US1946281A - Control system - Google Patents

Description

Feb. 5, 1934. v A, HEPPERLEN 1,946,281

CONTROL SYSTEM Filed March 31, 1930 Figl. I

Patented Feb. 6, 1934 PATENT OFFICE CONTROL SYSTEM John A. Hepperlen, East Orange, N. 1., assignor to General Electric Company, a corporation of New York Application March 31, 1930. Serial No. 440,199

6 Claims. (Cl. 164-49 My invention relates to control systems for apparatus employing a web, such as printing presses and the like, and has for its object a simple, reliable and inexpensive system for carrying out certain control operations in dependence upon a function of the web, such as a break or interruption in the web.

In the operation of modern high speed printing presses it is important that some means be provided for detecting a break in the paper or web, and for immediately stopping the press or severing the web back of the plate or type cylinders, or both, because the broken end of the web tends to wrap around the cylinders, thereby causing delay and in some cases damage to the press,

particularly in springing the cylinder shaft.

It has been proposed in printingpresses to provide a shoe which rides on the web and in: case of a break is dropped and thereby caused to carry out certain control operations. However, this sliding shoe has certain disadvantages. It is necessary to raise the shoe out of the way while the paper is being threaded through the press, also the pressure of the shoe on the paper may cause the ink to smear. Sometimes the shoe has a tendency to bounce on the web which may even result in breaking the web. It is an object of my invention to provide a simple and reliable paper break detector which is free from these disadvantages.

In carrying out my invention in one form. I make use of a light sensitive device which is situated on one side of the web with the source 01' light on the opposite side so that upon break-- ing of the web, the light sensitive device is actuated whereby certain desired control operations are carried out. A

For a more complete understanding of my invention reference should be had to the accompanying drawing in which Fig. 1 is a diagrammatic representation of a simplified printing press control system embodying my invention while Fig. 2 is a fragmentary view showing details of construction.

Referring to the drawing, I have shown the invention in one form in connection with an electric motor driven printing press comprising a plurality of press cylinders 10, shown as two couples constituting a typical printing press unit, each couple comprising a type cylinder and an impression cylinder. These cylinders are driven by suitable driving means comprising a start and inching motor 11 and main high speed driving motor 12. The paper or web 13 is fed to the cylinders from a roll 14 over guide rollers 15.

- arm 30 which is driven by a pilot motor 31.

After passing through the two couples of the press, the web passes over a guide roller 16 and thence to a folder (not shown). A paper break detector means is located between the cylinders 10 and the guide roller 16 since it will be observed 50 that a break at this point would result in the end of the paper being wound up on the nearest cylinder as the press continues to rotate whereas, obviously, if a break in the web should occur before it reaches the cylinders, this difilculty r. would not arise.

This paper break detector means comprises a suitable light sensitive device such as a selenium cell or preferably a photoelectric cell which is secured in an opaque or metallic casing 1'7 mounted on a cross bar 18 attached to the press. The photoelectric cell is mounted closely adjacent to the web although far enough away to be out of touch with the web in case the web sags. On the side of the casing 17 adjacent-to the web an 5 orifice or opening 19 is provided to receive light, in case of breakage of the web, from a source of light 20 shown as an incandescent lamp mounted on the opposite side or the web. This light, upon breakage of the web, illuminates the photoelectric cell and thereby controls an electric discharge device 21-which in turn efiects the opening of the driving motor circuit to stop the press and also the operation of a paper severing device 22'to sever the web between the roll 14 and the press. 'As shown the severing device 22 consists of a knife or bar, which is moved into engagement with the web upon the energization of operating coil 23.

It will be understood that any suitable control means for the driving motors 11 and 12 may be provided. The control means disclosed with which the paper break detector control mechanism is associated will now be described in detail.

The two motors 11 and 12 are energized from asuitable direct current source of supply, the connections for the start and inch motor 11 being controlled by means of the contactor switch 26 operated by a coil 27 while the circuit for the main motor 12 is opened and closed by a contactor switch 28 operated by a coil 29. These two switches are further controlled by a switch This switch arm further controls the amount of resistance 32 in the circuit with the armature of the motor 12 and also the amount of resistance 33 in circuit with the field winding 34 of this motor whereby thespeed of the main motor may be varied. The main motor is also provided with a series field winding 35 while the start and inching motor 11 is provided with a series field 36 and shunt ileld winding 37. Furthermore, the control of the motors is effected by means of an "inching" push button 38, a fast" push button 39 and a "slow" push button 40. A stop push button 41 is also provided.

In the operation of the system when the inching button 38 is pressed the circuit is closed from the supply main 24 through the conductor 42, the push button, a contact bar 43, carried on the arm but insulated therefrom, to a conducting segment 44, and thence through a conductor 45 and coil 27 to the supply main 25. This closes the switch 26 whereby the inching motor is started and continues to run as long as the button 38 is held depressed. When it is desired to start the press for a run, the fast button 39 is pressed whereupon a control circuit is closed from the main, 24 through conductor 42, the button, conductor 46, limit switch 47 which is closed, the operating coil 46 of a switch 49 in the circuit of the pilot motor 31 and thence through conductor 50 to the supply main 25. This starts the motor 31, its circuit leading from the main 24 through conductor 51, the motor armature, its series ileld '52, the switch 49, and conductor 50 to the main 25. The motor 31 then operates through its worm gearing connection to turn the arm 30 in a counter-clockwise direction.

At the same time the fast button closes a circuit through the conducting bar 56, secured to the arm 30 but insulated therefrom, to a conductor 57 and through an operating coil 58 and the conductor 50 to the main 25. This coil 58 closes the switches 69 and and opens a switch 61, the switch 59 closing a circuit in parallel to the fast button which may now be released. This circuit leads from the conductor 42 through the stop switch 41, conductor 62, switch 63, which is normally closed, and switch 59 to the conductor 57. The closing of the switch 60 closes a circuit from the supply main 24, as just traced, through the conductor 64, the contact bar 43, the segment 44 and conductor 45 for the operating coil 27 whereby the motor 11- is started to initiate the operation of the press at low speed. At this time the opening of the normally closed switch 61 has no eii'ect on the control.

At the beginning of the movement of the arm 30 by the motor 31, the limit switch 65 is released and closes in accordance with its bias although this does not have any immediate effect upon the control. This slow speed operation 01 the press is continued until the arm 30 has been turned in a counter-clockwise direction to such a position that the contact bar 43 engages with the conducting segment 66 whereupon a control circuit is established from the segment 67 through the contact bar 43 to the segment 66 and thence through the conductor 68 and the operating coil 29 to the main supply main 25 whereby the switch 28 is closed to start the main motor 12. This circuit for the main motor may be traced from the conductor 51 through the contact arm 30 to the conducting segment 69, resistance 32, the segment 70, the armature of the motor, conductor 71 and switch 28 to the supply main 25. A branch circuit leads from the arm 30 through the conducting segment 72, the shunt field winding 34 and conductor 73 to the supply main 25.

The main motor is thus operated at low speed with the entire amount of resistance 32 in its armature circuit and with its shunt field winding fully energized. Immediately after the energize,-

tion of the main motor, the contact bar 43 moves oil the end of the segment 44 whereby the coil 27 is deenergized and the circuit of the starting motor 11 opened.

Upon continued movement of the arm 30 by the pilot motor 31, the resistance 32 is gradually cut out and the field resistance is gradually cut in whereby the main motor is accelerated to full speed, whereupon the contact arm engages the limit switch 4'7 and opens it to deenergize the pilot motor 31.

With the main motor operating at full speed, when it is desired to slow down the press, the slow button 40 is pressed thereby closing a control circuit through the conductor 42, the push button, conductor 75, limit switch 65, conductor 76, operating coil 77 for switch 78 and conductor 50 to the supply main 25, whereby the switch 78 is closed and the pilot motor 31 is started for the opposite direction of rotation, that is, to move the arm 30 in a clockwise direction. For this direction of rotation, it will be observed that the series field winding 79 of the pilot motor is energized. The slow button 40 must be held depressed to continue the operation of the pilot motor 31 and, if it is released, the pilot motor is deenergized and the main driving motor continues to drive the press at a speed corresponding with the position of the arm 30. If the slow button is held pressed long enough, it will be observed that the contact arm 30 will deenergize the main motor and restart the starting motor 11, these control operations being the reverse of those described during the starting of the press.

If at any time it is desired to stop the press, the button 41 is depressed whereby the circuit previously traced for the operating coil 29 or the operating coil 27, as the case may be, is opened, and also the circuit for the operating coil 58 whereupon the switches 26, 28, 59 and 60 drop open, while at the same time the switch 61 is closed. The switch 61 closes a circuit for the coil 77 of switch 78 whereby the pilot motor 31 is started in a direction to return the arm 30 to the starting position shown in the drawing. This circuit leads from the supply main 24 through the conductor 61, switch 61, conductor 61", conductor 75, limit switch 65, which is in the closed position, conductor '76, coil 77 and conductor 50 to the supply main 25. The pilot motor is finally stopped by the opening of the limit switch 65 by the arm 30.

The connections between the driving motor and the web break detector control means operated by the photoelectric cell will now be described. In order that this control means may effect the stopping of the motor, a circuit is provided from the conductor 62 through the operating coil 80 of the switch 63, conductor 81, the normally open relay switch 82, and relay switch 83, actuated by switch 28 so as to be closed when switch 28 is closed, to the supply main 25. Thus when the switch 28 is closed, whereby the press is driven at high speed by the main motor and the relay switch 83 is thereby closed, the closing of the relay switch 82 energizes coil 80 thereby opening the switch 63 to deenergize the main motor, the switch 63, as previously observed, being in series with the stop button 41. The closing of this relay switch 82 is effected by an operating coil 84 in the output of the circuit of the electric discharge device 21. A second relay switch 85 is also closed at the same time by the coil 84 whereby a circuit is closed from the conductor 71 through the conductor 86, relay switch 85, operating coil 23 for the paper severing device, and conductor 87 to the opposite side of the main motor armature. By thus connecting the coil 23 across the terminals of the main motor, it will be observed that the paper severing device is made to operate only when the press is being driven by the main motor, i. e., at high speeds. The severing means is thus responsive to a condition of operation of the motor.

Preferably, the electric discharge device 21 is of -a grid controlled arc rectifier type which is characterized by a large power output controllable by a small amount of grid energy. This device may comprise three electrodes, that is, a plate or anode 87*, a grid 88 and a filament or cathode 89 in a sealed envelope containing a small quantity of an inert gas, such as mercury vapor, whereby the device becomes an arc rectifier, the arc formation between the cathode and anode being controlled by the grid. It will be understood that when the grid is sufilciently positive with respect to the anode, the arc will start but when the grid is more negative than a certain critical voltage value, the arc is prevented from starting by the grid. The output circuit of the discharge device 21 may be traced from the negative supply main 24, conductor 42, switch 41, conductor 62 to the cathode, thence through the discharge device to the plate, conductor 90 and the coil 84 to the positive supply main 25. The grid 88 is connected through a resistor 91 to the conductor 62, leading to the negative supph! main 24, whereby the grid is normally maintained sum ciently negative with respect to the anode to prevent starting of the arc. As shown, the photoelectric cell has its terminals connected by conductors 92 and 93 to the grid and cathode of the discharge device, the cathode of the photoelectric .cell preferably being connected to the grid. Ad-

justable resistances 94 and 95 are connected in the heating circuit for the cathode 89, which circuit leads from the conductor 62 through the resistor 94, the cathode, the resistance 95, conductor 96, conductor 86 and switch 28 to'the supply main-25.

In the operation of the system, the photoelectric cell is normally shielded from the source of light by the web so that its resistance is very high and consequently the grid of the discharge device is sufficiently negative to prevent the formation of an arc. However, when the paper breaks, the photoelectric cell is illuminated from the light source 20. whereupon the resistance or the photoelectric cell is very greatly decreased and the grid voltage of the discharge device 21 thereby made much more positive with respect to the anode voltage. In other words, the grid will be connected at that time through the conductor 92, photoelectric cell, conductor 93,v a portion of resistance 95 and conductor 96 to the positive supply main 25. The are then starts in the discharge device whereby the ccil 84 is energized to close the relay switches 82 and 85 and hence stop the press and sever the web. It will be observed that the opening of the switch 28 to stop the motor also interrupts the connection of the heating circuit of the cathode 89 with the supply main 25, although the cathode remains energized from the motor voltage for an appreciable length of time, thus holding the web severing device 22 in the severing position for a desired interval.

When the motor comes to rest, however, the

'lli

In Fig. 2 I have shown means for mountin the photoelectric cell so as to provide for diflerent widths of web. As indicated for full width the web is four pages wide, pages being indicated by the squares 100. At times, however, the web will only be a fraction of its full width and consequently to .provide for the positioning of the photoelectric cell always at a point opposite the web, it may be moved on its supporting bar 18 to such position. Preferably, however, a plurality of lights 20 are used, so arranged that some one will be in the proper position. As shown four lights are provided, these lights being placed respectively opposite the pages 0! the press and the photoelectric cell being adjustable to a desired selected position opposite some one of them.

It will be understood that when a plurality of press units are being operated in parallel, each with its own photoelectric cell web break detector and severing device and each having relay switches 82 and 85, the relay switches 82 of the units will be connected in parallel with each other so that the closure of any one due to the breaking of the web in the particular unit will shut down the press.

While I have shown a particular embodiment of my invention, it will be understood, 0! course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent 0! the United States is:

1. The combination with a printing press, or no the like, of a driving motor therefor, web severing means and means responsive to the energizetion of said motor for operating said ,web severing means.

2. The combination with a printing press, or us operating means across terminals of said motor.

3. The combination with a printing press, or the like, or a motor for driving said press, web severing means, and means jointly responsive to the continuity of the web and the energization of said motor for controlling said severing means.

4. The combination with a printing press, or the like, of low and high speed driving motors for said press, web severing means, and means joint-1y responsive to the continuity of the web and the energization of said high speed motor for operating said severing means.

5. The combination with a printing press, or the like, of a driving motor for said press, web severing means and means responsive to the continuity of the web for connecting said severing means across a predetermined portion or the circuit of said motor.

, 6. The combination with a printing press, or the like, of a driving motor therefor, a switch for said motor, an electric discharge device provided with a cathode circuit for controlling said switch, means responsive to the continuity of the web for operating said discharge device, a source of electrical supply for said motor and connections between the cathode circuit of said discharge device and said source including said switch.

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