Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
BACKGROU~D OF TE~E INVENTION
: ~he present~invention~rel tes to an apparatus ::
~or sensing the presence of objec~s within a sel ted
reglon~o~ space. In~ particular ~he present i~vention~
relates~to ob~ect s:ensin~device ~which are us~ful i~
~5 ~ co~nectLo~ with ;the~operation~of automatic~doors or:o~her
automatIcally moving~equipment.:~
In ac~cordance~with~ e pri~or art, lt has been~
k~o~n to make use~of light~or~radiation emitting~equipment
: and radiation detecting eauipment: for the~purpose o~ sensin
10: t~he presence~of an~object ~or person~in a partic~lar r~io~
~: of space.~ One~applicatlon~far s:uch~object sensing equipment
:; :is in~cannecti:on:wi:th~;~ e operation of an aut~matically
opera~ed door. In thi5 case it is desirable to ~rrange
the equLpment to~sense ~he approach of a person or an object,
15~.: such as~a:shoppLng cart, ~rom one direc~io~ O! the door in
:order ~o activate the door to move it to the open position.
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It is likewise desirable to sen~e the pr~s ~ce of an
object or person on the opposite side of t.he door tO
prevent the door from striking the person during the opening
operation. Another sensing function is to determine when
5 the person has passed through the doorway, and clear of
'rhe swing of the door, to ena~le closing of the door af'cer
the person has ~ntered through the doorway.
The most reliable method fGr sensing the p~esence
of a person know~ in the art is to provide pressu:re sensitive
10 doormats which provide a signal in response to ~he weight
of a person standing thereon. Such doormats must be pro-
vided on both sides of the door. On the approach side the
doormat senses the presence of a person who wishes to pass
~hrough the doorway. On the inside of ~h~ door, in ~he
area which includes the swi~g path o f the door, the mat -is
provided to sense the presence of a person or object in
the pa~h of ~he door and provides a signal which preYen~s
. the d~or ~rom opening and causing injury to the person or
damage to: the object thereon. The inside wing pat~h doorm2t
is also used to prevent closing of the door during the time
when a person is passing through the doorway. After there
is no weight on either of the doormats the door is permitted
to close.
The use of pressure sensi~ive doormats i~ connectio~
25 Wlth t~he operation of a swinging door in accordance with the
prior art, while being the most reliable method for detecting
~he presence o~ a person or object, h~5 a disadvantage, which
is nor~ally associated with the use of a doormat i~stallation
:`
on a high tra~fic floor. The doormats used to sense the
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presence of ~ person or object are subject to wear ~rom
the passage of traffic ~hereov~r. In addition, ~he doormats
are usually in an o~tdoor entry loca~ion where they will be
subje~ted to rainwater and to damage from ice, snow, and
possibly salt o~ othex corrosive chemicals used to clear ice
and sn~w.
A further problem with the door~t sensing devices
is the fact that it beomces difficult to ~ell when the
device has failed. Failure of the swing path doormat can
result i~ injury to a person and consequent liability to
the owner or occupant of the premises i~ which the door has
been installed.
There have also been provided object sensing
.
devices wXerein a radiation source is provid d which sends
radiation along a selected path at a radiation sensing
15 element. When an ob~ect or person enters the path: of -the
radiation, the absence of the radiation being~received at the
sensing element provides an indication that there is an
object or person in the path of the beam. The use of this
beam-path type sensor provides a certain n fail safe" re-
liability because ~f the fact that a beam must pass com-
pletely ~hrough the path in order to be detected and provide
an indication OL a safe condition. It becomes neces~ary,
however, in connection with the operation of a swinging door,
~ to pro~ide a great many e~l tters and detectors to provide
adequate assura~ce that a small child is not within the path
of the swinqing door.
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U . S . Patent 3, 852, 592 ~o Scoville describes
a prior art door opening control apparatus which includes
n e~itter mounted above the doorway which sends infrared
xadiation along ~ downwardly directed energy beam which spans
a path of travel of pedestrian traffi~ approaching the doorway.
- There is provided a sensing element which i5 mounted on ~he
jam of the doorway and which has a receiving beam pa~tPrn
of sensitivity which is generally horizontally disposed,
so that ~here is p~ovided an intersection of the infrared
radiation beam ~rom the ~mitter and the horizontal sensing
beam pattern fxom the re~ceiver, which defines a protected
area in space. The patent states that addi~ional emitters
may be provided, as required, to provide additional protect;on
in additional regions in space.
While the appara~us described by Scoville
~ay be effective in ordinary ~ircumstan~es for detecting
objects which are in the re~ion defined by the intersectio~
of the two beams, problems may arise from the fact that
the door swings into the region of lntersecti~n o~; the two
2Q be~ms, and may provide some interfexence with operation of
.; the system. In addition, the system may be sensitive to
its installation, since the emitter and the detector are
located at different locatlons, a~d the operation of these
devices is sensiti~e to their locations and to thelr en~iror.-
~ men~. Further, the system may fail to detect small objects~
. ~or example an in~a~t crawling below the horizontal beam.
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~ t is therefore an ob~ect of the presentinventon ~o provide a new and improved object detectiny
apparatUs.
~ t is a further object of the precent invention
to provide such an apparatus which h2s a single location
S ~or emutters and detectors~
I~ is a further object of the prese~t invention
to pro~ide su~h an apparatus which is less sensi~ive to the
~nvironmen~ of its i~stallation, and is less sensitive
to changes i~ the reflectivity of ~hs object to b~ detected.
5~
In accordance with the invention ~here is
provided a control apparatus for an autom~tic door which
has a motor operated means for swinging the door open in
a selected ~irst direction path from a door frame in response
: 15 to the approach of an object fro~ a second direction, and
; f o~ i~hihi ting o peration o f ~he motor operati~g means in
response to the presence of an object in the ~i~rst direction
path of ~he door~ The control apparatus includes first
and se~ond object sensing appara~us mounted on:~the door a~d
facing respectively in the_first and seco~d directions from
the doox. The first and sec~nd sensing apparatus each consists
of a plurality o transmitting elements for emitting a di-
verging beam of radiation in response to supplied electrioal
signa}s,~ and means for simultaneously supplying electrical
signals to all of the elements in each sensing apparatus t
Each sensing apparatus also includes a plurality of radiation
detecting elements for receiving radiation reflected from
; an obj~t, and a receiver connected ko the de~ecting elements
~or provlding an output signal representative af the presence
o~ an object. The apparatus also includes a control circui~
for (1~ acti~ating the motor means to vpen the door in
response ~o an output signal from the sec~nd sensing appa-atus,
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~ 2 ) activating S~he mc>tor mear~s to main ain t~e d~or in an
open posi~ion ln response to an outpu~ signal from the
second sensing apparatus and (3) inhibiking operation of
the motor means and preventing opening of ~che door in response
to an output signal from the first sensing ~ppara~us.
The control apparatus can be arranged so that
the control circuit is no~c operative to inhibi opening
of the doi~r af ter t~e motor means is opexated and the door
is opened by a selected amount. This preven.ts the presence
of a railing or a wall adjacen~ door opening from
preventing further opening of the door. There may also
be provided a radiation e~itting means arranged to direct
radiation along a path to the detecting elements of ~he
first sensing apparatus when the door is opened. The
control means is then arranged t o activa~e the emitting
means after the door is opened by a selected amount, and
`~ the control means is arr~anged tD inhiblt operation of the
motor means upon obstruction of~the path between ~he emitting
means and ;the detecting e1ements of the first sensing apparatus.
The sensing apparatus of the invention may also
be used in connection with machine tools, automatic transport
~ehicles, elevator doors and similar equipment for preven ing
such equipment from s~triking~an object or person.
: ~or a better unders~anding of the present invention,
together with other and further objects, reference is made
.
to:~the fvll~wing description, taken i~ conjunction with the
occompanyin~g drawinss, and its scope will be pointed out
i n th~3 appendea claims.
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BRIE~ DES CRIPTION 9F THE DRAWINGS
~ ig. 1 illustrates the sensing apparatus of ~che
present irlvention in schematic form.
~ ig. 2 illustrates the sensing apparatus of the
5 present irlvention as installed on an au~omatic opera,ing door.
Pig. 3 is a ~op view 4f the door o~ ~ig. 2.
Fig. 4 is a side view of the door of Fig. 2
illus~rating t~e rad~ a~cion and rec:eiving patterr. of the sensor
assembly .
~ig. 5 is a top view of the ~ig. 2 door illustrating
the sensor assembly transmitting and receiving pattern.
Fig. 6 is a cross-sect~ on view of a sensor as~embly
suitable for use in connection with the door of Fig. 2.
Fig. 7 is a front ~iew of the sensor assembly of
Fig. 6.
Fig. 8 is a schematic diagram of the Fig. 6 sensor
assemblv.
Fig. 9 1S a b1Ock diagram illustrating the arrange
ment o~ ~ the control apparatus usable for oper ing the door
of Fig. 2.
DE~ P~ )N ~ I~ ON
In ~ig. 1 the~ is shown a schemati~ diagram of the
sensox~ ass~bly in accordance Wit'.l the present i~vention.
In ~he~Flg. 1, diagram the sensor asseIrbly 10 includes a
source 12 for generating electrical signal~, preferably p-~lse
signals having a pred~termined frequency such as a few kilohextz.
The output of sign 1 souIce 12 is provided to light-emitting
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diodes, which are ~onnec~ed in series wi~h signal source 12.
Those skilled ir~ the art will recognize that it will also
be possible to connect the light-emitting diodes lJ, in
parallel with the output of sigr~al source 12, according to
5 the voltage output of ~he sig~al source and the impedance
of the diodes. Each of the light-e~nitting diodes 14 is
arranged to radiate a di~7erging patterrl of radiation. In
the embodiment illustrated in Fig. 1 the light-emit~ing
diodes 14 are each arranged to radiate in a conic21 pattern
with an interior angle 18 which is approximately equal to 90.
Accordingly, objects 22, 24 and 26, which are wi~hi~ ~he
radiation pattern of one or ~ore of the light-enitting
diodes 14 will receive radiation such as opticaI or infra-
red radiation, which is emitted from the diodes.
lS The sensor assem~ly~ of Fig. 1 also ~includes a
plurality of radiation detectillg elements 16, such 2s photo-
transistors. The photo-transistors 16 are arranged to have
a diverging beam of radiation sensitivity, appro ~ mately
the same shape as the beam o. ~the :Ligh:t-emittins diodes 14.
20 Accordingly, lisht or infrared radiation, eraitted by light~
emitting diodes 14, and re'lected fro= an objest 22, 24 or 26
within the region o~ space illuminated by the sensor asse~nbly,
will be reflected back into the light detecting elements 16
~and~ geDera~e therein an electrical signal. It shc~uld be
25 noted that because of the diverging beams of radlation of
the light-emitting diodes 14 and the diverging beam of
sensitivity of the light-sensing elements 16, it will be
possible for radiation, emitted by ar~y of the diodes ~ to be
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~7~t~)
re~lected off an object in the object field and received
by a plurality of the light-sensitive elements 16. This
~eature tends to increase the sensitivity of the sensing
apparatus for rela~ively cl~se objects, and thereby enables
the easy detection ~f objects in the adjoining region of space,
even i~ those objects have varying amounts of radiatio~ re-
~lectivity at the frequency of emission of ~he light sources 14.
The light sensing elements 16 are connected in
parallel and their outpu~ signals are provided as an input
to receiver 20. ~eceiver 20 preferably includes a tuned
amplifier which is responsive to frequencies in the range
of the output f.requency of electrical si~nals from signal
sourc~
: The detect~ng apparatus of Fig. 1 is particularly
useful in conn~ction with automatically operated mechanical
: equipment~for sensing the presence of an obstacle. In this
: respect, the sensing apparatu~ of Fig. 1 is preferred to the
`~ ~ conventio~al reflection type object sensing apparatus by
: reason o~ the fact that it has a drastically reduced ran~e
of sensitivity to an object, and is less susceptible to
variations in object detecting range with varia~lon in
radiation reflectivity of the object. Prior art reflect;on
:
type object sensing apparatus'~kes use of a focused beam
of light, which~:is directed o-ltward in the dirPction from
2S which an objec~ is anticipated to approach. The radiation
is reflected ~ff the object and recei~ed by a sensing apparatus
which also:has a relatively narrow focused beam which is
oriented in the identical direction. The range at which
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an object will be sensed by this 'cype of apparatus will
depend largely on the reflectivity o~ the object. An object
such ~s a re~:ro-reflecting device, which sends back a re-
latively ~ocuse d be am o f radi a ~ci on t~w a rd the emi tter wi ll
5 cause a very large response in the receiving device and may
be detected at a very large range. ~ object which has
relatively low reflectivity, such.as a dull black overcoat,
will not be detected until it is very close to the radiation
detec~or.
3ecause the sensing apparatus illustrated in
Fig. 1 uses diverging rather than focused beams of radiation
for both the radiation emitting devices and the radiation
detecting devices, it is susceptible to receiving and res?ondins
to radiation reflected off objects only within a limited
range where multiple emitters illuminate the object and
multiple receivers detect the reflected sig~al. Therefore,
the radiation detector iS not likely to respond to an object
at a relatively far distance, éven i~ tha~ object is highly
reflective, since both the illuminatior. of the object and
the sensltivity of the detectors is greatly reduced with
distance as compared to focused beam illumi~ation and detecting
devices. In contrast, :the sensing apparatus will respond
relatively strongly to an object which is relatively close,
beca~e even thou~h the re~lection from ~h~ object may be
di fused ~nd scattered ! it will be received by multiple
~etecting elements in the receiving array, and therefore,
: the outputs of these elements as currents will add in ~he
receivex, and provide an adequate response to provi de an
~utput indication of the presence of the object.
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Fig. 2 is a perspective view and Fig. 3 is ~ top
cross-sectional view of an automa~ically operated door 30
having a sensing apparatus 10 in accordance with the presen'c
invention. The door 30 is mounted within wall 28 and is
S opened and closed by means of a motor apparatus 33. On
each side of the door there are provided guard rails 34,
36, 38 arld 40 , which are arranged to prevent appr~ach t~ward
the door from directions other than straight-on. The door
o~ Fig. 2 is arranged to open in a first direction which is
away frc)ra the side lllustrated in Fig. 2, ~nd alons the pa~
31 to the position 30' which is illustrated in Fig. 3. Op~qing
of the door 30 by motor 33 is effected in response to the
detection of an object by sensing apparatus 10, w~ich is
mourlted 021 the side of the door illustrated in Fig, 2
facing ln a second direction with respect to: the door.
T~e door is provided with a second object sensing apparatl~s
15 which is mounted on the sIde of the door facing in the
~i~st direction corresponding to the door opening path.
Sensi~g apparstus 15 is utilized by the door con,~ol a~pa_a,us
to prevent opening of the door when there is an obstruction
in the path of the door, such as a person standing ~ex* to
the door. The sensing apparat~s 15 inhibits the opera~ion
of the door when an object or person:is sensed in its path
i n order to pre~ent damage to ~e door or inj~ to the person.
Z5 ~ The object sensing devices 10 and 15 which are
mounted on the door 30 are illustrate~ sc:~ematically in
~ig. 1. Fi~s. 4 and 5 illustrate respectivPly the elevation
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~ 1 ~ 7 ~
and azimuth radiation transm~tting and receiving beams
for the sensing devices 10 and 15 The appar~tus 10 has
a radiati~g surface which is anslea at approximately 30
~rom the vertical in order to orient the elevation radiation
S beam in a slightly upward ~rom horizontal direction. The
radiation beam has an approximately 90 half power beam
width so that it radiates in~o an area 42 illustrated in
elevation in Fig. 4 and in zzimuth in Fig. 5. The device
10 is mounted approximately 15" above ~he floor on door 30
to detect objects near the bottom of the door.
The radiation sens:ing apparatus 10 is illustrated
in grea~er detail in Figs. 6 and 7. The apparatus includes
a pair of U-shaped channels 46, 4R, made of opaque material,
such as extruded aluminum. The channels have an outer surface
whlch is CUt o~f at the 30 angle illustrated in Fig. 4,
and they~are covered by ~ light transmutting cover 5~,
preferably have a:tinting suitable t~:transmit and re~eive
primarily radiation in the freq~ency band of oper tion of
the light-emltting diodes 14. The light-emit.ing diodes 14
are containe~ in the upper channel 46. The photo-sensitive
transistors 16 sre~ cont5ined ln a lower-channel 48. The
1QCatiOn Of the light-emitting d odes -and photo-sensitive
;
transistors ln ea d o~ the channels l5 such ~s to provide tne
O radistion beam width which is illustrated in Fig. 4 and
shown as dotted lines in Fig. 6. ~t the bottom of each o ~he
chsnnels 46 and 48 of the extruded membex 44, there are
prov~ded circuits 52 for connecting the light emitting diodes
and the photo transistors to the signal generating and
receiving apparatus.
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In the front plan view of ~ig. 7, ~he spacing of
the elements of the sensor assembly 10 is illustrated in
greater detail. In ~he preferred e~mbodiment illustrated,
the light-emittir.g diodes 14 are arran~ed with approximately
: equal spacing along a first path which consists of a horizontal
straight line down the center of ~le upper ~hannel 46. The
photo t~ansistors 16 are arranged with sLmilar equ~l spacing,
interspersed with the diodes 14, along ano~her straight path,
: wh ch c~nsists 9- the center line of the lower channel 48.
The spacing between adjacent photo transistors ~nd light-
10 emitting diodes, design2ted spacing A in Fig. 7, is pre
~erably selected to be approxi~ately 20 mullimeters or less.
; ~ The spacing B between .he paths on which are located the
light-emltting diodes 14 and the photo transistors 16 is
preferably no more than 16 millimeters. S~acings A and B
which are greater than ~he recommended am3unts ha~e been
found ~o maXe it dif~icult to o~tain a response from
, small objects, such as ~ticks the size o~ fingers, within
:: the region of spaçe 42 illustrated in Figs. 4 and 5.
With the suggested spacing the device 10 will sense small
objects out to a distance of approximately ~ to 8 feet.
Natu~ally the range of the sensing apparatus can be adjusted
according to ~e intensity of the diodes 14 and the sensitivitv
: of the detect~rs 16 a~d the receiver.
Fig. 8 is a circuit diagram illustrating the
~ixcuits for the sensing apparatus 10. As illustrated in
Fig. 8 the light-emitting diodes are co~nected in series
to a signal source 12, and optically coupled to the photo
transistors by means of re1ection off an object~ Photo
translstors 16 are ~onnected in par~llel to drive a t~ned
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amplifier 54 in the receiver 22., The output of the t~ned
am~lifier is detected by a rectifier 56 and pro~ided to a
DC amplifier 58 which can operate a relay or other deci~io~
logic used in connection with the operation of the door.
~ig. 9 illustra~es a block diagram of the control apparatus
usable in connection with the door 30 of Fig. 2 The
contxol unit, which may be a programmed microprocessor
or equivalent logic circuits, is connected to sensing
apparatus 10, sensing apparatus lS and also in a preferred
embodiment khere may be provided an additional light source
32 which is arranged on barrier 40 as illustxated in Fig. 3.
The output of the control unit is connected to motor 33 and
is ~rranged to operate the motox to open and close the door
30.
The control circuit illustrated in Fig. 9 under
normal conditions operates to open the door in response to
an object detec~ing signal emitted by detecting apparatus 10.
Detect;ng apparatus 15 operates to inhibit activation of
door openins when an ob j ect obs tructs the door . Accordinsly
control unit 54 will not open the door when a signal is
received from ~nit lS, even if a signal is received from
unit 10.
It will be recognized tha. as door 30 opens
contr~l unit 15 will respond to the presenee of barrier 40
in the path of~the door and provide an output indication
to control unit 54 indicating that an object is in the
path~of the door. This, under oxdinary circumstances,
would s~op khe further opening of the door. In order to
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prevent this false detection, ~he sensi~g u~it 15 is
inhibited by a signal ~rom position switch 56 which indica~es
that the door has ope~ed to a certain selected angle, for
example, position 39. Signals received from detecting
apparatus 15 indicating the presence of an object in the
path of the door are no longer operati~e to prevent ~he
control un' t from effecting the con~inued opening of the
door a~ter switch 56 is activa~ed. Such inactiva,ion of
~he operation o~ sensing apparatus l; may cause a hazardous
condition because of the fact that, after the control unit
is inhibited, a child can enter the path of the door and
be injured by the door. In order to provide further safety
under this circumstance, barxier 40 may be provided with
light-emitting means 32 which emits light in the direction
of Senslng apparatus 15 af ter the position switch 56 is
activated by opening of the door to positio~ 39. Thexeafter
light passes directly from unit 32 to detecting apparatus 15,
and causes an output signal from apparatus 15. At this poi~t
.
. the output signal from apparatus 15 is considered to be a
positive signal, and the further opening of the door will
: be inhibited only upon the interruption of the Iight path
between unit~32 and detecting apparatus 15.
In many automatic door installations based on the
present inventionj it will be desirable to provide a
.
suitable fixed sensing system for detecting objects which
: ~ approach the door when it is partly to fully open, Because
: : the diveryent beam 42 from the 5ensin~ apparatus lO mounted
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on the approach side of the door 30 (see Fig. 5) move~
with the door, it is lncreasingly less apt to detect
objects approaching the door, the wider open the door is.
Th~refore, if an object follows behind another object
at a distance 5uch that the first object leaves ~he detection
field as the second object approaches, there will be a
period when the beam 42 cannot detect the approach of
the second object toward the door opening, and the door
may begin to close as the second object approaches or
begins to pass through. Hence, a fixed position detection
device, such as anotner sensing apparatus in accordance
with the present invention or a microwave apparatus,
located~above the door or to eitner side of the approach
pat~, should be provided to detect objects approaching
when t:e door is partly to fully open. The fixed-position
detector can be normally de-energized and energized
in accordance with~door position only when the door is
partly to fully open and can override the sensing apparatus 15
and keep tne motor apparatus~33 2nergized whenever it
; 20 detects an object approaching the door.
~While the preferred embodiment O~ ~h^e invention
hzs been de~scribed ln connection with 2 motor o~erated
swinglng~door, tnose skllled in the art will recogni~e
tnat thls and other em~odiments Wil7 be useful in
connection with sliding doors, elevator doors, sel.
operated vehicle5 or other automatically movins devices.
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While I have described what I believe to be
the preferred embodiments o~ the invention, those ~killed
in the art will recogr.ize that o~her and further changes
and modifications may be made thereto, and it is intended
to claim all such chaDges as fall within ~he true scope
of the invention.
The term "light radiation" as used in the
accompanying claims is to be understood as including the
infra-red, visible and ultravlolet regions of the spectrum.
This is a division of Canadian Patent Application
Serial No. 353,057, filed May 30, 1980.
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