U.S. patent number 3,595,449 [Application Number 04/865,915] was granted by the patent office on 1971-07-27 for dispensing container with follower discharge assistant.
This patent grant is currently assigned to Clevepak Corporation. Invention is credited to Roland C. Gardner, Paul W. Stump, Charles D. W. Thornton.
United States Patent |
3,595,449 |
Stump , et al. |
July 27, 1971 |
DISPENSING CONTAINER WITH FOLLOWER DISCHARGE ASSISTANT
Abstract
A plastic piston and tubular container for dispensing
semisolids, such as ice cream and the like. The piston has a flat,
flexible, obturating wall; a depending peripheral skirt or flange,
proportioned to guide the piston axially along the tubular
container, with a flared lower edge to provide a fluidtight seal;
and a central tubular hub, corrugated to provide radial
flexibility, for connecting either a rodlike or tubular push device
to the piston.
Inventors: |
Stump; Paul W. (North Olmsted,
OH), Thornton; Charles D. W. (Stamford, CT), Gardner;
Roland C. (Bay Village, OH) |
Assignee: |
Clevepak Corporation
(Cleveland, OH)
|
Family
ID: |
25346523 |
Appl.
No.: |
04/865,915 |
Filed: |
October 13, 1969 |
Current U.S.
Class: |
222/386 |
Current CPC
Class: |
B65D
83/0005 (20130101) |
Current International
Class: |
B65D
83/00 (20060101); B67d 005/42 () |
Field of
Search: |
;222/326,327,386,386.5,390,391,562 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Coleman; Samuel F.
Claims
What we claim is:
1. A molded plastic piston of unitary construction for use in
tubular dispensers comprising: a circular flexible obturating wall
with a flat outer or front surface deformable outwardly, i.e.,
forwardly, under force applied centrally thereof; a generally
cylindrical flange or skirt integral with the obturating wall at
the circumference thereof and extending away from the wall in only
a rearward direction from the top surface, and adapted to slide
within a tubular member and properly orient the obturating wall
therein, said flange or skirt abruptly increasing in outside
diameter at a location remote from the wall and terminating in a
circumferential portion the outside diameter of which is greater
than that of the obturating wall and major portion of the flange or
skirt to provide a sliding seal at the end of the flange or skirt
between the piston and a tubular dispenser; and a central hub
integral with and extending rearwardly from the obturating wall for
securing the end of a push member to the piston.
2. A piston as set forth in claim 1 wherein the piston is made of
high density polyethylene, and the diameter of the obturating wall
is on the order of 50 to 100 times as great as the average
thickness of the wall to provide sufficient flexibility so that the
wall will dome when pressure is applied at the hub during use.
3. A piston as set forth in claim 1 wherein the diameter of the
obturating wall is between 4 and 4.5 times as great as the axial
length of the skirt or flange.
4. A piston as set forth in claim 1, wherein said circumferential
portion is formed by an outward curve or flare of the flange or
skirt.
5. A piston as set forth in claim 4 wherein the outward curve or
flare of the skirt is small, being not more than 0.020 inch greater
in diameter than the obturating wall when the top surface of said
wall is in a flat condition.
6. A molded plastic piston of unitary construction for use in
tubular dispensers for ice cream or the like, comprising: a
circular flexible obturating wall with a flat outer or front
surface deformable outwardly, i.e., forwardly, under force applied
centrally thereof; a generally cylindrical flange or skirt integral
with the obturating wall at the circumference thereof, forming a
peripheral juncture therewith that has a rounded transverse
contour, extending away from the wall in only a rearward direction
from the top surface, and adapted to slide within a tubular member
and properly orient the obturating wall therein, said flange or
skirt abruptly increasing in outside diameter at a location remote
from the wall and terminating in a circumferential portion the
outside diameter of which is greater than that of the obturating
wall and major portion of the flange or skirt to provide a sliding
seal at the end of the flange or skirt between the piston and a
tubular dispenser; and a central hub integral with and extending
rearwardly from the obturating wall for securing the end of a push
member to the piston; said obturating wall having a central area
extending radially beyond said hub and terminating short of said
annular flange or skirt that is of greater thickness than the
remainder of said wall.
7. A piston of unitary construction for use in tubular dispensers
for ice cream or the like comprising: a circular flexible
obturating wall with a flat outer or front surface, deformable
outwardly, i.e., forwardly, under force applied centrally thereof,
to facilitate sliding of the piston within a tubular member; a
flange or skirt integral with and extending from the obturating
wall at the circumference thereof in a rearward direction and
having a major cylindrical portion adjacent the obturating wall
that, at a location remote from said wall, steeply or abruptly
increases in diameter to an enlarged circumferential portion, said
skirt being adapted to fit in slidable relationship within a
tubular member and properly orient the obturating wall therein, and
said enlarged circumferential portion being adapted to provide a
sliding seal between the flange or skirt and the piston and tubular
member; and a central hub extending rearwardly from the obturating
wall for securing the end of a push member to the piston.
8. In combination, a tubular container and a piston within said
container, said container having an open end with an inwardly
extending peripheral burr that reduces the size of said open end
with respect to the inside cross-sectional dimensions of the
container, and said piston having a circular flexible obturating
wall with a normally flat outer or front surface deformable
outwardly, i.e., forwardly, under force applied centrally thereof,
a central hub extending rearwardly from the obturating wall, and a
peripheral skirt or flange integral with and extending from the
obturating wall at the circumference thereof in a rearward
direction and having a major cylindrical portion adjacent the
obturating wall that, at a location remote from said wall, steeply
or abruptly increases in diameter to an enlarged circumferential
end portion, said skirt or flange being slidably received within
the container, and the circumferential end portion being more
readily movable past said burr in a direction of movement in which
the skirt or flange follows the obturating wall, as when the piston
is inserted obturating-wall-first into said open end, than in the
opposite direction, in which movement of the piston is
substantially obstructed by said burr to inhibit removal of the
piston from the container.
Description
This invention relates to dispenser containers, especially of the
type used to contain and dispense semisolid materials, and to an
improved piston therefor.
Semisolid materials, such as ice cream and the like, are marketed
in cylindrical paperboard tubes from which the material is
dispensed at one end by a piston or plunger moved from the other
end, typically by a stick. Such containers, when used to market ice
cream, usually hold a single serving, which is consumed directly
from the container as the piston is progressively advanced to expel
the product form the tube. Because of the relatively small quantity
and low cost of the product marketed in each container, the cost of
the container itself must be relatively low. Heretofore, a
paperboard disc with a central hole and metal eyelet has been used
as a piston and a wooden stick with a tapered end forced into the
metal eyelet has been used as a pusher to advance the paperboard
disc along the tubular container to expel the product. This
construction has not proved satisfactory in all respects.
One source of trouble in prior devices and a cause of production
losses during filling has been the tendency of paperboard discs to
move from an initial assembled position in the tube before the tube
is filled. In fact, at times the discs have fallen completely out
of the container tube during shipment or handling. Additional
problems have been caused by variations in stick diameter. The
stick diameter is somewhat critical if the stick is to be
effectively connected to the disc by a force fit into the metal
eyelet and if it is to effectively transmit force to advance the
disc. In use, excessive force must sometimes be applied to the
stick to dispense the contained material, e.g., if ice cream in a
dispenser is frozen quite hard. This can cause an undersized stick
to slide further through the eyelet instead of moving the disc.
Another problem is that while the product is being dispensed and
consumed a certain amount of melting occurs and the melted product
tends to flow past the paper disc and out the bottom of the
tube.
The present invention overcomes the above-mentioned and other
disadvantages of the prior art devices with a novel and improved
construction of a dispensing piston for containers of the type
described, which is inexpensive to manufacture and which
facilitates rapid and automatic assembly of the piston, push device
and tube.
A preferred piston embodying the present invention includes a wall
for obturating a tubular container, which obturating wall has a
smooth, preferably flat, top surface or face; a depending
peripheral skirt or flange extending rearwardly from the obturating
wall, proportioned to guide the piston axially within a container
tube so that it does not become skewed therein, and having an
outwardly flared lower edge that forms a fluidtight seal against
the tube wall and which retards sliding of the piston in the
reverse direction to that for dispensing; and a central hub
extending rearwardly from the obturating wall and surrounded by the
peripheral skirt, for receiving and frictionally retaining a stick
or tube used to push the piston for dispensing a product from the
container. The piston is typically inserted into an open-ended tube
and a push device is attached to the hub, by the container
manufacturer. So assembled, the container is shipped to a product
manufacturer who then fills the tubular container with the product
to be dispensed, such as ice cream or the like. By virtue of the
piston and tube construction, the tube, piston and push device are
readily maintained in assembled condition during such shipment to a
product manufacturer.
Advantageously, the piston is made from plastic, which provides
inherent flexibility and resiliency, and which retains its initial
dimensions and strength under varying conditions of humidity and
temperature, to which the piston is subjected during manufacture,
shipment, and use. In contrast, pistons of paperboard materials,
which expand or contract and change in strength with varying
conditions of humidity, can be troublesome to assemble and use and
often become disassembled during shipment. Materials that become
brittle when subjected to low temperatures, such as freezing
temperatures, are subject to breakage and do not perform as well as
a slightly flexible piston and are therefore also unsatisfactory.
Because of the flexibility of the obturating wall of the present
piston, pressure applied through the hub causes the obturating wall
to dome upward, relieving tension against the inside wall of the
tubular container about the obturating wall, so that the piston
readily slides within the container. The slight outward flare at
the lower edge of the piston skirt maintains an effective seal
against the inner wall of the tubular container during such
sliding. The flared skirt also serves to retain the piston within
the tube by not only resisting sliding movement in a reverse
direction to that in which the piston moves during dispensing, but
also by abutting an inwardly directed peripheral burr at either end
of the tubular container in the event the piston tends to move
beyond the ends of the container.
The central hub of the piston is tubular in construction, open at
the extending end, and axially corrugated. This construction, along
with the inherent qualities of the plastic material, provides a hub
that is flexible and resilient peripherally, so that it will expand
or contract to receive push devices of either the stick or tube
type, will accommodate variations in the diameter of such devices,
and will securely retain the push device in place with a friction
fit once the stick or tube is forced into or around the hub. The
central hub extends from the obturating wall a distance beyond the
peripheral skirt or flange and by so extending indicates the
orientation of the piston in automatic machinery used to assemble
the piston with a push device. Thus, the direction in which the
piston is facing can be readily determined by the presence of the
central hub.
Accordingly, an object of this invention is to provide an improved
piston for use with a dispensing container for semisolids, such as
ice cream and the like, which is inexpensive, retains its
dimensions under varying conditions, which is maintained in proper
relationship within a tubular container, which provides an
effective seal with the walls of a container while being readily
slidable therein, which accommodates stick-type or tube-type push
devices, and which facilitates automatic assembly of parts.
The above and other objects, features and advantages of this
invention will become more apparent from the following detailed
description, when considered in connection with the accompanying
drawings, in which:
FIG. 1 is a side elevational view, with parts in section, of a
dispenser embodying the present invention;
FIG. 2 is a side elevational view, with parts in section, similar
to FIG. 1, but illustrating the manner in which a piston of the
dispenser distorts when pressure is applied to dispense material
from the container;
FIG. 3 is a fragmentary sectional view of the dispenser of FIG. 1,
illustrating structural details of the piston and tube;
FIG. 4 is a perspective view of the piston of FIG. 1, illustrating
constructional details of the hub; and
FIG. 5 is a side elevational view of a piston embodying the present
invention, indicating certain dimensional features.
With reference to FIG. 1, a dispenser-container suitable for
packaging semisolids, such as ice cream, is indicated generally at
10. The dispenser 10 includes a cylindrical paperboard tube 12 for
containing semisolid material, a plastic piston 14 slidable within
the tube 12 for dispensing material from the tube, and a piston
actuator, i.e., a push device 16, such as a wooden stick or the
like secured to the piston and extending from one end of the tube,
for sliding the piston within the tube.
The paperboard tube 12 is preferably helically wound of a plurality
of plies, the inner ply of which is treated or is of a material
that is moisture resistant and suitable for containing a semisolid
material, such as ice cream or the like, intended to be packaged.
The tube 12 is typically manufactured by conventional techniques in
a continuous length, which is cut to suitable sizes. When the tube
is cut, an inwardly directed burr is formed at opposite ends. A
burr 20 at the lower end of the tube 12 is shown in FIG. 3.
The plastic piston 14 is preferably of one-piece or integral
construction, and is most suitably injection molded of high density
polyethylene, which is flexible, resilient, tough, retains its
dimensions and does not become brittle at relatively low
temperatures to which the dispenser may be subjected, as when it is
used to contain ice cream. The piston 14 includes an obturating
wall 22 corresponding in diameter to the inside diameter of the
paperboard tube 12 so that it fits tightly within the paperboard
tube. The obturating wall 22 has a normally flat or top surface 22a
and a lower surface 22b that is preferably stepped to provide a
circular central portion 22c that is thicker (e.g., twice as thick)
than the major surrounding portion of the wall to strengthen the
central area and provide a strong base for the piston actuator. On
the whole, the wall 22 is thin enough to be flexible so that it
will bow or bulge upwardly, as illustrated in FIG. 2, when axial
force is applied at a central location. This bulging of the wall 22
reduces the peripheral pressure between the wall 22 and the tube 12
so that the piston will more easily slide in the tube. It also
facilitates assembly of the piston and tube by making insertion of
the piston into the tube easier. Because the wall is normally flat,
dispensing pressure immediately bows it to a convex configuration,
at once reducing the peripheral frictional force on the piston.
When the piston is constructed of a material such as high density
polyethylene, the obturating wall 22 is sufficiently flexible to
permit adequate bulging when the diameter d (as indicated in FIG.
5) of the wall is on the order of 50 to 100 times the average
thickness t of the wall.
A peripheral skirt or flange 26 extends rearwardly from the
obturating wall 22 relative to the direction of dispensing movement
of the piston 14 in the cylindrical tube 12. The peripheral skirt
or flange 26 is continuous and essentially at right angles to the
obturating wall, providing a cylindrical guiding portion of the
piston 14, which slides in general contact with the inside surface
12a of the tube 12. The length of the skirt or flange is sufficient
to prevent skewing of the piston within the tube. For this purpose,
it has been found that the ratio of the diameter d of the
obturating wall 22 relative to the length L of the skirt or flange
26 should be between 4 and 4.5 to 1. A flange of shorter relative
dimensions does not adequately prevent skewing of the piston,
whereas a flange of longer dimensions is wasteful both of the
material of which the piston is made as well as of the length of
the cylindrical tube 12 needed to contain a given volume, since the
piston is totally contained within the tube and, as shown in FIG.
1, detracts from the volume available for the product. Also, in
general, the shorter the flange or skirt, the smaller is the
resistance to sliding of the piston within the tube.
Although the peripheral skirt or flange 26 is generally
cylindrical, it terminates in a slight outward curve or flare 28,
best shown in FIG. 3. This curved or flared terminal portion serves
as an effective seal between the inner surface 12a of the wall of
the cylinder paperboard tube 12 and the piston 14, especially when
pressure is applied to the piston 14 through the push device 16, as
will be described in more detail subsequently. In addition, the
flare 28 cooperates with the burr 20 at the lower end of the tube
12 to maintain the piston 22 within the tube once it is inserted.
As a result, any tendency of the piston to slide from the tube 12,
as during shipment or loading of the dispenser, is resisted. The
larger diameter and flexibility of the flared portion assures a
tight, sliding, seal between the piston and tube, which prevents
leakage past the piston and eliminates the need for a critical
piston fit within the tube. The flare or flange portion is of
sufficiently larger dimension than the diameter of the skirt or
obturating wall to cooperate with the burr 20 of the tube
notwithstanding variations in piston or tube diameter within
manufacturing tolerances. More specifically for optimum results,
the diameter f of the flared portion 28 (as shown in FIG. 5) at the
lower end of the peripheral skirt or flange 26 should be at least
0.005 inch greater and not more than 0.020 inch greater than the
diameter d of the obturating wall 22, when flat. By way of a
specific example, in a piston in which the diameter of the
obturating wall 22 and flange 26 is 1.630 inches, the diameter of
the curved or flared portion 28 is preferably 0.009 to 0.018 inch
greater.
A central hub 32 extends rearwardly from the obturating wall 22, in
the same direction as the flange 26. The hub 32 extends at a right
angle from the plane of the obturating wall 22 and is tubular in
shape, one end 32a being located at the back surface 22b of the
obturating wall, centrally of the thicker portion 22c, and the
other end 32b extending therefrom and being open. The thicker
portion 22c of the wall 22 inhibits tearing or breaking of the hub
from the wall 22 when nonaxial forces are applied through the push
device. As shown, the hub is of generally uniform cross section in
its axial direction, i.e., in radial planes, except for a slight
chamfer at the inside edge of the open end 32b. A push device such
as a rod or stick of the type indicated at 16 can be received
within the hub or a tubular push device (not shown) can be received
about the hub. The hub is sufficiently long to securely retain the
push device to the piston and to hold it at generally right angles
to the obturating wall 22. The tubular hub is shaped to flex, i.e.,
expand or contract, peripherally and is resilient so that it tends
to return to its original, formed, shape. Thus, the hub can be
stretched as by a rod or stick inserted into the hub, or can be
compressed, as by a tube that surrounds the hub, and due to its
resilience will frictionally retain the rod, stick or tube in
place. The hub will also accept minor variations in the diameter of
the rod, stick or tube due to this flexibility. The thickness of
the obturating wall 22 at the inner end 32a of the hub is
preferably equal to or slightly greater than that of surrounding
portion 22c, and hence is typically two to three times as thick as
the major portion of the wall 22, to withstand axial dispensing
pressures applied at that location by a sticklike push device.
In the preferred construction shown, the hub 32 is corrugated
axially to provide for peripheral expansion or contraction and also
extends from the inner surface 22b of the obturating wall 22 a
distance greater than that of the flange 26. While one particularly
suitable type of corrugation is shown in FIG. 4, in which rounded
axially extending depressed portions 33 extend radially inward
between axially extending convex portions 34 of somewhat greater
peripheral extent, other types of corrugations, pleats, or the like
are also contemplated which will provide for peripheral expansion
and contraction of the tubular hub. By extending a greater distance
than the flange, the hub serves to indicate the orientation of the
piston. That is, if the piston is placed against a flat surface,
resting on either its top surface 22a or on the lower edge of the
flange 26, it can be readily determined which side is facing or
contacting the flat surface by the disposition of the piston. The
piston will lie flat if resting on its outer surface 22a, but will
be somewhat askew if resting on the peripheral flange 26 and the
outer end 32b of the hub. This feature is utilized with automatic
machinery to be certain that the piston 14 is properly oriented in
the machinery that inserts or secures the push device 16 to the
piston 14.
It is most advantageous to form the piston 14 as a monolithic or
integral member entirely of plastic, by injection molding. However,
alternative constructions are contemplated. For example, the
obturating wall 22 and flange 26 can be molded of one piece and a
separate hub member can be attached. Such a hub member can be of
metal or plastic and can be extruded in a corrugated shape or can
be fabricated by deforming a cylindrical tube to form axial
corrugations and thereafter cutting the extruded or formed tube
into lengths corresponding to the length of the hub desired. Hubs
constructed in this manner are then welded or adhesively attached
to the inner surface 22b of the obturating wall 22 or, if provided
with a suitable groove or undercut, can be snapped into an aperture
that can be provided in the piston for this purpose.
Typically, the dispenser 10 is fabricated by a container
manufacturer and shipped in assembled condition to the manufacturer
of the material to be packaged. The container manufacturer will
form the piston 14, attach the push device 16 and assemble the
piston 14 within the tube 12. Because of the burr 20 on the end of
the tube 12 and the slight outward curve or flare at the base of
the skirt 26, the piston 14 is securely retained within the tube 12
once it is forced through an open end of the tube. This is true
even if dimensional tolerances have resulted in a relatively free
fit between the obturating wall 22 and the cylinder 12 or if the
cylinder has changed dimensions, due to changes in the environment,
especially changes in humidity. Thus, this construction overcomes a
serious disadvantage of known dispenser containers of this general
type in which the piston and push device often became separated
from the tubular container during shipment.
Once the container is filled with semisolid material, such as ice
cream or the like, the dispenser is ready for use. During use, the
semisolid material is dispensed through the upper end of the tube
12, in the orientation of FIG. 2, by moving the push device 16 and
piston 14 upward, in the direction of the arrow. Because the
obturating wall 22 is flexible, upward pressure exerted by the push
device 16 at the center of the obturating wall tends to bow the
wall convexly upward, as shown in FIG. 2. This, in turn, tends to
relieve the pressure between the piston and the tube 12 at the
periphery of the obturating wall, i.e., at the juncture of the
extending flange or skirt. Once the pressure is relieved, the
friction between the tube and piston is reduced and the piston
tends to slide relatively easily within the tube 12, facilitating
the dispensing of the material. At the same time, the outward curve
or flare 28 at the base of the skirt 26 maintains a liquidtight
seal between the inner surface 12a of the tube 12 and the piston.
As a result, even if the product is or has become very flowable,
there will be no appreciable leak-through past the piston 14.
From the preceding description of a preferred embodiment of this
invention, it will be apparent that the advantages and features
referred to have been achieved and a novel piston and tubular
container for dispensing semisolids has been provided. It should
also be understood, that while a preferred embodiment of this
invention has been described in detail, modifications or
alterations may be made therein within the scope and spirit of the
invention.
* * * * *