US3850123A

US3850123A - Can registration and position system

Info

Publication number: US3850123A
Application number: US00390242A
Authority: US
Inventors: R Mazur; J Larocca; J Mcgrail
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1973-08-21
Filing date: 1973-08-21
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26
Also published as: CA996234A; GB1482118A

Abstract

The main turret of a can deforming machine carries a number of work stations. Each station includes a platen for rotating a can; a drive motor for rotating the platen; a tachometer for providing a negative feedback signal; an encoder for generating a large number of pulses per revolution of the platen; and a scanner which distinguishes between light and dark background on the can so as to detect the presence and absence of a circumferentially extending registration marking on the can. The drive motor is energized by a feedback servo amplifier. A common control system selects a station in turn and includes a timer which establishes a control time in which the can is accelerated to a standard rotational speed and within which time the registration mark is first to be verified and then to disappear from the view of the scanner. A counter counts pulses from the encoder while the presence of the registration mark persists and is reset when the counter reaches a predetermined verifying count. The counter commences counting again when the end of the mark is reached and this count is compared to a preset count which may be different for each station. The comparison output is used to decrease the positive input of the servo amplifier to zero when the counter reaches the preset count, thereby to stop the can at a selected position at its station which is determined by the preset count.

Description

United States Patent [191 LaRocca et al.

[ Nov. 26, 1974 CAN REGISTRATION AND POSITION SYSTEM [75] Inventors: James J. LaRocca, LaGrange; John G. McGrail, River Forest; Richard A. Mazur, Downers Grove, all of I11.

[73] Assignee: Continental Can Company, Inc.,

New York, NY.

[22] Filed: Aug. 21, 1973 [21] Appl. No.: 390,242

[52] US. Cl. 113/113 C, 113/115 [51] Int. Cl B21d 43/14 [58] Field of Search 113/115,113 C, 114 C, 113/1 R; 72/9, 37, 1

[56] References Cited UNITED STATES PATENTS 2,877,729 3/1959 Peterson, Jr. 113/115v 3,604,380 9/1971 Schmeltzer 113/113 C 3,618,550 11/1971 Mojden et al 113/113 C Primary Examiner-Richard J. l-lerbst Attorney, Agent, or FirmDiller, Brown, Ramik & Wight [57] ABSTRACT The main turret of a can deforming machine carries a number of work stations. Each station includes a platen for rotating a can; a drive motor for rotating the platen; a tachometer for providing a negative feedback signal; an encoder for generating a large number of pulses per revolution of the platen; and a scanner which distinguishes between light and dark background on the can so as to detect the presence and absence of a circumferentially extending registration marking on the can. The drive motor is energized by a feedback servo amplifier. A common control system selects a station in turn and includes a timer which establishes a control time in which the can is accelerated to a standard rotational speed and within which time the registration mark is first to be verified and then to disappear from the view of the scanner. A counter counts pulses from the encoder while the presence of the registration mark persists and is reset when the counter reaches a predetermined verifying count. The counter commences counting again when the end of the mark is reached and this count is compared to a preset count which may be different for each station. The comparison output is used to decrease the positive input of the servo amplifier to zero when the counter reaches the preset count, thereby to stop the can at a selected position at its station which is determined by the preset count.

11 Claims, 4 Drawing Figures L 68 52 consmnr SPEED w women PRESET couur 53 Q6 1 snuace YPICAL MAQHINE era. 1 50 J 54 14 M 2 8 Ai r 16 2 k g,g as

D L T I 4 /A COMPARATOR l 1 l i mmen' lNHiBlT l Egan 36 l I an CDUNTER s eese'r 48 I8 I I6 I an 1 A '16 L MARK PM VERlFY \Z 26 I 64 X 77. Z

rwlcniuncumasmnon 46 ews 1- 1E: '28 I i r can QFJECT l e, I 44 at I I 361 i {42 g I I 33' EATING- 3% 5 SYSTEM TMER {FE T IS e 32 30' a l l CAN REGISTRATION AND POSITION SYSTEM CROSS REFERENCE TO RELATED APPLICATIONS This application relates to a machine of the type described in copending application Ser. No. 221,587, filed .Ian. 28, 1972, now US. Pat. No. 3,807,209 granted Apr. 30, 1974, and illustrates details of the control circuitry for such a machine, now US. Pat. No. 3,807,209.

BACKGROUND OF THE INVENTION Cans or other tubular bodies may be required to be deformed, as by embossing or the like, in registration with printed matter which appears on the surface of the body. The body may be enclosed within a mold and internal pressure utilized to effect the deformation such as embossing and in order to achieve a reasonable rate of production, a number of such molding stations may be provided on the main turret of a machine. At each station, the can or tubular body must bepositioned at a precise angular disposition in order that the printed matter on the body may be in exact registry with the mold assembly and each such position may be unique or peculiar to each station.

BRIEF SUMMARY OF THE INVENTION It is of principal concern in connection with the pres ent invention to provide, in a machine of the type described above, means whereby precise registration of each body is effected at each of the stations. For this purpose, each station is provided with a scanning means which detects the presence or absence of the registration marking on the body which may be a circumferentially extending line or mark specifically provided for this purpose or it may be constituted by the printed material itself but, in any event, the output of the scanning means is utilized in conjunction with the output of pulse generating means which produces a large number of pulses per revolution of the body. The combination of the pulses and scanning output is utilized first to verify that the orientation means seen" by the scanning means is in fact the correct marking. Timing means initiated at the beginning of a cycle is utilized in conjunction with the output of the scanning means and of the marked verification means alternatively to effect a reject signal in the event that no registration mark is verified during the timing cycle or to produce a signal which is effective to enable the drive input of the associated platen to be reduced to zero after a selected number of pulses have been generated by the pulse generating means subsequent to detection of the end of the registration mark which constitutes the orientation means.

Specifically, the pulse generating means is used to drive a counter andif this counter initially reaches a predetermined count, the orientation means is verified and the counter is reset to zero and commences counting again at the end of the registration mark. The output of the counter at the commencement of counting at the end of the registration mark is utilized to effect the variable or decreasing power output to the drive means for the platen. Specifically, this is accomplished by outputting the counter count to a comparison device which compares the count to a preset stopping point count which may be adjusted or selected individually for each work station of the machine. Initially, the platen is accelerated at the beginning of the cycle to a selected speed and after verification and termination of the registration mark as seen by the scanning means, the drive means for the platen is maintained at the preselected drive speed and subsequently is decreased rapidly to zero by the stopping point number comparison with the counter output. The output of the counter is a multi-bit digital word and the stopping number correspondingly is a multi-bit digital word and the output of the comparator is applied to a digital-to-analog converter which functions as the variable power source to effect final registration of the body.

BRIEF SUMMARY OF THE DRAWINGS FIG. 1 is a block diagram illustrating certain principles of the present invention in conjunction with a multi-station machine;

FIG. 2 is a block diagram illustrating certain principles of the control circuitry;

FIG. 3 is a circuit diagram of an illustrative embodiment of the invention and showing the main logic function of the control means; and

FIG. 4 is a circuit diagram illustrating the means by which the preset stopping point numbers are achieved in the system.

DETAILED DESCRIPTION OF THE INVENTION The aforementioned commonly assigned application Ser. No. 221,587 is incorporated herein by reference thereto and two stations of such machine on the main turret thereof are symbolically illustrated and are indicated respectively by

reference characters

10 and 12 in FIG. 1. As shown, each station includes a low inertia d.c. motor 14 for driving a shaft 16 which rotates a platen 18 on which the tubular body or can 20 is mounted. The shaft also drives a tachometer 22 having a negative feedback output at the conductor 24 to a servoamplifier 26 which has an output at 28 connected to the drive motor 14. Each shaft also drives a pulse generating means 30 which may be in the form of an optically actuated direction sensing encoder capable of producing 2500 pulses per revolution of the shaft 16 and the train of pulses produced by the means 30 appears at the output conductor 32 as shown. It will be appreciated that the servoamplifier 26 preferably is not located at the machine station 10 but that a separate speed servoamplifier is provided for each station in the control circuitry section as indicated generally by the reference character 34.

Each station further includes a fixed scanning means 36 which is positioned to look at the exterior surface of the tubular body or can 20 so as to detect the presence or absence of an orientation means such as the registration mark 38 indicated in FIG. 1. The output of the scanning means 36 is applied over the conductor 40, as shown.

The above reference characters and description are applied with reference to the machine station 12 and it will be understood that further machine stations may be provided as necessary and desired, such as the machine station indicated by the reference character 12 and for which corresponding primed number are utilized in FIG. 1.

The control section 34 includes a gating system 42, a timing means 44, a registration or orientation means verification means 46, a counting means indicated generally by the reference character 48 and drive means for energizing the various motors 14, 14', etc. This drive or power means is effective initially to accelerate each platen rapidly from standstill to a predetermined angular velocity which may be, for example, 1000 RPM. Upon verification of the mark and when the end of the mark is seen by the scanning means a decreasing power output function is initiated ultimately to decrease the power at the conductor 50 to zero upon the attainment of a predetermined or preselected number of pulses from the pulse generating means 30 which have occurred subsequent to termination of the presence of the orientation means 38 as seen by the scanner 36. Thus, the power means may include a constant speed power source 52 and a variable power source 54 which is in the form of a digital-to-analog converter driven from the output of a comparator 56. A preset or stopping point count is applied to the comparator 56 from the preset count means 58 and the comparator also receives the output of the counting means 48, as shown. The mark verification means 46 receive certain of the output bits from the counter means 48 so as to be actuated by these inputs upon the attainment of a predetermined verification count as reached by the counting means 48.

When each station on the main turret reaches a predetermined position, a mechanical switch may be actuated to initiate the cycle of operation for that particular station and such switching means is symbolically illustrated and indicated by the reference character 60 in FIG. 1. The actuation of the switch means 60 initiates the timing cycle and also functions to perform ancillary switching operations as symbolically illustrated by the

switches

62, 64, 66 and 68. The switching function at 62 functions to connect the appropriate scanning means 36, 36, etc. to the gating system 32', the switching means 64 functions to connect the appropriate pulse generating means 30, 30', etc. to the counter means 48; the switching means 66 functions to connect the power output 50 to the

appropriate servoamplifier

26, 26, etc. and the switching means 68 functions to energize the appropriate input line 70 72, etc. to the preset means 58. As will be later described, the preset means 58 is a cross point matrix system in which the selected cross points are connected by diodes to output the requisite digital number on the output lines of the preset means 58, as will appear hereinafter.

In general, the gating system 42 responds to the scanning means to remove a reset signal at 72 to the counter means 48 when the orientation means 38 is seen by,

the scanning means so as to allow the counter means 48 to begin a count from zero and after verification of the mark by reason of continued energization of the scanning means for a predetermined number of counts, the counter means 48 is reset and held reset until the orientation means disappears from the view of the scanning means whereupon the counting means 48 again begins to count from zero whereby to initiate a stopping point portion of the cycle. The end of the mark as seen by the scanning means also generates a signal at 74 to inhibit the constant speed power source 52 and the absence of mark verification will inhibit the variable power source means 54 as indicated by the conductor 76. At the end of the timing cycle, if the mark has not been verified, a reject signal is applied at the conductor 78 and mark verification can occur only during the timing cycle by reason of an interlock signal applied at the conductor 80 as indicated.

In a preferred embodiment of the system, the timing cycle has a duration of 140 milliseconds, each can is accelerated rapidly to rotate at 1000 RPM and each pulse generating means produces 2500 pulses per revolution of the platen and each can is stopped at a point from between 120 to 480 subsequent to the termination of the registration mark as seen by the scanning means.

Reference to FIG. 2 will reveal the functioning of the preferred embodiment in greater detail. As shown, the positive power output to the servoamplifiers is applied at the conductor 86, the input from the input from the appropriate scanning means is applied at the conductor and the cycle starting switch is indicated by the reference character 92. The counter means 48, constant power source means 52, variable power source means 54, comparator means 56 and preset count means 58 have previously been described but in FIG. 2 the control logic is expanded somewhat to describe the operation thereof with greater particularity. As shown, mark verification is effected by means of a gating circuit 94 having one input from the counter as indicated at 96 and the other input at 98 from the scanning means so as to produce at its output 100 a signal under conditions in which the scanning means indicates that the orientation means is still being looked at while the counter means 48 has reached a predetermined count, the time taken for which is indicative that the scanning means is looking at the proper orientation means. The signal at the conductor 100 is applied to a gate 102 and is effective to cause the gate to output a reset signal at the conductor 104 to the counter means 48 and this reset action holds the counter means 48 at zero count until the output state at the conductor 106 of the end of mark gate 108 is changed whereupon the counter 48 -will commence counting againg but this time from the end of the registration mark of orientation means.

The logic for the end of the mark is derived by coincidence of the three inputs to the gate circuit 108 as indicated in FIG. 2, one of them as indicated at 110 being from the timer circuit 112, the second being the change of state of the verification circuit 94 as indicated at 112 and the third at 114 being from the scanning means. Thus, if mark verification has been effected an input is to the line 112 and the timer is still running as indicated by the input at 110 and the input from the scanning ,means at 114 is such as indicates that termination of the orientation means has occurred, the end of the mark gate means 108 will output at 106. In the embodiment shown in FIG. 2, the gate means 102 is an OR gate so that the presence of an input to either of its inputs applies the reset signal at the conductor 104. This also has the effect of resetting the counter to zero and allowing recommencement of a count in the event that a false registration mark is seen by the scanning means. For example, if the scanning means perceives the orientation means or registration mark and such registration mark is false as indicated by the fact that it does not persist long enough for the counter means 48 to achieve the predetermined count which verifies it, disappearance of the registration mark form the view of the scanning means will cause the gate means 108 to output at 106 and to reset the counter and hold it reset at zero until the scanning means sees the next mark whether such next mark be false or not and at which time the counter means will begin to count from zero again. The gating system further includes a reject gate means 116 having one input 118 from the timer means 112 and the other input at 120 from the mark verification circuit 94. The functioning of this reject gate means 116 is such that if the mark verification means 94 has not outputted by the time the timer runs out, a reject signal will appear at the output conductor 78 whereas if the verification means 94 has outputted and the cycle time has run out, an inhibiting signal at the conductor 122 which is normally applied to disabled variable power source means 54 will be removed to allow the variable power source means 54 to take over the drive control to the appropriate servoamplifier. Prior to this time, when the circuit 108 has outputted, the output signal thereof is effective to produce an inhibit signal at the conductor 124 controlling the constant power source means 52.

FIG. 3 illustrates a circuit diagram of a preferred embodiment of the invention and illustrates essential portions of the control circuitry. The counter means 48 of FIGS. 1 and 2 is constituted by the

counter circuits

126, 128 and 130 which are connected to provide a 12- bit digital word at the

output conductors

132, 134, 136,

138, 140, 142, 144, 146, 148, 150, 152 and 154. Switching over from one encoder or pulse generating means to the other as for example from the pulse generating means 30 to the pulse generating means 301rof FIG. 1 is effected over two channels 156 and 158 to provide the appropriate clock inputs for the

counters

126, 128 and 130, as shown and counter reset is effected over the conductor 160 through the inverter 162. The two NAND gates 164 and 166 control the reset function for the counter means as will be described hereinafter. The circuitry includes three sets of

cross-coupled NAND gates

168, 170 and 172. The function of the gates 168 is to verify that an orientation means or marking is in fact a correct entity; the func tion of the gates 170 is to indicate the end of a verified marking; and the function of the gates 172 is to generate a reject signal if appropriate.

Input from the appropriate scanning means is effected through the

conductors

174 and 176 and provides one input to the NAND gate 178 such that in the presence of a dark background seen by the scanning means, indicative of the presence of a possible registration marking, the input at the conductor 180 to the gate 178 will go high and when there is a light background, the signal at the input 180 will be low. At the beginning of the cycle a mechanical switch is actuated energizing the conductor 182 which is applied to the pulse forming circuit 184 so that its output at the conductor 186 goes high very briefly, preferably in the order of 1.4 milliseconds. Correspondingly, the output at the conductor 188 goes from high to low to high for the purpose of inhibiting the gate 178 momentarily at the beginning of the cycle and to reset the three sets of

gates

168, 170 and 172 at their

respective inputs

190, 192 and 194 such that the normal conditions of these three sets of gates is that their outputs at 196, 198 and 200 are high whereas their outputs at 202, 204 and 206 are low.

Thus, as the cycle begins, the normal condition for the input to the NAND gate 164 is that its input at 208 is high and the initial inhibiting signal at the input 210 to the gate 178 will assure that its output at 212 and its corresponding input to the NAND gates 164 will also be high so that the output at 214 of the gate 164 is assured of being low correspondingly to assure reset of the

counters

126, 128 and 130. This condition also assures that the reset output at 214 of the gate 164 will be retained until such time as the presence of the possible registration mark is seen by the scanning means causes the input 212 to the gate 164 to go low and remove the reset output at 214. The counters can then begin to count and counting will continue until the registration or possible registration mark disappears from the view of the scanning means. If this condition occurs before a predetermined count is reached by the counters, as hereinafter described, the input at 180 to the gate 178 will go low and create a high output at 212 which again will establish the resetting signal at the conductor 214 to reset the counters and hold them reset at zero until another registration or possible registration mark comes into view of the scanning means.

The

bit output conductors

138, 144 and 146 of the

counters

126 and 128 are connected through an inverter 220 and an AND gate 222 to the base electrode of the transistor switch 224 so that a a predetermined count registered by the counter means, the transister 224 will become conductive to cause the voltage at the conductor 226 to go low. This low signal is applied as an input to the NAND gate 228 of the pair 168 and changes the state of this pair such that the output at 202 goes high whereas the output at 196 goes low. Remembering that the output at 198 of the pair 170 normally is high so that the corresponding input at 230 to the gate 166 is high, the described change of state of the pair 168 causes the other input 232 to the gate 166 to go high so that its normally high output at the conductor 234 goes low thus effecting reset of the

counters

126, 128 and 130. This reset signal will be held until the pair 170 changes state as hereinafter described to indicate the end of a verified registration mark whereupon the counter means may again begin counting the scan- 1 ning means input pulses.

The NAND gate 240 also has one input at 242 dependent upon the outputstate of the pair 168 and with the above described change of state thereof, the input at 242 goes high so that, subsequent to verification of the mark and as soon as the trailing edge of the mark is seen by the scanning means so that the other input at 244 goes high, the output of the gate 240 at 246 goes low. This low signal is applied as an input to the NAND gate 248 of the pair 170 and changes the output state of this pair such that the output at the conductor 204 goes high and that at the conductor 198 goes low. This change of state of the pair 170 produces the low signal at the output conductor 250 which inhibits or removes the output from the constant speed power source means 52 of FIGS. 1 and 2 thereby to prepare the system for normal stopping of the can in the properly registered position.

If, on the other hand, a false registration mark causes the input at 244 to the gate 240 to go from low to high indicative of the trailing edge of a mark, the other input at 242, being low because the pair 168 has not changed state, will prevent a change of state of the end point indicating gate pair 170.

At the beginning of the cycle .of operations, the timing circuitry 252 was actuated such that its output at the conductor 254 goes low for milliseconds.

When the output at 254goes high again, the two

pulse forming circuits

256 and 258 will produce high outputs at 260 and 262 for 1.4 milliseconds. Thus, if the end of a properly verified registration mark occurs before the cycle timing ends whereby the input 264 to the NAND gate 266 will be low, the momentary high input at the conductor 268 to the NAND gate 266 as effected by a pulse forming circuit 256 will have no effect on the output 270 of such gate 266 and the high input to the NAND gate 272 of the pair 172 will not be altered and this pair will not change state. Thus, the input 276 to the NAND gate 278 will remain high since this is the normal condition of the output 200 of the pair 172. At

the same time,'the two inputs at 280 and 282 of the NAND gate 284 will go high at the end of the timer period so that the normally high output at this gate will go low. Accordingly, if a registration mark has been verified and the end of this markis reached before the timing out occurs, both inputs at 276 and 286 of the gate 278 will be high so that its output at 288 at this point will go lowand this signal is used to permit the variable power source means 54 in FIGS. 1 and 2 to take over control of the drive to the appropriate work station.

If, on the other hand, no mark has been verified so that the circuit 168 does not change so that, correspondingly, the gate pair 170 cannot change state due to the output of the gate 240, the input at 264 to the NAND gate 266 will remain high so that the momentary input at the conductor 268 which occurs due to the pulse forming circuit 256 at the end of the timing pe riod will cause the input to the gate 272 of the pair 172 to go low thus to change the output state of the pair 172. Correspondingly, the output at 200 goes low thereby to inhibit the gate 278 and the output at 206 goes high so that the pulse forming circuit 290 produces a 1.4 millisecond low output pulse at its output conductor 292. correspondingly, a reject signal pulse is produced at the output conductor 294 and the NAND gate pair 172 changes state so that the signal appears at the output conductor 250 to remove the output fromthe constant power source means 52 of'FIGS. 1" and 2whereby the appropriate speedservoamplifier has no positive input and the platen of the appropriate work station rapidly will stop.

The circuit of FIG. 3 produces a further function which isachieved by the transistor switch 300 which is" associated withthe output bit conductor 154 of the counter130. This switch functions to reset the counter in the event that thedrive motor reverses rotation.

After the cycle initiation pulse has occurred, the mark verification is accomplished the first time that conduclated a number of pulses, sufficient for purposes of mark verification. The number of pulses is an arbitrary percentage of the total number of pulses in the registration mar k. In the example shown in FIG. 3 the number of pulses would be 200. If at the beginning of a registration cycle the shaft should momentarily reverse, conductors 132 thru 154 would immediately reach a high logic state (an inherent property of any reversible binary counter). This would create a false operational condition which would lead to an erroneous mark verification. To prevent the above false operational condition from influencing the logic circuitry, transistor 300 and the gate driving it were added. As a result whenever a reverse condition occurs prior to mark verification, the high tate at 154 turns 300 on, and subsequently prevents transistor 224 from conducting.

In a preferred embodiment, the can body shaper machine is a 440 cpm, l0 station machine each of which station is capable of re-shaping a cylindrically shaped can body. The re-shaping is accomplished by the expansion of the can walls against a surrounding mold through the action of an internally placed pressure bag. At the specified machine rate of 440 cpm, each of the 10 stations has a maximum of 270 milliseconds to scan the can, recognize the registration mark, and position the can. This 270 milliseconds is equal to one-fifth of the time required for the machines main turret to make one revolution so that, accordingly, two stations are registering cans simultaneously thereby requiring two complete registration logic systems 34 of FIG. 1, one for eachof 5 stations of the machine. Every milliseconds, one of the 10 machine stations passes through the machine reference point and the station registration start switch is actuated. At this point, the station has milliseconds to locate and verify the registration mark on the can. The actuated start switch resets the systems logic circuitry and applies a constant speed command to the stations drive motor which causes the platen and can to start accelerating to 1000 RPM and the encoder on the shaft 16 begins generating pulses at the rate of 2500 pulses per revolution. If at the beginning of the cycle the registration mark detector is not looking at the registration mark, the counter is in the reset mode the instant the scanner senses the leading edge of the mark, the counter reset is removed and encoder pulses are counted. If the registraton mark qualifies as a proper mark, it will be verified at which time the counter is reset and is held reset until the scanner senses the trailing edge of the verified mark. At the trailing edge of the mark, the counter starts to accumulate encoder pulse counts, the constant speed command is removed from the drive motor and the variable speed command from the comparator system becomes effective. The motor speed is now controlled asafunction of difference between the counter output and the stopping point memory or stopping point preset means 58 of FIGS. 1 and 2. The can registration process is completed when this difference and the motor speed are zero and the system is such that the stopping point error does not exceed i 1 encoder pulse. Thecan is held at this point by the servomotor and is then lifted up into the forming mold wherein the forming operation is performed with the can in the proper registry therewith.

If a can is upside-down'on its chuck, the scanner will not sense the registration mark so that when the scanning period timer times out, a misregistered or reject signal is triggered which is stored in a shift register memory and when the misregistered can reaches the machines reject.station, the machine control circuitry'will eject the misregistered can. I

As shown in FIG. 4, the stopping point memory or count means is provided with 5

input rows

302, 304, 306, 308 and 310 which are sequentially actuated and which form the input rows to a cross point matrix system. The 12-digit output bits are, present at the conductors 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 332, and 334 and each row is programmed as is necessary with the proper stopping point number by the insertion, selectively, of diodes such as that indicated by the reference character 336 across the individual cross points of the matrix. Since the 5 input rows 302-310 correspond to the 5 stations of the machine with which the logic circuitry 34 of FIG. 1 is associated as described above, each station may be programmed with the proper stopping point number which causes the correct registration of the can with the mold for such station. After the constant 1000 RPM command has been removed from the servoamplifier input from the means 52 of FIGS. 1 and 2, the variable speed command from the means 54 is effective, At this instant in the cycle, the can stopping point can be between 120 and 480 away, depending upon the particular station involved. At this instant also, because of the large difference in the zero count of the counter means 48 and the preset means 58 (typically the stop point count might be 2500 corresponding to a full revolution of the can) the output of the variable power source means 54 is in saturation and is at the same analog voltage level as the constant 1000 RPM speed signal from the means 52. Therefore, thecan will continue to rotate at 1000 RPM until the difference between the stopping point number and the counter output is within 1200 counts of each other. At this point, the output of the variable power source means comes out of saturation and becomes a function of the error count involved and the rapidly reducing output is fed to the input to the drive motor servoamplifier causing the motor to decelerate while rotating towards the stopping point.

What is claimed is: I. In a machine for performing a work operation on a can or like tubular body while the body is in a predetermined position, the body having circumferentially extending orientation means thereon, the combination of: e

a support for said body; drive means for rotating said support; scanning means positioned to look fixedly at said body for producing signals indicative respectively of the presence and absence of 'said orientation means as the body is rotated with respectto said scanning means; and control means for controlling said drive means to stop said support with said body in said predetermined position, said control means including pulse generating means connected with said support for generating a large number of pulses per revolution of said body, counter means for counting said pulses starting from a selected reference point of said orientation means, and variable power source means connected to said counter means and to said drive means for supplying said drive means with decreasing power in response to increasing count by said counter means. 2. In a machine as defined in claim 1 wherein said control means also includes constant speed power source means for normally supplying said drive means with power to rotate said support at a selected angular velocity, and means connected to said scanning means for disconnecting said drive means from said constant speed power source means when said scanning means detects said reference point of the orientation means.

means for generating a body reject signal in response to absence of orientation means verification.

5. In a machine having a support for rotating a can or like tubular body which is provided with circumferentially extending orientation means and drive means for rotating said support, the combination of:

scanning means fixed relative to said support and positioned to detect the presence and absence of said orientation means as said body is rotated;

pulse generating means actuated by said drive means for producing a large number of pulses per revolution of said support;

counter means connected to said scanning means for producing an output indicative of the pulses produced by the latter; verifying means connected to the output of said counter means for producing an output in response to a selected count reached by said counter means which is less than the total count required to sweep said orientation means past the scanning means;

end point means connected to said scanning means for producing an output in response to detection of the presence and then the absence of said orientation means;

timing means initiated at the beginning of a cycle for producing an output which is delayed by a period of time greater than that required to produce said total count when said support is rotating at a predetermined angular velocity;

power source means connected to said drive means for energizing the latter normally to rotate said support at said predetermined angular velocity;

gate means connected to the outputs of said verifying means and said end point means for terminating counting by said counter means when said output of the verifying means appears and for resuming counting by said counter means when said output of the end point means appears;

preset means for producing an output which is selected to correspond with a selected number of said pulses;

comparison means connected to the outputs of said counter meansand of said preset means for decreasing the output of said power source means to zero when said counter means reaches a count corresponding to said selected number of pulses to which the output of said preset means corresponds; and

rejection means connected to the outputs of said timing means and said verifying means for alternativley producing a reject signal when said verifying means does not output by the time said output appears from said timing means and a control signal when said verifying means does output by the time said output appears from said timing means, said power source means being enabled to produce said decreasing output in response to generation of said control signal.

6. In a machine as defined in claim 5 wherein said power source means comprises a constant speed power source which is disabled in response to output by said end point means, and a variable power source which is enabled by said control signal.

7. In a machine as defined in claim 6 wherein said gate means functions to exclusively monitor the outputs of said verifying means and said end point means, and said counter means in reset by said gate means;

8. In a machine for performing-embossing and like operation on a tubular body such as a can, said machine having a main turret and at least two work stations mounted on the main turret, each work station including a platen for rotating a tubular body into a regis-' tered position which may be unique for each station and a drive motor for rotating the platen, the combination of;

encoder means at each of said two work stations for generating a large number of pulses per revolution of the associated platen; tachometer means at each of said two work stations for generating a negative feedback signal related to the rotational speed of the associated platen; scanning means at each station for detecting the presence and absence of registration marking on a tubular body associated with the associated platen; and registration control circuitry for effecting registration sequentially at said two work stations; said registration control circuitry including station selection means for selectively switching the outputs of said encoder means,.and said scanning means to the control circuitry; cycle start switch means for initiating cycling of the control circuitry in response to predetermined positions of the main turret;

counter means for counting pulses from an encoder means; preset count means for controlling the stopping point of a platen; count comparator means connected to said counter means and said preset count means for producing a drive motor positive signal output dependent upon the count difference determined by the comparator means; and end point means for starting count by said counter means in response to detection of the presence and then the absence of a registration marking by said scanning means.

9. In a machine as defined in claim 8 wherein the registration control circuitry also includes timing means for allowing verification of a registration marking.

10. In a machine as defined in claim 9 wherein said registration control circuitry further includes constant speed drive means for rapidly accelerating a platen to a predetermined speed at the beginning of each cycle and means for disabling such constant speed drive at the end of the period produced by said timing means.

absence of verification within the timing period.

Claims

1. In a machine for performing a work operation on a can or like tubular body while the body is in a predetermined position, the body having circumferentially extending orientation means thereon, the combination of: a support for said body; drive means for rotating said support; scanning means positioned to look fixedly at said body for producing signals indicative respectively of the presence and absence of said orientation means as the body is rotated with respect to said scanning means; and control means for controlling said drive means to stop said support with said body in said predetermined position, said control means including pulse genErating means connected with said support for generating a large number of pulses per revolution of said body, counter means for counting said pulses starting from a selected reference point of said orientation means, and variable power source means connected to said counter means and to said drive means for supplying said drive means with decreasing power in response to increasing count by said counter means.

2. In a machine as defined in claim 1 wherein said control means also includes constant speed power source means for normally supplying said drive means with power to rotate said support at a selected angular velocity, and means connected to said scanning means for disconnecting said drive means from said constant speed power source means when said scanning means detects said reference point of the orientation means.

3. In a machine as defined in claim 2 wherein said control means further includes means for connecting said variable power means to said drive means in response to verification of the presence of said orientation means by said scanning means.

4. In a machine as defined in claim 3 including reject signal generating means connected to said scanning means for generating a body reject signal in response to absence of orientation means verification.

5. In a machine having a support for rotating a can or like tubular body which is provided with circumferentially extending orientation means and drive means for rotating said support, the combination of: scanning means fixed relative to said support and positioned to detect the presence and absence of said orientation means as said body is rotated; pulse generating means actuated by said drive means for producing a large number of pulses per revolution of said support; counter means connected to said scanning means for producing an output indicative of the pulses produced by the latter; verifying means connected to the output of said counter means for producing an output in response to a selected count reached by said counter means which is less than the total count required to sweep said orientation means past the scanning means; end point means connected to said scanning means for producing an output in response to detection of the presence and then the absence of said orientation means; timing means initiated at the beginning of a cycle for producing an output which is delayed by a period of time greater than that required to produce said total count when said support is rotating at a predetermined angular velocity; power source means connected to said drive means for energizing the latter normally to rotate said support at said predetermined angular velocity; gate means connected to the outputs of said verifying means and said end point means for terminating counting by said counter means when said output of the verifying means appears and for resuming counting by said counter means when said output of the end point means appears; preset means for producing an output which is selected to correspond with a selected number of said pulses; comparison means connected to the outputs of said counter means and of said preset means for decreasing the output of said power source means to zero when said counter means reaches a count corresponding to said selected number of pulses to which the output of said preset means corresponds; and rejection means connected to the outputs of said timing means and said verifying means for alternatively producing a reject signal when said verifying means does not output by the time said output appears from said timing means and a control signal when said verifying means does output by the time said output appears from said timing means, said power source means being enabled to produce said decreasing output in response to generation of said control signal.

7. In a machine as defined in claim 6 wherein said gate means functions to exclusively monitor the outputs of said verifying means and said end point means, and said counter means is reset by said gate means.

8. In a machine for performing embossing and like operation on a tubular body such as a can, said machine having a main turret and at least two work stations mounted on the main turret, each work station including a platen for rotating a tubular body into a registered position which may be unique for each station and a drive motor for rotating the platen, the combination of: encoder means at each of said two work stations for generating a large number of pulses per revolution of the associated platen; tachometer means at each of said two work stations for generating a negative feedback signal related to the rotational speed of the associated platen; scanning means at each station for detecting the presence and absence of registration marking on a tubular body associated with the associated platen; and registration control circuitry for effecting registration sequentially at said two work stations; said registration control circuitry including station selection means for selectively switching the outputs of said encoder means, and said scanning means to the control circuitry; cycle start switch means for initiating cycling of the control circuitry in response to predetermined positions of the main turret; counter means for counting pulses from an encoder means; preset count means for controlling the stopping point of a platen; count comparator means connected to said counter means and said preset count means for producing a drive motor positive signal output dependent upon the count difference determined by the comparator means; and end point means for starting count by said counter means in response to detection of the presence and then the absence of a registration marking by said scanning means.

11. In a machine as defined in claim 10 wherein said registration control circuitry also includes reject signal generating means for producing a reject signal in the absence of verification within the timing period.