US3474298A

US3474298A - Circuit for controlling drive of rotating machine

Info

Publication number: US3474298A
Application number: US637748A
Authority: US
Inventors: Edward M Tellerman
Original assignee: Stop Motion Devices Corp
Current assignee: Stop Motion Devices Corp; IRO Inc
Priority date: 1967-05-11
Filing date: 1967-05-11
Publication date: 1969-10-21
Anticipated expiration: 1986-10-21
Also published as: GB1150825A; DE1588851A1

Description

Oct. 21, 1969 CIRCUIT FOR CONTROLLING DRIVE OF ROTATING MACHINE E. M. TELLERMAN Filed May 11, 1967 70 51-0 Mot/an Power Pack l 6 5Q 50L J24 INVENTOR. Edward filkrmafi BY 6% 2 A TTO/P/VIKS United States Patent US. Cl. 317148.5 8 Claims ABSTRACT OF THE DISCLOSURE The disclosure relates to a control circuit for controlling the drive of a rotating machine. Such control circuit provides for the performance of three basic functions, namely, the starting of the knitting machine for continuous normal operation, the rotation of the machine for finite amounts under manual pushbutton control, and the rotation of the machine for a finite predetermined fixed amount which is electronically controlled and of such :small magnitude as to be incapable of being obtained under manual pushbutton control. The last mentioned function is the principal aspect of the disclosure, and of the invention, and is accomplished by providing a circuit path including a transistor amplifier with the current flow through such circuit path being the amplified current obtained by triggering the transistor. Said circuit path is operative, when de-energized, to interrupt the rotation of the machine, and such de-energization is the result of a blocking voltage generated in response to the rotation of the machine itself, which voltage is effective to block the flow of triggering current for the transistor amplifier.

BACKGROUND OF THE INVENTION Modern day knitting machines are usually equipped with automatic means for stopping the machine when a fault in the knitting occurs. These means are commonly known as stop motions and are adapted to instantaneously detect knitting faults such as yarn breakage, unusual variations in yarn tension, holes in the fabric, all of which must be detected as soon as possible and cause the machine to stop. Examples of stop motions of the type referred to above are shown in Patents Nos. 2,921,546, 3,257,518, and others assigned to the assignee hereof. Detection of the knitting fault by the stop motion must result in a cutoff of the drive motor for the knitting machine as fast as is possible and such can be accomplished by the use of a power pack having electronic control circuitry, such as described in copending patent application Ser. No. 349,418, filed Mar. 4, 1964, now Paent No. 3,343,158, and assigned to the assignee hereof.

After the knitting fault is detected by the stop motion which through the medium of the power pack causes a substantially instantaneous cutoff of the knitting machine drive motor, the cause of the defect is corrected thereby restoring the machine into condition for resumed normal operation. Before bringing the machine to its normal knitting speed, it is highly desirable, if not mandatory, to rotate the knitting machine for finite short periods of time in order to make a thorough examination of the machine before normal operation is resumed. It therefore becomes important to provide control means whereby the knitting machine can perform several functions, namely, (1) resume normal rotational speed for normal knitting operation, (2) be rotated in response to pushbutton depression for the time interval of such depression, and (3) be rotated for a finite amount, the magnitude of which is so small (a few needles) that such cannot be accomplished by manual pushbutton operation, with dependability.

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SUMMARY OF THE INVENTION In accordance with the present invention, a control for the knitting machine drive is provided whereby (1) the operation of the drive can be resumed for normal operation of the knitting machine by depression of a start button, (2) the knitting machine can be rotated for finite amounts manually controlled by depression of a jog button, and (3) the knitting machine can be rotated for finite predetermined fixed amounts, electronically controlled in response to the depression of an inch button.

The last mentioned feature obtained by the inch button is the most significant aspect of the invention, as the starting and jogging functions, as such, may have been previously used, although not in association with circuitry which also includes the inching function.

Brief description of the drawing The drawing represents a schematic circuit diagram of the drive control in accordance with the invention.

Description of the preferred embodiment Referring now to the drawing, there is shown circuitry C of the knitting machine drive control in accordance with the invention. Essentially, the control is operated by four pushbuttons, namely, normally open start button 10, normally open jog button 12, normally open inch button 14, and normally closed stop button 16. Power for the operation of the control circuitry is obtained through terminals 1818 which are connected across a source of AC which is normally the secondary of a transformer already available in association with the knitting machine in connection with the aforediscussed power pack for the stop motion. Solenoid 20 is associated with the stop motion power pack and is of pertinency herein only insofar as it controls the power supply to the control circuitry C. More specifically, solenoid 20 is energized only when the stop motion has detected a defect and has stopped the machine. Under such conditions, solenoid 20 is operative to close contacts 22 and 24, leaving contact 26 open and interrupting all power supply to the control circuitry. The necessity for this is obvious since the knitting defect which activated the stop motion should be repaired before the machine is permitted to be reactivated. Accordingly, solenoid 20 acts as a safety to prevent the operation of the drive until the defect has been corrected and the knitting machine has been restored to what is believed to be its normal condition. Solenoid 29, as well as all the other solenoids in the drawing, and their associated contacts, are shown in the condition they are in when the solenoids are unenergized. It will be noted that when solenoid 20 is energized, closing contacts 22 and 24, lamp 28 is lit to provide a visual indication that the knitting machine is not ready for normal operation. It is only upon restoration of the knitting machine to its normal condition that solenoid 20 will be de-energized, closing

contacts

22 and 26 and opening contact 24.

The AC power provided across terminals 18-48 is impressed across full wave rectifier 30, consisting of

diodes

32, 34, 36 and 38, so as to provide DC to control circuitry C across

terminals

40 and 42.

Solenoid 46 controls contacts 48 and 50 which, when closed, complete the necessary circuitry to energize the knitting machine drive motor. In the drawing, solenoid 46 is shown in unenergized condition, with the

associated contacts

48, 50 being open. It will be understood that the conductors leading from

contacts

48, 50 do not necessary lead directly to the drive motor itself but could instead lead to a clutch control which, upon closing of

contacts

48, 50, is operative to couple the knitting machine with the drive motor. It will be understood that solenoid 46 could itself be the instrumentality to directly couple the knitting machine to the drive motor, in which

event contacts

48 and 50 would not be necessary.

OPERATION OF THE START BUTTON Upon closing of start button 10, a complete circuit can be traced from terminal 40, terminal 52, solenoid 54, terminal 56, terminal 58, closed start button 10, terminal 60, terminal 62, normally closed stop button 16, terminal 64, and terminal 42. The closing of start button also completes a circuit from terminal 40 through terminal 52, terminal 66, terminal 68, solenoid 46, terminal 70, terminal 72, one-way diode 74, terminal 58, start button 10, terminal 60, terminal 62, stop button 16, terminal 64, and terminal 42. Such closing of start button 10 energizes solenoid 46 which in turn closes

contacts

48, 50 to energize the drive motor. The energization of solenoid 54 closes

contacts

76 and 78 to provide a holding circuit for the start button. Accordingly, once the start button is pushed, the knitting machine will be activated and remain in such condition even though the start button 1s released, by virtue of the holding circuit. The only way in which the drive motor can be stopped, after it has been started, is either by pushing stop button 16 which will interrupt the circuitry through solenoid 46, or by activating the stop motion which will energize solenoid 20,

open contacts

22, 26, and interrupt all power to circuitry C. One-way diode 80 is for the purpose of counteracting the back -E.M.F. which may be created by the de-energization of solenoid 46 across which it is connected.

OPERATION OF THE IOG BUTTON Upon closing of jog button 12, a complete circuit can be traced from terminal 40, terminal 52, terminal 66, terminal 68, solenoid 46, terminal 70, terminal 72, closed jog button 12, terminal 62, normally closed stop button 16, terminal 64, and terminal 42. The completion of such circuit path, in response to the closing of jog button 12, energizes solenoid 46, which in turn closes

contacts

48, 50 to activate the knitting machine drive. The release of the jog button 12 interrupts the circuit path through solenoid 46 and in turn opens

contacts

48, 50 to deactivate the knitting machine drive. There is no holding circuit for the jog button and it is therefore seen that the knitting machine will be activated only while the jog button is manually depressed. Thus, the jog button is used to turn the knitting machine for limited amounts controlled substantially by the length of time jog button 12 is manually depressed. It will be evident that since the human element is involved in the operation of the jog button, the amount of rotation by the knitting machine under the control of the job button cannot be accurately controlled. More important, however, the minimum amount of rotation of the knitting machine which can be obtained under the manually controlled jog button can normally not be sufiiciently small to serve certain desired purposes. Accordingly, while the jog button is a most useful component of the control for the knitting machine, it cannot perform some of the more delicate necessary functions, among which is that of rotating the knitting machine for a fixed finite amount of extremely small magnitude.

One-way diode 74 prevents the completion of a circuit through solenoid 54, upon closing of jog button 12. The necessity for diode 74 is clear as the energization of solenoid 54 would define a holding circuit, upon closing of the jog button, and would in fact make the jog button operate precisely in the same manner as the start button. The use of diode 74 permits the use of a single contact normally open jog pushbutton, contrary to the double contact push button conventionally used for such purpose. It will be clear from the manner in which the jog button is linked into the circuitry, that while the machine is under normal operation, in response to the depression of the start button, the accidental depression of the jog button has no effect whatsoever on such normal operation.

4 OPERATION OF THE INCH BUTTON With DC provided across

terminals

40 and 42, a completed circuit can be traced through terminal 40, terminal 52, terminal 66, terminal 68, one-way diode 82, terminal 84, terminal 86, resistor 88, resistor 90, terminal 92, terminal 94, terminal 96, terminal 98, terminal 62, normally closed stop button 16, terminal 64 and terminal 42. This completed circuit does not include solenoid 46 and the completion thereof does not have any effect, as such, on the activation of the knitting machine drive. Resistor in said circuit path, defines a voltage divider or rheostat to permit movable terminal to pick off a desired voltage drop. It will be evident that when movable terminal 100 is in contact with the bottom end of resistor 90, the voltage drop picked off thereby will be zero while when such terminal is at the highest point on resistor 90, the voltage drop "will be a maximum, such maximum being determined by the relationship between fixed resistor 88 and resistor 90. When terminal 100 does pick up a voltage, there will be a completed circuit path from terminal 100, terminal 102, resistor 104, resistor 106, resistor 108, emitter circuit of transistor amplifier '110, and terminal 96. Such current flow through the emitter circuit of transistor amplifier 110, if it is of sufficient magnitude, as determined by the pickup point of terminal 100, will trigger a correspondingly amplified current to flow from terminal 84, through resistor 112, terminal 114, solenoid 116, transistor 110, and terminal 96. Such current flow will energize solenoid 116 and cause contact 118 to open and contacts 120, 122 to close. Such closing of

contacts

120, 122 places inch button '14 in series with solenoid 46 and thus, in substantially the same condition as jog button 12. Thus, if no further circuitry were provided, pushing button 14 would have precisely the same effect as pushing jog button 12 so long as the voltage picked off by terminal 100 was sufficient to cause the closing of

contacts

120, 122.

In accordance with the invention, there is provided a device, which generates a voltage having an amplitude responsive to the rotation of the knitting machine. Such generating device could be a conventional DC generator G geared in with the drive motor, or directly to the knitting machine, or to any other element whose movement corresponds to that of the knitting machine. The output of such generator is connected across resistor 106 at

terminals

124 and 126 and the polarity of such connection is such that the voltage across resistor 106 obtained from the generator is of opposite polarity to the voltage drop across resistor 106 resulting from the current flow therethrough originating from terminal 100. Accordingly, when the knitting machine isrotated, a voltage proportional to the amount of rotation of the knitting machine is applied across resistor 106. Thus, the greater the amount of rotation of the knitting machine from its rest condition, the greater the voltage applied across resistor 106. It will be seen, therefore, that if the voltage impressed across resistor 106 is of suflicient magnitude, it can reduce current flow through said resistor sufiiciently to render transistor 110 non-conducting, at least insofar as current flow through solenoid 116 is concerned. When solenoid 116 is de-energized as the result of the interruption of current flow therethrough,

contacts

120, 122 will be opened and

contacts

118, 120 will be closed.

The operation of the inch button will now be specifically described. With movable terminal 100 set in position to permit sufficient current flow through transistor 110 to cause the energization of solenoid 116,

contacts

120, 122 will be closed. The depression of inch button 14 will now complete a circuit from terminal 68 through solenoid 46, terminal 70,

closed contacts

120, 122, closed inch button 14, terminal 98 and terminal 62. Such will energize solenoid 46 causing the closing of

contacts

48, 50 and activating the drive for the knitting machine. As the knitting machine rotates from its rest condition, the generator will generate a voltage of gradually increasing amplitude until it reaches a magnitude sufficient to block current flow through resistor 106 and transistor 110, at which time current flow through solenoid 116 will 'be interrupted deenergizing the solenoid and opening contacts 120', 122 to immediately de-energize solenoid 46 and interruptthe drive of the knitting machine. Such interruption will take place even though inch button 14 continues to be depressed. It will be evident that the larger the voltage drop across resistor 106, the larger the amount of rotation of the knitting machine from its rest condition before current is blocked through transistor 110. Since the voltage drop across resistor 106 is determined by the location of movable terminal 100, adjustment of the latter determines the amount of rotation of the knitting machine resulting from the depression of inch button 14. As terminal 100 contacts resistor 90 closer to terminal 92, the voltage picked off thereby will be smaller and the voltage drop across 106 correspondingly smaller to in turn require, only a small amount of rotation of the knitting machine before sufiicient voltage is generated to block current flow through resistor 106, and cause the interruption of the drive of the knitting machine. The significant feature of the inch button circuitry is that the amount of rotation obtained by pushing the inch button can be fixed to a finite amount of very small magnitude as it is independent of any human element. The pushing of the inch button is necessary to initiate rotation of the knitting machine but this very rotation, however, generates the voltage which causes deactivation of the drive for the knitting machine, removing the human element from the deactivation. step. It will be noted that there is provided condensor 44 which is in series with one-way diode 82 and that such series combination is across

input terminals

40 and 42. The purpose of the foregoing arrangement is to smooth out the DC between

terminals

84 and 42 as a purer DC is desirable for supply to the circuitry associated with the operation of the inch button, as above described. While the above inch button circuitry has been described in connection with a generator as being the source of the blocking voltage, it will be understood that instead of such generator, other elements could be provided so long as such could generate a voltage pulse responsive to the rotation of the machine.

When the knitting machine stops rotating under the inch button action, the operator will have obtained the desired predetermined finite rotation of the machine and would normally remove his hand from the inch button. If, nonethless, the inch button is retained in depressed condition, even though the machine will have come to rest, reducing to zero the blocking voltage generated and impressed across resistor 106, the following will occur. The absence of blocking voltage will permit triggering current to flow through transistor 110. Notwithstanding such triggering, current will not flow through solenoid 116 because the continued depression of inch button 14 defines a short circuit between

terminals

114 and 98 to prevent any current from passing through solenoid 116 and thus preventing it from being energized. This in turn will prevent the reenergization of solenoid 46 and thus the rotation of the machine. It is therefore seen that if the inch button is retained in depressed condition, it will not result in additional successive finite amounts of rotation of the knitting machine. If any additional finite amounts of rotation are desired, the inch button must be released and depressed again. 1

It will be observed from the drawing that the stop button 16 overrides all other buttons so that the depression thereof will always interrupt the drive for the knitting machine. Similarly, it will be noted that the drive control described herein is interconnected with the stop motion to the extent that the activation of the stop motion arising out of a defect in the knitting operation causes energization of stop motion power pack relay 20 which in turn opens

contacts

22, 26 to interrupt all power supply to the knitting machine drive control.

From the above it is clear that the drive control in accordance with the present invention provides simple and efficient circuitry to permit the knitting machine to be 1) started for continuous operation, (2) started for rotation by manual depression of a jog button for short periods of time determined by the length of depression of the jog button, (3) operated to rotate the knitting machine for preselected finite amounts independent of the human factor, and (4) stop at any time.

While I have herein shown and described the preferred embodiment of my invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that in the illustrated embodiment certain changes in the details of construction and in the form and arrangement of parts may be made without departing from the underlying idea or principles of this invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A control circuit for controlling the drive of a rotating machine comprising:

a first circuit path (68, 46, 70, 122, 120, 98) being operative, when energized, to activate said drive and being operative, when de-energized, to deactivate said drive;

a second circuit path (84, 112, 114, 116, 110, 96)

being operative, when energized, to energize said first circuit path and being operative, when de-energized, to de-energize said first circuit path;

means (G) responsive to the rotation of said machine and operative, in response to a predetermined amount of rotation, to de-energize said second circuit path, whereby said first circuit path is de-energized and said drive is deactivated;

said second circuit path including a transistor amplifier connected therein so that the current flowing through said second circuit path is the amplified current obtained by triggering said transistor;

and a third circuit path, one end of which is connected to the emitter of said transistor amplifier so that the current flowing through said third circuit path defines the triggering current for said transistor;

said third circuit path including a series resistor, and said means responsive to the rotation of said machine being a DC generator having its terminals connected across said resistor with such polarity that the voltage impressed by said generator across said resistor is opposite in polarity and tends to block the voltage drop across said resistor obtained from current flow through said third circuit path.

2. A control circuit in accordance with claim 1, wherein said second circuit path includes a series solenoid which is operative, when energized by current flow through said second circuit path, to close a pair of series contacts in said first circuit path and which is operative, when de-energized, to open said two contacts and thereby provide said de-energization of said first circuit path.

3. A control circuit in accordance with claim 1, wherein the amount of current flow through said third circuit path is adjustable so as to correspondingly render adjustable the voltage drop across said resistor whereby to vary the voltage required to be generated by said generator in order to block current flow in said third circuit path.

4. A control circuit in accordance with claim 1, wherein there is provided a fourth circuit path including a start pushbutton which, when closed, is operative to initiate the activation of said drive for said rotating machine, said fourth circuit path being provided with a holding circuit whereby initial activation of said drive is mantaned after said pushbutton is reopened.

5. A control circuit in accordance with claim 4, wherein there is provided a fifth circuit path including a jog button which, when closed, is operative to initiate the activation of said drive for said rotating machine and which, when reopened, is operative to deactivate said drive, whereby rotation of said machine corresponds to the time interval during which said jog button is closed.

6. A control circuit for controlling the drive of a rotating machine comprising:

a first circuit path (68, 46, 70, 122, 120, 98) being uperative, when energized, to activate said drive and being operative, when de-energized, to deactivate said drive;

a second circuit path ('84, 112, 114, 116, 110, 96) being operative, when energized, to energize said first circuit path and being operative, when de-energized, to de-energize said first circuit path;

said second circuit path including a series solenoid which is operative, when energized by current flow through said second circuit path, to close a pair of series contacts in said first circuit path and which is operative, when tie-energized, to open said two contacts and thereby provide said de-energization of said first circuit path;

and a pushbutton which is in series in said first circuit path when said pair of series contacts is closed.

' 7. A control circuit in accordance with claim 6, wherein the opening of said pair of series contacts is effective, by closing another pair of contacts, to place said pushbutton across said solenoid, whereby the closing of said pushbutton when said another pair of contacts is closed short circuits said solenoid to prevent the latter from being energized unless said pushbuttonis released.

8. A control circuit for controlling the drive of' a rotating machine comprising:

a source of DC power provided between a postive and a negative terminal;

a solenoid which is operative, when energized, to activate said drive;

a one-way diode being connected at one of its terminals to said solenoid;

a start button connected to the other terminal of said diode whereby said solenoid, said diode, and said start button are in series so that the closing of said start button defines a continuous flow of DC current through said solenoid;

a holding circuit for said start button, whereby current flow through said solenoid is maintained following depression of said start button, regardless of ensuing release thereof;

and a jog button electrically connected between the negative terminal and the junction of said solenoid and said diode, whereby the closing of said jog button provides a continuous circuit path for DC current through said solenoid and said jog button only so long as said jog button is depressed.

References Cited UNITED STATES PATENTS 2,686,895 8/ 1954 Feldhausen 318-443 2,985,808 5/ 1961 Ketchledge 318-443 2,773,231 12/1956 Adriansen 318443 JOHN F. COUCH, Primary Examiner DENNIS l. HARNISH, Assistant Examiner US. Cl. X.R.