Rotary Trough Type Cooling Bed Run-in Apparatus

The present invention relates to a rotary trough type cooling bed run-in apparatus employed for guiding a small steel round bar rolled by a merchant bar mill to the upper input side of a cooling bed and allowing the bar to drop in aligned state on the cooling bed.

A known cooling bed run-in apparatus employed with a merchant bar mill includes a plurality of angle troughs each composed of an angle bar and arranged in rows corresponding to the number of the strands and ejecting levers which are assembled to the angle troughs in their line direction at equal spaces, whereby the levers are rotated and the rolled bars are ejected from the angle troughs onto a cooling bed to cool and straighten the bars. In this case, in consideration of the combination with the ejecting levers, the angle troughs are arranged in rows and in inclined relation and the number of the troughs is for example two in the case of a single-strand mill and four in the case of a two-strand mill, whereby the bar ejected from the angle trough rolls down the chute projected from the trough and falls into the first groove of the cooling bed. However, this prior art apparatus is disadvantageous in that each of the troughs is formed with an opening in its inclined upper front end so that at high speed operation of over 18 m/s the top of the bar projects and causes a bending to the bar, thus making the apparatus unsuitable for use as an attachment apparatus for high speed rolling purposes. Another disadvantage is that since the bar rolls down the chute, a wavy warpage is produced and retained in the bar even after the cooling and the pitch of the ejecting levers also has the effect on the wavy warpage. Still another disadvantage is that the time required for the bar to fall from the angle trough onto the cooling bed differs with the different troughs and consequently it is difficult to determine the proper ejection timing to eject each bar positively into one of the grooves of the cooling bed.

The present invention has been made to overcome the foregoing deficiencies in the prior art, and the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front view showing the general construction of an apparatus according to the present invention;

FIG. 2 is a sectional view taken along the line I--I of FIG. 1, showing the relative positions of the long troughs and the cooling bed for a single-strand bar mill in an embodiment of the invention;

FIG. 3 is a sectional side view of an embodiment of the long trough, showing its relation with a rotary guide and a slit cover;

FIG. 4 is a sectional side view showing another embodiment of the long trough;

FIG. 5 is a longitudinal sectional view of another embodiment, showing the relative positions of long troughs and a cooling bed for a two-strand bar mill; and

FIG. 6 is a longitudinal sectional view of still another embodiment, showing the relative positions of long troughs and a cooling bed for a multiple stranded bar produced by slitting a rolled billet.

Referring to FIGS. 1 and 2, each of turning arms 10 is pivoted to one end of a turning lever 9 fixedly mounted on a rotatable turning shaft 8, and pivoted to the other end of the arm 10 is an arm end of a rotary arm 12 secured to a long trough 11 which will be described later, whereby the long trough 11 is rotated about its axis in response to the rotation of the turning shaft 8. As shown in FIG. 3, each of the long troughs 11 is comprised of a steel pipe 14 formed with a longitudinal slit 13 and the long trough 11 is arranged to extend parallel to the turning shaft 8. A rotary guide 15 having a lateral opening extending in the same direction as the slit 13 is secured to each of the ends of the trough 11, and is rotatably mounted in a fixed position to a suitable support member. A slit cover 16 is secured to the support member so as not to interfere with rotation of the long trough 11 and the guide 15. Thus, when the long trough 11 is rotated so that the slit covers 16 face the slit 13, the slit is covered. When the long trough 11 is rotated further so that the slit 13 no longer faces the slit cover 16, the slit 13 is exposed downwardly. When the number of the strands is 1, the long troughs 11 are positioned relative to a cooling bed 4 as shown in FIG. 2, that is, long troughs 11 and 11a are arranged symmetrically and slit covers 16 and 16a respectively covering the slits 13 and 13a are arranged in such directions that they are inwardly upwardly inclined at an angle of about 45.degree.. As a result, when the long trough 11 and 11a are positioned so that the slits 13 and 13a respectively face the slit covers 16 and 16a, the slits 13 and 13a are covered by the slit covers 16 and 16a. When the long trough 11 or 11a is rotated so that the slit 13 or 13a faces downward, a rolled bar 3 or 3a placed in the long trough 11 or 11a is dropped through the slit 13 or 13a and the lateral opening of the rotary guide 15 or 15a to fall along a guide plate 17 or 17a into a first groove 6 of the cooling bed 4.

In the case of the above-mentioned singlestrand bar mill, the sequence of operations of the apparatus is as follows. The rolled bar is cut to required lengths by a shear (not shown) which is located at the delivery side of the final-stage rolling mill, and a sorter (not shown) which is located at the entry side of the long troughs 11 and 11a introduces the first one of the bars axially into one or the other of the left and right troughs (e.g., the trough 11). Then, this bar 3 is braked and stopped in place by a brake (not shown). During the interval a second bar 3a is introduced into the other adjoining long trough 11a and the long trough 11 is rotated so that the braked first bar 3 is dropped into the first groove 6 of the cooling bed 4. Then the bar 3 in the first groove 6 is transferred to the next groove 6a by a transfer means comprised of a plurality of parallel walking beams (not shown) and then the second bar 3a is similarly stopped and dropped into the first groove 6 which is now empty. Thus, by operation of the said walking beams the rolled bar 3 or 3a disposed in the first groove 6 of the cooling bed 4 is transferred to the next groove 6a and the bar in the groove 6a is transferred to the following groove 6b and so forth. During the latter interval the next bar 3 is introduced axially into the empty long trough 11. By thus repeating the similar sequence of operations, it is possible to successively drop the succeeding bars 3 and 3a into the groove 6 of the cooling bed 4.

It should be apparent without any detailed description that the long trough 11 may be comprised of, in place of the steel pipe 14, an angle steel 18 of substantially U-shape as shown in FIG. 4 so as to ensure the same effect.

The arrangement of long troughs 11 in a second embodiment of the invention adapted for a two-strand bar mill will now be described with reference to FIG. 5. The second embodiment differs from the first embodiment in that a similar pair of long troughs 11b and 11c having a slightly wider spacing are arranged side by side below the juxtaposed long troughs 11 and 11a and that the similar guide plates 19 and 19a are arranged between the upper and lower long troughs 11, 11a and 11b, 11c in addition to the guide plates 17 and 17a which are now respectively arranged between the lower long troughs 11b and 11c and the cooling bed 4. The sequence of operations is as follows. Two bars of No. 1 strand and No. 2 strand rolled parallel to each other are introduced at a different timing into the left and right or the upper and lower long troughs by the said sorter (not shown), in order to prevent the bar from crossing, because the bars are not cut at the same time and the cutting timing is different. Thus a first bar of No. 1 strand 3 is introduced into one of the upper left and right long troughs (e.g., the trough 11) and the bar 3 is stopped by braking. During the deceleration period, a first bar of No. 2 strand 3a is introduced into the right long trough 11a and stopped by braking. The first bar 3 which has been stopped is dropped into the first groove 6 of the cooling bed 4 and then transferred to the next groove 6a. The second bar 3a is successively dropped into the now empty first groove 6 and similarly transferred to the next groove 6a. During the period, third and fourth bars are respectively introduced into the lower left and right long trough 11b and 11c, and dropped into the groove 6 of the cooling bed 4 by the similar sequence of operations as above-mentioned. In this way, the same process of introducing the next bar into the empty long trough while the bar in the other long trough is being braked, is performed repeatedly and the bars are successively dropped into the groove of the cooling bed 4.

Referring to FIG. 6 showing another embodiment of the invention applied to a billet rolling with two-piece slitting, the arrangement of long troughs 11 is all the same with that of the previously described two-strand bar mill but an isolation partition 20 is vertically arranged between the left and right long troughs 11, 11b and 11a, 11c, and the cooling bed 4 is positioned such that the lower end of the isolation partition 20 is pointed toward the crest portion between the adjacent grooves of the cooling bed 4. This embodiment is also designed so that the two bar 3, 3a dropped at the same time into the groove 6 of the cooling bed 4 are subjected to continuous two-groove or by double pitch transfer. This is because two-piece slit bars are cut simultaneously by a shear (not shown) in a rolled billet and hence the bars must be introduced simultaneously into the left and right long troughs. In operation, the first bars 3, 3a are introduced simultaneously into the left and right long troughs of the upper or lower row (e.g., the trough 11, 11a) and then the second bars 3b, 3c are introduced into the long trough 11b, 11c of the other row while braking the first bars 3, 3a. Then the stopped first bars 3, 3a are dropped respectively into the groove 6, 6a of the cooling bed 4 and subjected to the continuous two-groove transfer as mentioned above. Then, the next bars 3, 3a are introduced into the empty trough 11, 11a while braking the second bars 3b, 3c. The second bars 3b, 3c are dropped in the same manner into the cooling bed 4 and transferred. Thereafter the same process is repeated alternately for the upper and lower troughs. The apparatus shown in FIG. 6 may be applied to two-strand rolling. In this case, it is only necessary that two-strand bars are stopped and then dropped simultaneously. In the case of a multiple stranded bar with three-piece slitting or over, it is only necessary to provide the same number of rows of the upper and lower long troughs as the number of pieces slit at a time.

It will thus be seen from the foregoing description that in accordance with the present invention, by virtue of the fact that the introduction of a bar into the long trough 11 is effected while its slit 13 is being covered by slit covers 16, it is possible to ensure a high speed rolling of over 20 m/s and greatly reduce the occurrence of ejection or bending of the bar. Further, due to the fact that the bar 3 is dropped over a very short distance into the groove 6 of the cooling bed 4 through the slit 13 opened downwardly by the rotation of the long trough 11, there is no danger of causing a wavy warpage in the bar during its dropping and the time required for dropping is reduced due to the reduced dropping distance. Still further, due to the reduced time difference in dropping of the bars from the long troughs, the timing of dropping of bars can be easily adjusted. Still further, due to the fact that the bar is dropped by gravity fall due to the rotation of the long trough instead of the ejection operation performed by the rotation of the levers as in the prior art apparatus, the length of the long troughs can be selected for example in the range of 4 to 6 m. This length is about 10 times the conventional length of 0.6 to 0.6 m. Where the two-strand four-trough type is applied to the two-strand bar which is slit a rolled billet, the bars are slit simultaneously and consequently if the upper two long troughs and the lower two long troughs are alternately and simultaneously rotated to effect the simultaneous dropping, the timing of dropping can be controlled in the same manner as in the case of the single-strand bar mill, thus providing a sufficient processing time.

As mentioned above, the present invention is very useful industrially in that the rolling of small steel rounds can be effected at high speed, that there is no danger of causing wavy warpage, that the timing of dropping can be adjusted easily and so on.