CA1045334A - Mold stopper - Google Patents

Abstract

MOLD STOPPER

Abstract of the Disclosure There is provided an improved stopper assembly to terminate the flow of molten metal into a mold cavity and to prevent reverse flow of molten metal after the mold has been filled. The stopper assembly includes a mounting spider secured within an opening of the mold cope and a stopper is frictionally held by the mounting spider and aligned so that a stopper washer is adapted to seat against the ingate of the mold.

Description

: : `

', ' MOLD STOPPER
: , . . , .:
,'i Th~s invention relates to the casting of metals . . . .
and more particul~rly to the casting of ferrous metal ~'' , , objects such as iron or steel railway car wheels. ;~
.: ': ' , ;
;,, It is known to cast railway car wheels by a , ,. .:j ,:
"" b~ttom pressure casting process. The casting method ''~,'1 comprises a system for forcing the molten metal up- ' ,~,, ' wardly through an ingete in the mold drag to fill "~
he mold cavity. A stopper is provided which is ', orced downwardly to shut off the flow of molten -,' -, 10 metal in the mold upon completion of the pressure '-;~: , ,; .-',1 pouring operation. In addition, the stopper assembly ' ' ,,'1 prevents the reverse flow of molten metal out of " ., "
the mold after the pressure has been shut off and ', the mold has been moved ~rom the ladle. Heretofore, ,','~
~ a stopper comprising a stopper plunger and a stopper ,',~
',''' washer ha~e been provided through an aperture in , ' i',''~'~ ' -~; the cope adapted to seat against the ingate in the ;' ~, ,',1 , drag and held open in any convenient manner such as, ,' '~
by a deformable wire or nail pass'ed through one of ;-.... . .. . .
a series o openings in the stopper pipe. In com~
mercial practice an electrical probe is provided in ,' ~' ' the mold riser to cut off the flow of molten metal ,~
',1 when the cavity of the mold is full. Thus it'has ' ''-.,, , ~ .
.. , _ ~, _, ,.
''` 'I
,-'.' I , .'' :
,... j ."`~ , ' ' ~, ;
, . '-, , 533~
i~ become desirable to electrlcally insulate the stopper rom the cope~ The stopper plunger was commonly held :; in position by a cardboard cylinder which served to frictionally hold the stopper open and additionally . served to electrically isolate the stopper from the ; 1 mold.
,~':,' '.
't., Difficulty was experienced in the assembly of ~ ... ,, ~- . i . ~. the stopper with the cope and urther by the in- :~
,~,.. .
;:. . stallation of th~ cardboard cylinder so that the .;,.. .
-.,. 10 method was cum~ersome, time consuming and costly.
, ,~. .
Accordingly, it is an object of the present .1 invention to provide an improved stopper for a ;' mold.
~ It is~a further object of the present invention .... 1 .
;.:,.;, ~:, to provide a stopper assembly which overcomes the . 1 above-mentioned difficulties.
I
~ urther features of this invention will herein-:. .-.! .
.~ after appear.
.. .. . .
.1 ~igure 1 is a cross-sectional ver~ical view .1 20 of a bottom pressure pouring system embodying the ~;, stopper assembly according to the invention; .
Figure 2 is a fragmentary cross-sectional view of the stopper assembly of Figure 1 illustrated to a larger scale; and ~` F~gure 3 is a plan cross-sectional ~iew o~ the .;. stopper assembly of Figure 2 .~aken along line 3-3 ~ ., i .. ~ thereof.
, . . .
,.. , . ~ . .
-, - 2 -... ~
".;, ,.

5i334 :~
. ~
~e~erring now to the drawings and particularly -:~` to Figure 1, there is illustrated a bottom pressure , pouring system a~cordin~ to the present invention . -and including a pressure tank generally designated as 10 comlected to a pneumatic supply line 11 .: adapted to deliver pneumatic pressure fluid such .,., ;
.~ as compressed air to act on molten metal 12 within `-a ladle 13. A cover 14 pneumatically closes the . -, pressure tank 10 and carries a pouring tube 15 having its lower end extending into the molten -. , . ~
, metal 12.
. A mold 20 is provided having a drag 21 and a cope 22. The drag 21 is provided with a downwardly :,...................................................................... . ~.
. opening ingate 24 adapted to align with the pouring .

.~, tube 15. The cope includes an opening 25 aligned :

;l with the ingate 24 for receiving a stopper assembly ,, .
28. Suitable riser means 29 may be provided as . desired. In the illustrated embodiment the cope ^~ and drag are ~ormed of graphite and are held assem- ;

~ 20 bled in any suitable manner such as with the clamp~

:', .
ng cylinders 30 to define a mold cavity 32. ~:

;,, It will be understood that in the bottom pressure .;~. pouring process the mold 20 and pressure tank 10 are :
;.i . ..
: assembled with the ingate 24 aligned with the pour- ~
., .
,l ing tube 15.of the pressure tank. The pressure tank ' ., 3 .,1 ,....... . . .

,. . .
" , , , , , , ._. ... . - n::

S33~
.~ , ~ 10 is p~essurized through the supply line 11 so that : . .
the molten metal 12 in the ladle 13 is forced up-. .
:;~ wardly through the pouring tube 15 and ingate 24 ,.; 1 ,.
' to fill the mold cavity 32. Suitable means such as , . , -~ ' an electrical probe (no~ shown) is provided for , , , .: " .
' sensing the need to terminate the flow of mol~en .:
i-~ metal when the mold cavity has been filled to the - ~.
.~ desired height. At this point,-it is necessary to ;~ close ~he ingate so as to terminate such flow of molten metal and ~urther so as to preven~ reverse ~; flow of molten metal from the mold cavity when the . .
mold 20 and pressure tank 10 are separated. A ~
.. . .
- plunger operating cylinder 31 is provided to oper-ate the stopper asse~bly 28.
In accordance with the present invention, there . ..... ; , is provided the improved stopper assembly 28 mounted ~n the cope 22. As herein illustrated the opening 25 in the cope 22 has an enlarged counterbore 25a ; at its upper end. The stopper assembly 28 includes a moun~ing spider 35 having a mounting ring 36 :,." ~ .
;,~ 8ecurely mounted in the counterbore 25a of the open-;1 ing 25. The moun~ing spider further includes a ~, ~eg~ented center spool 38 within the ring 36, having :, ~
' an inner bore 39 and defined by a fixed segment 38a ,~ 8ecured to the moun~ing ring by a rib 40. The cen~er .~
., , ."1 ;
~,~'. , .".., ;'. ..

.,; ; , , .. - . . .. . ... .. ... . . . ..

g~4533~
., ~pool 38 urther includcs a movable segment 38b ra-.~ dially movable relative to the fixed segment. A
... , . :.
~. rib 41 has a free inner end spaced from the movable !~' .,,' ~" .
~I segment 38b. In the illustrated embodiment the ' center spool 38 additionally includes an upper ring : portion 38c integrally formed with the fixed seg-:
: ment 38a. Suitable biasing means, here shown as :~
~ . a hairpin spring 45, urge the movable segment 38b :~ radially inwardly toward the fixed segment 38a.
,. . .
;`: 10 For this purpose, a pair o~ parallel grooves 42, . ~ .
~ ; 43 are provided in the outer walls of the fixed , . . . .
; ~egment 38a and 38b respectively for receiving the ~ legs 45a, 45b of the hairpin spring 45. The hairpin .. . .
:. spring 45 is held in place with its bight portion , . ........................................................................... .
45c against a projection 46 extending inwardly i from the mounting ring 36 and secured in any suit- ~:
~ ble manner such as by fasteners 47. A lower spool .. .. . . .
;:l, disk 48 is fixedly secured to the fixed segment . -;~ 38a of the center spool 38 in any suitable manner ... . . . ..
l 20 as by fasteners 49. Suitable electrical insulation :~
' 1 .
~.~ 37 between ~he mounting ring 36 and counterbore .~, , ~, .
~5a electrically isolate the stopper assembly from .~ the mold 20.
A stopper 50 is provided having a stopper plunger 51 rictionally held within the inner bore 39 and .. . .
.~ . ;.
,'' ' - S - ", , ~ .
, , : .

,.. .
.,. ~,.. . . . . . .

$33~
. . ~ . . .
,...~ ~
,. having an outer diame~er larger than the eontracted . ~ width of the bore 39 so as to bias the movable seg-.. ;~, .
.~ ment 38a outwardly against the return bias of the hai.rpin spring 45. A stopper washer 52~ 1 of gra-:.~ phite or other suitable material, is carried a~
~, the lower end of the stopper plunger within the .~ cavity 32-and adapted to seat agaînst the inner opening of the ingate 24.
It will be understood that the stopper 50 is -~ ~ 10 assembled in the center spool 38 prior to assembly : of the cope 22 and drag 21, and guided by the spool . .~, .
. ; ~isk 48 and upper ring portion 38c. Ins~allation ;~ of the stopper plunger within the center spool 38 q ~ _ ~ will spread the fixed segment 38a and movable seg-., ~:; .
.~, . ment 38b against the return bias of the spring 45.
,... ~ .
., The stopper 50 is frictionally held open, as il-:;j lustrated in Figure 1, by the friction created between the stopper plunger 51 with the fixed seg-ment 38a and movable segment 38b as a result of . . . ~ , , .
;, 20 the clamping pressure of the bissing spring 45.
~'5' . Upon filling of the mold cavity, the plunger opera- -,, ting cylinder 31 is actuated to drive the stopper plunger 51 downwardly until the stopper washer 52 . ~eats a~ainst the inner end of the ingate 24 thereby ",l 8topping further flow of ~olten metal into the mold ;;
.

, .. . . .
., .,'.': :
. .

,~ ,`.: , 4S33~ ~
` :. . .
avity 32 and preventing reverse flow o~ molten metal .. ~. out o~ tlle mold cavity 32 after the mold 20 and pressure tank 10 are separated~
~..................................... .

., .
,.~, . .
.L'' ' ~.~' ., ' . ',.
., ,.,- ' i ~''~ ' `:t~ .
~`,'`",' - . '`
i' :j .
. ,' ' `' ~ .
:,.,~ .. , '' . ' ~' ''',~,,.i . ' ., .
. .
!
, .~.i : -',: ~ .
.;'' ' . ' :,1.
, ,.. ~ , '.':: '. !
.. :''1 , ..
,'l . . :.

. . ~ - . .
., ~, .

. i, ~ ' ' ' ' ~,~`.i , ..
.,~,, ` , .`"j ` ~, ., I , .
`i'1 ;

; 'l `.1 7 ,. . .
" ~ .

` . .. .. . . - . .

Claims (5)

What Is Claimed Is:

1. A mold structure comprising, in combination, a mold assembly including a cope and a drag defining therebetween a cavity shaped for forming the desired molded article, said drag having an ingate in its bottom, said cope having an opening aligned above said ingate, and a stopper assembly mounted in said cope for stopping the filling of the mold cavity and for preventing reverse flow of metal out of the filled mold cavity, said stopper assembly in-cluding a mounting spider having a mounting ring securely mounted in said opening and a segmented center spool within said ring having an inner bore and defined by a fixed segment fixedly secured re-lative to said ring and a movable segment radially movable relative to said fixed segment, biasing means biasing said movable segment radially in-wardly, and a stopper including a stopper plunger having an outer diameter larger than the width of said bore so as to bias said movable segment out-wardly against the return bias of said biasing means 9 and a stopper washer carried at the lower end of said stopper plunger within said cavity adapted to seat against said ingate.

2. A mold structure as set forth in Claim 1 wherein the opening in said cope has an enlarged counterbore at its upper end receiving said mount-ing ring.

3. A mold structure as set forth in Claim 1 and including electrical insulation between said stopper assembly and said cope.

4. A mold structure as set forth in Claim 1 where in said biasing means is a spring.

5. A mold structure as set forth in Claim 1 wherein said cope and drag are formed of graphite and wherein said stopper washer is formed of gra-phite.