-carbon electrodes being only two
of the many materials available for this purpose. The invention
does not depend upon any particular composition of the electrodes
but only upon electrodes which are depleted by use.
The exhaustion indicator for each of the electrodes
includes a sensing arm 21 secured to a horizontal rotatable shaft
22. Shaft 22 is journalled in holes in the mounting strips 20
and is secured or otherwise coupled to an elongated indicating
pointer 23 which extends slightly above the top cover 13. The
ends of the pointer 23 may be tapered to increase the accuracy
of the measurement. The pointer ends are positioned adjacent to
the transparent scales 15, provided with graduations and indicia
which give a measure of the movement of the sensing arms 21. The
calibrated scales 15 are preferably mounted above the top surface
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of the cover 13 and above the top surface of the electrolyte as
shown in Figures 1 and 4.
In order to maintain the sensing arms against the
electrode surfaees, the indicating pointers 23 are, extended
below the shafts 22 and terminated in a hook 23A. The hooks 23A
are joined by a resilient means 24, shown in Figures 1, 3, and 4
as a helical tension spring. The spring urges the sensing arms
21 into a firm contact with their associates electrodes 17 ard 18.
The operation of the exhaustion indicator is obvious
from the figures and the above description. The indicator rods
are initially set to indicate a reading on the scale, representing
an unused state. As the battery is used and the electrode materi~
depleted, the sensing arm 21 and the indicating pointers 23 m~ e
away from their original position, indicating the extent of the
depleted electrode. As more electrical current is produced, the
depletion of the electrode continues, and the sensing arms are
moved farther from their original position. The replacement time
is signaled when the indicating pointers 23 approach zero on the
scale.
The sensing rods 21, as shown in Figures 1, 3, and 4,
are short cylindrical insulator rods with a minimum area pressing
on the electrode. It is well known that the depletion area is
usually irregular and may be formed with hollows and bulges due
to a varying chemical composition of the electrode. In order to
sense an average depletion distance, the sensing arms can be
fitted with a number of alternate contact terminations as shown
in Figures 5, 6, and 7. The contact means 25 (Figure 5) is a
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flat disk, secured to the end of sensing a.rm 21 by a flexible
joint 26. The contact means 27 (Figure 6) is a plurality of
cross arms, mounted on joint 26 and bearing against a large area
of the electrode. The contact means 28 is a web of insulator
fibers 28, arranged to sense a large average space while permit-
ting a large percentage of the current to flow from the sensed
space through the woven fibers.