U.S. patent number 3,675,812 [Application Number 05/036,917] was granted by the patent office on 1972-07-11 for plastic cover with hinged closure and molding dies therefor.
This patent grant is currently assigned to J. L. Clark Manufacturing Co.. Invention is credited to John A. Foster.
United States Patent |
3,675,812 |
Foster |
July 11, 1972 |
PLASTIC COVER WITH HINGED CLOSURE AND MOLDING DIES THEREFOR
Abstract
The disclosed plastic cover is similar to and an improvement on
that shown in U.S. Pat. No. 3,095,995 by virtue of the projection
of the peripheral edge of the hinged closure flap laterally and
outwardly beyond the full length of an arcuate sealing rib and the
opposed wall of the dispensing opening with the outer face of the
rib making an acute included angle with the under surface of the
flap and the inner rib surface disposed substantially parallel to
the path of separation of the die surfaces in which the flap and
rib are molded. The molding of such a cover construction is made
possible by a unique die assembly which permits the hinged flap and
rib to be disposed at a substantial obtuse included angle relative
to the dispensing opening during the molding of the cover.
Inventors: |
Foster; John A. (Rockford,
IL) |
Assignee: |
J. L. Clark Manufacturing Co.
(Rockford, IL)
|
Family
ID: |
21891386 |
Appl.
No.: |
05/036,917 |
Filed: |
May 13, 1970 |
Current U.S.
Class: |
220/835; 222/480;
222/565; 220/200; 220/837 |
Current CPC
Class: |
B65D
47/0847 (20130101) |
Current International
Class: |
B65D
47/08 (20060101); B65d 043/16 (); B65d
083/06 () |
Field of
Search: |
;220/31R,31S,60
;222/153,480,565 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lowrance; George E.
Claims
I claim:
1. A single piece container closure of molded resilient plastic
having, in combination, a generally flat top surface defining a
dispensing opening of generally segmental shape and having a
straight edge along one side, the opposite side edge of the opening
being defined by a curved upright wall merging at its ends with the
outer ends of said straight edge, a thin flap molded integrally
with said straight edge so as to form a hinge along said straight
edge permitting upward swinging of the flap from a closed position
covering said opening and in which the peripheral edge portion of
the flap abuts against said top surface to close said opening and
overlaps the edge thereof all around the opening between the ends
of said hinge, a radially flexible rib of narrow width and of the
same peripheral contour and length as said wall depending from the
underside of said flap around the full periphery thereof between
the ends of said hinge and adapted to telescope with a tight
continuous interference fit and seal around the full periphery of
said curved wall as the flap is swung to said closed position, such
tight fitting and sealing of said rib against said wall being
achieved by virtue of the outer peripheral surface of said rib,
near the free edge and over substantially the full depth of the
rib, making an acute included angle with the surrounding underside
of the flap so that said rib, beginning at the free edge thereof,
is bent inwardly during entry into said opening and telescoping
within said wall.
2. A molded container cover as defined in claim 1 in which said
acute included angle is of such magnitude as to permit the mold
parts, by which the surfaces defining such angle are formed, to be
separated by relative bodily movement along a straight line
perpendicular to the plane of said opening.
3. A molded container cover as defined in claim 1 in which said
acute included angle is such that the full peripheral length of the
curved outer surface of said flap rib is vertically disposed when
said flap is disposed at a predetermined obtuse molding angle
relative to the plane of said opening whereby to permit, without
substantial interference, vertical separation of the die surfaces
by which the surface of said opening wall and the surfaces of said
rib are formed.
4. A molded container cover as defined in claim 1 in which the
magnitude of said acute angle is approximately 80.degree..
5. A molded cover as defined in claim 1 in which the elements of
the inner surface of said rib are substantially vertical when said
flap is open to its molding position.
6. A molded container cover as defined in claim 1 in which the free
edge of said rib interlocks with the free edge portion of said
curved wall as the cover is swung to closed position thus holding
the cover releasably against said top surface.
7. A molded container cover as defined in claim 6 in which the
curved wall of said dispensing opening is disposed substantially
normal to the plane of the opening and is formed with at least one
shallow and inwardly projecting bead disposed intermediate the
upper and lower edges of said curved wall of said dispensing
opening and acting as the flap approaches closed position to
compress the passing rib and snap in beneath the rib and hold the
flap in said closed position against said top surface.
8. A single piece container closure of molded resilient plastic
having, in combination, a generally flat top defining a dispensing
opening of generally segmental shape and having a straight edge
along one side, the opposite side edge of the opening being defined
by a curved upright wall merging at its ends with the outer ends of
said straight edge, a thin flap molded integrally with said
straight edge so as to form a hinge along said straight edge
permitting upward swinging of the flap from a closed position
covering said opening and in which the peripheral edge portion of
the flap abuts against said top surface to close said opening and
overlaps the edge thereof all around the opening between the ends
of said hinge, a radially flexible rib of the same peripheral
contour and length as said wall depending from the underside of
said flap around the full periphery thereof between the ends of
said hinge and adapted to telescope with tight continuous
interference around the full periphery of said curved wall as the
flap is swung to said closed position, said rib being of relatively
narrow radial width and coacting with said curved wall to telescope
within said opening with a tight fit, and lugs formed at the ends
of said curved wall and having surfaces inclined downwardly from
the plane of the cover top and away from said hinge, the ends of
said flap rib being shaped to abut said lug surfaces as said flap
reaches closed position.
9. A molded container cover as defined in claim 8 including a bead
of narrow width molded on one of the opposed inclined surfaces of
said lugs and rib ends and adapted to yield more readily as said
flap becomes closed whereby to increase the effectiveness of the
seal at the ends of the flap rib.
10. A molded container cover as defined in claim 9 including a
lateral and outward extension of said sealing bead at the lower
portion thereof, such extension projecting into tight abutment at
its end with the opposed surface of the wall of said dispensing
opening at the junction thereof with said hinge.
Description
BACKGROUND OF T INVENTION
The present invention relates to a plastic cover of the general
construction disclosed in my prior U.S. Pat. No. 3,095,995
including a hinged closure flap swingable into and out of a top
recess to close or uncover a dispensing opening defined by a
straight edge along the hinge and an opposed arcuate wall which
receives and telescopes with an arcuate rib depending from the
underside of the flap to provide a tight seal around the periphery
of the opening when the flap is fully closed.
SUMMARY OF THE INVENTION
The present invention improves on the patented construction by
making the arcuate sealing rib smaller than the closure flap all
around the latter between the ends of the flap hinge so that, in
the closed position of the flap, the peripheral edge portion
thereof overlies and abuts against the top surface surrounding the
opening. A seal of increased effectiveness is formed by the free
edge of the rib engaging the opposed and somewhat yieldable wall on
the container top.
The foregoing objective is achieved by inclining the outer and
inner surfaces of the flap at angles such that in the molding of
the cover these surfaces are disposed substantially normal to the
path of separation of the molding dies and therefore may be molded
with a contour required for achieving the desired sealing action
all around the dispensing opening.
Another object is to facilitate such molding and tight sealing by a
novel shaping of the ends of the sealing rib and surfaces abutted
thereby in the closed position of the flap.
A further object is to provide, in the other end portion of the
cover, separate and novelly constructed sifter openings covered by
a flap which may be molded in the same inclined position as the
spoon hole flap.
The invention also resides in the novel construction of the die
assembly for molding of the cover with the spoon hole and sifter
flaps inclined at the obtuse angle referred to above while
permitting easy removal of the cover after cooling by movement
along the axis of the die assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary perspective view of a spice can having a
cover embodying the novel features of the present invention.
FIG. 2 is a perspective view of the cover with the closure flap in
the open position in which it is molded.
FIGS. 3 and 4 are sections taken along the lines 3--3 and 4--4 of
FIG. 1.
FIG. 5 is a section taken along the line 5--5 of FIG. 2 but with
the closure flap in closed position.
FIG. 6 is a section taken along the line 6--6 of FIG. 2.
FIGS. 7 and 8 are sections taken along the line 7--7 of FIG. 6 with
the closure flap in open and closed positions.
FIGS. 9 and 10 are fragmentary sections taken along the lines 9--9
and 10--10 of FIG. 8.
FIG. 11 is a plan view of FIG. 2.
FIG. 12 is a fragmentary section taken along the line 12--12 of
FIG. 11.
FIG. 13 is a view similar to FIG. 2 showing a modified form of the
cover.
FIG. 14 is a fragmentary section taken along the line 14--14 of
FIG. 12.
FIGS. 15 and 16 are perspective views similar to FIGS. 1 and 2
showing another modification.
FIG. 17 is a section taken along the line 17--17 of FIG. 15.
FIGS. 18 and 19 are fragmentary diametrical sections of a die
assembly for molding the plastic closure shown in FIGS. 1 to
14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to the form shown in FIGS. 1 to 12, the invention
is incorporated in a container for spices or like materials
comprising a single piece generally flat and rectangular cover 20
of molded resilient plastic such as polyethylene or polypropylene
having a depending peripheral flange 21 telescoped over and
interlocked as shown in FIGS. 3 to 5 with a hem 22 defining the
open end or lip of a tubular sheet metal body 23. In one end
portion of the cover is a laterally elongated spoon hole 24 defined
by a peripherally continuous skirt 19 depending a short distance
from the underside of the cover to provide a flat and straight wall
25, connecting parallel side walls 27, and an arcuate wall 26
defining the front edge of the spoon hole 24. The walls 25 and 26
are spaced inwardly from the long sides of the flange 21 and,
together with the latter and depending webs including 17 and 18,
impart the desired rigidity to the cover while permitting the use
of a minimum volume of plastic. The upper edges of walls 26 and 27
together with the flap top area 28 surrounding these walls are
disposed somewhat below the level of the top surface 29 of the
cover. A shallow recess is thus formed around the dispensing
opening 24 for receiving and seating a thin and flat closure flap
30 joined along a thinned section 31 (FIGS. 2 and 4) with the upper
edge of the straight wall 25 and forming therewith a hinge for
upward swinging of the flap as shown in FIGS. 2 and 6 to uncover
the opening 24 or downwardly swinging into the recess and against
the bottom 28 thereof.
Between the ends of the hinge, the peripheral edge of the flap may
be of any peripheral shape and matches that of the wall of the
recess 28 so that the cover fits closely therein and is
substantially flush with the top surface 29 when the flap is in
closed position (FIG. 1). Herein, the edge portions 32 of the flap
extending normal to the ends of the hinge are straight and parallel
and merge with straight portions 33 which converge outwardly and
terminate at a finger tab 34. Below the outer end of the latter,
the top of the cover is recessed deeper as indicated at 35 to
provide a thumb hole 36 to facilitate gripping and upward swinging
of the flap.
To seal the opening 24 tightly when the flap is closed, a narrow
rib 37 of the same curvature as the opening wall 26, 27 but
slightly smaller than this wall is molded integral with and depends
from the underside of the flap. The rib extends around the full
arcuate length of these walls and terminates at the hinge 31 in
ends 38. In accordance with one aspect of the present invention,
the ends 38 of the adjacent portions 39 of the rib 37 are spaced
short distances inwardly and along the hinge from the side edges 32
of the flap 30, and the rib is shaped and dimensioned accurately so
that it will fit closely within and around the full lengths of the
walls 26, 27. To these ends, the rib is of substantially the same
depth as the skirt wall 26, is somewhat thicker and correspondingly
less yieldable than the skirt 19, and preferably tapers somewhat
toward its free edge 41 as shown in FIGS. 6 and 12. The outer
surface 40 of the arcuate portion of the rib 37 is disposed at an
acute included angle a and the inner surface 40.sup.a is disposed
at an obtuse angle c (FIG. 6) relative to the underside of the
flap. The magnitude of these angles, 80.degree. for a and
120.degree. for c in the present instance, is such that, by
disposing the mold cavity in which the flap is formed at the proper
obtuse angle b, about 150.degree., (FIG. 18) relative to the plane
of the cover, the rib surfaces 40 and 40.sup.a and all of the
internal surfaces defining and extending around the hole 24 will be
exposed and disposed vertically and thus capable of being molded to
provide the improved seal around the spoon hole when the flap is in
closed position.
With the rib thus constructed, as above described, it will be
apparent that each successive arc of the rib edge 41 will be
pressed inwardly a slight amount as it passes and enters the upper
edge of the upright hole walls beginning at the ends 27 and
progressing around the wall 26 to the center thereof as the flap
becomes fully closed. Preferably, the skirt 19 is somewhat thinner
than the flap rib and therefore more yieldable than the rib and
near its free edge tapers to a relatively thin edge 42. Also, the
skirt surfaces 26 and 27 are inclined somewhat inwardly and
downwardly as indicated at 26.sup.a and 27.sup.a (FIGS. 6 and 8)
and are disposed at a radii enough shorter than that of the edge 41
of the flap rib 37 to ensure some outward bending of the skirt edge
42 as the flap approaches the closed position.
Because of the resiliency of the plastic and the corresponding
shaping and positioning of the skirt 19 and the rib 37 as above
described, the lower edge portions thereof will yield laterally as
needed in order to allow full telescoping of the two as the flap
becomes fully closed. By virtue of the inclining of the surface 26
and the increased yieldability of the lower edge portion of the
skirt, the edge 42 of the latter is left compressed tightly against
the lower edge of the rib as shown in FIGS. 4, 8 and 12. A tight
seal is thus formed all around the flap rib.
To hold the flap securely in closed position, one or more nibs or,
in this instance, two arcuate and horizontally disposed beads 45
are formed around the wall 26 of the skirt 19 between the upper and
lower edges thereof and project a few thousandths of an inch into
the path of the free edge 41 of the rib 37. By yielding of beads
and the rib and skirt, the rib edge passes the beads and snaps in
beneath the same as shown in FIG. 12 when the flap reaches the
fully closed position.
To enable the cover with the flap and rib 37 angularly related as
above described to be molded as a single piece and the congealed
cover to be removed from the molding as a single piece and the
dies, the ends 38 of the rib must be disposed, during the molding,
at least at a right angle relative to the plane of the dispensing
opening 24. This means that in the closed position of the flap, the
ends 38 will be disposed at an angle to the plane of the flap back
wall 25 of the dispensing opening 24. Leakage of finely powdered
material out of the container and around the ends 38 of the rib
when the flap is closed is prevented by forming in the molding
operation lugs 46 at opposite ends of the wall 25 with the surfaces
47 inclined downwardly and into the dispensing opening for abutment
with the rib ends 38 when the flap is fully closed. Since the
inclined surfaces of such lugs face upwardly, they may be formed in
the die assembly (FIG. 18) in which the flap including the rib 37
is molded.
To insure more effective sealing at the rib ends 38, shallow and
narrow beads 48 are formed along the tops of the inclines 47 for
abutment with and compression by the rib ends 38 as the flap
reaches its closed position. The effectiveness of the seal is
further increased by extending the beads 48 laterally at the lower
ends as indicated at 49 in FIGS. 7, 8 and 10. The end 50 of this
extension is thus positioned to come into abutment with and be
compressed tightly against the opposed wall 27 of the skirt 19 as
the flap reaches fully closed position.
Construction of the flap 30 with a sealing rib 37 having parallel
end portions 39 as above described is desirable in order to make
the opening 24 and the wall 25 thereof wide enough to receive a
conventional teaspoon for removing the container contents. For
larger size covers such as shown in FIGS. 13 and 14, the wall 26 of
the spoon hole may be curved all the way to the straight wall 25,
the rib 37 being of arcuate curvature throughout its peripheral
length as shown in FIG. 13. As before, the ends 38 of the rib 37
are disposed at no greater than a right angle relative to the
dispensing opening in the position in which the flap 30 is molded.
As in the construction first described and as the flap reaches
closed position, the end portions of the flap rib 37 telescope
closely within the wall 26 defining the opening 24, and the rib
ends 38 come into tight sealing abutment with shallow beads 48
upstanding from the inclined surfaces of lugs.
In another of its aspects, the present invention contemplates the
novel construction of a die assembly which permits the formation in
conventional plastic molding procedures of the flap 30 and rib 37
and the rib ends 38 angularly positioned relative to each other as
described above. This may be accomplished in a multiple part
assembly having a fixed platen 50 and a platen 51 movable forth and
back along a path indicated by the arrows between closed and open
positions shown in FIGS. 18 and 19. The cavity 52 for shaping the
upper and lower surfaces of the flap 30 is disposed during the
molding at the obtuse angle b relative to the cavity in which the
other parts of the cover including the flange 21 and the skirt 19
are formed. For molding the cover above described, the die assembly
comprises four plates 55 to 58 disposed between the platens 50, 51,
supported and guided for movements along the cover axis by lost
motion connections including annular series of screws 59 and 60 and
urged apart by compression springs 62 and 63, which are compressed
in the closed position of the die assembly shown in FIG. 18.
Opposed surfaces 53 and 54 on the plates 55 and 56 define the
cavity 52 in which the flap 30 is molded while opposed surfaces 64,
65 and 66 of the plates 55, 56 and 57 form the cavity for molding
the remainder of the cover including the flange 21 which is formed
in the plate 57. In accordance with conventional molding practice,
molten plastic for forming the cover is injected through a radially
extending passage 67 defined by radially extending grooves in the
opposed surfaces of the plates 56, 57, the inner end of the passage
leading to the cavities through a small hole 68. The plastic
congealing in this hole and the passage is broken away from the
molded cover and falls away from the same when the die plates are
separated, this being in accordance with conventional molding
practice.
After injection of molten plastic into and filling the mold cavity,
the platen 51 is moved outwardly and away from the fixed platen 50
and to the fully open position shown in FIG. 19. In the initial
part of this movement, the plate 56 is separated by the springs 62
from the plate 55 and to the position shown in dotted outline in
FIG. 19, the flap 30 being swung inwardly about the edge 69 of the
plate 56 and against the side 71 of the plate 55. In this position,
the flap is freed for withdrawal through the plate 56 and to the
position shown in dot-dash outline as the platen 51 is further
retracted. At this time, the flange 21 is still interlocked with
the plate 57 after the lost motion provided by the screws 60 has
been taken up as shown in dot-dash outline in FIG. 19.
As the retraction of the movable platen 51 continues to the
position shown in full at the right in FIG. 19, a plate 72 carrying
parallel ejector pins 72.sup.a comes into abutment with a stop 73
so that, in the final movement of the platen, the molded and then
solidified plastic cover is formed off from the formations on the
die plate 57 which shape the cover flange 21. The molded cover is
thus moved away from the die plate 57 as shown in full in FIG. 19
and is free to fall downwardly and out of the die assembly.
Thereafter, the platen 51 is moved reversely to close the die
assembly (FIG. 18) preparatory to another cover forming cycle.
The present invention also contemplates the provision of a series
of sifter holes 75 and 76 at the end of the cover opposite the
spoon hole 24 and the closure of such holes by projections 77 and
78 formed on the underside of a flap 79 molded in an inclined
position (FIG. 2) at the same time as the flap 30 and swingable
about an extension of the axis of the latter flap. The flap 79 is
flat and rectangular and is swingable down against a surface 81
which is raised to locate the top of the flap when closed (FIG. 1)
flush with that of the flap 30.
The holes 75 are arranged in parallel rows along the surface 81
with one intermediate hole 76 centered and located near the outer
end of this surface. Frustoconical surfaces 82 at the upper ends of
the holes guide the entry of the cylindrical free ends of the
projections 77, 78 and provide for seating of complemental surfaces
83 of the projections when the flap is closed, there being small
clearance 79.sup.a between the flap and the top 81 in the closed
position of the flap as shown in FIG. 5. Progressing outwardly
along the flap and away from its hinge, the projections 77, 78 are
made of increasing lengths as shown in FIG. 5, thus allowing for
easy entry of all of the projections during closing of the flap and
more secure holding of the closed flap by the longer projections.
Also, the outer side of the outermost projection 78 is undercut as
indicated at 84 so as to interengage with the edge 85 of the hole
76 with a snap overcenter action as the flap reaches closed
position.
The flap 79 is somewhat longer than the top surface 81 so that its
free end projects beyond this surface thus leaving a recess 86
(FIG. 1) for facilitating gripping of the flap for lifting thereof.
This recess is confined to the free end of the flap by forming a
rib 87 (FIG. 2) along the outer edge of the flap with the end
portion 88 thereof curved around the corner 89 of the surface 81.
The space between the flap and the top surface 35 of the cover is
thus closed effectually thereby minimizing the danger of the flap
being engaged and swung open in the course of handling and
shipment.
The sifter flap constructed as above described may be molded at the
same time as the flap 30 and in a four part die assembly similar to
that shown in FIGS. 18 and 19 and with the cavity for forming the
flap, its hinge, and the projections 77, 78 disposed about in the
position shown in FIG. 2 and its hinge alined with the hinge of the
flap 30. Although the sides of the projections nearest the hinge
will face downwardly, the projections will, because of their short
length and resiliency, be released from the die part 57 in the
separation from the part 56 as shown in FIG. 19.
Closure flaps and sealing thereof as well as the molding technique
as above described may be used for other kinds of containers. In
the example illustrated in FIGS. 15-17, the parts corresponding to
those first described are indicated by the same but primed
reference numerals. In this container, the single piece cover 20'
is molded with a depending cylindrical skirt 91 having an internal
thread 92 for mating with a thread on the open end of a jar 93 or
other container. Screwing of the cover onto the jar is limited by
engagement of the jar lip with an annular abutment 94 (FIG. 17)
facing downwardly on the underside of the cover.
The top 29' of the cover and the flap 30' are semi-circular and the
thinned section 31' defining the flap hinge extends diametrically
across the cover between points 95. The surface 26' defining the
arcuate portion of the dispensing opening 24' is the inner edge of
a flange 96 turned inwardly near the upper end of the skirt as
shown in FIG. 17. The skirt 91 is extended upwardly as indicated at
97 beyond the top of this flange so as to provide a recess for
enabling another jar to be stacked on top and located laterally.
The flange 96 is shaped to provide an upwardly opening groove
97.sup.a separating the skirt extension and the outer edge of the
flap 30'. Interference with the swinging of the latter is thus
avoided.
As in the constructions above described, the entire length of the
peripheral edge of the flap 30' projects outwardly beyond the
arcuate rib 37' which depends from the underside of the flap and
telescopes tightly within the flange surface 26' in the downward
swinging of the flap to closed position. Such overhanging of the
flap edges and the spacing of the end portions of the rib inwardly
from the sides of the flap is made possible as above described by
disposing the die cavity in which the flap is molded at the obtuse
angle b (FIG. 18) and as shown in FIG. 17 so that the outer surface
40' of the rib is disposed at the acute angle a (FIG. 17) relative
to the flap. Because of this inclining, the end surfaces 38' of the
rib are correspondingly inclined and disposed relative to the plane
of the flap. To provide a seal between these ends and the ends and
the upright wall 25' along the straight edge of the opening 24',
lugs 46' are formed at the ends of the wall with downwardly and
outwardly inclined faces 47' with which the rib ends come into
sealing engagement as shown in FIG. 17 when the flap reaches fully
closed position. The opening 24' is thus closed effectually.
For use of the cover with some containers, it is desirable to stop
the hinge 31' short of the edges of the flap 30' as shown in FIGS.
15 and 16. In such a case, the sealing above described may be
achieved by extending the lugs 46' and their inclined surfaces 47'
outwardly for abutment, not only with the ends 38' of the rib 37'
but also with the ends 98 of the surface 25' which, like the ends
38' are inclined at the obtuse angle b in the molding
operation.
When an extremely tight seal around the dispensing opening is not
required, a single hold-down bead 99 may be employed. In this
instance, this bead is of short arcuate length and projects outward
from the central part of the flap rib 37' as shown in FIG. 16. As
the flap reaches closed position, this bead is compressed, as
permitted by yielding of the rib and the flange surface 26', and
allowed to pass across and snap in beneath this surface as shown in
FIG. 17.
For molding the cover shown in FIGS. 15-17, only the three plates
55, 56, and 58 above described are required, the assembly being
modified however to provide for unscrewing of the cover from the
plate 58 or, in some other conventional way, effecting removal of
the molding from the die plate in which the thread 92 is
formed.
* * * * *