Contractable closure member

The invention relates to a contractable closure member for sealing an open-ended container. The closure member comprises a top wall formed of a rigid material and an elastic bottom wall formed of a flexible material and having an upwardly extending continuous side wall. The side wall has a seal formed integral therewith, and this wall is securable to the top wall whereby the bottom wall is held in spaced relationship with the top wall. A retracting lever is pivotally secured in the top wall and has an engagement end and a pusher end. The pusher end is arcuately displaceable against a central portion of the bottom wall to distend the bottom wall whereby the side wall will be drawn inwardly to remove sealing pressure when positioned for sealing engagement in an open-ended container.

BACKGROUND OF INVENTION 
(a) Field of the Invention 
This invention relates to an improved contractable closure member for 
sealing open-ended containers. 
(b) Description of Prior Art 
Contractable closure members for sealing open-ended containers are known. 
However, those known closure members either have an actuable element 
protruding from the top wall of the cover and are restricted to 
circular-shaped closures in order to obtain substantially uniform radial 
stretching of the closure bottom wall. 
SUMMARY OF INVENTION 
It is a feature of the present invention to provide a contractable closure 
member of an improved construction which provides advantages over known 
contractable closure members. 
It is a further feature of the present invention to provide a contractable 
closure member wherein the top wall thereof is substantially flat thereby 
permitting stacking of articles onto the cover and permitting a container 
having the cover to be stored in an area of smaller height than with prior 
art closure members. Also, the closure member being of substantially 
reduced thickness requires less space for storage and shipping. 
A further feature of the present invention is to provide a contractable 
closure member which may have various contour configurations such as 
circular, rectangular, square, rectangular with rounded corners, etc. 
A further feature of the present invention is to provide a contractable 
closure member requiring single-hand operation and which is easy to 
dismantle and clean. 
A further feature of the present invention is to provide a contractable 
closure member having a retractable lever which is displaceable to two 
distinct positions when used with an open-ended container, thereby 
indicating that the closure member is in sealing engagement or in a 
non-sealing engagement with the container. 
A further feature of the present invention is to provide a contractable 
closure member wherein the bottom elastic wall is constructed such as to 
coact with the retracting lever such as to permit substantially uniform 
stretching thereof when distended. 
According to the above features, from a broad aspect, the present invention 
provides a contractable closure member for sealing an open-ended 
container. The closure members comprises a top wall and a bottom wall, the 
bottom wall being formed from an elastic material and having an integral 
continuous side wall. Seal means is formed with the side wall. The side 
wall is securable to the top wall with the bottom wall held in spaced 
relationship therewith. A retracting lever is pivotally secured to the top 
wall and has an engagement end and a pusher end. The pusher end is 
arcuately displaceable against a central portion of the bottom wall to 
distend the bottom wall whereby the side wall will be drawn inwardly to 
remove sealing pressure of the seal means when the closure member is 
positioned for sealing engagement in an open-ended container.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings, and more particularly to FIGS. 1 and 2, 
there is shown generally at 10, the contractable closure member positioned 
within the open top end 12 of an open-ended container 11. The closure 
member comprises a top wall 13, herein a rectangular top wall formed of a 
rigid thermoplastic material, such as polystyrene or polypropylene 
material. A bottom wall 14, FIG. 4, formed of an elastic material, such as 
low density polyethylene, and having an upwardly extending continuous side 
wall 15, formed therewith, is secured to the top wall 13 by a side wall 
15. The side wall 15 spaces the bottom wall 14 from the top wall 13, as 
shown. A continuous seal bead 16, which constitutes seal means, is formed 
integrally with the side wall 15 and engages the inner wall 12' in the 
open top end portion 12 of the container 11 when the closure member is 
positioned therein with the bottom wall 14 being in a normal position as 
shown in FIG. 1. 
A retracting lever 17 is pivotally secured to the top wall 13 in a manner 
which will be described in detail later, and defines an engagement end 18 
and a pusher end 19. As seen in FIG. 1, by pulling the engagement end 18 
of the lever 17 out of the plane of the top wall 13 (see phantom lines 
17') the pusher end 19 is arcuately displaceable against a central portion 
20 of the bottom wall 14 to distend the bottom wall whereby the side wall 
15 will be drawn inwardly to remove sealing pressure by the seal bead 16 
against the inner wall 12' in the open end portion 12 whereby to remove 
sealing engagement of the closure member 10 with the open-ended container. 
As shown in FIGS. 1 and 2, the open-ended container is preferably formed 
with an annular shoulder 21 whereby the closure member 10 will rest in the 
open top end portion 12 when the sealing pressure of the closure member is 
removed. 
Referring to FIGS. 1, 2 and 6, there is also shown a friction disc 22 
removably secured to the inner face 23 of the bottom wall 14 over the 
central portion 20 thereof. The disc 22 has a concave top face 24 to 
receive the free end 19' of the pusher end 19 of the lever 17 in 
frictional displacement thereover when the engagement end of the lever is 
displaced outwardly of the top wall whereby to apply pressure in the 
direction of arrow 25 to space the bottom wall 14 away from the top wall 
13 to distend the elastic bottom wall causing the side walls 15 to be 
retracted inwardly to remove sealing pressure as previously mentioned. The 
disc 22 is also formed of a rigid material such as polystyrene or 
polypropylene material and protects the bottom wall 14 from wear and 
further provides a better distribution of the pressure radially about the 
bottom wall 14. 
The disc 22 is provided with a bottom shoulder 26 whereby the disc may be 
retained in a snap fit within a disc retaining cavity 27 (see FIGS. 4a and 
4b) formed centrally in the inner top face 23 of the bottom wall 14. The 
disc retaining cavity 27 has a peripheral retaining ridge 28 to engage 
over the bottom shoulder 26 of the disc. 
Referring now to FIGS. 3, 3a and 3b, there is shown the construction of the 
top wall 13. The top wall has a substantially uniform top surface 30 with 
a cavity 31 formed therein to house the retracting lever whereby the lever 
rests substantially in or below the plane of the top surface 30. The 
cavity 31 defines a flat support portion 32 spaced inwardly and 
substantially parallel to the top wall 13. The cavity also defines a 
finger insertion portion 33 at an end of the cavity 31 spaced from the top 
wall center portion 34 to permit finger engagement of the engagement end 
18 of the lever 17, as is clearly shown in FIG. 1. The finger insertion 
portion 33 extends below the support portion 32 whereby the free end of 
the engagement end 18 of the lever extends over the portion 33 for ease of 
engagement of the lever. 
As also seen from the illustrated embodiment, the cavity 31 is 
substantially of a rectangular shape and defines two parallel side walls 
36 and an end side wall 37, located remotely from the central top portion 
34. An opening 35 or slot is formed in the cavity 31 and located generally 
along the top center portion 34. The cavity 35 is formed by a cut-out 
portion in the flat support bottom wall 32 immediately under the said top 
wall central portion 34 and the space created by not having an end side 
wall portion of the cavity 31 in this area. Thus, the parallel side walls 
36 form a free end portion 36' which extends across the opening at a 
respective end thereof. A pivot connection, herein a groove 38, is formed 
in the bottom edge 39 of the free end portion 36' of the side walls 36 
whereby to retain the lever 17 and permit arcuate displacement thereof, as 
will be described later. 
Referring now to FIGS. 1, 2, 5a and 5b, it can be seen that the lever 17 
extends within the opening 35 and is pivotally secured on an axis 
extending substantially along the opening 35 which is shown in FIG. 3 as 
being an elongate rectangular slot. This pivot axis is formed along an 
axis passing through opposed pivot pins 40 located on each side of the 
retracting lever 17 which is shown in FIG. 5a as being generally of 
rectangular configuration. These pivot pins have an eccentric transverse 
end flange 41 which prevents the lever 17 from pivoting outwardly of the 
top wall when the container is angulated or placed upside down. These 
shoulders fit in a respective one of the grooves 43 of flanges 42, as 
described below, and the eccentric prevents free rotation of the pivot 
pins. 
As shown in FIGS. 4a and 4b, the bottom wall 14 is further provided with a 
pair of upstanding flanges 42 extending from the inner top surface 23 of 
the bottom wall 14 and spaced on a respective side of the disc retaining 
cavity 27 and lie outwardly of the parallel side walls 36. Also, a recess 
or groove 43 is formed in the top edge 44 of each flange 42 with the 
grooves 43 lining up with respective flanges 41 of the pivot pins 40. As 
previously described, the flange 41 is of eccentric shape as well as the 
groove 43 and the upward pressure of the groove 43, due to its position 
relative to the top wall, cause the flange 41 to position itself in 
fitting engagement in the groove 43 to apply a closed biasing force on the 
lever to maintain the lever horizontally in a locked position. 
The pivot pins of the retracting lever 17 are captive in the grooves 38 of 
the side wall 36 and the end flange 41 in groove 43 of the flange 42 when 
the lever is positioned horizontally within the cover. As soon as the 
retracting lever is pulled out of the cover to remove the clamping 
pressure, the pusher end 19 of the lever pushes the bottom wall 14 away 
from the top wall 13 thereby separating the grooves 43 from the grooves 
38. However, in this position, a pressure exists along the plane of the 
lever maintaining the pivot pins 40 in the grooves 38. The retracting 
lever 17 is displaceable within an arc of approximately 90.degree. and is 
stopped at its vertical position, as shown in FIG. 3, by the oppositely 
disposed terminal edges 32' and 13' of the flat support portion 32 and top 
wall 13 respectively. Thus, when the lever is fully retracted, it is 
maintained in a substantially vertical position, as shown in FIG. 2. This 
is an indication to the user that the cover, although positioned within 
the open-ended container, is in non-sealing engagement with the container 
11. This is useful when it is not necessary to seal the container but to 
cover the open end and to permit easy removal of the cover such as when it 
is required to continuously insert foodstuff or other substance within the 
container. 
As shown in FIG. 5a, the free end 19' of the pusher end 19 is slightly 
curved to conform to the concave top face 24 of the disc 22 to provide 
smooth frictional engagement therewith. Further, as shown in FIGS. 2, 3a 
and 3b, an annular continuous depending wall 50 depends from the inner 
face 30' of the top wall 13 to solidify the top wall in the lever area and 
to support the bottom wall 14 to prevent distortion thereof and to keep it 
in a slightly stretched (prestressed) condition whereby as soon as the 
retracting lever 17 is actuated and the pusher end engages the disc 22, 
the bottom wall will start retracting the side walls 15. Otherwise, if the 
bottom wall was not pre-stretched, the initial displacement of the pusher 
end against the disc would cause stretching of the bottom wall 14 at its 
central area before any retracting force is applied on the side wall 15, 
its outermost area. Therefore, it would be necessary to make the lever 
pusher end lower and requiring more force by the user to obtain the same 
results. 
With reference to FIGS. 1, 3a and 4a, it can be seen that the top wall 13 
is captive at designated points along its outer periphery between wall 
support ribs 15' and the overlap flange 15", both formed with the side 
wall 15. The top wall 13 is provided with a circumferential flange 13" 
formed integral therewith and recessed downwards from the top surface of 
the top wall 13. The flange 13" lodges itself between the top edge of rib 
15' and the lower edge of the flange 15" to prevent the top wall 13 from 
collapsing in its circumferential area. 
When the closure member is a circular closure member, as soon as the bottom 
wall 14 is distended, the side walls retract substantially uniformly as 
the spacing between the center and the side wall is substantially 
constant. However, with rectangular or square containers, the side wall 15 
is not equidistantly spaced from the center. In order to maintain sealing 
pressure along the periphery of closure member 10 and to achieve 
substantially constant release of this pressure when the lever 17 is 
actuated, the seal bead 16 is slightly arced outwardly and thicker at the 
transverse central axis 52 and 53 of the rectangular closure, see FIG. 4. 
The thickness of the bead 16 gradually diminishes towards the corners 54 
of the cover. Thus, when the lever is retracted, more stretching of the 
bottom wall 14 will be required along the axes 52 and 53 before the bead 
in the corners 54 retracts whereby the bead will retract substantially at 
the same time throughout the circumference of the closure member. 
Furthermore, in order to improve uniform retracting displacement of the 
side wall 15 the bottom wall 14 may be molded with a non-uniform 
thickness. For example, as shown in FIG. 4, the material along the axis 
51, which is the longest point between the side wall 15 and the center of 
the closure member, would be thicker and decrease towards the axis 52 
which is the shortest point from the center to the side wall. Thus, the 
elasticity of the bottom wall would vary throughout the surface area 
thereof. 
Another means for causing substantially uniform withdrawing of the side 
wall, when the bottom wall is distended, is achievable by modifying the 
disc 22 whereby it has a contour which matches the contour of the side 
wall of the closure member. Thus, the disc being formed of a rigid 
material would extend substantially parallel and equidistantly spaced from 
the side wall 15 and distribute the downward pressure in a substantially 
uniformly spaced area on the bottom wall 14. Alternatively, the bottom 
wall 14 could be constructed with a thicker central base portion also 
contoured to be in equidistantly spaced parallel relationship with the 
side wall, much like the disc, except it would be molded integral with the 
bottom wall. 
It should be understood that an important feature of the present invention 
resides in the provision of a closure member having a distendable bottom 
wall which can retract a side wall which is not of circular contour. It is 
foreseen that a closure member of circular contour and having a straight 
edge portion in the contour could have the side wall thereof retracted 
substantially uniformly by the provision of a matching contoured disc or a 
thicker central portion or the provision of varying thicknesses in the 
bottom wall and extending radially to the portions furthermost from the 
central portion of the bottom wall. 
It is within the ambit of the present invention to cover any obvious 
modifications of the example of the preferred embodiment described 
hereinabove, provided such modifications fall within the scope of the 
broad claims appended hereto. For example, instead of the container having 
a shoulder 21, it may have a straight wall and the closure member could be 
provided an overlapping edge. Further, the lever 17 and its cavity could 
have different shapes provided they perform the same function.