Adjustable gasket alignment block

An assembly (10) for molding a two-tone, thin-walled plastic shell (12) for parts such as automobile door panels, control and instrument panels and the like includes a charge box (24) for supplying dry thermoplastic material to separate casting surfaces (30, 32) on a heated mold (22) selectively connected to the charge box (24) during the casting process. A pressurized inflatable seal gasket (60) is connected to the charge box (24) for sealing a division surface (36) on the heated mold (22) which surface (36) separates the casting surfaces (30, 32) of the mold (22). The seal gasket (60) is attached to the charge box (24) on a divider wall (42) via a sliding member (80) which positions the seal gasket (60) longitudinally along the divider wall (42). The sliding member (80) is secured to the divider wall (42) via threaded pins (86). The gasket seal (60) may be removed and reinserted in the slider member (80) providing automatic adjustment thereof.

TECHNICAL FIELD 
The invention relates to an apparatus for making thin plastic shells 
especially suitable for use in automobile trim components, such as 
interior door or instrument panels, and more particularly to two plastic 
shells having an integrally bonded connector joining the color section at 
a bond joint therebetween. 
BACKGROUND OF THE INVENTION 
The automotive industry has turned to the use of interior trim components, 
such as door panels, comprising a polyvinyl chloride shell. See, for 
example, the trim components disclosed in U.S. Pat. No. 3,123,403. The 
acceptance of such components has been because inter alia this type of 
construction permits a wide latitude in styling and color, and grain 
effects which are most desirable, particularly in the interior design of 
automobiles. 
The current state of the art includes a preformed grain vinyl shell made 
from dried thermoplastic powder particles which are applied to a heated 
shell mold from a powder box to form a continuous one-piece shell. 
In order to enhance the interior decor of an automobile, interior door 
panels and other parts have been prepared which include two separate 
plastic shell sections joined by a mechanical fastener. 
U.S. Pat. No. 4,562,025, issued Dec. 31, 1985, with a common assignee to 
this present invention, covers a mold method and apparatus for multi-color 
plastic shells which shell segments have their edges bonded at a 
particular break-line. 
U.S. Pat. No. 4,610,620, issued Sept. 9, 1986 discloses an apparatus for 
loading and releasing a recharge of two or more colors of thermoplastic 
color from separate compartments in a charge box for gravity flow into an 
mold configured to produce two shell segments and a separate overlapping 
color connector to bond the shell segments to form a one piece shell with 
two or more color tones to enhance the color of the interior of an 
automobile. An open-ended charge box is provided with a divider wall to 
form two separate compartments, each filled with a predetermined quantity 
of different powder. The mold has a division surface which cooperates with 
the divider wall to separate the powder content in each compartment of the 
charge box. The charge box releases the powder from the separate charge 
box compartments to flow evenly across the open end of the mold by 
gravity. A fixed gasket seals the division surface and the divider wall so 
as to produce separate two-tone segments on the heated surfaces of the 
mold. In theory, the seal gasket keeps the division surface clean for a 
subsequent application of the material thereagainst to form a connector 
that bonds the previously cast two-tone segments to form a single piece 
article with an integral joint between the two-tone segments. In practice, 
such a fixed gasket must conform to a division surface on each of a number 
of heated molds. The molds can be heated by suitable means such as hot air 
units of the type shown in U.S. Pat. No. 4,623,503 dated Nov. 18, 1986. 
Tolerance differences in the mold dimensions may leave margin gaps between 
the fixed gasket and the division surface. Powder from the charge box can 
seep into such gaps onto the division surface to create color smudges in 
the finish bond connector. 
A further assembly utilized by the assignee of the subject invention, 
includes an inflatable seal gasket which is operative to selectively 
bridge between the divider wall and the division surface when a charge box 
and heated mold are connected together. The inflatable seal includes a 
sealing bead thereon configured to completely cover the division surface 
to prevent seepage of the powder material from the casting surfaces to the 
division surface and to prevent resulting color smudges in a subsequently 
formed connector bond. The assembly solves the prior art problem of 
seepage onto the division surface due to geometric shape by inflating the 
gasket. However, a problem with this type of seal gasket is that the 
gasket is slideable along the divider wall and is allowed to slide 
therealong at any time proceeding and during the casting operation. The 
seal gasket may drift and slide out of longitudinal alignment with the 
division surface and divider wall over a period of time causing leakage or 
other failures of the gasket, and scrap of shells. 
SUMMARY OF THE INVENTION AND ADVANTAGES 
The invention is an assembly for molding a two-tone, thin-walled plastic 
shell in a heated open-ended mold from a charge of thermoplastic powder 
material in an open-ended charge box. The assembly includes a heated 
open-ended mold having a rib extending therefrom establishing two separate 
casting surfaces thereabout, a charge box adapted to be connected to the 
heated open-ended mold in open-ended relationship to form a closed system 
for casting the powder material and having a divider wall establishing two 
sources of the powder material. Also included is seal gasket means 
longitudinally slideable along the divider wall for selectively bridging 
between the divider wall and the rib when the heated open-ended mold and 
the charge box are connected in the closed system. The assembly is 
characterized by including retaining means selectively secured to said 
divider wall for receiving and maintaining the sealed gasket means at a 
predetermined position longitudinally along the divider wall. 
The advantages of the invention include that the seal gasket is not able to 
longitudinally slide out of position thereby preventing failures in the 
manufacturing of the thin-walled hollow shells and in destruction of the 
seal gasket or shells.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
An assembly 10 for molding a two-tone, thin-walled plastic shell 12 from a 
charge of thermoplastic powder material is generally illustrated in FIGS. 
1 and 2. 
The assembly 10 may process a variety of hollow shell parts. FIG. 6 
illustrates a typical automobile door panel application of a multi-color, 
single piece interior plastic shell 12. The assembly 10 is equally 
suitable for making other interior parts such as instrument panel covers 
and the like. The shell 12 is preferably made of polyvinyl chloride 
material and is backed by a layer of polyurethane foam 14 bonded to the 
shell 12 by a mold process such as in U.S. Pat. No. 3,123,403, issued Mar. 
3, 1964 for automobile armrest. An interior reinforcing insert 13 is 
connected at a joint 15 to an outer door panel 17 to form an interior 
space for a window lift mechanism (not illustrated) to raise and lower a 
window. 
The shell 12 is a plastic part with an integral lower panel 16 of a dry 
castable thermoplastic material of a first color and upper panel 18 of a 
dry castable thermoplastic material of a second color. The shell 12 
includes a bonded connector 20 of a selected color that overlaps the lower 
panel 16 and upper panel 18. The connector 20 is bonded to the lower panel 
16 and the upper panel 18. The upper panel 18 can include an arm rest 
segment 21 formed by a dry castable thermoplastic material having a second 
color contrasting or complementing the color of the lower panel 16 or 
other interior components. For example, the upper panel 18 can be red, 
blue, yellow or beige to contrast with or complement the interior color of 
the seats, headliners, crash pads and the like. The lower panel 16 can be 
colored a deeper complementary two-tone color of a character which has a 
low impact or scuff resistant qualities. The bonded connector 20 can be a 
color complimentary to the colors of the lower panel 16 and upper panel 18 
or the same as one or the other of the panels 16, 18. 
The assembly 10 includes a heated open-ended mold 22. A charge or powder 
box 24 is operated between raised and lowered positions with respect to 
the mold 22 by suitable handling equipment, exemplified by the type set 
forth in U.S. Pat. No. 4,664,867. The charge box 24 includes an open end 
26 which is configured to cover the planar extent of an opening 28 of the 
mold 22. Each of the molds 22 is coupled to the powder box 24 once the 
respective mold 22 has been heated to a casting temperature by suitable 
heating means. 
The heated mold 22 includes a pair of casting surfaces 30, 32 separated by 
a raised rib 34 therebetween. The rib 34 has a division surface 36 that 
extends between spaced side walls 38 of the mold 22. 
The rib 34 is located below the open edge of the surfaces 40 of the walls 
38 of the mold 22. In the illustrated example of the assembly 10, the 
upper edge surfaces 40 are shown in the same plane. It should be 
understood that these surfaces 40 may be of different levels depending 
upon the shape of the thin-walled shell 12 to be casted onto the heated 
mold 22. 
The charge box 24 includes a divider wall 42 which separates the charge box 
24 into first and second compartments 44, 46, each of which is configured 
to be filled with a charge of thermoplastic particles or powder material. 
FIG. 2 illustrates a fragmentary section of the charge box 24 on the mold 
22 to illustrate the relationship thereto during the casting process. The 
charge in the charge box 24 is a dry thermoplastic material which will 
melt and bond together when cast against the heated surfaces 30, 32 of the 
mold 22. In order to maintain separation between the material and each of 
the compartments 44, 46, the height of the divider wall 42 is greater than 
the maximum depth of either of the compartments 44, 46. The compartments 
44, 46 are filled from diagrammatically illustrated sources 47 of 
different colors of thermoplastic material. 
The charge box 24 further includes side wall gaskets 48. Each gasket 48 has 
a compression seal segment 50 with a base 52 slideably received for 
replacement in an extruded retainer 54 connected to the charge box 24 by 
suitable fasteners. The gaskets 48 seal the perimeter of the charge box 24 
to the perimeter of the heated mold 22 when they are clamped together at 
outwardly direction wall flanges 56 by clamps. 
The assembly 10 includes seal gasket means 60 longitudinally slideable 
along the divider wall 42 for selectively bridging between the divider 
wall 42 and the rib 34 when the mold 22 and charge box 24 are connected in 
the closed system. The seal gasket means 60 includes an inflatable seal on 
the divider wall 42 to seal the division surface 36 and to compensate for 
dimensional tolerance differences between different mold/powder box 22, 24 
combination to assure a positive seal against migration of different color 
materials from surface 30 to surface 32. 
Once the powder box 24 and mold 22 are clamped together, the side wall 
seals 48 prevent the escape of the powder material from the closed casting 
system which is rotated by drive means about an axis of rotation to 
distribute the layer of first and second colored particles of 
thermoplastic material on the surfaces. The seal 60 is inflated during 
such casting to prevent the flow of different colored particles between 
compartments 44, 46 and onto the division surface 36. 
The inflatable seal 60 is configured to accomplish several objectives. The 
inflatable seal 60 includes a base 62 connectable to the divider wall 42 
in fixed sealing engagement therewith to seal along the length thereof and 
to provide a structural base for operation between deflated and inflated 
positions. The divider wall 42 has a dove-tail groove 64 to receive the 
base 62 of the seal 60. 
The seal 60 also has a hollow core 66 with walls 68 which expand and 
contract when the core 66 is inflated. Such inflation occurs when the core 
66 is selectively connected to a source of pressure 69 by suitable valve 
control means 70. The seal 60 includes a sealing bead 72 which is held in 
pressure biased sealing relationship with the division surface 36 during 
the casting operation. 
The sealing bead 72 has a surface thereon which completely covers the 
division surface 36 when the seal 60 is inflated. Consequently, there are 
no edge gaps or seepage of the powder material from either of the 
compartments 44, 46 onto the surface 36 during the casting operation. 
When the seal 60 is in its deflated or retracted position, a gap remains 
between the sealing bead 72 and the division surface 36. In order to 
bridge the gap and compensate for dimensional tolerance difference in the 
height of the rib 34 on different molds 22, the hollow core 66 is 
pressurizeable to expand the walls 68. FIG. 4 shows the inflatable seal 60 
in its inflated or expanded position in which the sealing bead 72 is 
sealingly located on the division surface 36. 
The division surface 36 remains covered during the casting process. 
Consequently, the division surface 36 is clean when the mold 22 is 
separated from the power box 24. 
The assembly 10 includes retaining means 74 for receiving and positioning 
the seal 60 longitudinally along the divider wall 42 at a predetermined 
position and for connection to the divider wall 42 to maintain the seal 60 
at the predetermined position. The seal 60 includes attachment means 73 
for removably attaching the seal 60 to the retaining means 74 at the 
predetermined position. The attachment means 73 comprises a plug in the 
preferred embodiment. The retaining means 74 includes a sliding member 80 
slideable within a longitudinally extending groove 78 along the divider 
wall 42 and having a bore 82 therein for receiving the attachment plug 76 
for positioning the seal 60 in the predetermined position. The divider 
wall 42 includes a pair of oppositely disposed threaded apertures 84 
extending into the groove 78, and the retaining means 74 includes a pair 
of set screws 86 extending through a coacting with the threaded apertures 
84 for engaging the sliding member 80 to maintain the same in the 
predetermined position. The sliding member 80 includes longitudinally 
extending and opposing recesses 88 for receiving the pair of set screws 
86. 
In operation, the seal 60 is placed within the dove-tail groove 78 with the 
plug 76 placed within the bore 82 on the sliding member 80. The sliding 
member 80 is then positioned longitudinally along the divider wall 42 such 
that the seal 60 is positioned accurately, longitudinally along the charge 
box 24. The set screws 86 are screwed and tightened against the sliding 
member 80 within the recesses 88 to secure the sliding member 80 at the 
adjusted position 80 so that the seal 60 is at the predetermined position. 
The seal 60 will remain at the predetermined position as long as attached 
and secured to the sliding member 80. If the seal 60 is removed, 
reinsertion of the seal 60 will ensure proper positioning of the seal 60 
at the predetermined position. 
Following the casting operation, a thin layer of material is formed on each 
casting surface 30, 32 to form separate colored segments 16, 18 such as 
panels described above. A separate bonding layer of thermoplastic material 
is then applied to the surface 36 in a known manner by suitable means 
including paint or rolling a wet slurry of a suitable thermoplastic 
material or by dry casting the bonding thereon. A resultant in bonded 
connector 20 is then formed to bridge the gap between the color segments 
16, 18 and to bond the segments 16, 18 into one integral part with a 
precision styling line therebetween while the segments remain in the mold. 
The final product is removed from the mold as an integral unit. 
A typically powder casting process for a 2 color door panel includes the 
following sequence. 
1. preheat mold 22 tool. 
2. attach the powder box 24 to the mold 22 when it attains casting 
temperature to melt the thermoplastic material. 
3. rotate charge box 24 and mold 22 to form separate cast segments 16, 18 
of two-tone colors. 
4. dwell. 
5. unclamp. 
6. distribute connector bond material against clean, heated division 
surface. 
7. return the mold 22 to a cure oven (or it is heated by hot air by a air 
processing unit) to fuse connector end to two-tone segments. 
Further description of such a process is set forth in the aforementioned 
'620 patent. Suitable thermoplastic casting material include plasticized 
polyvinyl chlorides and related vinyl resins in dry powder form or in 
liquid slurry form for ease of gravity flow from the powder charge box 24 
during the cast steps. Typical examples of parts, plastic material and 
mold processes include the following: PVC resin, plasticizer, stabilizer, 
release agents and color pigments are combined in a high intensity mixer 
to produce a dry, flowable powder of each desired color. The process is 
known in the industry as dry-blending. 
The various components constituents may be selected as to type and ratio to 
provide the properties required both for the finished product and for easy 
of processing. Physical properties will not be too dissimilar from those 
obtained with liquid plastisol which is also used to manufacture similar 
products but has an inherent tendency to force objectional drips and runs 
when used to make complex shapes. 
Processing properties are such that when melting of the plastic powder 
occurs, densification results in exact reproduction of minute details such 
as grains, marks and stitches engraved or formed in the mold surface. 
Mold preheating temperature may range from 250.degree. F. to 450.degree. F. 
Since the thickness of the finished product is also governed by the time 
the powder is in contact of the mold, it should be understood that 
simultaneous charging of the powder to the mold can be a definite 
advantage. Also, if certain areas of the mold can be made to have a lower 
preheated temperature than others, it will permit molding a thinner shell 
in those areas, since temperature and mold-filled time determine the final 
thickness of the shell. Therefore, a very flexible range, for mold-filled 
time, of one second to ten seconds or more has been established. 
Depending on formulation, complete melting or fusion of the PVC powder can 
occur when mold temperatures read 350.degree. F. to 450.degree. F. After 
fusion, the mold is cooled to a temperature which will facilitate removal 
of the shell without damage. Specifically, the process and apparatus of 
the present invention provides even and complete distribution of 
thermoplastic powder material onto mold surfaces to form large, long, 
thin-walled, single piece two color or more shells with the pin stripe or 
common color connector bond to each shell segment for forming a unitary 
part for interior door panels or instrument panels and the like formed 
during short cycle mold cycles in limited plant floor space. 
The invention has been described in an illustrative manner, and it is to be 
understood that the terminology which has been used is intended to be in 
the nature of words of description rather than of limitation. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is, therefore, to be 
understood that within the scope of the appended claims wherein reference 
numerals are merely for convenience and are not to be in any way limiting, 
the invention may be practiced otherwise than as specifically described.