U.S. patent number RE31,086 [Application Number 06/048,429] was granted by the patent office on 1982-11-23 for plastic hinge construction.
This patent grant is currently assigned to W. R. Grace & Co., Cryovac Division. Invention is credited to Edward M. Johnson, Jr., John T. Stone.
United States Patent |
RE31,086 |
Johnson, Jr. , et
al. |
November 23, 1982 |
Plastic hinge construction
Abstract
In a blow molded container having a base and a lid, a hinge
formed of the molding material and defined in part by integral
journals depending from opposite sides of the lid and integral pins
extending from opposite sides of the base adapted to interfit with
the integral journals.
Inventors: |
Johnson, Jr.; Edward M.
(Matteson, IL), Stone; John T. (Saylorsburg, PA) |
Assignee: |
W. R. Grace & Co., Cryovac
Division (Duncan, SC)
|
Family
ID: |
26726115 |
Appl.
No.: |
06/048,429 |
Filed: |
June 14, 1979 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
721935 |
Sep 10, 1976 |
04029234 |
Jun 14, 1977 |
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Current U.S.
Class: |
220/840 |
Current CPC
Class: |
B65D
43/164 (20130101); B29C 49/482 (20130101) |
Current International
Class: |
B29C
49/48 (20060101); B65D 43/16 (20060101); B65D
051/04 () |
Field of
Search: |
;220/337,338,339,334
;264/DIG.33,299,343 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pollard; Steven M.
Attorney, Agent or Firm: Toney; John J. Lee, Jr.; William D.
Harps; Joseph P.
Claims
What is claimed is:
1. A plastic blow molded container blow molded from an extruded,
hollow parison of thermoplastic material and including a lid and a
base and being connected together for relative pivotal movement by
a hinge structure, with each of the lid and base having side walls,
said hinge structure comprising:
a pin structure molded integrally with one of the lid and base, and
a journal structure molded integrally with the other of the lid and
the base, said pin structure being rotatably supported by said
journal structure,
said pin structure comprising a generally solid pair of pin members
each having a generally circular cross-section and being formed by
the compression molding of the material generally from a double
wall of the parison to form said circular cross-section, said pin
members being axially aligned and extending axially outwardly from
opposite first side walls, each of said first side walls having a
first indented portion with the associated ones of said pins
extending outwardly from said first indented portion whereby said
one pin terminates proximately within the confines of said first
indented portion,
said journal structure comprising a pair of journal members
defining a pair of coaxially aligned openings for receiving said
pin members, each of said journal members depending from opposite
second side walls, each of said second side walls having a second
indented portion terminating in a generally non-indented strap
portion and having a support portion located axially inwardly from
said strap portion and from said second indented portion, said
strap portion defining a first generally semicircular opening and
said support portion defining a second generally semicircular
opening axially offset from and facing in a direction towards said
first generally semicircular opening whereby a pin opening is
defined by each of said journal members, each said pin opening
being in axial alignment with the other and being of a size to
rotatably supportingly receive one of said pins,
said journal members generally located within the confines of the
periphery of said second side walls,
said strap portion having a generally solid cross-section and being
formed by compression molding of the material generally from a
double wall of the parison to form said cross-section to have an
axial width greater than that of a single thickness of the
parison,
said first indented portion being of a depth sufficient to receive
the total width of the associated one of said journal members
whereby each of said journal members and said pins are located
within the periphery of said first and second side walls,
said support portion being of a solid construction and being formed
by compression molding of the material generally from a double wall
of the parison,
said strap portion being of a flexible construction whereby
assembly onto an associated one of said pins is facilitated and
each of said pins can be readily located in the associated one of
said pin openings.
2. The container of claim 1 with the blow molded container being of
a double wall construction and with said pin members each being of
approximately 0.250 inch diameter.
3. The container of claim 1 with the blow molded container being of
a double wall construction and with said strap portion having a
width of approximately 0.120 inch.
4. The container of claim 1 with the blow molded container being of
a double wall construction and with said strap portion having a
width of approximately 0.120 inch and with said pin members each
being of approximately 0.250 inch diameter.
5. A plastic blow molded container blow molded from an extruded,
hollow parison of thermoplastic material and including a lid and a
base and being connected together for relative pivotal movement by
a hinge structure, with each of the lid and base having side walls,
said hinge structure comprising:
a pin structure molded integrally with one of the lid and base, and
a journal structure molded integrally with the other of the lid and
the base, said pin structure being rotatably supported by said
journal structure,
said journal structure comprising a pair of journal members
defining a pair of coaxially aligned openings for receiving said
pin members, each of said journal members depending from opposite
first side walls, each of said first side walls having an indented
portion terminating in a generally non-indented strap portion and
having a support portion located axially inwardly from said strap
portion and from said indented portion, said strap portion defining
a first generally semicircular opening and said support portion
defining a second generally semicircular opening axially offset
from and facing in a direction towards said first generally
semicircular opening whereby a pin opening is defined by each of
said journal members, each said pin opening being in axial
alignment with the other and being of a size to rotatably
supportingly receive a pin member.
6. The container of claim 5 with said strap portion having a
generally solid cross-section and being formed by compression
molding of the material generally from a double wall of the parison
to form said cross-section to have an axial width greater than that
of a single thickness of parison,
said support portion being of a solid construction and being formed
by compression molding of the material generally from a double wall
of the parison,
said strap portion being of a flexible construction whereby
assembly onto a pin member is facilitated.
7. The container of claim 5 with said pin structure comprising a
generally solid pair of pin members each having a generally
circular cross-section and being formed by compression molding of
the material generally from a double wall of the parison to form
said circular cross-section, said pin members being aligned
coaxially and extending axially outwardly from opposite second side
walls,
said strap portion having a generally solid cross-section and being
formed by compression molding of the material generally from a
double wall of the parison to form said cross-section to have an
axial width greater than that of a single thickness of parison,
said support portion being of a solid construction and being formed
by compression molding of the material generally from a double wall
of the parison,
said strap portion being of a flexible construction whereby
assembly onto an associated one of said pins is facilitated and
each of said pins can be readily located in the associated one of
said pin openings.
8. A plastic blow molded container blow molded from an extruded,
hollow parison of thermoplastic material and including a lid and a
base and being connected together for relative pivotal movement by
a hinge structure, with each of the lid and base having side walls,
said hinge structure comprising:
a pin structure molded integrally with one of the lid and base, and
a journal structure molded integrally with the other of the lid and
the base, said pin structure being rotatably supported by said
journal structure,
said pin structure comprising a generally solid pair of pin members
each having a generally circular cross-section and being formed by
compression molding of the material generally from a double wall of
the parison to form said circular cross-section, said pin members
being axially aligned and extending axially outwardly from opposite
first side walls, each of said first side walls having a first
indented portion with the associated ones of said pins extending
outwardly from said first indented portion whereby said one pin
terminates proximately within the confines of said first indented
portion,
said journal structure comprising a pair of journal members
defining a pair of coaxially aligned openings .Iadd.each of said
journal members depending from opposite second side walls, each of
said second side walls having a second indented portion terminating
in a generally non-indented strap portion and having a support
portion located axially inwardly from said strap portion and from
said second indented portion, said strap portion defining a first
generally semicircular opening and said support portion defining a
second generally semicircular opening axially offset from and
facing in a direction to wards said first generally semicircular
opening whereby a pin opening is defined by each of said journal
members, each of said pin opening being in axial alignment with the
other and being of a size to rotatably supportingly receive one of
said pins,
said journal members generally located within the confines of the
periphery of said second side walls .Iaddend.for receiving said pin
members .Iadd.said journal structure having sufficient flexibility
to assist in assembling said pins into said aligned
openings.Iaddend.. .[.9. The container of claim 8 wherein said
journal structure comprising a pair of journal members defining a
pair of coaxially aligned openings for receiving said pin members,
each of said journal members depending from opposite second side
walls, each of said second side walls having a second indented
portion terminating in a generally non-indented strap portion and
having a support portion located axially inwardly from said strap
portion and from said second indented portion, said strap portion
defining a first generally semicircular opening and said support
portion defining a second generally semicircular opening axially
offset from and facing in a direction towards said first generally
semicircular opening whereby a pin opening is defined by each of
said journal members, each of said pin opening being in axial
alignment with the other and being of a size to rotatably
supportingly receive one of said pins,
said journal members generally located within the confines of the
periphery of said second side walls,
said strap portion having a generally solid cross-section and being
formed by compression molding of the material generally from a
double wall of the parison to form said cross-section to have an
axial width greater than that of a single thickness of the
parison,
said support portion being of a solid construction and being formed
by compression molding of the material generally from a double wall
of the parison,
said strap portion being of a flexible construction whereby
assembly onto an associated one of said pin is facilitated and each
of said pins can be readily located in the associated one of said
pin openings..].
Description
SUMMARY--BACKGROUND OF THE INVENTION
The present invention relates to hinge constructions for plastic
molded parts and more particularly to a molded plastic hinge
construction for a plastic, blow molded container having a base and
a lid connected by the hinge.
Various hinge constructions have been developed for plastic blow
molded containers having a lid and a base. One form is referred to
as a `live` hinge and is formed by simultaneously molding the lid
and base and having a relatively thin webb of material
interconnecting the lid and base. With a hinge of this type there
can be problems of fatigue and ultimate failure of the webb because
of the continuous flexing of the webb.
Another construction utilizes a more conventional type hinge and
has a metallic pin inserted through interfitting bosses after
molding. The problem with this latter type of construction is that
it requires an extra assembly step after molding and in addition
causes alignment problems. Further it is not uncommon for the pins
to be inserted out of alignment or with the lid and base out of
alignment resulting in a poor fit and an unsightly appearance. This
is important where the containers are used to house and display for
sale relatively expensive tools. An unsightly container could
possibly have a negative effect on the sale of the tools while a
well constructed container could have the opposite effect.
In the present invention the hinge is defined by a pin on one
member and a depending journal on the other. The members are blow
molded and generally are formed from an extruded parison of the
plastic material to have a double walled hollow construction with
each wall being relatively thin e.g. approximately 0.060 inch.
However, in order to provide adequate strength and rigidity the pin
and journal are formed by compression of a double thickness of the
extruded parison material and are not blown, and hence are solid
and not hollow. By molding the pin and journal integrally with
their associated members, accurate location of each with their
associated members can be provided and proper fit and alignment can
be more readily assured between the members. i.e. lid and base. At
the same time the members rotate relatively to each other and are
not faced with the fatigue problems of the `live hinge` which
continuously flexes.
In addition, in the present invention the journal is provided to be
at least partially of a strap like, depending structure and hence
defines a flexible structure which assists in assembly. Further the
opening in the journal is formed by a pair of offset semicircular
portions whereby forming is facilitated.
Also in the present invention the components of the hinge are
compression molded by plastically deforming the material of the
parison into a desired shape different from that generally defined
by the parison.
Therefore, it is an object of the present invention to provide an
improved molded plastic hinge for blow molded containers.
It is another object of the present invention to provide a plastic
hinge integrally molded with associated blow molded parts with the
hinge being non-blown and formed from compression of a double
thickness of the extruded parison.
It is another general object to provide an improved plastic
container and hinge of the above described type.
Other objects, features, and advantages of the present invention
will become apparent from the subsequent description and the
appended claims, taken in conjunction with the accompanying
drawing, in which:
FIG. 1 is a fragmentary perspective view of a lid and base with the
lid including integrally molded journals and the base including
integrally molded interfitting pins;
FIG. 2 is a partial schematic diagram depicting the molding of the
lid;
FIG. 3 is a fragmentary, partial sectional view depicting the
integral forming of the journal with the lid of FIG. 1 and
depicting a section of the lid generally taken along the line 3--3
in FIG. 1; and
FIG. 4 is a fragmentary, partial sectional view depicting the
integral forming of the pin with the base of FIG. 1 and depicting a
section of the base generally taken along the line 4--4 in FIG.
1.
Looking now to the drawings, FIG. 1 shows a container 10 having a
lid 12 and a base 14. The lid 12 has a pair of journals 16 (one
shown in phantom) which are depending from the lower portion of
opposite rearward sides of the lid 12. A pair of pins 18 (one shown
in phantom) extend outwardly from the upper portion of opposite
rearward sides of base 14 and are adapted to engage within the
journals 16 whereby the lid 12 can be pivotally connected to the
base 14 by the hinge defined by journals 16 and pins 18.
The lid 12 is a blow molded part, molded in a conventional manner
to have a double walled construction for its top 20 and side walls
22. In a similar manner base 14 has a double walled construction
for its bottom 24 and side walls 26. In both cases the double wall
is defined by a pair of inner and outer shells which are formed
upon inflation of the extruded plastic parison. The lid 12 and base
14 are blow molded of a thermoplastic material which is preferably
high density polyethelene.
Looking now to FIG. 2 an extrusion die 25 is depicted providing an
extruded, hollow parison 27 of a suitable thermoplastic material;
the parison 27 is acted upon in a mold assembly 29 to form the lid
12 and base 14. The blow molding process is well known in the art
and hence the details thereof have been omitted.
Looking now to FIG. 3, the lid 12 is molded in mold assembly 29 by
an outer mold 26 and a plug 28. The plug 28 interfits with the
outer mold 26 to pinch what would be the two opposite open ends of
the parison whereby a sealed plastic envelope is defined. Next the
envelope is inflated forcing it outwardly into engagement with the
confronting surfaces of the plug 28 and mold 26 to thereby
reproduce the shape of those surfaces. When this is done the
resulting walls are formed from a single thickness of the parison
material which will provide adequate strength for the lid 12.
However, it is desirable that the hinge components be made of
greater thickness to provide better wear, rigidity, strength, etc.
Thus in the present invention the journal 16 is not blown but is
formed to a desired shape by compression of a double thickness of
the material of the parison.
The journal 16 is defined by two axially offset generally
semicircular portions 30 and 32. The side wall 22 is partially
indented or slotted at 34 by a portion 36 of the outer mold 26. At
the same time a portion 38 of the plug 28 cooperates with the mold
26 to define the lower portion 30 in a generally semicircular
strap. The strap portion 30 is connected to the lid 12 by ribs 40
and 42. The other portion 32 is formed by a stepped portion 44 of
the plug 28 cooperating with the slot forming portion of the outer
mold 26. The portion 32 has a surface 45 semicircularly shaped by
plug portion 44 and with the strap portion 30 defines a
semicircularly offset, circular opening 46. Note that the parison
materials are compressed to form the strap portion 30 and the
complementary stepped portion 32. Since the parison materials are
compressed the subsequent inflation of the parison will generally
not affect the portions 30 and 32 which will thereby be maintained
as solid, not hollow, structures with a desired wall thickness and
desired wall shape. In the latter regard it should be noted that
the shape of the support surfaces of portions 30 and 32 can be
varied and need not be dictated solely by the parison wall
thickness. The double thickness of parison materials is utilized
mainly to provide a sufficient quantity of material such that the
desired shape can be attained upon compression. Hence the ultimate
thickness could be greater or less than double. In a preferred form
of the invention the width or thickness of strap portion 30 is at
least around 0.120 inch where the parison had a single wall
thickness of around 0.060 inch.
While the journal 16 is depending downwardly from the lid 12 it
does not protrude transversely outwardly beyond the general outer
periphery of the side walls 22 and hence does not needlessly
increase the overall size of the container 10.
In the process of molding, a thin wall 48 will result in the
opening 46. This wall can be knocked out either before assembly by
a conventional tool or will be removed by the pin 18 during
assembly. As will be seen except for this minor step the hinge is
completely formed as molded. Note that by forming the opening 46
with portions 30 and 32 axially offset the molding thereof is
facilitated.
The pin 18 is molded in a generally similar manner and is formed
from an outer mold 50 and a plug 52 of mold assembly 29. An
indentation 54 is formed on the outer shell of side wall 26 whereby
the pin 18 can be formed without extending substantially beyond the
periphery of the side walls 26 and hence does not needlessly
increase the overall size of the container 10. Note that the
indentation 54 is sufficient to receive the width of the depending
journal 16 whereby the pin 18 and journal 16 are located
substantially within the confines of side walls 22 and 26. One half
of the pin 18 is formed by the outer mold 50 and the other half
formed by the plug 52. The pin 18 is formed by compression of the
parison materials and hence will be essentially solid and will not
be expanded upon inflation of the enclosed envelope defined from
the parison.
In one form of the invention the pin 18 is formed with a retaining
bead 56 which is of a diameter slightly larger than the remainder
of the pin 18. The pin 18 is of a slightly smaller diameter than
opening 46 and can be journaled therein; the bead 56, however, is
slightly larger. The resilience of the materials permits adequate
elastic deformation to permit assembly. However, the bead 56 upon
assembly will maintain the parts from disassembly. In one form of
the invention the pin 18 had a diameter of approximately 0.250
inch.
The distance between journals 16 is the same as that between the
midpoints of the pins 18. When assembled the journal 16 will be
generally centered on pin 18. Thus for assembly the journals 16
must be deflected outwardly and/or the pins 18 must be deflected
inwardly to permit assembly. With the above noted construction the
flexibility of the depending strap portions 30 will assist in
assembly.
With the above structure, the journals 16 are molded integrally
with the lid 12 while pins 18 are similarly molded with the base
14. Thus axial alignment of the journals 16 and pins 18 can more
readily be provided whereby proper fits between lid 12 and base 14
can more readily be assured. In addition a hinge construction
having good wear and strength can be achieved. In this regard the
journals 16 and pins 18 rotate relatively to each other and
extensive flexing and fatigue is obviated. Note that with both the
journals 16 and pins 18 the resulting structure is formed by
compression molding a double thickness of the parison material; the
resultant shape, however, is not restricted to the parison shape or
contour. In other words, the double thickness of material is used
solely to provide a desired quantity of material, with that
material being plastically deformed into the desired shape.
While it will be apparent that the preferred embodiments of the
invention disclosed are well calculated to fulfill the objects
above stated, it will be appreciated that the invention is
susceptible to modification, variation and change without departing
from the proper scope of fair meaning of the invention.
* * * * *