Note: Descriptions are shown in the official language in which they were submitted.
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PASSIVE SAFETY SYSTEM WITH A DIRECTION SENSING EXIT ZONE
FOR USE IN A MOBILE STORAGE SYSTEM
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates to a mobile storage system, and more particularly to a
passive safety arrangement for use in a mobile storage system.
A mobile storage system typically consists of a series of storage units that
are
movable on rails or the like toward and away from each other. Movement of the
storage
units is controlled so as to selectively create an aisle between an adjacent
pair of storage
units. When an aisle is created, a user enters the aisle to access an area of
one or both of
the storage units that form the aisle, such as to remove an object from one or
more of the
storage units or to place an object on or in one or more of the storage units.
Mobile
storage systems of this type are commonly available from a number of different
manufacturers, including Spacesaver Corporation of Fort Atkinson, Wisconsin.
A number of safety systems have been developed so as to ensure that an aisle
is
empty before the pair of storage units forming the aisle are closed in order
to create an
aisle between a different pair of storage units. In a typical configuration of
a passive
safety system, a series of cross-aisle sensors are positioned at spaced-apart
locations
throughout the length of each storage unit in an adjacent pair of storage
units. The cross-
aisle sensors are typically uniformly spaced a selected distance apart, e.g.
on twelve inch
centers, and act to sense the presence of a person or object in the aisle. The
cross-aisle
sensors are typically in the form of light beam emitters and receivers. The
presence of a
person or object in the path of one of the light beams prevents the light beam
from
reaching the receiver, which provides a signal to a controller that is
interpreted to indicate
the presence of a person or object in the aisle. In this manner, the
controller is responsive
to the signals so as to ensure that the adjacent storage units are not closed
until the aisle
between the storage units is clear of persons or objects.
In addition, prior art passive safety systems have employed a quadrature
sensor at
each entry or access point between adjacent mobile storage units. Each
quadrature sensor
typically includes a pair of light beams, which are sequentially blocked as a
person or
object enters or exits an aisle to indicate the direction of movement of a
person or object
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into or out of the aisle. The quadrature sensor is typically placed at
approximately knee
level, which ensures that a person is not able to step over the light beams of
the quadrature
sensor when entering or exiting the aisle. The controller is responsive to
signals from the
both the quadrature sensors and the cross-aisle sensors, to ensure that
adjacent storage
units are not closed until it is determined that the aisle between the storage
units clear and
that every person or object that has entered that aisle has also exited the
aisle.
While a passive safety system having the above-identified components is
reliable
and functions well, it involves certain drawbacks. For example, the cross-
aisle sensors
and the quadrature sensors are mounted to each storage unit in different
locations, i.e. the
cross-aisle sensors are low and close to the floor whereas the quadrature
sensors are
elevated above the floor. This requires separate mounting of the housings and
other
components of the different sensors. In addition, the cross-aisle sensors and
the
quadrature sensors require separate wiring. As a result, the number of parts
involved in
this configuration, in combination with the resulting assembly time and labor
costs,
increases the overall cost associated with manufacture of the storage units.
It is an object of the present invention to provide an improved passive safety
system for use in a mobile storage system, which simplifies the construction
and
installation of cross-aisle sensors and quadrature sensors in the mobile
storage units. It is
another object of the invention to provide such an improved passive safety
system which
provides reliability in detecting the presence of persons or objects between
adjacent
mobile storage units and also senses direction of movement of persons or
objects into or
out of the aisle. A still further object of the invention is to provide a
simplified and
reliable method of sensing the presence of a person or object between adjacent
mobile
storage units and direction of movement of a person or object into or out of
the aisle.
In accordance with a first aspect of the invention, a mobile storage system
includes
a number of storage units supported by a supporting surface, including at
least a first
storage unit that is movable toward and away from a second storage unit by
operation of a
drive arrangement to selectively create an aisle between the first and second
storage units,
in which the aisle is accessible from an end area. A sensing system detects
the presence of
persons or objects in the aisle and also detects the direction of movement of
persons or
objects into or out of the aisle. The sensing system includes a number of exit
zone
emitters and receivers located adjacent an end area of the first and second
storage units
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that defines the end area of the aisle, and a number of inner emitters and
receivers located
along an inner area of the first and second storage units inwardly of the end
area. The exit
zone emitters and receivers and the inner emitters and receivers are located
at generally
the same elevation adjacent and above the supporting surface. In one form,
each of the
storage units includes a carriage and a storage member secured to the
carriage. The
carriage is movable relative to the supporting surface, and the exit zone
emitters and
receivers and the inner emitters and receivers are located on the carriage.
In accordance with another aspect of the invention, a mobile storage system
includes presence and direction sensing means carried by the storage units for
detecting
the presence of persons or objects in the aisle and for detecting the
direction of movement
of persons or objects into or out of the aisle. The presence and direction
sensing means
includes an end sensing section, or exit zone, located adjacent at least an
end area of the
first and second storage units that defines the end area of the aisle, and an
interior sensing
section located inwardly of the end area. The end sensing section and the
interior sensing
section are interconnected with each storage unit via a sensor housing carried
by the
storage unit and located above the supporting surface. Each storage unit
includes a
carriage and a storage member secured to the carriage, and the sensor housing
is located
on the carriage. The end sensing section and the interior sensing section are
located at
generally the same elevation adjacent and above the supporting surface.
Another aspect of the invention contemplates a method of operating a mobile
storage system that includes adjacent first and second storage units supported
by a
supporting surface. This aspect of the invention includes detecting the
location of a person
or object within an aisle between the first and second storage units adjacent
an end area of
the first and second storage units and along an inner area of the first and
second storage
units inwardly of the end area. The act of detecting the location of a person
or object
within an aisle is carried out so as to detect both the presence of the person
or object and
the direction of movement of the person or object, both of which are carried
out at
generally the same elevation adjacent and above the supporting surface,
preferably using a
series of emitters and receivers carried by the storage unit.
The invention also contemplates an improvement in a carriage for supporting a
storage member for use in a mobile storage system in which the carriage is
movable by
operation of a drive arrangement relative to a supporting surface. In
accordance with this
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aspect of the invention, the carriage includes an outwardly facing side area
that is adapted
to face an aisle formed in the mobile storage system when the carriage is
positioned in
spaced apart relationship relative to an adjacent storage member. A presence
and direction
detecting sensing system is interconnected with the outwardly facing side
area, and
includes a sensor housing having a series of exit zone sensors located
adjacent at least an
end area of the carriage, and a series of inner sensors located along at least
an intermediate
area of carriage inwardly of the end area. The sensor housing and the sensors
are
configured relative to the carriage so as to be at generally the same
elevation adjacent and
above the supporting surface when the carriage is positioned on the supporting
surface. A
power supply and communication arrangement is interconnected with the sensor
housing,
and is configured to supply power to the sensors and to communicate signals
from the
sensors to a controller.
The invention also contemplates a method of constructing a carriage for
supporting
a storage member for use in a mobile storage system, substantially in
accordance with the
foregoing summary.
Various other features, objects and advantages of the invention will be made
apparent from the following description taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate the best mode presently contemplated of carrying out
the
invention.
In the drawings:
Fig. 1 is an isometric view of a representative pair of adjacent mobile
storage units, such as are incorporated in a mobile storage system having a
number of such
units, incorporating the passive safety system exit zone in accordance with
the present
invention;
Fig. 2 is a top plan view of the mobile storage units of Fig. 1;
Fig. 3 is an elevation view of one of the mobile storage units, with
reference to line 3-3 of Fig. 1;
Fig. 4 is a partial enlarged elevation view, with reference to line 4-4 of
Fig.
3, showing components of the passive safety system exit zone in accordance
with the
present invention;
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Fig. 5 is a section view taken along line 5-5 of Fig. 4;
Fig. 6 is a rear elevation view, with reference to line 6-6 of Fig. 5, showing
components of a power supply system for the components of the passive safety
system
including the exit zone;
Fig. 7 is a partial exploded isometric view showing a portion of the power
supply system of Fig. 6;
Fig. 8 is a view similar to Fig. 1, showing the location and configuration of
cross-aisle sensors and quadrature sensors in a prior art installation; and
Fig. 9 is a top plan view of the mobile storage units of Fig. 8, showing the
positions of the cross-aisle sensors and the quadrature sensors.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Fig. 1, a mobile storage system includes a series of mobile
storage
units, such as are shown at 20. While Fig. I illustrates a pair of mobile
storage units 20, it
is understood that the mobile storage system may include any desired number of
storage
units, and that the storage units may have any desired length, width, height
and
configuration. One or both of mobile storage units 20 may be moved both toward
and
away from the other, typically by means of wheels or rollers associated with
the storage
units 20 that are movable on rails or tracks mounted in a floor or other
supporting surface,
in a manner as is known. The storage units may be movable using any
satisfactory known
type of drive system, such as an electric motor-powered drive system.
In a typical construction, each mobile storage unit 20 may be in the form of a
carriage 22 to which one or more storage members 24 are mounted. As is known,
storage
members 24 may be in the form of shelving units, cabinets, etc. Each carriage
22 typically
includes spaced apart sets of wheels that are movable on the rails or tracks
mounted in the
floor or other supporting surface. Each carriage 22 also includes a drive
arrangement,
which typically includes an electric motor and a drive system interposed
between the
motor output and the wheels for providing movement of the storage unit 20.
Representatively, each storage unit 20 may include an end panel 26 that
includes an
actuator pad 28 that is operated by a user to selectively operative the motor
or other drive
arrangement in order to move the storage unit 20 in a selected direction. In
this manner,
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the adjacent storage units 20 can be selectively moved apart to create an
aisle 30
therebetween, and can be selectively moved together to eliminate aisle 30.
A sensor system 32 is located at the lower extent of each storage unit 20. In
the
illustrated embodiment, sensor system 32 is provided along a side surface
defined by
carriage 22, which extends generally throughout the entire length of carriage
22. The
sensor system 32 of each storage unit 20 interacts with a facing sensor system
32 of the
adjacent storage unit 20 and is operable to detect the presence of objects or
persons within
aisle 30 in order to ensure that aisle 30 is clear before storage units 20 are
moved together.
The facing sensor systems 32 also are operable to detect the direction of
movement of
persons or objects into or out of the ends of the aisle 30. Each sensor system
32 is
interconnected with a controller associated with the storage unit 20, to
ensure that the
motor or other drive arrangement for the storage unit 20 cannot be operated to
move a
storage unit 20 in a direction to close an aisle 30 if the aisle 30 is not
clear of persons or
objects, in a known manner.
Each sensor system 32 includes a pair of outer or exit zone sensor sections 34
and
an inner or interior sensor section 36. The interior sensor section 36
includes a series of
evenly spaced interior cross-aisle sensors 38 that are adapted to cooperate
with the interior
cross-aisle sensors 38 of the facing interior sensor section 36 in order to
detect the
presence of a person or object within aisle 30. Interior sensors 38 are spaced
apart a
predetermined distance, such as on 12 inch centers, throughout the length of
the inner
sensor section 34 of each storage unit 20.
Each exit zone sensor section 34 includes a series of exit zone sensors 40,
which
cooperate with the facing exit zone sensors 40 to detect the presence of a
person or object
in the exit area of the aisle 30. Each exit zone sensor section 34 further
includes a pair of
quadrature sensors 42 at the end area of the storage unit 20 at the point at
which a user or
object enters or exits the aisle 30. Quadrature sensors 42 function to sense
the direction at
which a person or object moves relative to aisle 30, i.e. into the aisle 30 or
out of the aisle
30.
Representatively, the sensors 38, 40 and 42 may be conventional photocell-type
sensors that both emit a light beam that extends across aisle 30 and receive a
light beam
from a sensor on the opposite side of aisle 30. That is to say, sensors 38, 40
and 42 are
photo emitters and receivers, in a known manner, and provide a signal to a
controller or
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the like indicative of whether an emitted light beam is blocked so as to
prevent it from
being received by the facing receiver in order to indicate the presence of a
person or object
within aisle 30 between the emitter and the receiver.
As noted above, sensors 38 of interior sensor section 36 are spaced apart a
predetermined distance, e.g. on 12 inch centers. Exit zone sensors 40 are
spaced apart a
distance that is less than the spacing of sensors 38 of interior sensor
section 36.
Representatively, the spacing of exit zone sensors 40 may be 6 to 7 inches,
and exit zone
sensor section 34 has a sufficient length and number of exit zone sensors 40
to ensure that
a person cannot step over the exit zone sensor section 34 when entering or
exiting the aisle
30. The length of exit zone sensor section 34 may representatively be in the
range of 24
inches to 36 inches, although a length of 28 inches has been found to provide
satisfactory
operation.
Quadrature sensors 42 are spaced very closely together, e.g. 1 inch apart, and
are
sequentially blocked as a person or object enters or exits aisle 30 so as to
provide an
indication as to the direction of movement of the person or object into or out
of the aisle
30.
As shown in Figs. 3-5, each sensor system 32 is secured to a side wall 44 of
one of
the carriages 22. The sensors 38, 40, 42 are interconnected with the carriage
side wall 44
by means of a sensor housing 46, which extends throughout the majority of the
length of
carriage 22. Representatively, sensor housing 46 may include a flange 48 that
is employed
to secure sensor housing 46 to the outer surface of carriage side wall 44.
Sensor housing
46 may also include a series of walls including a bottom wall 50, a top wall
52 and a side
wall 54, which cooperate with carriage side wal144 to form a closed passage
56. Sensor
housing 46 is located on carriage side wall 44 so as to be spaced a
predetermined vertical
distance above a supporting surface S, which may be a floor or the like,
relative to which
the storage unit 20 is movable. Representatively, sensor housing 46 may be
located such
that passage 56 is located at an elevation of approximately 2 to 6 inches
above supporting
surface S.
Fig. 5 illustrates one of the sensors 40 that is secured to carriage side wall
44 via
sensor housing 46. It is understood that the illustration and description of
sensor 40
applies equally to the manner in which sensors 38 and 42 are secured to
carriage side wall
44 via sensor housing 46.
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As shown in Fig. 5, each sensor 40 includes an emitter 58 and a receiver 60.
Side
wall 54 of sensor housing 46 includes an opening 62 in alignment with emitter
58, which
enables a light beam from emitter 58 to exit the interior of sensor housing 46
and to
project across aisle 30. Receiver 60 includes an outer head 64 and an inner
mounting
section 66, which extends through an opening in sensor housing side wall 54.
As shown in Fig. 6, the passage 56 formed by each sensor housing 46 is adapted
to
receive the internal components of the sensors 38, 40, 42 as well as a power
and
communication distribution system for supplying electrical power to the
sensors 38, 40, 42
and for communicating signals from the sensors 38, 40, 42 to the controller.
Each of
sensors 38, 40 and 42 is mounted to a sensor mounting board 68, which includes
a pair of
depending ears 70 that are engageable within slots 72 formed in sensor housing
bottom
wall 50. Each sensor mounting board 68 further includes a pair of power and
communication connectors 74, and suitable conductors for providing electrical
power and
communication to the components of sensors 38, 40, 42 that are secured to
board 68. A
wire harness 76 is located between each set of adjacent sensor mounting boards
68 and
includes connectors 78 at its ends, each of which is engageable with one of
power and
communication connectors 74 for supplying power and communication to the
sensor
mounting board 68. At the endmost sensor mounting board 68, a power supply and
communication input/output is engaged with the endmost connector 74 for
supplying
power and communication to the system, which is then transferred between
adjacent
sensor mounting boards 68 by the wire harnesses 76.
Fig. 7 illustrates an endmost sensor mounting board 68, which includes
connections 80 for a pair of emitters 58 associated with quadrature sensors
42. The
remaining sensor mounting boards 68 include single connections 80 for a single
emitter 58
such as is associated with sensors 38 and 40.
In operation, the sensor systems 32 function as follows in order to detect the
presence of a person or object within aisle 30 and to detect the direction of
movement of a
person or object into or out of aisle 30. As a person or object enters aisle
30, sensors 42 at
the end of aisle 30 detect the inward movement of the person or object into
the aisle 30 by
means of the sensors 42 being sequentially blocked when the aisle 30 is
entered. In the
event a person steps over sensors 42, the person's foot will then obstruct one
of the closely
spaced exit zone sensors 40, and the next step of the user also obstructs an
inner one of the
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exit zone sensors 40 so that the sequence of obstruction of sensors 40
provides an
indication as to the direction of movement of the person into the aisle 30.
When the
person or object is in the aisle 30, certain of the interior sensors 38 or the
exit zone sensors
40 are obstructed, to provide an indication that the person or object remains
within the
aisle 30. As the person or object exits the aisle 30, the person or object
sequentially
obstructs the exit zone sensors 40 to again provide an indication as to the
direction of
movement of the person or object out of the aisle 30. Quadrature sensors 42
provide a
redundant indication as to movement of the person out of the aisle. Again,
however, in the
event the person steps over quadrature sensors 42, the sequential blocking of
the exit zone
sensors 40 as the user exits the aisle provides an indication that the user is
exiting the aisle.
When all of the sensors 38, 40 and 42 are clear, typically for a predetermined
time period,
the storage units 20 can be moved together to close aisle 30.
The present invention utilizes a logic system incorporated into the controller
that
enables the controller to continuously monitor the position of a person or
object in an
aisle, and to compare the present position of the person or object with the
position at a
predetermined earlier time, which enables the controller to sense the
direction of
movement of the person or object in the aisle. While the direction of movement
of the
person or object in the aisle can be sensed at any location along the length
of the aisle, the
exit zone and quadrature sensors enable the controller to determine direction
of movement
with a relatively high degree of precision at the exit zone of the aisle.
Figs. 8 and 9 illustrate a prior art sensor system for mobile storage units,
such as
20'. In this configuration, a series of presence detection sensors 90 are
located at the
lower extent of each storage unit 20', again such as by mounting to the
storage unit
carriage or the like. Quadrature sensors 92 are located vertically above the
presence
sensors 90, typically at waist or knee height. The quadrature sensors 92
function to detect
the direction of movement of a person or object into or out of the aisle
between storage
units 20'. While positioning quadrature sensors 92 above presence sensors 90
provides a
reliable indication as to entry or exit of a person or object into or out of
an aisle, the
elevated quadrature sensors 92 must be mounted to the storage unit 20'
separately from
presence sensors 90 in separate housings, and additional wiring must be routed
to the
elevated quadrature sensors 92. Positioning the quadrature sensors 42 at the
lower extent
of the aisle 30 as in the present invention, in combination with the closely
spaced exit zone
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sensors 40, enables the quadrature sensors 42 to be mounted to the carriage 22
along with
the presence sensors 38 and the more exit zone sensors 40. This eliminates the
need for
the separate housing and mounting of the quadrature sensors, as well as
routing of wiring
to the separate quadrature sensors.
While the invention has been shown and described with respect to a particular
embodiment, it is contemplated that various alternatives and modifications are
contemplated as being within the scope of the present invention. For example,
and
without limitation, the sensors incorporated in the sensing system of the
present invention
are shown and described as having both an emitter and a receiver. As shown,
this requires
facing sensors on each side of the aisle. It is also contemplated that one or
more of the
sensors on one side of the aisle may be replaced with one or more reflectors.
In this
version, a beam emitted from a sensor on one side of the aisle is transmitted
to the
opposite side of the aisle, and is then reflected back and received on the
same side of the
aisle from which the beam is emitted. This configuration further reduces
installation time
and complexity of the sensor system. Various alternatives and embodiments are
contemplated as being within the scope of the following claims particularly
pointing out
and distinctly claiming the subject matter regarded as the invention.
