US2242889A

US2242889A - Means for indicating defects in thread

Info

Publication number: US2242889A
Application number: US199119A
Authority: US
Inventors: Earl A Keeler
Original assignee: Brown Instr Co
Current assignee: Brown Instruments Co
Priority date: 1938-03-31
Filing date: 1938-03-31
Publication date: 1941-05-20
Anticipated expiration: 1958-05-20

Description

E. A. KEELER May 20, 1941.

MEANS FOR INDICATING DEFECTS IN THREAD Filed March 31, 1938 2 Sheets-Sheet 2 l a/ues No/ofi- Genera/01' Se) FIG. 5.

INVENTOR. EARL A. KEELER ATTORNEY.

Patented May 20,

* UNITED STATES PATENT OFFI MEANS FOR INDICATING DEFECTS IN THREAD I Earl A. Keeler, Norristown, Pa., assignor to The Brown Instrument Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 31, 1938, Serial No. 199,119

6 Claims.

This invention relates to the detection of defective filaments in a thread and more particularly to'improved apparatus therefor.

A general object of the invention is to provide simple, reliable, and efiicient means for registering the presence of defective filaments in a thread.

A specific object of the invention is to provide improved apparatus for detecting and registering the presence of defective filaments in a thread comprising a delicate switch mechanism adapted to be actuated when engaged by defective filaments and a relay mechanism associated therewith adapted to quickly effect a recording operation responsively to such actuation of the switch mechanism. r

A further specific object ofthe invention is to provide apparatus of the character above described in which the relay mechanism referred to is capable of quickly resetting itself so as to be ',in operative condition in a minimum of time for recording the next engagement of defective filamentswith the switch mechanism after just having e flected such a recording operation.

A still further specific object of the invention is to provide simple and efiicient means for detecting the presence of defective filaments in a plurality of threads simultaneously together with means actuated thereby for recording the imperfections in all thethreads on a single recording means, and for visibly indicating the imperfections in the threads by means individual to each of the threads.

In the manufacture of fabrics from rayon or other threads, the presence of defective filaments in the individual threads shows up in the finished material in the form of fuzzy ends- Heretofore, in order to eliminate these fuzzy ends, provisions have been made for the inspection by observation of'aportion of the thread during transfer of the thread from spool to spool and rejection of any spools having an excessive number of defective filaments This inspection operation is obviously expensive, and, more important from the standpoint of producing quality material, is in-;

selves are extremely fine and small in diameter,

are made up from 40 to or more of such filaments. In accordance with a preferred embodiment of my present invention, I provide means for such automatic detection including a delicate switch member arranged in the path of the thread and an associated sensitive trigger device under control of said switch mechanism. When defective filaments engage the delicate switch mechanism, which has little inertia, a contact is closed through which only a current of minute magnitude flows, but which is effective to operate the trigger devicereferred to and thereby control the passage of a relatively'larger current.

A novel solenoid and plunger arrangement connected in circuit with the trigger device is actuated when the latter is energized and operates to record the thread imperfection on a recorder chart and simultaneously operates to deenergize the trigger device. This, in effect, permits the duration of engagement between the delicate switch mechanism and the defective filament to be extremely short and yet a record of the thread imperfection will be had. Simultaneously with the recording operation, the instrument is restored to its original condition and is immedi ately effective to record the next thread imperfection that engages the detector mechanism.

The various features-of novelty which characterize my invention. are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objectsattained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment ,of theinvention.

Of the drawings:

Fig. l is a more or less diagrammatical view illustrating one form of the invention;

Figs. 2 and 3 illustrate in detail a preferred form of detector switch mechanism which may be Fig. is a wiring diagram showing the circuit connections of a portion of the arrangement of Fig. 4.

As illustrated, more or less diagrammatically in Fig. 1, provision is made for arranging. a detector i in the path of a moving thread 2 for detecting defective filaments in the latter. For clarity and definiteness of illustration I have shown my invention as adapted for use with a winding machine in which the thread is unwound from a cop 3 and rewound on a cone 3a, the latter being mounted for rotation and driven at a desirably high speed by means not'shown. As the thread 2 unwinds from the cop 3 it passes through suitably spaced guide members 4 to a tension adjusting device 5 which may be of any suitable type known to those skilled in the art. After passing through the device 5, the thread passes over guide rolls 6 and through a guide carried on the end'of a winding arm 7. Winding arm I is in cooperative relation with the cone 3a and is continuously moved back and forth along the length of the latter by means not shown so that the thread 2 is wound on the cone 3a with a criss cross or helical wind. The thread guides 4 and the tension adjusting device 5 are mounted on a suitable bracket 8, which may in reality.

comprise part of the Winding machine itself, and the cop 3 is shown as supported by the base member of the bracket.

The detector unit I, which will be described more in detail hereinafter in connection with Figs. 2 and 3, includes a contacting arm 9 havthe position of Fig. 1 out of engagement with contact l3 due to the action of a pair of fixed flexible fingers l5 and I6, carried by stationary members Ma and Nb also mounted on the member B. Fingers I 5 and I6 engage arm 9 on either side so that as defective filaments strike the stirrup l2 and rotate arm 9 into engagement with the flexible contact l3, the flexible finger l5 sets up a resisting force which tends to restore arm 9 to its normal position when the defective filaments have passed on. Oscillation of arm 9 is dampened out as a result of the combined action of fiexible fingers l5 and I6 for, if arm 9 tends to move past its normal position on being returned thereto by finger l5, finger l6 exerts a restraining force on the arm and reduces [the extent of such movement whereby arm 9 quickly ing one end disposed in the path of the thread and pivoted intermediate its ends for rotation on a light suspension cord l9 which may be of silk or any other suitable material. As best seen in Figs. 2 and 3, cord I0 is suspended between'opposite arms of a U-s'haped member ll. arm 9 is provided at its right hand end with a bifurcated portion or stirrup 12 which may desirably be formed by providing and bending a portion of the arm 9 itself into such shape. Stirrup I2 is so arranged with respect to the thread that a respective arm is disposed on either side of the thread. The arms of the stirrup are separated by a distance slightlygreater than the ormal diameter of rthe thread so as to permit leeway for thread whipping, or in other words jerky transverse movement of the thread, but are desirably close enough to the sides of the thread so that any defective filaments on the latter will engage one or the otheror both arms.

As illustrated inFigs. 2 and 3, the detector unit I is contained in a case A, which may be of metal or other suitable material,- and is mounted in any convenient manner on bracket 8 or any other convenient part of the winding machine. A base B which may be of Bakelite or other insulating material, is fixedly secured to the inside of the case and is provided for mount- Contact ing the U-shaped member II and the other parts comes to rest in its normal position.-

Thread 2 is guided into the stirrup l2 by guide members I1 and I8 rigidly secured to the case A by screws, as shown, and-having saddle portions at their upper ends for guiding the thread. In order to facilitate the adjustment of the saddle portions relatively to the stirrup 12, the guide members are preferably provided .with slots through which the screws holding the guide members to the case A pass so that by loosening the screws the guide members may be adjusted to the desired position and then rigidly secured in that position by tightening the screws. The saddle portions of guide members l1. and I8 have a suitably rounded edge, as shown, for guiding the thread whereby the latter is normally maintained exactly between the arms of stirrup I2 when the'gui'de members have been suitably adjusted. Because of the constant sliding of the thread on the guideimembe'rs, it is noted, the saddle portions will be quickly worn away and rendered ineffective for maintaining the thread intermediate the arms of stirrup I2 unless the saddle portions are suitably hard and wear resisting. Guide members I! and I8 may'be composed of various substances which are suitably 'wear resisting such, for'example, as solid porceprefer to-employ guide members I! and I8 composed of nitralloy with a nitrided case. I

It is noted the resiliency of contact I3 permits movement of contactingarm 9 to any position -within limits which may be takenby the latter.

This feature is important in that injury to the thread or detector is prevented in the event that a knot or other unusually large projection-on the thread engages the stirrup l2.

When the contacting arm 9 is rotated into engagement with the flexible contact l3, a circuit including the contacts will be completed which operates to control the potential of thecontrol grid ill of an electronic valve l9 which.

may desirably be a gaseous discharge valve, for example, an R. C. A. type 885. Valve l9 includes an anode 29, the control grid 2|, a cathode 22, and a

heater filament

2,3. Energizing voltage is supplied filament 23 from the secondary winding 24 of a transformer 25 having a primary winding 26 connected to the alternating voltage supply conductors L and L' In the operation of the electronic valve IS, a threshold discharge is initiated between the con- 4 ber 48, but is actuated in anupward trol grid 2| and cathode 22 when the grid potential relative to the cathode potential attains a predetermined value, depending upon the Critical grid-to-cathode voltage characteristic of the valve. The cathode-to-grid threshold discharge, when once initiated, is self supporting and if sufiicient voltage exists between the anode 28 and the grid 2| the said threshold discharge transfers to the anode, thus effecting a complete continuous discharge between the anode 28 and the cathode 22. This discharge continues to pass between the anode and cathode as long as the voltage impressed therebetween does not decrease below the critical break-off value for the valve. That is to say, the control grid 2| is then ineffective in controlling the discharge between the anode and cathode 22, and the discharge can only be st pped by decreasing the voltage between the anode and cathode to a value below the critical break-off value.

In accordance with my present invention the I potential of the control grid 2| is controlled by the contact arm 9 and contact l3 together with other means-to be described for initiating a discharge between the anode 28 and cathode 22, and the discharge that subsequently takes place is stopped by means responsive to that discharge which operates to reduce the voltage impressed between the anode and cathode below the critical break-ofi value. 4

When contact arm 9 is out of engagement with flexible contact I3, a negative potential suificient to render the valve non-conductive is maintained on the control grid 2| of valve l9, but when contact arm 9 engages contact I3, a portion of the negative potential on the control grid 2| is shunted out whereby the valve is rendered conductive.

The means for maintaininga negative bias on the control grid-2| of valve l9 and Ear varying the magnitude of that bias on engagement of contact arm 9 and contact |3 includes a pair of

batteries

21 and 28 and a fixed resistor 29. Eatteries 21 and 28 and resistor 29 are connected in a series circuit between the cathode 22 of valve I9 and control grid 2| which may be traced from the cathode 22 to a conductor 38,;the positive terminal of battery 21 and therethrough to the negative terminal, the positive terminal of battery 28 and therethrough to the negative terminal, resistor 29, and conductor 3| to the control grid 2| Contact l3 of the detector mechanism is connected by

conductors

32 and 3| to the control grid 2 I, and contact arm 9 is connected by a conductor 33 to the point of engagement of

batteries

21 and 28.

Thus, as will be clearly apparent, when contact arm 9 is out of engagement with contact l3, the combined potentials of

batteries

21 and 28 will be maintained between cathode 22 and control grid 2|, but upon engagement of contact arm 9 and contact |3-, battery 28 will be shunted out, and battery 21 only will be effective to negatively bias control grid 2|. Resistor 29 is provided to limit the value of current discharged by battery 28 to a low value when contact arm 9 and contact l3 are in engagement.

Anode voltage is supplied valve |9 from a battery 34 through a switch mechanism 35 comprising a fixed contact 38 and a flexible arm 31 which are normally in engagement but are adapted .to be moved out of engagement by a plunger 38 upon movement of the latter in an upward direction.

Plunger 38 comprises the core of a relay winding flexible spring mem- 39 and normally rests on a direction when the relay winding is energized and falls back upon the spring member 48 when the relay is deenergized. Flexible spring member 48 is arranged in cooperative relation with a suitable ribbon 42 and a recorder chart 43 for marking a dot on the chart each time the plunger 38 falls back thereon. A slight protrusion is formed in the spring member 48 for making a clearly defined dot on the chart.

As illustrated,spn'ng member 40 is mounted on the lower end of a metal post 4|] which is rigidly connected at its other end to one end of an insulating rectangular block 38 of Bakelite or other suitable material. A cylindrical tube 39 which may desirably be of brass, is inserted through an opening in the other end of block 38 and is fitted securelysthereto. Spring member 31 and contact '36 are mounted on the upper surface of block 38 as shown. Relay winding 39 is wound on tube 39 and plunger 38 is inserted in the tube 39 and is adapted to be guided thereby. A brass rod 4|, which extends axially of the plunger and is rigidly connected with theupper end thereof, is desirably provided to make it possible for the plunger to separate switch member 31 and contact 38, when actuated, without leaving the province of winding 39.

The recorder chart 43 is adapted to be driven by a continuously rotating roller 44 which may be driven in any convenient manner, as, for example, by a unidirectional electrical motor (not shown) so that any imperfections in the thread ,will be recorded on the chart as a series of contiguous marks on a straight line.

Relay winding 39 is connected in the output circult of valve [9 in series with the battery 34 andthe switch mechanism 35 so that when the valve I9 is rendered conductive as a result of impact of defective filaments with the detector stirrup l2, energizing current fiows through the relay winding. Plunger 38 is then actuated in an upward direction and rod 4|, which is integral therewith, strikes the switch arm 31 and quickly moves the latter out of engagement with the contact 38 whereupon the flow of anode current to valve I9 is interrupted and the plunger 38 falls back and strikes the flexible spring 40 causing the latter to make a. mark on the recorder chart through the ribbon 42. L

It is noted that normally a very short contact period between the contact arm 9 and the contact l3 of the detector mechanism results from impact of defective filaments on the stirrup l2 so that when plunger 38 interrupts the anode circuit of valve I9, the latter remains non-conductive until the detector mechanism is again actuated by impact of defective filaments. In the interim, plunger 38 is held off the recorder chart 43 by the flexible spring member 48 in readiness for the next marking operation It is noted that when an exceptionally bad defect strikes the detector stirrup l2, the contact arm 9 may be held in engagement with the contact I3 for a longer period whereupon the plunger 38 will be caused to make several closely spaced marks on the chart.

In Figs, 4 and 5 I have illustrated, more or less diagrammatically, a modification of my invention which may be employed for detecting the presence of defective filaments in a plurality of threads simultaneously and for recording the thread imperfectionson a single recorder chart. In this form of my invention a motor-generator set 45 employing a motor 46 energized from the alternating voltage supply conductors and a generator 41 driven thereby is provided for supplying direct 4 t a es current anode voltage to a plurality of valves l9 and a suitable rectifier unit 56 is provided for supplying a suitable negative bias for the valve control grids.

As illustrated in Fig. 4, a plurality of detector units i, la and lb are provided and a plurality of switch mechanisms 35, a and 35b, each of which includes an individual plunger 38in co operative relation with a recorder chart 43, are provided for recording the thread imperfections in the individual threads. The switch mechanisms 35 are mounted side by side in an instrument casing 48 of rectangular outline.

The casing 48 is formed with a doorway 49 at its front side, which is normally closed by a door 50 connected at one side to the casing body by hinges 5i. The door 50 is'provided at its opposite side with a knob 52, and is ordinarily provided with a locking means including a keyhole in the knob 52 for locking the door in its closed position. In addition to the

switch mechanisms

35, 35a and 35b,'casing 48. houses a recorder chart 43 and chart roll therefor which is driven by a continuously running unidirectional motor (not shown).

By virtue'of the fact that

switch mechanisms

35,3511 and 35b are of the type disclosed, a. relatively large number may be placed side by side in a narrow space whereby a compact unit is obtained. The system illustrated in Figs. 4 and 5, for example, is of commercial form in which twenty-four such devices are employed side by side in a space less than eleven inches wide.

As illustrated, the detector units Lia, and lb are connected by a cable to the terminal posts of an instrument casing 53 which houses a plurality of electronic valves I9, I91: and H17 and in the case of the form above mentioned, it houses twenty-four such valves. As is shown in detail in Fig. 5, all of the detector contact arms 9, 9a and 9b are connected .to'a common conductor 54 which is connected to a conductor 55 common to all of the cathodes of the valves. It

is noted the common cathode conductor 55 and the metallic cases housing the detector units may desirably be both connected to ground, for ex-' ample, to the winding machine frame 8, to ensure that engagement of the detector arms 9, 9a or 9b with their metallic casings will not result in operation of its associated recording mechanism, to thereby falsely indicate the presence of defective thread filaments.

In Fig. 5, in order to avoid confusion of the I drawings, I have shown a circuit for detecting the presence of defective filaments in only three threads but it will be understood that defective filaments may be detected in twenty-four or any additional number of threads, as desired, the, only limit as to the actual number being the load that the motor generator set 45 and the rectifier unit 56 can safely handle.

' In this arrangement, as mentioned hereinbefore, a suitable rectifier unit 56 energized from the alternating voltage supply conductors L and L has been provided for supplying negative bias to the ,control grids of valves I9, I91: and l9b in lieu of

batteries

21 and 28 which are employed in Fig. l for that purpose. The rectifier 56 includes an electronic valve 51 which may be a conventional full Wave rectifier,-having a pair of

anodes

58 and 59 and a filament cathode 60 connected by conductors 6| and B2 to the secondary winding 63 of a transformer 64. Transformer (it is a combination step-up and step-down transformer and includes a high voltage secondary winding 55, and low voltage secondary windings 63 and 66, and a line voltage primary winding 577 connected directly to the alternating voltage supply conductors L and L The anodes 58 and 5d of valve 51 are connected by

conductors

68 and 69 to the terminals of the transformer secondary winding 65, and the rectified anode current of the valve is connected across the terminals of a filtering condenser 70. A center tap on the secondary winding is connected by a conductor M to one terminal of the condenser l0 and the other terminal of the latter is connected to the filament cathode 60 so that a direct current voltage is maintained across the condenser 70. The

- positive terminal of the condenser .10 is con nected by a conductor T2 to the conductor 55 which is common to all the cathodes of the valves and the negative terminal of the condenser 10 is connected to each of the control grids thereof through a

respective resistance

29, 29a, and 29b.

As mentioned hereinbefore, the switch arms 9, 9a and 9b of the individual detector mechanisms are connected to the common cathode conductor 55. In addition each of the cooperating flexible contacts l3, l3a and [3b are connected to a respective valve control grid so that upon engagement of a switch contact arm with its associated contact, the negative bias on the corresponding control grid will be shunted out and that valve accordingly will be rendered conductive; Actuation of a

plunger

38, 38a or 38b associated with that valve as a result of energization of the particular relay winding connected in the anode circuit of that valve operates to deenergize the valve and to record the thread imperfection immediately thereafter by marking a dot on the recorder chart 43. For facilitating scanning the chart, the latter may be marked off into a number of divisions corresponding to the number of detector units being employed and each of the chartdivisions may be numbered to correspond with a detector unit so that imperfections in each of the individual threads will be recorded in a division of the chart numbered to correspond therewith.

As illustrated, a neon lamp 13 may be asso-'

ing

39, 39a and 39b and may be positioned directly in front of the switch mechanisms with which they are associated so that the thread or threads having the imperfection will be indicatedat a glance. Such visual indication is desirable in an instrument wherein a large number of detectors are employed so as to provide a more prominent visible indication of the thread condition at a distance greater than that at which the chart must be observed.

As illustrated, a switch 14 connected in circuit with the supply conductors L and L is provided for starting up and deenergizing the system. Closure of switch 14 results in energization of the motor-generator set 45 and also in energization of a suitable time delay device 15. Device l5 may be of any well known type and is adapted to control the energization of a relay 16 after a suitable time delay period, for example, two minutes. This time delay period is provided to ensure that the cathodes of valves I9, 15a and lilb are heated before voltage is impressed becathode results.

tween the anodes and cathodes thereof. In the operation of valves of this type, if anode voltage is impressed between the anode and cathode when the latter is cold or before it is up to its operating "temperature, rapid deterioration of the The time delay means and associated apparatus are employed, therefore, to prevent the occurrence of such deterioration,

An armature Tl associated with the relay 16 and biased by spring means 18 out of engagement with a contact 19 is moved into engagement with the latter against the opposing force of the spring when the relay is energized. Armature l1 and contact 19 are connected in the common cathode circuit of valves l9, Isa, and I91) and close that circuit when in engagement, but interrupt it when out of engagement. i

The heater filaments of valves [9, [9a and i917 are connected in a parallel circuit with each other and receive energizing current from the transformer secondary winding 66. Transformer 64 is energized immediately upon closure of the line switch 14 so that energizing current fiows at once to the heater filaments. The length of the time delay period is desirably made long enough to ensure that the cathodes of valves N, Na and l9b will be heated to their operating temperature so that at the 'end of the time delay period and subsequent closure of the common cathode circuit by the relay armature H, the valves will be in operating condition and no damage will result thereto.

Subject matter disclosed and not claimed in this application is being claimed in my copending application Serial No. 118,095 filed Dec. 29, 1936.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that certain features of my invention may sometimes be used to advantage without a corresponding use of other features. I

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is: d

1. In apparatus for detecting defective filaments in a' thread, detecting means disposed in the path of the thread and adapted to detect said detective filaments, means for relatively.

' moving said thread and said detecting means, a

source of electrical current, relay means, gaseous discharge valve means under control of said desaid circuit connection, and recording means controlled by said influencing means.

2. In apparatus for detecting defective filaments in a thread, detecting means disposed in the path of the thread and adapted to detect said defective filaments, means for relatively. moving said thread and said detecting means,

a source of direct current, relay means, gaseous discharge valve means under control of said detecting 'means, a circuit connection including said relay means, said gaseous discharge valve means, and said direct current source, means under control of said relay means to influence said circuit connection, and recording means controlled by said influencing means.

3. In apparatus for detecting defective fila ments in a thread, detecting means disposed in .the path of the thread and adapted to detect said defective filaments, means for relatively moving said thread and said detecting means, a source of direct current, relay means, gaseous discharge valve means under control of said detecting means, a circuit connection including said relay means, said gaseous discharge valve means, and said direct current source, means under'control of said relay means to interrupt said circuit connection, and recording means controlledby said interrupting means.

4. In apparatus for detecting defective filaments in a thread, detecting means disposed in the path of the thread, means for relatively movengaged at one end and rotated by defective filaments in said thread and adapted to engage an electrical contact with its otherend, and flexible spring meansior biasing said arm away from engagement with said electrical contact and for damping the oscillation of said arm.

6. In apparatus for detecting detective filaments in a thread a light arm pivoted intermediate its ends for oscillation and adapted to be engaged at one end and rotated by defective'filaments in said thread and'adapted to engage an electrical contact with its other end, and a pair oi. flexible fingers in engagement with said contact arm on either side thereof for biasing said arm away from engagement with said electrical contact and. for damping the oscillation of said arm. I

' EARL A. p