US2080575A

US2080575A - Photoelectric register control

Info

Publication number: US2080575A
Application number: US736143A
Authority: US
Inventors: William R Perry
Original assignee: Reeves Pulley Co
Current assignee: Reeves Pulley Co
Priority date: 1934-07-20
Filing date: 1934-07-20
Publication date: 1937-05-18
Anticipated expiration: 1954-05-18

Description

FIPszlz xR 2,080,575 y May 18 1937. w. R. PERRY 2,080,575

raoomcrmnsors'rnn conrRoL Filed July 2o, 1954 2 sheets-sheet 1 May 18, 1937. w. R. PERRY PHOTOELECTRIC REGISTER CONTROL Filed July 20, 1934 2 Sheets-Sheet 2 E11 I 33" NN NRJ IHIHI 1 l x l l 1 mm. Sw wf @R m l e m. vmmw. A* H @n L. Q RN @nl @l v RNI/ NNI Nw Patented May 18, 1937 UNITED STATES PATENT OFFICE Reeves Pulley Company,

lumbus, Ind., a

corporation of Indiana Application July 20, 1934, Serial No. '136,143

13Cla1ms.

In some instances it is necessary or desirableto feed a continuous strip or web of material in such a manner as to permit accurate periodic l treatment thereof rather than to feed cut sheets to a treating mechanism because it is more economical to prepare and supply the material pretreated in some manner, as by printing, in a continuous web upon a roll rather than as cut sheets. For instance, the present trend in packaging articles is Vto supply the wrapping material from a continuous web having recurring designs or indicia thereon and to cut the web of material into predetermined lengths in accordance with 20 the design previously placed upon the web and just prior to packaging or wrapping. 'I'his manner of handling the wrapping material however requires accurate registration of the web with respect to the knife and to the design on the web, because oi stretch and shrinkage in the web and of possible irregularities or inaccuracies in the printing of the web. The maintenance of proper registration is increasingly more important and the problems involved are increased because when 30 the material is handled as a web, the'cutting knife is not driven from the same source that feeds the web when it is being printed, but from a separate drive and accordingly any errors arising from differences in speeds .of movement of 3,-, the paper and/or knife are cumulative.

Many attempts have been made to control the registration of a web of material, including photoelectric controls, so that the web may be cut into predetermined lengths or otherwise treated in 40 accordance with previously impressed designs.

Such attempts, so far as I am aware, have involved complicated and costly mechanisms and have been unsatisfactory because of inherent deciencies in their operation and response par- 45 ticularly as to speed of operation, non-uniformity,

and inaccuracy.

It is the purpose of this invention, therefore, to provide an improved photoelectric register control which overcomes the heretofore mentioned deficiencies, particularly as to cost of manufacture, installation and maintenance, and speed of operation.

Other objects of my invention and their resultant advantages will be apparent from the CTI (Cl. 27h-2.6)

following description given in connection with drawings, in which Figure 1 is a schematic representation of one emobdiment of my invention;

Fig. 2 is a similar schematic view in slightly modiiied form of my invention; and

Fig. 3 is an electrical diagram of a modified application of my invention.

Having particular reference to Fig. 1, I have illustrated a system which is controlled by means of a photoelectric cell controlling an amplifier circuit employing ionic tubes and which system involves very little mechanical means thereby reducing the cost of manufacture and substantially eliminating any time lag in operation. To insure uniformity of operation and elimination of any hunting effects, I have found it desirable to introduce a continuing error in the rate of movement of the web relatively to the treating mechanism and to compensate for this error by a periodic displacement of the web of material as occasion demands, rather than vary the rate of movement of the web or treating devices, which 'is productive of hunting or continuous alternate over-corrections.

As illustrated in Fig. 1, the web of transparent material l having recurring spaced opaque indicia 2 adjacent one edge is fed from a roll 3 by feed rolls l, one at least of which is positively driven from the main or primary shaft 6 of a Reeves variable drive 1 driven from a constant speed motor 8. The rolls 4 feed the web to the treating devices, in the present instance a knife 9, carried by the upper of a pair of rolls Il. The

knife rolls are driven from one shaft I2 of a diilerential mechanism I3, the housing of which is driven by a belt Il passing over a' pulley i6 on a shaft i1 which is connected to or is an extension of the variably driven or secondary shaft I8 of the Reeves variable drive. Accordingly, the knife is driven from the same motor 8 which drives the feed rolls and at a predetermined rate which may be varied by adjustment of the Reeves variable drive in the well known manner to suit the circumstances. The rate of drive of the knife is preferably adjusted so that it normally operates a little faster, i. e.. the web is fed a little slower, than would be necessary to cut the web into the required lengths as indicated by marks 2.

As previously stated, a relative displacement .of the web to the cutting knife is made by periodic displacement of the relative positions of the web and the knife rather than by periodic variation in the speed of movement. This correction is controlled by a photoeiectric cell and associated circuits. Furthermore the electrical circuits are not made to perform their work such as displacing the web or varying the rate of movement. but are employed only as a trigger or tripping means to permita correction to be made by some other means.

Accordingly, a photoeiectric cell or tube I9 is disposed beneath the web of material and is so shielded that it receives illumination only from a lamp 2| disposed above the web of material. Because in the illustrated form of this invention the web is transparent and the indicia are opaque the source of light 2| is cut off from the photo-tube when the indicia appear between the photo-tube and light. The varying conductivity of the photo-tube, dependent upon the position of indicia 2, is used to control thevow of current through an amplier comprising two dissimilar ionic or gaseous conduction discharge tubes which control Aanother source of electrical energy for operating electrical devices which in turn control the actuation of the knife rolls as follows:

'Ihe amplier current controlled by the phototube is derived from a transformer 22, the primary 23 of which is connected to: any suitable source such as a 110 volt A. C. source. I'he secondary winding 24 is connected to the plates of full wave rectifier tube 25, the filament of which is heated from another secondary winding 26. A third 'secondary winding 21 is used to supply current to the lamp 2|. The rectified current delivered from the rectier 25 is conducted by one lead 28 taken from the center of the secondary winding 26 and a second lead 29 taken from the center of the secondary winding 24 through a lter 30 across a pair of resistances 3| and 32, connected in series.

A lead 33 from the outer end of a 'resister 3| is connected to one side of a gaseous discharge device comprising a pair of

ionic discharge tubes

34 and 36 such as a "Raytheon B. R." tube and a "Gen. Elect. neon glow G10" tube, respectively, connected-in series. Any other tubes having the desired dissimilar characteristics may be employed. It is only necessary that tube 34 require a relatively high voltage such as 200 volts to cause it to trip or ignite and that it continue to glow at a relatively low voltage such as 50 volts, that it have a relatively high voltage drop ordifferential and that tube 36 require a relatively low voltage such as 60 to cause it to ignite and that it continue to glow at a voltage of approximately 55 volts, that it have a relatively low voltage drop.

A leak resistance 31 is connected across the two tubes and a stabilizing resistance 38 is connected across the neon tube. A variable balancing condenser 39 is connected across tube 36 to balance the capacity of the grounded shield 40 surrounding the photo-tube lead. The condenser can be varied to balance any reasonable length of shield. From the two

tubes

34 and 36 the circuit continues through conductor 4| to a timing device 42 comprising apair of contacts 43 and then through conductor 44 to relay 46 controlling a pair of contacts 41 and to the opposite side of the resistances 3| and 32, i. e., the outer end of resistance 32 to which it may be Ivariably connected. 'Iiming device 42 is driven from shaft |2 through sprockets 43 and chain 49 in synchronism with the cutter, and is so timed that contacts 43 are closed when the knife 9 is in a definite position in its rotation.

Contacts 41 of the relay in the amplifier circuit control a solenoid 6|, being connected thereto by conductors 62 also connected to the 110 volt A. C. source of supply. Solenoid 5| controls an escapement mechanism or actuator 53 connected to the other shaft 54 of the differential l3. The escapement mechanism is so arranged that upon energization of ,the solenoid 5| shaft 54 is released, to rotate one tooth of the escapement mechanism 53 at each complete cycle of operation of the solenoid. Rotation of shaft 54 in the same direction as shaft |2 of the differential mechanism retards rotation of shaft l2 lwhich drives the knife roll and consequently ment between the web and the knife except momentarily after which the rate of movement is the same as before.

It will be understood that because the diierential housing is driven from shaft |1 yand a load is placed upon shaft i2 by the knife roll, shaft 54 of the differential will tend to rotate in the same direction as shaft I2, but is retained thereagainst by the escapement mechanism.

It will be seen from the foregoing that the web of material is fed at a constant rate of speed as is the knife, and that the difference in movement of the paper and knife may be adjusted by varying the Reeves variable drive. Preferably, the drive is so adjusted that the web is fed slightly slowe1 than is necessary to cause cutting of the web in desired lengths and periodic corrections are made to compensate for the continuing error. Consequently, whenever the web gets out of registration sufllciently that a mark 2 intercepts the beam of light from lamp 2| to the photoeiectric cell I9 when the contacts 43 are closed, lack of illumination of the photoeiectric cell will cause it to be relatively non-conductive and the conductive shunt around the tube 34 provided by the photo-tube when it is illuminated, is interrupted. This raises the potential across tube 34 to a point where itignites and in turn impresses a greater potential across tube 36 which will in turn ignite, causing a current ow through both

tubes

34 and 36 and relay 46, closing contacts 41. This energizes solenoid 5| which actuates the escapement mechanism 53. Actuation of escapement mechanism 53 permits limited rotation of shaft 54 which is normally urged counterclockwise by the means previously described and therefore tends to, or is capable of changing the position of the web by momentarily retarding rotation of shaft |2 and delaying operation of knife 9. The escapement movements are repeated if necessary until the web has reached the desired position relatively to the knife. After the necessary correction normal operation is resumed until it is again necessary to correct for the continuing error.

Although the light from lamp 2| is cut off from the photo-tube every time a mark 2 passes between the tube and light, it is inoperative to cause operation of the escapement mechanism except when timer contacts are closed because at all other times the circuit is broken because oontacts 43 are open. Since the web is fed slightly mavalspeed of rotation of the knife roll relatively to the feed roll by adjusting the Reeves variable drive in the usual manner.

It has been assumed that the web of material is transparent and that the indicia thereon are opaque. If it is -desired to reverse this condition and control registration of a web of opaque material by transparent indicia it is only necessary to reverse the positions of the two

tubes

34 and 36 as shown schematically in Fig. 3. 'I'his is possible because ignition of tube 36 does not cause a sufnclent voltage drop to ignite tube 34, but ignition of tube 34 does create a sufiicient voltage drop to trip or ignite tube 36.,

Accordingly, if an aperture or transparent spot permits suillcient illumination of the photo-tube when contacts I3 are closed, the resistance of tube I9 drops and a greater potential is applied to the tube 34, causing it to glow and in turn trip tube 36 completing the circuit through the relay 46. When the photo-tube is dark the resistance thereof is substantially equal to or greater than that of resistance 36 and the voltage is so divided that tube 34 does not trip although tube 36 may be ignited. The foregoing is one advantage of having the two tubes 3l and 36 of dissimilar characteristics. A further advantage is that overillumination, if such should occur, in the circuit shown in Fig. 1. would place a higher voltage across tube 36 but would not trip tube 3l because tube 36, as heretofore stated, does not have a great voltage differential. Under-'illumination does, however, trip tube 34, and because of its relatively large voltage differential, causes tripping or ignition of tube 36 and operation of the circuit of Fig. 1.

In Fig. 2 there is shown a modification of my invention which is similar to the form illustrated in Fig. 1, in most respects including the elements used, but differs from the Fig. l form in that movement of the feed rolls rather than movement of the knife is momentarily increased to cause relative displacement of the web. For this reason the knife carrying roll Il is driven from the main shaft 6 of the "Reeves variable drive", and the feed rolls l are driven from shaft i2 of the differential i3, the housing of which is 'driven from the secondary shaft I6 of the Reeves Varlable drive. 'I'he other shaft 64 of the differential mechanism to which is attached the escapement mechanism is constantLv urged in the reverse direction by a slipping drive belt 60 passing'over a pulley 6i on shaft 64 and a pulley 621 secured to shaft I6. When shaft 5I is held against rotation by the actuator 63 belt 60 slips, but when the actuator mechanism is operated, belt 60 drives shaft 6l through a limited arc clockwise against the counterclockwise movement of shaft I2 and thereby momentarily increases the speed of rotation of shaft l2 and movement of feed rolls 4. In all other respects the form of invention illustrated-in Fig. 2 is similar to that illustrated in Fig. 1 and the various elements are given the same reference characters although their positions are graphically changed.

From the foregoing description it will be apparent that the web of material may be uniformly Y -and continuously kept in register relative to the release certain elements to permit operation thereof and because variation in movement of any massive parts having appreciable moment of inertia is eliminated. The electrical equipment necessary and its cost is reduced to a minimum and the circuits involved are stable and capable of immediate and repeated operation in response to the position and movement of exceedingly small indicia resulting in registration control that offers substantially no limitations to the speed of operation of the feeding and treating mechanisms.

It will be apparent to those skilled in the art that minor changes may be made in the details on said `web and means comprising a gaseous-- discharge tube, an electro-responsive device and timing switch contacts connected in series and operatively connecting said photoelectric cell and said escapement mechanism whereby the latter is controlled by said photoelectric cell.

2. In an apparatus for maintaining registration of a web having recurrent indicia thereon relatively to a web treating device, means for driving said treating device, means for feeding said web, including a differential mechanism having one shaft thereof connected to said web feeding means, an escapement mechanism for controlling rotation of the other shaft of said differential mechanism, a photoelectric cell, a source of light for said cell interrupted by the recurring indicia on said web, and means comprising a gaseous discharge tube, an electro-responsive device and timing switch contacts connected in series and operatively connecting said photoelectric cell and said escapement mechanism whereby the latter is controlled by said photoelectric cell.

3. In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for continuously moving said web and said treating device relatively to each other at .speeds other than that necessary to maintain registration of said web at predetermined intervals, a gaseous discharge device, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected to said dis-A charge device for controlling the latter, an electro-responsive device connected to said discharge device, means controlled by said electro-responsive device for relatively varying the position of said web relatively to said treating device in response to variations in the conductivity of said discharge device under the control of said light sensitive device to tend to bring said treating device and web into registration at predetermined intervals. and means including a timing switch connected in series with said gaseous discharge device and driven in synchronism with said treat-'- ing device and arranged to prevent operation of said advancing means when said web is in registration at predetermined intervals.

@minimali 4. In an apparatus for maintaining registration of a web having recin'rent indicia thereon at predetermined intervals relatively to a web treating device, means for continuously moving said web and said treating device relatively to each other at speeds other than that necessary to maintain registration of said web at predetermined intervals, a gaseous discharge device, a source oi' direct current therefor, a light' sensitive device positioned to respond to the recurrent indicia on said web and connected to said discharge device for controlling the latter, an electro-responsive device connected to said discharge device, a rotary escapement mechanism controlled by said electro-responsive device for relatively advancing the position of said web relatively to said treating device in response to variations in the conductivity of said discharge device under the control of said iight sensitive device to tend to bring said treating device and web into registration at predetermined intervals, and means including a timing switch connected in series with said tube and driven in synchronism with said treating device and arranged to prevent operation of said escapement mechanism when said web is in registration at predetermined intervals.

5. In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on the web, a gaseous discharge device, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected in the anode circuit of said discharge device for controlling the latter, an electro-responsive device connected to said discharge device, means controlled by said electro-.responsive device for advancing the position of said web relatively to said treating device in response to variations in the conductivity of said discharge device under the control of said light sensitive device to cause said treating device and web to operate in a predetermined relationship, and means including a timing switch connected in series with said discharge device and having one contact connected to the anode thereof, said switch being driven in synchronism with said treating device and arranged to prevent operation of said advancing means ,when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

6.l In an apparatus for maintaining registration of,a web having recurrent indicia thereon at predetermined intervals relatively to aweb treating device, means for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on'the web. a gaseous discharge device, a source of direct'current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected in the anode circuit of said discharge device for controlling the latter, an electro-responsive device connected to said discharge device, means controlled by said electro-responsive device for advancing the position of said web relatively to said treating device in response to variations in the conductivity of said discharge device under the control oi said light sensitive device to cause said treating device and `web to operate ina predetermined relationship, and means including a timing switch driven in synchronism with said treating device and connected in series with said electro-responsive device and arranged to prevent operation of said advancing means when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

7. In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on the web, a rotary escapement mechanism for varying the relative speeds of said web and treating device. a gaseous discharge device, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected to the anode of said discharge device for controlling the latter, an electro-responsive device for controlling said escapement mechanism connected to said discharge device, in response to variations in the conductivity of said discharge device under the control of said light sensitive device to cause said treating device and web to operate in a'predetermined relationship, and means including a timing switch in sexies with said electro-responsive device and driven in synchronism with said treating device and arranged to prevent operation of said escapement mechanism when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

8. .In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on the web, a gaseous discharge device, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicla on said web and connected to said discharge device for controlling the latter, an electro-responsive device connected to said discharge tube, a rotary escapement mechanism controlled by said electro-responsive device for advancing the position of said web relatively to said treatingdevl'ce in response to variations in the conductivity of said discharge device under the control of said light sensitive device to cause said treating device and web to operate in a predetermined relationship, and means including a timing switch connected in series with said electro-responsive device and driven in synchronism with said treating device and arranged to prevent operation of said escapement mechanism when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

9. In an apparatus for-maintaining registra` tion of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, vmeans for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at'predetermined recurrent points on the web, a gaseous discharge device, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected to said discharge device for controlling the 1atter,an

electro-responsive device connected to the anode of said discharge device, in series with said source of .direct current, means controlled by said electro-responsive device for advancing the position of said web relatively to said treating device in response to variations in the conductivity of said discharge device under Vthe control oi said light sensitive device to cause said treating device and web to operate in a predetermined relationship, and means including a timing switch driven in synchronism with said treating device and connected in series with said yelectro-responsive device and source of direct current to the anode of said discharge device and arranged to prevent operation of said advancing means when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

10. In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on the web, a pair of gaseous discharge tubes connected in series with each other, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected to said discharge tubes for controlling the lattter, an electro-responsive device connected to said discharge tubes, means controlled by said electro-responsive device for advancing the position of said web relatively to said treating device in response to the conductivity of said discharge tubes under the control of said light sensitive device to cause said treating device and web to operate in a predetermined relationship, and means including a timing switch connected in series with said tubes and driven in synchronism with said treating device and arranged to prevent operation of said advancing means when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

11. In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for feeding said web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on the web, a pair of gaseous discharge tubes connected in series with each other, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected in shunt to one of said discharge tubes for controlling the latter, an electro-responsive device connected to said discharge tubes, means controlled by said electro-responsive device for advancing the position of said web relatively to said treating device in response to the conductivity. of said discharge tubes under the control of said light sensitive device to cause said treating device and web to operate in a predetermined relationship, and means including a timing switch connected in series with said tubes and driven in synchronism with said treating device and arranged to prevent operation oi said advancing means when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

12. In an apparatus for maintaining registration of a web having recurrent indicia thereon at predetermined intervals relatively to a web treating device, means for feedingisaid web, means for operating said treating device at a relatively greater speed than necessary to cause said treating device to operate at predetermined recurrent points on the web, a pair of gaseous discharge tubes of dissimilar characteristics connected in series with each other, a source of direct current therefor, a light sensitive device positioned to respond to the recurrent indicia on said web and connected in shunt to one of said discharge tubes for controlling the latter, an electro-responsive device connected to said discharge tubes, means controlled by said electro-responsive device for advancing the position of said web relatively to said treating device in response to the conductivity of said discharge tubes under the control of said light sensitive device to cause said treating device and web to operate in a predetermined relationship, and means including a timing switch connected in series with said tubes and driven in synchronism with said treating device and arranged to prevent operation of said advancing means when the treating device is in advance of the desired position relatively to the position of said indicia on said web.

13. In an apparatus for maintaining registration of a web having recurrent indicia thereon relatively to a web treating device, means for feeding said web, means for driving` said treating device, a differential mechanism having one shaft thereof connected to one oi said means, an escapement mechanism for controlling rotation of the other shaft of said differential mechanism, a photoelectric cell, a source of light for said cell interrupted by the recurring indicia on said web and means comprising a gaseous'discharge tube, an electro-responsive device and timing switch contacts connected in series and'operatively connecting said photoelectric cell and said escapement mechanism whereby the latter is controlled by said photoelectric cell.

W'IILIAM R. PERRY.