U.S. patent number 3,640,668 [Application Number 04/844,305] was granted by the patent office on 1972-02-08 for reentrant forming apparatus.
This patent grant is currently assigned to Packaging Industries, Inc.. Invention is credited to Fred P. Brown, Jr., Howard A. Rohdin.
United States Patent |
3,640,668 |
Brown, Jr. , et al. |
February 8, 1972 |
REENTRANT FORMING APPARATUS
Abstract
A pair of dies engage a sheet of heat-softened foamed
polystyrene plastic at a forming station and form it into a desired
shape such as a carton. At the same station, and while the plastic
is held between the dies, a portion of the plastic protruding from
the dies is engaged on opposite sides by cooperating punches to
impart a reentrant formation to the plastic that the dies alone
could not impart. The reentrant formation facilitates releasably
latching the top and bottom portions of the completed carton in a
closed position.
Inventors: |
Brown, Jr.; Fred P.
(Centerville, MA), Rohdin; Howard A. (Waquoit, MA) |
Assignee: |
Packaging Industries, Inc.
(Hyannis, MA)
|
Family
ID: |
25292342 |
Appl.
No.: |
04/844,305 |
Filed: |
July 24, 1969 |
Current U.S.
Class: |
425/161;
425/DIG.58; 264/321; 425/317; 425/343; 425/388; 425/394 |
Current CPC
Class: |
B29C
51/34 (20130101); B29C 51/32 (20130101); B29C
51/082 (20130101); B29C 51/30 (20130101); B29C
67/0048 (20130101); B29K 2105/04 (20130101); B29K
2025/00 (20130101); B29L 2031/7168 (20130101); Y10S
425/058 (20130101) |
Current International
Class: |
B29C
51/32 (20060101); B29C 51/34 (20060101); B29C
51/30 (20060101); B29C 51/08 (20060101); B29C
67/00 (20060101); B29c 017/00 (); B29d
027/00 () |
Field of
Search: |
;18/35,19BE,19BM,19TE,19P,16.7,12PH,12TF,19R,19F,5R,5P,4B
;264/321,296 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Flint, Jr.; L. Howard
Claims
We claim:
1. In forming apparatus having a pair of dies adapted for relative
movement towards each other to impart a predetermined shape to a
blank of formable material inserted therebetween and reentrant
forming means for imparting a reentrant formation to said blank
having said predetermined shape imparted by said dies, the
improvement wherein said reentrant forming means comprises a pair
of cooperating punches and means mounting said punches for relative
movement with respect to each other, the relative movement of said
punches with respect to each other being different from the
relative movement of said dies with respect to each other and each
punch having a protruding forming portion and a recessed
counterpunch, the forming portion of each punch cooperating with
the counterpunch of the other punch.
2. In forming apparatus having a pair of dies adapted for relative
movement towards each other to impart a predetermined shape to a
blank of formable material inserted therebetween and reentrant
forming means, the improvement wherein said reentrant forming means
comprises a pair of cooperating punches and drive means for moving
said punches towards each other, each punch having a protruding
forming portion and a recessed counterpunch, the forming portion of
each punch cooperating with the counterpunch of the other punch,
and said punches being respectively movable towards each other by
said drive means in a direction different from the direction of
relative movement of said dies towards each other to impart a
double reentrant formation to material inserted therebetween.
3. Apparatus according to claim 2, wherein said drive means
includes a pair of rotatable shafts and wherein each of said pair
of punches is mounted for rotation on a different one of said
shafts, whereby said punches are pivoted upon rotation of said
shafts to impart said double reentrant formation to said
material.
4. Apparatus according to claim 3 wherein said shafts are parallel
to each other.
Description
BACKGROUND OF THE INVENTION
This invention relates to the formation of materials into a desired
shape and, more particularly, to novel and highly effective
apparatus facilitating the forming of a material in a case where it
is desired to impart a reentrant formation to the material which
cannot be imparted, for example, by the simple act of bringing
together a pair of dies on opposite sides of the material to be
formed.
While the invention has many applications, it is here disclosed
particularly as it relates to the formation of cartons from foamed
polystyrene plastic. Very desirable cartons of this general
description are disclosed and claimed in a copending application of
Rohdin Ser. No. 814,254, filed Apr. 8, 1969, for "Carton Latch
Construction," now U.S. Pat. No. 3,572,578 and very desirable
methods and apparatus that can be used generally in the formation
of cartons are disclosed and claimed in a copending application of
Fred P. Brown, Jr., Ser. No. 815,292, filed Apr. 11, 1969, for
"Method and Apparatus for Forming Containers." Both of the
above-identified applications are assigned to the assignee of the
present application.
SUMMARY OF THE INVENTION
An object of the present invention is to provide apparatus
facilitating the production of a superior carton that is extremely
inexpensive and that includes reentrant portions facilitating
latching of the carton in a closed position.
The foregoing and other objects of the invention are attained by
the provision, in a preferred embodiment thereof, of apparatus for
use with a pair of dies and means mounting the dies for relative
movement with respect to each other between an open position
facilitating accommodation therebetween of a formable material and
a closed position facilitating forming of the material at a forming
station to a predetermined shape. In accordance with the invention,
additional forming means is provided operatively associated with
the dies, or at a separate forming station, and motive means is
provided for bringing the additional forming means into cooperation
with the material for further forming the material to a desired
shape.
BRIEF DESCRIPTION OF THE DRAWING
An understanding of additional aspects of the invention may be
gained from a consideration of the following detailed description
of a representative embodiment thereof, in conjunction with the
accompanying figures of the drawing, wherein:
FIGS. 1-3 are end elevational views, partly in section, of a
representative embodiment of apparatus constructed in accordance
with the invention in three successive stages of its operation;
FIG. 4 is a fragmentary side elevational view of the apparatus of
FIGS. 1-3; and
FIG. 5 is an end elevational view, partly broken away, of a carton
produced by the apparatus of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1-4 show apparatus 10 constructed in accordance with the
invention. The apparatus 10 comprises a pair of dies 12 and 14
mounted for relative movement with respect to each other as shown
by a double-headed arrow 16 between an open position facilitating
accommodation therebetween of a formable material, as shown in FIG.
1, and a closed position, as shown in FIGS. 2 and 3, facilitating
forming of the material 18 at a forming station 20 to a
predetermined shape, including a protruding portion 22 shown in
FIG. 2.
Additional forming means 24 is provided operatively associated with
the dies 12 and 14. Motive means for the additional forming means
24 includes spur gears 26 and 27 and shafts 28 and 29,
respectively, driven by the spur gears 26 and 27 for bringing the
additional forming means 24 into cooperation with the material, as
shown in FIG. 3, for further forming the material to a desired
shape.
The additional forming means 24 comprises punch means and, more
particularly, at least one punch 30 and another punch 32 mounted at
the station 20. The punches 30 and 32 are keyed by keys 42 and 44,
respectively, to the shafts 28 and 29 on which the punches 30 and
32 are respectively mounted. The shafts 28 and 29 can be parallel
to each other so that the depth of the reentrant formations does
not vary as a function of distance along the length of the
completed carton or can be canted with respect to each other so
that the reentrant formations are deeper at one end of the carton
than at the other end. The latter embodiment provides a "zipper
effect" facilitating opening and closing of the carton. The punches
30 and 32 are mounted in spaced-apart relation to each other, and
they have respectively forming portions 34 and 36 and are paired
for cooperation with each other. The motive means including the
spur gear 26 and shaft 28 for operating the lower punch 30 and the
spur gear 27 and shaft 29 for operating the punch 32 is adapted to
move the punches 30 and 32 pivotally between a retracted position
as shown in FIG. 2 facilitating accommodation of the formable
material 18 between the forming portions 34 and 36 and an advanced
position as shown in FIG. 3 in which the forming portions 34 and 36
engage the portion 22 of the material 18, the forming portions 34
and 36 being in vertically offset relation to each other. A
counterpunch portion 38 on the punch 30 opposes the forming portion
36 on the punch 32, and, likewise, a counterpunch portion 40 on the
punch 32 opposes the forming portion 34 of the punch 30.
The reentrant formation generally designated 46 (FIG. 3) thus
formed includes an upper reentrant portion (as seen in FIG. 3) 48
and a lower reentrant portion 50. The portions 48 and 50 are both
reentrant in the sense that they could not have been made by the
dies 12 and 14, which move, as noted above, in the direction
indicated by the arrow 16 in coming together on opposite sides of
the material 18. As will be apparent, the forming portions of the
respective punches 30, 32 may be arranged, if desired, to produce
one or more holes in the material 18. In accordance with the
present invention, it is thus possible to form the reentrant
portions 48 and 50 concurrently with the principal formation
effected by the dies 12 and 14, and, moreover, at the same station.
Consequently, the formed cartons need not be passed to a separate
station for the formation of reentrant portions. However, in
certain cases the latter may be desirable, and it is within the
scope of the invention to form the reentrant portions at a separate
station by means of the novel forming apparatus 24.
Those skilled in the art will of course appreciate that reentrant
formations have important advantages in the manufacture of cartons,
such as for eggs and the like, out of foamed polystyrene and the
like, for such construction is far better able to resist accidental
opening of the cartons during stacking and so forth. In the example
illustrated in FIG. 5, the formable material 18 is formed into a
top 52 and a bottom portion 54, by the principal forming means 12,
14 and the portions 52 and 54 can be brought together and latched
in a closed position by latch means including the reentrant
portions 48 and 50 provided by the additional forming means 24. The
principles of the invention are applicable, of course, regardless
of the precise nature of the formation imparted by the main forming
means and the latter may be used to form carton trays or lids,
only, rather than complete cartons.
The formable material 18 can be expandable polystyrene foam,
biaxially oriented polystyrene sheet material, high-impact
polystyrene, a multipolymer, polypropylene, polyethylene, ABS, a
laminated construction or other thermoplastic material. In
accordance with the invention, egg cartons, cottage cheese
containers, margarine tubs, etc., may be manufactured more
efficiently, quickly, and economically than has heretofore been
possible.
It is within the scope of the invention to employ gripping members
for gripping and advancing the material through a machine that
performs other steps in addition to the forming steps. For example,
preheating may be effected in order to facilitate thermoforming,
and also printing and the usual trimming and the blanking may be
effected in order to produce a neat and commercially desirable
finished product.
Many modifications of the representative embodiment described
herein will readily occur to those skilled in the art. For example,
the means effecting the reentrant formations need not move
pivotally; such means can be made to execute other kinds of
movement, including rectilinear or curvilinear reciprocating
movement. Moreover, the forming portions of the punches 30, 32 may
be located at various positions along their lengths, dependent upon
where the desired formation is to be produced in the carton. This
may be adjacent the edge or substantially inwardly thereof. The
invention is to be construed as including all of the embodiments
thereof within the scope of the appended claims.
* * * * *