Note: Descriptions are shown in the official language in which they were submitted.
ELECTRIC MELTER NEEDLE MOUNT AND DRTVE
Technical Field
This invention relates to electrical melting furnaces and
more particularly to an apparatus for controlling the mass flow rate
of molten material through the furnace.
Back~round o~ the Invent~2n
Electrical open-top melting furnaces having primary
electrodes that are shaped and mounted in such a manner that they enter
the furnace through the furnace top are known in the art as evidenced
by U.S~ Patent Nos. 3,983,309 and 2,978,526. Generally/ these furnaces
utilize several electrodes spaced around an outlet mEmber that also
acts as an electrical conducting member operating with the electrodes
to form a current flow pattern. These furnaces also utilize a melter
needle, usually made of molybdenum, in order to control the mass flow
or the pull rate of the molten material flowing from the furnace.
; 15 Conventionally, the position of the melter needle tip relative to an
orifice in the outlet member is controlled by hand or by utilizing
a suitable motorized drive mechanism. However, these prior melter
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- needle control mechanisms were cumbersome, inaccurate in that they
- could not provide a linear displacement of the melter needle in
incremental amounts, e.g., of about .010 inches, and could not provide
a means for rapidly retracting the melter needle from its operational
position in the furnace during emergency or routine servicing of the
melter needle.
~rief Summarv of In~ention
Accordingly, it is an object of the present invention to
provide a melter needle assembly for adjusting the operational position
of the melter needle relative to the outlet orifice in an electric
melting furnace. The operational position is generally fixed for
a given set of operatlonal parameters (pull rate, etc.
It is another object of the present invention to provide
a melter needle mount and drive capable of producing an incremental
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and relatively small linear displacement of the melter needle with
respect to the orifice in an electric melting furnace.
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A further object of the present invention is the provision
of a mslter needle assembly which allows quick and ready sarvicin~ of
the melter needle.
Still another object of the present invention is the
provision of an incremental drive for controlling the position of the
melter needle relative to the outlet orifice of an electric meltinO
furnace.
These and other objects are attained in the `present
invention by means o an apparatus for controlling the position of a
flow obturator or needle relative to the outlet orif iC8 of an
electric melting furnace, comprising a support and an I-beam mounted
at one end on and extending Prom the support to a proximate position
~Ibove the orifice. An incremental motor drive is mounted on the
I-beam at the proximity of the support and drives a command shaft
eithar incrementally when the needle is in its operational position
or very rapidly when tha needle requires routine or emergency
servicing. A rotary to linear motion converter mounted on the other
end of the I-beam causes a movable needle mount to ~ertically
translate either toward or away from the outlet orifice. The needle,
which is mounted on the movable mount, is provided with a radial and
lateral adjustment, which ensures colinearity of the center lines of
the needle and orifice, and a vertical adjustment that is capable of
initially positioning a needle relative to the orifice aÇter the
needle has either been replaced or otherwiss serviced.
When routine or emergency servicing oP the needle is
demanded, a motive fluid operates on a pisto~ to cause the I-beam to
vertically translate so that the needle may clear the uppermost
surface of the furnace. A release mechanism allows the I-~eam to be
rotated by a rotary device to its retracted position.
The incremental needle drive of the present invention
comprises a motor whose torque is reduced and transmitted via
couplings to a shaft wbich ePfects an upward mov~ment of the needle
and to a shart which effect~ a downward movement of the needle. An
electromechanical clutch brake and an electromagnetic clutch coupling
are mounted on both the up shaft and the down shaft to ansure that
the angular rotation oS the command shaft is incremental.
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Brief Desc~iption of Drawinqs
FIG 1 is a schematic view, in side elevation, of the melter
needle assembly of the present invention
FIG. 2 is a schematic plan view illustrating the needle
oxientation in its operational and retracted positions.
FIG. 3 is an enlarged cross sectional view taken alon~ the
line 3-3 in EIG. 1.
FIG. 4 is an enlarged view of a portion of the embodiment
shown in FIG. 1 and better showing the needle radial adjustment means.
FIG. 5 is an isolated view of the mounting bracket shown
in cross section in FIG. 3.
FIG. 6 is a plan view of the mountin~ bracket illustrated
in FIG 5.
FIG 7 is a schematic side elevational view of the needle
head subassembly.
FIG. 8 is a frontal view of the needle head subassembly.
FIG. 9 is a cross sectional view, with parts broken away, of
the gear box shown in block form in FIG~ 7.
FIG, 10 is an enlarged view of the cross section taken along
the line 10-10 in FIG. 8.
FIG. 11 is a plan view of the motorized incremental needle
drive.
FIG. 12 is a side view of the ~otor drive illustrated in
FIG. 11.
Detailed Descri~tion of the Pre~e~ed Ehbç~1s~n~
Referring now to the drawings wherein the same numerals refer
to like elements, FIG. 1 shows the melter needle assembly of the
present invention installed beside a conventional electric melting
furnace or melter 10. Typical of an electric melter furnace which
may utilize the present invention is shown in U.S. Patent No. 3,983,309
issued September 28, 1976 to Faulkner et al and U.S. Patent No
4,159,392 issued June 26, 1979 to Fineo et al.
The furnace 10, partially shown in FIG. 1, is comprised of
a container for molten material 12 having a top crust level or melt
line 14, a plurality of primary electrodes (not shown) and a central
electrically conducting outlet member 16. The container for the molten
material comprises an outer metal shell 18 which can be water cooled
by any conventional means, particularly when melting materials at a
; temperature above 2000F. The metal shell 18 may be lined with a
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layer of suitabl~ refra~tory material (not shown) compatible with the
matPrial being melted ~n the furnace lO. The electrically conducting
outlet member 16 is supported in the proper position by a metallic
cone 20 preferably made of a refractory metal like molybdenum,
tungsten, or t~ltalum. This metallic cone is in turn supported by a
water cooled me~allic lower cone (not shown) usually made of a high
heat conductive material such as copper. The melter 10 also
comprises a number of rings, the upper surface of which is
rPpresented by line 21 in FIG. 1.
~he melter needle assem~ly is partially disposed outside of
the melter 10 and partially disposed above the outlet member 16 and
comprises a ram subassembly 22, a boom subassembly 24 mounted on the
ram subassembly 22, a motorized incremental needle drive 26 mounted
at one end of the boom subassembly 24, a needle head subassembly 28
mounted at th~ other end of the boom subassembly and vertically
disposed above the outlet member 16, and a flow obturator or needle
The needle 30 cooperates with an orifice 32 formed in the outlet
member 16 to control the mass flow rate or pull rate of the molten
material flowing out of the melter lO through the outlet member 16.
The pull rate of the melter 10 is controlled by translating
the needle point 34 within the orifice 32 whereby the efective flow
passage defined between the needle point 34 and the orifice 32 is
adjusted. Subtle differences in the positioning of the needle point
34 relative to the orificQ 32 ha~e a profound effect on the pull rate
of the melter 10. Therefore, it is a ~oal of the present invention
to provide an incremental translation of the needle point 34 relative
to the orifice 32.
It is also a goal of the present invention to provide a
means for raising the needle 30 above the uppcr surface 21 of the
rings forming part of the meltqr lO and rotating the needle out of
t~le melter so that the needle 30, which may be made of a highly
~xidizable material such as molybdenum, may be serviced. In routine
as well 8S emer~ency situations, the present invention also provides
a mea~s for rapidly moving the needle 30 out of the melker lO such
that tlle molybdenum ~eedle material is not rapidly oxidized in the
oxidizing atmosphere present proximate the melt line 14. Such a
means is provided, in part, by the ram subassembly 22.
Ram subassembly 22 is comprised of a weldment or ram basl 36
which is molnted on the floor or melter plat~orm 38 by means of
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a ram mounting plate 40 and vibration mounts 42 which are juxtapos~d
between a ram base plate 44 and the ram mountin~ plate 40. A
stabilizing trunnion mount 46 is fixedly attachPd to the bas~ plata 44
and suitably supports a cylinder 4B which slidingly supports a piston
49. The piston 49 prcvides a means for rapidly moving ths boo~
subassembly 24 in a vert.cal direction away from the o~tlet member 16.
A motive fluid capable of causin~ the piston within the cylinder 48 to
ris~, the~eby causing the boom assembly ~4 to also rise, is supplied to
the piston by a source of fluid unde~ pressure ~not shown) via a
conduit 47. The pressure may be regulated to contral the ram forca
supplied by the motive fluid operating on the piston 49 so that in the
event that tha molten material freezes c~used by, e.g., a malfunction
n an electrode, the mel er needle assembly will not be damaged.
Attached to the upper portion o~ the piston 49 is a head plate
50 to which is attached by means of lock nuts 52 an alignment shaft ~4
which is slidingly supported by an alignment shaft cylinder or bushing
56. The bushing 56 is fixed to the ram base 36 by means of a bracket
(not shown) and a fastener 58. ~e bushing 56 allows the shaft 54 to
stabilize the vertical movement of the boom subassembly ~4 as it i5
translated by the piston 49 within the cylinder 48. Suitable sensors
(not shown) are mounted on the ram base to detect the fully up and
fully down position of the shaft 54.
Fastened on the upper surface of the head plate 50 is a rotary
actuator 58, a pair of shock absorbers 60 (only one of whic~ is shown
in FIG. l) and a pilot mounting bracket 62. The rotary actuator 58
cooperates by ~l~ans of a shaft (not shown) with a boom top plate 64
mounted underneath the boom subassembly 24.
The rotary actuator 58 is capable of movin~ the boom
subsssembly 24 and consequently the needle head subassembly 28 and
needle 30 from an operational position shown in solid lines in FIG. 2
to a retracted position shown in phantom in that same fi~ure via a
baar~ng pl~te 65 and a rotary air bearing 66. The shock absorbers 6~
decelerate the rotational movement of the boom subassembly 24 as it
rotates either from the operational position to the retracted position
or from the retracted position to the operational position.
When in the operational position, a solenoid operated pilo~
67, mounted on the bracket 6Z, is aGtivated and a pilot plunger 68
translates upwardly in order to enga~e a bushing (not shown) fixed
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in the top plate 64 thereby lockin~ the boom subassembly 24 in its
operational position. Of course, when it is desired to rotate the boom
su~assembly 24 to its retracted position, the plunger 68 would be moved
downwardly to a position where it no lon~er engages the hushing fixed
in the top plate 64. Attached to the boom subassembly 24 is a bracket
70 which mounts conventional proximity switches (not shown) which
detect the up and downward movement of the plunger 68.
As was noted, the boom subassembly 24 is mounted on the top
plate 64 and comprises an elon~ated member or I-beam 76, an adjustable
counterweight 78, a needle head subassembly-boom subassembly cGupling
means 80 and a needle radial adjustment means 82. The center of
gravity of the melter needle assembly of the present invention is
adjustably controlled utilizing the counterweight 78 ~hich is affixed
on the bottom flange of one end of the I-beam 76. ~he counterweight 78
lS is made adjustable by means of a threaded counterweight adjusting shaft
84 which is suitably rotatably supportPd by means of a shaft bracXet 86
and a block 88. As the shaft 84 is rotated the position of the wsight
78 may be varied in order to shift the center of gravity of the entire
assem~ly.
The c~up].ing means 80 is disposed at the other end of the
I-beam 76 and is shown in FIG. 3 as comprisin~ a sliding plate 92,
attachment screws 94, ~uides 96, a mounting bracket 98, and clamp
screws 100. The sliding plate 92 is affixed to the upper flange of the
I-be2m 7~ by msans of a suitable attachment means quch as the
attachment screws 94. The sliding plate 92 is capable of a sliding
move~lent within ths guides 96 which are disposed at opposite ends o
the plate 92. The guides 96 are suitably fixed within the mountin~
bracket 98 by means of the clamp screws 100 that are passed through
bores 102 formed in gussets 104 (see FIG. S) and are locked in placs by
means of lock nuts 106. The gussets 104 are fixedly attached to a
mounting bracket back plate 108 and an upper plate 110.
Threadi~gly passing through the I-beam 76 and adjustably fixed
at its ends between gussets 104 is a lateral adjustment screw 112. ~he
lateral adjustment screw 112, which passes through holes 113 formed in
3S each of the gussets 104, allows an adjust~ent in the lateral
orientation of the mounting bracket 98 relative to the I-beam 76 so
that the neP,dle 30 may be properly laterally oriented within the outlet
member 16~ A suitable head 114 Pacilitates the rotation of the
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adjustment screw 112 and locX nuts llS fix the adjustment screw in the
desired position.
A'fixed atop the upper flan~e of the I-beam 76 is a blocX 118
(see FIG. 4) which rotatably supports one end of a radial adjustment
shaft I2Q. The radial adjustment shaft 120 is fixsd at its one end by
means of a p~ir of clampin~ collars 121. The other 8nd of the radial
adjustment shaft 120 is rotatably suppo~ted by a nut 122 which
slidingly bears down on the upper ~urface of the slide plate 92. The
nut 122 fits within a transverse portion 124 of a cross shaped slot 126
formed in the upper plate 110 of the mounting bracket 98 (see FIG. 6).
A dust cover 128 is suitably attached to the upper plate 110 by means
of a plurality of bclts 130 which fit i~ bores 132 in the plate 110.
As FIG. 4 shows, when the radial adjustm~n~ shaft 120 is
rotated about its axis the distance bet~een the block 118 and the
sliding bearing nut 122 msy be varied. Therefore, since the nut 122
travels within the tranverse portion 124, the mounting bracket 98 may
be moved relative to the I-beam 76. This movement allows a radial
adjustment on the orientation of the melter needle 30 relative to the
orifice 32 so that the center line of the melter needle 30 and the
center line of the orifice 32 may be aligned radiaIly.
Referring now to FIGS. 4 and 9, the plate 108 of the mountin~
bracket 98 is illustrated as being ~ixedly attached to a vertical plate
134 of a stationary needle drive mount 136, forming part of the needle
head subassembly 28, by means of bolts 138 which pass through mounting
hol~s formsd in the plate 134 and in the back up pl~te 108. An
electrical insu;ator 140 is juxtaposed between the plate 134 and the
plate 108 and serves to electrically isolate the boom subassembly 24
from the needle head subassembly 28 which is illustrated more cleasly
in FIGS. 7 and 8.
~he needle head subassPmbly oomprises a miter ~ear box 142,
the statlonary needle drive mount 136, a movable needle support and
vertical adjustment means or moveable mo~nt 144 and a needle vertical
adjustment means 146. As FIG. ~ shows, tha needle drive mount 136
comprises an upper and lower plate 148 and }50 fixedly attached to the
vertical plate 134. The lower plate 150 is shown in FIG. 10 as a
generally T-shaped plate having a fillet 149 in order to reduce stres~
concentrations. The upper plate 148, which ls substantially similar to
th0 plate 150, is provided with a bearin~ boss 152 to allo~ freepassage
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of a rotatable vertical adjustment shaft 184 while the lower plate 150
is provided with a clearance 212 which allows for th~ ree passage o
the shaft 184. Both the upper and lower plates 148 and 150 are
provided with bushir.~s 182 which allow free movement of a pair of ~uide
shsfts ~08. A pair of guæsets 151 are fastened perpendicular to both
of the plates 148, IS0 and to the vertiral plate 13b. ~e miter gear
box 142 sits atop the upper ~ur~ace of the upper plate 148.
FIG. 9 shows the miter gear box 142 in cross se~tion ~ith
parts broken away and comprises the bearing boss 152 which is fixed in
a hole 154 formed in the upper plate 148. The bearing boss 152
rotatably supports a first miter gear 156 by means of thrust bearings
158. The miter gear 156 interga~es a second miter gea~ 160 which is
rotatably fixed on a command shaft extension 162 by m0ans of a roll pin
163. The extension 162 is coupled by means of a flange 166 to a flange
168 formed on a command shaft 164 (see FIG. 4) which is dri~en by the
motorized incremental needle drive 26. An electrical insulator 170 is
juxtaposed between the flanges 166 and 168 and is clamped in place by
means of bolts 172. The command shaft extension 162 is rotatably
supported by means of bearings 174 which are clamped in place by means
of a bearing housing 176. The housing 176 is elamped to a block 178
that is fixed on the plate 148 by means of bolts 180.
Coupled to the first miter 8ear 156 is the vertical adjustment
shaft 184 which forms psrt of the movable needle support and vertical
ad~ustment means 144. The vertical adjustment shaft 184 is suitably
threaded (e~B~, an Acms thread) so as to fit within an internally
threaded bors 186 of the miter ~sar 156.
A purge housing 188 is fitted about the miter ~ear box 142 and
provides a means of preventing furnace dust from e.nterin~ the
mechanical workings of the miter 8ear box. Purge housing 188 comprises
sheet metal which is attached to the plate 148 and to the bearing
housing ~76. An enlar~ed hole 190 allows free passage of the vertical
a~lustment shaft 184 and a port 192 conducts the flow of purge air into
the housing 188 by means of a flexible hose 194 which is coupled to a
source of air undsr pressure (not shown). The flexible hose 194 is
appropriately attached to the I-Beam 76. The air enterin8 the houslng
188 pressurizes the housing and flows through the hole 190 and through
passa~eways 146 and 198 which are formed in the bearin~ bo~s 152. Th~
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passage of the pressurized air through the housing 1~8 ensures that any
dust possibly interfering with the mechanical operations of the miter
gear box 142 will be carri2d out of the housing 188,
The movable needle support and vertical adjustment maans 144
5 comprises the vertical adjustment shaft 184, an upper tube brac~et 200,
a lower tube bracket 202, a left hand an~le support bracket 204, a
ri8ht hand an~le support bracXet 206, the guide shafts 208 and a
support tube 210.
The drawings illustrat~, in FIGS. 7 and 8, a clampin~ block
214 being rotatably fixed to one end of the vertical ad~ustment shaft
184 and to one of the ends of each of the guide shafts 208. As more
appropriately shown in FIG. 10, the lo~er tube brac~et 202 and thus the
equivalent upper tube bracket 200 are generally U-shap~d and are
provided with two ears 213 which ar~ fixedly attached to the ~uide
shafts 208 using an approprlate fastenin~ ~eans such as bolts 215.
Each of the brackets 200, 202 are provided with a tube mounting cut-out
216 which allows the ~nsertion of the s~pport tube 210, In abuttin~
contact with the support tube 210 and adjustably mounted on each of the
brackets 200, 202 is a non-metallic tu~e mounting blocX or isolator 21
which electrically isolates the support tube 210 from the brackets 200,
202.
The left hand angle support bracket 204 and the right hand
angle support bracket 206 are ~ixedly attached to the upper and lower
tube brackets 200, 202 by means of bolts 220. The support brackets
204, 206 provide the support for a ~eans for removably fixing ths
support tube 210 against the tube brackets 200, 202 and the electrical
isolator blocks 218. Support tube 210 i9 remova~ly fixed by means of a
clamping plate 222 which i5 pivotably fixed at one end by means of a
bolt 224 which passes through a bushing 226 that is fixed in the plate
222 and a nut 223 fixed on the left hand support bracket 204. The
other end of the clamping plate 222 is:ramovably fixed to the right
hand support bracket 206 by means of a clamping knob 230 that i8
threadingly fitted within a flange of the right hand support brac~et
206. An lnsulating pad 232 electrically isolates the clamping plate
222 from the support tube 210. ~uring sarvicing, an access door 231
allows the clampislg plats 222 to be released by an appropriate rotation
of tha clamping kno~ 230. The plat~ 222 pivots downwardly about the
bolt 224 to a vertical position under the influence of gravity whereby
t~e tub~ housi~g 210 may be rem~e~
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In order to prevent dust from contaminating th~ sliding parts
of the movable needle support and vertical adjustment ~eans 144, sheet
metal 234 is provided. Bott~m cover 236 protects the workinOs o the
guide shafts and the lower portion of the vertical adjustment shaft
5 184, as shown in FIG. 7. Both the sheet m~taL huusing 234 and the
bottom cbver 236 are pressurized with air in a manner not shown in
order to purge these compartments of any dust which may migrate from
the furnace environment.
Fixed at the lowsr portion of the support tube 21Q is a plug
238 which is fixedly attached to an upper block 240. The upper block
240 is adjustably fixed to a interma~iate block 242 by means of a key
fittin~ (not shown) and adjustable screws 244. The adjustable screws
244 are utilized to force the intermediate blocX 242 to translate left
or right as shown in FIG. 8 with respect to the upper blocX 2~0 in
order to ensure that the center line of the support tube 21Q is
~aterally aligned with the centsr line of the nee~le 30. These scr~ws
244 are locked in their final position using fasteners 245. ~he
needle vertical ~adjustment means 146 comprises a needle holder or
weldment 246 which is fixedly at~ached to a lower ~ortion ~f the
intermediate blocX 242 and provides a support for an upper coolin~
tube clamping blocX 248 and a lower cooling tube clamping blocX 250.
Cooling tubes 252 and 254 are clamped to and pass through clampin~
blocks 248 and 250. Ad;ustably clamped about the coolino~ tubes 252,
254 is an adjustable bar or needle vertical adjustment block 256. The
upper portion of the needle 30 is fixedly ~ttached to the adjustment
bar 256 by any suitable means such as a collar tnot shown~. The
adjustment bar 256 is removably fixed to the tubes 252, 254 by means
of set screws 258. W~en set screws 258 are released the adjustment
bar 256 may slide on the tubes 252, 254 and thus the nee~le 30 may be
sd~usted vertically relative to the needle holder 24~. This
adjustment facilitates the vertical positioning of the needle point 34
relative to the orifice 32 when a needle 30 is first installed in the
~furnace 10 either after replacement of a former needle 30 or servicing
of the needle.
A coolin& can 259, fixed by means of a loc~ nut 260 o~ the
needle 30, is nominally disposed at the melt line 14 of the furnace 10
and is supplied with a cool~nt such as water by me~ns of the cooling
t-~be 252. The coolin~ can 259 protects the molybdsnum needle 30 from
the harmful critical oxidation temperatures experienced at the melt
line 14. The cooling tube 254 provides a means of retur~ing ~he spent
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and now hot coolant to a suitable heat exchanger (not sho~l). As is
shown in FIGS. 1 and 3, the cooling tubes 252, 254 are suitably affixed
on the I-beam 76.
Turning now to FIGS. 11 and 12, the motorized needle drive
26 is illustrated. ~s shown in the figures, a bi-directional, constant
torque DC motor 262 is mounted on a drive mounting plate 264 which
is fixed to the upper flange of I-beam 76 by means of a fixture 266
and a stand off support 268. me motor 262 is capable of operating
at a relatively low rotational speed, e.g., 150 RPM and at a relatively
high rotational speed, e.g., 700 RPM. There is a need in the present
invention for these two speeds because at the relatively low rotational
speed, an incremental displacement of the needle 30 may be effected.
It is necessary at times, e.g., during routine or emergency servicing
for the melter needle to be rapidly removed from the environs of the
furnace because the molybdenum, consituting the highly oxidizable
material of the needle 30, must be removed very rapidly from the highly
oxidative atmosphere present proximate the melt line 14 of the furnace
10. At these times the motor must be capable of the relatively high
rotational speed. The motor output shaft 270 is fixed to a torque
limiting coupling 272 whose output shaft 273 is rotatably supported
on pillow block bearings 274. The torque limiting coupling 272 is
included as a safety device m the drive train of the melter needle
assembly. Should, for example, the needle so jam or molten material
freeze, this coupling would slip avoiding serious damage. Fixed on
the shaft 273 is a small up mode pulley 276 and a s~all down mode
pulley 278.
Small up mode pulley 276 is coupled via belt 280 with a large
up mode pulley 282 which is fixed upon an up mode shaft 284. The shaft
284 is rotatably fixed on two pillow block bearings 286 and is provided
intermediate the two bearings 286 with a conventional electromechanical
clutch brake 288. The end of the shaft 284 is provided with a
conventional electromagnetic clutch coupling 290 whose output shaft
is coupled with the command or output shaft 164 by means of a pulley
292, a belt 294 passing through an opening 295 in the plate 264 and
a pulley 296 which is fixed about the command shaft or output shaft
164. m e command shaft 164 is rotatably supForted upon the drive
mounting plate 264 by means of pillow block bearings 298. An
electromechanical clutch brake found suitable for use in the present
invention is sold by the Warner Electric Company, PSI Division under
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the trade name of Incremental Clutch, ~odel # CB-5. An appropriate
electromagr,etic clutch coupling suitable for use in the present
invention is sold by the Warner Electric Company under the trade name
of Warner Clutch, Model # S~400.
Rotational torque provided by the shaft 273 is simultaneously
transmitted via a belt 300 to a large down mode pulley 302. The lar~P
pulley 302 is fixed about a ~own mode shaft 304 which is rotatably
supported by means of pillow blocks 306 fi~ed on tha moun-ting plate
264. A conventional electromechanical clutch bra~e 308, which is
equivalent to the brakP 288, is affixed ahout the shaft 304 and a
conventional electromagnetic clutch cou~ling 310, equivalent to the
couplin~ 290, is affixed about the shaft 304 at its distal end. The
output of the coupling 310 is provided with a pulley 312 which
transmits torque via a belt 314 to a pulley 316 which is mounted upon
lS the command sha~t 164.
The operational modes of the motorized needle drive 26, i.e.,
the up and down modes effectuated by tha up and down mode shafts 284,
304, are ident.ical. Thus, the up mode will only be described for the
sake of economy and will be equivalent to the down mode. In use, the
motor 262, upon activat~on by a controller ~not shown~, continuously
rotates its output shaft 270. The torque produced by the motor 262 is
limited by means of the coupling 272 for the safety of the equipment
and its output shaft 273 rotates the pu118y 276 and the pulley 278.
Pulley 276 causes a rotation of the pulley 282 by means of the belt
280. The shaft 284 is mo~ed at an appropriate spesd by means of the
pulley 282 such that when an appropriate elec~rical signal is rece~ved
from the controller the clutch coupling 290 is activated. Almost
simultaneously the brake 288 receives a si~nal from the controller and
causes its pawl 318 to move out of an engagin~ contact with its
ratchet 320 thereby causing a certain incremental an~ular rotation of
the shsft 284. The pawl 318 is caused to almost immediately return to
its engaging relationship with the ratchet 320 by deenergizing the
brake 288 thereby ensuring an incremental rotation of the shat 284.
Because the coupling 290 has connected the shaft 284 with its output
shaft upon receipt of the signal from the controller the pulley 292
allows an incremental rotation of the command shaft 164 via the belt
294 and the pulley 296 and then is deenergi~ed.
The command shaft 164, connected via universal joints 322
with the command sha.t extension 162, causes an incremental rotation
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of the second miter ~ear 160 which correspondin~ly causes an
incremental rotation of the first miter gear 156. The first miter
gear then effects an incremental translation Oe the vertical
adiustment shaft 184. Since the adjustment shaft 184 is fixedly
attached to the clampinK block 214 the movable needle support and
vertical adjustment means 146 translates upwardly. The phantom lines
in FIGS. 7 and 8 illustrate the means 146 in its most upward
position. Concomitantly the needle 30 i9 also transla~ed upwardly an
incremental distance proportional to the an~ular rotation of the
command shaft 164. Appropriate sensors (not shown) denote the
position of the needle relative to the outlet orifice. In the event
of failure of the motorized needle dri~e, a hand wheel can be us~d to
incrementally move the needls 30.
Durin~ servicin~ of the melter needle assembly or durin~ an
emer~e6cy condition, tha motor 262 rotates at its relatively high
rotational speed, i.e., 700 RPM and the clutch coupling 295 is
activated. Almost simultaneously, the pawl 318 is held in a
disengaged position from the ratchet 320 and the command shaft is
forced to rotate at a hi~h rotational speed. Conseq~ently, the
needle 30 is driven linearly at a relatively high rate of speed,
e.g., 6 feet per second. As should be understood, this quick motion
of the needle is necessary in order to prevent oxidation of the
molybdenum needle.
When the needle is in its full up position as indicated by
the needle position sensors, the piston ~9 may be forced upwardly by
the motive fluid that may be controllably admitted via conduit 47. As
A result, the boom subassembly 24 is forced to rise vertically to
such an extent that the needle 30 may clear the upper surface 21.
Conventional sensors may detect this condi.tion so that the boom
subassembly may be released by the solenoid operated pilot 67 and
rotated by the rotary actuator 58 to its retracted position. Where
ln the retracted position, shown in phantom in FIG. 2, the needle 30
may be serviced.
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