US3149520A

US3149520A - Automatic cycling of shear control

Info

Publication number: US3149520A
Application number: US79395A
Authority: US
Inventors: Harry K Fish; Okey E Cline
Original assignee: National Steel Corp
Current assignee: National Steel Corp
Priority date: 1960-12-29
Filing date: 1960-12-29
Publication date: 1964-09-22
Anticipated expiration: 1981-09-22

Description

Sept. 22, 1964 H. K. FlSH ETAL 3,149,520

AUTOMATIC CYCLING OF SHEAR CONTROL Filed Dec. 29, 1960 2 Sheets-Sheet 2 FIGZ CYCLING CONTROL CONTROL Tl ME R TIMER 32 3s 39 DRIVE 30 3| DRIVE 35 37 DRIVE 42 D FIXED DISTANCE 0 TRAVEL G O O O O O O O O O O ROTATION m RADIANS EQUAL TO TRAVEL OF SLAB BETWEEN DETECTOR 35 AND SHEAR 34 F zzvmvroxs HARRY K. FISH AND OKEY E CLINE TIMER TTORNEYS Q '45 0 8 00000 ]E OOOQQQQQQOQ United States Patent 3,149,520 AUTOMATEQ CYL1NG G1 SHEAR CONTRQL Harry K. Fish and Oitey E. Cline, Weirton, W. Va, assignors to National Steel orporation, a corporation of Delaware File-d Dec. 29, 1960, Ser. No. 79,395 2 Claims. (Cl. Sit-2&8}

The invention relates to automatic control in a continuous rolling operation.

The possibility of delays in a rolling mill precludes many measures which would contribute to the quality of the finished product. For example, the configuration of the leading and trailing edges of the hot metal slab as it is reduced to fiat rolled product having about of its original thickness has long presented a problem in hot-strip rolling mills. The mewl is deformed Without restraint at the leading and trailing edges and takes on strmge configurations along its longitudinal dimension. Such configurations present mechanical handling problems in the mill and subsequent thereto. These problems are accentuated as the metfl approaches and passes through the finishing stands.

It is the purpose of the invention to remove these difficulties with the leading and trailing edges of the flat rolled product without stopp ng the metal and without interrupting the continuous hot-strip rolling mill operations.

In describing the invention reference will be had to the accompanying drawings in which:

FIG. 1 is a schematic illustration of a hot-strip rolling I mill;

FIG. 2 is a diagrammatic representation of apparatus embodying the invention;

FIG. 3 is a representation of apparatus usable with the invention;

FIG. 4 is a schematic representation of an electrical control apparatus usable with the invention.

In the hot-strip mill of FIG. 1, metal slabs to be rolled are brought up to the proper temperature, as determined by the product being rolled and the time the slab will be in the rolling mill, in slab furnace 11. The slab normally will be red-hot and have a temperature between 2,000 F. and 2400 F. The slab is moved onto the travel path 12 defined by the rolling mill and passes through the

roughing stands

14, 15, 16 and 17. Normally the distance between each roughing stand is such that the slab completes its pass at one roughing stand before starting its pass at the next roughing stand. After completing its passage through the roughing stands the metal will have been reduced from its original thickness of 4 to 7 inches to approximately 1% inches and is commonly referred to as a bar.

After leaving the last roughing stand 17 the bar travels along the roll-out table 20 under impetus imposed by that stand. The bar then passes onto driven conveyor table 22 which moves the bar at a predetermined speed into the finislr ng stands 23. Flat rolled product exits from the finishing stands and travels along cooling table 24 to a coiling station 25.

As mentioned previously slabs of upwards of tons in weight are reduced in thickness from about 4 inches to gauges as low as 0.04 inch. In so doing a slab approximately feet in length may be elongated to over "Ice 2,960 feet in length. The lateral edges of the metal are controlled during the rolling processes by vertical edging rolls (not shown) so that straight lateral edges result. The leading and trailing edges cannot, of course, be so controlled. Metal at these edges takes on various configurations known as fishtails or alligators. The fiat rolled product may have a long centrally located extension, or a hollow center, or be extended along one or another of the lateral edges. These less than full width configurations may exceed 10 feet in length.

The invention includes the idea of automatically cropping the leading and trailing edges of a hot metal bar ahead of the finishing stands, without stopping the bar. Numerous problems are presented in attempting to carry out this idea. For example, the desired leading edge cut differs from the desired trailing edge cut; a slightly convex cut at the leading edge provides better feed through finishing stand rolls; a squared off straight cut provides the best trailing edge. Also the travel speeds of the leading and trailing edges through the mill, at any given point near the finishing stands, usually differ greatly since the speed of the trailing edge is controlled by the finishing stand operation, which cannot be modified to allow proper cropping of the trailing edge, while the leading edge speed is under other control. Additionally, shearing a bar of approximately one inch thickness requires a shear of some strength and power; such a shear cannot be operated instantaneously. The invention overcomes these problems by automatically cycling a crop means in synchronism with the individual movement of the leading and trailing edges of a hot metal bar to affeet the desired cropping at both these edges.

A specific embodiment of the invention is shown diagrammatically in FIG. 2. A hot metal bar, traveling at a speed as determined by the last roughing stand, is detected by a hot metal detector 30 which generates a signal due to the presence of the bar on the travel path 12. The hot metal detector 30 signal operates holding table drive means 31 through control means 32 to bring the speed of the bar under control on holding table 33. The bar is then moved by driven conveyor table 22, at a predetermined speed consistent with the finishing operation, toward a rotary crop shear 34 and the finishing stands 23. At a fixed distance before the rotary crop shear a second hot metal detector 35 detects the leading edge of the bar. Hot metal detector 35 generates an electrical signal which is correlated with the movement of the leading edge of the bar by first timer means 36 connected to conveyor drive means 37. The signal is fed to electrical cycling control apparatus 38 which controls electrically powered shear drive means 39 for the rotary crop shear 34.

In controlling the shear drive means 39, to effect cropplug of the trailing edge of the slab, movement of the trailing edge is coordinated with the signal from the hot metal detector as by idler roll 4%) and second timer means- 41.

The rotary crop shear 34 employs two rotary drums having leading

edge cutting blades

42 and 43 and trailing

edge cutting blades

44 and 45 mounted thereon. The drive means 39 cyclically operates the rotary crop shear 34 to affect a leading and trailing edge out by rotating the rotary drums through a cutting swing of 220 and a resetting swing of reverse rotary motion of 40 The hot metal detectors and may take the form of any suitable conventional radiation sensitive device which generates an electrical signal in response to the presence of a bar on travel path 12 in its field of sensitivity. The timer means 36 and 41 may also be of any conventional design for example a pin wheel timer.

The function and operation of timer means in the inven tion will be described with reference to FIGURES 2 and 3. In this embodiment a pin wheel 46 is rotated by drive means 37 in synchronism with bar movement on the driven conveyor means 22. An electrical signal to input means 47 depresses one or more of the pins on the wheel 46 as determined by the duration of the electrical signal. The depressed pin(s) travel through are 48 to output means 49. The are 48 is functionally equated to the fixed distance between hot metal detector 35 and the rotary shear 34 so that the time between input and output is equal to the time required for the leading edge of the bar to travel between the hot metal detector 35 and the shear 34. Considering timer means 41, a pin wheel is rotated by idler roll 4% the electrical input signal is generated by the trailing edge of the slab, that is absence of the slab from the field of sensitivity of the hot metal detector 35.

For a detailed description of a specific embodiment of cycling control apparatus 38 reference will be had to FIG. 4. As a hot metal bar is detected by the hot metal detector 35 a signal is generated which closes switch 56 thereby energizing relay 51. Relay 51

closesswitches

52 and 53 and opens

switches

54 and 55. Closing switch 53 energizes the adjustable relay 57 which closes switch 58 energizing relay 59 and in turn closing switch 6%. The relay 59 also opens switch 63 which deenergizes relay 64 to cause a timed opening of switch 65.

Concerning the operation of the apparatus just described, the operation of relay 57 is adjustable to afi ect the desired amount of front end cut. The mill operator can adjust the time, after closing of the switch 53, during which the relay 57 will close the contact 53. This in turn times the input signal to the pin wheel timer and permits adjustment of the length of metal cut from the front end to be set or modified as necessary. The timed opening of the switch 65 in response to relay 64 determines the number of pins on the pin wheel 48 which will be depressed. This choice permits a wide selection of electrical elements to be used to actuate the shear drive 39, since their sensitivity, for example the lock in time of a relay, can be compensated for by the number of pins depressed.

Rotation of the pin wheel 46 is synchronized with the movement of the leading edge of the slab as previously described and, as the output contact 49 closes switch 67, relay 68 is energized actuating the shear drive 39 which in turn rotates the rotary crop shear 34 so that the

leading edge blades

42 and 43 contact the bar to crop a predetermined portion of the slab while it is moving toward the finishing stands 23. The cycling control apparatus thus far described provides means for cropping the leading edge of a bar in response to an electrical signal generated by the presence of the bar in the field of sensitivity of the hot metal detector 35.

While the hot metal bar is passing through the rotary crop shear 34, and into and through the finishing stands 23, trailing edge cutting blades 44 and are positioned for a trailing edge cut.

Switches

52 and 53 remain closed while

switches

54 and 55 remain open constituting, in part, means for alternating leading and trailing edge cuts.

When the trailing edge of the bar passes hot metal detector 35, switch is opened, deenergizing relay 51,.

and opening switches 52 and 53 while closing switches 54 and 55. The closing of switch energizes adjustable relay 71 closing switch '71 and energizing relay 72 which in turncloses switch 74 and opens switch 75. Opening of switch 75 deenergizes relay 76 to open switch 78 after a time delay. With the closing of

switches

54 and 74 and before opening of switch 78, relay 79 is actuated to provide an input signal for the timer means 41. The return signal from timer means 41 closes contact 80 to energize the shear drive control relay 68 and effect cropping of the railing edge in synchronism with its movement through the rotary crop shear 23. The length of metal cut from the trailing edge is adjustable through adjustable relay 70 and the duration of the input signal to the timer means 41 is determined by relay 76 in a manner as described in relation to the leading edge cut. It can be seen that means are provided for cropping the trailing edge of a bar during the absence of a bar from the field of sensitivity of the hot metal detector 35 occurring after the leading edge cropping cycle.

Apparatus has been described which, in response to radiation sensitive electrical means, will automatically take control of a bar in a continuous hot strip rolling mill after it leaves the roughing stands and before it enters the finishing stands; control the bar motion before entering the finishing stands; and control the action of a rotary crop shear utilizing timer means to synchronize movement of both the leading and trailing edge of the bar with rotation of the shear cutting blades.

While the specific embodiment of the invention has been described it is understood that various modifications may be resorted to without departing from the spirit of the invention. Therefore the limits of the invention are to be defined by the appended claims.

We claim:

1. Apparatus for automatically cropping the leading edge of a hot metal bar during movement of the bar toward rolling mill finishing stands and cropping the trailing edge of the bar during movement of the bar through the finishing stands comprising:

driven conveyor means for moving a hot metal bar at a predetermined speed into finishing stands,

crop means located in the travel path of the hot metal bar between the conveyor means and the finishing stands,

hot metal detector means operatively located along the travel path of the hot metal bar a predetermined fixed distance ahead of the crop means for detecting the leading edge and trailing edge of the hot metal bar and generating a signal in response to each,

idler means for measuring the speed of the hot metal bar moving through the finishing stands, electrically powered drive means for the rotary crop means, and

electrical control means, responsive to the hot metal detector means, connected between the hot metal detector means and the electrically powered drive means for the crop means to actuate the crop means, including first timer means coupled to the driven conveyor means to synchronize movement of the crop means and the hot metal bar for cropping the leading edge of the bar, and second timer means coupled to the idler means to synchronize movement of the crop means and the hot metal bar for cropping the trailing edge of the hot metal bar.

In a continuous hot strip rolling mill, apparatus for automatically cropping the leading edge of a hot metal bar while the bar is approaching finishing stands and cropping the trailing edge of the bar while the bar is being rolled in the finishing stands comprising:

driven conveyor means for moving a hot metal bar at a predetermined speed along a predetermined travel path approaching the rolling mill finishing stands,

crop means operatively located along the travel path of the hot metal bar,

electrically powered drive means operatively connected.

to the crop means to effect a leading edge out and a trailing edge out upon passage of the hot metal bar,

hot metal detector means operatively located along:

the travel path of the hot metal bar ahead of the crop means for detecting the leading edge and trailing edge of the hot metal bar and generating a signal in response to each, and

crop control means electrically connected between the 5 hot metal detector means and the powered drive means for the crop means including first timer means for synchronizing movement of the crop means and the hot metal bar responsive to the speed of the driven conveyor means to control cropning 10 of the leading edge of the bar, and means including second timer means for synchronizing movement of the crop means and the hot metal bar responsive to the speed of the bar as controlled by rolling to control cropping of the trailing edge of 15 the hot metal bar.

References tlited in the file of this patent UNITED STATES PATENTS 2,070,537 Matthews Feb. 9, 2,211,362 Bennett Aug. 2,634,811 Schaelcrin Apr. 2,692,361 Asbury et a1. Oct. 2,995,968 Tomherg Aug. 15, 1961 FOREIGN IATENTS 322,695 Etaly Mar. 214,66 Australia June OTHER REFERENCES Automation, December 1959, pp. 71-73.

Claims

1. APPARATUS FOR AUTOMATICALLY CROPPING THE LEADING EDGE OF A HOT METAL BAR DURING MOVEMENT OF THE BAR TOWARD ROLLING MILL FINISHING STANDS AND CROPPING THE TRAILING EDGE OF THE BAR DURING MOVEMENT OF THE BAR THROUGH THE FINISHING STANDS COMPRISING: DRIVEN CONVEYOR MEANS FOR MOVING A HOT METAL BAR AT A PREDETERMINED SPEED INTO FINISHING STANDS, CROP MEANS LOCATED IN THE TRAVEL PATH OF THE HOT METAL BAR BETWEEN THE CONVEYOR MEANS AND THE FINISHING STANDS, HOT METAL DETECTOR MEANS OPERATIVELY LOCATED ALONG THE TRAVEL PATH OF THE HOT METAL BAR A PREDETERMINED FIXED DISTANCE AHEAD OF THE CROP MEANS FOR DETECTING THE LEADING EDGE AND TRAILING EDGE OF THE HOT METAL BAR AND GENERATING A SIGNAL IN RESPONSE TO EACH, IDLER MEANS FOR MEASURING THE SPEED OF THE HOT METAL BAR MOVING THROUGH THE FINISHING STANDS, ELECTRICAL CONTROL MEANS, RESPONSIVE TO THE HOT METAL DETECTOR MEANS, CONNECTED BETWEEN THE HOT METAL DETECTOR MEANS AND THE ELECTRICALLY POWERED DRIVE MEANS FOR THE CROP MEANS TO ACTUATE THE CROP MEANS, INCLUDING FIRST TIMER MEANS COUPLED TO THE DRIVEN CONVEYOR MEANS TO SYNCHRONIZE MOVEMENT OF THE CROP MEANS AND THE HOT METAL BAR FOR CROPPING THE LEADING EDGE OF THE BAR, AND SECOND TIMER MEANS COUPLED TO THE IDLER MEANS TO SYNCHRONIZE MOVEMENT OF THE CROP MEANS AND THE HOT METAL BAR FOR CROPPING THE TRAILING EDGE OF THE HOT METAL BAR.