US3216081A - Cloth feed apparatus for tenter frames and the like - Google Patents

Description

Nov. 9, 1965 A. LEIMER ETAL 3,216,081

CLOTH FEED APPARATUS FOR TENTER FRAMES AND THE LIKE Filed Feb. 21, 1962 5 Sheets-Sheet 1 INVENTORJ ALE/fi musk Lam/a LEAL NOV. 9, 1965 LE|MER ETAL 3,216,081

CLOTH FEED APPARATUS FOR TENTER FRAMES AND THE LIKE Filed Feb. 21, 1962 5 Sheets-Sheet 2 IN V EN TORS inn/M 44.46

4 I'm/CHEFS Nov. 9, 1965 A. LEIMER ETAL 3,216,081

CLOTH FEED APPARATUS FOR TENTER FRAMES AND THE LIKE Filed Feb. 21, 1962 3 SheetsSheet 5 H II W461 iil III @52 2 MON/6 87.6- BY MMM United States Patent 3,216,081 CLOTH FEED APPARATUS FOR TENTER FRAMES AND THE LIKE Albert Leimer, Beimlerstrasse 15, Augsburg, Germany,

and Ludwig Zerle, Lietershofen, near Augsburg, Germany; said Zerle assiguor to said Leimer Filed Feb. 21, 1962, Ser. No. 174,726

Claims priority, application Germany, Feb. 22, 1961,

E 20,644 2 Claims. (Cl. 26-57) This invention concerns an improved arrangement for effecting lateral movement of the lead-in cheeks of a textile tentering frame at continuously variable speeds.

At the entrance to cloth tentering frames in the textile industry it is necessary to position the lead-in cheeks of the chains thereof as accurately as possible relative to the selvedges of the cloth. The chains lie along the lead-in cheeks, and bear either needles or clamps to which the cloth run must be fastened by its outer selvedges. With needle chains the fastening is effected by pressing the edges of the cloth onto the needles of the chains, and with clamp chains, the edges of the cloth are gripped by expanding clamps carried on the chains.

A great number of proposals have been made to solve the problem of positioning the lead in cheeks at the selvedges of the cloth. Some of these prior proposals involve adjustment devices operating in such manner that the speed of movement of the lead-in cheeks is constant. Such devices work in a jerky fashion, which naturally (especially when the speed of movement of the lead-in cheeks must be high) is undesirable. In an elfort to avoid such jerky operation, other embodiment have been developed which use a variable speed of movement. However, even here, such structures have had undesirable characteristics, particularly in respect to the fact that the maximum adjustment speed of the lead-in cheeks, with arrangements of these general types suggested heretofore, has ordinarily been too low to permit efficient use of the adjustment apparatus with modern high efliciency tenter frames; particularly with cloth selvedges which deviate to a large extent when some inadequacy in the lead-in apparatus does not allow secure grip of the cloth selvedges.

If the disadvantages of lead-in position adjusting apparatuses presently employed are analyzed, one finds Without exception that they are characterized by relatively low speeds. Moreover, the apparatuses are generally such that a significant increase in adjustment speed has been unrealizable in practice for two reasons, namely:

(1) When the apparatus comprises a fixed speed adjustment system, efforts to speed up the adjustment operation aggravate the sudden and jerky adjustment motions described above.

(2) When the apparatus is such that it effects adjustments at variable speeds, the adjustment apparatus is generally characterized by large masses which have to be accelerated and braked, whereby efforts to speed up the adjustment operation often cause the entire system to oscillate at high adjustment speeds.

In overcoming the foregoing disadvantages of systems utilized heretofore, the present invention employs not only the size of the deviation to adjust the lead-in cheeks, i.e., small deviations effect a low speed of adjustment while large deviations elfect a high speed of adjustment, but also employs the speed of deviation to control the adjustment.

This means that the signal for the distance deviation has superimposed on it an impulse signal which represents a measurement for the deviation speed. Both signals are effective in the same direction.

The procedure holds good both for acceleration and delay of the adjustment. Should the acceleration and de- 3,21 6,08 1 Patented Nov. 9, 1 965 lay process be translated into a mathematical expression then the power influencing the adjustment device is dependent on the deviation travel and the differential quotients of the deviation travel with respect to time.

The efficiency of this arrangement is especially clear if the delay or brake process is considered. Should the cloth selvedge wander away, and the lead-in cheek run after it at a high speed, then the adjustment appliance receives, before zero is attained, not only the signal for the lower adjustment speed corresponding to the approach to zero but also receives a further impulse effective in the same direction thereby to strengthen the braking effect.

The additional braking impulse can even be made so large that the adjustment appliance receives the signal for a reverse movement even before zero is reached. By this means, exceptionally etficient braking can be attained.

The deviation is detected by an appropriate feeler, as will be described; and the feeler employed in the present invention must be adapted to give .a signal which varies continuously in relation to displacement of the cloth selvedge. Examples of this are a variable resistance, a potentiometer, an arrangement of photo cells, an induction coil or the like.

An overall arrangement constructed according to the present invention thus comprises an apparatus for feeding cloth runs into tenter frames of the kind having leadin cheeks adapted for movement to follow deviations of the selvedges of the cloth run in response to control means operated by at least one sensing device associated with one of said selvedges, characterised in that said control means give an output which effects said movement and which is dependent upon both the magnitude of said deviations and upon the rate of change of said deviations.

The invention will now be described further with reference to the accompanying drawings which show, by way of example only, one embodiment of the invention and of which:

FIG. 1 shows the mechanical construction of the feedin apparatus for a lead-in cheek;

FIG. 2 shows the electrical circuit associated with the feed-in apparatus; and

FIGS. 3a to 30 show diagrammatically the electrical procedure when the cloth run wanders away.

Referring now to FIG. 1 a feeler lever 1 Which lies on a selvedge of the cloth run 2 is connected by an axle 3 to the control 4 of a potentiometer 5. A spring 6 is fixed at one end to an extention 7 of the feeler lever 1 and at the other end to a rod 8 and serves to press the feeler lever continuously and lightly against the selvedge of the cloth. The entire feeler device is firmly connected to the lead-in cheek 11 of the tenter by a bolt 9 and a bearing arm 10. The lead-in check 11 is supported on a bearer 13 by a roller 12. The terminals of the potentiometer 5 are electrically connected by wires to a control appliance 14. The control appliance 14 feeds the field windings of a DC. generator 15.

A three phase motor 16 is coupled with the DC. generator 15 and serves to drive said generator. The DC. generator 15 feeds the armature winding of a DC motor 17 associated with the adjusting appliance.

The DC. motor 17, the DC. generator 15 and the three phase motor 16 are connected to form a Ward- Leonard set. The DC. motor 17 drives a pinion 19 through a gear box 18. The DC. motor 17 and gear box 18 are secured on a swivel arm 20 which is pivotally mounted on a bolt 21, which is secured to the lead-in cheek 11.

The pinion 19 engages a rack 22 which is securely fastened to the bearer 13.

A spring is stretched between a holding bolt 24 and the arm 20 which presses the pinion 19 continuously into engagement with the rack 22. The arrangement described forms the adjustment device of the feed-in apparatus. When the motor 17 rotates pinion 19, the lead-in cheek 11 moves in one direction or the other.

Referring now to FIG. 2 the potentiometer is again illustrated as being operated by the aforementioned feeler lever 1, and its terminals 26 and 27 are connected to a positive feed-line 28 and a negative feed-line 29, respectively. The voltage tapped between positive feed-line 28 and negative feed-line 29 by the control 4 of the potentiometer 5 is supplied to control appliance 14 comprising, in part, a voltage divider comprising resistances 30 and 31. Control appliance 14 further includes transistors 32 and 36 interconnected to one another, and to the voltage divider 3031 in the manner illustrated in FIGURE 2. The voltage across the resistance 31 is supplied across the base and emitter of transistor 32. The field winding 33 of the D.C. generator 15 is supplied from the collector 25 or transistor 32.

The base 35 of transistor 36 is connected to the collector 25 of transistor 32 through a resistance 37. The field coil 34 used for the other direction of rotation, of the D.C. generator 15, is supplied from the collector of transistor 36.

Since the current through the transistor 32 is controlled by the voltage on resistance 31, the current through transistor 36 is bound to be influenced thereby. At a given voltage across resistance 31 the currents through transistors 32 and 36 are of equal magnitude, and the fields produced by the windings 33 and 34 of the D.C. generator 15 accordingly cancel out. As a result, no voltage appears across armature terminals 38 and 39 of the generator 15. It should be noted that the inclusion of resistor 37 in no way prevents the currents through transistors 32 and 36 from being of equal magnitude. The current through transistor 32, for example, may flow along the path between lines 28 and 29, comprising the emitter and collector circuits of transistor 32, and generator field coil 33. The magnitude of the current flowing in this path is dependent upon the signal applied to the base of transistor 32; and since transistor 32 is an amplification device, the signal applied to its base is of smaller magnitude than the current flowing through its emitter and collector circuits. Analogous operation occurs in respect to transistor 36, in that the current flowing through the emitter and collector circuits of transistor 36 (and through generator field coil 34 in series therewith) will be greater than the signal applied to the base 35 of transistor 36. The resistor 37 connected to the collector of transistor 32 operates to tap a small portion of the collector current appearing at point 25, thereby to provide a signal at base 35; and while the signal so applied to base 35 is smaller in magnitude than the current at collector 25, the amplification of transistor 36 can raise the current flowing through the collector circuit of transistor 36 to a value equal to that flowing in the collector circuit of transistor 32. It is clear, therefore, that the inclusion of resistor 37 in no way prevents the emitter currents of the transistors 32 and 36 from equalling one another.

The voltage across the resistance 31, of course, acts as an input signal to transistor 32; and changes in the voltage across resistance 31 eflect related changes in the current flowing through transistor 32. These changes in current flow produce similarly related changes in the potential drop across the transistor 32, whereby the potential at point 25 (i.e., at the collector of transistor 32) will fluctuate with changes in voltage across resistance 31. These variations in potential at point 25 coupled across resistor 37 produce a change in signal input to transistor 36 thereby to vary the current in the collector circuit of transistor 36. Should the voltage increase across resistance 31, then the current through transistor 32 increases whilst that through transistor 36 decreases. The

field produced by the winding 33 accordingly predominates, and a voltage is produced across the armature terminals 38 and 39 of the D.C. generator 15. Should the voltage on resistance 31 decrease, however, then the current in transistor 32 falls below that in transistor 36, and a voltage again appears across the armature terminals 38 and 39 of the D.C. generator 15, but of opposite polarity.

The armature terminals 38 and 39 of the D.C. generator 15 are connected to armature terminals 40 and 41 of the D.C. motor 17. The exciter coils 43 and 44 of the D.C. motor 17 are wired in series between the feed lines 28 and 29. The D.C. generator 15 is driven at a constant speed by the three phase motor 16.

The D.C. motor 17 is adapted to move the support of the feeler system, generally shown at 46, to and fro in the direction of arrow 47 by the mechanical means described in reference to FIGURE 1 (not shown in FIG. 2). When the position of the cloth selvedge 48 changes, the D.C. motor 17 moves in such a way that the feeler lever 1 returns to its original position in relation to the cloth selvedge. A condensor 49 in parallel with resistance 30, cooperates with resistance 31 to differentiate voltage variations occurring between the control 4 of potentiometer 5 and positive feed-line 28. Thus any sudden voltage variation does not manifest itself across the voltage divider consisting of resistance 30 and resistance 31 to the base of transistor 32, but appears directly as an impulse of full magnitude across condensor 49, applied to the base terminal of transistor 32. The voltage impulse from condenser 49 decays in accordance with the time constant of the circuit containing condenser 49 and resistances 30 and 31.

FIG. 3a shows the behavior of the control when the selvedge of the cloth deviates in position. The feeler lever 1 lies on the selvedge 48 of the cloth run 2. The arrow 52 indicates the relative movement of feeler lever 1 in the longitudinal direction of the cloth run 2. The adjustment appliance moves the feeler in the direction of arrows 54 and 65 at right angles to the cloth run.

FIG. 3b shows variation of the voltage across resistance 31 in FIG. 2 without the condensor 49.

FIG. 30 shows the control voltage for transistor 32, that is the voltage across resistance 31 (FIG. 2) when the condensor 49 is present. At point 55 in FIG. 3b the feeler lever 1 starts to move from its zero position and causes the D.C. motor to move it in the direction of arrow 54 following the selvedge 48 of the cloth. When point 56 is reached, the speed of deviation of the selvedge 48 of the cloth and the speed of adjustment with which feeler lever 1 is moved vertically to the cloth run counterbalance one another. From point 56, as can be seen in FIG. 3b the feeler lever 1 follows at a constant speed the selvedge 48 of the cloth.

When point 57 is reached the same process is repeated but in the opposite direction. A similar voltage behavior takes place if the selvedge of the cloth deviates in the opposite direction, as is illustrated for example from point 58.

A voltage level according to point 59 in FIG. 3b corresponds to the zero position of the entire system in which no adjustment takes place.

A lowering of the voltage produces a movement in the direction of the arrow 54, in FIG. 3a. A raising of the .voltage causes an adjustment movement in the direction of arrow 65.

FIG. 30 shows once again the voltage on resistance 31 in FIG. 2 and illustrates the effect of condensor 49 in FIG. 2. When the movement of the feeler lever 1 starts at point 55, the voltage change in resistance 31 is considerably more pronounced than that illustrated in FIG. 3b.

In this manner a much quicker start of the adjustment motor 17 is obtained and the time taken to reach the necessary speed of adjustment can be lessened by the amount 61.

The behavior at point 62 according to FIG. 30 shows that the control voltage when point 62 is reached not only as in FIG. 3b slowly decreases and goes to its zero value, but for a short time even sinks below the zero value and thereby controls the opposite rotational direction. Obviously the time constant of the circuit containing condensor 49 and resistances 30 and 31 must be such that the impulse 63 in FIG. 30 has faded out at the exact moment the adjustment motor 17 comes to a standstill. Thus the size of condensor 49 should be so chosen that the system adjusts itself to the new circumstances when disturbances occur.

It will be appreciated that instead of transistors, other amplification elements such as valves or magnetic amplifiers and the like may be used.

We claim:

1. In an apparatus for feeding cloth runs into tenter frames of the kind having movable lead-in cheeks adapted to follows deviations in position of the selvedges of a cloth run in response to control means operated by at least one sensing device associated with one of said selvedges, the improvement which comprises control means including a Ward-Leonard set having an electrical generator, said generator having first and second field windings, means for variably energizing said field windings comprising first and second electrical amplifying devices coupled to said first and second windings respectively, circuit means interconnecting said first and second amplifying devices for selectively varying the outputs of said first and second amplifying devices in inverse relative relation to one another with changes in the output of said first amplifying device thereby to variably control the output of said generator, means for controlling the output of said first amplifying device comprising a resistive network having a variable resistance element connected to be varied in magnitude with deviations in position of said selvedge as detected by said sensing device, said last-named means further ineluding capacitive means coupling said variable resistance element to said first amplifying device thereby to control the output of said first amplifying device in relation to the rate of change of deviations in position of said selvedge, whereby said generator ouput comprises a voltage varying in relation to both the magnitude and rate of change of deviations in position of said selvedge, means coupling said generator voltage output to an electric motor comprising a portion of said Ward-Leonard set thereby to effect rotation of said motor in a direction dependent upon the polarity of said generator output voltage and at a speed dependent upon the magnitude of said generating output voltage, and means responsive to rotation of said motor for controlling the movement of both said lead-in cheeks and of said sensing device.

2. The apparatus of claim 1 wherein each of said amplifying devices comprises a transistor.

References Cited by the Examiner UNITED STATES PATENTS 2,496,391 2/50 Hall 31828 XR 2,636,692 4/53 Picking 226-19 X 2,961,548 11/60 Prell 226-20 X 2,974,266 3/61 Schobbe 318158 3,019,379 1/62 Zarleng 318-158 FOREIGN PATENTS 1,019,391 10/52 France.

845,635 8/52 Germany.

493,411 10/ 38 Great Britain.

OTHER REFERENCES Laur et al.: Servomechanism Fundamentals, McGraw- Hill, N.Y., 1947, pp. 151-154.

DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner.

Claims (1)

1. IN AN APPARATUS FOR FEEDING CLOTH RUNS INTO TENTER FRAMES OF THE KIND HAVING MOVABLE LEAD-IN CHEEKS ADAPTED TO FOLLOWS DEVIATIONS IN POSITION OF THE SELVEDGES OF A CLOTH RUN IN RESPONSE TO CONTROL MEANS OPERATED BY AT LEAST ONE SENSING DEVICE ASSOCIATED WITH ONE OF SAID SELVEDGES, THE IMPROVEMENT WHICH COMPRISES CONTROL MEANS INCLUDING A WARD-LEONARD SET HAVING AN ELECTRICAL GENERATOR, SAID GENERATOR HAVING FIRST AND SECOND FIELD WINDINGS, MEANS FOR VARIABLY ENERGIZING SAID FIELD WINDINGS COMPRISING FIRST AND SECOND ELECTRICAL AMPLIFYING DEVICES COUPLED TO SAID FIRST AND SECOND WINDINGS RESPECTIVELY, CIRCUIT MEANS INTERCONNECTING SAID FIRST AND SECOND AMPLIFYING DEVICES FOR SELECTIVELY VARYING THE OUTPUTS OF SAID FIRST AND SECOND AMPLIFYING DEVICES IN INVERSE RELATIVE RELATION TO ONE ANOTHER WITH CHANGES IN THE OUTPUT OF SAID FIRST AMPLIFYING DEVICE THEREBY TO VARIABLY CONTROL THE OUTPUT OF SAID GENERATOR, MEANS FOR CONTROLLING THE OUTPUT OF SAID FIRST AMPLIFYING DEVICE COMPRISING A RESISTIVE NETWORK HAVING A VARIABLE RESISTANCE ELEMENT CONNECTED TO BE VARIED IN MAGNITUDE WITH DEVIATIONS IN POSITION OF SAID SELVEDGE AS DETECTED SAID SENSING DEVICE, SAID LAST-NAMED MEANS FURTHER INCLUDING CAPACITIVE MEANS COUPLING SAID VARIABLE RESISTANCE ELEMENT TO SAID FIRST AMPLIFYING DEVICE THEREBY TO CONTROL THE OUTPUT OF SAID FIRST AMPLIFYING DEVICE IN RELATION TO THE RATE OF CHANGE OF DEVIATIONS IN POSITION OF SAID SELVEDGE, WHEREBY SAID GENERATOR OUTPUT COMPRISES A VOLTAGE VARYING IN RELATION TO BOTH THE MAGNITUDE AND RATE OF CHANGE OF DEVIATIONS IN POSITION OF SAID SELVEDGE, MEANS COUPLING SAID GENERATOR VOLTAGE OUTPUT TO AN ELECTRIC MOTOR COMPRISING A PORTION OF SAID WARD-LEONARD SET THEREBY TO EFFECT ROTATION OF SAID MOTOR IN A DIRECTION DEPENDENT UPON THE POLARITY OF SAID GENERATOR OUTPUT VOLTAGE AND AT A SPEED DEPENDENT UPON THE MAGNITUDE OF SAID GENERATING OUTPUT VOLTAGE, AND MEANS RESPONSIVE TO ROTATION OF SAID MOTOR FOR CONTROLLING THE MOVEMENT OF BOTH SAID LEAD-IN CHEEKS AND OF SAID SENSING DEVICE.

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