US2061659A - Apparatus for shearing - Google Patents

Description

Nov. 24, 1936. L/IVERSEN 2,061,659

APPARATUS FOR SHEAR ING Filed July 22, 1932 5 Sheets-Sheet 1 INVENTOR L. IVERSEN Nov. 24, 193.6.

APPARATUS FOR SHEARING 5 Sheets-Sheet 2 Filed July 22, 1932 lIII/IIIIIIIIIIII l N V E N TO R Nov. 24, 1936.

L. IVERSEN ,659

APPARATUS FOR SHEAR ING Filed July 22, 1932 v 5 Sheets-Sheet 3 L. IVERSEN Nov. 24, 1936.

APPARATUS FOR SHEARING Filed July 22, 1932 5 Sheets-Sheet 4 INVENTOR Nov. 24, 1936. L. IVERSEN v APPARATUS FOR SHEARING 5 Shets-Sheet s Filed July 22, 1952 rrrrr no "MENTOR Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE APPARATUS FOR SHEARING tion of Pennsylvania Application July 22 1932, Serial No. 623,930

13 Claims.

The present invention relates broadly to the art of cutting material, and more particularly to the shearing of metal strips, rods, bars and the like. While utility of the invention is not limited to the metal working art, the invention is particularly adapted thereto, and will be described in connection therewith. It is to be understood, however, that the word strip as hereinafter utilized is a generic term used by way of definition and not by way of limitation, and inclusive of metallic or non-metallic shapes or pieces adapted to be sheared while in motion.

In the art to which the present invention relates, the demand for so-called flying shears has been a rapidly increasing one. As the speeds of delivery of strip material have increased, the diiiiculties of actuating flying shears have proportionately increased. The principal difliculty encountered has been that of maintainingsuch a speed relationship between the shear and the delivery speed as to give the proper accuracy in the length of the sheared pieces.

With ordinary flying shears of the rotary type adapted to cut successive lengths from a moving strip, the length cut depends upon the speed relation maintained between the delivery speed of the strip and the peripheral speed of the shear blades. It is evident that if the speed of the blade be increased in relation to the speed ofthe strip, shorter lengths will be cut, while if the speed of the blades isdecreased in relation to the speed of the strip, the lengths out will be longer. Ittherefore follows that the problem of cutting successive equal lengths with great accuracy depends upon maintaining very closely a predetermined speed relationship, between the shear blades and the strip. At the same time the structure must be such that it is possible to vary at will such relationship so that changes in the lengths cut may be efiected if desired.

. It will be understood by those skilled in the art that flying shears are ordinarily associated with a rolling mill, and are adapted to shearthe material; as it is delivered by a stand of rolls in I such mill. The problem of shearing is made more difiicult by the fact that with the ordinary means of driving the mill stands the speed of the driving motor is subject to all manner of variations such as occurwith changes inload, voltage, field excitation, temperature and the like. The motor driving the shear is also subject to similar speed variations. .form length of cut cannot be maintained by merelyinitially se'tting the speed of the, shear motors in definite relation to the speed. of the the desired accuracy of shearing may becon'tinu- Itis thereforeuevident tliat a unimill motor. It is necessary, if accuracy is to be obtained, to maintain the initial relation in spite of variables such as above referred to.

In an efiort to'overcome the difliculties heretofore encountered, difierent forms of speed gov- 5 erning devices have been utilized. Such devices have operated on the principle of causing the shear motor to follow speed changes of the mill or of the strip. It is an inherent feature of such governing devices, however, that they must follow with a greater or less time lag any incipient change in speed of the primary or governing member. They cannot anticipate changes. It is therefore necessarily true that the governed member likewise lags in its response, so that while the predetermined initial relationship may be approximated at times, it is not absolutely maintained.

The difiiculty could of course be obviated insofar as the speed relationship is concerned by positively driving the shear through a gear train from a stand of rolls. Such a gear train, however, would involve the difficulty of making gear changes for changes in the length of cut. Gearing is also objectionable for the reason that it 25 is inherently incapable of making automatic compensation for change in the diameter of the rolls in the mill as they are subjected to dressing operations. Thus even if material were always delivered by the same roll stand, gearing would not be practical. When it is considered, however, that it is desirable to deliver material sometimes from one stand in the train and sometimes from another, it will be apparent that the objections to gearing are further increased. This is particularly true since in ordinary continuous mills the different stands are driven at successively increasing speeds and gearing which was suitable 'for one stand would not be suitable for another stand.

It is also true that such gearing necessitates a fixed relationship between the shear and a roll stand, 'the construction not being one which adapts itself to efficient adjustability. l

The present invention has for its objects to overcome the objections inherent to shearing systems asheretofore proposed, to obviate the limiftations incident theretO and 'to provide a meth- 0d and apparatus of shearing by means of which ously effected irrespective of variables of the character referred to and without limitation as to changes in the diameter of: the rolls which are effecting delivery.

. Another jobject of the invention is to provide a method and apparatus for shearing characterized by the ability to maintain the speed of the strip being sheared even after it has left the delivery stand of rolls, and thereby enable accuracy of shearing throughout the entire length of the strip.

In the accompanying drawings there are shown certain preferred embodiments of the present invention, the drawings being more or less diagrammatic for purposes of giving a clearer understanding of the fundamental principles underlying the invention. In the drawings:

Figure 1 is a diagrammatic top plan view of an installation embodying the present invention;

Figure 2 is a diagrammatic side elevation of the installation illustrated in Figure 1', the shears being shown in section;

Figure 3 is a top plan view, on an enlarged scale, of a portion of the strip feeding means effective for maintaining the strip speed after it has left the mill; I

Figure 4 is a sectional view on the line IV-IV of Figure 3, looking in the direction of the arrows;

Figure 5 is a transverse sectional view on the line V-V of Figure 3, looking in the direction of the arrows;

Figure 6 is an end elevational view of a portion of the adjusting mechanism of Figure 3;

Figure 7 is a view generally similar to Figure 1, but illustrating a slightly modified embodiment of the present invention;

Figure 8 is a view partly in section and partly in side elevation, on an enlarged scale, of a portion of the apparatus of Figure '7; and

Figure 9 is a detail plan view, on an enlarged scale of a portion of the table of Figure 8.

Referring more particularly to Figure 1 of the drawings, there are illustrated successive roll stands 2, 3, 4 and 5 through which material being rolled is adapted to pass in the direction indicated by the arrow A. The desired roll or rolls of the respective stands are driven by gearing 6, 1, 8 and 9, the gearing as usual being such that the successive rolls are driven at higher and higher speeds as required by reason of elongation of the material resulting from reduction. The gearing is in turn driven by motors III, II,

l2 and II.

The motors ll, [2 and I4 are illustrated as having respectively connected thereto alternating current generators l5, l6 and I1. These generators are preferably of the synchronous type directly connected to the motors.

Cooperating with the last stand of rolls 5 is a. delivery table l8 over which the material travels to a shear stand l9. Referring to Figure 4, this shear stand supports shear rotors 20 and 2| suitably intergeared by means of gears 22 whereby a predetermined speed and angular relationship of the rotors is maintained. Each of the rotors may be provide with a blade 24, which blades are effective when in the position illustrated in Figures 2 and 4 for effecting a shearing operation on any material in position between the rotors.

Referring to Figure 1, for driving one of the rotors there is illustrated a hydraulic motor 25 adapted to be driven by a displacement pump 26, the pump and motor being operatively connected by suitable pipe lines 21. It will be understood that the pump may be of any well known commercial type having a control 28 whereby the quantity of fluid displaced per revolution of the pump may be varied, and a corresponding variation in the speed of the motor 25 thereby obtained. Other well-known forms of variable speed drive may be utilized instead of the variable displacement hydraulic pump, such as shown in Figure 7, for example.

The hydraulic mechanism above described is more fully described and claimed in my United States Patent No. 2,004,871, dated June 11, 1935.

For driving the pump 26 there is shown an alternating current motor 29. By maintaining a definite speed relationship between the motor 29 and any one of the roll stands 3, 4 or 5, depending upon which roll stand is performing the final operation on the material and therefore constitutes the delivery stand for the material, the lengths sheared will have the desired accuracy. Such a result is obtained in accordance with the present invention by providing a switch 30 adapted to electrically connect any one of the alternating current synchronous generators I5, IE or IT with the alternating current motor 29. In Figure 1 the alternating current motor 29 is shown as electrically connected to the generator I5, whereby the generator and the motor will operate at synchronous speeds. By moving the switch 30, the motor 29 may be electrically connected either to the generator IE or the generator ll. It is of course characteristic of a synchronous motor that it follows in speed the speed of the generator supplying current to it, being held in step by the frequency of the electrical alternations as effectively as though driven from the generator by positive mechanical gearing. The system illustrated therefore provides an electrical tie of a synchronous nature between any desired roll stand and the shear so that the shear may be driven by and in step with the delivery speed of such stand. Since the tie is an electrical one as distinguished from a mechanical one such as effected by gearing, it will be apparent that the shear may be positioned at any desired distance from the mill itself.

Since the speed of the rolls of the different stands varies, it will be understood that in order to obtain the advantages of the present invention it is necessary to drive the generators l5, I6 and I! in such manner that the frequency of the current supplied thereby shall be proportional to the angular velocity of the respective rolls with which they are associated in case the rolls are of the same base diameter, or proportional to the surface speeds of the rolls if the rolls are of different base diameters. If this is done, the synchronous motor driving the shear will maintain a speed proportional to the speed of the roll stand which governs it. The frequency of the current supplied by a generator depends upon the angular velocity of the rotor of the generator and the number of poles in the field of the generator. If the three generators all had the same number of poles, and were driven at the same speed as the rolls of their respective stands, the frequency would vary with the angular velocity of the rolls. It is, however, more convenient to drive the generators directly from the mill motors. Since these motors ordinarily have the same speed, the desired roll speed is obtained by the gear ratio of the gearing 6, l, 8 and 9. Since, as before pointed out, the gear ratio is such that the speeds of the rolls increase progressively in the successive stands, and since the generators are driven at the same speed, it is necessary in order to obtain the desired frequency, to change the number of poles in the different generators, the change in the number of poles increasing in definite ratio to the different gear ratios. In other words, the product of the number of poles of the generator and the speed ratio between the motor and the rolls must be constant.

For purposes of illustration, and by way of ex ample only, it may be assumed that the gear ratio of the gearing 1 is 2 to l and that the generator l5 has 8 poles. gear ratio by the number of poles is 16 and the frequency in cycles per second for every hundred R. P. M. is 13%,. If the gear ratio of the gearing 8 is 1.6 to 1, and the generator l6 has 10 poles, the product of the gear ratio and the number of poles will be 16, thereby likewise giving a frequency of 13 cycles per second for every hundred R. P. M. of the rolls. Likewise, if the gear ratio of the gearing 9-15 1 to 1 and the generator I! has 12 poles, the product of the gear ratio by the number of poles will be 16 which will result in a frequency of 13 cycles per second for every hundred R. P. M. of the rolls. It is thus seen that the motor 29 will always operate in predetermined speed relation to the particular stand of rolls to which it is electrically tied. In case, for example, the switch 30 is so disposed as to electrically tie the motor to the generator II it will operate at a higher speed than in case the switch 30 is in the position shown, since the rolls in the mill 5 are operating at a higher speed than the rolls in the mill 3. If any variation in the length of cut is desired, it may be easily effected by actuating the control 29 and thereby changing the speed ratio in the hydraulic transmission. Small differences in roll diameters due to roll dressing may be compensated by further slight additional adjustment of the speed ratio in the hydraulic transmission of the shear drive per se. The mechanism as thus far described provides means for maintaining the desired speed relationship so long as the material is being delivered by one of the roll stands. As soon, however, as the material leaves the last roll stand it is necessary to maintain the speed ii the same shearing relationship is to be maintained. This may be accomplished in accordance with the present invention byproviding a pair of pinch rolls3l and 32 (Figures 3 and 4) and providing one of the rolls with a. cone pulley 33 adapted to be driven from the motor 29 through the medium of a cone pulley 34 and belt 35. Cooperating with the belt is a slack adjuster 36 by which the desired tension is automatically maintained. Under normal conditions the pinch rolls 3| and 32 will be driven at the same speed as the motor 29 and the diameters of the pinch rolls will be such that their peripheral speed will be the same as the delivery speed of the material.

To compensate for slight changes such as required for roll dressing and the like, and to maintain the pinch roll speed in synchronism with the delivery speed of the material, there is provided a belt shifter 31 by means of which the belt may be adjusted with respect to the pulleys so as to increase or decrease to a slight extent the speed of the pinch rolls relative to the speed of the motor 29. As illustrated more particu-' larly in Figure 5 of the drawings, the belt shifter 31 is carried bya screw 38 operable through the medium of a, hand wheel 39. It will be apparent that rotation of the hand wheel in one direction or the other will be effective for producing a corresponding movement of the belt shifter and thereby of the belt. Carriedby the screw shaft 38 is a bevel gear 40 cooperating with a similar The product of the gear ll on an indicator screw 42. The indicator screw carries a pointer 43 cooperating with a scale 44. The scale may be calibrated to read in any desired figures. Conveniently, however, it will represent roll diameter and will therefore enable the proper adjustment to be .quickly made for any change in the roll diameter of the delivery stand.

In the form of the invention shown, the top pinch roll 3| is carried by a shaft 45 journalled in beams 46 having a pivotal'mounting 41, .the desired frictional relationship between the pinch rolls being obtained through the medium of springs 48 effective for normally swinging the beams in a clockwise direction to bring the pinch rolls together.

The present invention also lends itself to the cropping of a predetermined length from the leading end of each strip of material. As is well understood in the art, the length of the first or cropping cut when the shear is accelerated from rest will be determined by the time of arrival at the shear of the leading end of the strip with relation to the position of the shear knives as they approach the shearing position. The time required for a given acceleration of the shear to a certain speed is constant, depending upon the characteristics of the system. If the shear begins to accelerate from a definite position of rest, the length of the crop will depend upon the position of the leading end of the strip when the acceleration begins.

Figure 7 illustrates more particularly an embodiment of my invention adapted for starting and stopping the shear for cropping. In this other pair together and maintains a constant belt length, the efiective diameter ratio being varied at will. Obviously other forms of variable speed drive may be employed, as, for example, ordinary cone pulleys such as shown in Figures 3 and 4 for driving the pinch rolls.

Referring again to Figure 7, a limit switch 52 adapted for stopping the shear in a definite but adjustable position is provided. This limit switch may be driven through a suitable gear ratio from the shaft of a D. C. motor 53 connected to the synchronous motor 29', corresponding to the motor 29 before described, by a suitable coupling. The function of the D. C. motor is to accelerate the shear and the synchronous motor quickly to the synchronous speed, the ordinary synchronous motor (even one of the so-called self starting type) not being well adapted for rapid acceleration of heavy parts. Other types of synchronous motors known to the art which are :better adapted for accelerating a load may also be used, but forpurposes of illustration a separate D.. C. motor is here shown. For starting theshear a flag switch 54 located a suitable distance ahead of the shear completes a control circuit which causes the starting of the D. C. motor. A magnetic brake 55serves to stop the shear in the positiondetermined by the limit switch setting.

vwhen the coil is energized.

The wiring diagram, whereby the functioning of entire system may be understood, is also shown. This diagram is elementary in character and may be modified in various ways well known to the art. 56 is an operating coil for throwing a suitable three pole oil switch 51 by means of which the main circuit of the synchronous motor may be closed after the D. C. motor has brought the system up to synchronous speed.

58 is a contactor actuated by a suitable coil, and arranged with an adjustable time relay so that when the coil is energized the closing of the contactor may be delayed until the proper time for throwing the switch 51. Line switches 59 and 60 are also provided.

The flag switch and the limit switch are shown diagrammatically at 54 and 52, respectively. 6| is a D. C. starting panel carrying three contactors 62, 63. and 64 actuated by a coil 65, and adapted to close their respective circuits 66 is the coil of magnetic brake 55, here shown as a series brake. 61 is the armature of the D. C. motor 53, here shown as having a series field 68. Starting resistance 69 may be provided which is adapted to be cut out of the armature circuit in the usual way, as the motor comes up to speed.

The operation is as follows: The shear is at rest in the position in which it has previously been stopped by the limit switch. The leading end of the strip passes over the fiag switch shown diagrammatically at 54' and closes the circuit through coil 65 which, being energized, closes contactors 62, 63, and 64. Closing of contactor 62 puts the limit switch 52' in parallel with the flag switch 54'. Closing of contactor 63 completes the D. C. motor circuit and starts the motor to make the cropping cut. Closing of contactor 64 energizes coil 58 which acts to close its contactor after the proper time interval as described above, and so energizes coil 56 which throws the main switch 51. Both D. C. and synchronous motors are now running, and the strip is being sheared to length. After the trailing end of the strip runs out from over the flag switch, this switch opens the control circuit which, however, is still closed through the parallel circuit which contains the limit switch 52. When this has been rotated by the rotation of the shear to a predetermined point, this circuit is also opened and coil 65 being de-energized, contactors 62, 63, and 64 drop out together and open respectively the limit switch circuit, the D. C. motor circuit and the synchronous motor control circuit, thereby stopping the shear in the proper position to accelerate for the next cropping cut.

It will. thus be apparent that my invention adapts itself to a combination of controls as will readily be apparent.

From the foregoing it will also be apparent that the present invention provides means for always maintaining a shear speed proportional to the surface speed of the mill rolls through the medium of an electrical tie. provided means whereby the speed relationship may be changed at the will of the operator in case adjustment is required. The invention thus possesses the advantages of providing means for driving a flying shear in definite speed relation to the speed of a mill stand located in any desired relationship thereto with means for adjustingthe speed of the shear so that the lengths cut may be varied at will, while at the same There is also time maintaining a definite but adjustable speed relation of the character referred to.

The invention further possesses the advantage of providing means for establishing and maintaining a definite but adjustable speed relationship between the speed of a shear and the speed of any one of a number of stands in a continuous mill train. This implies means for driving a shear from any one of a number of individual mill stands, this being accomplished in the illustrated embodiment by the motors which drive such roll stands even though the gear ratio between the motors and the roll stands is different in different cases.

The invention also contemplates means for bringing up the rear end of a strip after it has left the last stand of a train of continuous mills and to maintain the same relation between the speed of the strip and the speed of the shear that previously existed while the strip was in the mill.

Other advantages result from the provision of means for readily adjusting the speed of the shear to a definite and adjustable but predetermined relation to the delivery speed of the strip while it is in the rolls even though the roll diameter be changed, for example by dressing the rolls to a smaller diameter, and by the provision of means for adjusting the speed of the shear to the required speed and maintaining it after the rear end of the strip has left the last stand of rolls even though the roll diameter be changed.

The provision of a scale or other indicator enables the desired adjustment to be expeditiously effected.

While I have herein illustrated and described a preferred embodiment of the present invention, it will be apparent that changes in the construction and operation of the parts may be made without departing either from the spirit of the invention or the scope of my broader claims.

I claim:

1. In a system of the character described, a roll stand, gearing for driving the rolls of said stand, a motor connected to said gearing, a generator of the alternating current synchronous type driven in predetermined speed relationship to the motor and mill rolls, a rotary shear, an alternating current motor of the synchronous type operatively connected to said shear through a hydraulic system, and means for establishing a circuit between said generator and said motor.

2. The combination with a continuous mill including a plurality of roll stands having rolls therein, of a rotary shear, and means for electrically synchronizing the shear speed to the speed of any stands of rolls, said means including a synchronous generator operatively connected to each roll stand and a synchronous motor adapted to be driven thereby, there being means for varying such synchronous speed relationship.

3. In a system of the character described, delivery rolls, pinch rolls and a shear, means for maintaining a predetermined speed relationship between both the pinch rolls and shear and the delivery rolls, and means for varying the speed relationship of either the pinch rolls or shear while maintaining a constant speed of roll delivery.

4. In a shear system, a plurality of mill stands, motors for driving the several stands, gearing connecting the motors with their respective stands, the gearing for the several stands being in difierent ratios, a flying shear, an electric motor determining the speed of the flying shear, generator systems connected to the several mill motors, and means for selectively connecting the shear motor to any desired one of the generator systems, said generator systems being of such character as to compensate for the difference in gear ratio between the several motors and their mill stands, and correspondingly adjust the speed of the shear.

5. In a shear system, a plurality of mill stands, motors for driving the several stands, gearing connecting the motors with their respective stands, the gearing for the several stands being in difierent ratios, a flying shear, an electric motor determining the speed of the flying shear, generator systems connected to the several mill motors, and means for selectively connecting the shear motor to any desired one of the generator systems, said generator systems having different numbers of poles to compensate for the difference in gear ratio between the several motors and their mill stands, and correspondingly adjust the speed of the shear.

6. In a metal working apparatus of the class described, a rolling mill stand, a rotary flying shear adapted to cut material delivered from said mill into predetermined lengths, a pinch roll stand disposed between said mill stand and said shear and adapted to positively feed said material to said shear, connected electrically operated means for driving said mill stand, said pinch .rolls, and said rotary shear at basic angular velocity ratios, avariable speed gear interposed between said electrically operated means and said pinch rolls, and another variable speed gear interposed between said electrically operated means and said rotary shear, means for actuating said first named variable speed gear to adjust the angular velocity relation between said mill stand and said pinch rolls whereby the peripheral or linear delivery speeds of the mill and of the pinch roll stand may be synchronized regardless of any difference in diameter of the rolls of said mill or of said pinch rolls, and means for actuating said second named variable speed gear to adjust the angular velocity relation between said mill stand and the rotary shear in order to determine the length of cut'to be effected upon said material.

7. The combination with a rolling mill, of auxiliary feeding means, a shear adapted to receive material from said mill or auxiliary feeding means, synchronous electrical means for driving the auxiliary feeding means and the shear at speeds proportional to that of the mill, and means for varying the relation between the speed of the mill and the speeds of the auxiliary feeding means and the'shear.

8. Apparatus for shearing metal strip to length comprising a pair of rolls adapted to feed the strip, a synchronous electric generator operatively connected to the rolls so as to run at a speed having at any one time a fixed relation to the speed of the rolls, a shear adapted to cut the advancing strip into lengths, a synchronous motor for driving the shear and electrical connections between the generator and the motor whereby the shear is driven in a desired speed relation with the rolls.

9. Apparatus for shearing metal strip to length comprising a pair of rolls adapted to feed the strip, means for driving the rolls, a synchronous electric generator driven with the rolls and at a speed corresponding to the speed thereof, a shear adapted to cut the advancing strip into lengths, a synchronous electric motor for driving the shear, and electrical connections between the generator and the motor whereby the shear is driven in a desired speed relation with the rolls.

10. Apparatus for shearing metal strip to length comprising a pair of rolls adapted to feed the strip, a synchronous electric generator operatively connected to the rolls, a shear adapted to cut the advancing strip into lengths, a synchronous electric motor for driving the shear, electrical connections between the generator and the motor whereby the shear is driven in a desired speed relation with the rolls through the electro-synchronous tie provided by the generator and the motor, and a speed changing device in the driving mechanism whereby the relationship between the speeds of the rolls and the shear may be varied.

11. Apparatus for shearing metal strip to length comprising a pair of rolls adapted to feed the strip, a synchronous electric generator operatively connected to the rolls so as to run at a speed having at any one time a fixed relation to the speed of the rolls, a rotary shear adapted to cut the advancing strip into lengths, a synchronous motor for driving the rotary shear and electrical connections between the generator and the motor whereby the shear is driven in a desired speed relation with the rolls.

12. Apparatus for shearing metal strip to length comprising a plurality of sets of rolls each adapted to feed the strip, a plurality of synchronous generators operatively connected one to each of the several sets of rolls so as to run at speeds related to the speeds of the rolls, a shear adapted to cut into lengths strip advanced from any of the several pairs of rolls, a synchronous electric motor for driving the shear,-and means for electrically connecting the motor with any of the synchronous generators as desired.

13. Apparatus for shearing. metal strip to length comprising a plurality of sets of rolls each adapted to feed the strip, a plurality of synchronous generators operatively connected one to each of the several sets of rolls so as to run at speeds related to the speeds of the rolls, a shear LORENZ IVERSEN.

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