US3668904A

US3668904A - Device for automatically regulating the thread consumption of warped knitting machines

Info

Publication number: US3668904A
Application number: US26496A
Authority: US
Inventors: Karel Murenbeeld
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-04-08
Filing date: 1970-04-08
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13

Abstract

A device for automatically regulating the thread consumption of warp knitting machines in which plural warp beams are propelled from a mainshaft by respective variable drives is provided. This device consists of electrical contact means for determining the r.p.m. of the mainshaft, together with a setting device means for fixing the desired speed of thread consumption. A control mechanism is also provided for part of the device which includes electrical impulse generator means on the respective warp beams for indicating thread consumption together with a counter means including subtracting mechanism means for measuring the difference between desired and actual values of thread consumption and having output signal means for adjusting the r.p.m. of individual warp beams through said variable drive. The device further includes switching means for adapting the control mechanism means for successively regulating the r.p.m. of plural warp beams of one or more warp knitting machines through connection with the electrical impulse generator means and the variable drives of the respective warp beams, and means for causing switching of said control mechanism means from one warp beam to another in response to signal from the electrical impulse generator on the warp beam last regulated at the time of switching.

Description

United States Patent Murenbeeld 51 June 13, 1972 [54] DEVICE FOR AUTOMATICALLY REGULATING THE THREAD ABSTRACT CONSUMPTION 0F WARP ED A device for automatically regulating the thread consumption KNITTING MACHINES of warp knitting machines in which plural warp beams are [72] inventor: Karel Murenbeeld, 20Chernin Soujet ar a m by wi f dnvesfls 1234 vcssy near Geneva Switzerland provl e is device consists of e ectnca contact means or determining the rpm. of the mamshaft, together with a. [22] Filed: April 8, 1970 setting device means for fixing the desired speed of thread I consumption. A control mechanism is also provided for part [21] 26496 of the device which includes electrical impulse generator means on the respective warp beams for indicating thread [52] US. Cl. consumption together with a counter means including ub. 4 23/00 tracting mechanism means for measuring the difference Field 0f Search /8 6 3 318/6; between desired and actual values of thread consumption and 28/35; 39/97, 108 having output signal means for adjusting the r.p.m. of individual warp beams through said variable drive. The device [56] Remnces further includes switching means for adapting the control UNITED STATES PATENTS mechanism means for successively regulating the rpm. of

plural warp beams of one or more warp knitting machines 2,674,109 4/1954 Bassist ..66/86A through connection with the electrical impulse generator 2,871,685 2/1959 Bassist means and the variable drives of the respective warp beams, ,615 2/ 1963 C0 and means for causing switching of said control mechanism 3,221,519 12/1965 Bassist means from one warp beam to another in response to signal 3,364,403 1/1968 Liebchen ..318/6 Primary Examiner-Louis K. Rimrodt Attorney-Walter G. Finch from the electrical impulse generator on the warp beam last regulated at the time of switching.

5 Claims, 3 Drawing Figures PATENTEDJUM 13 m2 SHEEI 10F 3 FIG? 4 I KHREL MURENBEELD PATENTEBJun 1 3 11112 3, 668. 904

SHEU 3111 3 T T I L19 77 1 V I 11 FR 3) \J 26 FIG. 3

kAREz. M RENBEELD N VE N TOR .1 DEVICE r011 AUTOMATICALLY REGULATING THE THREAD GONSUMPTION or WARPED KNITTING MACHINES This invention relates generally to knitting apparatus, and more particularly to a device for automatically regulating the thread feed or consumption of warp knitting machines.

Warp knitting machines are used for manufacturing knitted fabrics. Each machine usually includes'two warps, with each warp consisting of a large number of threads wound in parallel. In such machines, an eye-point needle is normally provided for each thread, and thousands of stitches are simultaneously formed in a row, lying on the needles, in knitting a fabric. 7 v v i The large number of parallel threads needed for such a procedure are wound on warp beams. A warp beam consists of one or more large spools (each spool being called a section beam), on which great lengths of thread material are uniformly wound. As the material is wound off the section beams during the knitting procedure, the diameter of the spooled thread is constantly decreasing.

in the manufacture of warp knitted fabrics on one or more warp knitting machines, it is important for the thread consumption and the thread speed during operation to be as constant as possible, and to be the same on each warp knitting machine, for irregular thread consumption leads to flaws and irregular construction of the fabric, so that a machine in which the thread consumption is not sufficiently regulated has a high scrap content in proportion to the output.

As the'thread consumption per stitch must be kept constant, the" most important manufacturing parameters'for the knitter are the so-called rack lengths needed for making a certain fabric. The rack length is defined as that thread length necessary for knitting 480 rows of stitches. Numerous special problems are encountered in practice in processing elastic threads, the use of which, in warp knitting, has considerably increased recently. Such threads are mostly processed with hard fibers on special double-warp looms. The elastic-power and expansion-properties of such threads make it considerably more difficult to observe the required tolerances, as the rack length on the beam, i.e. the spool-wound diameter of one rack length, or length necessary for knitting 480 rows of stitches, amounts onley to about '50 to 100 mm. Consequently, the threaded speed used is very low, but must still be exactly maintained, as fluctuations in the rack length of elastic fabrics have a considerable influence on the properties of the fabrics.

The object of the present invention is to increase the precision of the regulation of the thread consumption of several warp beams, to eliminate the manual supervision of present semi-automatic control systems and to reduce the overall fabric manufacturing costs by simultaneous control of several machines by one automatic control system.

According to this invention, there is provided a device for automatically regulating the thread consumption of warp knitting machines, in which a warp beam can be propelled by a variable drive, with an electrical impulse generator for determining the r.p.m. of the mainshaft, a setting device for fixing the desired speed of thread consumption, and a control mechanism with a subtracting mechanism, which forms the difference between desired and actual values, and whose output signal serves to adjust the r.p.m. of the warp beam,

. wherein the control mechanism for regulating the r.p.m. of

several warp beams of one or more warp knitting machines can be successively connected through a selector switch with the impulse generators and the drive-setting devices of the individual warp beams, and the continued switching of the selector switch can be controlled by an impulse generator driven by the main shaft associated with the wrap beam, whose r.p.m.

. has in each case been regulated.

The invention is based on the idea that it no longer necessary to connect the control mechanism continuously with the impulse generator or the drive-setting device, when the subdivision ofthe impulsegenerator is finely enough selected in order to obtain high measuring precision. in warp knitting machines, an important factor is to undertake of the withdrawal speed. Once the speed is set, the next measuring need not follow directly, but it can be reckoned that there will be a multiple deviation only after withdrawal of a great length of thread. Thus the control mechanism can be used, after termination of the regulation of the thread speed of a warp beam, in order to make corrections in other warp beams driven in a similar way, until said mechanism is again switched through to the first warp beam during the switching cycle. A control mechanism is not switched from one warp beam to the next at fixed intervals, as switching the control mechanism to a warp beam not only efiects delivery of a measurement result, but also the entire measurement procedure and the transfer of the correction signal to the warp beams precise setting drive-setting device. The selector switch is switched from the machine to which it is connected in each case only after termination of each measurement. Thus it is possible to use the length of the measurement procedure as an important parameter, influencing the measurement result. As a result of logical control of the switch-over moments by the main shaft of the warp beam according to contact at any moment, the expense of equipment previously found necessary at the measuring point with the conventional use of multiplex processes, is

5 considerably reduced. This is because the measurement result according to this invention is first determined and immediately employed in the control mechanism, the only requirement at the measurement point being that the measurement dimension be present in the form of electrical impulse signals, but not yet in prepared form. I

The thread speed to be pre-selected can be independently set for each warp beam on a separateselector index, so that the measurement procedure is fed at the start of each counting procedure, with the content of the relevant pro-selector index, while the impulses given ofi by the measurement scanners continuously reduce the counter level. The value present in the binary counter on completion of the counting is a measure of the deviation, and can serve to control a step-by-step motor, which thereupon adjusts the transmission ratio of the adjustable drive.

Embodiments of the invention will now way of example, with reference drawings, in which:

FIG. 1 shows diagrammatically a control system according to the invention, built into a warp knitting machine with two warp beams;

FIG. 2 shows diagrammatically a switching-type system of control for several independent machines; and

FIG. 3 shows diagrammatically a control system in which the delays between the individual measuring procedures are reduced.

In FIG. 1 two warp means, 1 and 2 are shown in diagrammatic side view with their respective shafts 3, 4 driven by infinitely variable regulating

gearings

5, 6. Warp beams l, 2 consist of a large number of threads wound in parallel, the processing speed of which is kept constant by the respective regulating

gearings

5, 6.

On the input side, the regulating gearings are driven by the main shaft of the machine which is shown diagrammatically at 11.

The delivery speed of thread unwound from the warp beams l, 2 are measured by respective friction wheel assemblies 9, 10 which are freely rotatable, and which are pressed against the warp beams by springs (not shown). The friction wheel assemblies 9, 10 include photoelectric impulse generators, and, on rotation, generate electrical impulse-signals of a predeterbe described, by to the accompanying mined amplitude. As the impulse generator parts of the assemfriction wheel and impulse generator of 1:5, on condition that the generator emits 250 primary impulses per revolution with a friction wheel of 80mm diameter, one impulse is emitted per 0.05mm of thread withdrawn. At a rack length of about 50mm, which can be usual for elastomeric warp beams on elastic double-warp looms, a-measurement precision of 0.01 percent results if an entire rack length is measured, and correspondingly, a precision of 0.02 percent results when measurements are taken over half a rack length. This latter case corresponds to 240 revolutions of main shaft 11.

. A pre-selector index l3, 14 is respectively associated with each warp beam 1, 2. The measuring device common to the warp beams consists of a forward-and reverse-counting binary counter 16, which can be connected through a program switch to the devices of each warp beam. Switch 12 switches contacts A, B, C and D of program switch 15 alternately with contacts A 8,, C,, D,, of warp beam 1 and the contacts A B C, D of warp beam 2. In the switching position shown by the extendedline 12 the binary impulses corresponding to the speed of warp beam 1 from impulse generator 9 to switch contact A, are equated, and pass through the program switch 15 to binary counter 16.

The main shaft 11 of the knitting machine further activates a switch 18' which emits an impulse for every rack (480 revolutions) or for every half-rack. This switch can also be activated by a sprocket, or by a two lobe cam. it controls the startand end of each measuring procedure. The measuring device, comprising counter 16 and component 17 to be described later, is likewise switched over from one warp beam to the other by switch 18, if necessary with a delay, through circuit 19.

At the start of the measurement, the numerical value (controlled by main shaft contact switch 18) which is present in the pre-selector index 13, is stored in the impulse counter 16. Counter 16 next counts the impulses of the impulse generator 9 in reverse. If only zeros appear in the impulse counter at the end of the measurement, which is determined by the next impulse of the main shaft contact switch 18, then the actual speed of the threads for processing corresponds to the pre-set desired value in pre-selector.index l3, and it is not necessary to make any additional adjustment by means of the step-bystep motor 7. If there is still a numerical value in the impulse counter 16 at the end of the measurement, this is passed, with the correct sign (positive/negative) to control device 17, which transforms it into a corresponding number of single impulses, and effects switching-forward of the step-by-step motor 7-via contacts C C Contacts D, D and D, serve to feed the determined deviations from the actual value to a multi-channel printer 20, so that it is possible at any time to check themethod of operation by means of the automatic record. Y

Counter 16, is preferably an electronic forward-and-reverse counter, and is in position to add positive impulses and substract negative ones from them. Thus the effects of vibrations in the machine which could otherwise cause the impulse generator 9, on oscillation, for example, to emit several impulses although no thread has been wound off, are nullified.

If the machine is set in motion, the desired values for the thread speed must be manually pre-set on the pre-selector indexes l3, 14. When main shaft 1 1 begins to rotate the first impulse of the main shaft switch 18 switches on counter 16. At the same time the counter level of the pre-selector index 13 is taken into counter 16, so that the level on counter 16 is reduced by each impulse arriving from the measurement scanner, the friction wheel impulse generator assembly 9. When the next impulse from main shaft switch 18 arrives, the counting procedure of counter 16 is terminated, and the counter level still present in this counter is fed into the control device 7, which transforms it into a corresponding number of single impulses, and passes them'to the step-by-step motor 7 via contacts C C When the counting procedure is terminated, counter 16 additionally generates a delayed impulse, which, through circuit 19, causes the program switch to switch over to the next warp beam.

The control system shown in FIG. 1 illustrates a system for equipping both warp beams of one warp knitting machine with a common measuring device. FIG. 2 shows a further feature of this invention, the commotion of a control system for two warp beams each of two knitting machines. It should be assumed here that the control system shown on the left in FIG. 2 substantially corresponds to the device shown in FIG. 1, identical parts being provided with the same reference numbers. In the device shown on the right in FIG. 2, only the additional elements involved in controlling two warp beams each of two knitting machines are drawn. The essential difference between FIG. 1 and FIG. 2 lies in the fact that two

independent shafts

11, 21, are present in the coupling of two machines, two main shaft switches 18, 22 therefore ,being necessary. In the condition illustrated in FIG. 2, it is necessary, in switching from one machine to the other, to throw both

switches

18 and 22 of the main shafts, as then no other sychronization is necessary between the machines. In order to make the switch-over possible, contacts E and E are supplied on the first machine, and corresponding contacts E and E, are supplied on the second machine. Using a single

main shaft switch

11, 21, the delay afier switch-over, and until the next measurement, corresponds to a maximum 480 revolutions or one rack. Thus, substantial time losses might occur between each measurement. In order to shorten these and to increase the capacity of the control device,

impulse generators

25, 26, as in FIG. 3, can be mounted on main shafts ll, 21 instead of the main-

shaft switch contacts

18, 22. The

impulse generators

25, 26, generate ten impulses per revolution of the main shaft. When it is necessary to measure the thread speed over a measuring time of one rack, corresponding to 480 revolutions of the main shaft in a typical case, the impulses of the

second impulse generator

25, 26 must be counted. This is required for termination of the counting procedure of main counter 16 after the number of impulses corresponding to 480 revolutions of the main shaft. In the example shown in FIG. 3, an additional index 27 is provided in which the desired number of impulses of the main-shaft impulse generator 25 can be stored. This value is continuously compared with the counter level of the secondary counter 28 which 'is connected with the program switch 15 and the binary counter 16, and when the control result agrees with the pre-set value, the measurement is interrupted in order to connect the program switch to the succeeding machine which it is to control. The succeeding machine is likewise equipped with an impulse generator 26 on main shaft 21, and the dead time occurring between the two measurements corresponds, at the selected dimensions of the main-shaft impulse generator 25," 26, to a maximum of a tenth of the time necessary for a main-shaft revolution.

In summary, the teachings of this invention provide means by which a single control or measuring device can be used to supervise a large number of knitting machines while preserving the required degree of precision.

The invention is not restricted to the example shown. According to this invention, it is possible, for example, to construct a warp knitting machine without mechanical beamregulating gearings in which the propulsion of the beam is effected directly by means of a regulable electric motor controlled by a digital analogue converter which converts the signals of the counter into a continuous control flow.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A device for automatically regulating the thread consumption of warp knitting machines in which plural warp beams are propelled from a mainshaft by respective variable drives, comprising: electrical contact means for detennining the rpm. of the mainshaft, setting device means for fixing the desired speed of thread consumption; control mechanism means, including electrical impulse generator means on the respective warp beams for indicating thread consumption; and counter means including subtracting mechanism means for measuring the difference between desired and actual values of thread consumption and having output signal means for adjusting the r.p.m. of individual warp beams through said variable drive; switching means for adapting the control mechanism means for successively regulating the rpm. of plural warp beams-of one or more warp knitting machines through connection with the electrical impulse generator means and the variable drives of the respective warp beams, and means for causing switching of said control mechanism means from one warp beam to another in response to signal from the electrical impulse generator on the warp beam last regulated at the time of switching.

2. A device according to claim 1 wherein the variable drives individually comprise variable gearing adapted for actuation by a step-by-step motor and have a step-by-step motor for actuating .the variable gearing, and wherein the control mechanism counter means comprises a pre-settable binary reverse counter means for controlling said variable drives in accordance with the counting level therein on termination of a 6 said measurement by the control mechanism means.

3. A device according to claim 2 wherein the plural warp beams are in plural knitting machines, wherein in order to supervise the operative duration of each warp beam the mainshafts of the warp knitting machines are individually equipped with impulse generators successively connectable with said control mechanism means, and wherein said control mechanism means includes an auxiliary counter responsive to said impulse generators for emitting an evaluation signal to the pre-settable binary reverse counter means at a predetermined auxiliary counter count level, thereby switching the control mechanism from one warp beam to the next.

4. A device according to claim 1, wherein the electrical impulse generator means is of the type which operates independently of the direction of actuating movement thereof, and wherein the counter means is of the forward-reverse binary counter type.

5. A device according to claim 1 wherein the electrical contact means for determining the r.p.m. of the mainshaft comprises an electrical impulse generator connected with said mainshaft.

i I l i

Claims

1. A device for automatically regulating the thread consumption of warp knitting machines in which plural warp beams are propelled from a mainshaft by respective variable drives, comprising: electrical contact means for determining the r.p.m. of the mainshaft, setting device means for fixing the desired speed of thread consumption; control mechanism means, including electrical impulse generator means on the respective warp beams for indicating thread consumption; and counter means including subtracting mechanism means for measuring the difference between desired and actual values of thread consumption and having output signal means for adjusting the r.p.m. of individual warp beams through said variable drive; switching means for adapting the control mechanism means for successively regulating the r.p.m. of plural warp beams of one or more warp knitting machines through connection with the electrical impulse generator means and the variable drives of the respective warp beams, and means for causing switching of said control mechanism means from one warp beam to another in response to signal from the electrical impulse generator on the warp beam last regulated at the time of switching.

2. A device according to claim 1 wherein the variable drives individually comprise variable gearing adapted for actuation by a step-by-step motor and have a step-by-step motor for actuating the variable gearing, and wherein the control mechanism counter means comprises a pre-settable binary reverse counter means for controlling said variable drives in aCcordance with the counting level therein on termination of a said measurement by the control mechanism means.