U.S. patent application number 11/820282 was filed with the patent office on 2008-02-07 for plastic injection mold assembly and method of molding threaded plastic parts.
Invention is credited to Alan A. Petrucci, William Sigsworth.
Application Number | 20080029935 11/820282 |
Document ID | / |
Family ID | 32907864 |
Filed Date | 2008-02-07 |
United States Patent
Application |
20080029935 |
Kind Code |
A1 |
Petrucci; Alan A. ; et
al. |
February 7, 2008 |
Plastic injection mold assembly and method of molding threaded
plastic parts
Abstract
A plastic injection mold assembly is disclosed in which an
electric servo motor very precisely controls rotational speeds and
amounts of torque applied to cores which extend into the mold
cavities as the cores are withdrawn from plastic components being
molded and simultaneously directs the linear distances which the
cores travel during such withdrawal. A method of accomplishing the
molding of plastic components in this manner is also disclosed.
Inventors: |
Petrucci; Alan A.; (Western
Springs, IL) ; Sigsworth; William; (Lisle,
IL) |
Correspondence
Address: |
GREGORY B. BEGGS;LAW OFFICES OF GREGORY B. BEGGS
5100 FAIRVIEW AVENUE
DOWNERS GROVE
IL
60515
US
|
Family ID: |
32907864 |
Appl. No.: |
11/820282 |
Filed: |
June 19, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10375745 |
Feb 28, 2003 |
|
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11820282 |
Jun 19, 2007 |
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Current U.S.
Class: |
264/328.16 |
Current CPC
Class: |
B29C 45/262 20130101;
B29C 45/73 20130101 |
Class at
Publication: |
264/328.16 |
International
Class: |
B29C 45/73 20060101
B29C045/73 |
Claims
1. A method of molding a component from a flowing plastic material
comprising the steps of providing a molding chamber in an injection
mold having a predetermined configuration of the outer form of the
component, providing a core member having a molding segment
adjacent one end of the core member disposed in the molding
chamber, filling the molding chamber around the molding segment of
the core member with the flowing molding material, cooling the
molding material in the molding chamber until the material is firm
enough to retain a shape matching the shape of the molding chamber
and the molding segment of the core, applying rotational power to
the core from an electric servo motor, simultaneously rotating and
longitudinally moving the core member until the molding segment
adjacent one end of the core member is separated from the
component, and ejecting the component from the molding chamber.
2. The method of claim 1 in which the rotational power applied to
the core is supplied from an electric servo motor programmed to
vary the speed and torque of the core member rotation.
Description
[0001] This application is a division of application Ser. No.
10/375,745 filed Feb. 28, 2003, the entire contents of which is
incorporated herein by reference.
[0002] This invention relates to plastic injection molds for
producing internally and externally threaded components. More
particularly, it relates to a mold assembly in which an electric
motor very precisely controls the various rotational speeds and
amounts of torque applied to cores which extend into the mold
cavities as they are withdrawn from the plastic components being
molded and simultaneously directs the linear distances which the
cores travel during such withdrawal. A method of accomplishing the
molding of plastic components in this manner is also disclosed.
BACKGROUND OF THE INVENTION
[0003] Heretofore, a variety of limitations have affected the
molding of threaded plastic components. When a hydraulically
powered rack was employed for extracting a metal core from a mold
cavity, the number of threads which could be made on the inside or
the outside of a component was limited because the number of
threads was restricted by the number of rotations required for
unscrewing the metal core from the component. The number of
rotations which a core could make was dependent upon the space
required around the mold to accommodate the length of the rack.
Moreover, hydraulically powered equipment had problems of fluid
spills and fluid leakage. Keeping an adequate supply of hydraulic
fluid on hand was a limitation as well. In addition, halting a
hydraulically driven rack's travel precisely was difficulot to
achieve, and the result was that substantial tolerances in the
finished components were required. Also, because substantial
mechanical movement was required for the rack, the speed of
ejecting finished components was restricted.
[0004] Electric motors have been used in molding machine
applications also. For example, U.S. Pat. No. 3,737,268, FIG. 12,
illustrates the use of an electric motor for driving a shaft
connected to a metal core with a threaded end inside a molded
plastic component in order to turn and loosen the core and free it.
In that patent, the core is moved rotationally by a belt-driven
motor. A pair of ejector rods, powered by a second motor timed to
cooperate with the first, are linearly moved to push the loosened
component off the core.
[0005] Another patent illustrating the use of a pair of electric
motors is U.S. Pat. No. 5,110,522. This patent relates particularly
to an injection molding machine in which two motors are required
for handling certain rectilinear and rotative drive requirements.
Similarly, two motors are required for the rectilinear and rotative
drives identified in U.S. Pat. Nos. 5,792,483 and 5,911,924.
[0006] U.S. Pat. No. 6,051,896 is an example of a patent which
discloses the use of servo controlled electric motors in a molding
machine. In that patent, one of the motors controls linear motion,
and a second motor controls rotary motion. U.S. Pat. No. 6,142,760
is generally similar, as is U.S. Pat. No. 6,267,580.
SUMMARY OF THE INVENTION
[0007] The present invention incorporates a servo motor to drive
one or more cores in an injection mold. In the new mold, the
motor's engagement to one or more threaded end cores turns the
cores at programmed speeds and at programmed torque to withdraw the
cores from the components which have been molded around or into
them. The motor continues to drive the cores in a programmed manner
rectilinearly backwards and away from the mold cavities and from
the components. Thereafter, as the mold is opened, the components
are ejected, usually by pushing them out of the mold. To repeat the
operation, the motor is reversed, and the threaded ends of the
cores are moved back into their original positions in the cavities
to be immersed again in or filled with plasticized molding
material, depending upon whether the components being molded are
internally or externally threaded.
[0008] Accordingly, in its first embodiment described below, this
invention is incorporated in a mold assembly for forming a
continuous internal thread inside a molded plastic element. A
recess in a plastic injection mold, defined by internal walls
inside the mold, forms the shape of the plastic article which one
desires to make in the molding process. An end cap for a pipe is an
example. A core is utilized which has a body portion with an
externally threaded segment extending into the recess defined by
the internal walls of the mold. The core also has a drive segment
on the body portion spaced apart from the threaded segment. A drive
member which has a drive portion complementary to and engaged upon
the drive segment on the core is connected to a programmable
electric motor. The motor is arranged to move the drive member
programmed distances at programmed speeds. When the motor is
activated, the drive portion on the drive member and the drive
segment on the core cooperatively move the core through sufficient
revolutions with any desired variations in speed to disengage the
threaded segment from the plastic article within the recess by the
end of the molding interval.
[0009] In an alternative embodiment, largely duplicative of the
first embodiment just described, the body portion of a core has a
segment having an aperture or pocket which is internally threaded
extending into the cavity defined by the internal walls of the
mold. A molded plastic component formed on such a segment of a core
has external threads arranged on the outside of the component.
[0010] From the foregoing, and from what follows, it will be
apparent that the present invention achieves numerous advantages
over the molding processes and equipment which preceded it.
[0011] It is an object of the present invention to provide a mold
assembly for producing internally or externally threaded plastic
components which have very exact tolerances with rapidly repeatable
precision.
[0012] It is also an object of the present invention to provide a
mold assembly for producing internally or externally threaded
components with threaded segments substantially longer than those
which were obtainable with rack-driven cores.
[0013] It is also an object of the present invention to provide a
mold assembly for producing an internally or externally threaded
component which controls the rotary distance traveled by a core
used in the molding process, the various speeds to be accomplished
by the core, and the linear distances to be traveled by the
core.
[0014] It is also an object of the present invention to provide a
mold assembly for producing an internally or externally threaded
component in which only one servo controlled electric motor is
needed for both rotational and linear movement of a core.
[0015] It is also an object of the present invention to provide a
mold assembly for simultaneously producing numerous internally or
externally threaded components during the same molding interval
utilizing several cores connected to the same servo controlled
electric motor.
[0016] It is also an object of the present invention to provide a
mold assembly for producing internally or externally threaded
components having very exact tolerances in substantial quantities
in a compact portion of the production space which is
available.
[0017] It is also an object of the present invention to provide a
mold assembly for producing internally or externally threaded
components which does not utilize hydraulic fluids.
[0018] Other objects and advantages of the invention will be
apparent to those skilled in the art of designing and using molds
for threaded plastic parts from an examination of the following
detailed description of preferred embodiments of the invention and
of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective view of part of a mold assembly
embodying the present invention showing an electrical control
component with its front cover panel partially open and cable
connections arranged to extend from the component to the mold, and
also showing a motor-carrying half of the mold with its inner face
exposed and turned upwardly;
[0020] FIG. 2 is a perspective view of an enlarged portion of the
mold assembly shown in FIG. 1 showing the control box door fully
open;
[0021] FIG. 3 is a perspective view of the motor-carrying mold half
shown in FIG. 1 and also including a perspective view of a second
mold half complementary to and aligned for mating engagement with
the motor-carrying half of the mold;
[0022] FIG. 4 is a perspective view of the motor-carrying half of
the mold shown in FIG. 1 rotated approximately 180 degrees in the
direction of arrow 4 in FIG. 1;
[0023] FIG. 5 is an elevational sectional view of the mold halves
shown in FIG. 3 in assembled, mating engagement taken in the
direction of and also along the line of arrows 5-5 shown in FIGS. 1
and 4;
[0024] FIG. 6 is an enlarged perspective view isolating some of the
elements of the motor-carrying mold half shown in FIG. 1;
[0025] FIG. 7 is a perspective view isolating some of the elements
of the motor-carrying mold half shown in FIG. 6;
[0026] FIG. 8 is a perspective view, partly broken away, of an
enlarged portion of some of the elements shown in FIG. 7 in
assembled relation with elements of the mold half shown in FIG.
1;
[0027] FIG. 9 is a perspective view, partly broken away, of an
enlarged portion of some of the elements of the motor-carrying mold
half shown in FIG. 7 taken in the direction of arrow 9 in FIG.
7;
[0028] FIG. 10 is a diagrammatic layout of the electrical control
component of the mold assembly shown in FIG. 1;
[0029] FIG. 10A is an enlarged portion of the electrical layout
shown in FIG. 10 taken along the line 10A-10A in FIG. 10;
[0030] FIG. 11 is an enlarged perspective view of an internally
threaded plastic component molded on the assembly shown in FIGS. 1
through 10;
[0031] FIG. 12 is an enlarged perspective view, partly broken away,
of the component shown in FIG. 11, taken along line 12-12 in FIG.
11;
[0032] FIG. 13 is a perspective view, partly broken away, of an
alternative form of the partially broken away element shown in FIG.
8; and
[0033] FIG. 14 is an enlarged perspective view of an externally
threaded component molded on the element shown in FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] The preferred embodiments of this invention shown in the
accompanying drawings will now be described, it being understood
that the preferred forms are illustrative and that the invention
described herein is embodied in the claims which are appended
hereto.
[0035] One embodiment of this invention is the mold assembly 10
which is particularly depicted in FIGS. 1 and 3. The assembly
includes a controls component 12 and a mold, one half of which is
the motor-carrying mold half 14, and the other half of which is the
complementary mold half 16 (See FIG. 3). The latter is configured
to sealingly engage the motor-carrying mold half 14 (See FIG. 5) in
order to form one or more cavities 18 and 18a inside the mold in
which plastic articles such as the fitting 20 (See FIGS. 11 and 12)
may be formed. In the embodiment of the mold assembly shown in
FIGS. 1 and 3, the outer configuration of a molded fitting, such as
the fitting 20 in FIGS. 11 and 12, depends upon the shape of the
cavity 18. The inner configuration, namely, the internally threaded
portion 22 of the fitting 20, depends upon the outwardly facing
threaded surface 46 of the end segment 24 (or 24a shown in FIG. 5)
of a cylindrically shaped metal core 26 around which the molten
plastic from which the fitting 20 is made is formed.
[0036] Alignment of the mold halves 14 and 16 as they are engaged
upon each other, in order to form the cavities 18 and 18a, is
achieved by lodging engagement rods 16A (on the mold half 16) in
sockets 14A in the motor-carrying mold half 14, as shown by arrows
17 in FIG. 3. Such alignment is assured further by engaging male
wedge member 15A in female wedge members 15B on the mold halves 14
and 16, respectively, accompanied by engagement of pins 16B on the
mold half 16 in sockets 14B in the motor-carrying mold half 14.
[0037] As shown in FIG. 1, the motor-carrying mold half 14 has two
motors, 28 and 30. Each motor is similarly arranged so that each
one is connected to and operates a set of four cores, as will
shortly be explained in detail. The motors 28 and 30 are connected
to their sets of cores in gear boxes 32 and 34, respectively. The
gear boxes 32 and 34 are mounted in mold frame members such as 36
and 38. The frame members are, in turn, mounted on support rails
such as are shown at 40 in FIG. 1, and those rails are attached to
a clamp plate such as is shown at 42 in FIG. 1. The clamp plate is
normally attached to a platen in a molding machine, neither one of
which is shown here since such molding machine configurations, and
how to operate them, are well known.
[0038] Injection molding machines are designed to hold various
molds, and also to open and close the mold halves. When the halves
are closed, molten plastic materials are injected into cavities
inside the molds so that the shape of the walls of the cavities, as
well as any other formative shapes inside the cavities, can be
transferred to the plastic material while it is in its liquid
state. After the molten plastic material has been cooled and has
frozen into the shape of the cavity walls and of the other shaping
forms inside the cavities, the molding machines open and separate
the mold halves so that the elements formed by the molten plastic
can be removed or ejected from the mold. Usually the mold halves
are arranged so that the separation plane between the halves is
substantially vertical. Then, when the halves are separated, the
plastic elements can easily drop into a bin below the mold when
they are ejected from the mold cavities.
[0039] Accordingly, with respect to FIG. 1, it will be understood
that a molding machine (not shown) operates a platen holding mold
half 14 and another platen holding mold half 16. The halves are
moved apart when a cycle of the molding process for creating
fittings 20 has been completed, and the fittings gathered from a
bin or other receptacle into which they have been ejected.
Thereafter, as further fittings are needed, the halves of the mold
are moved together, closing the cavities so that molten plastic may
be injected into them.
[0040] The cores 26 and 26a are identical. Each core has an end
segment 46 which extends into a molding cavity such as 18 or 18a
(See FIGS. 3,4, and 5). Inside each core a water-cooling tube 44
extends axially to carry cooling water into the end segments 46 of
the cores at appropriate intervals during the molding interval when
it is desired to cool the molten plastic which has flowed around
the segments 46. The tubes 44 are connected to unions 48 which
carry cooling water from hoses 50. Notably, the unions 48, while
stationary themselves, permit the tubes 44 connected to them in
junctions such as 51 adjacent motor 28 to rotate around their
longitudinal axes inside the cores so that the cores 26 which
contain them can be rotated too. Tubes 44a, unions 48a and
junctions 51a adjacent motor 30 (See FIGS. 4 and 5) are identically
constructed and perform the same way as tubes 44, unions 48 and
junctions 51, respectively.
[0041] Each of the motors 28 and 30 may be connected to a set of
four cores, such as illustrated in FIGS. 6,7,and 8, or to more or
less than that number, depending upon a variety of considerations
such as the size of the motor, the type of molding material which
is being used, and other molding parameters. As shown particularly
in FIG. 6, the motor 28 is connected to the four cores 26 inside a
gear box 32.
[0042] FIG. 7 shows the internal arrangement of gear box 32 and how
the cores 26 are connected to the motor 28. The drive shaft 52 of
the motor is connected to a worm gear shaft 54 that carries a worm
gear 56 for each core 26. On each core there is a worm wheel 58
forming part of a drive segment of core 26 which the worm gear 54
is engaged upon and drives. As detailed in FIG. 7, for example,
each worm wheel 58 is connected to the core 26 which it is engaged
upon by splines 60 arranged about the outside surfaces of the core
26. The splines are cooperatively engaged between and against the
walls 62 of an aperture 64 formed in the center of worm wheel 58.
The walls 62 forming the aperture 64 have land portions 66 and
groove portions 68 which correspond to and matingly engage the
outer configuration of the splines 60 and adjacent surfaces of core
26. When the worm gear is activated and driven by motor 28, worm
wheel 58 is rotated by the worm gear, thus moving the walls 62 of
the worm wheel and causing the core 26 to rotate. When there are a
number of worm gears and corresponding cores, the cores are rotated
in unison in response to the rotation of the worm gears by the
motor.
[0043] The splines 60 may be machined on one end of the generally
cylindrical steel body of a core 26 to form, along with the worm
wheel, a drive segment of the core body. Alternatively, the splines
60 may be made separately and fastened in place on the core body by
appropriately sized bolts or screws (not shown).
[0044] The radially outwardly facing surfaces 70 of the splines 60
are provided with threads 72 which are cooperatively engaged in
threads 74 disposed in a wall of the gear box in which the core 26
is mounted. In the embodiment illustrated (See FIGS. 8 and 9) the
threads 74 are arranged inside a ring 76 that is fastened with cap
screws 78 and a locking ring 80 into a socket 82 formed in a wall
of gear box 32. The ring 76 is situated adjacent the drive segment
of core 26 carrying the worm wheel 58. Splines 60 and the adjacent
surfaces of core 26 move slidably past the land portions 66 and
groove portions 68 of aperture 64 in the center of worm wheel 58
when the core 26 is rotated, driven by motor 28 and directed by the
cooperative engagement of threads 72 and 74. Accordingly, as the
core 26 is moved in a rotating manner by motor 28, and the segment
46 of the core 26 is moved for any rotational distance, core 26 is
simultaneously moved along the threads 72 and 74 by motor 28 in a
linear direction.
[0045] Motor 28 may be programmed to change from one rate of speed
to another during the linear and rotational movement of core 26,
and from one rate of torque to another, with corresponding changes
to the linear and rotational responses in core 26. Thus, when it is
desired to turn the core 26 with high torque and low speed, or
intermittently, as when loosening and unscrewing the core from
inside a hardened plastic article being molded (such as fitting
20), the motor may be directed by a program to operate in that
manner. After the core has been loosened from the inside of the
article, and it is desired to move the core 26 out of and away from
the plastic article more rapidly in a linear direction, the motor
28 can be programmed to adopt a new speed and torque. The change
may be made, if desired, without interrupting the continuous
rotation of the core. In this assembly, the movements of the core
are very precisely controlled, both linearly and rotationally, so
that core movements can be limited to specified thousandths of an
inch.
[0046] It will be apparent immediately to those skilled in the art
of designing mold assemblies of this general type that the distance
which a rack would have to travel, in a straight line pathway away
from the mold, in order to equal the rotational distance traveled
by a given point on the threads 72 and accomplish a specified
number of rotations of core 26 would require a lengthy open space
or vacant runway in a molder's plant. Such movement of a rack is
not practical, even if it were possible, when a substantial number
of threads are desired inside a molded plastic component which
would require a large number of core rotations in order to back out
of the component. In the present invention, using the motor-driven
threaded splines the core can be rotated many times without taking
up plant space, and consequently a longer threaded segment at the
end of the core can be employed, resulting in more threads and
longer threaded portions in the plastic articles being molded.
[0047] The over-all assembly 10 of the present invention is
substantially illustrated in FIGS. 1 and 2. The motor-carrying half
14 of the mold has also been described with particularity above. In
the embodiment referred to, the cores 26 include an externally
threaded end portion 24 for forming an internally threaded
component such as the component 20 shown in FIGS. 11 and 12. The
present invention is also adapted to produce an externally threaded
component such as the component 150 shown in FIG. 14.
[0048] A core 160 is illustrated in FIG. 13 for forming component
150. The core 160 is rotated and linearly moved in a manner and by
a physical arrangement identical to the manner and physical
arrangement for simultaneously moving core 26 rotationally and
linearly. However, the end portion of core 160 which extends into a
mold cavity such as cavities 18 and 18a is provided with a central
aperture 164 arranged longitudinally along axis 166 and extending
into the end portion 162 of core 160. The walls 168 of the aperture
164 are provided with a thread-forming helical groove 170 for
forming an external arrangement 172 of threads on the outside of
component 150. If an area without threads is desired, such as
segment 174 on the end of component 150 which might be used as a
cap on the finished component, a portion of the walls 168 (such as
the end portion 176) is not formed with a helical groove 170.
[0049] Turning now to a particular description of the assembly
controls which may be used with cores formed like core 26 or like
core 160, it may be noted that the motors 28 and 30 (See FIG. 1)
are connected by cables 84 to the controls component 12. Component
12 is powered from any convenient source (See FIG. 6, for example)
through cable 86. In the component 12 which is illustrated, a box
88 contains the electrical controls for the mold. A door 90 hinged
to the box 88 carries a variety of switches for the component 12.
The illustrated arrangement of the contents of box 88 may be
rearranged in any order or container. For example, control
component 12 could be integrated into the molding machine. However
it is collected and assembled, preferably it includes the following
elements.
[0050] There is a motor selector switch 92 which singles out which
motor on the mold is to be activated, or it may also be used to
designate which combination of motors to activate. The mold
illustrated here only includes the two motors 28 and 30, but it
will be recognized that further motors and the cores associated
with them in the manner described above may be used without
departing from the scope of this invention. Switch 94 is the on/off
switch to the motors.
[0051] Motors 28 and 30 are reversible motors. When one or the
other or both of them are driven in one direction to a maximum "in"
position, they position the threaded segment ends of the cores
which they respectively control, through the drive shaft, worm and
worm wheel rotation, in a maximum "in" position within the cores'
respective mold cavities. Similarly, when the selected motors are
driven in the opposite direction to a maximum "out" position, they
put the ends of the cores adjacent the splines 60, through drive
shaft, worm gear and worm wheel rotation in the opposite direction,
in a maximum withdrawal position from the cores' respective mold
cavities. A positioning switch 96 directs the selected motors to
locate their respective cores at any desired position between
maximum "in" and maximum "out." Switch 98 may be set to always
return the cores to a "home" position (usually maximum "in") so
that they begin each molding cycle at a preselected starting point
and produce a series of products, such as fitting 20, having very
uniform specifications.
[0052] A fourth switch, numbered 100 and located on door 90, is
provided to turn the selected motors on or off, and an indicator
light 102 is provided to let an operator know that the core
controls have or have not been activated. The master on/off switch
to the control component 12 is shown at 104. Cabinet door 90 is
usually latched or locked in a closed position by a lock or handle
106.
[0053] FIG. 2 illustrates the inside of the controls component 12.
Housed in the cabinet side of control box 88 are amplifiers 108 and
108a which contain program modules controlling the movements of the
cores. In particular, amplifier 108 controls motor 28, and
amplifier 108a controls motor 30. The program modules 109 (for
amplifier 108) and 109 (for amplifier 108a) hold and transmit the
programs for the motors, i.e., starting, stopping, changing speeds
at specified times and intervals, and similar motor movements
pursuant to programmed commands. These, in turn, control the
movements of the cores, including their disposition on or adjacent
to the components which are being molded. A terminal strip 110
distributes the electrical commands of the programs from the
program modules 109 and 109a and amplifiers 108 and 108a to signal
delay timers 114. The timers 114 are also connected to the molding
machine servicing the mold halves 14 and 16, and they regulate
signals from the amplifiers for the motors to stop, start or
otherwise move the cores according to programmed commands.
Electrical signals to the motors 28 and 30 are carried from the
control component 12 through motor cables 116 and 116a.
[0054] A diagrammatic layout of the contents of the control
component 12 is shown in FIGS. 10 and 10A. The motors 28 and 30 are
supplied from a 240 volt three phase line brought to the site and
into the box 88 through cable 86. In FIG. 10, the main power input,
which is fused, is shown at 118. From the main input 118, power is
supplied to the control functions 108 and 109, and their
counterparts, for motors 28 and 30, respectively, through fused
interconnects 120 (to motor 30) and 122 (to motor 28), through a 24
volt power supply 124, and through terminal strip 110. The
connections for motor 28 duplicate those for motor 30 and are not
shown in FIG. 10 simply for the purpose of avoiding visual
confusion. The terminal strip 110 is primarily an organizing
element to keep order among and to follow the conductors inside
control component 12. Such a strip may be as long as the unit shown
in FIGS. 10 and 10A, or longer or shorter, depending mainly upon
the number of motors utilized in the mold. The several inputs on
the terminal strip 110 to motor 28 are shown as switches in FIG.
10A numbered 1,2,3,4,5 and 6, and the inputs on the terminal strip
110 to motor 30 are shown as switches numbered 11, 12, 13, 14, 15
and 16. The power-on light for motor 28 is shown as L1 in FIG. 10A,
and the power-on light for motor 30 is shown in that Figure as L2.
A drive selector is shown as switch 45, and the switches connecting
the internal power supply to the molding machine are designated
+24. Power for the various control functions is supplied through
switches numbered 0 at the right end of terminal strip 110 in FIG.
10A. The motors 28 and 30 may be selectively operated to stop,
start, move to a "home" position, and may be operated to withdraw
the threaded molding segments of the core members at various speeds
partially or completely from their respective molding chambers
utilizing the channels of power connections established through the
terminal strip.
[0055] It is evident from the foregoing disclosure that even though
particular forms of the invention have been illustrated and
described, still, various modifications can be made without
departing from the true spirit and scope of the invention.
Accordingly, no limitations on the invention are intended by the
foregoing description of its preferred embodiments, and its scope
is covered by the following claims.
* * * * *