Note: Descriptions are shown in the official language in which they were submitted.
(Disclosure)
This invention relates to the art of induction
heating and more particularly to a ~ethod and apparatus for
inductively heating the axial end of an elongated workpiece.
The invention is particularly applicable for in-
ductively heating the button portion of a flanged axle
shaft and it will be described ~ith particular reference
thereto; however, it is appreciated ~hat ~he invention
has broader applications and may be used for heating the
a~ial end of various elongated workpieces~
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BACKGROUND OF THE INVENTION :
In the production of flanged axle shafts for automobiles,
the axle sha~t often includes a button portion which is a
cylindrical element having a generally flat outwardly facing
surface and spaced from the splined section of the axle
shafts by an undercut portion. This button is used for
supporting the shaft within the differential and must be
hardened and tempered for wear resistance and strength. In
the past, several systems have been used for performing this
process. Generally the buttons are heated separately by an
induction heating coil and then quench hardened. Thereafter,
tempering is accomplished by a ~urnace or a subsequent induction
heating operation wherein the hardened button is tempered at
a lower temperature than the hardening temperature. Since a ;
single workpiece was processed by prior systems, a substantial
amount of processing time was required and individual handling
was necessitated. The present invention relates to an improved
method and apparatus for accomplishing the hardening and -~
tempering of the button portion of an axle shaft, which method
and apparatus use induction heating and process several ¦
workpieces simultaneously and automatically.
STATEMENT OF THE INVENTION
- According to one broad aspect, the invention relates to
an apparatus for inducti~ely heating the axial, generally
cylindrical end of an elongated workpiece having a central
axis, said end terminating in a generally flat surface
generally perpendicular to said axis, said apparatus comprising:
means for mounting said workpiece for rotation about said axis;
means for rotating said workpiece about said axis; a generally
circular inductor matching said end; means for mounting said
inductor generally concentric with said ~xis; means for moving
said inductor ~long said axis from a remote position to a
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position contacting said surface; means for retracting said
inductor along said axis and away from said surface a pre-
selecte~ air gap distance; and means for energizing said
inductor when said inductor is in the retracted position and
while said workpiece is rotating.
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In accordance with another aspect of the in~ention,
two workpi~ces are processed by the above apparatus at the
same time and the required ~wo inductors are locked together
prior to being moved by the retracting means.
In accordance with another aspect of the in~ention there
is provided a connection between the movable inductor as
described above and a stationary power supply, which
connection includes a clampable, reciprocal joint.
The primary ob~ect of the present invention is the
provision of a method and apparatus for inductively heating
the axial ends of elong~ted workpieces, which method and
apparatus reduces the hanallng of the workpieces, provides
uniform result~, and increases the produ~tion rate.
Yet another ob~ect of the present invention is the
` provision of a method and apparatus for inductively heating the
axial ends of elongated workpieces, which method and
apparatus allows proces~ing of two or more elongated workpieces
simultaneously.
~ Still a further ob~ect of the present invention is the I
~ 20 provision of a method and apparatus as defined above which
can process more than one workpie~e and compensate for
variations in the axial lengths of the workpieces.
These and other ob~ectE and avdantages will become
; apparent from the following description taken together with
; the accompanying drawlngs in which:
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BRlEF DESCRIPTION OF DRAWINGS . .
FIGURE 1 is a pictorial view of the preferred
embodLment of the invention;
FIGURE 2 is an enlarged~ partial elevational view
showing one inductor assembly and its relationship with .
the power supply and workpieces; ~ -
FIGURE 2A is an enlarged cross-sectional view
: taken generally along line 2A-2A of FIGURE 2;
. FIGURE 3 is a cross-sectional view taken generally
along line 3-3 of FIGURE 2;
FIGURE 3A is an enlarged partial view showing
the inductor of the preferred embodiment; - : .
~ ~ ~ .
FIGURE 4 is a front elevational view taken generally . ~:
- along line 4-4 of FIGURE 3; .
FIGURE 5 is an enlarged cross-sectional view taken .
generally along line 5-5 of FIGURE 3;
FIGURE 6 is a pictorial view illustrating the
electrical connection used in the preferred embod~ment of
the present invention; .
. FIGURE 7 is a partial cross-sectional view of the
structure shown in FIGURE 6 illustrating one operating
condition of the clamping device;
FIGURE 7A is a view similar to FIGURE 7 iLlustrating : :
another operating condition of the clamping devioe;
FIGURES 8 and 8A are operational views t~ken
generally along line 8a-8a of FIGURE l;
. 25 FIGURE 9 is ~n enlarged pictorial view showing
the driving element of the rotating means and t~ken generally
~l~ng 9-9 of FIGURE l; :
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FI~URE 10 ls an end view showin~ a portion of the
workpiece to which the drive element of FIGURE 9 is received :~
. and taken generally along line 10-10 of FIGURE l;
FIGURE 11 is a schematic view of the driving :
arrangement used in the preferred embodiment of the invention
and is taken generally along line 11~11 of FIGURE l;
: FI~URES 12A-D are operating views showing various .
positions of the inductors with respect to the ends of the
workpieces during the operation of the apparatus shown in
. 10 FIGURE l; and,
~ FIGURE 13 is an enlarged partial view taken .
: generally along line 13-13 of FIGURE 1.
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GENERAL DESCRIPTION OF PREFERRED EMBODDMENT ~ ~
: . Referring now to the drawings wherein the showings ~ : :
are for the purpose of illustrating a preferred embod~ment
of the invention and not for the purpose of limiting same, : .
~ FIGURE 1 shows an apparatus A for inductively heating one
; axial end of the workpieces B. These workpieces, in
accordance with the preferred embodiment of the invention, ~ ,2'
are flanged axle ~hafts each including a body porti~n 10,
a 1ange 12 at one axial end, undercut porti~n 14, spli~ed
: segm2nt 16 and a button 20 at the opposi~e end from flange
12. The button 20 i8 defined by undercut portion 22 ~nd
~` includes a generally flat surface 24 facin~ axially from
- the workpiece B and generally perpendicular to the el~ngated
axis a of the workplece. Of course, a centering hole can be
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provided in flat surface 24. The ~enerally flat surface 24
may be sumewhat curved as long as it provides a surface
facing outwardly from the workpiece B. Th~ apparatus A
is used to harden and temper the button 20 which is formed
fr~m steel and is generally heated to 1700F and quench
hardened and then heated to approxLmately 500 and allowed
to cool. Other temperatures could be used in accordance
with the requirements of the steel to be hardened and
tempered. These temperatures are well known for each of
the various steels used in axl~ shafts and o~her similar
elongated workpieces. The button 20 is generally cylindrical
and has a known outer diameter. In accordance with the
preferred embodiment of the invention, the apparatus A -
includes a base plate 30 for supporting a portion of the
apparatus, a base plate 32 for supporting another p~rtion
of the apparatus, spaced heating stations 50, 52, h~ld-downs
54, 56 for these heated stations, a rotating mechanism 60,
heating units 70,72, a support frame and moving mechanism 80
for the heating units, a power supply illustrated as ~
transformer 90 and schemstically illustrated in FIGURE 6
as a generator, and power connectors 100 for connecting the
power supply to the heating uni~s. In the preferred embodiment
of the invention, two side-by-side heating units ~re illustrated;
however more than two stations could be used in practicing
the inventi~n. In addition, some aspects of the invention
could be used for a sin~le heating station device, even
though the invent~on is primarily adapted for use i~ heating
the axial end of t~o or more workpieces s~multaneously.
The base pl~tes 30, 32 used to support the other
ccmponents of ~pp~r~tus A' as best shown in FIGURE 1, are
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supported by a lower support struc~ure 110 which can take
a variety of structural forms. Base plate 30 lncludes an
extension 112 for supporting the rotating mechanism 60.
In a like manner, an extension 114 of base plate 32 is
used to support the power supply 90, shown in FIGURE 1
as a transformer, which transformer is powered by any
high frequency power supply in accordance with normal
induction heating practice.
CONVEYOR
Referring now co the conveyor 40, various types
of conveyors could be used; however, in accordance with the
- illustrated embodiment of the invention, conveyor 40 is a
walking beam type which includes two spaced, stationary beams
120,122. These beams include spaced workpiece receiving nests
124, 1269 respectively. Nests 126 are formed by a forward
element 128 engaging the cylindrical portion of the workpiece
; and a plate 129 having semicircular recesses 129a engaging
extension 129b of workpieces B. A pair of walking beams 130,
only one of which is shown, includes nests 132. Of course, a
nest is provided on each of the two walklng beams to engage
the cylindrical portion 10 of workpiece B, in accord~nce with I
normal walking beam construction. The ne~ 132 include
V-shaped notches 134, as shown in FIGURE 1. The operation
of the walking beams 130 progress workpiece B from the loading
~ 25 end 140 of apparatus A, to the heating stati~ns 50,52 and then
- to the unloading end 142. The action of a walking beam is `~
j~ well known in the conveying and induction heating ~rts.
Beams 130 move upwardly to remove workpieces B fro~ the nests
1249 126. The beams sre then moved toward the unloadlng
positi~n 142 a distance to progress the workpiece~ a distance
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corresp~nding t~ the space between adjacent nests 124, 126.
Beams 130 are then moved downwardly to deposit the workpieces
on the next stationary nests. This action is repeated twice
to remove the two heated workpieces from the heatin8 stations
50, 52 and deposit them at the unloading position or end
142 of apparatus A. At the same time, two unprocessed
workpieces are moved to the heating stations 50, 52. The
processed workpieces are removed fr~m apparatus A by any
appropriate mechanism. In a like manner, any appropriate
device can be used for deposlting two unprocessed workpieces
at loading end 140 after walking beam conveyor 40 has
` cycled twice. ¦
WORKPIECE SUPPORTING STRUCTURE -
Referring now to the heating stations 50, 52, the
; 15 workpiece supporting nests and related structure at the
heating stations ~or supporting the workpieces are illustrated
in FIGURES 1, 3, 8, 8A and 13. As best shown in FIGURXS 1,
3 and 8, journals 150, 152 rotatably receive rollers 154, 156,
respectively. These rollers engage the lower side of the
2~ workpieces to support the workpieces at the heating stations.
At the heating stations, the flanged end of the workpiece
are supported on V-shaped notch 160, best shown in FIGURE 13,
which notches generally correspond to the structure of
nests 126, on the stakionary beam 122 with sidewalls 160a,
160b having a ~eight to clesr transverse rolls 162, 164
supported on ~ournal blocks 166, 168. These rolls rotate ~-
about an axis generally perpendicular to the axis of
workpieces B. The rolls are u~ed to engage flange 12 durlng
the rot~tion of the workpiece B in the heating ~nd quenching
cycle, in a m~nner ~o be described later. Hold Downs
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54~ 56 are posltioned 1a~o4v9 6a~9et of rollers 154, 156 at .
each of the heating stations 50? 52. The hold downs are
best shown in FIGURES 1, 3 and 8. Since the hold downs
are substantially the same, hold down 54 will be explained
. 5 in detail, and this description will apply equally to hold .
down 56. The slide 170~ shown in FIGURE 1, includes a
rearward extension, not shown, slidably received between
two, spaced, fixed rails 172 which, in turn, are secured
to a fixed plate 174~ This plate is secured to stand 176. :
A cylinder 177 reciprocates slide 170, which carries a roll :
178 rotatably mounted in journal 179 secured to slide 170.
As shown in FIGURE 8, the rod of cylinder 177 moves hold
down roll 178 into engagement with the undercut portion ¦
: 174 above a pair of rolls 154, 156. This completes the
15. locating and holding function of workpieces B at the axial
end adjacent to the button 20 at the heating stations.
ROTATING MECHANISM
Referring now to the workpiece rotating mechanism
. 60, best shown ln FIGURES 1 and 11, ~his mechanism is used
to engage and rotate the workpieces supported at the heating
;~ stations 50, 52. A variety of structural arrangements could ;
be used for this mechanism; however, in accordance with the
illustrated embodlment, a housing lBO is supported on stand
181 secured to the extension 112 of basP plate 30. Reciprocally
mounted plungers 182, 184 move in tubes 185, only one of which
is shvwn.CYlinder8 186, 188 supported on stands 18~a, 188a,
respectively, selectively move plungers 182, 184 within the
support tubes 185. Heads 190, 192 bes~ shown in FIGURE 1~ :
are carried by the plungers 182, 184 at opposite ends from
c~nders 186, 188. These heads engage the flanged ends of
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workpieces B to rotate the workpieces about their longltudinal
axes a. A selectively energized electric motor 200 drives
a gear reducer 202 having an output sprocket 204, best shown
in FIGURE 11. This sprocket drives chaln 206 connected
with sprockets 208, 210 which reciprocally receive plungers
182, 1841 respectively. Keys 212, 214 allow reciprocation of
plungers 182, 184 within sprockets 208, 210 without loslng
a driving connection between the sprockets and the plungers.
In this manner9 the sprockets remain generally fixed in an
axial direction and the plun~ers 182, 184 are selectively
moved therein by cylinders 186, 188 to engage the workpiece
by heads 190,192. As shown in FIGURE 9, head 192 includes
an elongated protrusion 220 which matches a recess 222
on flange 12 of the workpiece~ as best shown in FIGURES
1 and 10. This provides a driving connection between the
heads 190, 192 and the workpieces B. Forward movement of
heads 190, 192 forces protrusions 220 into recesses 222 for
rotating the workpieces. This forward movement of the heads
190, 192 forces flange 12 into engagement with rolls 162,
164. This provides a positioning of the workpieces B in an
axial direction. Since there is some manufacturing tolerances,
buttons 0 at the opposite ends of workpieces B in the two
heating stations may not be in exact alignment. Apparatus A,
in accordance with an aspect of the invention, provides an
arTangement to c~mpensate for any manufacturing tolerances
~nd thus different axlal positions of buttons 20 of the two
simultaneously heated workpieces B. The axial spacing o~ the
workpieces due to m~nufacturing tolerances or other rea~ons,
i~ schematicslly illustr~ted in FIGURES 12A-D ~hich will be
used ~l~bsequently to explain the compensating characteri8tics
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of the present invention.
HEATING UNITS
Referring now to the heating units 70, 72, only unit
70 wlll be described in detail and this descriptlon will apply
equally to the other unit 72. Of course, more than two
~ide-by-side heating units could be used for simultaneously
heating any number of buttons 20 on workpieces B. In the
pre~erred embodiment, only two such heating units are
employed. These heating units are best shown in FIGURES 1,
2, 3, and 4. Both heating units are supported on a c~mmon
base plate 230 which is moved in unison in a manner to be
described later. This plate is supported on cross beams
-~ 232, 234, shown in FIGURE 3. Two or more vertic~l support
brackets 236 are used to reinforce the support structure
for heating units 70, 72. This support structure is secured
to a lower plate 238 attached to the upper portion of the
support frame and moving mechanism 80 which will be de~cribed
later. Referrin~ now to the individual he~ting unit 70, as
~hown in FIGURE 3, this unit includes a support block 240
which i~ somewhat hollowed to provide recesses for bear~ngs
242, 244 and to provide a central rereæs 246 for a purpose
to be e~plained later. Stands 250, 252 are supported nn the
upper portion of block 240 to define a central rece~ or
opening 254. These stands and the support block 240 are
~25 ~ecured onto plate 230 by a plurality of vertically e~tending
bolts 256 which e~tend through the stand 176 supporting
~he hold do~n 54 at ~tatio~ 50. A rod-like element 260 i8
; reciprocally mounted within bearings 242, 244, 88 ~hown ln
FIGURE 3. One end of the rod-like element includes a support
head 262 for mounting an insulatad c~rrier 264. The carrier
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includes a center bore 266 for directing a quenchlng liquid ;
from an inlet 268 to an outlet 270. This liquid is used
for quenching the button 20 after it has been heated to a
hardness temperature by a generally circular inductor 280,
best shown in FIW RE 3A. This inductor includes a gap 282,
best shown in FIGURES 2 and 4, to fonm the inductor 280 in
an electrical 1ODP configuration as is standard in the induction
heating art. The forward facing portion of inductor 280 is
contoured to provide a conical extension 284 having an outwardly ;
facing surface 286 generally matching button 20. This surface
286 has an outer diameter generally the same as the known
~ outer diameter of button 20; however, it can be sli~htly
different in diameter. Of course, the surface 286 is ring
shaped as shown in FIGU~E 4 to accommodate the outlet 270 in
the quenching fluid passage thrDugh carrier 264. Inductor
280 includes a standard internal passage 288 to allow
circulation of the coolant liquid through the loop forming
the inductor at least during the heating cycle to prevent
overheating of the inductor in accordance with normal ~-
induction heating practice. Inductor 280 a~ the gap 282
is connected with input leads 290, 292 which are generally
flat plates or bars ghaped ~s shown best in FIGURE 3. These
bars are separated by insulation m~terial 294 and ~enerally . -;~
extend coterminuous with the rod~like element 260 frcm the ~;
2S carrier 264 to beyond the outer end of the rod-like element, ~ ;
as shown in FIGURE 3. These two leads with the divlding
insulator 294 maintain the electrical loop of inductor 280
and extend rearwardly as a somewhat single unlt to provide
an input element for the inductor. An insulated bolt 296
~ecures the c~rrier and leads 290, 292 as a unlt at the
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forward end of rod-like element 260. Coolant lines 300, 302
on the opposite sides of plates or bars 290., 292 provide
coolant paths to and from inductor 280. One of these lines
has an appropri~te coolant input and the other has a coolant
output. They are both connected with the internal passage
288 for circulatin~ coolant along bars 290, 292 and around
inductor 280, at least during the heating cycle. The coolant
inlets to lines 300, 302 are not lllustrated since they may
be provided by taps at various locations along these lines
and do not orm a part of the present invention. The rear
end of rod-like element 260 is provided a rear support 310
for connecting the leads 290, 292 with the rear end of
element 260. This rear support of leads 290, 292 could take
a variety of structural configurations; however, in accordance
: 15 - with ~he illustrated embod~ment of the invention, as is best
shown in FIGURES 3 and 5, rear support 310 includes a block
312 having a central recess 314. This recess receives th~ :
two spaced plates or bars 290, 292 electrically connected
with inductor 280. Insulation pl~tes 316, 318, as shown in
FIGURE 5, and insulated bolts 320,322 secure leads 290, 292
. fixedly with respect to block 312. At lower end of block
312, there is pro~ided a bore 324 in which a reduced portion
of rod-like element 260 extends. This reduced portion i~
locked from rotation by a key 326 extending within a keyw~y
of block 312. Nut 328 is threadably received upon the
terminal end of element 260 and holds the element fixedly - ~:
with respect to block 312 b~ using the shoulder defined
by the reduced portlon of el~ment 260. As 80 far de~cr~bed,
element 260 can reciprocate ~ith~n block 240. This ~
csuse like reciprocstion of plute~ 290, 292 secured above
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element 260 and extend through opening 254. Key 326 extends
into a slot 330 of an end cap 332 secured to the right end
of block 240. This cap also retains reciprocating journal
or bearing 244. A rear boot 334 extends between cap 332 and
the rear portion of block 312, as best shown in FIGURE 3.
A cap 340 similar to cap 332 is provided at the opposite end
of block 320 to hold bearing or j ournal 242 in place within
the bloclc. The front boot 342 extends from support head
262 to cap 340. The biasing spring 350 biases rod-like
element 260 to the left, as shown in FIGURE 3. This spring
extends between support head 262 and an outwardly ~acing
shoulder of cap 340. This spring continues to bias the
element 260 and all structures secured thereto to the l~ft
toward the workpiece,B. An appropriate stop 332 is secured ~,
, onto the. rear end of element 260 between cap 332 and block
312. This stop engages the rearwardly facing surface of
cap 332 to limit the amount of forward m,ovement of element
260'by the biasing spr~g 350. The amount of backward movement ' ~ -
against the action of spring 350 is limited basically by the -'
spring 3~0 and the spacing between head 262 and cap 340.
~1 , As 80 far explained, rod-like element 260 can be
forced rearwsrdly against spring 350. The forward movement
of the element is limited' by stop 352. The purpose of these ,~
:~ functions will be explained later.
.i 25 Referring now to the center recess 242 within block
,:
240, as shown in FIGURE 3, this recess holds a double ended .;.. ~ h~
spring clip 360 h~ving t~o end8 362, best shwm in FIGURE 2A.
A clamping rod 364 is controlled by l:3ylinder 366, as shown in
FIGURE 2. When the clamp~ng rod is retracted, two spaced ends ~:~
362-are pulled together to ~lamp spring clip 360 around element
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260. This locks the element with respect to block 240.
Reciprocation of elemen~ ~60 within block 240 is thus
prevented. Consequently, at any reciprocated position of
element 260, retraction of cylinder 366 locks the element
with respect to block 240. This type of locking arrangement
is known for reciprocating members and is only one of many
which could be used. When rod 364 is extended by cylinder
366, ends 362 are shifted apart to release element 260
for reciprocation with respect to block 240. By providing
this arrangement, the block 240 may be reciprocated by
mechanism 80, to be described later, until surface 286 of
inductor 280 contacts surface 24 of button 20. Continued
forward movement toward the button by block 240 causes
compression of spring 350. When th~ desired amount of
! 15 forward movement of block 240 is effected, cylinder 366
actuates spring clip 360 to lock element 260 with respect
to block 240. Thereafter, movement of the block away from
the workpiece draws the inductor away from button 20 a
distance determined by the rearward retraction of block 240. -
At this time, element 260 moves with the block because of
the locking action of clip 360. This function will be
explained later in connectio~ with the operation of
apparatus A as shown in FIGURES 12A-D.
SUPPORT FRAME AND MOVING MECHANISM ~:
The support fr~me ~nd move mechanism 80 bes~ shown in .:
FIGURES 3 and 4 is u~ed to 8upport induction heating units 70
72 ~nd to mcve the units by wæy of l~wer plate 238 toward
- ~nd sway from workpieces B supported on apparatus A. A
varietr of mechsnisms could be used for accomplishing the
proper movement in accord~nce with the pre8ent invention;
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however, in accordance with the illustrated embodiment,
a common plate 37~ supports lower plate 238 and is reciprocally
mounted on spaced rails 372, 374. Keepers 376, 378 hold
the plates 360 onto the rails and allow reciprocal movement
toward and away from the workpieces as shown in FIGURE 3.
Secured below plate 370 is a trunnion 380 which is moved by
cylinder 382 through a rod 384. Cylinder 382 is supported
onto a reciprocal plate 386 movable within notches on spaced
stands 387, 388, as best shown in FIGURE 4. These stands
are stationary and are mounted on base plate 32. In operation
of the moving mechanism 80 as so far described, plate 386
ls held stationary by an arrangement to be described later.
When rod 384 is extended from cylinder 382 trunnion 380
forces plate 370 orward. This moves both heating units
70, 72 toward their respective buttons 20. As each of the ~ ;
inductors 280 engage surface 24 of the respective workpieces,
forward movement of the inductor is halted. This stops
forward movement of element 260. Since there has been no
clamping of clip 360, block 240 continues to move base plate
370. After both of the inductors have engaged the buttons,
and the two springs 350 have béen compressed, forward
movement of trunnion 380 is stopped by halting the forward
movement of rod 384. In this position, each of the two
inductors 380 are in engagement with the buttons 20 irrespective
of slight axial misalignment of the buttons. Cylinder 366
of each heating unit 50, 52 is then energized to lock element
260 with respect to block 240. It is ln this position that
the additional function of mechanism 80 comes into play.
This additlonal function is the retraction functlon to
retract the two blocks 240 away from workpieces B ~ distanoe
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corresponding to the deslred air gap; which is generally
in the range of 0.40 inches and is represented by the
dimension b in FIGURES 3 and 12D. This retracting mechanism
39~ is best shown in FIGURE 3 and includes a first rack
392 carried on the fo~ard end of plate 386. The second
I rack 394 is reciprocally mounted within a block 396 secured
; to base plate 32. A pinion 398 engaging racks 392, 394 is
journalled on a shaft 400 supported on spaced bars 402, 404
secured to base plate 32. A cylinder 410 also supported
on base plate 32 reciprocates rack 394 between fixed stop .
411 and adjustable stop 412.
In the operation of cylinder 382, cylinder 410 is
in the position shown in FIGURE 3 which holds pinion 394
against stop 411. This holds pinion 392 in a fixed position
determined by pinion 396. Consequently, plate 386 is ~
stationary during operation of cylinder 382. After the ~ :
cylinder has moved both inductors into engagement with
buttons 20 of the workpieces, spring clips 360 are contracted . : ~ .
to lock element 26~ with respect to blocks 240. At this time,
cylinder 410 is energized to push pinion 394 forward as sh~wn
in FIGURE 3. Forward movement ls the distance b detenmined
by the ad~ustable stop 412. This forward movement of pinion
394 causes rearward movement of pinion 392. This rearward
movement shifts plate 396 to the right as shown in FI&URE 3 ..
a distance corresponding to the movement of pinlon 394. ! ~:
Trunnion 380 is pulled to the rlght, which retracts the locked
element 260 from buttons 20 a distance detenmined by the
adjustable stop 412. This distance corresponds to the ' -
desired air gap for the heating operation. After the retracticn
operation, power supply 90 energizes inductors 280 with a high
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energy alternating current. In the preferred embodiment,
the heating operation is accomplished at approximately 50
kilowatts o power. After the desired time necessary to
heat buttons 20 to approximately 1750F, the heating
operation is terminated. Thereaf~er, quenching fluid is
forced through the inlets 268 and from outlets 270 for
the purpose of quenching the heated buttons. After the
quenching operation, inductors 280 are again energized with
a low power, such as approxi~ately 12-15 kilowatts. This
low power is continued until the quench hardened buttons
20 are heated to a temperature of approxLmately 500F.
Thereafter, the low power heating cycle is discontinued to
allow tempering of the buttons 20. ~ `
- SEQUENCE OF OPERATION ~ ;~
The sequence of operation is schematically illustrated
in FIGURES 12A-D. In these figures, two side-by-side ~ -
workpieces B', B" are illustrated as being axially offset
to provide ~xially offset buttons 20. Referring now to
FIGURE 12A, the start of the apparatus A is illustrated.
Since lockingclips 360 are rele~sed, elements 260 of heating
units 70, 72 are released to be moved forw&rd by biasing
springs 350. Thus, the inductors 280', 280" are appro~imately
aligned with respect to e~ch other. Thereafter, cylinder 382
- ætarts forward movement of the heatin~ units and, thus,
inductors 280', 280" toward the workpieces B~, B". As the
movement of the inductor~ toward the workpieces continues,
inductor 280" engages the button of workpie~e B" which extends
outwardly farther than the button of the other workpiece.
This i8 ~hown in FIGURE 12B. At this ~me, c~ntinued operation
of cylinder 382 compre3ses ~pring 350 assoc~ated with inductor
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2~0" and ~l~ws continued movement of inductor 280' toward
the workpiPce B'. When the button of the second workpiece
is engaged as shown in FIGURE 12C~ sprin~ 350 of the other
heating unit is compressed. Thus, forward movement of the
inductors 28~', 280" is stopped even though cylinder 382
continues to move forward. After a predetermined amount
of movement determined by the stroke o~ cylinder 382, the
cylinder is stopped. Thereafter, clips 360 of the two
heating units are actuated by cylinders 366 to clamp
elemen~s 260 with respect to blocks 240. Thereafter, cylinder
410 is energized to shift rack 394 against adjustable
stop 412. This moves inductors 280', 280" away fr~m buttons
20 of workpieces B', B" a distance corresponding to the
desired air gap b. This ~s shown in FI~URE 12D. Thus,
the desired air gap is prov~ded between the buttons and
the inductors, irrespective of slight axial misal~gnment
of the adjacent buttons of workpieces B', B". When the
inductors are in the position shown in FIGURE 12D, the high
powered heating, liquid quenching, and low powered tempering
cycles are performed in accordance with normal induction
- heating practice. During the two heating operations, and
~- the quenching operation hold downs 54, 56 support the
~- workpieces at the button ends and rotating mechanism 60
rotates the workpLeces. This assures unifonm processing
of the buttons during both heating and quenching of the
buttons. In accord~nce with the illustrated embodlment~ ¦
the hold d~wns 54, 56 are not shifted down by energizing
cylinders 177 until the positi~n shown in FIGURE 12D is
- assumed. The hold downs ~re carried by blocks 240 and m~ve !~
with the blocks during the establishment of the air gap
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as shown in FIGURES 12~-D. After the tempering operation,
cylinders 177 are retracted first. Thereafter, cylinders
382, 410 are retracted to return the inductors to the
position shown in FIGURE 12A. At this time, cylinders
186 are retracted to disengage the heads 190, 192 fram
the flanges 12 of the workpieces. At this time, conveyor
40 removes the processed workpieces and inserts unprocessed
workpieces in the heating station for subsequent processing
in accordance with the above description. This procedure
is continued so that subsequent workpieces are processed
. .
automatically by apparatus A.
POWER CONNECTOR ~-
Referring now to the power connector 100, as shown
in FIGURES 6, 7 and 7A, plates or bars 290, 292 are
electrically conductive leads connected to the opposite sides
of the gap formed in inductors 280. These leads are fonmed
` from a conductive material, such as copper, in accordance
with induction heating practice. These two leads or plates
are secured together at the forward end of c~rrier 264
and at the rear support 310, best shown in FIGURES 3 and 5.
The rear support physically clamps the leads 290, 292 together
80 that they, in essence, form a rearwardly extending single
element which has two spaced conductive portions on opposite
sides thereof. This element is movable with the heating units
70,72. Since the power supply 90 is fi~edly secured ~o
extension 114 of base plate 32, a movable electrical c~nnection
; is required between output leads 92, 94 of the power supply
and the clamped element includlng leads 290, 292. Power
`- connecelon 100 provides ~his ralative movement withOu
requlrlng flexible leads. In n~cordance wieh this aspect
,
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of the invention, the power connector includes means for
allowing slidable reciprocation of the plates 290, 292
with respect to the power supply and then provides for
clamping the leads in a manner to establish electrical
connection between the respective leads and the output leads
92, 94 of power supply 90. A variety of particular structures
could be used in accomplishing this function; however, in
accordance with the preferred embodiment of the invention,
leads or plates 290, 292 include enlarged rear portlo~s
420, 422 each having outwardly extending rails 424, 426.
These rails are slidably received within grooves 430, 432
of the power connector 100. Output bar or lead 9i has an
arm 440, best shown in FIGURE 6, which terminates in an- :
outwardly facing surface 442. In a like manner, ou'~put
lead or bar 94 has an outwardly extending arm 444 terminating :~
at generally flat surface 446. An intermediate bloek 450
is positioned between the lead 290 of heating unit 72 &~d
bar 292 of the spaced heating unit 70. In this manner,
block 450 has the groove 432 for one bar 292 of heating
unit 70, as shown at the left in FIGURE 6 9 and the groove
430 for bar 290 of heating unit 72 positioned at the rlght
of FIGURE 6 and as shown in FIGURES 2 and 7. Clamping plate~
460, 462 are provided at opposite sides of connector lO0.
~ Plate 460 includes a groove 430 for bar 290 of unit 70.
: 25 Clamping plate 262 has a groove 432 for bar 292 of unit 72.
In this manner, the barg connected with inductors 280 are
slidably received between a clamping plate, 460 or 462,
snd ~ntermediate block 450 when preSsure is relieved from
the two clamplng plates. Cyl~nder~ 464, 466 have rods
which control the position of clsmpin~ plates 460 3 462 and
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are positioned on stands 470, 472, respectively. An
insulation sheet 474 and insulated bolts 476 support the
cylinders 464, 466 in insulated fashion on base p~ te 32.
Appropriate means are provided for holding intermediate ;
blocks 450 in the desired position. During the adjustment
and movement of inductors 280, cylinders 464, 466 are
slightly retracted to remove pressure from the enlarged
portions 420, 422 of leads or bars 490, 492. Thus, these
leads or bars can reciprocate with respect to the intermediate
block and clamping plates 460 462. The amount of movement
may be different because of the axial spacing of separate
buttons 20 of the workpieces. After inductors 280 of ~-
the two heating units are in the desired position as sh-own
in FIGURE 12D, apparatus A is in proper condition for
lS heating buttons 20. At this time, cylinders 464, 466 force
plates 460, 462 against surfaces 442, 446, respecti~ely.
The transverse width of enlarged portions 4~0, 422 are
~uch that this clamping action against surfsces 442, 446
clamps the enlarged portions between the clamping plates
460, 462 and the intermed~ te block 450. Consequently,
electrical circuit is established as shown by the arrows
in FIGURE 6 to energize both inductors 80 in parallel.
After the heatlng operation has been performed, cylinders ~;464, 466 are retracted which releases the enlarged portions
420~ 422 ~nd allows relative movement of the bars 290, 292
with respect to ~he rema~ning structure illu~trated in
FIGURE 6. In this manner, ad~ustable leads are not required
between the pcwer supply 90 and the-lead~ connected with
lnductors 280 of the two he~ting units 70, 72.
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