US1894815A - Control system - Google Patents

Description

Jan. 17, 1933. F. c. BIGGERT. JR, ET AL 1,894,815

CONTROL SYSTEM Filed June l6, 1930 4 Sheets-Sheet 1 F" 1. 29 9 22 g 29 "I '1 21 11 o i: o o 1"! o 0 I :I

. oi o Zmon I gm Jan. 17, 1933.

F. C. BIGGERT, JR., ET AL CONTROL SYSTEM Filed June 16, 1930 4 Sheets-Sheet 2 INVENTOR TC? L -W L I I F m u n a j 4 i u m h HuT-----i---i-: u r \d 1 L mfi g @T l vv RN Q .1 WW WM. mm. \W N NH Jan. 17, 1933. F. c. BIGGERT, JR., ET AL 1,394,315

4 CONTROL SYSTEM Filed June 16. 1930 4 Sheets-Sheet 3 INVENTOR WITNESSES fill/51M 4% 5 m 16.11.17, 1933. F. c. BIGGERT, JR., ET AL 1,394,815

CONTROL SYSTEM I I Filed June 16, 1950 4 Sheets-Sheet 4 INVENTOR 44' M/QMZ/ Za'ae M Patented Jan. 17, 1933 .U-NITED STATES PATENT OFFICE FLORENCE G. BIGGEBT, J'B., OF GRAFTON, AND JOHN A. SMITMANS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS 'IO UNITED ENGINEERING &FOUNDBY COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA CONTBOL EYSTEE Application filed June 18,

flying cutter for severing moving material,

such, for instance, as metal strip or the like coming from a rolling mill, which is capable of cutting the strip into any desired lengths, and of operating on. any such material during its movement, at any desired point.

The primary object of this invention is to provide a control system for automatically controlling the operation of a flying cutter of the above noted. character or moving element of that nature,

Various other objects, as well as the novel features and advantages of the invention, will become more apparent when the followin detailed description is read in conjunctlon wlth the accompanying drawings, in which,

Fig. 1 is an end View of a flying cutter of the type contemplated, as seen in the direction of movement of the material, in this instance the strip issuing from the rolling mill;

Fig. 2- is a side elevation of the same, the cutting blade being shown in the stationary position it occupies when not in operation;

Fig. 3 is a diagrammatic side view, showing the blade, in full lines, in its cutting position, the stationary position of the blade being shown in dotted lines;

Fig. l isa similar view showing the blade at a position such as it assumes when about to reverse its direction of movement to return towards'its normal stationary position;

' ing a single embodiment of the invention adapted for controlling the operation of a blade-actuating electric motor for obtaining the desired movement of the blade, the circuit, and the control apparatus therein, being shown in its normal deenergized condition;

1930. S'erlal No. 461,828.

and'Fig. 7 is a full line wiring diagram of the control systems shown in Fig. 6.

Referring now to the drawings,.the particular form of flying cutter selected for illustration and shown therein is intended for cutting strip as it'issues from a rolling mill, and comprises an anvil roll 10 rotatably mounted in bearings carried by a stand 11 and driven, through suitable .reduction gear- -ing 12, at a peripheral speed which is substantially the same as the linear speed of the strip, by means of an electric motor 13, hereinafter referred to as the anvil motor. It will beappreciated that the linear speed of the strip, generally referred to as the mill speed, will vary with difierentjobs. Accordingly, means of a well known character are propided for running the anvil motor 13 at varying speeds, to accord with the mill :peed which may obtain at that particular line.

For cutting the strip when desired a blade 14 s provided, which is adapted to work against the anvil roll 10 and make cutting engagement with the strip as the latter passes above such anvil roll. The blade is mounted in a blade holder 15 which is secured to a shaft 16 rotatably mounted in bearings carmed by the stand 11. The shaft 16 is adapted to be rotated in a clockwise direction, as seen in the side views (it being understood that the strip enters the device from the right), by an electric motor 17, hereinafter referred to as'the blade motor, The blade is thus rotated, from the stationary position shown in Fig. 1, through more than a complete revolution, during which movement it makes the cut, and is then caused to rotate in a reverse direction until it regains its original stationary position.

To determine the normal stationary position of the blade, the following means are employed in the particular device shown:

The base of the blade holder 15, or other adapted to en collar 23 whic the inner surface of a is fixedly mounted on the stand 11, concentric with the blade holder;

shaft 16. The lever 21.is provided with a manually operable latch 24 adapted to en-- gage in one or another ofa series of teeth 25 0 rmed onthe outer periphery of the collar 23, so that the position of the lever, and con "well known drum type, is connected to rotate with the blade holder shaft 16, and eflects the starting and certain of" the other manipulations of the blade-motor 17. When the strip is to'be cut, an electrical contact is made, either manually, or automatically, to cause current to be supplied to the blade motor to cause the latter to rotate in a forward direction. The blade motor, and the resistances, etc. in its circuits, is so constituted that by the time the blade has rotated from its stationary position, shown in Fig. 2,; to its cutting position shown in Fig. 3 it will have been accelerated to just that extent that the peripheral speed of its edge will be substantially the same as the linear speed of the ma terial. That this condition may continue to obtain, in spite of the fact that the mill speed may vary, we provide control means between the anvil motor 13 and the blade motor 17 so that the speed of the blade motor, at least during the forward accelerating portion of its cycle of operation, willbe dependent upon the speed of the anvil motor and consequent ly upon the mill'speed.

It will be observed that the periphera speed to" which the blade 14 is accelerated will be dependent upon the length of the circular path through which it moves to reach the cutting position; so that the peripheral speed of the blade, at the cutting instant, can be controlled by modifyin the original stationary osition of the blade. This can be effected y shifting the dog 20, through an adjustment of the lever 21.

ubstantially when the cut occurs, the

limit switch 26 operates to break the circuit supplying current to the blade motor 17, and,

slightly later, operates to establish a circuit supplying current to such motor in a reverse direction. However, owing to the momentum of the blade and blade-holder, the motor armature, etc., these parts continue to rotate in a. clockwise direction,'against the braking eflectof the reversed motor current, until is reached as is indicated in Fig. 5, whereupon the motor circuit is broken. Thereafter, by reason of the weight of the bladehdlder 15 and associated members, the parts settle in a counter-clockwise direction until the-shoulder 19 again rests on the dog 20.

The parts are then in position for another out.

In order' to indicate adjustments which may be desirable in operation, such as an adjustment of the position of the dog 20, we provide means by which the peripheral speed of the blade, at the cutting instant, may be read. If such peripheral speed does not accord with the mill speed, the dog 20, for in-- stance, may be adjusted to cure the defect. One such means conveniently consists of a fly wheel 27 having a driving connection with the blade holder shaft 16 so as to rotate with the latter, such fly wheel having a ratchetconnection with its shaft, so as to be driven in one direction only. Thus the fly wheel 27 will be accelerated up to the hi hest speed of the blade holder which is reac ed at substantially the cuttln instant), and will thereafter rotate at su stant-ially such speed for a short time, suflicient to enable a reading to be taken, ofits own momentum. The

fly wheel 27 may take the form of a gear with which meshes a pinion 28 on the shaft of a magneto 29 furnished with anindicator 30. From this indicator the peripheral speed of the blade, at the cutting instant, can be read and any desirable ad ustments accordin 1y made. I

n Fig. 6 of the drawings we have illustrated one embodiment of the invention which is adapted to control the operation of the blade motor in the manner above referred to. As illustrated in this figure the armature 101 of motor 17 is connected, in series relation with its series field winding 102 and a plurality of resistor sections 103, 104 and 105, across lines 106 and 107 which are in turnconnected to a source of current supply 111. In parallel relation with this circuit is another circuit including a shunt field winding 112 for the motor.

For establishing the circuit of the armature 101, and controlling the direction of flow of current therethroug'h so that the motor may be actuated in either direction, a pair of forward switches 113 and 115, and a pair of reverse switches 114 and 116 are provided. To provide automatically for controlling the operation of these and other switches in the system, a drum limit switch 26' is employed, and, as referred to hereinbefore, is operably 0011 )led for rotation with the motor. Such limit switch comprises a pair of continuous supply bands 118 and 119 and three shorter bands 121, 122 and123, of which the bands 118 and 121 are connected together, as also are the bands 119, 122 and 123. A line of brushes 118a, 119a, 121a, 122a, and 123a are adapted to make contact with the correspondingly numbered hands, the relative positions of the bands and brushes, in the normal deenergized condition of the system, being indicated by the line a in the diagram in the lower left hand corner, in which the bands are shown in development.

A push button 124, normally occupying the upper position shown in the diagram, is shown as the means for starting the operation of the system. The contact 124a of th's button, when depressed. establishes a circuit extending from line 106 through the actuatin coil 125a of a low voltage relay 125'to line 107. The low voltage relay has a holding contact 12575, adapted to establish a holding circuit through the coil 125a after he re lay has once been actuated, a contact 1250, adapted to establishconnection between the line 106 and supply band 118, throughthe brush 1180:, when the relay is actuated, and a back contact 12501 adapted to establish connection between the line 106 and the supply \band 119, through the brush 1190:, when the relay is released. Thus when the low voltage relay 125 is actuated. upon the push button 124 being depressed, the brush 118a'and supply band 118 are connected to the line 106, the brush 119a and supply band 119 are d sconnected from the line 106, and a holding circuit is established which maintains the relay closed in spite of the subsequent release of the push button. This holding circuit is traced from line conductor 106 through interlock 1250, brush 118a. supply bands 118 and 121 of switch 26, brush 121a, contact 125?) and thence through coil 1250; to line conductor 107.

Upon the push button 124 being released after actuation, its contact 124a throws into operation a forward relay 128 which establishes a holding circuit for itself and also throws into operation the forward switches 113 and 11.5 to cause the blade motor to rotate in the forward direction. The circuit for is from the brush 118a. through the raised push-button contact 124a, forward relay ac' tuating coil 128a and back contact 1140 (to be hereinafter referred to) to the line 107. Theholding circuit is from the line 106 through a holding contact 128?; of the forward relay, the actuating coil of such relay .ed in series with the motor;

band 118 through theband 121, brush 121a, the contact 1280 of the forward relay 128 and the actuating coils 113a and 115a, respectively, of the forward switches 113 and 115, to the line 107.

From the foregoing it will be seen that upon the push button 124 being depressed and subsequently released, the circuit for r0 tating the armature 101 ofblade motor 17 will be established, and will be maintained until broken at a later period as hereinafter explained. The motor 17 is adapted to rotate the blade-holder 15 towards cutting position, and accelerate such blade holder so that the blade reaches face speed with the strip by the time the cutting position is reached.

To provide for variation of the speed of the blade motor in accordance with variations of the mill speed, so that the acceleration of the blade up to face speed with the strip may" be maintained in spite of such changes in the mill speed, we provide means, controlled by the speed of the strip, for cutting in or out sections of a resistance connect To this end, two (though more may be employed if it be desired that the control be more delicate) speed controlled switches 129 and 131, are connected, in parallel relation, between the brush 118a and the line 107. These switches have in their circuits the actuating coils 132a and 133a of switches 132 and 133, adapted, when closed, to establish shunt circuits around the resistor section 103 and the resistor sections 103 and 104, respectively, these resistor sections being connection in series with the motor. The switches 129 and 131 may be governor controlled, as indicated, or may be controlled by current conditions existing in other electrical circuits employed in the use of the cutter,as, for instance, in the field circuit of the anvil motor 13. They are responsive to the mill speed, and each to a different degree thereof. Suppose, for exam Ie, the mill speed is relatively low, the switc es 129 and 131 will remain open, leaving the resistor sections 103 and 104 effective. When the mill speed'is increased somewhat, the switch 129 will close, shunting the resistor section 103 and cons uentl speeding up the motor 17'. When t e mil speed is increased further, the switch 131 will close, shunting the resistor sections 103 and 104 and further increasing the speed of the motor 17 By the time the blade has reached the cutting position, the limit switch willv have moved, in the direction of the arrow shown at the top thereof in Fig. 6, to such a. position that'the line of contact of the bands with the. brushes will be at b. When this position is reached, the end of the band 121 asses from beneath the brush 121a, thereby reaking the holding circuits of the forward the blade to its starting position, the drum 7 thereby broken, the motor and blade-holder continue to rotate, of their momentum, until the} and the limit switch have slightly assed their original position and have reache a position, in the second rotation, where the relation to the bands to the brushes is as indicated by the broken line a. At this point, the.

band 123 comes into contact with its brush 123a, between which latter and the line 107 the actuating coils 114a and 116a of the reverse switches 114 and 116 are connected. Thus a circuit is established from line 106 through the back contact 125d (now closed) of the low voltage relay,'brush 119a, supply band 119, band 123, brush 123a and actuating coils 114a and 116a, to line 107. Thereby the reverse switches 114 and 116 are closed and current is applied to the motor in a reversed direction. So that a full "plugging current may be applied to the motor at this time, a shunt circuit is provided around the whole resistor comprised by the sections 103,

104 and 105, such shunt circuit having therein a normally open switch 135. The actuating coil 135a of such switch is connected, through a contact 1266 of another switch 126, to be hereinafter referred to, between the brush 119a and the line 107 so that when the back contact 12501, of the low voltage relay is closed and the contact 1266 is closed (as the latter is at this period in the cycle), the actuating coil 135a will be energized and the shunt circuit established around the resistor sections 103, 104 and 105. A powerful plugging current is thus applied to the motor, having the "effect of bra mg the rotating parts and finally bringing them to rest at a position of 'the blade holder which may be as shown in Fig. 4', the relative positions of the bands'and brushes of the limit switchbeing then as indicated by the broken line (I in Fig. 6.

fter the motor has come to rest the reversed current starts it backward, to return switch then rotating in the direction indicated by the arrow at the bottom of the limit switch ((Fig. 6). That the motor may not operate too rapidly in starting this reverse movement, the resistor sections 103, 104 and 105 are out in again substantially at the instant of physical reversal, and a shunt circuit, including a suitable resistor 137, is established across the motor armature. These results are effected by switch 126 which has an actuating coil 126a and a holding coil 1260. The actuating coil 12611 is inv circuit relation with the contact 1256 of the low voltage re-' lag, and thus is energized, to raise the switch, wen such relay is first o erated. The holding coil 1260, with a suita le resistance 134, is connected in shunt with the motor armature. Thus after the actuating coil 126a has been deenergized, due to the opening of the low voltage relay at the time the cut is made, the holding coil 126a, remains still energized by the counter-electromotive force of the armature, so that the switch 126 continues to be held in its raised position, with its contact 1266 closed and its back contact 126d 0 en. At about the point of physical reversal o the motor, however, the counter-electromotive force of the armature having dropped, the

drops, opening its contact 1266 and closing its back contact 12611. Opening the contact 1266 breaks the circuit in which is the actuating coil 135a of the switch 135; so that the switch 135 opens, cutting-in again to the motor circuit the resistor sections 103, 104 and 105. Closing the back contact 126d completes a circuit in which is the actuating coil 136a of a switch 136, which, when actuated, establishes a shunt circuit, including a resistor 137, around the motor armature 101. Thus, durin movement, w en the blade-holder 15 is being rocked back, for instance, past its up er dead center, the motor is operated slowly, but with suflicient power to effect the desired movementof the blade holder.

When themotor has made the initial part of its return movement, the armature 101 is short circuited, so as to brake the return movement of the. blade-holder, in which movement gravity now takes part. Such short circuiting of the armature occurs upon the right hand end of the band, 122 the brush 122a, whereupon a circuit is established-through the actuating coil 138av of a switch 138 which, when actuated, establishes a short circuit around the armature 101.

initial position, the left hand end of the band 123 leaves the brush 123a, thereby de-' ener izing the reverse switches 114 and 116 and bringing all circuits back to the normal deenergized condition shown in Fig. 6.

From the foregoing it will be appreciated; that-by means of such a system of control itis possible to operate a flying cutter of the nature described in such a way as to cut a moving strip at substantially an oint desired, entirely independently o t e circle which is described by-the blade edge. Thus the material may be cutinto len hs of any desired nicety of dimension. 11 that is necessary is toclose the blade-motor circuitmaking contact at such a time that the blade will reach the material at the point where it is desired that the cut shall be made. Furthermore, with such a system of control the the first part of the return reaching Just before the blade-holder reaches its cutter is well adapted for operation on material moving at a high rate of speed such as frequently obtains mrolling mill ractice, particularly where, as in the sizoveescribed form of the device, the blade has the greater part of an entire revolution in which to pick up to the linear speed of the material, and over a half revolution in which to be slowed down and stopped. Because of the control of the blade motor so that its s eed of operation, in rotating the blade to eiibct the cut, is dependent on the speed of the anvil motor, and thus corresponds with the mill s eed, the cutter automatically adapts itse f to difierent mill speeds.

While we have illustrated and described but a single control system embodyin our invention, it is to be understood that t e invention may be embodied in other forms, and that changes may be made in the form described and shown without exceeding the scope thereof, as defined in the appended claims.

I claim:

1. The combination with a rotatably mounted element, a movable element coo crating therewith, an electric motor operab y coupled to said rotatabl mounted element, and a source of current or said motor, of a control system for said motor, comprising a resistor element connected in circuit rela tion with said motor, means for short circuitm said resistor element each time said rotatab y mounted element is rotated a complete revolution and at a definite point in its cycle of rotation, speed responsive means associated with said movable element for controlling the operation of said short circuiting means, means actuated by said motor for automatically braking it by reversin the current thereto at a redetermined point in the path of travel of the rotatable element, and means for automatically stoppi said motor when said rotatable element 1s returned .to its starting position after the current is reversed.

2. The combination with a rotatably mounted element, an electric motor operably coupled thereto a movable element cooperating with said first-named element, and a source of current for said motor, ofa control system for said motor, comprising a resistor element connected in circuit relation with said motor, means for short circuiting said resistor element, speed responsive means associated with said movable element for controlling theoperation of said short circuiting means, means actuated by said motor for automatically reversing the current thereto at a predetermined point in the path of travel of the rotatable element, a second resistor element, means for automatically inserting said second-named resistor element in the motor circuit when the physical reversal of said motor takes place after the current thereto is reversed, and means for automatically stopping said motor when said rotatable element is returned to its starting position after being reversed.

3. The combination with a rotatable element, an electric motor having an armature operably coupled to said element, and a source of current for actuating said motor, of a control system for controlling the operation of said motor, comprising a starting switch for connecting said motor to said source of current, means actuated in accordance with the movement of said element for reversing the current through said motor at a predetermined point in the path of travel of the element, a resistor element, means for connecting said resistor element across said armature when the counter electromotive force in the armature fails after the current therethrough is reversed, and means for disconnecting the motor from the source of current when the rotatable element is returned to its starting position after the current therein is reversed. q

4. The combination with a rotatable el e-' ment, an electric motorhaving an armature operably coupled to said element, and a source of current for actuating said motor of a control system for controlling the operation of the motor comprising a startin switch for connecting the motor to sai source of current, a'drum switch actuated in accordance with said element, meansactw ated by said drum switch for reversing the current in said motor when said element passes a predetermined point in its path of travel, a resistor element connected in circuit relation with said armature, means actuated by said drum switch for short circuiting said resistor element when said current is reversed, a second resistor element, means for connecting said latter element across said armature when the counter E. M. F. in the motor fails after the current therein is reversed, and means actuated by said drum switch for disconnecting said motor from said source of current when said rotatable element is returned to its starting position.

5. The combination with a constantly driven rotary element a second rotatably mounted element, an electric motor operably coupled to said latter element, and a source of current for actuating said motor, of a system for controlling the operation of said mo tor, a starting switch for connecting said motor to said source of current for rotation in a given direction, a resistor element connected in said motor circuit for limiting the current thereto, speed responsive means actuated in accordance with the speed of said constantly driven rotary element for cutting out portions of said resistor to vary the spec of said second rotatably mounted element in accordance with that of the constantly driven element, means actuated by said motor for 6' I restart reversing the current through it at a predetermined point in the path of travel of said second rotatably mounted element, and means for automatically stopping said mo- 5 tor when the second rotatably mounted element is returned to its starting position. 6. The combination with a constantly driven rotary element a second rotatably mounted element, an electric motor having 10 an armature operably coupled to said second rotatably mounted element, and a source of current for actuating said motor of a control system for controlling the operation of said motor, comprising a starting switch for connecting said motor to said source of current for rotation in a predetermined direction, a resistor element connected in circuit relation with said armature for'limiting the 20 current therein, means automatically actuated in accordance with'the speed ofsaid constantly driven rotary element for cutting out portions of said resistor to vary the speed of said motor in accordance therewith, a drum switch coupled to said second rotary element, means actuated by said drum switch for reversing the current in said motor at a predetermined point in the travel of said second rotary element, other means actuated by said switch for short circuiting said resistor element when said current is reversed, a second resistor element, means for connecting said latter element across said armature when the counter E. M. F. in the motor fails after the current is reversed, and means actuated by said drum switch for opening the motor circuit when said second rotary element. is returned to its starting position after the current reversal takes place. I

In testimony whereof, we hereunto sign our names. I

FLORENCE C. BIGGERT, JR. JOHN A. sm'rmns.

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