US3785470A

US3785470A - Single commutation vertical wheel marking machine

Info

Publication number: US3785470A
Application number: US00356732A
Authority: US
Inventors: R Schacht
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-05-03
Filing date: 1973-05-03
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15

Abstract

A marking wheel for marking metal or plastic tags and the like employing a rotary marking wheel having marking characters on the periphery which is continuously rotated and, upon depressing of an appropriate key upon a keyboard, is caused to stop. Marking is established by the raising of a worktable driven through a magnetic clutch to engage the tag with the marking wheel. The clutch in stopping of the continuously rotating marking wheel is activated by an electrical circuit which comprises a segment of a commutator stator on a printed circuit board which completes the circuit upon being contacted by a continuously driven rotor. The circuit employs a silicon control rectifier for extremely rapid completion of the electrical circuit upon the depression of the desired key on the keyboard. The completion of the circuit through the appropriate segment on the commutator further actuates a pawl to engage the appropriate ratchet tooth on a ratchet wheel keyed to the shaft of the marking wheel to stop the marking wheel for the marking operation.

Description

llnited States Patent [191 Schacht SINGLE COMMUTATION VERTICAL WHEEL MARKING MACHINE [76] Inventor: Roy Arthur Schacht, 744 Des Peres Rd., St. Louis, Mof63l3 l 7 V v [22] Filed: May 3, 1973 [21] Appl. No.: 356,732

Related 1.1.8. Application Data 63] Continuation of Ser. No. 148,463, June 1, 1971,

abandoned.

[52] US. Cl 197/6.4, 197/49 [51] Int. Cl B41j 1/22 [58] Field of Search 197/49, 6.4, 6.5,

[56] References Cited UNITED STATES PATENTS 2,664,985 1/1954 Schacht l97/6.5

3,232,404 2/1966 Jones 197/49 3,227,258 1/1966 Pannier et al.. l97/6.6

3,589,494 6/1971 Gloess 197/49 X 3,330,397 7/1967 Schwartz et a1. l97/6.7

3,306,416 2/1967 Dahlin et a1. l97/6.6

Rudisch et al. l9-'7/6.6

[451 Jan. 15, 1974 Primary ExaminerRobert E. Pulfrey Assistant Examiner--R. T. Rader AttorneyGlenn K. Robbins [57] ABSTRACT A marking wheel for marking metal or plastic tags and the like employing a rotary marking wheel having marking characters on the periphery which is continuously rotated and, upon depressing of an appropriate key upon a keyboard, is caused to stop. Marking is established by the raising of'a' worktable driven through a magnetic clutch to engage the tag with the marking wheel. The clutch in stopping of the continuously rotating marking wheel is activated by an electrical circuit which comprises a segment of a commutator stator on a printed circuit board which completes the circuit upon being contacted by a continuously driven rotor. The circuit employs a silicon control rectifier for extremely rapid completion of the electrical circuit upon the depression of the desired key on the keyboard. The completion of the circuit through the appropriate segment on the commutator further actuates a pawl to engage the appropriate ratchet tooth on a ratchet wheel keyed to the shaft of the marking wheel to stop the marking wheel for the marking operation.

6 Claims, IODrawing Figures PATENTEBJAN I 5 I974 sum aur SINGLE COMMUTATION VERTICAL WEEI. MARKING MACHINE This is a continuation of application Ser. No. 148,463, filed June l, 1971 now abandoned.

SUMMARY OF THE INVENTION In the past, various types of marking wheels have been devised for physically imprinting on metal or plastic tags and the like. One such marking wheel has been shown in my U.S. Pat. No. 2,664,985 which uses a rotary marking or imprinting wheel with characters on the periphery of the wheel which are caused to print against a work piece raised into printing relation by a reciprocal work table. The continuously rotating marking or printing wheel is stopped in the printing operation by the engagement of an electromagnetically operated pawl against a ratchet wheel keyed to the shaft of the printing wheel. Such wheels as my prior marking machine shown in US. Pat. No. 2,664,985 required two solenoid operated pawls because the relay electrical system could not be devised to be fast enough to operate with a single pawl on the ratchet wheel.

By means of this invention, there has been provided an improved marking wheel in which the electrical system utilizes a printed circuit board and a direct current circuit utilizing a silicon control rectifier, i.e. SCR which is energized by a small voltage such as two volts established when a marking key is depressed. Depression of the key sends a signal out to a commutator segment of the printed circuit commutator stator to the gate of the SCR which is tripped to establish current to the magnetic actuator for actuating the pawl to stop the ratchet wheel and the associated printing wheel and also to actuate a clutch actuator to turn the work table shaft one revolution. The operation of the clutch connects the shaft to the motor to move a rotary cam against the work table to raise and lower it in the aforesaid cycle and revolution. By the utilization of the printed circuit commutator and the SCR control circuit the switching speed is greatly increased while space and maintenance requirements are greatly decreased.

The control circuit established'by this invention is extremely rapid in response and a single pawl can be employed with a single ratchet wheeel whereas with my 1 prior machine, one tooth of the ratchet was used for every two characters and twomagnetic actuators and pawls were required to be employed. Thus half as many teeth on the ratchet wheel were employed as the characters on the marking wheel on the machine which gave more space and allowed the actuator more time to fall in place to stop the ratchet wheel. Thus by the instant invention with the more rapid response, through the improved electrical system provided, the speed of operation is greatly multiplied and, as an example, works about four times as fast.

Further, by the instant invention and the improved electrical circuit, protective circuits are employed to prevent the back voltage from the magnetic pawl actuator and the magnetic clutch solenoid actuator from establishing damaging voltages through the silicon control rectifier and the direct current rectifier. Such a circuit is also employed in the de-energizing switch.

In addition, a condenser circuit is employed to provide a charge when an operator provides only a light touch or momentary depressing of the key before the rotor and the commutator establish contact with the associated commutator segment. This charge, when contact is ultimately made by the rotor with the segment, triggers the circuit to tire or trip the gate to the SCR to establish the actuating circuit just as if a long touch were employed on the marking keys.

The electric circuit uses direct current provided by the direct current rectifier and the silicon control rectifier so that the keyboard control circuit operates at a very low voltage. Actually the keyboard simply keys or triggers the gate of the SCR which in turn handles the higher voltages required to operate the magnetic actuators for the ratchet wheel and the clutch. The SCR once gated, continued to pass current to the magnetic actuators until the completion of the marking cycle effected by the operation of the de-energizing switch which is operated by a lobe in the cam shaft associated with the work table to break the load circuit momentarily, and to set up the circuit for another marking operation.

The machine, through the electrical circuit provided, can be controlled by a tape or card reader and a translator connected so as to read the card or tape and send the signals read into the translator where they will be translated into a single impulse which can be directed to the actuators of the machine through the various segments of the commutator.

The above features are objects of this invention and further objects will appear in the detailed description which follows and will be otherwise apparent to those skilled in the art.

For the purpose of illustration, there is shown in the accompanying drawings a preferred embodiment of the instant invention. It is to be understood that these drawings are for the purpose .of example only and that the invention is not limited thereto.

IN THE DRAWINGS FIG. 1 is a view in side elevation taken from the left side of the machine;

FIG. 2 is an enlarged fragmentary view in rear elevation of the machine;

FIG. 3 is a view in cross-section taken on the line 3-3 of FIG. 1;

FIG. 4 is a view in section taken on the line 44 of FIG. ll;

FIG. 5 is a top plan view ofthe printed circuit board used on the commutator;

FIG. 6 is a bottom plan view of the printed circuit board;

FIG. 7 is an enlarged fragmentary top plan view of the rear of the machine showing the printed circuit board and rotor cage attached to the marking wheel shaft;

FIG. 8 is a view in cross section taken on the line 88 of FIG. 7;

FIG. 9 is a view in section taken on the line 99 of FIG. 8 showing the rotor wiper blade in contact with one of the commutator segments; and

FIG. 10 is a schematic diagram of the electrical circuit employed for the marking machine.

DESCRIPTION OF THE INVENTION The marking wheel of this invention generally identified by the reference numeral 20 in. FIG. 1. It is com- The printing wheel 24 as well as the work table and keyboard are the same general construction as described in my aforesaid U.S. Pat. No. 2,664,985. Thus the printing wheel 24 has printing characters 30 associated on its periphery and the wheel is driven by a shaft 32 connected to a ratchet wheel 34 and to the motor through a friction clutch and driven by pulley belt 35. A magnetically operated pawl 36 is adapted to engage the teeth of the ratchet wheel and stop the wheel against the force of friction clutch 38. The pawl is actuated by a solenoid 40.

The work table 26 is pivotally supported from the machine by a yoke. 42 and is adapted to be raised and lowered by the revolution of rotary cam 44 which contacts a thrust bar 45 at the bottom of the table. The cam 44 is connected to the cam shaft 46 which is driven only one revolution in the marking operation by means of clutch 48 connected to the motor and which is actuated by clutch actuator 50 operated by solenoid S2.

A de-energizing switch to de-energize the circuit and signal the completion of the single revolution of the cam shaft and marking operation is best shown in FIG. 3 where a contact button switch 54 is shown in juxtaposition to the cam 444.

The aforementioned components are identical in construction with the printing wheel and work table and actuating mechanism described in my aforementioned U.S. Pat. No. 2,664,985.

The control circuit for my marking wheel is provided by a printed circuit board 60 best shown in FIGS. 4 through 8. This printed circuit board houses the commutator segments in a stator 62 and a rotor 64 supported by a rotor cage 66 having a support hub 67 on one side of the printed circuit board and a support cage 68 on the reverse side of the circuit board. The rotor cage and support cage are in the form of shallow dishshaped support members which are connected to one another through the circuit board by bolts and are of transparent plastic so that the operation and contact with the rotor with the commutator segment can be easily read and inspected for registration and adjustment.

Each of the commutator segments is connected by a printed circuit lead 69 to a buss bar 70 with approximately one-half of the commutator segment leads being shown on the top of the printed circuit board and the remaining half being shown on the reverse side.

A connecting sleeve 72 fits frictionally over the buss bar 70 so that leads can be connected to the appropriate keys 74 on the switchboard, each one associated with a commutator segment. The keys are conventional normally open keys of the same type as generally disclosed in my prior U.S. Pat. No. 2,664,985 and, upon being depressed, close through a spring-operated switch a circuit between the key and the printed circuit to the associated commutator segment so that, as will later be described, when the rotor contacts the associated commutator segment, a firing circuit is provided into the SCR to establish energizing circuit to the coils of the magnetic actuators for the ratchet wheel pawl and cam shaft clutch.

The electrical circuit is shown schematically in FIG. 9. Alternating current is provided to the circuit through leads 80 and 82 and through an on-off switch 84 is introduced to rectifier bridge 86 consisting of four silicon diodes through leads 88 and 90. A resistor 92 of 130 ohms acts as a current limiting resistor to minimize the danger of voltage surges to the silicon rectifier and the silicon diodes of the rectifier bridge.

The rectifier bridge is connected by lead 94 to the common buss bar 70. This buss bar is connected to the individual circuit leads to the individual keys 74 on the keyboard which, as aforementioned, are in the normally open position and upon being depressed establish a circuit to the commutator segments 62 on the printed circuit board. The rotor 64 is connected to a voltage divider consisting ofa 7.5 K resistor 96 and a l K resistor 98. As the common post 100 a lead 102 takes off two volts to the gate of the silicon control rectifier 104. This rectifier is connected by leads 106 to post 108 which, in turn, is connected by lead 110 to resistor 98. The silicon control rectifier establishes a higher voltage circuit by lead 112 to the magnetic pawl actuator for the ratchet wheel through solenoid 40 and is connected in series through lead 114 to the solenoid 52 for the cam shaft clutch actuator 50. The circuit is in series with the de-energizing switch 54 which is normally closed but is momentarily opened at the completion of the single cycle movement of the work table to signal the end of the marking operation.

In order to provide a protective means for the silicon control rectifier from the high back voltage from the coils for the magnetic pawl actuator and the cam shaft actuator, a resistor 116 and condenser 118 and diode 120 are provided. This establishes a protective circuit to prevent high back emf voltages from damaging the silicon control rectifier. This circuit functions much in the nature of an arc suppressor switch.

Likewise for the de-energizing switch 54 a protective device in the form of condenser 120 and resistor 122 connected across the de-energizing switch are provided. Thus, where a large back surge of voltage is established through the coils instead of jumping across the contacts of the de-energizing switch, the condenser absorbs this voltage and leaks it out slowly through the resistor.

A condenser 124 is connected across the keys to provide a safety circuit to insure firing of the silicon control rectifier where the operator only momentarily depresses the marking key 74. In such a case where an extremely light touch is employed, which is not long enough for the rotor to establish contact with the keys associated commutator segment, the condenser establishes an electrical charge so that when the contact is established, there will be some energy which discharges to complete the circuit to the gate of the SCR to provide operation of the magnetic actuator for the ratchet wheel pawl and the cam shaft clutch to effect the marking operation.

OPERATION The marking wheel of this invention is simply operated by first closing the on-off switch 84. This provides a source of power to the electrical circuit to drive the rotary marking wheel 24 and to operate the work table 26 which raises and lowers the work piece into contact with the marking wheel to perform the marking operation upon the work piece such as a tag, metal emblem or other material to be physically marked.

The rotary marking wheel is provided with the various marking characters 30 in its periphery corresponding to letters of the alphabet, punch code characters and symbols, and the like, revolves constantly until it is stopped for the marking operation. It is driven through the friction or slip clutch 38 until an electrical signal is pulsed by operation of the keyboard 28 through a corresponding stator segment 62 of the commutator on the printed circuit board. The rotor 6 of the commutator establishes a circuit when it passes over the segment of the commutator corresponding to the depressed key 74 to actuate the marking wheel ratchet wheel 34 by means of an electromagnetic pawl 36 which engages the appropriate tooth of the ratchet wheel fastened to the printingwheel shaft. The engagement of the ratchet wheel by the magnetic pawl stops the character wheel at the proper printing character in marking position.

The depressing of the key also actuates the cam shaft

clutch actuator

50, 52 to connect the cam shaft 46 as sociated with the work table which is driven on revolution per mark by the motor acting through the magnetic clutch. This causes the work table to be raised to apply pressure between the marking wheel and the work to perform the marking operation. it will be understood that instead of raising 'andlowering the work table the magnetic actuator and cam shaft may be used to lower and raise the printing wheel.

The keyboard employed has normally open switches associated with each of the marking keys which are connected by leads 69 to commutator segments 62 corresponding to the appropriate'ratchet tooth and marking character on the marking wheel so that when the desired key is depressed current is directed through the commutator to the magnetic ratchet wheel actuator solenoid 40 and the cam shaft magnetic clutch solenoid 52 for the work table causing the wheel to stop with the key selected stamp in the marking position. This circuit also causes the cam shaft to revolve, which elevates the work table, pressing the work and the marking wheel together. As the cam shaft continues to revolve the cam the closing of the main on-off switch 8d. This is conventionally actuated from the keyboard and connects the segments 62 of the commutatorwith the positive side of the DC supply provided by lead 94- through the rectifier. Each key, as shown in the drawing, is connected with a different segment of the commutator stator on the printed circuit board, some being shown connected to segments on one side of the board and the others being connected to segments on the reverse side of the board to make full utilization of space. The commutator, for purpose of example, may be rotating at 173 RPM and faster and, as the rotor blade 64 wipes over the segments, it establishes a circuit upon the depressing of the appropriate key 74m complete the circuit. This circuit is established through the voltage divider composed of resistor 96 and resistor 98 to provide a low voltage such as 2 volts to the gate of the SCR 104. When the gate of the SCR is energized by the low voltage from the voltage divider, it passes current from the positive side through the normally closed deenergizing switch 54 and through the cam shaft clutch actuator solenoid 52 for the work table drive shaft and the solenoid 52 for the ratchet wheel actuator. The energization of this clutch causes a single revolution of the cam shaft to raise and lower the worktable through the energizing coil of the magnetic actuator which actuates the clutch lever 56 to cause the connection of the clutch to the motorv shaft.

The marking wheel actuator is connected in series with the magnetic clutch actuator and through the solenoid coil 40 in the marking wheel actuator causes the pawl 36 to engage the ratchet wheel 34 connected to the printing wheel shaft and stop the marking wheel with the appropriate marking character in printing position to perform the printing operation when the work table is raised.

As the cam shaft 46 completes its one-cycle revolution, it causes the engagement of a pin that momentarily opens the normally closed deenergizing switch 54 which deenergizes and opens the circuit to both the marking wheel actuator and cam shaft clutch actuator to complete the marking operation. The machine is then ready for the next marking operation upon the depressing of the desired key on the keyboard.

The source of direct current is provided by the rectifier bridge 86 consisting of four silicon diodes. The rectifieris connected to a resistor 92 in series on the AC lead to provide a current limiting factor to the SCR and the rectifier to prevent blowout-caused by voltage surges. The resistor 116 and condenser 118 and diode 119 provide a protective circuit to protect the SCR from high back emf voltages from the coils of the marking wheel actuator and the cam shaft clutch actuator from surges of power that might otherwise blow out or cause damage to these components. They operate much in the fashion of an arc suppressor across a switch to minimize the effect of high inductive loads to prevent arcing across the contacts. The coils of the marking wheel actuator and theactuator for the magnetic clutch have relatively high reverse voltages when the circuit is shut off and the protection afforded minimizes the damaging effect of these voltages.

A condenser 120 and resistor 122 are also connected across the deenergizing switch 54. to provide a protective circuit for the switch. A back-surge of voltage instead of jumping across the contact so the energizing switch will be absorbed by the condenser and then leaked out slowly through the resistor to provide protection for the switch, much in the same fashion as described above, for the SCR and rectifier.

The condenser 1124 is provided to establish a charge whenever the operator touches a key. As the wiper blade on the commutator comes in contact with the segment corresponding to the depressed key, the condenser has .a charge waiting for it and this will be picked up right away. Thus, in the case where operators depress a key only momentarily, and before the wiper blade comes around to complete a circuit with the associated commutator segment, thezoperator may have already released the key so there is no circuit established. With the provision of the condenser connected across the contact by the key, a charge is provided so that discharge can be effected through the segment corresponding to the depressed key when the wiper blade rotor establishes contact to energize the circuit through the SCR. By the provision of this condenser, the socalled light touch operator difficulty has been obviated. At the faster speeds of rotation of the wiper blade rotor, the light touch problem is minimized but, in any event, the provision of the condenser obviates this problem.

Various changes and modifications may be made in this invention, as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

1. in a marking machine having a rotating marking wheel with marking characters provided at the periphery of the wheel and a work table carrying a work piece, means for vertically moving the work table by raising it into marking position when said wheel is in a stopped position, and a control means for controlling the stopping of said marking wheel in selected marking positions, said control means being provided with individual marking circuits connected to segments of a commutator stator, said commutator having a rotor adapted to wipe said segments and actuate an electromagnetically operated pawl engageable in selected ratchet teeth on a ratchet wheel to stop said marking wheel in a selected marking position corresponding to the selected key, the improvement comprising means for providing a direct current to said individual marking circuits provided by the depressing ofa key to a silicon control rectifier to energize a magnetic actuator to actuate said pawl to engage the ratchet wheel to stop the marking wheel and to energize a separate magnetic actuator to actuate said vertical moving means, the

commutator stator being in the form of a printed circuit.

board of rigid material and having individual printed circuit leads on both sides of the board terminating in a buss bar formed as a tab extension on the board, said buss bar removably receiving a cable sleeve fitting over said tab-extension and provided with circuit leads registering with the individual printed circuit leads and communicating with switchboard keys provided in the control means, and said commutator segments being formed by an electrically conductive layer material printed on the board.

2. The marking wheel of claim 1 in which condenser means are provided to hold an electrical charge upon momentary depressing of a selected marking key provided in the control means before the rotor contacts the associated commutator segment to fire the silicon control rectifier when said rotor at a later time makes contact with said segment.

3. The marking wheel of claim 1 in which the rotor is joumaled in a transparent plastic cage on one side of the board providing for visual inspection of the rotor with the commutator segments and the opposite side of the board is provided with a support cage having means connecting it to the rotor cage providing stability against bending of the printed circuit board.

4. The marking wheel of claim 3 in which the aforementioned cages are generally dish-shaped and enclose the commutator segments for protection thereof.

5. The marking wheel of claim 1 in which the rotor is connected to voltage divider means to provide a low voltage to the silicon control rectifier upon the completion of a circuit established by the control means.

6. The marking wheel of claim 1 in which said rotor is connected to voltage divider means to provide a low voltage to the silicon rectifier upon the completion of a circuit established by the depression of a selected marking key provided in the control means, condenser means being provided to hold an electrical charge upon momentary depressing of a key before the rotor contacts the associated commutator segment to fire the silicon control rectifier when said rotor at a later time makes contact with said segment, said rotor being journaled in a transparent plastic cage on one side of the board providing for visual inspection of the rotor with the commutator segments, and a support cage having means connecting it to the rotor cage providing stability against bonding of the printed circuit board, said cages being generally dish-shaped to enclose the commutator segments for protection thereof.

Claims

1. In a marking machine having a rotating marking wheel with marking characters provided at the periphery of the wheel and a work table carrying a work piece, means for vertically moving the work table by raising it into marking position when said wheel is in a stopped position, and a control means for controlling the stopping of said marking wheel in selected marking positions, said control means being provided with individual marking circuits connected to segments of a commutator stator, said commutator having a rotor adapted to wipe said segments and actuate an electromagnetically operated pawl engageable in selected ratchet teeth on a ratchet wheel to stop said marking wheel in a selected marking position corresponding to the selected key, the improvement comprising means for providing a direct current to said individual marking circuits provided by the depressing of a key to a silicon control rectifier to energize a magnetic actuator to actuate said pawl to engage the ratchet wheel to stop the marking wheel and to energize a separate magnetic actuator to actuate said vertical moving means, the commutator stator being in the form of a printed circuit board of rigid material and having individual printed circuit leads on both sides of the board terminating in a buss bar formed as a tab extension on the board, said buss bar removably receiving a cable sleeve fitting over said tab-extension and provided with circuit leads registering with the individual printed circuit leads and communicating with switchboard keys provided in the control means, and said commutator segments being formed by an electrically conductive layer material printed on the board.

3. The marking wheel of claim 1 in which the rotor is journaled in a transparent plastic cage on one side of the board providing for visual inspection of the rotor with the commutator segments and the opposite side of the board is provided with a support cage having means connecting it to the rotor cage providing stability against bending of the printed circuit board.

4. The marking wheel of claim 3 in which the afore-mentioned cages are generally dish-shaped and enclose the commutator segments for protection thereof.