US3457757A - Billet return mechanism - Google Patents

Description

July 29, 1969 E. N..MATHIEU ETAL 3,457,757

' BILLET RETURN MECHANISM Filed Feb. 16, 1967 5 Sheets-Sheet 1 i Y INVENTORS A guy; )4 Edmond N. Mcnhieu BY William R. Wynn fmrll,

ATTORNEYS July 29, 19s9 E. N. MATHIEU ETAL BILLET RETURN MECHANISM Filed Feb. 16, 1967 5 Sheets-Sheet '2 INVENTORS Edmond N. Maihieu By William R.Wynn

ATTORNEYS E. N. MATHIEU ETAL 3,457,757

' July 29, 1969 BILLET RETURN MECHANISM 5 Sheets-Sheet 5 Filed Feb. 16. 1967 INVENTORS Edmond N Mothieu BY William R. Wynn M flM ATTORNEYS E. N. MATHIEU ET AL 3,457,757

July 29, 1969 BILLET RETURN MECHANISM 5 Sheets-Sheet 4- Filed Feb. 16. 1967 INVENTORS Edmond N. Mofhieu y William R. Wynn ATTORNEYS y 9, 1969 E. N. MATHIEU mL 3,451,151

I BILLET RETURN MECHANISM 7 Filed Feb. 16. 1967 5 Sheets-Sheet 5 INVENTORS Edmond N. Muthieu William R. Wynn ATTORNEYS United States Patent BILLET RETURN MECHANISM Edmond N. Mathieu, Fitchburg, and William R. Wynn,

Holden, Mass, assignors to Morgan Construction Company, Worcester, Mass., a corporation of Massachusetts Filed Feb. 16, 1967, Ser. No. 616,512

Int. Cl. B211) 37/00; B21d 55/00; C21d 1/06 U.S. Cl. 72-203 7 Claims ABSTRACT OF THE DISCLOSURE A movable guide trough employed in a rod rolling mill between the furnace pull-out rolls and the first roll stand which supports the leading end of the billet during normal mill operation. Upon the occurrence of a cobble or the like, the billet is sheared upstream of the first roll stand, the pull-out rolls are reversed, and the guide trough is pivoted to an upper position where the guide trough floor is drawn into the downstream nip of the pullout rolls to drive the sheared billet entirely into the furnace.

This furnace relates to a mechanism for use in a continuous rolling mill whereby in the event of a cobble or the completion of a test run of a portion of a billet through the mill, that part of the billet which has not reached the first roll stand will be returned to the reheating furnace.

More particularly, this invention relates to improved means for returning the unrolled portion of the billet to the reheating furnace following a cobble or trial length. The mechanism includes means for promptly shearing the billet at a point between the pinch rolls and the first roll stand so that that part of the billet which has not entered the first stand can be saved.

In the continuous rod rolling process, billets (generally from 1% to 4 inches square and approximately 40 feet in length) are charged into the reheating furnace, pushed laterally across the furnace hearth and, after reaching the end of the hearth and attaining the proper temperature, are pushed longitudinally out the furnace door toward the first roll stand. A set of pinch rolls is located adjacent the furnace door to frictionally engage and pull each billet from the furnace with the leading end directed toward the first set of reducing rolls. A guide trough leads from the pinch rolls to the first roll stand to guide and support the advancing end of the billet. Between the guide trough and the first roll stand is a shear which is actuated when a cobble occurs or a trial length has been completed.

As the leading end of the billet issues from each roll stand along the mill line, its speed increases because its diameter is progressively reduced. The hot metal is relatively stiff as it passes through the roughing stands and the intermediate stands but becomes progressively more flexible as it moves through the finishing stands. On occasion, the leading end of the rod, moving at high speed in the finishing stands, may miss a pass opening causing an immediate and continuously growing jumble of hot rod known as a cobble.

The cobble must be cleared before the rod rolling operation can be re-established. conventionally, when the operator observes a cobble, he actuates a flying shear located upstream of the cobble which continuously shears the advancing partially rolled rod into short lengths. These lengths fall into a cobble box located beneath the flying shear. An up and down shear is also actuated to shear the billet upstream of the first roll stand. The pinch rolls are then reversed to return the unrolled part of the billet to the furnace through the discharge door to maintain its temperature during the cobble clearing operation. The pinch rolls cannot return the entire billet completely into the furnace, however, without assistance. It has been customary to insert a wooden scantling into the downstream bite of the reversed pinch rolls as soon as the returning billet has cleared the pinch rolls on the upstream side. The scantling is driven against the sheared end of the billet to push the billet entirely back into the furnace. This was strictly a manual operation which was slow, clumsy,

dangerous and required the undesirable presence of wooden scantlings in the work area.

This invention comprises a novel and useful mechanism for returning the unrolled part of the billet to the furnace after being sheared between the pinch rolls and the first roll stand and constitutes a considerable improvement over the previous above-described conventional practice. In brief, this invention comprises a relatively thick floor in the guide trough which has a horizontal upper surface for supporting the travel of the leading end of the billet and a substantially vertical face at the furnace end. The guide trough floor is carried in an underlying cradle and is slidably mounted for longitudinal movement with respect to the cradle. Means are provided to pivotally engage the cradle and to selectively move it between (a) a lower or normal position in which the upper floor surface is horizontally aligned With the pinch roll nip, and (b) an upper or billet return position in which the floor is thrust into the downstream bite of the pinch roll nip. Thus, upon the occurrence of a cobble or upon the completion of a test run where only a portion of the billet is used, the billet is sheared at a point between the pinch rolls and the first roll stand, and the pinch rolls are reversed to drive the billet toward the furnace exit door. After the billet has left the pinch rolls, the cradle and trough floor are moved from the lower to the upper position thereby thrusting the floor into the pinch roll bite, and the floor is driven by the reversed pinch rolls against the sheared end of the billet to return the billet entirely into the furnace.

It is an object of this invention to completely automate and mechanize the billet return operation.

It is another object of this invention to eliminate the use of wooden scantlings.

It is another object of this invention to make the billet return operation faster, safer and consistently efficient.

Other objects and advantages of this invention will become apparent from a study of the accompanying drawings and descriptive matter in which is illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a side elevation of a preferred embodiment of the invention showing the pinch rolls pulling the billet out of the furnace;

FIG. 2 is a detailed plan view of the invention shown in FIG. 1, with the upper pinch roll and its support carriage removed;

FIG. 3 is a view in section taken along line 3-3 of FIG. 2 showing the guide trough cradle and floor in its lower position;

FIG. 4 is a view in section, similar to FIG. 3, showing the guide trough cradle in its upper position with the guide trough floor engaged in the bite of the pinch rolls; and

FIG. 5 is a schematic diagram of a portion of a typical continuous rolling mill showing the location of the invention.

To more particularly describe the invention, reference should first be made to FIG. 5 which illustrates schematically that portion of a typical continuous rolling mill with which this invention isconcerned. A charging conveyor 10 delivers a succession of longitudinally spaced billets 12, which have previously been weighed and separated, into the reheating furnace 14 through furnace entry door 16. The floor or hearth of the furnace 14 slopes downwardly toward the discharge end of the furnace. After each billet 12 is charged into the furnace, it is pushed sideways against the previously charged billets by furnace crosspusher 20. The billets are brought up to the required temperature as they move slowly sideways across the furnace hearth and are sequentially discharged through exit door 18 by furnace push-out 22.

As the leading end of each billet 12 emerges through furnace exit door 18, it enters the nip of a set of horizontal pinch rolls 24. Pinch rolls 24 engage the leading end of the billet and begin to pull the billet out of the furnace 14. A guide trough 26 is positioned between pinch rolls 24 and the first reducing roll stand 28 and supports the leading end of the billet in its travel from pinch rolls 24 to the first roll stand 28 passing shear 34 en route. In the rolling mill layout shown in FIG. 5, eighteen horizontal (H) and vertical (V) roll stands are provided in an alternating arrangement.

FIG. also shows the drum shear 30 and its associated crop pit 32 into which short lengths of sheared rod are continuously deposited in the event of a downstream cobble. Shear 34 of the up and down cut type is actuated to shear the billet after a cobble or production of a test piece of rod just prior to reversing the pinch rolls 24 to return the unused part of the billet into the furnace.

Referring now to FIGS. 1-4, it will be seen that pinch rolls 24 include lower roll 36 which is journaled in a stationary housing 38. Roll 36 is turned by drive shaft 42 which is coupled to conventional drive means (not shown) for selective driving of lower roll 36 in either direction. Upper pinch roll 40 is journaled in a swinging housing 41. Roll 40 is not powered and is free to revolve in either direction. Upper pinch roll 40 is adapted to pivot about pivot axle 44 on spaced carrying arms 46 which are provided with journal collars 48 at their swinging ends. The gripping effect of pinch rolls 36 and 40 is produced by the weight of roll 40 assisted by an actuator (not shown). The rolls may be provided with serrated roll surfaces to increase their effectiveness.

The guide trough 26 is located between pinch roll stand 24 and the first reducing roll stand 28. It includes a stationary pair of converging centering guides 50 which are mounted on underlying supports 51. These centering guides prevent sidewise misalignment of the leading end of the billet as it issues from the pinch rolls.

A second converging pair of centering guides 52 is located downstream from the first stationary pair 50. The second pair of centering guides may be fixed to underlying supports or may, as shown in the drawings, be fixed to the trough cradle 54 by side plates 56.

The trough cradle 54 rests in its lower or normal position upon upstream support 51 and downstream support 58. Cradle 54 is generally U-shaped and carries therein a trough floor 60 which is mounted for longitudinal sliding movement with respect to the cradle. Trough floor 60 has a horizontal upper surface 62 for supporting the leading end of the billet 12 as it moves from the pinch rolls 24 to the first reducing roll stand 28 (as shown in FIG. 3). Trough floor 60 also has a substantially vertical face 64 adjacent the pinch rolls which is adapted to squarely meet and drive the remainder of billet 12 back into the furnace (as shown in FIG. 4).

Trough cradle 54 is pivotally carried by swinging pivot arms 66 and 68. Upstream pivot arm 66 is linked to the cradle by transverse shaft 70 and to the machine base by laterally spaced shafts 72. Downstream pivot arm 6-8 is linked to the cradle by transverse shaft 74 and to the machine base by shaft 76 which has substantial length. An underlying ram 78 is pivoted to the machine base at 80 and is connected to lever 82 at 84. The operation of ram 78, acting through lever 82, shaft 76 and arm 68, drives cradle 54, with its floor 60, from the lower or normal position shown in FIG. 3 to the upper or billet return position shown in FIG. 4. Lever 82 is rigidly keyed to shaft 76 which in turn is rigidly keyed to arm 68.

In operation, as furnace push-out mechanism 22 pushes a billet out furnace exit door 18, the leading end of the billet 12 enters the nip of the pinch rolls 24 and is engaged thereby as shown in FIG. 1. At this stage, the guide trough 26 is in its shown lower position of FIGS. 1, 2 and 3. The leading end of billet 12 then moves over the horizontal upper surface 62 of floor 60, being laterally restrained by centering guides 50 and 52 until it enters the first reducing roll stand 28. The leading end of the billet then progressively picks up speed as it passes through the roughing and intermediate roll stands and enters the finishing stands. It is in these latter stands that a cobble is most likely to occur because of the speed, diameter and flexibility of the rod that has by then developed.

In the event that a cobble should occur in stands 9H to 18V, the drum shear 30 is actuated by the operator causing the continuously issuing rod from stand 8H to fall into crop box 32 in short lengths. The up and down cut shear 34 is also actuated, substantially simultaneously, to sever the billet 12 at a point between the guide trough and the first roll stand. The pinch rolls 24 are then reversed. Thus, only that part of the billet beyond shear 34 continues on into the first roll stand. That portion of the billet on the furnace side of shear 34 is driven by the pinch rolls back into the furnace to the full extent possible until the billet leaves the pinch rolls.

The swinging housing assembly 41 is then raised to swing the upper pinch roll 40 clear. Then ram 78 is actuated to pivot the guide trough cradle 54 from its lower position shown in FIG. 3 to the upper position shown in FIG. 4. During this movement, face 64 of guide trough floor 60 engages the cut end of billet 12 forcing it a short additional distance into the furnace. Then the upper pinch roll 40 is lowered into the position shown in FIG. 4 with trough floor 60 firmly engaged in the nip of the pinch rolls and floor face 64 in contact with the leading end of billet 12. The pinch rolls are then rotated in reverse direction to cause floor 60 to be driven upstream against the billet end until the billet is returned completely into furnace 14. It will be understood that floor 60 is long enough to span the distance from the pinch rolls to the furnace interior.

The pinch rolls 24 can then be reversed to drive floor 60 away from the furnace to the position shown in FIG. 4. Then, the upper pinch roll 40 is swung clear and the trough cradle 54 is returned by ram 78 to its normal position of FIG. 3.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that this invention is not limited to the details of the construction specifically described or illustrated, but is to be defined by the appended claims in light of the scope and spirit of the disclosed invention.

We claim:

1. In a rolling mill having a billet furnace, means for sequentially pushing each heated billet out the furnace door, pinch rolls located adjacent the furnace door for receiving the leading end of each billet and for driving it toward the first reducing roll stand, a guide trough located between the pinch rolls and the first roll stand for supporting and centering the leading end of each billet, and a shear located between the guide trough and the first roll stand; an improved billet return mechanism for returning the unrolled portion of a billet entirely into the furnace in the event of a cobble or the like comprising:

(a) a floor in the guide trough having a horizontal upper billet support surface and a substantially vertical upstream face,

(b) a floor cradle in the guide trough in which said trough floor is slidably mounted for longitudinal movement, and

(c) means engaging said floor cradle for Selectively moving said trough floor and cradle from a lower position in which said billet support surface of said floor is substantially horizontally aligned with the pinch roll nip to an upper position in which said upstream face of said floor is thrust into the nip of the pinch rolls, whereby, upon the occurrence of a cobble or the like in the rolling mill, the unrolled portion of the billet is sheared between the pinch rolls and the first roll stand, the pinch rolls are reversed to drive the billet toward the furnace, the trough floor and cradle are pivoted from the lower to the upper position and the floor is driven upstream by the pinch rolls with the floor face bearing against the sheared billet end to return the billet entirely into the furnace.

2. The mechanism of claim 1 wherein said means for selectively moving said trough fioor and cradle comprises at least one pivot arm having said cradle afiixed thereto at its swinging end, and drive means for rotating said pivot arm.

3. The mechanism of claim 1 wherein said means for selectively moving said trough floor and cradle comprises a pair of pivot arms mounted on spaced apart parallel transverse shafts, said arms pivotally carrying said cradle at their swinging ends, and drive means for rotating said pivot arms.

4. The mechanism of claim 3 wherein said drive means comprises a ram pivoted at one end to one of said pivot arms.

5. The mechanism of claim 1 capable for use in the alternate events of a cobble, a test piece run or a furnace clean-out.

6. In a rolling mill having a billet furnace, means for sequentially pushing each heated billet out the furnace door, pinch rolls located adjacent the furnace door for receiving the leading end of each billet and for driving it toward the first reducing roll stand, a shear located between the pinch rolls and the first roll stand and a guide trough located between the pinch rolls and the shear, said guide trough including a billet return mechanism having a floor in the guide trough having a horizontal upper billet support surface and a substantially vertical upstream face, a floor cradle in the guide trough in which said trough floor is slidably mounted for longitudinal movement, and means engaging said floor cradle for selectively moving said trough floor and cradle from a lower position to an upper position, the method of returning the unrolled portion of a billet completely into the furnace in the event of a cobble or the like comprising the following steps:

(a) shear the billet between the pinch rolls and the first roll reducing stand;

(b) reverse the pinch rolls to drive the sheared billet upstream toward the furnace;

(c) pivot the guide trough fioor and its underlying cradle from the lower position in which the billet support surface of the floor is substantially horizontally aligned with the pinch roll nip to the upper position in which the upstream face of the floor is thrust into the nip of the pinch rolls; and

(d) operate the pinch rolls to drive the nip-engaged guide trough floor upstream with the floor face bear ing against the sheared billet end to return the billet entirely into the furnace.

7. The method of claim 6 further characterized by the following steps:

(e) reverse the pinch rolls to drive the nip-engaged guide trough floor downstream out of the nip of the pinch rolls; and

(f) pivot the guide trough floor and its underlying cradle from the upper position in which the upstream face of the floor is in the nip of the pinch rolls to the lower position in which the billet support surface of the floor is substantially horizontally aligned with the pinch roll nip.

References Cited UNITED STATES PATENTS 1,867,331 7/1932 Sheehan et al 72252 2,029,915 2/ 1936 Fawell 72252 3,107,404 10/1963 Armand et al 164282 3,290,734 12/1966 Werth 164-282 CHARLES W. LANHAM, Primary Examiner A. RUDERMAN, Assistant Examiner US. Cl. X.R.

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