Note: Descriptions are shown in the official language in which they were submitted.
Background of the Invention
The present invention relates to the deflashing art
and more particularly to cryogenic deflashing apparatus
for the removal of flash in a low temperature environment
wherein the flash is embrittled for easy removal by the
bombardment of a high velocity pellet media stream.
As is well known, numerous articles of manufacture are
molded out of various elastomeric rubber or plastic
materials, as well as being cast from metallic substances.
By such molding and casting processes, there is often a
residual material or flash formed on the articles in the
area adjacent the interfacing mold surfaces, which is
functionally and aesthetically objectionable. Typically,
the practice heretofore utilized to remove such flash
was either hand trimming or abrasive tumbling.
Deflashing by hand is costly and oftentimes
difficult, requiring a substantial period of time and
labor to be expended to properly trim the particular
article. Furthermore, it is often difficult, if not
impossible, to accomplish a satisfactory result as where
part configuration prohibits manual access to the flash.
Similarly, altho~gh tumbling of articles in an abrasive
media has proven to be a useful alternative to hand
trimming, the tumbling process requires substantial
machine time, and is additionally substantially limited
by part configurations.
As a consequence, in recent years, it has been found
that highly satisfactory and economical deflashing may be
accomplished by subjecting articles to a high velocity
stream of deflashing media. Oftentimes, the media is
of steel, rubber, or plastic pelletized shot that is
thrown by an impeller or projected by a nozzle against the
-- 2
articles which are typically tumbled in a deflashing
apparatus.
In the case OL articles that are composed of
5 resilient elastomers or plastic materials, it has been
found advantageous to perform the deflashing operation
in a cryogenic environment utilizing a liquified gas (such
as nitrogen) that is implaced within the deflashing chamber.
Due to the relatively greater thickness of the article compared
10 to the flash, only the flash becomes brittle in a cryogenic
environment, whereby it may be readily removed
upon impact by the high velocity deflashing media
without marring the remainder of the article.
Much of the prior art deflashing apparatus has
15 utilized a throwing wheel or impeller whish is typically
r supplied media through axial ports and accelerates the
media along radially ex-tending vanes to direct a media
stream or pattern against the article. Although such
prior art impellers have proven useful in their general
20 application, there are substantial deficiencies associated
in their use.
In particular, prior art throwing wheels have proven
incapable of uniformly distributing the media over the
desired work surfaces within the deflashing chamber
25 with the majority of media stream being concentrated at
a particular area designated in the art as a "hot spot".
As will be recognized, such a hot spot prohibits the
uniform deflashing of single or multiple parts within
the chamber, as well as causing inconsistent wear on the
30 internal components of the deflashing apparatus.
To a limited extent, the prior art deflashing
apparatus has recognized this particular concentration
deficiency, with one Patent No. 2,049,466, issued
to Minich, disclosing a throwing wheel having impeller
35 blades of varigated length to vary the point of media
discharge from the impeller and provide a more uniform
discharge pattern. However, by such design, the speed
of the media projected is substantially reduced for the
shorter length vanes whereby the force of impact of the
4~3
media against the part is discontinuous and non-uniform.
Further, the prior art deflashing apparatus has
typically been fraught with serious transport problems of
the media from a storage reservoir or hopper io the
throwing wheel. These transport problems have resulted
in inconsistent quantities of media being supplied to the
throwing wheel and, in extreme cases, a complete
discontinuance of media flow due to clogging within the
transport system. With specific reference to cryogenic
deflashing apparatus, such transport deficiencies become
acute since discontinuance o the media pattern requires
the parts to be removed from the cryogenic glasting chamber
` to prevent the entire part from becoming brittle in
the super cooled environment. Further, such shut-downs
of the apparatus significantly deteriorate the overall
cost effectiveness of the device, and pose safety hazards
to personnel being exposed to the low temperature cryogenic
environment.
Additionally, the prior art apparatus has typically
incorporated a large housing, completely surrounding
the cryogenic deflashing chamber which is analogous to large
reefer or refrigerator with loading and unloading of
articles into the chambers requiring personnel to ente~
therein. Such manual entrance into the deflashing chamber
is extremely dangerous, posing significant safety hazards
to a personnel who may be subjected to cryogen gas
poisoning and extreme cold tem~eratures.
In this same regard, such large prior art apparatus
3~ typically admits large quantities of moistened atmospheric
air into the deflashing chamber during loading and unloading
of articles. This moistened air upon being colled
within the flashing chamber, forms ice upon the internal
components of the apparatus which deteriorates overall
machine operation and in severe cases causes machine
shut-down. Thus, there exists a substantial need in
the art for a deflashing apparatus which eliminates the
above-men-tioned operating and safety deficiencies.
Summarv of the Present Invention
.~ .
The present invention provides a deflashing apparatus
and more particularly a cryogenic deflashing apparatus
5 which substantially eliminates the deficiencies of the
prior art devices.
In particular, the present invention provides a
novel impeller or throwing wheel mechanism wherein a
control cage is axially positioned and rotatabl~ mounted
10 within the impeller to control the intake location of
media onto the impeller vanes. The angular orientation
of this control cage may be varied or oscillated during
machine operation to continuously shift the area of
media concentration across the deflashing chamber. As
15 such, a substantially uniform distribution of media across
t the deflashing chamber is provided which eliminates
inconsistencies in flash removal, as well as concentration
of wear on the internal components of the device.
Further, the present invention augments this uniform
20 distribution feature by an improved transport mechanism
; which delivers a consistant quantity of pellets to the
throwing wheel and éliminates the tendency of the media to
clog during transport from the hopper. These particular
transport improvements are made possible by a novel static
25 head, helical feed screw, and vacuum assisted transport
mechanism. In operation, the static head may be pre-set
to a desired level while the speed of the helical screw
and magnitude of vacuum assist may be adjusted during
machine operation. Thus, with the particular transport
30 and throwing wheel mechanisms of the present invention,
the density, intensity, and pattern of the media stream
may be varied to meet the specific requirements of a
particular article to be deflashed.
Further, the present invention overcomes the size
35 deficiencies of the prior art by providing a rather compact
deflashing apparatus which does not utilize a surrounding
refrigerator housing and facilitates the utilization of
conveyor handling tech~iques during the processing of
articles through the apparatus. As such, the present
~L~1~`4~3
invention eliminates the refrigeration units and
special handling equipment heretofore utilized in
the prior art.
Additionally, the prior art's temperature exposure
and icing deficiencies have been substantially eliminated
by the present invention's utilization of a sealed gas
lock door which prohibits interaction between the cryogen
environment and the atmosphere during loading and
I 10 unloading of articles into the deflashing chamber. In
¦ this same regard, the present invention facilitates
~ the automatic loading of articles into the deflashing
! chamber by a conveyor belt ~hich feeds the articles from
` an entrance enclosure into the cryogenic deflashing chamber
without directly or indirectly exposing operating personnel
to cryogenic environment.
In addition, once the articles or parts have been
placed within the deflashing chamber of the present
invention, they are continuously tumbled beneath the
deflashing media stream upon a belt maintained in proper
tension by a spring tension device which compensates for
the variable temperatures within the cryogenic environment.
Further, the entire apparatus incQrporates a plurality of
baffles, air locks, and openings that may be all
automatically operated. Thus, an automated device for
deflashing is provided which is significantly smaller,
safer, and more effective to use than the prior art
deflashing apparatus.
Description of the Drawings
These and other features of the present invention
will become more apparent upon reference to the dra~ings
wherein:
Figure 1 is a front elevational view of the deflashing
apparatus of the present invention;
Figure 2 is a fragmentary riyht side view thereof,
depicting the vestibule structure of the present invention;
4i~
Figure 3 is a left side view of Figure 1 showing the
vestibule interlock operating means which have been broken
away for illustration;
Figure 4 is a fragmentary view taken from the unseen
side or rear of Figure 1 showing the spent media transfer
feed mechanism;
Figure 5 is an elevational view of the spent media
transfer feed system of Figure 4 extending from the lower
to the top portion of the apparatus to provide a continuous
flow of media into the storage hopper;
Figure 6 is an enlarged cross-sectional view of the
transport mechanism and throwing wheel of the present
: invention;
Figure 7 illustrates an alternative embodiment of the
interlock system of the present invention;
i Figure 8 depicts a perspective view of an alternative
-; embodiment of the present invention, depicting the apparatus
with the interlock doors exposed;
~igure 9 is an enlarged cross-sectional view of the
throwing wheel and transport feed mechanism of the present
- invention taken along the lines 9-9 of Figure 8;
Figure 9a is an enlarged perspective view of the
media transport feed screw, control cage, and control cage
oscillation mechanism of the present invention;
Figure 9b is a schematic representation of the variable
media pattern produced by the oscillating control cage of
Figure 9;
Figure 10 is a fragmentary view of the throwing wheel
of the present invention taken about lines 10-10 of Figure
9;
Figure 11 is a cross-sectional view of the deflashing
apparatus of the present invention taken about lines 11-11
of Figure 8; and
Figure 12 is a perspective view of the media and
contaminan-t separation means of the present invention
interconnected with the entire deflashing apparatus.
48
Detailed Description of the Preferred Embodiment
Referring to Figures 1 through 6, a first embodiment
of the cryogenic deflashing apparatus of the present
invention is shown, being composed gener~lly of a housing
or casing C formed in a substantially rectangular
configuration. The housing C is preferably fabricated
from stainless steel having a double wall configuration
with the voids between the opposing walls being filled
with suitable insulation, such as a polyethylene foam
material (not shown). This particular insulated
stainless steel construction has been found to withstand
wear generated by the high velocity media stream, and
further prevent heat transfer from the cryogen environment
to the atmosphere.
The front wall of the housing or casing C has a door
,- D supported on hinges 10 which may be securely locked in a
closed position by a fastener 11 mounted to the periphery
of the casing C. A seal 12 (shown in Figure 2) is provided
between the opposing flanges 13 and 14 of the front wall 19
and the door D, respectively, to provide an air-tight
interface between the interior of the casing C (i.e.,
the deflashing chamber) and the door D~ The door D extends
transversely outward from the frontal wall 19 to form a
2S vestibule having an inlet or loading section 15 and an
outlet section 16 vertically oriented to one another
As best shown in Figure-2, the inlet and outlet loading
sections 15 and 16 are separated by a horizontal wall 17
which extends throughout the width of the door D and projects
fo~ardly from the distal end of the vestibule V to
reside within the vertical plane of the front wall 19 of
the casing C. As will be recognized by such a design,
both of the chambers 15 and 16 communicate with the
interior of the casing C (i.e., the deflashing chamber)
but are vertically isolatecl from one another. To permit
manual access into the chambers 15 and 16, while the door
D is maintained against the front wall 19, a pair of
::
cover plates 20 and 23 are mounted by way of hinges 21
and 24 to the outer walls of the vestibule V. Each of
the covers 20 and 23 preferably includes sealing means 25
and 26 (shown in Figure 2) as well as latch members 27 ana
28 (shown in Figure 1) to seal and maintain the covers in
their closed position. In this particular manner, the
vestibule V forms a relatively air-tight closure or outer
gas lock which effectively prohibits interaction between
the loading and the unloading chambers 15 and 16 and the
atmosphere.
At the areas of communication between the loading
and unloading chambers 15 and 16 with the deflashing chamber,
a pair of inner closure gates 29 and 33 are provided
which are pivotally mounted about horizontal axes 30 and
34, respectively. As shown in Figure 2, the upper closure
gate 29 extends ac~oss the opening into the loading chamber
15, and selectively engages a peripheral picture frame-like
seal 32 mounted on the distal ends of the upper wall 22
and partition 17 of the door D. Similarly, the lower
closure gate 33 extends across the opening from the
unloading chamber 16 to the deflashing chamber, and
sealingly engages a barrier wall 36. The barrier wall
36 is preferably formed as part of the vestibule V or
outer gas lock and extends angularly into both the
unloading chambers 16 and deflashing chamber.
As will be explained in more detail below, both of
these gates 29 and 33 are movable between a closed
position (as indicated by the solid lines in Figure 2) and
open position (as indicated by the phantom lines in
Figure 2) to allow selective communication between the
loading and unloading chambers 15 and 16 with the
deflashing chamber. Further, it will be recognized that
in the closed positions, the gates 29 and 33 effectively
isolate the vestibule V from the deflashing chamber and
form, in effect, an inner gas lock which prevents the
cryogen environment from interacting with the loading and
unloading chambers 15 and 16.
i4~
The loading chamber 15 is additionally provided
with a loading bin 37 which is pivotally mounted
adjacent one end about a horizontal pivot axis 38. The
bin 37 is preferably formed having radially-shaPed
sidewalls and an open upper end adapted to receive parts
(not shown) through the access cover 20. With the parts
loaded into the bin 37, the bin may be pivoted to a
position indicated by the phantom lines in Figure 2 to
10 insert or dump the parts into the deflashiny chamber.
Referring again to Figure 2, the detailed
construction of the deflashing chamber defined within
the interior of the casing C and its tumbler mechanism
may be described. As shown, an endless conveyor or belt
15 B extends in a generally L-shaped path through the
interior of the deflashing chamber having an
upper course adapted to tumble parts within
the chamber. In the preferred embodiment, the belt is
formed of spaced stainless steel segments to permit the
20 media to pass therethrough and is supported at both of its
sides by a pair of chain members 41 which are rigidly
attached thereto. These chain members 41 mate with a
pair of idler sprockets 48 and 49 on their lower
course and additionally extend vertically upward to
25 engage a driving sprocket assembly 43. The idler
sprockets 48 include a threaded adjustment member 47
which may be manually manipulated to adjust the tension
on the chain member 41.
The upper course of the belt B is guided
30 by a pair of large sprockets 52 (shown in phantom in
Figure 2) which are carried by a pair of circular
discs 53, each mounted to a common shaft 54 and
journaled to the sidewalls of the casing C. In this
manner, the upper surface or travel of the belt B is
35 maintained in a concave pocket-like configuration
which duriny movement of the belt B in the direction
indicated by the arrow in Figure 2, causes the parts
4~3
(not shown) disposed within the deflashing chamber
to tumble and be ro-tated thereon.
As best shown in Figure 1, the sprocket drive 43
is driven by a chain drive 56 which extends between an
external sprocket 57 mounted to the drive sprocket 43,
-- and a sprocket 58 mounted to the outward shaft 59 of a
gear box 60. The gear box 60 may be driven by a
conventional motor 61 and a timing belt arrangement 62
10 which engages the input pulley on the gear box 60. In
the preferred embodiment, the motor 61 may be of a
variable speed type or alternatively the gear box 60
can be utilized to establish the speeds with which the
belt B is driven. Thus, the tumbling action of the
15 parts (not shown) within the deflashing chamber, may be
adjusted to provide the most effective tumbling action
for a particular operation. Further, in the preferred
embodiment, the gear box 60 provides for reversible
rotation so that upon completion of the deflashing
20 operation, the belt B may travel in the direction
opposite the arrow shown in Figure 2, whereby the
articles (not shown) disposed upon the belt B may be
moved off the belt B through the gate 33 and into the
unloading chamber 16 of the vestibule V.
The deflashing chamber additionally includes
means for the admittance of a cryogenic gas or liquid,
which as previously mentioned, is utilized to embrittle
the flash on the articles placed within the apparatus.
As best shown in Figures 1 and 2, the means comprise
30 an input fitting 65 and piping 67 and 68 ~hich preferably
extend through the upper wall of the casing C to direct
the cryogen liquid stored in a reservoir (not shown)
downward through the deflashing chamber. To regulate
the amount of gas into the chamber, as well as the
35 temperature therein, a metering valve 66 is additionally
provided.
In Figure 6, the detailed construction of a first
4~
embodiment of the throwing wheel and media transport
mechanism of the present invention is shown. The
mechanism is composed generally of a throwing wheel
assembly 70, a helical feed screw 89, and a driving
assembly 71, which are all removably mounted to the
top wall of the casing C. As shown, the throwing wheel
assembly 70 is aligned with an opening 69 which
extends through the top wall of the casing C to form
the discharge throat of the apparatus.
The throwing wheel assembly 70 is composed of
- the throwing wheel or impeller 93, a housing 82, and a.
skirt or shroud which extends downwardly into the
discharge throat 69. The wheel 93 is formed
15 having a pair of opposed circular plates 94
with a plurality of symmetrically spaced fins or vanes
96 extending radially there-betweenr forming plural
radial slots 95. The plates 94 and vanes 96 are pre.ferably
maintained in position by fasteners 97 extending
through the vanes, and interconnecting the plates 94.
. The throwing wheel 93 is axially mounted to the
main drive shaft 76 of the drive assembly 71 by way of
a drive section 87 and coupling 85 which are respectively
attached to the wheel 93 by a plurality of fasteners 98
and keyed to the shaft 76. The shaft 76 is supported
by a bearing 77 and is journaled at its distal end 73.
A pulley 78 is mounted to the shaft 76 which receives
a belt 79, powered by a drive motor 80, as shown in
Figure 1.- The speed of the drive motor 80 may either
30 be variable via a conventional motor control (not
shown) or alternatively by a pulley adjuster 81 which
varies the space and thus the effective diameter of the
halves of the pulley 78. Thus, by way of the drive
shaft 7S, the throwing wheel 93 may be rotated at
35 variable speed to propel media (not sho~n) through the
: discharge throat 69 and into the deflashing chamber
A helical feed screw 89 is provided to transfer
(
the media tnot shown) axially into the throwing wheel
93. As shown, the shaft 88 of the feed screw 89 is
connected at one end to the drive shaft 76 and is
journaled at the other end in a bearing 92 supported
by an upstanding bracket 91. The feed screw 89 is
enclosed within a tubular member 90 which is preferably
formed o-E two aligned sections 90a and 90e. The section
90a includes an opening 90b which permits the
deflashing media to enter the tube 90 as from a hopper
116 ~shown in figures) and is maintained stationary by
a flange 90c and fastener 90d secured to the angle
bracket 91. The tube section 90e additionally includes
an opening 90f and is rotatably mounted for angular
movement about the shaft 88 of the helical feed screw
89 by a collar 90g. As will be explained in more
detail in relation to Figures 9, 9a and 9b, the
rotatable tube section 90e forms a control cage for the
intake of media to the throwing wheel 93 which may be
adjusted during operation either manually or automatically
to very the pattern of media discharged from the throwing
wheel 93.
In operation, media is supplied from the hopper
116 through the opening 90b in the tube section 90a to
fill the area surrounding the helical feed screw 89.
During this media supply, the feed screw 89 and
thro~ring wheel 93 are rotated by the drive shaft 76
such that the media (not shown) is transported by the
feed screw 89 laterally toward the throwing wheel 93.
An internal impeller section 99 rigidly attached to
one end of the shaft 88 of the helical screw ~9 causes
the media to travel upward into the throwing wheel 93,
wherein, due to the rotation of the throwing wheel 93,
the media is accelerated across the surface of the
vanes 96 and discharged through the clischarge throat
69 to bombard the articles within the deflashing chamber.
14
Subsequent to the impact of the media upon the
part, it is desirable to recirculate the spent media
back into the helical feed screw 8g and throwing wheel
93 assembly. To accomplish this result, the lQWer
portion of the deflashing chamber includes a V-shaped
hopper or trough 100 formed by a pair of walls 101
that ex-tend angularly downward from the sides of the
casing C. As shown in Figures 1 through 4, the trough
10 100 is provided with a transfer screw 103 adjacent its
- apex which is mounted on a shaft 104 supported by
bearings 105. The screw 103 extends through the rear
wall of the case C to communicate with an insulated
container 106. A motor or other means
15 107 may be utilized to rotate the shaf-t 104, causing
the media accumulating in the trough 100 to be
transported into the container 106.
The container 106 is preferably provided with a
screen 108 sized to separate or filter the media from
20 the flash particles freed during the deflashing process,
and is positioned in an overlying relationship with
the inlet 111 of a screw conveyor, designated
generally by the numeral 110. As best shown in Figures
4 and 5, the screw conveyor 110 is composed of an outer
25 flexible tube 113 which extends from the container 106
to the hopper 116 positioned above the top wall of the
casing C.
A helical screw 112 having a flexible shaft 114
is disposed within the tube 113 and is connected to a
30 motor 115. As will be recognized, by rotation of the
; motor 115 and flexible shaft 114, the helical screw
112 transports the media entering through the opening
111 through the tube 113 and discharges the media into
the hopper 116 for entry into the transport and
35 throwing wheel mechanism 93. Further, to facilitate
4~
the addition of supplemental media into the system, a
top closure 106a is provided upon the container 106.
With the structure defined, the operation of the
deflashing apparatus of Figures 1 through 6 of the
present invention may be described. It will be
recognized that initially the deflashing chamber is
lowered to operating temperatures by the introduction
of cryogen gas through the piping arrangement 67 and
10 68. At operating temperature, the particles or parts
to be deflashed, are placed within a loading bin 37
of the vestibule V by opening the cover plate 20.
During loading, both of the inner gates 29 and 33 of
~the vestibule V are in their closed position to prevent
-15 the transfer or interact;on of '_he cryogenic gas containea
within the deflashing chamber with the atmosphere.
Subsequently, the cover 20 is closed, sealing off
;,the atmosphere from the vestibule V and the inner gate
29 may be released (as by removing a pin 120 shown in
20 Figure 3, or releasing a holding means such as a
crank arm 121) to move to the phantom line position,
shown in Figure 2. In this position, the bin 37
~ containing the articles to be deflashed (not shown) may
`~ be pivoted about its axis 38 to a position indicated by
~ 25 the phantom lines in Figure 2, wherein the articles
- are dumped onto the conveyor belt B. Subsequently,
the bin 37 and gate 29 may be returned to their initial
position, thereby again sealing the vestibule V from
the deflashing chamber.
The conveyor belt B travelling in a direction
indicated by the arrows in Figure 2, tumbles the
articles on its upper concave course with any
articles accidentally moving out of the concavity being
urged back thereon by the angularly inclined walls 29a
35 and 29b of the upper gate 29 By timing the period
that the articles are maintained within the deflashing
16
chamber, the flash of the articles ~Jill become embrittled
in comparison with the remainder or main body of the
articles so that the media being discharged through
S the deflashing chamber by the throwing wheel 93,
effectively removes the flash from the articles without
marring the remainder of the articles.
After the completion of the deflashing operation,
the lower gate 33 o~ the vestibule V may be opened to
the phantom line position of Figure 2 (as by the crank
123) and the belt B may be reversed so that the
articles carried by the belt B are transported into
the unloading chamber 16. Subsequently, the gate 33
may be returned to its initial position to prevent the
escape of the cryogen gas, and the lower closure panel
23 may be manually opened to remove the articles from
the apparatus.
; As will be recognized by the apparatus disclosed
in Figures 1 through 6, the icing and safety hazard
associated in the prior art apparatus are significantly
eliminated with the vestibule V preventing cryogen~
atmosphere interaction and cryogen exposure to operating
personnel.
In Figure 7, a modified vestibule or gas lock
- 25 arrangement is illustrated which may be substituted
for the vestibule V of Figures 1 through 6. By this
particular modification, the loading bin 237 includes
a marginal extension or flange 225 adjacent one edge
thereof which engages a sealing member 232 formed on
30 the interior surface of the door D. Similarly, a
lower seal 232a is mounted on one surface of the
partition 17 which in combination with the seal 232
forms a substantially gas tight seal between the loading
chamber 15 and the deflashing chamber~ By this
35 particular arrangement, the necessity of having a
separate inner gate 29 (shown in Figure 1) is eliminated
with the rear wall 229 of the bin 237 performing a
comparable function.
4~
17
The modification further provides a baffle
depending downwardly from the top surface of the case
C to deflect articles being tumbled during the de~lashing
operation back onto the concave upper course of the
belt B. The baffle is preferably pivotally connected
intermediate its length such that during pivoting of
the bin 237 to enter parts into the deflashing chamber
(in a manner previously described), the baffle may
extend to a non~restrictive position indicated by the
phantom lines in ~igure 7.
In addition, the modified vestibule structure
includes a lower gate 233 which is pivotally mounted
about an axis 234 for movement between an opened and
closed position indicated by the full and phantom lines
respectively in Figure 7. As shown in its closed
position, the gate 233 mates with a top and side seal
235 and 235a to prohibit interaction and heat transfer
between the cryogen gas and the atmosphere. Further,
the gate 233 serves to redirect any articles back onto
the belt B ~hich accidentally are thrown of~ the belt
` during the deflashing process.
In Figures 8 through 12, a second embodiment for
the deflashing apparatus of the present invention is
disclosed which is particularly suited for completely
automated operation. As shown, the apparatus generally
comprises a casing 300, having inner and outer spaced
walls 302 and 304 respectively, which are preferably
filled with an insulating material. The apparatus
shown is similar to the prior embodiment, and ~urther,
a modified gas lock or vestibule 308, an automatic part
conveyor 312, a belt tensioning means 370a, flash/media
separator 454, and a modified media transport and throwing
wheel assembly 510.
9L~
18
P~eferriny to Figure ~, it may be seen that
the casing 300 is provided with a door
306 which preferably extends across the entire front
surface of the apparatus. The door 306 includes an
outer lock or vestibule 308 which forms a substantially
gas tight loading and unloading chamber 310 and 400
respectively (shown in Figure 11). Manual access to
the chamber 300 is facilitated by an outer hatch 330
which is pivoted to -the top surface of the vestibule
30~ by a hinge 332, whereas access to the chamber 400 is
similarly provided by a pair of pivoted hatches 404.
The chambers 310 and 400 are separated from one
another b~ an automatic part conveyor 312 and are
15 selec~ively isolated from the deflashing char~er 322 by
a pair of gates 324 and 390. The conveyor 312 is
provided with a series of fli~hts 314 extending along
its periphery, which grip and carry the parts along
the conve~or 312. As shown, the conveyor 312 is driven
20 in the direction of the arrow 31~ whereby the parts
carried thereon may be automatically deposited onto
the tumbling belt 320 within the deflashing chamber 322.
. As will be recognized during this transfer of the parts
:~ from the conveyor 312 onto the belt 320, the inner
- 25 gate 324, which in its closed position extends from the
upper portion of the chamber 310 to slightly below.
the uppermost pulley 422 of the conveyor 312, pivots
in the direction of the arrow 326 to reside in a
position indicated by the phantom lines in Figure 11.
30 As such, the gate 324 forms an inner gas lock which
permits limited interaction of the cryogen
environment in the deflashing chamber 322 with the
atmospheric environment of the loading chamber 310
only during loading of articles into the deflashing
35 chamber.
The unloading chamber 400 is additionally
provided with an inner gate 390 forrned having an upper
4~3
19
and lower section 392 and 394 respectively which is
pivotally mounted abou-t an axis 396. As in relation
to the gate 32~, the gate 390 has a closed position
(indicated by the full line in Figure 11), wherein
gate 390 sealingly engages the lower wall of the
chamber 400 to isolate the unloading chamber aoo
from the deflashing chamber and an open position
wherein the gate 390 pivots in the direction of the
arrow 398 to reside in a position indicated by the
phantom lines in Figure 11. In this open position,
the belt 320 may be driven in a reverse direction to
' dump the parts carried thereon into the unloading
chamber 400 in the manner previously described. Thus,
from above, it will be recognized that this second
embodiment also eliminates the safety hazards of
the prior art by providing a vestibule chamber
308 which permits the loading and unloading of articles
in the apparatus without direct exposure to the
: 20 cryogenic gas environment within the deflashing chamber.
As in the previous embodiment, the deflashing
chamber 322 includes a plurality of axles 350, 352 and 354
which support the belt 320 on sprockets respectively
numbered 356, 353 and 360. These sprockets allow the
belt 320 to travel in a substantially L-shaped
configuration t~hereby the parts (not shown) may be
tumbled in the concave pocket formed upon the upper
: course of the belt 320 by the pair of discs 342.
In this embodiment, however, the belt 320 is
tensioned by means of a roller 364 which is mounted
about an axis 366 to a support arm 368. The arm 368
is formed in a dog-leg configuration with the upper
portion being connected to a rod 370 that is in turn
mounted to a spring 373 and cylinder 374 arrangement.
The spring 372 biases the rod 370 to provide continuous
tension on the belt 320. In this manner, when the belt
320 either expands or contracts in response to the
introduction or elimination of cryogen gas within the
deflashing chamber 320, the belt achieves a degree
48
of automatic tensioning due to the biasing force of
the spring 372. As such, the substantial thermal
contraction of the belt during operation, which often
; 5 caused premature failure of the belt 320 in the prior
art, has been compensated for in the present invention.
To ensure that the articles are continuously
tumbled on the belt 320, a deflector 378 is additionally
provided, being positioned at the interface between
10 the vestibule 308 and the deflashing chamber 322. The
deflector 378 preferably comprises an upper portion
380 and a lower portion 382 connected at a hinge point
384. The upper portion 380 is additionally connected
by a hinge 386 for upward pivotal movement in a
15 direction of the arrow 388 to a position indicated by
~ the phantom lines in Figure 11. When dis~osed
j in its closed position, the leg 380 is
angularly inclined toward the belt 320, thereby
;i~ urging parts accidentally thrown thereon back onto the
20 belt whereas in its open position, the leg 380 extends
outward away from the belt 320, thereby permitting the
deflashed articles to be dropped into the unloading
chamber 400, without interference from the deflector
380.
Referring to Figures 9, 9a, 9b and 10, the detailed
construction of the second embodiment of the media feed s~rew
and throwing wheel assembly of the present invention
may be described. As shown, the assembly is mounted
to the top surface of the casing 300 in a similar
30 manner to that previously described, with the throwing
wheel 510 being aligned with a discharge opening
extending into the deflashing chamber 322. However,
in this embodiment, the helical feed screw 50~ and
impeller 510, although being axially aligned, are
35 driven by separate motor drives such that their
rotational speed may be independently variable. As
- f: (
21
will become more apparent below, this independent
drive feature permits the apparatus to be finely
adjusted to specifically meet the performance
. 5 requirements necessitated by individual part
configurations.
eferring more specifically to Figure 9 and 9a, it
may be seen that the distal end of the tube S21
surrounding the feed screw 504 is provided with a
collar 516 having a small opening 520 therein which
allows the media to be delivered into the radially
oriented spaces 524 formed between the vanes 526 of
the throwing wheel or impeller 510. As in the previous
embodiment, this collar 516 may be rotated about its
central axis to vary the angular orientation of the
opening 520 with respect to the throwing wheel or .
impeller 510.
:~ It will be understood that a relationship
exists between the point of introduction of media into
a throwing wheel and the point of discharge of the
media from the vanes of the throwing wheel (i.e., the
direction of the media exiting the throwing wheel is
dependent upon the angular orientation of the point of
introduction o-f the media into the throwing.wheel).
Further, as previously mentioned, it has long
been known that in throwing wheels having uniform
length vanes 526, the media discharge from the wheel
is not uniformly distributed, but rather is concentrated
within a localized area of the discharge pattern
typically designated as a hot spot.
- ~ (
4~
To properly direct the media stream and substantially
eliminate the concentration problems associated
with the prior art throwing wheel apparatus,
the present invention incorporates a control cage 516
which may be rotated during machine operation to
continuously vary or oscillate the angular orientation
of the opening 52a with respect to the impeller 510.
In such a manner, the hot spot may be continuously
shifted across the area of the de~lashing chamber 322
thereby promoting uniform and consistent deflashing
operations.
Referring to Figure 9a, it may be seen that in
the second er~odiment, the collar 516 includes a
flange S17 adjacent the opposite end from the opening
~ 520~ This flange 517 mounts a lever arm 518 extending
- radially therefrom. The lever arm 518 includes an
aperture 519 which is sized to receive one end of an
actuator rod 523 of a pneumatic or hydraulic cylinder
525 pivotally attached to the casing 300. The rod 523
is attached to the lever arm 518 by a pair of fasteners
527 threaded onto the rod 523 and positioned on opposite
sides of the handle 518. As is well known, such a
fastening arrangement permits the location of the handle
518 to be adjusted along the length of the rod 523.
In operation, the cylinder 525 is energized by
selective pressurization and depressurization from a
controlled external pneumatic or hydraulic actuator
(not shown) to reciprocate the rod 523 thereby causing
the collar 516 to rotate (in a direction indicated by
the arrow in Figure 9a), throughout a predetermined
angular rotation consistent with the width of the
deflashing chamber 322. By this rotation, the angular
orientation of the opening 520 relative the throwing
wheel 510 is varied, thereby shifting the area of
media concentration across the width of the deflashing
chamber 322.
In Figure 9b, a schematic representation of the
; media pattern produced by the apparatus of Figure 9a
is depicted. With the opening 520 of the control cage
or collar 516 disposed in position A, the media
discharged from the impeller 510, although typically
10 being dispersed throughout the deflashing chamber 322,
is concentrated at the localized area indicated by the
numeral MA. Subsequently, with the opening 520 being
angularly rotated to the position B, the media is
concentrated at the area MB located to the right (as
15 viewed in Figure 9b) from the area MA. Similarly,
the concentration of media discharged from the impeller
510 for the positions C and D of the opening 520, are
indicated by the numerals MC and MD, which are located
to the right of the previous media concentration area.
In the preferred embodiment, the c-~linder 525 is
continuously pressurized and depressurized to oscillate
I the opening 520 of the collar 516 throughout the sweep
¦ of the positions A through D indicated in Figure 9b.
As such, the media concentration area or hot spot is
25 continuously shifted throughout the length o the
deflashing chamber 322. Thus, the parts or articles P being
; tumbled upon the belt 320 are uni~ormly deflashed
during operation with the inconsistencies in component
wear additionally being eliminated.
To augment the improved uniform media pattern
produced by the oscillating control cage or collar 516 r
the present invention additionally includes an
improved transport mechanism 506 which is independently
driven from the throwing wheel 510 to deliver a
35 consistent quantity of pellets to the throwing wheel
510 and eliminate the tendency of the media (not shown)
to clog during transport from the hopper. As shown
2~
; in Figure 9, a helical feed screw 504 is positioned
coaxial with the throwing wheel 510 being connected at
one end to a motor by way of a suitable flange
arrangement and terminating at its other end adjacent
the opening 520 of the control cage or collar 516.
The feed screw 504 is enclosed within a tubing
member which, as in the previous embodiment, i~cludes
a media inta~e opening adjacent its top surface. A
media hopper 502 is positioned above the media opening
to store a predetermined quantity of media therein.
In the preferred embodiment, the hopper 502 includes a
level indicator and valving arrangement (not sho~n)
which regulates the amount of media entered into the
hopper 502 to provide a constant static head.
In operation, the feed screw 504 rotates under
the power of the separate motor drive causing media
(not shown) from the hopper 502 to travel first
downwardly into engagement with the feed screw 504, and
- 20 then transverselY towards the collar 516.
Due to the constant static head maintained
within the hopper 502, the amount of media entering the
feed screw 504 will be uniform. Further during this
operation, the throwing wheel 510 being powered by its
separate motor drive, is typically rotated at a RPM
value su~stantially higher than rotation of the
feed screw 504. This rotation develops a vacuum at
the opening or port 520 of the collar 516 which acts
through the collar 516 and feed tube surrounding the
feed screw 504. As such, the media being transported
laterally by the feed screw 504 is vacuum assisted in
its travel and urged through a port 520 onto the
throwing wheel 510.
Thus, by this particular arrangement, the media
is constantly being acted upon during transfer rrom
the hopper 502 to the impeller 510 (i.e., first
downward by the force of the static head within the
hopper 502, second transversely by the rotation of
the feed screw 504, and thirdly transversely and
upwardly through the opening 520 by the vacuum
generated in the throwing wheel 510). As such, the
inconsistent amount of media delivered to the impeller
as well as the clogging problems associated in the
prior art, are substantially eliminated
Further, this particular transport throwing
wheel arrangement permits the apparatus to be finely
adjusted for particular deflashing operations. As
will be recognized, the amount of vacuum assist, as
well as the velocity of the media from the throwing
wheel 510, is related to the speed of the throwing
wheel 510, which ma~ be independently controlled and
varied during operation. Further, the amount of media
being supplied to the wheel 510 is dependent upon the
speed of the helical feed screw 504, which is
additional]y independently variable. Thus, b~ way of
the present invention, the density, intensity, and the
pattern of the media stream, may all be varied to suit
the particular deflashing operation.
In Figures 8 and 12, the media reclaim and media/
flash separator mechanism of the pre-sent invention is
illustrated. Referring particularly to Figure 8, it
may be seen that the lo~er portion of the deflashing
chamber 322 is provided with an inclined member 440
which terminates in a hopper area. As shown, the hopper
includes a transport screw 442 which is driven, as in the
prior embodiment, to feed the media into a reservoir
container 444. The container 444 is in turn connected
to a flexible conveyor m2ans 446 (analogous to the conveyor
previously descri~ed in relation to Figures 4 and 5)
having a helical feed means turned by a motor 448,
to lift the media delivered by the screw 442
upward in tne direction of the arrow 452, and deposit
t'ne same into the separator apparatus.
433
26
The separator apparatus of the present invention
basically comprises a plurality of vibratory chambers
- 454, 456, 458 and 460, each being provided with the
respective screen thereunder, which is graduated in
size from the upper to lower chambers.
In operation, the media transported through the
helical feed tube 452 enters the upper chamber 454
and passes through a respective screen to the lowr
chambers 456 and 458. Each of the lower chambers 456
and 458 are connected as by way of conduits 464 and 46Z
to the conical-shaped hopper 484. Due to the hopper
484 being maintained under vacuum, the meaia within
the chamber 456 and 458 is rapidly drawn off and
transported through the tubes 464 and 462 into the
hopper 484.
The uppermost and lowermost chamber 454 and 460,
respectively, are connected as by way of conduits 466 and
457 to a flash residue container 470 which is similarly
maintained under vacuum. As such, the relatively
large particles of flash which fail to pass through
the larger mesh screen of the first chamber
454, are directly drawn out of the chamber 454,
whereas the relatively smaller particles of flash which
have travelled to the lowermost chamber 460 are
accumulated and similarly removed from the chamber
460.
From the above, it is evident that the
graduation of screens can be utilized in any suitable
manner to allow for the most advantageous separation of
the flash and media. Ho~Jever, the order of the chambers
and their respec-tive screen size is preferably maintained
such that the gauge of opening in the screen decreases
from the upper to lower chambers of the separator to
35 eliminate the smallest flash particles at the lowermost
chamber while drawing off the media from at least one or
two of the chambers thereabove. In such a manner, a
g~
suitable separation between the media and flash of the
system is accomplished.
Subsequent to the separation process, the media
falls into a conical-shaped hopper ~84 which is
supported by legs 4gO and ~82. The hopper ~8~ is
connected to a feed screw and conveyor assembly ~90
that is of the helical screw type ~46 previously
described for conveying the media upwards into the feed
hopper 502 of the -throwing wheel assembly 510.
The applicant has found that when the media reaches
this hopper 482, its temperature has typically been
raised to an intermediate level, i.e., between the
cryogenic temperature and the atmospheric temperature,
which often attracts moisture and creates a frost
condition. As a consequence, it is advantageous that the
media should be heated to evaporate any moisture contained
thereon or alternatively maintained at cryogenic
temperatures throughout the entire deflashing process
to avoid icing. As such, in the preferred embodiment,
the hopper 44~ is provided with a cal rod ~94 which is
connected to a power supply as by way of the electrical
leads 496 to heat the media to a temperature above the dew
point. Alternatively, the entire conduit 446 leading to the
separator apparatus could be maintained at temperatures
approaching the cryogenic temperatures, whereby the formation
of ice would be prohibited. Thus, the separator apparatus
of the present invention substantially separates the
media from the flash liberated in the deflashing
process and prevents a forrnation of ice on the media
being transferred back to the throwing wheel apparatus 510.
From the above, it will be recognized that the
embodiment of Figures 8 through 12 is particularly
suitable for completely automatic operation. In this
regard, it is evident that the opening of the outward
hatch 330 of the vestibule structure 308 may be readily
accor~modated by pneumatic or hydraulic rneans such as
a hydraulic actuator ~10 extending therefrom and
'' ` ( I'
;
28
interconnected to the door by way of a pivot point 414
In addition to the foregoing pneumatic or hydraulic
cylinder 410, there can be various other means
` - 5 such as a rack and pinion or individual motor drives (not
; shown) incorporated within the sidewalls 302 and 304 of the
casing 300 to drive the inner gates 32a, 380 and 392
between open and closed positions. Similarly, the
speea of the motors, as well as the operation of the
control cage 516, may be controlled by the use of a
variety of electrical or electromechanical linkages.
As such, all the elements of the apparatus can be
advantageously automated and connected to a digital
control sys-tem (not shown) for providing a timed
processing of material or articles through the apparatus.
i, Thus, the system can function entirely under
automatic control down to the point of loading and
unloading on a conveyor. As a consequence, the present
invention provides a substantial improvement over the
prior art deflashing apparatus.
LJK/K~IS:jl/pb
