U.S. patent number 3,611,220 [Application Number 05/056,592] was granted by the patent office on 1971-10-05 for condition-responsive monitor.
Invention is credited to Leslie J. Hoffman.
United States Patent |
3,611,220 |
Hoffman |
October 5, 1971 |
CONDITION-RESPONSIVE MONITOR
Abstract
A fluid pressure responsive device having two magnets with like
poles facing each other. A first magnet is mounted with a piston to
be movable in response to fluid pressure toward the other magnet to
thus cause the other magnet to move due to repelling forces of the
adjacent magnetic poles. A fixed armature, which may be adjustable,
is located in the field of influence of said poles to control the
repelling force which occurs between the magnets. The second magnet
may used to actuate an indicating device.
Inventors: |
Hoffman; Leslie J. (Orange,
CT) |
Family
ID: |
22005438 |
Appl.
No.: |
05/056,592 |
Filed: |
July 20, 1970 |
Current U.S.
Class: |
335/207; 200/82E;
200/82C; 200/82R |
Current CPC
Class: |
H01H
36/0073 (20130101) |
Current International
Class: |
H01H
36/00 (20060101); H01h 005/02 (); H01h
035/38 () |
Field of
Search: |
;335/205,207
;200/84C,81.9M,81.9R,82R,82C |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Interlock Switch; Keller, et al.; IBM Technical Disclosure
Bulletin; Vol. 10, No. 12, May 1968, page 1926, copy in
335-207..
|
Primary Examiner: Gilheany; Bernard A.
Assistant Examiner: Envall, Jr.; R. N.
Claims
I claim:
1. A condition-responsive monitor comprising, in combination:
a. a permanent master magnet,
b. means mounting the master magnet for movement in either of
opposite directions along a predetermined path of travel,
c. a drive device responsive to changes in a condition, for
shifting said permanent magnet in said path,
d. a permanent slave magnet,
e. means mounting the slave magnet for movement in either of
opposite directions along a predetermined path of travel adjoining
and noncoincidental with said first-mentioned path of travel,
f. said magnets being arranged with a pair of like poles directed
toward each other, thereby causing opposing forces to exist between
the magnets, which tend to separate the same,
g. a stationary magnetic armature piece disposed in the field of
influence of said like poles of the magnets, adjacent the paths of
travel of the same,
h. means biasing said master magnet to a position away from said
armature piece whereby it is movable toward the piece and against
said biasing means in response to changes in said condition,
i. said slave magnet being normally close to the armature piece,
dominating the magnetization thereof, and producing a flux therein
according to a given polarity, movement of the master magnet a
given distance toward the armature piece overcoming the magnetic
influence thereon by the slave magnet and driving the latter away
from the armature piece to a position relatively remote
therefrom.
2. A condition-responsive monitor as in claim 1, wherein:
a. said armature piece is disposed between said like poles of the
magnets,
b. said slave magnet being driven away from the armature piece with
a snap action when the master magnet overcomes the slave
magnetization of said piece as it moves toward the latter.
3. A condition-responsive monitor as in claim 1, wherein:
a. said armature piece is disposed adjacent the space between said
like poles of the magnets,
b. said slave magnet shifting slowly away from the armature piece
when the master magnet overcomes the slave magnetization of said
piece as it slowly moves toward the latter.
4. A condition-responsive monitor as in claim 1, wherein:
a. said drive device comprises a piston and cylinder,
b. said master magnet being connected to said piston to be shifted
thereby,
c. said cylinder having passages at opposite ends of the piston to
admit pressurized fluid.
5. A condition-responsive monitor as in claim 1, wherein:
a. said armature piece comprises a magnetic wire, and
b. means for adjustably positioning said wire, said means
comprising a screw carrying said wire in alignment with its axis
whereby turning of the screw either advances the wire into the
space between said like magnet poles or retracts the wire from said
space.
6. A condition-responsive monitor as in claim 1, wherein:
a. said armature piece comprises a strip of magnetic sheet metal,
and
b. means for adjustably positioning said strip, said means
comprising pivot means for enabling the strip to be swung into or
out of the space between said like magnet poles.
7. A condition-responsive monitor as in claim 1, and further
including:
a. a magnetic keeper disposed in the path of travel of the slave
magnet, for yieldably holding the latter in shifted position as
effected by the master magnet.
8. A condition-responsive monitor as in claim 1, and further
including:
a. a microswitch, and
b. means for actuating said switch in response to shifting of the
slave magnet by said master magnet.
9. A condition-responsive monitor as in claim 1, and further
including:
a. a reed switch having a magnetic actuator member,
b. said reed switch being disposed in the field of influence of the
slave magnet to be actuated thereby when the magnet is shifted by
the master magnet.
10. A condition-responsive monitor as in claim 1, and further
including:
a. a pilot light,
b. an energizing circuit for the pilot light, and
c. cooperable contacts controlling said energizing circuit and
actuated by said slave magnet when the latter is shifted by said
master magnet.
11. A condition-responsive monitor as in claim 1, and further
including:
a. pairs of electrical contacts respectively bridged by the slave
magnet when the latter is either close to said armature piece or
else shifted away therefrom.
12. A condition-responsive monitor as in claim 4, and further
including:
a. a tubular housing comprising said cylinder,
b. said master and slave magnets being axially shiftable in the
bore of the housing,
c. said biasing means comprising a coil spring in the housing bore
and encircling the master magnet.
Description
BACKGROUND
This invention relates to signalling or monitor devices, and more
particularly to condition-responsive or fluid pressure responsive
devices which employ magnetic members to effect a signal or
control.
Several prior signal or indicator devices intended to respond to
changes in fluid or liquid pressure utilized cylinder-and-piston
arrangements wherein the piston shifted as changes in fluid
pressure occurred on opposite sides of a filter. The piston was
connected with a permanent magnet, or alternatively it was
connected with a magnetic armature. In either case, an indicator
device was provided in the form of a permanent magnet which was
cooperable with the magnet or armature controlled by the piston. A
strong attractive force existed which maintained the indicator
device in a nonindicating condition, but if the piston and its
magnet or armature was shifted away from the signal magnet, the
latter being free for movement under the action of a biasing
spring, shifted to a different position whereby it constituted an
indication of the occurrence of a significant pressure change.
Other indicator or signal devices have members which experience a
gradual change, these members being mounted directly on a piston
which was shifted in response to changes in the fluid pressure.
These gradual-movement-type indicators did not give as definite or
distinct a signal as those in which an abrupt or snap action of the
indicator member occurred, when considering a clogged condition of
the filter element.
In other prior devices a pressure-actuated piston having a
permanent magnet was associated with a magnetic follower which
gradually shifted its position and which constituted the indication
as to the difference in pressures caused by clogging of the filter.
In still other devices a magnetic follower, which responded to a
magnet carried by a float, was employed as a liquid level
indicator, in connection with liquid containing vessels.
While these various prior devices have in general operated more or
less satisfactorily, they all had the common drawback or limitation
that the mode of operation was fixed and could not be altered to
suit different requirements of the user. For example, those
indicators which employed a snap action could not be readily
changed to provide a gradual or analog type of indication, and the
indicators which provided a gradual or analog type indication could
not be readily converted to provide a snap or definite "on-off"
type function. Moreover, the prior devices were in many instances
relatively large and complicated, having a great many parts. In
some cases the action of the parts was such that binding or
malfunctioning could occur, resulting in the device becoming
inoperative.
SUMMARY
The above drawbacks and disadvantages of prior condition-responsive
monitors or controls are obviated by the present invention, which
has for one object the provision of a novel and improved condition
or fluid-pressure responsive monitor which is capable of either a
snap action or else a gradual action of the indicator member, these
constituting either a distinct "on-off" type response or else an
analog or gradual type response, the arrangement being such that
the device is easily and quickly converted from one to the other
type of operation at the will of the user. This is accomplished by
a piston and cylinder arrangement wherein the piston carries a
small permanent magnet movable along a predetermined path of
travel, and wherein there is an adjoining path of travel of a
second or slave-type permanent magnet arranged to present a like
pole to the nearest pole of the piston-carried magnet. As a
consequence, magnetic repulsion exists between the magnets, tending
to separate the same. Adjacent the normal, nonindicating position
of the second or slave magnet is a fixed magnetic armature which is
normally influenced or magnetized by the slave magnet whereby it
tends to hold the latter in its nonindicating position. When the
piston-carried magnet is made to approach the armature and slave
magnet, it gradually overcomes the magnetic influence of the latter
on the fixed armature. Depending on the position of the armature,
the change or reversal in its magnetism as the piston-carried
magnet approaches, causes either a gradual shifting away of the
slave magnet or else a sudden snaplike shifting away of the latter.
The magnetic armature is adjustably mounted whereby it can be
interposed in the space between the two magnets to effect the snap
action of the slave magnet, or else removed somewhat from the space
between the magnets whereby there ensues a gradual, responsive
movement of the slave magnet as the piston-carried magnet is
advanced on the latter.
Other features and advantages of the invention reside in the
provision of a novel and improved, convertible monitor which
responds to changes in a condition as above set forth, wherein
relatively few parts are involved and wherein the construction is
extremely simple, thereby reducing the fabricating cost; the
provision of an improved convertible monitor of the kind indicated,
which may be easily and quickly changed at the will of the user,
from the gradual or analog type indication to the snap action type;
the provision of an improved condition-responsive monitor which
will readily actuate electrical switches such as microswitches,
reed switches and the like to effect electrical controls, so as to
illuminate a signal bulb for example; and the provision of an
improved monitor as described above, wherein a reset type operation
of the indicator may be readily had.
Still other features and advantages will hereinafter appear.
In the accompanying drawings illustrating several embodiments of
the invention:
FIG. 1 is a side elevational view of the improved convertible
condition-responsive monitor or control device as provided by the
invention, shown without seals.
FIG. 2 is an axial sectional view taken on the line 2--2 of FIG. 1,
but showing seals.
FIG. 3 is a top plan view of the device of FIGS. 1 and 2.
FIG. 4 is a fragmentary axial sectional view illustrating a
modified form of adjustable magnetic armature.
FIG. 5 is a view partly in top plan and partly in section, of the
monitor device of FIG. 4.
FIG. 6 is a view partly in axial section of a reset type monitor
device constituting another embodiment of the invention.
FIG. 7 is a partial axial sectional view of a convertible
condition-responsive control device having incorporated in it a
microswitch.
FIG. 8 is a partial axial sectional view of a convertible
condition-responsive device in conjunction with reed switches, to
actuate the latter.
FIG. 9 is a partial axial sectional view of a convertible device
provided with a signal or pilot light and cooperable switch
contacts, for providing an electrical control or electrically
operated signal.
FIG. 10 is a partial axial sectional view of a convertible
condition-responsive device having pairs of switch contacts, which
are made operative and inoperative as the device responds to
changing conditions.
FIG. 11 is a view partly in side elevation and partly in axial
section, illustrating a flange-mounting type of housing for the
device.
FIG. 12 is a side elevational view of a convertible monitor device
incorporated in a line-mounting type of housing.
Referring first to FIGS. 1-3, the present improved convertible
monitor device comprises a tubular housing 20 having a lower or
cylinder portion 22 in which there is reciprocatively carried a
piston 24 having a packing or rubber O-ring 26. At the outer end of
the cylinder 22 there is provided a snap ring 28 constituting a
stop for the piston, carried in an annular internal groove 30 in
the cylinder wall. Around its exterior, the cylinder 22 has a
packing or O-ring 32 adapted to constitute a seal when the piston
is inserted in a close-fitting bore of a supporting fitting. The
cylinder 22 has external screw threads 34 by which it can be
threaded into such fitting, and the housing 20 has a hexagonal
portion 36 adapted to accommodate a wrench, and also a packing or
O-ring 38 to effect a seal with the mouth of the fitting into which
the cylinder 22 is screwed.
Within the cylinder 22 there is a helical compression spring 40,
engaged at one end with the adjoining end surface of the piston 24
and at its other end with an annular spacer sleeve 42. As seen in
FIG. 2, the bore of the cylinder 22 constitutes in effect a blind
hole, in that the spacer sleeve 42 bottoms against a transverse
wall 44 of the housing 20.
The cylinder 24 has a shank portion 46 to which there is affixed a
permanent magnet 48 having north and south poles as indicated. In a
wall of the cylinder 22 there is provided a port 49 whereby fluid
pressure can be brought to bear against the upper or inner end
surface of the piston 24, to counteract fluid pressure bearing
against the bottom or outer end surface of the piston.
With such arrangement, pressure differential can be made to exist
with respect to the piston 24; when the pressure at the outer or
bottom end of the piston increases it will overcome the biasing
action of the coil spring 40, shifting the piston 24 upward in the
cylinder and likewise shifting upward the permanent magnet 48 which
is herein termed a "master magnet."
The housing 20 has a second bore 50 which is aligned with the bore
of the cylinder 22 but has no communication therewith. A domelike
or cup-shaped cover piece 52 of transparent material such as clear
plastic is carried in the upper bore 50 of the housing 20 so as to
enclose the bore, and a permanent slave magnet 54 is provided
within the cover 52, to be readily movable therein between a
nonindicating or lower position as illustrated in FIG. 2 and an
indicating or raised position wherein it occupies the upper portion
of the cover 52 and is clearly visible or in view.
In accordance with the present invention the slave magnet 54 has
its north pole lowermost, whereby it opposes the uppermost north
pole of the master magnet 48, thereby resulting in repulsion
between the magnets 48 and 54.
Also, disposed in the field of influence of the like north poles of
the magnets 48, 54 and adjacent the paths of travel of the same
there is a stationary magnetic armature piece 56 in the form of a
short length of magnetic or iron wire, said wire occupying a
transverse bore 58 in the housing 20 and being at one end carried
by an adjusting screw 60 which is threaded into the bore 58. As
seen in FIG. 2, the magnetic armature 56 is interposed in the space
between the north poles of the magnets 48, 54, and is located
closely adjacent the latter (slave) magnet when it occupies its
lowermost or nonindicating position. The master magnet 48 when in
its lower position (indicating that a relatively low fluid pressure
is being exerted at the bottom end of the piston 24) is relatively
remote from the armature 56.
With the parts in the positions illustrated in FIG. 2 the slave
magnet 54 dominates the magnetization of the armature piece 56,
producing a flux therein which tends to oppose the flux from the
north pole of the master magnet 48, Movement of the master magnet
48 a given distance upward toward the armature piece 56 will
overcome the magnetic influence thereon by the slave magnet 54,
eventually driving the latter away from the armature piece 56 and
upward, into the upper portion of the cover piece 52. Such upward
movement of the slave or indicator magnet 54 will be sudden, and
will have a snap characteristic if the armature wire 56 is
interposed in the space between the two magnets as shown in FIG. 2.
As presently understood, the magnetism of the north pole of the
master magnet 48 as the magnet is driven upward by the piston 24 in
responding to pressure changes, will overcome the magnetic
influence of the slave magnet 54 on the armature piece. Such
magnetic influence, prior to upward movement of the master magnet
42, has held the slave magnet 54 in its lower, nonindicating
position. However, the upward movement of the master magnet 48 in
overcoming the magnetism in the armature piece 56 as effected by
the slave magnet 54 will, in effect, reverse such magnetism whereby
in place of the attractive force between the armature piece and the
slave magnet 54 there will now abruptly be a repulsive force,
causing the slave magnet 52 to snap upward to a raised position in
the cover piece 52. At such time that the piston 24 is caused to
shift downward under the action of the spring 48 (due to removal of
the driving pressure from the bottom end of the piston 24) the
magnetic influence of the master magnet 48 on the armature piece 56
will become weakened, whereupon the weight of the slave magnet 54
and its magnetic attraction for the armature piece 56 will be
operative, resulting in the slave or indicator magnet 54 descending
to the nonindicating position of FIG. 2.
If the armature piece 56 is removed somewhat from between the north
poles of the magnets 48, 54, it will have a lesser effect in
holding the slave magnet 54 against movement as the master magnet
48 is caused to shift upward due to pressure changes on the piston
24. In consequence, the upward gradual movement of the master
magnet 48 will cause the slave magnet 54 to shift upward gradually
due to the repulsive forces existing between the magnets, such
repulsive forces being altered or effected to a much lesser extent
by the partially withdrawn armature piece 56. Accordingly, instead
of a snap action movement of the slave magnet 54 there will be a
gradual or analog type movement of such slave magnet.
It will be seen that the type of response or movement of the slave
magnet 54 can be easily converted by the user, in a simple manner,
by merely turning the adjusting screw 60 inward or outward, to
locate the armature piece 56 either closer to or further from the
space between the north poles of the opposing magnets 48, 54.
Another embodiment of the invention is illustrated in FIGS. 4 and
5. In this embodiment, components which are similar to those
already described have been given like numerals. In the embodiments
of FIGS. 4 and 5, in place of the axially or longitudinally movable
armature wire 56 there is provided a flat metal armature strip of
magnetic material, which is pivotally movable into and out of the
sphere of influence of the permanent magnets. As shown, the housing
20a has a horizontal slot or cut 62 in which there is disposed a
flat strip of sheet metal 64 constituting a magnetic armature
piece. The strip 64 has a pivot hole through which there extends a
pivot screw 66 threaded into the housing 20a. The exterior end of
the armature piece 64 has knurling or serrations 68 constituting a
finger grip, by which the strip may be readily shifted from its
fully operative, full line position illustrated in FIG. 5 to a
relatively inoperative broken line position indicated at 70 in FIG.
5. For the full line position of the armature piece 64 a snap
action of the slave magnet 54 will occur, whereas for the
inoperative position of the armature piece 64 indicated at 70 in
FIG. 5 a gradual or analog type movement of the slave magnet 54
will be had.
Another embodiment of the invention is illustrated in FIG. 6,
wherein like components already described have been given similar
characters. In FIG. 6, a cover piece 52b is provided in the bore 50
of the housing 20, said cover piece having a central opening in its
top wall 53b, through which there extends a stud 72 attached to an
movable with the slave magnet 54b. When the magnet 54b moves upward
in the cover piece 52b, the stud 72 will protrude from the top of
the cover piece. Against the underside of the top wall 53b of the
cover piece there is attached a magnetic keeper 74 in the form of a
steel annulus. As the slave magnet 54b moves upward to its raised
indicating position, the south pole thereof will attract the keeper
74 which is affixed to the cover piece 52b. Accordingly, the slave
magnet 54b will be retained in its raised indicating position after
having been shifted thereto in response to raising movement of the
master magnet 48. This arrangement constitutes a manual reset,
since it will be necessary for the user to depress the stud 72 so
as to reset the slave magnet 54 to its lower, nonindicating
position upon normal conditions being restored for the piston 24
and master magnet 48.
Yet another embodiment of the invention is illustrated in FIG. 7,
wherein the monitor device constitutes a control. Mounted on the
casing 20c is a microswitch 76 having an actuator arm 78 which is
disposed in the path of travel of the slave magnet 54. At the time
that the slave magnet 54 is shifted to it raised position, it will
actuate the arm 78 of the micro switch 76, causing an actuation of
the switch. The slave magnet 54 is shiftable in a vertical tubular
guide 80 carried by the housing of the microswitch 76.
Yet another embodiment of the invention is illustrated in FIG. 8,
wherein the housing 20d of the convertible monitor-control device
carries an enclosure 82 provided with an electrical connector
fitting 84. Within the enclosure 82 are reed switches 86 having
their lead wires connected to the connector fitting 84. The reed
switches 86 have magnetic elements 88 which are influenced by the
slave magnet 54. When the slave magnet is shifted to its raised
position, it will actuate the magnetic elements 88 from the reed
switches 86, either closing or opening the same as the case may
be.
Still another embodiment of the invention is illustrated in FIG. 9,
wherein the casing 20e is provided with an enclosure 90 on which
there is mounted a pilot light 92. An electrical circuit 94
including a battery 96 is provided for the pilot light, and
included in such circuit are electrical contacts 98 carried by a
circuit board 100. The contacts 98 are engageable by the upper
silvered surface 102 of the slave magnet 54e . When the magnet 54e
is shifted to a raised position, the silvered end surface 102
thereof will bridge the contacts 98, closing the circuit through
the lamp 92 and effecting its energization, thereby indicating that
the device has responded to a change in the conditions affecting
it.
Yet another embodiment of the invention is illustrated in FIG. 10,
wherein a casing 20f has an enclosure 104 carrying a connector
fitting 106. Within the enclosure 104, circuit boards 108 and 110
carry pairs of electrical contacts 112, 114 respectively which are
engageable respectively with the opposite silvered ends of a slave
magnet 54f. With the slave magnet 54f in the lower position
illustrated in FIG. 10, the contacts 114 are bridged, whereas with
the slave magnet in a raised position, the contacts 114 are not
bridged but instead the contacts 112 are bridged, thereby effecting
a circuit control for signalling or other equipment.
FIG. 11 indicates a flange mounting type housing 20g provided with
an annular mounting flange 116 in place of the screw thread
mounting 34 illustrated in FIGS. 1 and 2.
In FIG. 12, a housing 20h is illustrated, having a tubular fitting
portion 118 provided with internal end threads 120, 122 to receive
pipe fittings. A port 124 connects with one end portion of the
fitting section 118.
It will now be understood from the foregoing that I have provided a
novel and improved, readily convertible condition-responsive
monitor or control device which is especially simple in
construction, involving relatively few parts which may be
economically fabricated and assembled. The monitor may be quickly
converted from either a snap, on-off type of operation to a gradual
or analog type operation, by merely shifting a magnetic armature
piece between its operative and inoperative positions. The device
is effective and reliable in use, not subject to leakage or
malfunctioning, and is readily adaptable to monitor a variety of
different conditions wherein changes occur.
Variations and modifications are possible without departing from
the spirit of the invention.
* * * * *