A molded container insert for providing a secure attaching point for hardware such as latches, hinges and handles. The insert includes a central portion having a rounded streamlined rear surface, a relatively large flat face and a pair of side wings spaced laterally from the central portion of the insert and which extend above the below the horizontal plane respectively defined by the top and bottom edges of the central portion.

FIELD OF THE PRESENT INVENTION 
The present invention relates to an insert member for use in forming 
rotationally molded plastic products, such as hollow cases, the insert 
providing an embedded securing device which can be used to attach items 
such as hinges, handles and latches to the molded product. 
BACKGROUND OF THE PRESENT INVENTION 
Many rotationally-molded plastic products, such as suitcase halves or two 
piece, hollow shipping containers, require use of latches, hinges and 
occasionally handles. These items must necessarily be attached to portions 
of the container adjacent the parting line of each half of the container 
and preferably within grooves or indented portions of the container side 
wall. If the container is to be water-tight and/or air-tight, not only 
initially but over a period of years, the latches and hinges must be 
attached in a way that will be strong enough to withstand shock forces up 
to the strength of the attached items and so that they resist a steady 
force equal to that portion of the compressive force on the container's 
gasket that each item bears, as well as repetitive intermediate forces due 
to vibration. 
Since attached items are subject to damage in service, it is also necessary 
to be able to replace them in the field with relatively simple equipment 
and without causing damage to the container. Fasteners can include such 
items as rivets, especially "blind" rivets, and screws with rivets being 
preferred as they are less likely to be removed by unauthorized persons 
trying to open the container during transportation and handling. 
In known arrangements where hardware is directly attached by rivets to the 
plastic wall of the container, the plastic, such as polyethylene, may not 
be hard or strong enough to hold the rivet and resist forces that may be 
applied. Consequently, various strengthening approaches have been tried, 
such as using a metal washer, in an effort to strengthen the inner joint 
between the rivet and the inner surface of the container so the rivet will 
not pull out. These approaches have not proved to be entirely successful. 
While rivets will normally be set tightly initially and will exhibit 
sufficient strength to hold a latch, for example, tightly against the 
container wall, and while there may be sufficient frictional force to help 
resist latch pull, such a connection will weaken in time due to rough 
handling during service in transportation where impact loads may have been 
applied to the latches and where there may have been alternate exposure to 
high and low temperatures. The impact loads will cause the rivets to 
loosen which, in turn, will change the latch connection. Also, it has been 
found that at somewhat elevated temperatures, the thermal expansion of the 
riveted plastic material immediately around the rivet and between the 
latch and the washer causes a thermal stress far beyond the compressive 
yield stress of polyethylene at the elevated temperature. Consequently, 
elevated temperatures cause permanent loosening of the rivets once the 
plastic returns to room temperature. 
A widely used commercially available, latch, is the Simmons Link-Lock No. 
2. When made of low carbon steel, this latch is rated at 350 lbs pull. It 
is capable of producing about 90 lbs. of gasket compressing force without 
undue pressure on the operator's fingers. This latch is normally attached 
with two 1/8 in. diameter rivets. If the plastic wall of the container is 
0.20 in. thick, the average compressive stress in the plastic due to a 90 
lb. steady load after the rivets are slightly loosened, is 
##EQU1## 
The actual peak stress in the plastic material is substantially higher 
because the rivet, once it is not axially tight, bears more heavily on the 
inner and outer surfaces of the container. A steady compressive stress of 
over 300 lb/in.sup.2 causes creep in polyethylene even at room 
temperature. At higher temperatures, the polyethylene is even less able to 
support the stress. Also, at higher temperatures, expansion of the 
polyethylene in the pull direction of the latch, causes a greater steady 
force to be exerted on the latch which in turn increases the stress in the 
material around the rivets. 
During container impacts, a latch rated at 350 lb. pull may exert forces up 
to this amount on the pair of 1/8 in. rivets. For a 300 lb. latch force, 
the average compressive stress around the rivet for 0.20 in. thick 
material would be: 
##EQU2## 
This value is far beyond the yield stress of polyethylene. 
During vibration in transportation, the container latches may be subjected 
to forces greater than the gasket force and less than impact forces. These 
intermediate forces may well be exerted thousands of times, and will 
gradually cause the rivets to become loose. 
When a rivet becomes loose, the likelihood of air and moisture leaking in 
is greatly increased. Some container manufacturers daub sealant over the 
inner ends of the rivets in an effort to prevent such leakage. 
If the rivets become sufficiently loose, the compression of the gasket 
material can be reduced and, thereby, permit leakage at the container 
parting line. 
In an effort to reduce the deficiencies of direct-riveting latches and 
hinges to polyethylene containers a rotomolded container using embedded 
rivet inserts or receptors was developed and is described in Barstow, Jr. 
U.S. Pat. No. 4,284,202. Here the embedded rivet insert receptors are one 
piece, elongated oval structures substantially like the one shown in FIGS. 
1-4. The substance of Barstow, Jr. is hereby incorporated by reference. 
The insert 10, is comprised of a body portion 12 formed with front and rear 
sections, 14 and 16, respectively, integrally connected together by a 
hinge 18. A pair of relatively long out-board wings 20 and 22 were used 
with each insert and extended from opposite sides of the front section 14. 
Each wing included spaced apart upper and lower horizontal arms, 24 and 26 
and an outer vertical arm 28 connecting the upper and lower arms together. 
As shown in FIGS. 1 and 4, just prior to use wings 20 and 22 would have to 
be bent at an angle from about 30 degrees to about 60 degrees toward the 
front section so as to conform to and generally follow the desired 
container shape where the insert was to be placed. Each insert was usually 
positioned in a well or recessed area, often called a groove, molded 
within the side wall of the container. Further, the insert was most 
desirably positioned adjacent or close to the parting line of each of the 
top and bottom sections of the container. 
The front wall of section 14 of the insert was also provided with apertures 
30, 32 through which blind rivets 34 could be inserted to fasten a latch 
or other item as indicated at 36. 
During molding the insert shown in FIGS. 1-4 was temporarily fastened to 
the interior surface of the mold by a magnet. The front wall, however, 
extended only slightly ahead of the wings, in an attempt to space the 
wings outwardly away from the interior of the mold in order to allow 
plastic to be formed there about and the front face was generally rounded 
except for a flattened area between apertures 30 and 32. It was also hoped 
that the insert would provide a greatly increased bearing area within the 
molded container material as compared with only using two 1/8 in. rivets 
directly in the plastic. When the rear section 16 was folded into place 
via hinge 18 it provided a hollow space 38, behind the front section, for 
the expansion of blind rivets. This space was made deep enough, 
front-to-back, to permit insertion of unpulled blind rivets, and with a 
volume sufficient to accommodate several drilled-off rivet ends to provide 
for re-riveting should that have to be done. 
The side wings or loops of the insert were designed to provide part of the 
bearing area and to resist the rotational forces exerted by the latches 
and hinges when closed. The wings were also designed to provide resistance 
to side-wise loads exerted by latches which might occur when the latch was 
open and hanging out from the container and struck from the side. 
It was found that the dimensions of the molds themselves varied from one 
mold to another so that in order to accommodate the shape of the indent or 
groove portion where this insert was to be placed, wings 20 and 22 had to 
be bent manually and in different amounts in order to accommodate the 
particular mold in which an insert was to be used. In many instances, 
wings 20 and 22, which were substantially long and about equal to the 
length of the main body portion, would be bent incorrectly either too far 
forward toward the mold or not bent far enough so that they would project 
too far toward the rea surface what would become the inside of the 
finished container. If the former occurred, the wings themselves would 
protrude through or be visible at the front surface of the container and 
by reducing the distance between the mold and the wings flow of the 
powdered plastic resin about the wings as well as the front of the insert 
was impaired. This caused the creation of voids at various places about 
the wings and about the main body portion, relative to the front face of 
the insert, which were objectionable. If the latter occurred, the wings 
could protrude through to the interior of the container and not be fully 
embedded. 
It was also found that in practice the wall thickness of the containers had 
to be 0.2 inches or greater to avoid having leaks due to molding voids 
about the inserts which communicated through the container wall. In many 
cases, the wall thickness of the container was greater than otherwise 
necessary due to the inserts. 
In order to minimize container weight and cost, it is desirable to have an 
improved insert which can be molded in a leak-proof manner in thinner 
container walls while retaining satisfactory attachment strength. 
SUMMARY OF THE PRESENT INVENTION 
The present invention relates to a modified insert that has an oval, 
rounded shape to provide a streamlined body over which the plastic resin 
powder can easily flow. Further, the insert includes outboard wings of a 
much different shape and which lie closer to the main body but extend 
vertically above and below a line extending parallel with the top and 
bottom of that main body. By forming the insert with this modified 
structure, dislogement during the molding cycle as well as rotation within 
the molded plastic are both substantially reduced and flow of the resin 
powder is not inhibited. Thus, the insert can be uniformly embedded so 
that it will resist substantial rotational loads and remain in place 
during molding. Since the wings are positioned much closer to the main 
body portion the insert can be moved closer to corners and due to the size 
of the opening defined within the wings, resin powder flows there through 
to and around the front areas of the insert to assure proper embedding. 
Other objects, features, and characteristics of the present invention, as 
well as the methods and operation and functions of the related elements of 
the structure, and to the combination of parts and economies of 
manufacture, will become apparent upon consideration of the following 
description and the appended claims with reference to the accompanying 
drawings, all of which form a part of this specification, wherein like 
reference numerals designate corresponding parts in the various figures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION 
With reference to the known insert set forth in FIGS. 1-4, the above 
background discussion describes this insert as well as the problems 
associated with its use. 
The present invention has been developed in an effort to resolve those 
problems and to find an insert that would resist rotation within the 
molded structure, about both a horizontal and vertical axis through the 
device. As requirements for the insert, it was determined that the insert 
must have a high resistance to pull forces, whether applied by a latch, 
hinge or handle, such that the wall into which it is molded will not be 
distorted by reason of that force. In addition the insert must have high 
resistance to lateral sheer forces without distorting either the insert or 
the wall in which it is molded. Molding must occur so that the insert will 
be fully encased and will not result in an air leak either through the 
creation of voids or because of its twisting within the molding material 
or and the shape of the insert must be stream-lined and sufficiently open 
so that the powdery plastic material within the rotating mold can flow 
around it freely and will form a complete and secure molded plastic layer 
about the desired portions of the insert, without the creation or 
development of any voids. 
Further, the vertical height of the insert must not be too great or 
excessive as it is occasionally desirable that a hinge or latch be 
positioned as close as possible to the parting line of the container 
portions. Thus, it is not appropriate for the insert to project above the 
parting line of the mold. Similarly, if the insert itself extends too far 
below the parting line of the mold then the handle attachment point will 
be also positioned too far from that parting line and that is equally 
undesirable. 
The preferred result is that the shape and design of the insert be 
substantially symmetrical about both the horizontal and vertical axis 
through the device, and relative to the points at which the items of 
attachment will be attached. This symmetry, will result in there only 
being one result as to how the shape of the insert lies within the mold 
regardless of how the device is placed in the mold thus eliminating the 
possibility that the installation of the insert could be done incorrectly. 
It was also desired to have the insert itself be as stable as possible 
when held magnetically against the mold wall to resist being tilted or 
otherwise moved or dislodged by the plastic powder resin that would pass 
over and flow around during molding. Because of the size of the insert 
shown in FIGS. 1-4 the wings provided a very large area and the flowing 
plastic resin powder frequently dislodged the insert from the desired 
position thereby resulting in a damaged molded product. 
Turning now to FIG. 5, the modified insert generally indicated at 100 is 
comprised of a main body section 102 which is integrally formed together 
with horizontally extending modified wings 104 and 106. The central 
portion of the structure includes an outer peripheral section indicated at 
108 and a relatively large, substantially planar front face 110 on an 
expanded or outwardly extending generally indicated at 112. The expanded 
portion 112 has a depth such that front face 110 is spaced about 0.110 
inches from the outer periphery 108 with this dimension being greater than 
the dimension for the similar portion in the insert shown in FIGS. 1-4 
which was 0.090 inches. 
Front face 110 is also provided with two apertures 114 and 116, as shown rn 
FIG. 9, which cooperate with two projections or nibs 118 for purposes of 
better aligning in insert 100 within the mold and provide the openings to 
use when riveting fixtures to the container. In order to temporarily 
restrain the insert 100 within a roto-mold, a magnet 122 is employed to 
provide the necessary holding force. The combined effect of magnet 122 and 
nibs 118 together with the insert streamlines and rounded shape of the 
insert causes the insert to be retained in a much more stable condition 
and be kept in the correct place within the mold so that it will not be 
tilted or otherwise dislodged by the plastic resin powder as the roto-mold 
is rotated. 
Each of the wings 104 and 106 are shaped substantially the same and each 
includes a vertically extending outer piece 130 and 132, respectively, 
which are connected at each end by connecting arms which extend at an 
acute angle back to the main body portion 102, with these connecting arms 
being indicated at 134-140. Arms 134-140 are positioned at approximately a 
45.degree. angle with respect to the axis of the outer vertical members 
130 and 132, respectively. The vertical members 130 and 132 are spaced 
from the peripheral area 108 by a distance of about 0.15 inches with the 
overall outer length of the insert 100 being about 1.65 inches and the 
central body having a length of about 1.15 inches. The vertical height of 
the wings at their widest point is about 0.9 inches with the vertical 
height of the body portion being about 0.65 inches so that the wings 
extend vertically through and beyond a horizontal plane defined by the top 
and bottom edges of the central portion of the insert. The distance 
between apertures 114 and 116, from center line to center line, is about 
0.55 inches and the thickness of the material forming members 130-140 is 
about 0.050 inches. 
The modified insert shown in FIGS. 5-9 also includes a rear member 150 
which includes four tabs 152, 154, 156 and 158 which when folded around 
the peripheral section 108 securely hold the rear member 150 in place. The 
front and rear members define a hollow space 160 therebetween as shown in 
FIGS. 8 and 9. Rear member 150 includes a pressed out area 162 that is 
characterized by rounded surfaces to enhance flow of resin powder about 
the insert. 
The rear member is made from material, preferably metal, having a thickness 
of about 0.015 inches whereas the front section 102 is made from material 
having a thickness of about 0.048 to 0.050 inches. 
As shown in FIG. 8, once the device is molded in plastic, with the plastic 
being generally indicated at 170. Arms 104 and 106 as well as the rear 
member 150 and a major portion of the front section including the beveled 
area 108 and excluding preferably only the front face 110 of the insert is 
fully imbedded within the plastic. In addition, rivets as indicated at 180 
and 182 can be used to hold a device which is indicated at 184 in place on 
the front of the device. As is noted from FIGS. 5 and 6, the rear surface 
of the insert has a very rounded rear face including the extended portion 
162 and its sides which curve gracefully down toward the marginal edges of 
the rear face that merge with the front section. In addition, arms 104 and 
106 can either be curved or can be bent at an angle and be otherwise 
straight with the intent being to generally follow the curve or direction 
of the wall of the mold to be used. Because they extend outwardly from the 
main body section a relatively short distance, in comparison with the 
embodiment shown in FIGS. 1-4, the exact shape is not as critical. 
Further, because the openings which extend therethrough are relatively 
large, resin powder can flow in a smooth stream line manner not only over 
the entire device but through such openings and about the in peripheral 
portions of front face 110. 
The design of the wings so as to extend above the top and bottom edges of 
the central portion of the insert, provides much better resistance to 
rotation and increases the pull out resistance even in relatively thin 
wall designs. Because of the reduced size and the increased pull out 
resistance which characterizes the present mold insert design, the 
indented areas within the containers can, when desired, be positioned 
closer to the corners thereby allowing a latch to be moved closer to the 
corner providing a greater amount of holding power closer to that corner. 
However, should the indent be too close to the corner or too thin, a drop 
of the container on a corner might cause the force applied to create a 
compression indent area which could spread or cause the container to 
break. 
In comparison pull tests between the original and new embodiments attention 
is directed to the following tables which sets forth the results of 
pull-testing inserts of both the old design and the new design. The wall 
thickness for the standard mold charge was about 0.20 inches; the wall 
thickness at an 80% mold charge was about 0.16 inches. 
______________________________________ 
INSERT PULL TEST 
Old Insert New Insert New insert 
Std. Charge Std. Charge 80% Charge 
______________________________________ 
1 750 lbs. 875 lbs. 750 lbs. 
2 725 800 750 
3 750 800 700 
4 800 825 750 
5 725 800 725 
6 750 800 750 
7 750 825 700 
8 800 825 800 
9 750 800 700 
10 725 800 750 
11 750 875 750 
Average = 
752 lbs. 820 lbs. 738 lbs. 
______________________________________ 
The oval shape of the present insert also provides a stream line body over 
which the plastic resin material can flow for that stream line flow causes 
less distortion or likelihood that the insert will move or be dislodged 
during holding procedures. 
Further, it should be noted that the plane established by the front face 
110 is spaced a farther distance from the peripheral rim 108 than is the 
distance between the front face of the insert shown in FIGS. 1-4 and the 
peripheral area thereabout. This serves to provide additional spacing 
between the wings 104 and 106 in the interior surface of the mold and 
helps assure the formation of solid plastic material between the wings and 
the inner portions of the insert in the inner surface of the mold thereby 
preventing the formation of voids in the plastic material. 
It should also be noted, that the outer periphery of the rear section 150 
does not extend above the marginal edges of the main center section of the 
front portion is clearly shown in FIG. 7 so that no portions extend 
outwardly beyond the periphery thereof. The flaps 152-158 serve only to 
hold the rear section onto the front section and are non-functional 
following molding. 
The loops must still be bent to conform to the indented container walls. 
But since the loops are much shorter than those of the original insert, 
the match between the bent loops and the mold is not critical to achieve 
coverage of the loops by the container material. Using the new insert, 
wall thickness reductions of about 40% have been made while retaining 
void-free air-tight moldings. The loops of the improved insert are 
considerably higher than the body of the insert. The loops terminate 
against the body of the insert at an angle of about 40 to 45 degrees from 
the horizontal. Pull tests of this insert with the force being applied 
parallel to the container wall as it would be the case for forces created 
by a latch in tension, show this insert to be more resistant to pullout. 
The original insert tended to fail by rotating about a horizontal axis at 
about 750 lbs. at room temperature with a polyethylene container wall 
thickness of approximately 0.20 in. The loops of the new insert are more 
effective in resisting rotation about both horizontal and vertical axes. 
Even with the wall thickness reduced to 0.16 in., and using the same 
polyethylene material, the new insert supported up to about 738 lbs. 
The sidewise strengths of both the old and new designs are equivalent. 
While the invention has been described in connection with what is presently 
considered to be the most practical and preferred embodiment, it is to be 
understood that the invention is not to be limited to the disclosed 
embodiment, but on the contrary, is intended to cover various 
modifications and equivalent arrangements included within the spirit and 
scope of the appended claims.