US3593776A

US3593776A - Starter bar having a frangible coupling

Info

Publication number: US3593776A
Application number: US771822A
Authority: US
Inventors: Calvin C Williamson
Original assignee: Soule Steel Co
Current assignee: Soule Steel Co
Priority date: 1968-10-30
Filing date: 1968-10-30
Publication date: 1971-07-20
Anticipated expiration: 1988-07-20

Abstract

This is a detachable starter bar coupling in which a head member is detachably connected to one end of a continuous casting starter bar. The connection is made by means of a bolt having a reduced section near its midpoint so that the application of a preselected amount of force on the coupling will cause the bolt to break and the head to detach from the starter bar. The head is provided with a projecting bolt at one end thereof which is inserted in the continuous casting mold in order to be embedded within the cast strand as it solidifies.

Description

United States Patent [72} Inventor Calvin C. Williamson Costa Mesa, Calif. 21 1 Appl. No. 771,822 [22] Filed Oct. 30, 1968 [45] Patented July 20, 1971 [73] Assignee Soule Steel Company San Francisco, Calif.

[54] STARTER BAR HAVING-A FRANGIBLE COUPLING 4 Claims, 5 Drawing Figs.

[52] US. Cl 164/274, 64/28, 85/61, 164/282 [51] Int. Cl 822d 11/08 [50] Field of Search 164/274, 282, 283; 64/28; 85/61; 285/2, 3

[56] References Cited UNITED STATES PATENTS 490,313 1/1893 Schlickeysen 64/28 2,085,074 6/1937 Boyles 85/61 UX Primary Examiner-R. Spencer Annear Attorney-Townsend and Townsend ABSTRACT: This is a detachable starter bar coupling in which a head member is detachably connected to one end of a continuous casting starter bar. The connection is made by means of a bolt having a reduced section near its midpoint so that the application of a preselected amount of force on the coupling will cause the bolt to break and the head to detach from the starter bar. The head is provided with a projecting bolt at one end thereof which is inserted in the continuous casting mold in order to be embedded within the cast strand as it solidifies.

STARTER BAR HAVING A FRANGIBLE COUPLING This invention relates to continuous casting apparatus and, more particularly. to a detachable coupling head for continuous casting starter bars. While the continuous casting art can be considered to date back to the time of Bessemer, continuous casting of steel on a commercial basis is of comparatively recent development. The invention of the principle of casting a continuous strand by means of a curved, reciprocating mold by Schneckenburger (US. Pat. No. 2,947,075) revolutionized the industry. Schneckenburger describes the use of either a curved, solid starter bar, or a starter bar made up of comparatively short, bent parts. As is well known, the starter bar is inserted into the bottom of the flow through mold in order to seal the bottom of the mold and permit the molten steel or other metal to begin to solidify prior to the formation of the continuous cast strand. If an articulated starter bar is utilized, that is a bar having a number of detachable sections, it is comparatively easy to detach the starter bar sections individually as the bar moves downward from the mold leaving only a corn paratively short piece firmly attached to the strand as the strand is fed from the mold.

In the usual continuous casting apparatus utilizing a curved mold, straightener rolls are located at the point at which the curved strand is travelling in a horizontal direction. The straightener rolls straighten the curved strand to permit the strand to move horizontally along a table so that individual billets may be cut from the strand. In those cases in which a solid, curved starter bar is utilized, the problem of disconnecting the starter bar from the leading edge of the cast strand is more difficult. Sections of the starter bar cannot be removed since the bar would in such a case be destroyed. Thus, some quick disconnect coupling is necessary to permit the curved, solid bar to be disconnected from the cast strand.

The present invention was designed to permit a solid curved starter bar to be readilyattached to the continuously cast strand and as readily detached in order to permit the starter bar to be removed from the machine and reutilized for subsequent casting runs.

This is accomplished in the present invention by utilizing a detachable coupling in which a coupling member has a projection thereon which may be cast into the strand, the coupling member being fastened to the starter bar by means of a severable fastener. This fastenerwill break upon the application of a preselected amount of force, which will cause relative movement of the starter bar and the cast strand. This relative movement may cause the severable fastener to break in shear or in tension. The specific choice will depend upon the construction of the continuous casting machine and the means used for changing the direction of the cast strand.

In the present invention a severable fastener is utilized so that the coupling member will be positively fastened to the starter bar until a preselected amount of force on the order of 2,000 to 3,000 pounds is applied. Thus, there will be no opportunity for accidents to occur should the coupling head accidentally become detached from the starter bar. It should also be noted that when the coupling head is fastened to the starter bar the bar may be moved into position to seal the bottom of the mold and the casting cycle begun without the necessity for any further adjustments or steps until the fastener is severed upon separation of the starter bar from the cast strand.

In continuous casting, m'ost molds are reciprocated in order to reduce the sticking of the cast strand skin to the mold walls. The reciprocation of the mold and the occasional sticking of the strand causes jerky movement of the strand. As a result it has been found that a positive connection of the coupling member to the starter bar is required to preclude the accidental disconnection of the starter bar from the strand. This positive connection is made in the present invention by means of a severable fastener which positively connects the coupling member to the starter bar until sufficient force is applied adjacent the coupling member to break the fastener.

IN Tl IE DRAWING FIG. I is an elevation showing the detachable starter bar coupling connected to the' cast stran-d as the strand begins to leave the casting mold;

FIG. 2 is a detail of the straightener rolls showing the separation of the starter bar from the coupling head attached to the cast strand;

FIG. 3 is an enlarged plan view of the coupling head attached to one end of the starter bar;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3; and

FIG. 5 is a detail of the severable bolt utilized to hold the coupling head to the end of the starter bar.

Referring now more particularly to the drawing in which the same reference characters refer to corresponding parts in each of the several views, the general arrangement of the starter bar, coupling head and casting apparatus is shown in FIG. I. The starter bar 10 is made up of a number of comparatively short, curved sections 12 joined together by means of pins 14. The section 16 of the starter bar closest to the casting is formed at the end thereof in any conventional manner to interlock with the coupling head 18. A hole 20 is bored through the endof the starter bar 16 and the coupling head 18 with counterbores 22 at either end of the holes so that a bolt 24 may be used to fasten the head and bar together. The head 26 and the nut 28 fit within the counterbores 22 so that they are fully recessed within the surfaces of the starter bar and coupling head. The coupling bolt 24 has a notched portion 30 at approximately its midsection the depth of the notch preselected so that the bolt will break upon the application'of between 2,000 and 3,000 pounds of axial load.

The coupling head has a drilled and tapped hole 32 therein to accommodate a headed-bolt 34 which serves to anchor the head 18 to the cast strand. I

At the commencement of the cast the starter bar 10 with the coupling head 18 bolted to it by means of the severable bolt 24 is moved into position along the roller apron indicated in FIG. I by the plurality of rollers 36. The coupling head and the starter bar have dimensions approximately equal to those of the inside of the flow-through mold 38. These will also be dimensions of the cast strand 40. The head 35 of anchor I 34 extends into the inside of mold 38 and after the molten I steel has been poured into the mold the head 35 will become embedded within the leading tip 42 of the cast strand 40. When the casting process commences the starter bar 10 is slowly withdrawn along the roller apron drawing the cast strand 40 with it. The cast strand continues to be withdrawn until the tip 42 of the cast strand reaches the straightener rolls 44 which are located at a point at which the cast strand is approximately tangent to a horizontal path. The straightener rolls 44 when in the raised position as is shown in FIG. 1 will permit the starter bar to continue on the generally arcuate path to a storage facility 46 within which the bar may be held until the beginning of the next casting cycle.

When the starter bar reaches the position at which the end section 16 of the starter bar is located as shown in FIG. 2, just past the straightener rolls, the straightener rolls are moved by powerful hydraulic cylinders or other means (not separately shown) downward from the position shown by the broken lines in FIG. 2 to the position at which they are shown in FIG. 2. The application of the 'force of approximately 2,000 to 3,000 pounds will force the tip 42 of the cast strand, together with the coupling head 18 which is firmly attached to the tip, downward thus breaking the bolt 24' which has previously fastened the coupling head 18 and the end section 16 firmly together. After the coupling head 18 has been detached from the starter bar by the breaking of bolt 24, the cast strand is straightened by continued action of the straightener rolls 44.

The strand 40 passes horizontally along the horizontal roller table 48 to the cutoff machine where the individual billets are severed from the strand 40. The coupling head 18 may be removed from tip 42 of the cast strand by unscrewing the head from bolt 34. A replacement bolt 34 may then be inserted into the head and the head fastened to the end of the starter bar 16 by means ofa new severable bolt 24.

The coupling bolt 24 may, as an alternative to being notched, have a hold drilled through its shank or may have its cross section reduced in any suitable manner so that a preselected amount of force will cause the bolt to break at the reduced section.

lclaim:

1. In a starter bar device having a detachable head for a continuous casting starter bar, said head having anchor means at one end thereof for insertion into the continuous casting mold to permit solidification of thecast metal of the strand about said anchor means, the other end of the head formed to engage cooperating portions of an end of the starter bar, the improvement comprising: a frangible connector transversely through said other end of said head for positively holding the head attached to the cooperating end of the starter bar until the application of a substantial preselected amount of force to break the connector and separate the head from the starter bar end.

2. The detachable head of claim 1 wherein the starter bar end has a bore therethrough for accepting a frangiblebolt and said bore has a counterbored recess for receiving the bolt end so that the bolt is below the starter bar surface. g I

3. The detachable head of claim 1 wherein the head has a bore therethrough for accepting a frangible bolt and said bore has a counterbored recess for receiving the bolt end so that the bolt is below the detachable head surface.

4. The detachable head of claim 1 wherein the frangible connector comprises a bolt having a reduced cross section, the area of said cross section being sufficient to fasten the head to the starter bar during initial casting operation but permitting separation of the head from the starter barby breakage of the bolt at the reduced cross section upon the application of a substantial preselected amount of force.

Claims

1. In a starter bar device having a detachable head for a continuous casting starter bar, said head having anchor means at one end thereof for insertion into the continuous casting mold to permit solidification of the cast metal of the strand about said anchor means, the other end of the head formed to engage cooperating portions of an end of the starter bar, the improvement comprising: a frangible connector transversely through said other end of said head for positively holding the head attached to the cooperating end of the starter bar until the application of a substantial preselected amount of force to break the connector and separate the head from the starter bar end.

2. The detachable head of claim 1 wherein the starter bar end has a bore therethrough for accepting a frangible bolt and said bore has a counterbored recess for receiving the bolt end so that the bolt is below the starter bar surface.

4. The detachable head of claim 1 wherein the frangible connector comprises a bolt having a reduced cross section, the area of said cross section being sufficient to fasten the head to the starter bar during initial casting operation but permitting separation of the head from the starter bar by breakage of the bolt at the reduced cross section upon the application of a substantial preselected amount of force.