U.S. patent application number 09/866088 was filed with the patent office on 2002-11-28 for thermal plastic expanded foam meat tray and method and apparatus for precisely trimming the meat tray from an expanded foam web.
Invention is credited to Irwin, Jere F.
Application Number | 20020175170 09/866088 |
Document ID | / |
Family ID | 25346887 |
Filed Date | 2002-11-28 |
United States Patent
Application |
20020175170 |
Kind Code |
A1 |
Irwin, Jere F |
November 28, 2002 |
Thermal plastic expanded foam meat tray and method and apparatus
for precisely trimming the meat tray from an expanded foam web
Abstract
An unique expanded foam rectangular shaped meat tray 10 is
described having a bottom wall 12 with side walls 14, 16, 18 and 24
extending upward and outward to an upper peripheral lip 30 at an
obtuse angle "A" of between 110 degrees and 140 degrees relative to
the bottom wall 12. Internal steeply inclined curved alignment
surfaces 42 are formed at the corners of the meat tray 10 adjacent
the lip 30. The internal alignment surfaces 42 are steeply inclined
at an obtuse angle "B" of between 94 degrees and 105 degrees. The
surfaces 42 are curved in an arc of more than 90 degrees. A process
and apparatus is provided for accurately trimming the lip 30 as the
meat tray is being separated from a web 8. The apparatus includes
an alignment fixture 84 mounted on the face of punch plates 74. The
alignment fixture 84 has complementary exterior curved side corner
alignment surfaces 92 with steep angles "C" of between 75 degrees
and 86 degrees. A method is also provided.
Inventors: |
Irwin, Jere F; (Yakima,
WA) |
Correspondence
Address: |
WELLS ST. JOHN ROBERTS GREGORY & MATKIN P.S.
601 W. FIRST AVENUE
SUITE 1300
SPOKANE
WA
99201-3828
US
|
Family ID: |
25346887 |
Appl. No.: |
09/866088 |
Filed: |
May 25, 2001 |
Current U.S.
Class: |
220/660 |
Current CPC
Class: |
Y10T 83/04 20150401;
B26F 1/40 20130101; B65D 1/34 20130101; Y10T 83/461 20150401; B26F
2210/06 20130101; Y10T 83/6572 20150401 |
Class at
Publication: |
220/660 |
International
Class: |
B65D 006/08; B65D
006/10 |
Claims
What is claimed is:
1. A thermal plastic expanded foam rectangular meat tray trimmed
from a thermal plastic expanded foam web, comprising: a
substantially rectangular bottom wall; side walls extending upward
and outward from the bottom wall integrally interconnected to each
other at four corners; each of the side walls having an inclined
lower section and an upper section that extends upward terminating
in a lip that extends outward around the periphery of the tray; and
the upper wall section having internal inclined corner surfaces
extending upward and outward to the lip at the four corners
specifically provided to receive an internal complementary mating
corner alignment fixture to maintain the tray accurately aligned at
the corners as the tray is being trimmed from the thermal plastic
expanded foam web.
2. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein the upper sections of the side walls
have inside reinforcing ribs formed therein in which the inclined
corner surfaces are indented into the ribs at the corners of the
side walls.
3. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein at least one of the inclined corner
surfaces extends upward and outward to the lip at a steep angle of
between 94 degrees and 105 degrees relative to the bottom wall.
4. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein at least one of the inclined corner
surfaces extends upward and outward to the lip at a steep angle of
between 94 degrees and 100 degrees relative to the bottom wall.
5. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein the lower sections of the side walls are
inclined upward and outward at an angle of between 110 degrees and
140 degrees relative to the bottom wall.
6. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein at least one of the inclined corner
surfaces is curved having an arc of greater than 90 degrees
relative to a center of curvature.
7. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein at least one of the inclined corner
surfaces is curved and wherein the curved inclined corner surface
extends upward and outward to the lip at a steep angle of between
94 degrees and 105 degrees.
8. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein the lower sections of the side walls are
inclined upward and outward relative to the bottom wall at an
inclined angle of between 110 degrees and 140 degrees and wherein
at least one of the inclined corner surfaces is curved and wherein
the curved inclined corner surface extends upward and outward to
the lip at a steep angle of between 94 degrees and 105 degrees.
9. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein the upper section of the side walls has
inside wall surfaces that are ribbed and extend upward and outward
between the lower section and the lip at an inclined angle relative
to the bottom wall of between 110 and 140 degrees.
10. The thermal plastic expanded foam rectangular meat tray as
defined in claim 1 wherein the corner surfaces are conical shaped
having a steep angle of between 94 and 105 degrees relative to the
bottom wall.
11. A process for severing uncut thermal formed rectangular meat
trays with precisely trimmed lips from a thermal plastic expanded
foam web in which each meat tray has diagonally opposing steeply
inclined interior corner surfaces, comprising: a. moving the web to
place at least one of the rectangular meat trays between a
rectangular meat tray punch and a rectangular meat tray die, in
which the rectangular punch has an alignment fixture thereon with
complementary steeply inclined exterior alignment surfaces for
engaging the steeply inclined interior corner surfaces of the meat
trays; b. moving the punch and die relative to each other a first
distance to insert the alignment fixture within the meat tray with
the alignment surfaces engaging the diametrically opposed interior
corner surfaces of the meat tray to accurately align the meat tray
longitudinally, laterally and angularly with respect to the punch
and die; and c. while maintaining the alignment surfaces in
engagement with the corner surfaces, moving the punch and die
relative to each other a second distance to sever the meat tray
from the web with a precisely formed lip about its periphery.
12. A trim apparatus for severing uncut thermal formed rectangular
meat trays with precisely trimmed lips from a thermal plastic
expanded foam web in which each meat tray has diagonally opposing
steeply inclined interior corner surfaces, comprising: a. a
rectangular meat tray die; b. a rectangular meat tray punch
opposing the rectangular meat tray die; c. an alignment fixture
mounted on the punch having complementary exterior alignment corner
surfaces thereon for engaging the steeply inclined interior corner
surfaces of the meat tray to maintain the meat tray in alignment in
the longitudinal, lateral and angular directions; d. placement
means for placing an untrimmed meat tray between the punch and die;
e. drive means operatively connected to the die and punch for (1)
moving the punch and die relative to each other a first distance to
move the alignment fixture into the meat tray with the exterior
alignment corner surfaces engaging the steeply inclined corner
surfaces of the meat tray to accurately align the meat tray in the
longitudinal, lateral and angular directions, and (2) moving a
second distance to accurately trim the meat tray from the web with
a precisely formed lip about its periphery while the fixture corner
surfaces are engaging the tray corner surfaces.
13. The trim apparatus as defined in claim 12 wherein the punch has
a face plate and wherein the alignment fixture is mounted on the
face plate for movement between an extended position to a retracted
position while the punch and die are moved relative to each
other.
14. The trim apparatus as defined in claim 12 wherein the alignment
fixture has a generally rectangular shape with corner projections
extending outwardly with the inclined fixture corner surfaces being
formed thereon for engaging the steep inclined corner surfaces of
the meat tray.
15. The trim apparatus as defined in claim 12 wherein the fixture
corner surfaces are curved and extend downward and inward at an
angle of between 75 and 86 degrees relative to the bottom wall of
the meat tray.
16. The trim apparatus as defined in claim 14 wherein the corner
projections have curved corner surfaces with an arc of greater than
90 degrees about a center of curvature.
Description
TECHNICAL FIELD
[0001] This invention pertains to thermal plastic expanded foam
meat trays and methods and apparatus for trimming the meat trays
from an expanded foam web.
BACKGROUND OF THE INVENTION
[0002] Often it is necessary, after food is placed in the meat
tray, to cover the top opening with a plastic or metal film having
an airtight seal all around the top opening flange to help preserve
the food, minimize oxidation and prevent food contamination while
the food is being transported and presented for sale. Thus it is
very important that top flanges of the thermal plastic expanded
foam meat trays be accurately trimmed to provide a uniform seal
surface on the flange to receive the plastic or metal film.
SUMMARY OF THE INVENTION
[0003] An apparatus and method are provided for forming a thermal
plastic expanded foam rectangular meat tray that is trimmed from a
thermal plastic expanded foam web. The thermal plastic expanded
foam is a thermoformable plastic material such as a polystyrene
foam. The meat tray includes alignment features that accurately
align the meat tray when severing the formed meat tray from a web
of thermal plastic expanded foam material.
[0004] According to one aspect, a thermal plastic expanded foam
rectangular meat tray is configured to be trimmed from a thermal
plastic expanded foam web. The meat tray includes a substantially
rectangular bottom wall, and side walls. The side walls extend
upward and outward from the bottom wall integrally interconnected
to each other at four corners. Each of the side walls has an
inclined lower section and an upper section that extends upwardly
and terminating in a lip that extends outward around the periphery
of the tray. The upper wall section has internal inclined corner
surfaces extending upward and outward to the lip at the four
corners. Each of the corner surfaces is specifically provided to
receive an internal complementary mating corner alignment fixture
in order to maintain the tray accurately aligned at the corners as
the tray is being trimmed from the thermal plastic expanded foam
web.
[0005] According to another aspect, a process is provided for
severing uncut thermoformed rectangular meat trays with precisely
trimmed lips from a thermal plastic expanded foam web in which each
meat tray has diagonally opposing steeply inclined interior corner
surfaces. The process includes: (a) moving the web to place at
least one of the rectangular meat trays between a rectangular meat
tray punch and a rectangular meat tray die, in which the
rectangular punch has an alignment fixture thereon with
complementary steeply inclined exterior alignment surfaces for
engaging the steeply inclined interior corner surfaces of the meat
trays; (b) moving the punch and die relative to each other a first
distance to insert the alignment fixture within the meat tray with
the alignment surfaces engaging the diametrically opposed interior
corner surfaces of the meat tray to accurately align the meat tray
longitudinally, laterally and angularly with respect to the punch
and die; and (c) while maintaining the alignment surfaces in
engagement with the corner surfaces, moving the punch and die
relative to each other a second distance to sever the meat tray
from the web with a precisely formed lip about its periphery.
[0006] According to yet another aspect, the trim apparatus is
provided for severing uncut thermal formed rectangular meat trays
to produce precisely trimmed lips when removing the trays from a
thermal plastic expanded foam web. Each meat tray has diagonally
opposing steeply inclined interior corner surfaces. The trim
apparatus includes a rectangular meat tray die, a rectangular meat
tray punch, an alignment fixture, a placement means for placing an
untrimmed meat tray between the punch and the die, and drive means
operatively connected to the die and punch. The rectangular meat
tray punch opposes the rectangular meat tray die. The alignment
fixture is mounted on the punch having complementary exterior
alignment corner surfaces thereon for engaging the steeply inclined
interior corner surfaces of the meat tray to maintain the meat tray
in alignment in longitudinal, lateral and angular directions. The
drive means are operatively connected to the die and punch for
moving the punch and die relative to each other a first distance in
order to move the alignment fixture into the meat tray with the
exterior alignment corner surfaces engaging the steeply inclined
interior corner surfaces of the meat tray to accurately align the
meat tray in the longitudinal, lateral, and angular directions. The
drive means are further operatively connected to the die and punch
for moving a second distance to accurately trim the meat tray from
the web with a precisely formed lip about its periphery while the
fixture corner surfaces are engaging the tray corner surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Preferred embodiments of the invention are described below
with reference to the following accompanying drawings.
[0008] FIG. 1 is schematic view of a thermal expanded foam web
passing by a preheat station, a meat tray forming station, and a
trim press station for forming unique rectangular-shaped meat trays
and separating the formed meat trays from the web;
[0009] FIG. 2 is an isometric view of a preferred embodiment of the
unique meat tray;
[0010] FIG. 3 is a top view of the meat tray shown in FIG. 2;
[0011] FIG. 4 is a side view of the meat tray shown in FIG. 3;
[0012] FIG. 5 is a fragmentary vertical cross-sectional view taken
along line 5-5 in FIG. 3;
[0013] FIG. 6 is a fragmentary vertical cross-sectional view taken
along line 6-6 in FIG. 3;
[0014] FIG. 7 is an enlarged fragmentary top view taken along
circle line 7 in FIG. 3 showing a corner of the meat tray;
[0015] FIG. 8 is an fragmentary isometric view of a punch platen
used at the trim station, along with other components, for
separating formed trays from the web;
[0016] FIG. 9 is a fragmentary isometric view of a female die
platen used in conjunction with the punch platen shown in FIG. 8
for separating formed meat trays from the web;
[0017] FIG. 10 is a fragmentary vertical cross-sectional view
through opposing punch platen and female die platen showing
vertical movement of the punch platen to trim one of the meat trays
from the web;
[0018] FIG. 11 is a horizontal cross-sectional view taken along
line 11-11 in FIG. 10 emphasizing an alignment fixture mounted on
the punch platen for aligning the meat tray as the tray is being
trimmed and separated from the web; and
[0019] FIG. 12 is a vertical cross-sectional view taken along line
12-12 in FIG. 11 illustrating the insertion of the alignment
fixture into an upper portion of meat tray to align the meat tray
prior to the tray being trimmed from the web.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] This disclosure of the invention is submitted in furtherance
of the constitutional purposes of the U.S. Patent Laws "to promote
the progress of science and useful arts" (Article 1, Section
8).
[0021] FIG. 1 illustrates a thermal plastic expanded foam web or
sheet 8 passing through a pre-heat station 52 and a meat tray
forming station 54 for forming meat trays 10. The web 8 with the
formed trays then moves to a meat tray trim station 56 for
separating the formed meat trays 10 from the web 8 and then past a
web comminuting station 57 for shredding the remaining web after
the meat trays 10 have been removed from the web 8. The web 8 is
incrementally fed to the meat tray trims station 56 by a conveying
means generally designated by the numeral 58 in FIG. 1. Such a
conveying means 58 includes drive motors 60 and 62 that drive web
rollers (not shown) for moving the web 8. The motors 60 and 62 are
controlled by a servo motor controller 64. Such a conveying means
is shown in more detail in U.S. Pat. No. 6,067,886 granted to the
present Applicant on May 30, 2000 and entitled "Machine Trim Press
Having Counterbalance Features". Such patent is incorporated herein
by reference.
[0022] FIGS. 2-7 illustrate a preferred embodiment of the unique
rectangular-shaped meat tray 10. The expanded foam meat tray 10 has
a rectangular bottom wall 12 with long side walls 14 and 16 that
are interconnected by short end or side walls 18 and 24. The short
side wall 18 is formed integrally with the long side walls 14 and
16 at curved wall corners 20 and 22. The short side wall 24 is
formed integrally with the long side walls 14 and 16 at curved wall
corners 26 and 28. The side walls 14, 16, 18 and 24 extend upward
and outward from the bottom wall 12 to a peripheral outwardly
extending flange or lip 30. The lip 30 has an upper surface 32 that
forms a seal surface for enabling films to be laid over the tray
and affixed to the surface 32 to provide airtight seal protection
to the food product placed in the tray 10. The side walls 14, 16,
18 and 24 extend upward and outward at an obtuse angle "A" of
between 110 degrees and 140 degrees relative to the bottom wall 12
(FIGS. 5 and 6). The side walls 14, 16, 18 and 24 have lower wall
sections 34 that extend upward and outward to upper wall sections
36. The upper wall section 36 extends upward and outward from an
external nesting shoulder 40 to the peripheral lip 30. The upper
wall sections 36 have a series of internal stepped ribs 38 formed
therein to provide strength and rigidity to minimize bulging of the
side walls.
[0023] Importantly, each of the wall corners 20, 22, 26, and 28 has
an internal inclined alignment corner surface 42 formed therein
extending downwardly from the inside of the lip 30 toward the
bottom wall 12 for receiving a complementary surface of an
alignment fixture to maintain the meat tray 10 in alignment, in the
longitudinal, lateral, diagonal and angular directions, while the
tray 10 is being precisely trimmed from the web 8 at the trimming
station 56. Preferably the alignment corner surfaces 42 extend
downward at a steep obtuse angle "B" of between 94 degrees and 105
degrees relative to the bottom wall 12 (FIGS. 4 and 5). Preferably
angle "B" is between 94 degrees and 100 degrees. Preferably the
alignment corner surfaces 42 extend downward from the lip 30, on
the inside of the upper wall sections 36, eliminating part or all
of one or more ribs 38 in the corners 20, 22, 26, and 28.
[0024] Preferably the alignment corner surfaces 42 are convex
curved as seen in the top views FIGS. 3 and 7. Preferably the
alignment corner surfaces are curved in an arc of more than 90
degrees, but less than 180 degrees, with a radius of curvature 44
about a center of curvature 46 (FIG. 7). Preferably each alignment
corner surface 42 is conical in shape having a wide curved arc in
the horizontal direction and a steep inclined shallow conical wall
element in the vertical direction.
[0025] A trim press is located at the trimming station 54 for
trimming and separating one or more meat trays 10 at a time from
the web 8. The reader is directed to previously mentioned U.S. Pat.
No. 6,067,886 for many of the details of such a trim press. For
purpose of brevity the above-mentioned U.S. Pat. No. 6,067,886 is
incorporated by reference should the reader desire such detail. For
the purpose of this application, the important features are a
unique punch platen 70 and a complementary die platen 72, which are
described in more detail with reference to FIGS. 8-12.
[0026] The punch platen 70 has a plurality (row) of rectangular
male punch elements of plates 74 mounted thereon. Each punch plate
74 has a generally rectangular peripheral cutting edge 76
surrounding a front face surface 78.
[0027] The die platen 72 has a plurality (row) of female die
elements 80 that are complementary to the punch plates 74. Each of
the die elements 80 has an internal cutting edge 81 surrounding a
generally rectangular pass-through opening 82.
[0028] Importantly, each of the male punch plates 74 has a meat
tray alignment fixture 84 projecting forward of the front face
surface 78 that moves in conjunction with a respective plate 74 for
initially entering the meat tray 10 and aligning the meat tray 10
longitudinally, laterally and angularly with respect to the
respective punch plate 74 and die element 82. As the fixture 84
enters the rectangular meat tray 10 it engages the alignment corner
surfaces 42 to stretch at least the upper section 36 of the meat
tray in the diagonal directions as well as in the longitudinal,
lateral and angular directions to enable the lip 30 to be trimmed
precisely as the cutting edges 76 and 81 sever the meat tray from
the web 8.
[0029] Preferably, each alignment fixture 84 has a thin, generally
rectangular-shaped plate or spider body 86 with an enlarged central
void or opening 88. Enlarged corner elements 90 extend outward at
the corners. Each element 90 has a peripheral exterior side surface
92 complementary to the internal corner alignment surface 42 of the
meat tray 10 for engaging the internal corner alignment surface 42
as the fixture 84 enters the top opening of the meat tray 10.
Preferably each of the exterior side surfaces 92 is steeply
inclined at an acute angle "C" of between 75 degrees and 86 degrees
relative to the bottom wall of the meat tray (FIG. 12). More
preferably the acute angle "C" is between 80 degrees and 86
degrees. Also preferably each of the exterior side surfaces 92 has
an arc in the horizontal direction of greater than 90 degrees.
[0030] The alignment fixture 84 is mounted to the punch plate 74 by
at least two diagonally spaced support bolts 94. The bolts 94 have
bolt shafts 96 slidably mounted in a countersunk bore 98 formed in
the punch plate 74 to enable the thin plate 86 to move from an
extended position to a retracted position relative to the front
face surface 78. Each bolt 94 has an outer end 99 that is threaded
in a complementary threaded aperture in the thin plate 86.
[0031] The alignment fixture 84 further includes guide rods 100
that are mounted in the face surface 78 and extend outward
projecting through guide apertures 102 in the thin plate 86 to
maintain the fixture 84 aligned with the punch plates 74 as the
thin plate 86 moves between the extended position and the retracted
position. Corner coil springs 108 are mounted between the alignment
fixture 84 and the punch plate 74 to bias the alignment fixture 84
to the extended position. The corner coil springs 108 are seated in
shallow spring cavities 104 and 106 formed respectively in the
punch plate 74 and the thin plate 86.
[0032] The punch platen 70 is reciprocated to and from the die
platen 72 by a punch drive 110. See the above-identified U.S. Pat.
No. 6,067,886 for specific structural details. As the punch platen
70 is moved a first distance toward the die platen 72, the
alignment fixture 84 is moved into the top opening of the meat tray
(FIG. 12) with the exterior side surfaces 92 engaging the interior
corner alignment surfaces 42 of the meat tray to accurately align
the meat tray 10 relative to the cutting edges 76 and 81. As
previously mentioned, the alignment fixture 84 aligns the meat tray
10 diagonally between the corners, as well as longitudinally,
laterally and angularly relative to the cutting edges 76 and
81.
[0033] Further movement of the punch platen 70 moves the aligned
meat tray 10 into the die opening 82 with the lip 30 engaging the
die element 80, causing the alignment fixture 84 to move from the
extended position to the retracted position while maintaining
alignment, and brings the cutting edges 76 and 81 into cutting
relationship with the web 8 to trim the lip 30 and sever the meat
tray from the web 8. Once the trays 10 are severed from the web 8,
the coil springs 108 bias the alignment fixture 184 outward from
the plate 74, pushing the severed meat tray 10 into the
pass-through opening 82 and onto an exit conveyer (not shown).
[0034] In compliance with the statute, the invention has been
described in language more or less specific as to structural and
methodical features. It is to be understood, however, that the
invention is not limited to the specific features shown and
described, since the means herein disclosed comprise preferred
forms of putting the invention into effect. The invention is,
therefore, claimed in any of its forms or modifications within the
proper scope of the appended claims appropriately interpreted in
accordance with the doctrine of equivalents.
* * * * *