Device to park a dummy bar downstream from the extraction and straightener group

Abstract

 Device to park the dummy bar (11) that can be used in continuous casting machines with a casting line (17) having rollers (18) which stretches between the ingot mould (16) and the substantially horizontal outlet and comprises an extraction and straightening group (12) located at said outlet, said device including in combination:

- a swinging supporting structure (21) to pakthe dummy bar (11), said structure (21) being sustained revolvably at its upper side downstream from said extraction and straightening group (12) and being able to rotate between a raised position of rest and a lowered working position,

- oscillator means (24) which can carry out rotation of said supporting structure (21) between its position of rest and working position, and

- means (25) which can pull and clamp the dummy bar (11) on said supporting structure (21) and are anchored to the same said structure (21), whereby possible known means are also envisaged for controlling and coordinating the actuation of said oscillator means (24) and said means (25) which pull and clamp the dummy bar (11).

Description

[0001] This invention concerns a parking device for the dummy bar normally used to withdraw the continuous billet in conti- .nuous casting plants.

[0002] To be more exact, the invention concerns a structure .that swings between two positions, whereby the first position is used to park the dummy bar during its phase of rest, where- .as the second position is employed to support and guide said. .dummy bar during the phase of initial insertion thereof and . .also during the phase of starting the continuous billet (here- .inafter called "billet").

[0003] In the art of continuous casting the molten metal is .conveyed in a wheeled ladle or by a crane to an ingot mould .having an open bottom and suitable shape and located above .the casting line.

[0004] Said ingot mould receives the molten metal from said .ladle through a pre-heated tundish and discharges said metal. .downwards through its open bottom in a partly solidified con- .tinuous flow of a pre-set section; said flow becomes gradually .solidified on the casting line with the help of suitable cool- .ing means located in the first part of said casting line.

[0005] It is necessary to close the open bottom of the ingot. .mould temporarily before beginning the casting so as to pre-. .vent a disorderly flow of the metal.

[0006] The open bottom of the ingot mould is closed by means. .of a dummy bar, which is inserted by a group of entraining . .rollers into the open bottom of the ingot mould, and any gap. created between the dummy bar and the open bottom is sealed_'. .with suitable refractory material.

[0007] The first part of the metal poured into the ingot mould .thus closed is left to solidify partially so as to become uni- .ted to the head of the dummy bar.

[0008] Following on the filling of the ingot mould and the .oscillation thereof to hinder the formation of a crust of me- .tal on its inner walls, the entraining rollers are actuated . .and arrange to pull the dummy bar and withdraw the billet con- .nected to the end of said bar.

[0009] The dummy bar is detached from the billet thereafter . .and is parked in a suitable position near the extraction group .and discharge line, along which the cast metal goes on travel- .ling for the rolling processes which follow thereafter.

[0010] Said dummy bar, now having a new head, is taken once again from its parking device at the beginning of the next .casting and the foregoing procedure to start the billet is .followed once more.

[0011] Known dummy bars are substantially of three kinds:

.rigid bow-shaped dummy bars, semi-rigid bow-shaped dummy bars consisting of a number of articulated segments and flexible chain-type dummy bars.

[0012] The known systems to park rigid dummy bars or semi- .rigid dummy bars in segments require a fixed supporting structure which is shaped like a bow, lies on the vertical plane of .the casting line, stretches upwards from the extraction group .and ends at a point having a height not less than the height. .of the ingot mould.

[0013] Patents US 3,930,533 (Rokop), US 3,433,287 (Greenberger). and US 3,344,844 (Reinfeld and others), which describe systems for parking dummy bars of this type, reveal some problems relating to the bulky construction, heavy weight and unsatisfactory lay-out of said fixed bow-shaped structures.

[0014] Patent US 3,682,233 (Rokop and others) claims a system . .to park flexible dummy bars which consists of a substantially upright fixed structure with a horizontal tract, the structure .being located above the extraction group and casting line, whereby a secondary entraining group is lodged in the horizontal tract so as to move the dummy bar within said bearing structure.

[0015] Notwithstanding the advantages offered by this system by. way of a lesser bulk than in said known systems, yet this system still takes up a great deal of space and is only fit for flexible dummy bars.

[0016] Indeed, the structure proposed in this patent stretches. vertically above the ingot mould and takes up much useful space both near the extraction group and near the upper part of . the casting plant.

[0017] One problem common to the foregoing known parking systems lies in the fact that the new head of the dummy bar can be fitted only near the extraction group.

[0018] It is the purpose of our invention to embody a device to. park dummy bars which swings between a raised position of rest and a lower working position and which is able to take up leas space than known parking systems and to be lighter and cheaper to make.

[0019] One advantage lies in the fact that the invention enable.s a new head to be fitted to the dummy bar in its raised position far from the extraction group during the phase of rest. This leads to a great saving of time and therefore to high output.

[0020] Another advantage is the free space created near the extraction group and discharge line during casting; this space. can be employed for other more useful purposes.

[0021] our invention is therefore embodied with a device to park dummy barswhich can be used in continuous casting mach-. ines with a casting line on rollers stretching between the ingot mould and the substantially horizontal outlet and comprising an extraction and straightening group located at said outlet,said device being characterized by including in working . combination: .

- a swinging supporting structure to park the dummy bar,whereby said structure is revolvably supported in its upper part downstream from said extraction group and can rotate between a raised position of rest and a lowered working position, .

- oscillator means able to rotate said supporting structure between its position of rest and working position, and .

- means able to pull and clamp the dummy bar on said supporting structure, said means being anchored to said structure,. whereby means are also envisaged for controlling and coordinating the actuation of said oscillator means and said means . which pull and clamp the dummy bar, in relation to the overall working of the casting machine

[0022] In a preferential embodiment of the invention said sup-. porting structure consists of a cradle structure with a sub-. stantially bow-shaped profile and with a U-shaped section, . whereby said cradle structure comprises a tubular element through which the rotation shaft passes and which is solidly. fixed to the upper part of the two vertical sides of said structure, and whereby the cradle structure includes one or . .more integral levers stretching outwards and radially in re-. .lation to said tubular element and cooperating at their end . .with said oscillator means anchored to the fixed structure .of the machine on which said cradle structure pivots, and .where'by said cradle structure in its turn bears means to pull .and clamp the dummy bar which are able to effect any displace- .ments of the dummy bar and the clamping thereof during the .phase of rest.

[0023] The pulling of the dummy bar along the casting line and. the loading thereof on the supporting cradle structure are .carried out advantageously by the group which extracts the .continuous billet.

[0024] We shall describe hereinafter a preferential embodiment. of our invention as a non-restrictive example and shall refer to the attached tables, wherein:

Fig.1 gives a side view of the continuous casting machine . with the cradle structure to park the dummy bar according to the invention;

Fig.2 gives a view in the direction of the arrow C of Fig.I and shows only said cradle structure in its horizontal position where said structure is shown in Fig.I with. lines of dashes in its position of rest;

Fig.3 shows the tail of the dummy bar.

[0025] In the figures the same parts or parts having the same . functions bear the same reference numbers.

[0026] In Figs.I and 2, the device 10 which parks the dummy bar 11 is located downstream from and above the group 12 that extracts and straightens the true billet or continuous billet . 13 in a continuous casting machine consisting of a ladle 14, tundish 15 and an ingot mould 16 having an open bottom and . positioned on the casting line 17 equipped with rollers 18 . .and with a curved guide 118, said line 17 having in its first .tract a cooling chamber 19, whereby there could be an oscil-. lating group which acts on said ingot mould 16.

[0027] Downstream from the group 12 extracting and straightening the billet is positioned the roller discharge table 20 on .which the billet runs after the dummy bar has been detached . .with known unfastening means generically indicated with II2..

[0028] In the example shown said group that unfastens the dummy .bar II is part of the extraction and straightening group 12 and acts so that the head of the dummy bar anchored to the .actual billet 13, when unfastened, is separated from said dummy bar II, which goes without its head onto the parking device .10 and lets the actual billet run along the roller discharge. table 20 for the processing phases thereafter.

[0029] The parking device 10, shown in Figs.I and 2 and the pur- .pose of our invention, consists of a swinging supporting structure 21 having a cradle-shaped structure 121 with a substant- .ially bow-shaped bottom equipped with a plurality of idler rollers 22 and with two upright sides 221 connected together at. .their end with crosswise elements (not shown here), whereby . .a crosswise tubular element 321 is envisaged and is anchored. .at its ends to said upright sides 221 in their upper part. Thus the cradle structure 121 has a substantially U-shaped . .section..

[0030] Said tubular element 321 has at its ends two levers 421. .which stretch out radially in relation to said tubular element 321 so as to form a fork together with said tubular element 321.

[0031] Said levers 421 are preferably tilted in relation to the. .upper edge of said upright sides 221.

[0032] The two sides 221, tubular element 321 and two levers . .421 form the unitary cradle structure I2I. Said cradle structure 121 is arranged revolvably on the bearing structure 22 . of the machine at a point above the discharge line 20 and just downstream from the extraction and straightening group 12.

[0033] Said anchorage point consists of a pivot 122 on which the tubular element 321 of the cradle 121 revolves. Figs.I and 2 show a preferential but not restrictive embodiment of the oscillator means 24 which can actuate the rotation of the cradle structure 21 between a horizontal raised position of rest shown with lines of dashes and another sloped working position in which the end B of the cradle structure lies in correspond- .ence with the outlet of the extraction and straightening group .12.

[0034] In our example said oscillator means 24 consist of a hy- .draulic or pneumatic jack 124 anchored at one end to the bear- _.ing structure of the machine 22 by a suitable support 222, _.while the stem 224 of said jack 124 pivots at 322 on a crosswise shaft 425 solidly fixed at its ends to the free end of .each of said levers 421, so that said stem 224 can actuate . the rotation of the cradle structure I2I around said pivot .122.

[0035] According to the invention said cradle structure 121 also comprises means 25 suitable for pulling and clamping the dummy bar II on said cradle structure 121.

[0036] Said pulling and clamping means 25 only start working when the dummy bar is out of the reach of the extraction and straightening group 12, and serve to pull the dummy bar II and hinder the return thereof, after its head has been detached, to said extraction and straightening group 12.

[0037] In our example said pulling and clamping means 25 com- .prise a jack 125 pivoting at one end at 225 on the cradle .structure I2I; said jack 125 cooperates with an arm 325 swing- .ing at 326 on a shaft 426 anchored at its ends to two supports .525 which are an integral part of the cradle structure 121.

[0038] Said cooperation between the swinging arm 325 and jack . 125 takes place through the articulation of the stem 251 at . .the point 252 located between the free end 327 of the arm 325 .and the point of rotation 326 of said arm 325.

[0039] The free end 327 of said arm 325 is a hook-wise end and. .can lodge itself in an upright notch 211 located lengthwise in the tail 411 of the dummy bar II and can cooperate with a. .pin 311 located crosswise within said notch 2II, as shown in. Fig. 3.

[0040] Said pulling means 25 are required to provide a thrust . .only in an upwards direction and are inactive when the dummy .bar has to be inserted in the extraction and straightening . group, to which the dummy bar II descends, taking with it the .free end 327 of the swinging arm 325, from which it is automa- .tically detached when said arm 325 reaches the stop at the .lower end of its run.

[0041] It is best for us to emphasise that the clamping action. of the means 25 is only necessary when the cradle structure. 121 is in its sloping position since in the position of rest .the dummy bar stays still within said structure, where the .fitting of its head III is prepared in a raised working sta-. .tion near which the end B of the cradle structure I2I halts..

[0042] When the dummy bar II is to be inserted during the ready- ing of the machine at the beginning of casting, the cradle . .structure I2I, taking with it the dummy bar II complete with. .a removable head III, is driven by the oscillator means 24 so .as to take up its working position.

[0043] Said bar II stays attached to said cradle structure 121, owing to the clamping action of the means 25.

[0044] . When the working position is reached, the jack 125 is disactivated and enables the arm 325 to revolve clockwise _.under the action of the weight of the dummy bar, which inserts .itself in the extraction and straightening group 12 and enters upon its field of work.

[0045] The group 19 pulls the dummy bar II along the casting .line 17 until its head III is inserted into the bottom of the .ingot mould 16.

[0046] When the first casting phase ends, the dummy bar II, of. which the tail has stayed during said phase between the en- . training rollers 212 of the extraction and straightening group 12, is withdrawn and thrust along the cradle-wise parking structure 121, which is lying in its working position.

[0047] When the head III of the dummy bar reaches said extraction rollers 212, the pin 311 provided in the tail 411 of the. dummy bar II lies near the bottom dead centre of the hook-like end 327 of the swinging arm 325, said end 327 being now in a. .raised and retracted position.

[0048] The jack 125 now starts working, rotates said arm 325 anti-clockwise and forces said arm to hook itself onto the .pin 3II of the dummy bar II and to pull said dummy bar II upwards while its head III is still anchored to the billet 13.

[0049] When said head III reaches the means 112 that unfasten .the head, the dummy bar II is freed in a known way and conti- .nues its path along the cradle structure I2I until the swing- .ing arm 325 reaches its top dead centre, where said arm 325 . is clamped by the jack 125 and at the same time hinders the return of the dummy bar II downwards.

[0050] The actual billet 13, instead, goes on moving along the .roller discharge table 20.

[0051] The oscillator means 24 now start working and, by the .actuation of the two-way jack 124, revolve the cradle struct- .ure 121 and therewith the dummy bar into the raised parking . .position or position. of rest, where a new head III is fitted .and made ready for the next casting.

[0052] We have described herein a preferential embodiment of the .invention, but further variants are possible.

[0053] The shape and constructional features of the swinging cradle structure 121 can be varied, and other kinds of actua- .tion means can be envisaged for performing the action of the. .oscillator means 24 and pulling and clamping means 25, said other kinds of actuation means being able to cooperate with flexible dummy bars of the types having articulated segments, .or chains, the whole being possible for a person skilled in . .this field without departing thereby from the scope of the in- .ventive idea of this invention.

Claims

I. Device to park the dummy bar (II) that can be used in continuous casting machines with a casting line (17) which employs rollers (18), stretches between the ingot mould (16). and the substantially horizontal outlet and comprises an ex-. .traction and straightening group (12) located at said outlet, said device being characterized by including in combination .and mutual cooperation and coordination:

a swinging supporting structure (21) for parking the dummy. bar (II), said structure (21) being revolvably sustained at its upper side downstream from said extraction and straightening group (12) and being able to rotate between a raised. position of rest and a lowered working position,

oscillator means (24) which can carry out rotation of said. supporting structure (21) between its position of rest and. working position, and

- means (25) which can pull and clamp the dummy bar (II) on said supporting structure (21) and are anchored to the same said structure (21), .
.whereby possible known means are also envisaged for control-. .ling and coordinating the actuation of said oscillator means. .(24) and said means (25) which pull and clamp the dummy bar . (II).

2. Device as in Claim I, characterized by the fact that. .said swinging supporting structure (21) consists of a cradle. .structure (I2I) which has a substantially bow-shaped profile. .and U-shaped section and pivots at its upper side on the fix- .ed bearing structure (22) of the casting machine.

3. Device as in Claim 2, characterized by the fact that. .said cradle structure (I2I) has two upright sides (221) which are connected together in their upper part by a tubular ele-. .ment (321) and at their lower end by a bottom consisting of . .rollers (22).

. 4. Device as in Claim 3, characterized by the fact that. .said tubular element (321) pivots on a pin (122) sustained .crosswise by the bearing structure (22) of the machine.

5. Device as in Claim I or in Claim 2 or 3, characterized .by the fact that said cradle structure (I2I) has one or more. .actuation levers (42I) stretching away from the axis of rotat- .ion of said structure (121) and anchored at one end to the outer surface of said tubular element (321).

6. Device as in Claim I or in one or another of the .Claims thereafter up to Claim 5 inclusive, characterized by . .the fact that said actuation levers (421) are tilted in relat- .ion to the upper edges of said upright sides (221) of said .cradle structure (121).

7. Device as in Claim I and in one or another of the .Claims thereafter, characterized by the fact that said oscil- .lator means (24) consist of a jack (124) pivoted at one end . .on the bearing structure (22) of the machine and having the .free end of its stem (224) pivoting at (322) on a crosswise shaft (425) anchored at its ends to the free ends of said actuation levers (421).

8. Device as in Claim I and in one or another of the .Claims thereafter, characterized by the fact that said pulling and clamping means (25) comprise a jack (I25) pivoted at one .end at (225) on the cradle structure (I2I), whereby the stem. .(251) of said jack (I25) is pivoted at an intermediate point. .on a swinging arm (325) pivoted at one end (326) on a crosswise shaft (426) anchored at its ends to two upright supports .(525) solidly fixed to said cradle structure (I2I), and whereby the free end (327) of said swinging arm (325) follows an . arc tangential to the lengthwise axis of said cradle struct-. ure (21).

9. Device as in the Claims hereinbefore, characterized . .by the fact that said free end (327) of the swinging arm (325) .comprises, in its edge opposite the outer end (A) of the cra- .dle structure (I2I), a hook-like profile which can cooperate. .with a pin (311) positioned crosswise within a lengthwise .groove (211) machined in the tail (411) of the dummy bar (II).

Drawing