U.S. patent number 3,914,601 [Application Number 05/456,256] was granted by the patent office on 1975-10-21 for compact viewing assembly for light sensitive sorting machine.
This patent grant is currently assigned to Petty-Ray Geophysical, Inc.. Invention is credited to Michael C. Hoover, William C. Long.
United States Patent |
3,914,601 |
Hoover , et al. |
October 21, 1975 |
Compact viewing assembly for light sensitive sorting machine
Abstract
In a light-sensitive sorting machine for sorting a succession of
freely falling articles, a compact viewing assembly includes a
passage through which the articles may fall, a housing surrounding
the passage to define an enclosed viewing chamber, background
members carried in the housing at spaced locations around the
passage, optical viewing means disposed to view the background
members and articles falling through the passage between the
viewing means and the background members, and a plurality of lamps
spaced in a plane around the passage to uniformly illuminate the
background members and articles falling through the passage, each
of the lamps being shielded to prevent direct illumination of the
optical viewing means.
Inventors: |
Hoover; Michael C. (Houston,
TX), Long; William C. (Houston, TX) |
Assignee: |
Petty-Ray Geophysical, Inc.
(Houston, TX)
|
Family
ID: |
23812073 |
Appl.
No.: |
05/456,256 |
Filed: |
March 29, 1974 |
Current U.S.
Class: |
250/226; 209/908;
209/587 |
Current CPC
Class: |
B07C
5/3425 (20130101); Y10S 209/908 (20130101) |
Current International
Class: |
B07C
5/342 (20060101); H01J 005/16 () |
Field of
Search: |
;250/226,223
;209/111.6,111.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawrence; James W.
Assistant Examiner: Nelms; D. C.
Attorney, Agent or Firm: Arnold, White & Durkee
Claims
What is claimed is:
1. In a light-sensitive sorting machine for sorting a succession of
articles freely falling along a predetermined path, a compact
viewing assembly comprising:
a transparent tube through which articles to be sorted may fall
along said path;
a housing surrounding a portion of said tube to define an enclosed
viewing chamber;
a plurality of background members disposed at spaced locations in
said housing, each of said background members being equidistant
from said path;
a plurality of optical viewing means disposed in a plane normal to
said path to view articles falling along said path against
respective of said background members;
a plurality of lamp means disposed in said plane to illuminate said
articles and said background members, each of said lamp means being
equidistant from said path; and
shield means disposed proximate each of said lamp means to prevent
direct illumination of said optical viewing means by said lamp
means.
2. In a light-sensitive sorting machine for sorting a succession of
articles freely falling along a predetermined path, a compact
viewing assembly as recited in claim 1 wherein each of said lamp
means includes a lamp filament and said shield means comprises a
ribbon-like element disposed to prevent the projection of images of
the lamp filaments on the viewed area of the articles and the
viewed area of the background members by the respective lamp
means.
3. In a light-sensitive sorting machine for sorting a succession of
articles freely falling along a predetermined path, a compact
viewing assembly as recited in claim 2 wherein said ribbon-like
shield elements are disposed in the plane of said lamp means.
4. In a light-sensitive sorting machine for sorting a succession of
articles freely falling along a predetermined path, a compact
viewing assembly as recited in claim 3 wherein one of said lamp
means is disposed adjacent each of said background members to
uniformly illuminate said background members.
5. In a light-sensitive sorting machine for sorting a succession of
freely falling articles, a compact viewing assembly comprising:
a cylindrical housing having an upper plate, a lower plate spaced
from said upper plate, and a cylindrical side wall joining said
plates, each of said plates having respective concentric openings
therethrough defining a central passage through which articles to
be sorted may fall;
a plurality of background members disposed within said housing at
spaced locations about said central passage proximate said side
wall;
a plurality of optical viewing means disposed within said housing
at spaced locations about said central passage, each of said
viewing means being disposed to view one of said background members
and articles passing through said housing between said background
members and said viewing means;
a plurality of lamp means disposed about said central passage in
said housing to illuminate said background members and said
articles falling through said passage;
said viewing means and said lamp means defining a plane normal to
said passage; and
shield means disposed proximate each of said lamp means to prevent
direct illumination of said optical viewing means by said lamp
means.
6. In a light-sensitive sorting machine for sorting a succession of
freely falling articles, a compact viewing assembly as recited in
claim 5 wherein said background members are supported by at least
one of said plates and said optical viewing means and said lamp
means are supported by said side wall.
7. In a light-sensitive sorting machine for sorting a succession of
freely falling articles, a compact viewing assembly as recited in
claim 5 wherein said central passage is defined by a length of
cylindrical transparent tube passing through said housing.
8. In a light-sensitive sorting machine for sorting a succession of
freely falling articles, a compact viewing assembly as recited in
claim 5 wherein one of said lamp means is disposed adjacent to each
of said background members to uniformly illuminate said background
members.
9. In a light-sensitive sorting machine for sorting a succession of
freely falling articles, a compact viewing assembly as recited in
claim 5 wherein each of said optical viewing means includes a lens
disposed to receive light energy reflected from respective of said
background members and from said articles to be sorted and to form
a corresponding light beam, a beam splitter disposed to divide said
light beam into first and second optical paths, first and second
color filters disposed in respective of said paths, first and
second optical frame members disposed proximate said respective
filters, and first and second photosensitive elements disposed to
receive light energy passing through respective color filters and
optical frames and to produce electrical signals representative of
the respective energy levels of said paths.
10. In a light-sensitive sorting machine for sorting a succession
of freely falling articles, a compact viewing assembly as recited
in claim 9 wherein at least one of said optical frame members is
adjustable with respect to the corresponding light path to vary the
image incident on the corresponding photosensitive element.
11. In a light-sensitive sorting machine for sorting a succession
of articles freely falling along a path, a compact viewing assembly
comprising:
a housing surrounding said path to define an enclosed viewing
chamber through which articles to be sorted may freely fall;
background means disposed within said viewing chamber at spaced
locations around said path;
a plurality of lamp means disposed within said viewing chamber in a
plane normal to said path for illuminating said background means
and the articles falling through said viewing chamber;
shield means disposed proximate each of said lamp means for
preventing the projection of a lamp filament image onto said
background means and onto the articles falling through said viewing
chamber; and
a plurality of optical viewing means disposed within said viewing
chamber in said plane for viewing the articles falling through said
viewing chamber against said background means.
12. In a light-sensitive sorting machine for sorting a succession
of articles freely falling along a path, a compact viewing assembly
comprising:
a housing surrounding said path to define an enclosed viewing
chamber through which articles to be sorted may freely fall;
background means disposed within said viewing chamber at spaced
locations around said path;
a plurality of lamp means disposed within said viewing chamber in a
plane normal to said path for illuminating said background means
and the articles falling through said viewing chamber;
shield means disposed proximate each of said lamp means for
preventing the projection of a lamp filament image onto said
background means and onto the articles falling through said viewing
chamber; and
a plurality of optical viewing means disposed within said viewing
chamber in said plane for viewing the articles falling through said
viewing chamber against said background means, each of said optical
viewing means including a lens disposed to receive light energy
reflected from said background means and the articles falling
through said viewing chamber and to form a corresponding light
beam, a beam splitter disposed to divide said light beam into first
and second optical paths, first and second color filters disposed
in respective of said optical paths, first and second optical frame
members disposed proximate respective of said filters, and first
and second photosensitive elements disposed to receive the light
energy of the corresponding optical paths to produce electrical
signals representative of the respective light energies, at least
one of said optical frame members being adjustable with respect to
the corresponding light path to vary the image incident on the
corresponding photosensitive element.
Description
BACKGROUND OF THE INVENTION
This invention relates to sorting machines, and, more particularly,
to light-sensitive sorting machines for sorting a succession of
freely falling articles from one another responsive to color
differences in the light energy reflected from the articles.
Previously, viewing assemblies for light-sensitive sorting machines
have required sources of illumination located both above and below
the viewing means in order to sufficiently illuminate the articles
being sorted for high capacity color sorting. The complexity and
bulk of such viewing assemblies has been such as to require an
undue amount of space and unnecessary complexity of such sorters,
particularly when it is desired to arrange a large number of such
sorters in parallel to obtain a high sorting capacity in a minimum
of floor space.
In addition, the shielding of illumination sources in prior
machines has been inefficient, presenting tortuous paths for
reflected light energy to follow before illuminating the item being
sorted or producing undesirable shadows. A compact, efficient,
viewing assembly which will provide illumination suitable for high
speed bichromatic sorting has not heretofore been available.
SUMMARY OF THE INVENTION
The present invention provides a compact viewing assembly for use
in light-sensitive color sorting machines. In particular, a highly
efficient broad wavelength spectrum assembly especially suitable
for high speed bichromatic sorting applications is provided.
In one embodiment of the present invention, a succession of
articles to be sorted is provided to a viewing assembly by way of
an elongated tapered slide adapted to receive the articles at its
upper end and to singulate the articles for presentation to the
viewing assembly. As each article leaves the bottom of the slide,
it falls freely along a predetermined path through the viewing
assembly.
In the embodiment under consideration, a clear or transparent
plastic tube surrounds this path and is in turn surrounded by a
generally flat cylindrical housing. This housing contains
background members against which the articles are viewed by optical
viewing means and also contains a plurality of tungsten filament
lamps spaced around the tube to uniformly illuminate articles
falling therethrough with the background members with a broad
spectrum of light wavelengths. The optical viewing means and the
lamps are centered in a single plane within the housing to permit a
compact assembly.
The background members are located near the outer side wall of the
cylindrical housing, and the lamps are located to one side of the
backgrounds. The lamps project into the housing and provide sources
of illumination which are closer to the path of the articles than
are the background members. Narrow, ribbon-like lamp guards are
provided around each of the lamps to prevent direct illumination of
the viewing means. These lamp guards and the lamp filaments are
aligned to prevent projection of the lamp filaments onto the
articles and backgrounds. The plane in which the lamps are centered
is normal to the path of the articles through the viewing assembly.
Also, a compact bichromatic optical viewing device is provided and
includes adjustable frame means for presenting the same viewed area
to each of two photosensitive elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a single channel sorting machine in
accordance with one embodiment of the present invention.
FIG. 2 is a top view of the viewing assembly of FIG. 1.
FIG. 3 is a side view of the optical unit as shown in FIG. 2,
partly in section and partly in schematic, illustrating one
embodiment of a compact optical viewing means in the present
invention.
FIG. 4 is a top view of an alternate embodiment of the viewing
assembly of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, the sorting machine 10 includes an
elongated tapered slide 11. The slide 11 is inclined from the
vertical to provide gravity assisted singulation of the articles to
be sorted as the articles slide downwardly thereon. Above the slide
11 are mounted a stationary hopper 12 and a vibrating chute 13 for
feeding articles to be sorted from the hopper to the upper end of
the slide.
At the bottom end of the slide 11, the articles to be sorted shoot
out with considerable velocity on a predetermined trajectory which
is substantially a straight prolongation of the slide for a short
distance. At the bottom of the slide 11, viewing assembly 20 is
supported by structural mounts 21 to receive the articles to be
sorted as they leave the bottom of the slide 11. Ejector 22 is
mounted immediately beneath viewing assembly 20 for deflecting
undesired articles as they exit the viewing assembly. The desired
articles continue their predetermined path and exit the machine
through an exit tube 24, while the unacceptable articles are
deflected into collector 26 from which they may be removed through
discharge opening 28.
Referring now to FIG. 2, one embodiment of the viewing assembly of
the present invention is illustrated in detail. The viewing
assembly includes a transparent tube 30 through which articles 32
may fall for inspection. A housing 18 surrounds a portion of the
tube 30 and includes an upper plate 58, a lower plate 59, and an
outer wall 34 joining the peripheries of the plates to describe a
generally flat cylinder having a central passage therethrough.
Outer wall 34 of the viewing assembly 20 supports optical viewing
means such as viewing assemblies 36, lamp bases 38, and lamp guards
40, by means of mounting screws 42. The structural mounts 21 by
which the viewing assembly 20 is attached to the sorting machine
10, are attached to side wall 34 of the viewing assembly by screws
44. Background members 50 are supported by the upper surface of the
viewing assembly by conventional means such as screws 52 and blocks
54 (FIG. 4). Lamps 48 are mounted in lamp bases 38 in conventional
fashion.
Lamps 48 are arranged to define a plane. The filaments 47 of the
lamps 48 are preferably oriented in this plane to facilitate most
efficient shielding of the lamps, as will be discussed. In
addition, by centering the optical viewing means 36 and the
backgrounds 50 in this same plane, an extremely compact and highly
efficient viewing assembly is achieved. Narrow ribbon-like lamp
guards 40 are provided around each of the lamps 48 to prevent
direct illumination of the viewing means 36 by the lamps. In
addition, the lamp guards 40 prevent the projection of shadows
corresponding to the lamp filaments 47 on the article to be sorted
32 and the backgrounds 50. However, by utilizing the ribbon-like
lamp guards 40, the upper and lower regions of the interior of the
housing are directly illuminated. The interior surfaces of the
viewing assembly, as well as the lamp guards 40, are painted with a
flat white paint to minimize specular reflection and provide a
substantially uniform level of diffused light throughout the area
viewed by the optical viewing means 36.
By locating the background members 50 proximate the side wall 34 of
the viewing assembly, and locating the lamps 48 more closely to the
center of the viewing assembly, and adjacent the background
members, the background members are thereby provided with uniform
illumination of the adjacent lamp, and the light energy reflected
from each of the background members is substantially unaffected by
the passage of articles to be sorted through the viewing assembly.
The paths of light energy reflected from articles 32 and
backgrounds 50 and sensed by the optical viewing means 36 are shown
schematically in FIG. 2.
It will be appreciated that the leading and trailing edges of the
articles to be sorted 32 passing through the viewing assembly
represent the most difficult areas of such articles to inspect for
sorting purposes. By use of the narrow ribbon-like lamp guards 40
oriented with the lamp filaments 47 in the plane defined by the
optical viewing means 36, the leading and trailing edges of
articles 32 are well illuminated by apparatus in accordance with
the present invention.
Optical viewing means 36 include conventional lens and frame means
for focussing the light energy reflected from the corresponding
background 50 and the articles to be sorted 32 on an appropriate
photosensitive element or elements through respective color
filters.
One embodiment of a compact optical viewing means adapted for use
in the present invention is illustrated more fully in FIG. 3.
Reflected light energy is collected by lens 70 and focussed on
respective solar cells 82,84 through beam splitter 72, color
filters 74,76 and frames 78,80. The frames 78 and 80 each contain a
narrow slit 90 effectively limiting the area of view in a direction
normal to the path of travel of the articles to be sorted. While
frame 78 is fixed with respect to the light beam incident on solar
cell 82, frame 80 is adjustable by means of adjustment screw 88 and
spring 89 so that the slit 90 in frame 80 may be located to pass
the same image to solar cell 84 as that passed to solar cell 82 by
frame 78.
While the foregoing discussion of optical viewing means 36 has been
directed to a single embodiment utilizing solar cells, it will be
appreciated that other photosensitive elements may be utilized. In
addition, other lens arrangements may be used to locate an optical
frame ahead of the beam splitter, or the optical viewing means may
incorporate only a single photosensitive element for monochromatic
color sorting. The selection of various optical color filters for
use in monochromatic or bichromatic color sorting is understood by
those familiar with the art to be dependent on the colors of the
articles being sorted and the wavelength spectrum of the
illumination means available. Various means for defining
discriminating signals are described in U.S. Pat. No. 3,012,666 and
others.
When there is no object 32 within the field of view of the optical
viewing means 36, the viewing means 36 senses the light energy
reflected from the backgrounds 50. As an article to be sorted 32
falls through the transparent tube 30, the article reflects certain
wavelengths of the illumination produced by lamps 48 depending upon
the color of the article. This reflected light energy is sensed by
optical viewing means 36, and, if the article is not acceptable, a
signal is generated to fire the ejector 22 when the article 32
reaches the ejection point below the viewing assembly 20. If no
ejection signal is generated, the article 32 continues along its
predetermined path to the acceptable article discharge tube 24.
In an alternative embodiment of the present invention illustrated
in FIG. 4, air nozzles 60 are mounted in the upper surface 58 of
the viewing assembly by brackets 62 and screws 64. The nozzles 60
are connected to a source of compressed air (not shown), and may be
periodically actuated in conventional fashion to provide air blasts
inside the transparent tube to remove dust or debris which may have
settled therein.
Although the viewing assembly of the present invention has been
described in an embodiment having three lamps, three backgrounds,
and three optical viewing means, it will be appreciated that this
number may be varied depending on the size of the assembly and the
sorting machine sensitivity dictated by the colors of the products
being sorted. For example, a two-view assembly may be provided by
removing one of the backgrounds and one of the optical viewing
means, retaining the three lamps. Further modifications and
variations within the scope of the present invention will be
appreciated by those of skill in the art and may be made without
departing from the spirit thereof.
* * * * *