Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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A MOT D FORMII`IG MAC~IINE FOR A FC)UNDRY
Field of the Invention
This invention relates to mold forming machines
and more particularly to an improved mold forming machine
having a vibratory impact apparatus in combination with a
ramming assembly for forming a mold about a pattern.
Background of the Inventlon
In a foundry, many dif erent methods and tech-
niques have been adopted in xecent years to modernize the
age old system of forming metal in a desired shape by
melting and casting the metal in a mold. Early forms of
such metal forming employed the use of a pattern in a
lower half or drag of a flask or mold box with sand and
clay tamped or packed around the appropriate portion of
the pattern until the sand and clay assumed the shape of
the appropriate portion of the pattern, whereupon the
pattern was removed. The same procedure was used to orm
the shape of the pattern in the upper half or cope of the
flask. Appropriate core pins were inserted when needed
and a gating system using sprues and risers were provided
whereupon the cope was assembled with and locked to the
drag and the metal was poured.
One type of mold forming machine available on
the market employs a pattern carrier for receiving a
plate upon which a portion of a pattern is mounted. The
pattern projects upwardly into a flask or mold box that
has been filled with loose foundry sand. The machine
provides for lining up the flask with a platen having a
plurality of downwardly projectinq squeeze or compressing
heads which advance into the flask for pressing the sand
around the pattern. The squeeze heads are withdrawn and
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the pattern carrier with the mold box is moved to the
ne~t station.
Another type of mold forming machine, called a
single station machine, has a cope and a drag pattern
shuttled in, squeezed and removed alternately on pattern
carriers. Another examp]e of a mold forming machine has
a cope and a drag pattern both mounted on the same carri-
er with a cope flask and/or a drag flask brought in
simultaneously or alternately whereupon the flask is
filled, squeezed and removed.
Although the above described mold forming
machines are but a few of the many available and although
they are efficient and generally acceptable, there are
certain patterns that have shapes and/or configurations
that do not fully accommodate to the squeeze or compress-
ing effect so that less than fully rammed flasks are
produced, resulting in rejected molds or, if the mold is
used, it results in less than an acceptable casting.
Different systems have been tried to overcome
this problem, such as blowing air up through the loose
sand to agitate the sand and distribute the sand prior to
ramming. Nonetheless, certain areas of the pattern are
sometimes bridged, producing less than acceptable rammed
flasks which must be rejected or which produce inferior
castings.
The present invention is directed to overcoming
one or more of the above problems.
Summary of the Invention
It is the principal object of the invention to
provide a new and improved mold forming machine having
improved compaction and flowability characteristics of
the sand in the making or producing of the molds.
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More specifically, i~ is an object of the invention to
provide such a machine wherein undesirable bridging in
flasks is avoided or minimized to an acceptable level to
eliminate rejected molds and/or inferior castings pro-
duced using such molds.
An exemplary embodiment of the inventionachieves the foregoing objests in a mold forming machine
having a base including means defining a mold making
station. Ram means are movably mounted on the base for
movement into the flask at the mold making station to ram
the contents of the flask. ~ vibratory impact apparatus
is directly beneath the pattern and is in contact with
the pattern carrier supporting the pattern and flask in
the mold making station. The vibratory action produced
by the vibratory means before and/or during the ram
operation causes the foundry sand in the flask to flow
more uniformly around the pattern and eliminates voids
therein and provides increased and uniform density to the
mold.
In a preferred embodiment of the invention, the
ram means and the vibratory means are disposed above and
below the mold making station. Preferably, the vibratory
means comprises an anvil located generally belo~ the
flask receiving station and mounted to engage the pattern
carrier received at that station. The vibratory means
includes a vibratory impact assembly consisting of a
motor, an unbalanced rotor, a spring assembly and a frame
operatively associated with the anvil.
Means may be provided to mount the unbalanced
rotor on the base through a spring system to the anvil.
In a highly preferred embodiment, the anvil
comprises a housing which contains a motor for driving
the unbalanced rotor through a spring assembly producing
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a linear motion that is so arranged with respect to the
anvil of the machine to produce or impart a vertical
motion to the pattern carrier thereby migrating the sand
and together witn the squeeze heads will compact the sand
about the pattern.
A rotating air vibrator or an electric vibrator
can be used to produce a high frequency but will not pro-
duce the required force. However, by using such high
frequency vibrators with a two mass system it is possible
to amplify the small force to produce the force necessary
to impart movement to the sand in the flask. Using a
high frequency of between about 720 cycles per minute to
3600 cycles per minute when amplified with a two mass
system will produce the force necessary to get migration
of the sand particles around the pattern.
Other objects and advantages will become
apparent from the following specification taken in
eonnection with the accompanying drawings.
Description of the Drawings
Fig. l is a side elevation of a mold forming
machine made according to the invention with parts broken
away and shown in section for clarity;
Fig. 2 is an end elevation of the machine taken
at right angles to the showing of Fig. l, also with parts
shown in section;
Fig. 3 is an enlarged, sectional view of a
vibratory mechanism employed in the machine;
Fig. 4 is a further enlarged view taken at
right angles to the view of Fig. 3 showing the vibratory
mechanism;
Fig. 5 is an end elevational view of a modified
form of vibratory mechanism;
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Fig. 6 is a side elevation view taken at right
angles to the showing of Fig. 5; and
Fig. 7 is a partial sectional view taken on the
line 7-7 of Fig. 6.
Best Mode for Carrying Out the Invention
An exemplary embodiment of a mold forming
machine ma~e according to the invention is illustrated in
the drawings and with reference to Figs. 1 and 2 is seen
to include a base or frame, generally designated 10. The
base 10 includes four vertical posts 12 disposed on the
corners of a rectangle and interconnected at their upper
ends by a rectangular configuration of two beams 14 and
two beams 16, only one of each being shown. The upper
ends of the posts 12 receive fasteners 18 to securely
fasten the beams 14 and 16 in place.
The lower ends of the posts 12 terminate in
feet 20 which in turn are seated and secured to an under-
lying surface 22 in the form of a floor or the like. A
first pair of spaced cross plates 24 extend between end
plates (not shown) secured to the feet 20 below the beams
16 at the lower end of the base 10 as do a second pair of
cross plates 26. In addition to the usual function of
strengthening the base 10, the plates 26 together with
four plates 28 (Fig. 1) which extend between and are
secured to the plates 26, serve as guide for p~rposes to
be described hereinafter.
As seen in Figs. 1 and 2, a pair of horizontal-
ly disposed, spaced box beams 30 extend through the base
10 at about the height of the upper ends of the cross
plates 24. Each of the box beams 30 journals a plurality
of flanged rollers 32 which serve as a conveyor for con-
veying an object to be processed by the machine into and
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out o the machine. ~ore specifically, that part of the
con~eyor defined by the beams 30 and rollers 32 within
the base lO defines a flask receiving stati.on, generally
designated 34. In one form of machine, a four sided
frame 36 is sized to ride on the rollers 32 and is
retained by the flanges thereon to removably mount a
pattern board 38 having a pattern 39 on at least the
upper surface thereon. A conventional flask 40 in turn
is placed on the pattern board 38 in any suitable fashion
and will either contain loose foundry sand before the
flask arrives at the flask receivinq station or will have
loose foundry sand added thereto at the flask receiving
station.
Above the flask receiving station 34, the base
lO mounts a so-called "squee7e head", generally designat-
ed 42, which may be of any known type. For example, one
suitabl.e construction is that embodied in the commercial-
ly available }lermanTI~oldmaster. The squeeze head 42
includes a plurality of fluid cylinders tnot sho~n) each
~o having an extendable rod 44 terminating in a respective
compactor head 46. As can be seen in Figs. 1 and 2, the
compactins heads 46 are arranged in close adjacency in
multiple rows and are movable between the solid line
position where they have entered the flask 40 and the
dotted line position where they are removed from the
flask 40. As is well known, the compacting heads 46 are
driven downwardly into the flask 40 when the flask is at
the flask receiving station 34 under the influ~nce of
fluid under pressure and serve to compact the foundry
sand about the pattern 39 carried by the pattcrn board
33. ~s alluded to previously, in the case of many pat-
terns, operation of the compacting heads 46 is sufficient
to produce satisfactory molds. However, as also alluded
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to previously, in the case of a number of patterns, par-
ticularly those of complex shape, the action of the com-
pacting heads 46 is insufficient to produce satisfactory
molds due to the tendency of the foundry sand not to fill
the voids and crevices in the pattern and due to the sand
bridging during compaction ~y the compacting heads 46.
To solve the problem, the invention contem-
plates that the machine be provided with vibratory means
mounted on the base 10 in proximity to the flask receiv-
ing station 34 and operable to vibrate the flask 40 and
its contents of foundry sand when the flask 4~ is in the
flask receiving station 3~ to flow or move the sand into
the crevices and voids and to break up any bridging prior
to and during operation of the compactor heads 46. As
seen in Fig. 1, two such vibratory means, each generally
designated 50, are disposed in the lower end of the base
lO between associated ones of the plates 28. As seen in
Fig. 2, such vibratory means 50 are also disposed between
the plates 26. Turning now to Fig. 3, one version of a
suitable vibratory means 50 includes an upper anvil or
hammer 52 and a vibration generating member 55. As best
seen in ~ig. 4, the upper surface 54 of each anvil 52 is
slightly crowned. When assembled into the remainder of
the apparatus as illustrated in Fig. 1, the upper surface
54 of each anvil 52 will be approximately in the plane of
the lower edge of the carrier frame 36. The crowning of
the surface 54 insures that as the carrier frame 36 is
being rolled on the rollers 32 into the flask receiving
station 34, edges of the frame 36 will not encounter
edges of the anvil 52 and prevent such movement. Such
edges of the frame 36 will gradually engage the crown
surface 54 of the anvil 52 as the frame 36 is advanced
into the station 34. Thus, the crown surface 54 prevents
any hangup of the frame 36 during such movement.
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Depending from each anvil 52 is one vibration
generating member 55 which includes side plates 56 as can
be best seen in Fig. ~. ~t the lower end of the side
plates 56 there is an interconnecting end plate 58 and
the anvil 52, the side plates 56 and end plate 58 define
a housing having an interior yenerally designated 50.
Within the housing interior 60, there is located a ver-
tically directed base plate 62 which mounts a motor 64,
preferably electric, having a rotary output in the form
of a shaft 66. While not shown, the shaft 66 e~tends
from both ends of the housing of the motor 64 and each
such end mounts an unbalanced rotor 68. As a conse-
quence, when the motor is energized, vibration will
result.
The upper end of the base plate 62 mounts a
horizontally directed plate 70, also within the interior
60 while a similar plate 72 is suitably secured to the
lower end of the base plate 62. Side plates 74 e~tend
between the plates 70 and 72 and are secured to the same
along with the plate 62. The vibratory motion produced
upon energization of the motor 64 will, of course, be
imparted to the plates 70 and 72 by reason of their con-
nection to the base plate 62 on which the motor 64 is
mounted. This motion is in turn conveyed to the anvil 52
via first spriny means in the form of spriny pairs 76 and
78. Specifically, the springs 76 are interposed between
the plate 70 and the undersurface of the anvil 52 while
the springs 78 are interposed between the plate 72 and
the upper surface of the end plate 58. As best seen in
Figs. 3 and 6, the sprinss of each pair may be separated
by a separator plate 80 mounted on the appropriate one of
the anvil 52 or the end platc 58.
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Returning to Figs. 1 and 2, cross plates 82
extend between and are secured to the lower ed~es of the
plates 26 and in turn mount a second spring means in the
form of a coil spring 84 which abuts the undersurface
of the end plate 58. The springs 84 act as isolation
springs for the vibrating means 50.
It will be recalled that the plates 26 and 28
act as guide means. Specifically, they act as guide
means for each of the anvils 52 and the asociated housing
defined by the plates 56 and 58. The same serve to guide
both the anvil and the motor 64 and unbalanced rotors 68
associated therewith in a vertical direction, thereby
limiting vibratory movement imparted to the anvil 54 pri-
marily to pure vertical motion.
The apparatus is completed by other structural
interconnecting plates and box beams in the locations
illustrated for strengthening purposes. And, of course,
circular locating disks such as that shown at 90 in Fig.
4 may be secured to various ones of the plates at the
points where the springs 76,78,84 abut the same to pro-
perly maintain the springs in the desired position. It
is to be understood that the vibratory means 50 could
operate without the springs 76,78 using only the isola-
tion springs 8~ and brute force from the vibrating means
to the frame, pattern board, pattern, sand and flask.
Foundry sand of the type used in mold forming
machines is generally wet such that particles of sand
will have shear angle forces therebetween which combine
with external static forces to create resistance to
relative movement between adjace~nt particles. It has
been found that operating the motor and unbalanced rotor
at high frequencies will produce a small force which is
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not suffic~nt to overcome the shear forces necessary tc
create migration of the sand particles. However, usin~
the high frequencies with a two-mass system will amplify
the small forces enough to reduce the shear forces be-
tween the particles so that the particles will move rela-
tive to each other and will work into the crevices of the
pattern. Using a vibratory means 50 of the general type
described above or as is shown in U.S. Patent No.
3,3~ ,815 to A. ~lusschoot, a range of high frequencies
fro~ about 720 cycles per minute to about 3600 cycles per
minute when combined with the two-mass system incorporat-
ing one mass, anvil 52, and a second mass, unbalanced
rotor 68, has been found to produce the unexpected move-
ment of the sand particles relative to each other such
that the sand particles move into apertures, crevices and
other surface irregularities on the pattern 39 to fill
same.
In operation, a carrier frame 36, pattern board
38 ar.d flask 40 with foundry sand in the latter is moved
along the rollers 32 into the flask receiving station 34.
During this operation, the compacting heads 46 are in the
dotted line position illustrated in Figs. 1 and 2. Once
the flask 40 is properly positioned in the station 34,
the vibrating means 50 is activated to operate in the
high frequency range between 720 and 3600 cycles per
minute. This vibratory motion is conveyed to the anvils
52 which are vibrated in the vertical direction due to
the guiding action provided by the plates 26 and 28. As
a consequence, the upper surface 54 of each of the anvils
52 will abut and vibrate the frame 36 which in turn will
convey such vibratory motion to the flask 40. Conse-
quently, the sand in the flask will be vibrated to cause
the sand particles to move and work into the voids and
crevices in the 2attern 39. ~he vibrating motion appiied
to the sand will cause any sand bridges to break up,
eliminating voids within ~he flask 40. At an appropriate
time either almost si~ultaneously with or shortly after
the vibrating means 50 has been activated, the squeeze
head 42 is operated to move the compactor heads 46 into
the flask 40 to exert a compacting force against the sand
to compress the sand into conforming relationship with
the shape of the pattern 39, The vibratory means 50 is
shut down once the compactor heads 46 have substantially
pressed the sand around the pattern. Continued action of
the compacting heads 46 will cause compaction of the sand
after the voids have been eliminated to assure that the
flasks are fully rammed. This in turn results in fully
acceptable flasks and high quality castings made using
such flasks.
Although the drawings in Figs. 1 and 2 show a
solid line position of the plural compactor heads 46 to
be substantially in a common plane, in practice the sand
will compact differently at different locations in the
flask partlally due to the presence of the pattern and
partially due to less dense sand accumulating in one
location as distinguished from another, The result will
be that each compactor head 46 is likely to end up at a
different level -- higher over the pattern, lower in the
corners. After the flask 40 and carrier 36 pass beyond
the receiving station 34, additional sand and binder mi.
are added to fill U,3 the flask. Appropriate sprues and
risers either are molded into the sand (for instance~ as
part of the pattern) or are cut into the sand in the
flask after compacting. The movement of the sand caused
by the high frequency vibrating means 50 into the voids
and crevices of the pattern and the brealcing up of
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bridges in the sand prior to or simultaneous with the
squeeze compaction of the sand creates an improved mold
upon completion of the squeeze compaction of the sand in
the flask.
A rotating air vibrator or an electric vibrator
may be substituted for the motor and unbalanced rotor
vibration generating system, the only limitation ~eing
that they are capable of operating in the high frequency
range between about 720 cpm and 3600 cpm.
A modified form of the invention is shown in
Figs. 5-7 wherein a vibratory means 150 inclu~es an anvil
152 which has two anvil surfaces 153,153 spaced apart
from each other IFig. 6) while having a common connecting
base 157, Appropriate guides 159 are provided to guide
the anvil 152 in a vertical direction both when under
vibration and when moved up or down as will be described
hereinafter. The anvil 152 is carried on a rigid plate
161 which extends beneath both anvil surfaces 153,153.
~lural sets of springs 163 are mounted between the rigid
plate 161 and an exciter plate 165, which e~citer 165 is
supported by isolation springs 167 mounted on platforms
169 on the floor. There are three sets of springs 163,
with one set aligning with one pair of isolation springs
167, a second set aligning with the other pair of isola-
tion springs 167 and the third set being mounted at the
midportion of the anvil 152, plate 161 and exciter 165.
A rigid mounting platform 171 is mounted to the floor and
supports a pair of inflatable air mounts 173 which air
mounts are connected to the underside of exciter 165.
The air mounts 173 are positioned with respect to the
center of the anvil in such a way that both spaced sur-
faces 153,153 of the anvil 152 are raised or lowered
simultaneously upon inflating or deflating the air mounts
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173. A source of air under pressure is used to inflate
the air mounts 173 which air mounts are of a convention-
al, commercially available type.
A pair of vibration generating members 155 are
S provided and include a motor 164 and a phir of unbalanced
rotors 168 driven by the motor. Each motor 164 iS SUP-
ported on a bracket 177 secured to the underside of the
exciter 165. The brackets 177 are symmetrically mounted
to the exciter 165 on opposite sides of the air mounts
173 such that the two vibration generating members 155
are mounted relative to the two surfaces of the anvil 152
so as to produce a uniform vibratory motion to both sur-
faces. The vibration generating members 155 are operated
by driving the motors 164 in opposite directions so that
lS pure vertical vibratory motion is provided to both sur-
faces of the anvil 152.
The vibration generating system is a two-mass
system with one mass being the anvil 152 and the other
mass being the unbalanced rotors 168. The two mass sys-
tem, when combined with the motors 164 and unbalancedrotors 168 operating at high frequencies in the range of
about 720 cpm to 3600 cpm will produce the unexpected
phenomenon in the wet sand in the flask whereby the sand
particles move and work relative to each other so as to
fill crevices and voids in the pattern.
In operation, a frame 36, a pattern carrier 38
with a pattern 39 and a flask 40 with wet sand therein is
moved into the flask receiving station. The anvil 152
and vibration generating members 155 are in the lowered
position with the air mounts 173 collapsed. The vibra-
tion generating members 155 may be started while the
anvil is in the lowered position or may be started after
the air mounts 173 are inflated to raise the anvil 152
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into contact with the frame 36. In either situation, the
anvil when in contact with the :Erame 36 provides a high
frequency vibratory motion to the flask which moves and
works the sand particles relative to each other so as to
fill voids and crevices in the pattern 39. At the appro-
priate time the squeeze head 42 is lowered and the corn-
pacting heads 46 are pressed against the sand to compact
the sand into pattern conforming configuration. The air
mounts 173 can be deflated with the vibratory members
operating and with the compacting heads 46 still compact-
ing the sand so as to release the anvil from the frame
and flask to prevent damage to the newly compacted mold
by the vibratory members continuing to vibrate the flask
after the compacting heads 46 have been removed from the
flask.
