Note: Descriptions are shown in the official language in which they were submitted.
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P~ESS-~T-ANY-POIN'l' SWITCIIIN~ DEVICE
The present invention is directed to a press-at-
any-point switching device, and more particularly, to a
press-at-any-point switching device which comprises an
electromagnetic wave generator and does not require direct
coupling to a power source or the unit which is actua-ted.
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Background of the Invention
i
Press-at-any-point switches have been designed for
a wide variety of applications. They have been utilized
as floor mats, in automobile seat cushions, on elongated
surfaces of potentially dangerous, heavy moving objects,
and in other applications where the use of a button or
other form of "single-point switch", such as a type used
for a conventional doorbell, would not be suitable.
Conventional press-at-any-point switches are typically
located on or partially recessed within a surface which
then defines an actuation zone. When pressure is applied
to or in the case of a normally closed switch, removed
from the actuation zone, a signal is relayed to a corltrol
mechanism, such as a motor. These conventional switches
are typically directly coupled to the control mechanism
via electrically conductive leads, i.e. wires, or some
other form of continuous conduit through which a signal is
transmitted.
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In certain applications, the installation of a
press-at-any-point switch, though highly desirable in a
specific actuation zone, can be prohibitively expensive
and can create other hazards. For example, in certain
industrial applications, the preferred actuation zone is
on the surface of the floor in a warehouse or
manufacturing facility. The use of conventional press-at-
any-point switches at these locations results in the
presence of exposed electrical conduits which thereby
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1 create an undesirable obstruc-tion to workers and
machinery, or necessitates the expense of installing the
electrical conduits in the flooring. In -the latter case,
if it becomes desirable to relocate the actua~ion zone, i-t
has been necessary with conventional press-at-any-point
switches to cut a new trencll in the concrete flooriny for
~ the relocation of the necessary electrical conduits. This
; procedure is expensive, very time consuming, and also
creates the danger that a worker will be injured during
the relocation.
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Furthermore, in certain applications it has been
desirable to locate the actuation zone of a press-at-any-
point switch outside the protective walls of a facility
but permanent placement at an exterior location is not
feasible in light of the risks of vandalism during time
periods in which the facility is closed.
It is, therefore, desirable to provide a press-at-
any-point switching device which is readily movable from
- one actuation zone to another without incurring the
expense, delay and other risks inherent in conventional
relocation procedures. It is further desirable to provide
a press-at-any-point switch which is sufficiently durable
to withstand the physical and chemical abuse of industrial
areas while providing ease in reloca-tion from one
actuation zone to another.
Summary of the Invention
3o
; The present invention is directed to a press-at-
any-point switching device which comprises a switching
element with a power source and an electromagnetic wave
generator such as a radio transmitter. The generated wave
is designed to be transmitted to a remote signal receiver
which is coupled to a conventional con-trol unit such as a
switch for an electric motor. Since the switching element
of the present invention comprises a signal generator,
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1 there is no need for cumbersome and possibly dangerous
signal conduits, e.g. electrical cables, which directly
couple the press-at-any-point switching device Wit}l the
desired control unit. Embodiments of the switching device
; 5 of the present invention may be readily transported
~i between different actuation zones without the expense,
delay and potential danger :inherent in the reloca-tion of
the electrical conduits of conventional press-at-any-point
switching devices described above.
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Brief Descriptions of the Drawin~s
Figure 1 is a cross-sectional view of one
embodiment of the present invention with sections removed.
Figure 2 is a cross-sectional view of the switching
device shown in Figure 1 along lines 2-2.
; Figure 3 is a top, perspective view of a set of
contacts shown in Figure 1.
Figure 4 is perspective end-view of the press-at-
any-point contacts shown in Figure 3.
Figure 5 is a perspective view of an alternative
embodiment of the present invention with sections
removed.
- Figure 6 is a cross-sectional view taken along
lines 6-6 of Figure 5.
Figure 7 is a partial, bottom perspective view of a
corner of the switching device illustrated in Figure 5
showing a battery access door.
Figure 8 is a cross-sectional view of another
embodiment of the present invention taken from a
perspective similar to that of Figure 6.
; Figure 9 is a perspective view, with sections
removed, of still another embodiment of the present
invention.
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1 De-tailed Description
: As used herein, the term "press-at-any-point" is
meant -to include switching elements which have an expanded
actuation zone and which can be actuated by the
application of or the removal of pressure a-t substantially
any point along the actua-tion zone which essentially
comprises one surface of the switch. In conformance with
its usage in the art, this term is meant ~o exclude
conventional contact switches such as those typically used
for doorbells wherein the actuation of a device requires
the application of pressure within a small, very specific
area, such as the pushing of a bu-tton.
According to several embodiments of the presen-t
invention, the press-at-any-point switchiny element is in
the form of a floor mat as illustrated in Figures 1 to 8.
In one preferred embodiment of the present invention
illustrated in Figures 5-8, the switching element is in
the form of a protected floor mat. In accordance with an
alternative embodiment, the switching element is in the
form of a elongated edge switch for use on a elongated
surface such as the edge of a moving objec-t.
With reference to Figure 1 which illustrates a
floor mat embodiment of the present invention with
sections removed, switching device 10 comprises a
protective outer casing having a top cover 21, bottom
cover 27 and side walls 25. The outer casing is
preferably formed of a wear-resistant moisture-resistant
material such as a rubber elastomer, polyvinyl chloride,
or polyurethane. The outer casing is also preferably
impermeable to dirt and other materials which may
adversely affect the operation of the switching device.
Top layer 21, as well as all other layers utilized in mat
lo, have at least a slight degree of flexibility which
will allow the entire protective mat 10 to conform to
floors or other mounting areas which are not perfectly
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1 flat. For example, it is preferable tha-t -the materials
utilized in a mat having dimensions of ~ ft. X 4 ft. x
inch allow the mat to be readily flexed at least about 5
and preferably a-t least about 20 without adversely
affecting the operation of the mat, where the angle is
defined as the angle between a flat floor on which one end
of the mat is placed and a tangent drawn along the
opposing bottom surface of the mat. Of course, it will be
appreciated by those skilled in -the art that the anyle of
flexibility will depend, in part, upon the dimensions of
the mat. Additionally, mat 10 is advantageously
~ sufficiently flexible so that pro-tective mat 10 can be
: placed over objects in the work area, such as a heavy
utility electrical cord, without causing continuous
actuation of the switches. Top layer 21 is formed of any
material which will withstand the environment in which -the
protective mat 10 will be used. For example, it will be
appreciated by those skilled in the art that certain
materials will have greater resistance to corrosion by
specific chemicals than other materials which might
otherwise be suitable.
One suitable material for the ou-ter casing is
- KOROSEAL manufactured by the Koroseal and Rubber Matting
Products Company of Akron, Ohio, a division of R.J.F.
International Corp. This particular elastomer has been
found to have a high resistance to wear, puncture and
cutting. Koroseal is also relatively easy to work with
and seal along its edges using sealing methods known in
the art, for example, heat sealing.
As shown in Figure 1, top layer 21 may also
comprise ribs 24 in order to provide skid resistance for
- people stepping on the mat. Ribs 24 also enhance the
; 35 drainage of liquids which may fall onto the mat and
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1 thereby increase the overall life of the mat. While -the
thickness of top layer 21 may vary for the particular
applications in which protective mat 10 will be used, it
has been found that the preferred thickness of upper layer
21 is at least about 1/16 inch and is more preferably
about 3/16 inch including the top ribs.
As shown in Figure 2, the casing may be formed of
two separate pieces having cu-t out portions which receive
the operative switching elements or, in a simpler version,
may simply comprise two substantially laminar sheets witl
sufficient overlap at the edges to permit the sealing of
the sheets. Those skilled in the art will appreciate that
various methods of sealing the differen-t portions of the
casing may be utilized. For example, R-F hea-t sealing may
be utilized when polyurethane or polyvinyl chloride
materials are used since R-F energy provides durable seals
which are relatively easy to form.
The interior side of top layer 21 may
advantageously be provided with a plurality of ridges 22
extending the width of the mat and disposed
perpendicularly to the longitudinal axes of the switching
elements. Ridges 22 are designed to concentrate the force
applied to top layer 21 to specific points on the contact
elements 30.
The operative elements of the switching device
include at least one and preferably a plurality of contact
members 30, a power source 40, and an electromagnetic wave
generator 50 having an antenna 55.
The electrical contacts may take any of various
forms known in the art wherein the application of, or
removal of, pressure from any point in the desired
actuation zone establishes or breaks an electrical
communication thereby.
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1 One type o~ electrical pressure-actuated swi-tch
which is suitable for many industrial applications is
shown in ~igures 1-~ wherein electrical pressure-~ctuate~
; switches 30 comprises electrical contacts 31 and 32
separated by insulating material 33. In order to
facilitate construction, insulating material may be formed
in the shape of a strip having grooves 34 on both sides as
shown in Figure 4. In this manner, one contact strip 32
may be disposed below the insulating grooves 3~ while the
other contact strip 31 may be disposed above the
- insulating groove 34. A non-conductive filamellt 35 is
preEerably wrapped around the electrical pressure-actuated
switch 30 in order to hold the elements of the switch 30
together. Switches 30 may be connected in parallel, as
shown in Figure 1, or in series via electrically
conductive wires. As shown in Figure 1, pressure-actua-ted
electrical switches 30 are connected to power source 40
and signal generator 50 via electrically-conductive
conduits 39. It will be appreciated by those skilled in
the art that other types of pressure-actuated electrical
switches may be utilized without departing from the scope
of the present invention.
For example, one or more normally-closed pressure-
actuated, press-at-any-point switches such as the types
disclosed in co-pending U.S. patent applicaion 472,710
filed January 31, 1990, which is hereby incorporated by
reference, may be used.
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The desired spacing of the pressure-actuated
switches will depend upon the specific application to
which the protective mat will be used. A spacing of about
1 1/4 to about 5 inches from the cen-ter of one electrical
switch to another is acceptable for many industrial
applications.
Those skilled in that art will appreciate that
signal generator 50 may be designed to generate an
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1 electromagnetic wave in response to a signal initiated at
pressure-actuated switching elements. The signal is
-transmitted via antenna 55 to a remote si~nal receiver.
Signal generator 50 may take several forms including any
type oE radio wave oscillator, an infra-red wave generator
or a micro-wave generator. If a radio-wave generator is
used, the present invention is not limi-ted to specific
frequencies or modulations.
Another embodiment o~E the present invention
comprises a puncture-resistant protective layer wherein
the switching elements are preferrably isolated from both
the environment and the puncture-resistant member. The
preferred form of this embodimen-t comprises an upper
moisture-reslstant layer, a puncture-resistant and/or
deformation-resistant protective layer disposed below the
top layer, a bladder disposed below the protective layer
and preferably attached to the upper layer so that the
protective layer is isolated Erom the environment, and a
switching chamber defined by the lower surface of the
bladder and a lower outer surface. In accordance wi-th
this embodiment of the present invention, the switching
element is protected from harmful matter such as moisture,
dirt, or corrosive chemicals which may be present in the
work area near the protective mat even if the mat is
subject to a blow from a sharp object which punctures the
top outer layer.
According to the embodiment of the present
~; 30 invention illustrated in Figs. 5-8, disposed below top
layer 110 is a puncture-resistant, and preferably
deformation-resistant protective layer 120 which disperses
forces applied to the mat. High, point-of-impac-t forces
applied by sharp tools or the like, are dispersed over
relatively wide areas in order to protect the portion of
mat 100 disposed below protective layer 120 from punc-ture.
~s used herein, the term "deformation" is used to mean
permanent deformation, i.e., a change in the shape of an
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l object UpOIl the application of a force wherein the object
does not return to the configuration it hacl before the
application of the force. As mentioned above, protective
layer 120 has su~ficient flexibility -to enable ben~ing o~
the entire protective mat 100 w~len the mat is not placed
on a perfectly level surface. Protec-tive layer 120 must
have a sufficient degree of flexibility so that if
protective mat 10 is placed on an uneven surface or a
surface containing a ridge, for example, a concrete floor
having a heavy electrical cord which runs under mat 100,
protective layer 120 permits the en-tire mat 100 to bend
without continuously actuating the pressure-actuated
element 160. Protective layer 120 must also have
sufficient resistance to permanent deformation SUCII that
if an object is dropped on protective mat 100, though -the
object may puncture top layer 110 and instantaneously
deform protective layer 120, protective layer 120 will not
stay in such deformed position so as to continuously
actuate a pressure-actuated switching element.
One method of measuring the suitability of a
material or combination of materials for use as protective
layer 120 is to measure the distance that a dent or groove
will protrude from the bottom surface of protective layer
120 after the application of an impact by a dart weighing
about 2 1/2 pounds, with a point having a diameter of
about 0.10 inches which is dropped from a still position
approximately 8 feet above the mat. In order to be
considered "deformation-resistant" in accordance with the
present invention, the permanent deformation of a
protective layer having a thickness of about 1/4 inch
subject to the preceding "Dart Test" will prsferably not
exceed about 0.050 inches and is most preferably less than
about 0.025 inches.
As used herein, the term "puncture-resistant" means
that the protective layer will not be punctured, i.e. such
that a hole passes entirely through the protective layer,
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1 when the layer is subjected to the "Dart Test" referenced
above but modified such that the dart is dropped from a
height of about 3 feet. It ~ill be appreciated by those
skilled in the art that light gauge metals, such as 1/16
inch thick spring steel, are not "puncture-resistant" as
that term is used herein.
While not necessary to the practice of the present
invention, as shown in Figure 1, protective layer 120 may
be advantageously sealed between top layer 110 and a
bladder layer 140.
The material or combination of materials used in
the construction of protective layer 120 are designed to
disperse a blow of a sharp object which may come in
contact with protective mat 10. Protective layer 120 may
be formed of a single material such as one or more layers
of a high impact-resis-tant polycarbonate e.g.
LEXAN/LEXGUARDTM made by General Electric, or may be
formed from layers of different materials such as a high-
impact resistant polycarbonate with a middle-layer of re-
enforcing material such as Kevlar.
In order to spread the force of an impact over as
wide an area as possible, it is preferable to have the
bottom or non-impact side of protective layer 120 to be
; generally smooth.
Disposed below protective layer 120 is a
hermetically-sealed switching chamber 160, shown in Eigure
6, defined by flexible, moisture-resistant bladder layer
140 and flexible, moisture-resistant bottom layer 180.
The top 141 of bladder layer 140 is preferably
substantially smooth in order to receive an impact from
protective layer 120 over as wide of an area as possible.
The bottom surface 142 of protective layer 140 preferably
comprises a number of ribs 143 which extend substantially
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1 from one end of swi-tching chamber 160 to the other end.
The advantages provided by ribs 1~3 are the same as those
provicled by ribs 22 of mat 10 descr:ibed above.
Bottom layer 180 has a top surface 1~1 and a bottom
surface 1~2. As shown in Figure 6, bottom surface 182 of
bottom layer 1~0 is advantageously provided with ribs 183
which will allow water and other fluids -to drain below
protective mat 100. Therefore, if protective mat 100 is
intended for use in an area subject to liquid spills,
protective mat 100 will not impede the drainage of the
spilled li~uid into an already existing draill nor will it
cause fluids which might shorten the useful life of
protective ma-t 100 to collect next to protective mat 100.
As illustrated in Figure 5, protective mat 100 also
comprises a power source 190 and a signal generator 193
having an antenna 195. The operation and actuation of a
signal may be the same as described above with reference
,~ 20 to mat 10.
Figure 8 illustrates an al-ternative embodiment of a
protective mat of the present invention wherein a
plurality of protective layers 220, 221 are utilized in
order to provide protection to the operative switching
elements.
Figure 7 illustrates a battery access door 99 which
may be provided to give access to the power source, as
well as the signal generator. Depending upon the intended
use of the switching device, the battery access door 99
may be sealed with a replaceable, moisture-resistant
sealer such as silicone.
It will also be appreciated that, in accordance
with the present invention, a switching chamber may be
. divided into a number of switching zones for several
reasons. In certain applications, it may be desirable to
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have one portion of the switching element provide a
signal to one control clevice while another portion ol~ the
switching chamber actuates another device. In some
instances, it may also be desirable to provide a
5 corresponding plurality of protective layers (not shown)
which each extend over only a portion of a bladder layer,
instead of a sinyle protective layer 120 as shown in
Figure 5. As an aIternative, several isolated switchiny
chambers can be provided.
As shown above in the embodiment of the present
- invention disclosed in Figures 1-4, if the pressure-
actuated device comprises a plurality o~ elec-trical
pressure-actuated switches 130, the switches 130 are
15 preferably arranged perpendicular to the ribs 143 of
bladder layer 1~0. In this manner, the force applied by
each rib 143 at the point of contact between rib 143 and
pressure-actuated electrical switch 130 is more
concentra-ted than if the ribs 143 extended parallel to
20 switches 130. It will be appreciated by those skilled in
the art, that the actuation of switches 130 only requires
contact at a single point along the top or bo-ttom of the
switches 130, as opposed to a complete contact alony the
entire length of the switch 130.
Those skilled in the art will also appreciate that
alternative pressure-actuated switching devices may be
utilized in place o~ the illustrated electrically-
conductive contacts. For example, a pneumatically-
30 operated switching device could be coupled with a signalgenerator.
The present invention may be practiced with a
pressure-actuated switching device taking many shapes.
35 For example, a single pressure-actuated switching element
such as switch 300 illustrated in Figure g may be
electrically connected with an electromagnetic wave
generator 350 and a power source 340. Such a switch
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1 and/or the signal generator may be enclosed within a
flexible protective housing 320. The press at any point
switch 300 is suitable for placement on the edye of a
movable object such as the bottom of a garage door or
another piece of equipment any may be fastened to the
desired actuation surface if desired.
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