US1844107A - Operating mechanism for metal-cutting shears - Google Patents

Description

Feb. 9, 1932. J w, SHEPERDSON 1,844,1Q7

OPERATING MECHANISM FOR METAL CUTTING SHEARS Filed May 25, 1929 3 Sheets-Sheet l mar/03y J w. SHEPERDSQN 1,844,107

OPERATING MECHANISM FOR METAL CUTTING SHEARS 5 Sheets-Sheet 2 Feb. 9, 1932.

Filed May 25, 1929 OPERATING MECHANISM FOR METAL CUTTING SHEARS Patented F eb. 9, 1932 JED JOHN W. SHEPER-DSON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO MORGAN CON- CHUSETTS OPERATING MECHANISM FOR METALOUTTING SHEARS Application filed May 25,

The present invention relates-to operating mechanism for metal-cutting shears of the type known as flying shears, which are employed in steel mills to cut the rapidly moving hot rolled product of the mill into com- I mercial lengths as fast as it is delivered from the finishing rolls.

Such a shearing mechanism, employing a steam-operated piston and cylinder unit for securing the travel of the cooperating shear blades in unison with the stock, so as not to retard the-movement of said stock while the successive cuts are taking place, is shown and described, for example, in United States Letters Patent No. 1,521,514 of V. E. Edwards,

dated December 30, 1924. In the mechanism of. this Edwards patent, after each rapid swing of the cooperating shear blades in the direction of travel of the stock, there is necessarily a relatively slow return movement of the shear frame and its blades back to the normal open or rest position of the shear. That is to say, while the-working or cutting swing of the shear is secured with full steam pressure on one side (the upper side) of the shear-actuating piston, accompanied by the free exhaust of steam from the other or lower side of said pist0n,it is nevertheless a fact that on the return stroke of the shear actuating piston of this Edwards patent, said p ston is subjected to full steam pressure on both sides,the return movement, under these conditions, occurring only by reason of the fact that the under side of the piston presents a greater eifective area than the upper side. Consequently, the return stroke takes place at a relatively slow speed, in the operation of the shear of this Edwards patent.

Such a slow return stroke, which is characteristic of the action of all previous steamoperated flying shear mechanisms. serves well enough when the moving stock is being .cut up into relatively long pieces, as such lengths give ample time for the cooperating shear blades, after taking each cut, to'return to their normal stationary open positions. But for cutting the moving stock into shorter pieces, or even into longer pieces where the delivery speed of the stock is quite high, such a slow return movement of the flying shear 1929. Serial no. 386,012.

STRUCTION COMPANY, OF WORCESTER, MASSACHUSETTS, 'A CORPORATION OF MASSA- parts" is wholly unsatisfactory, and imposes very-serious limitations-on the output and operating efliciency duces said stock.

The present invention overcomes these difficulties by aconstruction which relieves the steam pressureon the upper side of the shearoperating piston at or near the end of the cutting stroke, so that its return stroke, for the'restoration open position, can take place at any speed desired. Other and further objects and adofthe shear blades to normal of the mill which provantages of the invention will be made apparent in the following detailed description thereof, in connection with which reference is had to the accompanying drawings, in which I Fig. 1 is a general view inside elevation, 1

partly in section, showing a flying shear to which the operating mechanism of my invention is applied.

F ig. 2 is a large scale longitudinal sectional view of the piston and cylinder unit, and associated valve parts, which are employed, according to my invention, for the operation of the shear.

Figs. 3 and 4 are diagrammatic views, similar to Fig. 2, on a smallerscale, showing the parts in different positions.

Figs. 5 and 6 are fragmentary sectional views illustrating the pilot valve construction which may be employed for the actuation of the main steam valve of the piston and cylinder unit, Fig. 5 being a section in the plane of line 5-5, Fig. 2, and Fig. 6 being a larger scale section in the plane of line 6-6, Fig. 5.

Like reference characters refer to like parts in the different figures.

Referring, first to Fig. 1, the shearing mechanism proper, which may be of substantially the same type as that shown and described in the aforesaid Edwards Patent No. 1,521,514, is mounted on a suitable base 1, the latter providing a trunnion 2 for the swinging shear frame 3. Said shear frame 3 provides the usual opening 4 for the continuous passage therethrough of the rapidly moving rolled product 5 of the mill, travelling in the direction of the arrow A on which, I

' to the transverse pivot shaft 11 of the blade.

8, as are also the upper ends of a pair oflinks 12, 12 (only one being shown), which are adapted to swing on'a fixedtrunnion 13 of the base 1. Also pivotally attached to the,

transverse shaftll are a pair of connecting rods 14, 14 (only one being shown), the latter-being connected to and operated from a reciprocating cross head 15, which is attached to a shear-operating piston 16, contained in the steam cylinder, designated as a whole by the numeral 17, of my invention.'

' Fig. 2 shows the piston 16in a position corresponding to the normal at-rest posi- 25 tion ofthe shea'r'frame'3, as shown in Fig.

1, said piston 16 being then in close proximity to the uppercylinder head 18, through which: passes the piston rod 19. As shown in Fig. 2, the cylinder '17 has associated there- 39 with the inclosing casing 20 of a slide valve 21, hereinafter termed the main valve, which is mounted in a suitably ported "sleeve 22 received in the bore of casing 20 and closed 'at its ends by the heads '23 and 24. Said casing 20'provides a pair of steam inlet connections 25 and 26'and a single exhaust steam connection 27 all in constant communication with the, interior of the lining sleeve 22.

Through suitable registering ports in said lining sleeve 22, communication of its interior is alsoadaptedto be established withsteam passages 28 and 29 opening into opposite ends ofcylinder 17, and exhaust passages 30 and 31 opening into said cylinder.

inwardly of and adjacent to the respective steam passages 28 and 29. Y x The main valve 21- provides two intermediate skirted piston portions 32 and 33, the

former controlling, as hereinafter described,

the steam and exhaust passages 28 and 30, respectively, and the latter controlling, as hereinafter described, the steam and exhaust .- passages 29 and 31, respectively. Beyond and in spaced relation to the portion 32, said main ,valve provides a guiding piston portion- 34, whose movement in the sleeve 22 gives the efi'ect substantially of a dash pot. At

' the oppositeend, said main valve provides,

in spaced relation to the portion 33, an .op-

crating piston portion 35, received in a largediameter extension 36 of the sleeve 22.

The main valve portion 35 is the means by which the entire valve 21, with its several parts32, 33 and 34, is shifted longitudinally in the sleeve 22, to obtain the working and return strokes ofpiston 16 w ithin the cylinder. In the normal atre'stfposition of the mechanism, as illustrated in Fig. 2, the main valve 21 occupies its extreme right hand position, owing to unbalanced steam pressure.

That is to say, while the portions 32 and 34,v

exposed to steam from inlet 25, balance each other, and. while the portion 35, because of bleed opening 37 therein is also substantially balanced, nevertheless the portion 33 has steam pressure on its left-hand side and only atmospheric pressure on its right-hand side, and thus the steam pressure normally. maintains the valve "in the position shown by Fig. 2. The maintenance ofpressure in the space 38 between the valve portion 35 and the head 24 is controlled by a pilot valve, the opera tion of which, as hereinafter described, procures the steam-actuatedmovements of main valve 21. Said .pilot valve and its appur tenant devices, which form no part of the present invention, may be of any suitable construction; as here'shown by way of example, a rotary pilot valve of the type disclosed in the aforesaid Edwards patent may be employed. To this end, as shown in Fig. 5, the main valve casing 20 has secured thereto on one side, in the vicinity of'the space 38, a pilot valve casing 39, the bore of which, on an axis at right angle to that of the main valve casing bore, receives a rotary valve member 40. Communicating'with and parallel to the bore of the pilot valve casing 39, are two pairs of diametrically opposite passages-41, 41 and 42 42, the last named having extensions 43, 43 that open into the space 38,

as shown in Fig. .2. These extensions, 43, 43 register with longitudinally extending recesses 44, 44 on, the interior wall of the space 38, as also shown in Fig. 2.

"The pilot valve 40 extends diametrically across the bore of its casing .39, and inthe position shown in Fig. 6, it blanks 0E and closes thetwo passages 42, 42 that communicate with the space 38. Pilot valve 40 is secured to the end of'a valve stem 45, by therotation of which said valve is carried into a succession of different positions, relative to the pairs of passages 41, 41 and 42, 42. That is to say, in the construction shown, the-valve 40 .is adapted t be moved, intermittently, through angles ofwforty-five degrees, in order first, to connect adjacent passages 41 and 42, and then, to blank ofi' either .pair of diametrically opposite passages,-'repeating this operation, for each operation of the shear.

able mechanisms, such as the ratchet mecha: nisms of the'afgresaid Edwards patent, or the pressure-controlled devices of the copending Fay and Dahlstrom application Serial No. 322,594, filed November 29,1928, may be employed; such pilot valve operating mechanism forms of itself no part of my invention, and hence need notbe shown or de- For operating the pilot valve 40, any suit-- scribed in detail herein. It sufficient to note that each operative movement of the pilot valve 40, to initiate a cut of the shear,

may be made responsive to the travel of the stock 5, and that each reset movement of the pilot valve 40 may be made responsive to the swing of the shear frame, all as fully described in the aforesaid Edwards patent, and as here shown schematically in Fig. 1. To this end, the stem of valve 40 carries a ratchet wheel 46, whose teeth are adapted to be engaged by a pawl 46, which is'pivotally carried at 47 by a bent lever 48, the latter being journalled loosely on the end of valve stem 45. The free end of said lever 48 is connected by a link'49 with the trigger mechanism 50 of the shear, the latter providing a finger 51, depending from a rock shaft 52 which is connected by an 'arm 53 with the link 49. When the finger 51 is knocked upwardly by the front end of the stock 5, such movement is communicated by the linkage and ratchet mechanism to effect a forty-five degree movement of the valve 40, thus to carry it from the diagonal position of Fig. 6 (or any other diagonal posi tion in which it is left) into either a vertical or horizontal position, as the case may be, thereby to establish communication between adjacent passages 41 and 42, in consequence of which the cut of the shear is inaugurated, as hereinafter described.

When the pilot valve 40 moves through forty-five degrees into the broken line position of Fig. 6, the two passages 41,41, which have a common exhaustoutlet 54 to the atmosphere, procure, by their thus established communication with the passages 42, 42, a sudden release of the full steam pressure that prevails in the space 38. Thereupon, the valve 21 shifts sharply to the left, as shown in Fig. 3, because the right-hand side of portion 35 has a larger area than the left-hand side of portion-33; in consequence of this, the pressure normally effective to push the valve to the right is overcome, and the preponderance of pressure in the other direction, procures a movement to the left. With this left-hand shift of valve 21, its portion 33 uncovers the exhaust passage 31 and covers the inlet passage 29, as shown in Fig. 3; in this way, not only is the ingress of live steam from inlet 26 to the interior of the cylinder 17 cut off. but the steam thenin said cylinder on the left hand side of piston 16 undergoes an immediate drop in pressure, because of the connection established by passage 31 with the exhaust outlet 27. This left-hand movement of valve 21 also carries the valve portion 32 to a position where it covers the exhaust passage 30 and uncovers the inlet passage 28 at the upper end of the cylinder. so

that the steam from inlet 25 exerts its full pressure against the right-hand side of piston 16 to move the latter rapidly, as shown in Fig. 3, for the operative stroke of the shear.

On this operative stroke, the pilot valve 40 is reset, by another movement through fortyfive degrees, to block 0d the communication between the passages 41, 41 and 42, 42. This may be effected, as described in the aforesaid Edwards patent, by the movement of the shear frame 3 itself, which takes place, as above described, onthe left hand stroke of piston 16, as shown in Fig. 3. The mechanism for thus resetting the pilot valve 40 forms no part of the present invention; said mechanism may be of the type shown and described in the aforesaid Fay and Dahlstrom application, or it may be, as shown in Fig. 1, of the character described in the aforesaid Edwards patent,

wheel 55, on-the valve stem 45, with which cooperates a slidable member 55 having a;

link connection 56 with a bell crank 57, the latter having a link 58 adapted for adjustable connection, as shown at 59, to the shear frame 3. When the latter makes its operative swing, the movement of member 55 imparts a forty-five degree movement to the pilot valve 40, to reset the latter in a position to blank off the, pairs of passages 41, 41 and 42, 42 from each other; this movement of the and involving a ratchet I pilot'valve shuts off the space 38 from the exhaust outlet 54, and thereby causes the steam pressure to build up in the space 38 (owing to the bleed passage 37), so that the main valve 21 is quickly moved from the position of Fig. 3 to the position of Fig. 4, the

latter being its normal position. With this movement of the main valve, the portion 32 thereof, as shown in Fig. 4, uncovers the exhaust passage 30 so as to connect the right hand end of cylinder 17 with the exhaust outlet 27 at the same time, the portion 33 of said main valve uncovers the inlet passage 29 and thereby allows the full pressure of steam from the inlet 26 to be exerted against the left hand side of piston 16, so as to produce a rapid return movement of said piston to the normal position shown inFig. 2. In this way, the return stroke of the shear frame 3.is effected, the same as the operative stroke,'by opening one end of the cylinder to exhaust, and by'making the full steam pressure effective on the other side of the piston; in other words, for each complete cycle of operation of the shear frame, operative swing and return swing, there is simultaneously procured an admission of live steam against one side of the piston, and an exhaust of steam from the other side toward which the piston move ment takes place. Thus the return swing of the shear frame may be made just as rapid and just as positiveamovement as the operativeswing.

Each of the exhaust passages 30 and 31 is provided with an adjustable valve 60, which may be manually set, as described in the aforesaid Edwards patent, to control the rate at whichthe steam, from one end or the other of the cylinder, is exhausted, both on the operative and on the return strokes. In this way, the speed of the operative or cutting stroke of the shear may be definitely and ac;' curately predetermined by the setting of the exhaust valve 60 inthe passage 31,-this valve being set in a position which corresponds to the particular speed at which the material 5 is being delivered from the mill. In like manner, the other exhaust valve 60 in the passage 30 can be set to obtain any desiredfspeed for-the return stroke of the shear frame.

5 As the piston .16 nears the end of said return stroke, it moves over the inner end of exhaust passage 30. In consequence of this, the end of the return stroke is cushioned by the steam that is trapped at this time between zo'said piston and the cylinder head '18, since such steam, with passage 30 covered by the' piston, has only the restricted entrance to said passage afforded by the shallow cylinder wall recess 30'. The piston 16 comes completely to rest at the end of the return stroke since the valve mechanism, as above described, has already been returned to the position shown by Figs. 2 and 4, where the steam pressure through passage 28 is cut off.

30 In this rest position, which disposes the shear in readiness for taking its next cut, the full pressure of the steam supply 26 is transmitted to the interior of cylinder 17 through the passage 29; this steam pressure in the rest or stationary position of the piston 16 becomes 7 effective on bothsides of said piston, due to the clearance or leakage space 17 provided between the piston and the wallof the cylinder 17 I Consequently, upon the next-ensuing l movement of main valve 21, to exhaust steam from the lower or left hand side of the piston simultaneously with the admission of steam to the upper or right hand side of the piston,

one end of said cylinder to steam pressure and the other to exhaust, and means. respon-' atin means therefor, to secure each cutting;

eachcutting stroke of the shear by opening one end of said cylinder to steam pressure and the other to exhaust, means responsive to the cutting stroke so initiated for shifting said valve means to open thefirst-named end of said said cylinder to exhaust and the other to steam pressure, thereby to produce the return of'said shear to normal rest or open position, and means to adjust the exhaust openings from each end of said cylinder, thereby to control the speed of both the-cutting andthe return strokes of said shear.

3. The combination with a swinging flying shear, of steam c linder and piston actuating means there or, to secure each cutting stroke of said shear and its return to open or rest position, a main steam Valve movable to admit steam under pressure against one side of said piston and to exhaust steam from the other side, thereby to efiect the cutting movement of said shear, a pilot valve movable to procure, by steam pressure, such movement of the main steam valve, means responsive to such cutting movement of the shear for resetting said pilot valve, and for procuring by steam pressure the return of said 'main steam valve to its normal position,

where-it exhausts steam from the first-named side of said piston and admits steam to the other side, thereby returning the shear to its normal rest or open position.

' 'JOHN W. SHEPERDSON.

sive to the cutting stroke so initiated for shifting said valve means to open the firstnamed end of said cylinder to exhaust and the other to'steam pressure, thereby to produce the return of said shear to normal rest or open position.

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