US2900143A

US2900143A - Brake control for uncoiler

Info

Publication number: US2900143A
Application number: US457092A
Authority: US
Inventors: Kenneth L Bandy; Richard C Davidson
Original assignee: McKay Machine Co
Current assignee: McKay Machine Co
Priority date: 1954-09-20
Filing date: 1954-09-20
Publication date: 1959-08-18
Anticipated expiration: 1976-08-18

Description

K; BANDY ET AL 2,900,143 BRAKE CONTROL FOR UNCOILER Aug. 18, 1959 3 Sheets-Sheet 1 7 Filed Sept. 20, 1954 YIN BN1 0R5 HANDY ATTORNE Y Aug. 18, 1959 K. BANDY ET AL 2,900,143

BRAKE CONTROL FOR UNCOILER Filed Sept. 20, 1954 3 Sheets-Sheet 2 IN VENTORS KENNETH L. BANDY RICHARD C. DAVIDSON ATTORNEY v 3 Sheets-Sheet 3 "H hu mm oukzow Em u .\\\\wfi mm -mn h Aug. 18, 1959 K. BANDY ET AL BRAKE CONTROL FOR UNCOILER Filed Sept. 20, 1954 INVENTORS KENNETH 5mm RICHARD c. DAVIDSON BY W W ATTORNEY I E 2 z x .4 405.23

9. 1|||v 3E wk. #1 fl MM On a On 8 m on v 7 United States Patent BRAKE CONTROL FOR UNCOILER Kenneth L. Bandy, Canfield, and Richard C. Davidson, Youngstown, Ohio, assign'ors to The McKay Machine Company, Youngstown, Ohio, a corporation of Ohio Application September 20, 1954, Serial No. 457,092

'5 Claims. (01. 242-7544) feeding metal strip and in the provision of an improved control for such line of components whereby strip may be fed at a maximum rate of speed in highly accurate increments. The present invention contemplates the pro- In the drawing:

Figure 1 is a side elevation, partly in section, of a strip feeding line incorporating the teachings of our invention;

Figure 2 is a top plan wiew of the line of Figure l; and

Figure 3 is a simplified schematic representation of the control system incorporated in our improved strip feeding line.

Referring now to the drawing, the numeral 10 designates a conventional shear to which it is desired to feed predetermined increments of strip material. Of course, the shear 10 is merely a representative apparatus, as it is contemplated that the strip line may be employed in connection with presses, punches, or any other type of apparatus requiring an intermittent supply of material fed in measured increments. Adjacent the shear 10 is a conventional processing roller leveler and strip feeder 11 having a plurality of driven processing rolls 12' and power driven entry and exit pinch rolls 13 and 14 respectively. The various rolls 1214 are driven through a gear box 15 (Figure 2) by means of a heavy duty direct current drive motor 16.

In connectionwith the leveler and feeder 11 there is provided a measuring box 17 which is arranged to be driven by suitable accurately dimensioned measuring rolls, not specifically shown, in such manner as to register the linear extent of strip material passing through the vision of an improved arrangement for drawing metal is such that the high inertia of the coil is isolated from the device which feeds strip into the press or shear, so

that feeding device may be rapidly accelerated to a high speed and then rapidly decelerated and accurately stopped so that the increments of material are accurate and uniform at all times. 7

More specifically, the invention contemplates the provision of an improved strip feeding line comprising, in combination with .a press or shear apparatus, for example, a device for drawing strip from a coil thereof and feeding suchstrip to a looping pit, and a device for drawing such strip from the looping pit for direct feeding to the press or shear, the various line components having a novel integrated control system whereby strip is fed into the looping pit'in an improved manner and in accordance with the rate at which it is drawn out and fed to the press or shear. 7

Yet another object of the invention is the provision of an improved strip feeding line of the type described above, having separate means for drawing strip from a coil thereof, and feeding the strip to a press or shear, for example, wherein improved arrangements are provided for controlling the pay-off of strip from a coil thereof so that a certain back tension may be maintained between the coil and the means for drawing strip therefrom. Thus, it will be understood that in the high speed intermittent feeding of increments of strip the equipment is periodically accelerated and decelerated. If slack or looseness in the strip ispermitted between the coil and the means for drawing strip therefrom the strip may be broken when a feeding operation is initiated, or, at least the strip material and/or the line equipment may be seriously damaged. The apparatus of the present invention avoids this condition as will become apparent.

The above and other objects and advantages of the invention willbecome apparent upon full consideration of the following detailed specification and accompanying drawing wherein is shown a certain preferred embodiinent of the invention.

through the rolls 14 of an increment of strip material the measuring box 17 registers the quantity of material fed, causing the feeding equipment to slow down just before the final desired length is reached, and then causing the feeding to be discontinued at the exact point desired. This is accomplished through the use of switches which are arranged to be tripped in the measuring box as predetermined lengths or increments are'registered thereby.

To supply strip to the roller leveler 11 there is provided anuncoiler device 18, which may be of the type shown and described in co-pending application Ser. No. 429,239, filed May 12, 1954, by Kenneth L. Bandy, for Strip Uncoiler and Control Therefor, now U.S. Patent No. 2,800,- 288 and which is assigned to the assignee of the present invention. The uncoiler 18 is provided with oppositely disposed

spindles

19 and 20 having coil supporting cones 21 and 22 thereon which may be inserted into the eye of a coil 23 to support the same in the manner shown in Figure 1.

Positioned forwardly of the uncoiler 18 is a pay-off drive 24 comprising, in its barest essentials, a pair of power driven pinch rolls 25 and a direct current drive motor 26 and transmission 27 therefor. Depending upon the nature of the material to be handled, the character of the operation to be performed, and upon various other considerations, the pay-01f drive 24 may be combined with such other apparatus as strip cleaning and processing mechanisms, aswill be readily understood. However, for the purpose of thepresent invention such ancillary apparatus need not be considered; 7

Between the pay-off drive 24 and the processing leveler and feeder 11' 'there is provided a loop pit 28 having a plurality of sets'of photoelectric cells 29-32 which are r located at one side' ofthe pit directly opposite a like plurality of light sources 2932'. As will be hereafter more fully described the photoelectric cells are employed for controlling or regulating the operation of the

drive motors

16 and 26 in such manner that strip material is drawn oif of the coil 23 at an average relation to the rate at which the strip is fed to the press 10.

Having reference now to Figure 3 of the drawing-it will be observed that the pay-oil? and

feed drive motors

26 and 16 are provided with separate drive controls indicated schematically and represented by the reference numerals 33and 34 respectively. The drive control for the pay-off apparatus may be a more or less conventional variable speed system of the type known generally as the Ward-Leonard system which, in its commercial embodiment may be a Reliance V S system incorporating an electronic regulating panel operating through a motor-generator system to feed direct current to the motor 26. Such an arrangement is schematically indicated at 60 in Figure 3. A similar Reliance V S system may be employed in connection with the feeder drive motor 16. However, the separate control systems will have different control stages and adjustments to suit the differing requirements of each.

In accordance with the teachings of the present invention the panel 33 is arranged to energize the pay-ofi drive motor 26 at various speeds, up to a maximum speed which results in the paying off of strip at a rate of approximately 220 feet per minute. Actually, the control is such that when a loop 35 breaks the light beam from the top source 29, but is above the light beam from the second source 30', the motor 26 will be accelerated toward its maximum speed. When the second light beam is broken further acceleration is discontinued and the motor 26 continues to feed strip into the pit at high speed. When the third light beam, from source 31, is broken the motor 26 is decelerated to a slower speed and feeding continues at this rate until the bottom light beam, from source 32', is broken, whereupon the drive motor 26 is dynamically braked to a stop.

The above control procedure is, of course, effected by directing the photoelectric responses of cells 2932 into the pay-ofi drive control 33.

Prior to a feeding operation the loop 35 will be at the bottom of the pit 28 so that the loop intercepts the lowermost beam from the source 32. A feeding operation is initiated by any suitable means, and thereupon the feeder drive motor 16 accelerates to a maximum speed, corre sponding to a rate of feed of approximately 320 feet per minute. The period of acceleration is about 0.4.second. The loop 35 will of course be pulled upwardly, and as the lower light beam is cleared the motor 16 accelerates to its slow speed level, which slow speed level is maintained after the loop clears the next light beam from source 31'. At this point the rate of feed is substantially in excess of the slow speed rate of pay-off and the loop 35 continues to move upwardly until the next succeeding light beam, from source 30', is broken, at which time the pay-off drive motor will accelerate, and will continue to accelerate, up to its maximum speed, until the loop moves downwardly to again intercept the second light beam. At this point the pay-01f drive motor will maintain its high rate of feed, unless and until the loop intercepts the third light beam.

As will be readily understood, in continuous repetitive feeding operations it will be possible to so adjust the control circuit for the pay-off drive motor 26' that the loop will be maintained between the second and third light beams.

It will be observed, of course, that while the rate of feeding is considerably in excess of the maximum rate of pay-01f of the strip the pay-ofi drive can readily maintain the same average rate of strip movement as there is a period of from one to two seconds in which [the feeder decelerates and stops and the shear is actuated.

However, in the event that there is a failure in the pay-off system so that the loop 35' is caused to move upwardly to the extent that it clears the upper light beam a signal is directed to the feed control 34 which results in emergency dynamic braking of the feeder drive motor 16. Possible serious damage to the feeder and pay-off equipment is thus avoided.

In accordance with the teachings of the invention there is provided in connection with the uncoiler 18 a novel braking system which operates in response to stimuli from the pay-off control 33 to effect a desired control over pay-off of strip from the coil 23. Thus, the spindle 19 of the uncoiler is provided at one end thereof with a brake 36 operated by means of an air cylinder 37, as shown schematically in Figure 3. Connecting the air cylinder is a conduit 38 leading to'separate valves 39, having an operating coil 39', and 40. Valve 39 has a normally closed passage communicating through a pressure regulator 41 with a source of air pressure 42. Valve 40, on the other hand, has a normally open passage communicating through a check valve 43 and pressure regulator 44 with the source 42.

Pressure regulator 44 is set for a relatively low pressure, which, since the valve 40 is normally open from the pressure regulator 44 to conduit 38, is normally applied to the head end of the brake operating cylinder 37 so that a low braking pressure is normally maintained upon the spindle 19.

As set forth in the before mentioned Bandy application Ser. No. 429,239, relating to the uncoiler 18, a coil 23 is supported thereon by moving the cones 21 and 22 into the eye of the coil and maintaining a predetermined clamping pressure between the cones to grip the coil firmly at all times. Thus, the coil 23, which is otherwise freely rotatable, is frictionally retarded somewhat through the brake 36, the arrangement being such that a slight back tension is maintained upon the strip as the same is drawn off the coil by the pinch rolls. This keeps the strip taut during uncoiling and avoids any tendency of the coil to rotate faster than the rate at which strip is drawn from the periphery thereof.

Coil 23, of course, has substantial momentum or inertia when rotating at full speed so that when the pay-off drive motor 26 is slowed or stopped in accordance with the position of the loop 35 it is necessary to apply a stopping force to the coil, to prevent unwinding of the strip therefrom. Accordingly, the pressure regulator 41 is set for high pressure, so that when valve 39 is energized high pressure fluid moves into the brake cylinder actuating system causing a high braking force to be applied to the coil 23 through the brake 36 and spindle 19. Thus, in accordance with the teachings of the invention, the operating coil 39 for valve 39 is connected to the pay-off drive control in such manner as to be actuated whenever the speed of the pay-off drive motor 26 is decreased, so that high braking pressure is applied and the coil 23 is quickly slowed down to maintain tautness in the strip. In the illustrated control arrangement the valve 40 will remain deenergized during times when the valve 39' is energized. However, the high pressure fluid cannot escape due to the check valve 43. It is contemplated, moreover, that the valve 40 will remain deenergized at all times except when a new coil is loaded onto the uncoiling apparatus and the strip is threaded through the associated pay-off and feeding, apparatus. During such times the presence of any braking pressure upon the coil would be undesirable. Therefore, upon energization of valve 40, valve 3? being deenergized, the cylinder will be open to exhaust, through conduit 46, so that all pressure is relieved therefrom. I

In order to permit the escape of high pressure fluid from the system after valve 39 is deenergized a relief valve 45 is provided which bleeds oil the excess fluid until the system is substantially at the pressure at which relief valve 45 is adjusted. I

During normal operation, the feeder drive'motor 16 is energized periodically, by means of a limit switch on the shear 10, for example, which causes strip to be drawn out of the looping pin 28 at high speed. As the light beams within the pit are successively uncovered the pay-01f drive motor is caused to accelerate. Eventually the loop will move up over the light beam from the light source 30 and then back down to cover up this same beam. At this point the motor 26 runs at a constant speed, and it is possible to so adjust the control components that this speed will be the average speed at which strip is fed to the press 10. In this manner the loop 35 may be caused to move up and down between the second and third light beams from sources 30 and 31' respectively.

In the Reliance V*S system this manner of control is effected through the use of a motoroperated control rheostat 50-51 which is actuated in response to the photoelectric signals from the looping pit 28. Thus, when the cell 30 receives a light beam the rheostat 50 moves at a predetermined rate toward positions in which the motor 26 will operate at higher speed, thereby causing the motor 26 to continuously accelerate. When, at a subsequent time, the loop 35 moves downwardly again, and the cell 30 receives no light, the motor operated rheostat is stopped so that the motor 26 remains operating at a preset high speed. If all adjustments are correct at this point the loop will hover between the second and third light beams. However, if the pay-off speed is higher than the average feeding speed the loop will eventually cross the third light beam, at which point the motor operated rheostat 50-51 is energized to move in a motorslowing direction, and will continue to so move until the third beam is again uncovered, at which time the motor operated rheostat will hold its then existing position and the pay-01f motor 26 will operate at a continuous but slower speed.

In each case, when the motor operated rheostat operates in a motor-slowing direction, the operating coil 39' for valve 39 is energized through control apparatus generally indicated at 61 in Figure 3 of the drawing so that high braking pressure is applied to the coil 23 to decelerate the same and maintain a back tension on the strip. Then, when the rheostat is stopped or moved in a motorspeeding direction the coil 39 is deenergized and the high pressure is bled off through relief valve 45 so that the normal minimum braking pressure is restored to the coil so that the strip may be freely uncoiled with a slight back tension.

Of course the feeder drive motor 16 is controlled wholly independently of the pay-off drive motor, except in emergency cases when the pay-off system fails to function properly and the uppermost light beam is cleared. In this event the feeder drive motor is braked to a rapid stop at any point in the feed cycle. In all other cases the feeder motor 16 is controlled by the shear and the measuring box 17, in accordance with preferred practice.

It should now be apparent that we have carried out the several objects of our invention as before set forth. Our strip feeding system, while not new in any broad sense, incorporates a number of novel specific features which render the system suitable for feeding strip at extremely high rates of speed, as compared to heretofore known systems. Thus, whereas with prior systems of which we are aware it has been impossible or impractical to exceed feeding speeds of in excess of two hundred feet per minute, with our apparatus speeds of up to three hundred twenty feet per minute are readily obtainable.

One of the advantageous-features of our invention is our novel combining of a photo-electric loop control with a variable speed motor drive so that strip may be fed to a loop pit at a rate of speed which accurately corresponds to the average rate at which strip is fed to the press or other allied apparatus. Of course, neither the photo-electric loop control or the variable speed pay-off motor control are in themselves new. However, the invention in this case resides in a unique manner in which photo-electric stimuli from the loop control are applied to the variable speed motor system. Our system" is best adapted for intermittent feed operations wherein a regular average rate of feed is established, and in such cases it is an easy matter for the line operator to so adjust the motor control system that substantially continuous speed operation is realized in the pay-off section of the strip line.

Another important feature of the invention resides in our novel coil braking system whereby an unwinding coil is maintained under a predetermined minimum retarding pressure to maintain a certain back tension in the strip. In this manner jerking and buckling of the strip is avoided. In addition, our coil braking system includes means operative automatically upon deceleration of the pay-off drive motor to increase the coil retarding force so that the inertia-laden rotating coil does not overrun the pay-off mechanism. This is very important in a high speed system as will be readily apparent; for otherwise the strip would slacken when the pay-off drive motorvwas decelerated to aslower speed. In such cases, when the motor was again accelerated to a high speed the strip would be snapped taut with considerable force, causing damage to the strip and/ or the line apparatus.

It should be understood, however, that the embodiment herein shown and specifically described is intended to be representative only, and reference should therefore be had to the following appended claims in determining the true scope of the invention.

We claim:

1. In a strip feeding line of the type adapted for intermittent feeding of measured lengths of strip material, and of the type having an uncoiler, a pay-off device associated with said uncoiler and having variable drive means and control means for causing said drive means to accelerate and decelerate, said uncoiler being of the type having means to firmly grip a coil of strip material and to automatically apply frictional braking pressure thereto; the improvement in said last mentioned means comprising a fluid cylinder, a fluid system leading to said cylinder and including a source of fluid under pressure, a first valve in said fluid system having a normally open passage leading to said cylinder and communicating between said passage and said source with a pressure reducing valve having a relatively low pressure outlet, a second valve in said fluid system having a normally closed passage leading to said cylinder and communicating between said passage and said source with a pressure reducing valve having a relatively high pressure outlet, and means to actuate said second valve to open said last mentioned passage when said drive means is decelerating.

2. In a strip feeding line of the type adapted for intermittent feeding of measured lengths of strip material, and of the type having an uncoiler, a pay-off device associated with said uncoiler and having a drive motor and control therefor, a looping pit on the exit of said pay-off device, and a high speed feeder device positioned on the exit side of said pit; the improvement in the control for said motor which comprises a plurality of strip position detecting devices located in said looping pit and defining a zone, first means included in said control system responsive to a loop of material moving above said Zone to cause said motor to accelerate, second means included in said control system responsive to said loop moving below said Zone to cause said motor to decelerate, and third means included in said control system responsive to said loop being positioned in said zone to cause said motor to maintain the speed at which said motor was operating when said loop entered said zone, further including means to .brake'the rotation of a coil supported on said uncoiler;

said means including means to normally apply a low pressure frictional braking force and means operative when said motor is decelerating to apply a high pressure frictional braking force whereby said coil may be quickly brought to a complete stop.

3. In a strip feeding line of the type adapted for interof the type having an uncoiler, a pay-off device associated with said uncoiler and having variable drive means and control means for causing the said drive means to accelerate and decelerate, said uncoiler being of the type having means to firmly grip a coil of strip material and to apply frictional braking pressure thereto; the improvement in said control means and in said last mentioned means comprising a motor-operated rheostat movable in motor-slowing and motor-speeding directions whereby to cause said drive means to decelerate and accelerate, automatically applied fluid coupling means to vary the frictional braking pressure applied to said coil, said means to vary the braking pressure including means to maintain a normally light frictional braking pressure upon said coil and means to increase said pressure when said motor operated rheostat moves in a motor-slowing direction whereby said coil may be brought quickly to a complete stop, said fluid coupling means to apply braking pressure comprising a fluid cylinder and a source of fluid under pressure, and said means to vary the braking pressure comprising solenoid operated valve means operative to selectively apply higher and lower fluid pressure to said cylinder.

4. Apparatus according to claim 3 further characterized in that said valve means comprises a solenoid valve adapted to be energized when said rheostat is moved in a motor-slowing direction whereby to cause the application of said higher pressure to said cylinder.

5. In a strip feeding line of the type adapted for the intermittent feeding of measured lengths of strip material, an uncoiler, strip storage means positioned forwardly of said uncoiler in the direction of strip travel for receiving strip, said uncoiler being of the type having means to firmly grip a coil of strip material and to apply braking pressure thereto, said means to apply braking pressure comprising a fluid cylinder, a fluid system leading to said cylinder including a source of fluid pressure, means to vary the braking pressure including means to maintain a normally light braking pressure upon said coil and means to increase said braking pressure to apply a high braking force, said means to vary the braking pressure comprising valve means in said fluid system for alternately applying higher and lower fluid pressures to said cylinder, said valve means being operative in response to the quantity of strip in said strip storage means, said valve means comprising a first valve in said fluid system having a normally open passage leading to said cylinder and communicating between said passage and said source with a pressure reducing valve having a relatively low pressure outlet, a second valve in said fluid system having a normally closed passage leading to said cylinder and communicating between said passage and said source with a pressure reducing valve having a relatively high pressure outlet, and means to actuate said second valve to open said last mentioned passage in response to the quantity of strip in said strip storage means.

References Cited in the file of this patent UNITED STATES PATENTS 1,265,328 Henderson May 7, 1918 1,286,331 James Dec. 3, 1918 2,147,421 Bendz Feb. 14, 1939 2,462,558 Scheuermann et al Feb. 22, 1949 2,599,795 White June 10, 1952 2,636,693 Littell et al. Apr. 28, 1953