U.S. patent number 3,760,733 [Application Number 05/240,569] was granted by the patent office on 1973-09-25 for self-leveling anti-disturbance device.
Invention is credited to Michael A. Marchiando.
United States Patent |
3,760,733 |
Marchiando |
September 25, 1973 |
SELF-LEVELING ANTI-DISTURBANCE DEVICE
Abstract
A normally open self-leveling anti-disturbance device which
includes a base having a generally hemispherical recess and closed
by a cover or lid provided with an outwardly directed hemispherical
protuberance for providing a hemispherical channel between the
cover and the base. The surface of the recess is provided with a
conducting coating which is divided into two separate electrical
circuits by etching. The circuits are physically isolated by a
continuous serpentine-like raised narrow rib which is formed with a
central insulated crack or depression. A metallic sphere is
disposed within the channel and is free to translate therein. When
the device is moved or disturbed the sphere will move across the
raised rib and in so doing will temporarily short the two circuits.
In its normal or undisturbed position the sphere will contact only
one of the circuits. There is also provided a plurality of bumpers
or deflectors to prevent the sphere from translating only within
the clear paths between the adjacent portions of the isolating
rib.
Inventors: |
Marchiando; Michael A.
(Richmond, IN) |
Family
ID: |
22907079 |
Appl.
No.: |
05/240,569 |
Filed: |
April 3, 1972 |
Current U.S.
Class: |
102/206;
200/61.45R |
Current CPC
Class: |
F42C
19/06 (20130101); F42C 11/007 (20130101) |
Current International
Class: |
F42C
19/06 (20060101); F42C 11/00 (20060101); F42C
19/00 (20060101); F42b 005/08 (); H01h
035/02 () |
Field of
Search: |
;102/7.2R,7.2A
;200/61.45R,61.45M,61.52 ;340/276 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Hanley; James M.
Claims
I claim:
1. A self-leveling anti-disturbance device comprising:
a. a base member of electrically insulating material having a
generally hemispherical recess formed therein, the surface of said
recess being formed with a continuous serpentine raised rib
extending entirely across said recess and having a
relatively-narrow central channel along its entire length, the
surface of said recess including said rib but excluding said
channel being coated with electrically conducting material to form
two separate conducting coatings isolated by said channel;
b. an electrical conductor connected to each of said coatings for
external connection therewith;
c. a cover formed with a hemispherical protuberance disposed across
and closing said base member to provide a hemispherical space
therebetween;
d. a sphere, having an electrically conducting coating, disposed in
said space for translation therein;
said channel having a width to permit said sphere to simultaneously
contact both of said conducting coatings, and the portions of said
surface adjacent to said channel being tapered upwardly toward said
channel; whereby said sphere will initially assume a rest position
in contact with only one of said coatings, and upon being disturbed
said sphere will move across said rib and channel and momentarily
short circuit said coatings.
2. The device as in claim 1, wherein adjacent portions of said
channel are spaced apart a distance greater than the diameter of
said sphere.
3. The device as in claim 2, further comprising a continuous
insulator strip disposed on the base of said channel.
4. The device as in claim 1, further comprising upstanding bumper
means for preventing said sphere, when in motion, from limiting its
translation to a path only along each coating instead of
transversely thereof.
5. The device as in claim 1, wherein said coatings are etched on
said surface.
Description
The invention described herein may be manufactured, used and
licensed by or for the Government for governmental purposes without
the payment to me of any royalty thereon.
BACKGROUND OF THE INVENTION
The present invention relates to an anti-disturbance device and
more particularly pertains to a self-leveling, anti-disturbance
device whose parameters and characteristics may be selectively
varied while retaining the inherent self-leveling feature.
In the field of anti-disturbance mechanisms, it has been the
general practice to employ standard anti-disturbance devices and to
physically level the device when it is actually employed or
emplanted. In general, for an anti-disturbance device to function
properly it must be leveled in order to provide a uniform overall
sensitivity. One such present component includes a gooseneck that
is incorporated into mine systems to provide for manual leveling to
compensate for a variety of terrains. These prior art devices
inherently add to the cost, to the time involved in the physical
emplacement and are sensitive to the extreme military environments
encountered in the field. Clearly, the number of moving parts of
these present devices all introduce operational limitations and
increase the cost of manufacture even when produced in large
quantities. Although it is desirable to use a normally open
circuited anti-disturbance apparatus, those now available do not in
general possess this unique property. The present invention fills
these apparent needs.
SUMMARY OF THE INVENTION
The general purpose of this invention is to provide an
anti-disturbance device that has all the advantages of similarly
employed prior art devices and has none of the above described
disadvantages. To attain this, the instant invention provides a
unique arrangement wherein a base having a hemispherical recess
whose surface has been coated or etched with a pair of conducting
areas separated a by serpentine narrow raised rib. The rib is
formed with an etched channel extending lengthwise thereof thus
electrically isolating the circuits. Raised deflectors are also
provided in order to prevent the metallic sphere disposed on the
surface from limiting its travel only along one circuit. The base
is closed across the hemispherical recess by a cover formed with a
hemispherical protuberance so that the sphere will be confined to
translate therebetween. In use the subject device is self-leveling
in that the sphere will assume an initial stationary position on
the hemispherical surface in contact with only one of the surfaces.
Upon being disturbed, the device will deflect from its initial
position and cause the sphere to translate over the rib and as it
passes over the depression it will momentarily and simultaneously
contact both circuits.
An object of this invention is to provide a simple, economical,
reliable and normally open circuited anti-disturbance device.
Another object is the provision of a self-leveling anti-disturbance
device characterized by its employment of only one moving part and
which is insensitive to extreme military environment.
Other objects and many of the attendant advantages of this
invention will be readily appreciated as the same becomes better
understood by reference to the following detailed description when
considered in connection with the accompanying drawings
wherein:
FIG. 1 is a cross-sectional view of an embodiment made in
accordance with the principle of this invention;
FIG. 2 is a view of the embodiment taken approximately along 2--2
of FIG. 1;
FIG. 3 is an enlarged cross-sectional view taken approximately
along 3--3 of FIG. 2;
FIG. 4 is a schematic diagram of an external electronic sensor
which may be employed in conjunction with the anti-disturbance
device of the present invention.
BRIEF DESCRIPTION OF A PREFERRED EMBODIMENT
In the illustrated embodiment of FIG. 1 an insulating base 10 is
formed with a central hemispherical recess or depression 11 which
is closed by a cover 12 that is provided with a complementary
generally hemispherical protuberance 13 thereby forming a
semi-spherical space 14 therebetween. Disposed for movement within
space 14 is a metallically surfaced contact sphere 15 which is free
to roll therein. The surface of the recess 11 has deposited thereon
an electrically conducting layer 16 which is physically divided
into a pair of conducting surfaces 17 and 18 forming separate
contact circuits. These circuits are best illustrated by way of
FIG. 2 where the circuits 17 and 18 are physically separated by a
serpentine channel 19 extending through the layer 16 and into the
base 10. An insulator strip 20 is disposed on the base of the
channel 19. A relatively simple structure would encompass a base 10
of a material that is an electrical insulator and whose surface is
coated with a conductive layer except along a line dividing the
circuits thus created. The spacing between adjacent linear sections
of the channel 19 is sufficient to permit the sphere to translate
therealong and thus create a path. If the entire hemispherical
recess surface where uniform or smooth the metallic sphere could
readily come to rest directly on the channel 19 and since the width
of the channel 19 is extremely narrow, the circuits would be short
circuited by the sphere. For this purpose, and to alleviate such a
problem, the area of the surface immediately adjacent the channel
19 is raised to form a longitudinally extending raised rib 21. The
raised rib, thus not only insures that the sphere will not position
itself directly on the channel 19 but, also that the sphere
requires a certain amount of energy to cross over the rib. In so
doing it momentarily shorts the two circuits. This energy is
provided by movement of the base or disturbance thereof. Upstanding
bumpers or deflectors 22 are formed in regions along the conductors
17 and 18 in order to prevent the sphere, when in motion, to limit
its translation to a path only along each conductor and not
transversely. Each circuit terminates in a connector strip 23 and
24 which is provided with a wire 25 and 26 or the like for external
connection to a control or switch means responsive to the momentary
shorting of the circuits.
FIG. 3 shows in detail a cross section of a typical raised rib 21
and the sphere 15 in two positions. As the sphere rolls under a
disturbing deflection along a path intermediate the adjacent
portions of the rib 21 it remains in contact with circuit 18. If it
has sufficient energy it will climb over the rib and at one point
along its motion it will assume a position of straddling the
channel 19 and simultaneously contact both circuits.
The particular circuit design configuration of the anti-disturbance
device described hereinabove provides relatively uniform
sensitivity over the full effective area. The following
calculations indicate that for the different or possible travel
paths of the sphere, the energy (deflection of the device) required
for activation varies but for all situations where the device would
be employed, this difference in sensitivity results in only a
negligible effect. The sensitivity of the specific embodiment can
be calculated as follows:
1. Since the anti-disturbance device must conform to Military
Specifications it is assumed that a stainless steel sphere (MS
19060 grade 10) having a diameter of 0.1875 inches and a density of
0.284 lbs/in.sup.3 so that its weight is:
wt = 0.5236(0.1875).sup.3 .times. 0.284 .times. 454 gm/1b = gms =
0.445 gms
by goldplating the sphere its total weight becomes:
wt = 0.4445 + 0.0321 = 0.4766 gms.
2. Assuming the raised strip is 0.002 inches high then the energy
required to lift the sphere over the strip in ergs (dyne/cm)
is:
Height .times. weight = energy
[0.002 .times. 2.54] .times. [0.4766 .times. 981] = 3.56 ergs.
3. Assuming the maximum clear distance 0.459 cms of travel for the
sphere and an activation tilt angle of 1.degree.19' then the energy
is:
[sin 1.degree.19' .times. 0.459] [0.4766] .times. 981 = 6.8
ergs.
It should be noted that for the highest or maximum sensitivity the
amount of energy for the sphere to travel over the 0.002 inch strip
is 3.56 ergs.
Since the anti-disturbance hereinbefore described is normally in
the open circuit condition an external electronic sensor as shown
in FIG. 4 can be employed in conjunction therewith. Upon activation
of the device which is effectively, the equivalent, of a switch 40,
transistor device 41 commences conducting and the other transistor
42 ceases conducting. This in sequence turns the silicon controlled
rectifier 43 "on" thus providing a signal for the indicator 44
which may be of the visual type. Analyzing the circuit it is
evident that the shorting of the anti-disturbance circuit need not
be a low resistance since any contact resistance encountered will
be insignificant with respect of the resistance of resistor 45 and
the input resistance of transistors 41 and 42.
I wish it to be understood that I do not desire to be limited to
the exact method and detail of construction described for obvious
modification will occur to persons skilled in the art.
* * * * *