Note: Descriptions are shown in the official language in which they were submitted.
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41IT-2526
ELECTRICAL CURRENT INDICATING METER
CROSS--REFERENCE TO RELATED APPLICATIONS
The subject application is related to the
Canadian application of Edward F. Scannell and Ed~ard D.
5 Orth, entitled "Shielded Electrical Current Indicating
Meter", Serial No. 3~5,789, filed February 15, 1980
and assigned to the same assignee as the subject application.
This application also relates to the Canadian Application
of William J. Schultz and Carl F. Van Bennekom, entitled
10 "Magnetic System for Electrical Current Indicating Meter",
Serial No. 345,791, filed February 15, 1980 and assigned
to the same assignee as the subject application~
This application further relates to the Canadian
Application of William J. Schultz and Carl Fo Van Bennekom,
15 entitled "Pivot Insert Method and Article", Serial No.
346,732, filed February 29, 1980, and assigned to the
same assignee as the subject application.
Further, this application relates to the Canadian
Application of Edward F. Scannell, entitled "Adjustable
20 Spring Regulator for Setting Indicating Instrument Pointer",
Serial No. 345,790, filed February 15, 1980 and assigned
to the same assignee as the subject application.
Still further this application relates to the Canadian
Application of Edward F. Scannell and Donald E. Rogers
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entitled "Means for Adjusting the Zero Point Setting of
a Meter", Serial No. 339,991, filed November 16, 1970
and assigned to the same assignee as the subject
application.
The invention of this disclosure relates to small
electrical current indicating meters of the general
type disclosed in U.S. patents 3r621,393 - Pignolet,
dated November 16, 1971, and 4,064,457 - Boreas, dated
December 20, 1977.
This invention comprises a new and improved,
symmetrical construction for small sized electrical
current indicating meters comprising the combination
of a unitary frame member with concentrically arranged
components which provide greater versatility and
multiple functions in the assembly and performance
of the meter and savings in the manufacture thereof.
It is a primary object of this invention to
provide a new construction for electrical current
indicating meters which is more versatile and flexible
in manufacture and service.
It is also an object of this invention to provide
a small compact electrical current indicating meter
constructed of integrated composite parts of units
which simplify manufacture and assembly, and render
the meter more economical and versatile in service.
It is a further object of this invention to
provide an improved construction for electrical current
indicating meters which renders it feasible and advan-
tageous to use dielectric organic polymeric materials
to form integrated or unitary composite parts or units
which lend greater versatility and flexibility in
production and assembly of such meters, and a reduction
in the number of parts or components and in turn costs.
It is a still further object of this invention
to provide a compact electrical current indicating
meter construction which advantageously lends itself
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to the use of structural parts or components molded
in a single or unitary ur.it from dielectric organic
polymeric materials, and therefore the attainment of
many benefits and savings, including: obviating the need
for separate dielectric insulating devices or means,
such as blocks or washers, to electrically isolate units
or circuits; enabling ultrasonic heading or staking to
join and secure parts, and thereby eliminate hardware
components such as fasteners; and permitting the
integral molding in situ of screw threads for attaching
adjustable components rather than the use of a separate
component such as an inserted tapped busing.
FIGURE l iS a perspective view of the electrical
current indicating meter of this invention;
FIGURE 2 iS a partial bottom view of the meter of
FIGURE l;
FIGURE 3 iS a partiall~ exploded view showing
the assemblage of the primary current indicating mechanism
of the meter and the means for mounting same in a housing;
and
FIGURE 4 is a fully exploded view of the primary
current indicating mechanism.
Referring to the drawings, FIGURE 1 shows a meter
product 10 of a preferred embodiment of this invention,
comprising a housing 12, provided with terminals 14
and 14' for making electrical connections with the
meter, and a visual scale 16 in association with a
pointer 18 for indicating the measured quantity of
electrical current determined by the meter.
The primary electrical current measuring mechanism,
or the basic units therefor of a preferred embodiment
of the meter construction of this invention, as shown
in detail in FIGURES 3 and 4, comprises a pair of
spaced apart, parallel flux plates 20 and 22 formed
from a suitably magnetic flux conducting metal or "soft"
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41IT-2526
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magnetic material such as iron or soft steel; a frame
member 24 formed as a unitary body molded from a non-
magnetic organic polymeric material; and a rotor
assembly 26.
Spaced apart, parallel flux plates 20 and 22 of
the preferred embodiment are of a generally flat,
ellipsoidal or disk-like configuration to easily
accommodate completely within their intermediate
perimeter one or more magnet units of various size or
capacity. Each rounded or oval flux plate 20 and 22 is
provided with a central orifice 28 and 30, respectively,
and a pair of outward projecting perforated ears 32 -
32' and 34' - 34' for mounting in a predetermined spaced
apart, parallel relationship with respect to each other,
and the other components of the meter.
Unitary frame member 24 is provided with a pair of
generally parallel studs 36 - 36' which are arranged
to align with and pass through the perforations in ears
32 - 32' and 34 - 34' of plates 20 and 22, respectively,
and thereby join and secure these components together
in an appropriate spaced apart parallel relationship.
Frame 24 is additionally preferably provided with a
pair of laterally or outwardly extending arms 38 - 38',
also perforated, for the mounting, such as with bolts,
of the primary current measuring mechanism within a
meter housing 12, or in an appropriate electrical device.
Also, frame 24 is provided with a central orifice 40
having molded therein suitable threading for receiving
a screw adjustable jewel bearing 42, and an integrally
molded or formed washer-like element 44 comprising a
projecting portion or boss having a circumferential
groove 46 thereabout for cooperation with a regulator
or adjusting means.
In accordance with this invention frame member 24
is molded as a unitary or integral body unit from a
high strength and temperature resistant dielectric
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41IT-2526
organic polymeric material, for example, a glass filled
blend of polyphenylene oxide and polystyrene, such as
General Electric Company's NORYLTM plastic. Such a frame
member and composition provides adequate structural
integrity and heat resistance to retain the mechanical
strength of its features such as molded or cut screw
threads, over a long service life and/or under adverse
conditions such as extensive exposure to high temperatures
and vibrations.
Rotor assembly 26 comprises an electromagnetic coil
48 which is of apt dimensions and configuration to
closely surrounded the ellipsoidal flux plate 20, a
pointer 18, and a pair of oppositely extending pivot
shafts or staffs 50 and 52 for mounting the overall
assembly 26 for rotational movement back and forth in an
arcuate path in ~he same plane as the flux plates 20 and
22. Pivots 50 and 52 are affixed to the rotor assembly
at a location thereon approximately central to the
length of the coil, and they respectively extend to and
rest in screw adjusting jewel bearings 42 and 54.
Bearing 42, as noted above, is threaded into frame member
24, and bearing 54 is threaded into a bushing 56 inserted
in the central orifice 30 of flux plate 22 which is
mounted on studs 36 - 36' the furthest from frame member
24, is parallel relationship with plate 20.
As shown in the drawings, in assembly, flux plate
20 is mounted closest to frame member 24 with the
frame member studs 36 - 36' passing through the perfora-
tions or openings in its projecting ears 32 - 32', and
flux plate 22 is similarly mounted parallel thereto
farthest from frame member 24 with studs, 36 - 36' also
passing through the perforations or openings of its
projecting ears 34 - 34'. Spacing posts or cylinders
58 - 58' can be used surrounding studs 36 - 36' and
positioned intermediate the parallel flux plates 20 and
22 to provide a predetermined spacing between the plates.
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Thus, any required or desired distance between the pair of
parallel flux plates 20 and 22 can readily be unerringly
achieved in assembly and positively maintained, or changed,
by the use of spacing posts of appropriate dimensions or
length. spacing posts 58 - 58' can be composed either of
magnetic flux conducting material such as ferrous metal,
or a nonmagnetic material such as a dielectric plastic,
depending upon the particular requirements or needs of
the magnetic flux system or circuit employed.
One or more magnet bodies, including permanent
magnets, such as the pair of counterposed permanent
magnets 60 - 60' illustrated, are positioned inter-
mediate the flux plates 20 and 22 residing on the
inner surface of flux plate 22 which is farthest from
frame member 24, and there secured by any suitable
means such as an adhesive. The number, configuration
and positioning of magnetS or magnet bodies should be
arranged to attain optimum magnetic flux forces or
strengths circulating through the flux system or
circuit comprising flux conducting plates 20 and 22,
and in turn past the electromagnetic coil 48 of rotor
member 26. In a preferred embodiment two arcuate
permanent magnets 60 and 60' are symmetrically deployed
on each side of the central coil pivot point or
pivot 52 with their polarity aptly aligned to produce a
uniform flux field or fields of suitable direction(s)
and intensity through the system. For example, the two
magnets aligned with opposite polarity of N facing S
are arranged on opposite sides of the pivot point of
pivot shaft 52 extending from the rotor assembly 26 to
the bearing 54 affixed to flux plate 22 furthest
from the frame member 24.
The spacing between parallel flux plates 20 and
22 is such as to provide a sufficient air gap or space
between the magnet or magnets 60 positioned on the
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41IT-2526
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inner surface of flux plate 22, and the inner surface
of flux plate 20 to aptly accommodate the free rotational
movement of coil 48, or the intervening portion thereof,
through the gap without contacting either the magnets of
the flux plates.
Upper and lower control springs 62 and 64 bear
against the rotor assembly 26 to appropriately bias its
alignment and pointer 18 in relation to the scale 16,
and to provide suitable torque resistance to rotary
movement of the rotor assembly when induced by electro-
magnetic forces resulting from current flow through the
coil, and thereafter return the rotor assembly and its
pointer when the forces are terminated.
A regulator arm 66, which connects with washer
element 44 of frame 24, is provided to adjust or
synchronize the terminal position or setting of the
rotor assembly 26 with its pointers 18 at a given
indice, such as zero of the scale 16.
Also, an adjustable spring regulator disc 68 can
be included to change the tension of the spring 64.
Electrical conductors for carrying current to
the electrically sensitive or activated meter com-
ponents, such as the electromagnetic coil, for measure-
ment, are provided by insulated wires 70 and 72 shown
in FIGURE 3. In a preferred embodiment, wires 70 and
72, respectively, connect terminals 14 and 14' with flux
plate 22 and with regulator arm 66 which in turn makes
electrical contact with the electromagnetic coil 48
through upper control spring 62.
The electrical current indicating and measuring
meter mechanism or apparatus of this invention, as will
be apparent to those skilled in this art, operates on
the D'Arsonval principle which is well known and
understood in the art, for instance, note the disclosure
of U.S. patents No. 3,621,393 - Pignolet dated November
16~ 1971, and 4,064,457 - Boreas dated December 20, 1977.
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41IT-2526
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However, the distinctive construction for the
meter of this invention places the pivotal position
and pivot means for the rotor assembly substantially
intermediate the length of the electromagnetic coil
and generally concentric with the flux plates, and it
also provides for several magnet units symmetrically
arranged around the pivotal position and the coil.
Thus, the end portions of the electromagnetic coil
extend approximately equally outward from the central
pivotal position in opposite directions with each
portion of the coil projecting over or into the area
of influence or force of the flux field of one of the
two, or more, magnetic units. Then, by providing
the two, or multiples of two, so located magnet units
arranged with polarities opposite each other, their
respective magnetic flux inducing deflective force or
influence acting upon each portion of the coil on opposite
sides of the pivot point is in effect additive or
accumulative with respect to the rotational force upon
the rotatable electromagnetic coil and the rotor as-
sembly carrying the same. In other words, the
oppositely directed forces are so deployed on each side
of the central pivotal point of the rotatable coil and
symmetrical assembly so as to cooperate and thereby
effectively double the rotating deflective force upon
the coil, as well as balance the torque and mechanical
pressures on the pivot structure.
The distinctive construction and arrangement of
components of the electrical current indicating meter
Of this invention, including the unitary frame member
o~ a dielectric body in combination with the elipsoidal
flux plates mounted thereby and the concentrically
positioned magnetic coil of the rotor assembly and
symmetrical arrangement of such components, including
the magnet bodies, wherein the frame member provides a
central bearing for the coil pivot, provides a meter
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41IT~2526
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device with many advantages and improvements. For
instance, the combination including the frame member
provides a maximum distance within the meter housing
for the spacing of the magnetic coil pivot bearing
which contributes to greater stability or freedom
from play in the pointer arm. Also, the frame member
construction in the overall combination provides for
a single unitary molded unit to perform many functions
including a supporting structure or frame for the simple
and unerring assembly, positioning and mounting of the
the components in their precise arrangement with respect
to each other and with the housing. Moreover, the frame
can be integrally molded as a single body comprising
portions which itself perform many functions in addition
to providing an economical component to produce.
