US2546617A - Electric weft detecting system for looms - Google Patents

Description

March 27, 1951 v, SEPAVlCH 2,546,617

ELECTRIC WEFT DETECTING SYSTEM FOR LOOMS Filed Dec. 2'7, 1948 J/ FIG.I

s5 B il9 l I 22 2s INVENTOR F I G 2 VICTOR E SEPA V/Gh' ATTORNEY Patented Mar. 27, 1951 UNITED STATES PATENT OFFICE ELECTRIC WEFT DETECTING SYSTEM FOR LOOMS Application December 27, 1948, Serial No. 67,339

This invention relates to electric weft detecting systems for looms and it is the general object of the invention to provide such a system with circuits which will energize the loom controlling electromagnetic device, such as a solenoid, for a short part only of the time elapsing between its energization and the time at which the loom uses the control exercised or indicated by the device.

Electric weft detecting systems for stopping looms generally employ some form of feeler or detector and a solenoid which positions one part of the loom, such as a knock-off mechanism, for operation by another part thereof. There is ordinarily an appreciable interval of time between indication of weft exhaustion by the weft detector and operation of this other part to effect a change in loom operation, such as loom stoppage. In electric weft detecting systems commonly used the solenoid is required to be energized throughout this entire period of time and because of this fact it has been necessary to use a solenoid large and expensive enough to withstand continued energization, even though a brief momentary energization is all that is required.

It is an important object of the present invention to provide an electric detecting system which includes a normally charged electric condenser for energization of the solenoid and means for discharging the condenser through the solenoid incident to indication of weft exhaustion. The solenoid is therefore energized for the brief interval of time only during which the condenser discharges.

A type of electric weft detector which has gone into general use employs a pair of detector fingers or prongs for engagement with a denuded metallic ferrule on the bobbin of a depleted weft shuttle. It has been found that these detector fingers are likely to rebound when they are struck by the metal ferrule so that the total amount of time during which the detecting circuit can be closed is materially less than that fraction of the cycle of the loom during which the fingers would contact the ferrule if there wer no rebounding. The amount of electric power which would otherwise pass through the detecting circuit is therefore reduced to an amount insufficient to operate arelay or the like and also charge a condenser.

It is a still further object of the invention to employ a normally closed charging circuit for the condenser and a relay responsive to very small currents which when energized by momentary closure of the detector circuit will connect the condenser to a discharge circuit including the 5 Claims. 01. 139370) solenoid andsimultaneously open the charging circuit so that current from a primary source, such as a transformer, cannot flow through the solenoid.

With these and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawings, wherein a convenient embodiment of the invention is set forth,-

Fig. 1 is a diagram of the electric circuits forming the subject matter of the present invention in their normal condition prior to indication of weft exhaustion, and

Fig. 2 is a View similar to Fig. 1 but showing the conditions which exist when the weft detector indicates Weft exhaustion.

- The invention is applicable to various types of' electromagnetic loom control systems not necessarily limited to stopping mechanisms, but is shown herein as applied to such a mechanism for the purpose of stopping loom operation upon exhaustion 0f weft. The stopping of the loom may be effected by means shown, for instance, in prior patents to Payne Nos. 1,873,465 and 2,266,474. The knock-off mechanism employs a cam l0 which may be on the bottom or two pick shaft of the loom to rock an actuator lever l I periodically during loom operation, usually at two-pick intervals. A knock-01f or stopping lever I2 is normally in non-stopping position during loom operation and has attached thereto a link l3 which is ordinarily in the down or non-stopping position thereof due to the fact that a solenoid S is normally deenergized and its core I4 is in low position. During normal running conditions the cam causes the lever H to have periodic work ing strokes to the left, but the link 13 will be down out of the path of the lever so that the stopping lever I2 will remain unchanged. If the solenoid is energized its core I4 is lifted to raise the link to stopping position. in the path of lever ll, whereupon the lever I2 is moved from non-' stopping position to stopping or knock-01f position to effect loom stoppage.

A weighted lock or holding detent I5 under turns to the right the detent is returned to its 7 normal non-supporting inclined position. For

further details of the detent reference may be had to the aforesaid Payne patents.

Detection of the condition of weft in the shuttle ordinarily occurs when the lay is at front center, but the cam I6 is usually set so that it will initiate loom stoppage later in the loom cycle and at a time which will permit complete loom stoppage before the next picking operation, which ordinarily occurs when the lay is at top center. There is therefore an appreciable interval of time lapsing between indication of weft exhaustion by the Weft detector and movement of the link by lever II. In the past the solenoid S has been maintained energized throughout this interval and because of this fact it has been necessary to employ a solenoid which could withstand continued energization.

The weft detector D employs right and left detector fingers l"! and I8 for cooperation with the metallic ferrule l9 on bobbin B. The bobbin is presented to. the detector by forward movement of th lay andwhen the ferrule is covered .with weftthe detector fingers fl and .I8 are insulated fromeach other; butwhen weft exhaustion occurs the ferrule is uncoveredand electrically connects the fingers; These fingers are ordinarily maintained in their normal rearward position by springs (notshown) which yield as: the fingers move forwardly.

When the metal ferrul strikes 'the'finger the latteriare likely to rebound, each detector, finger rebounding in a manner determined partly at east by its own spring; The rebounding of the, detector fingers is likelyto'be unequal'and one' finger may return to contact with the ferrule andstart a second rebound while the other finger due to its rebounding is still out of contact with the ferrule. flow through the detector for the period at least during which the fingers. fl and l8,rebound and are not .in simultaneous engagement with the ferrule. If the solenoid'is directly energized by the detector circuit thisrebounding may prevent its full energization and it is for this reason that a relay is employed which can be energized'by a much smaller current than would be required by the solenoid, this relay being inthe circuit of the detector and effectiv to establish contacts which control the circuits, associated with the solenoid when the detector indicates weft'exhaustion;

As-sliown for instance in Fig. 1, a transformer T supplying alternating electric current has leading therefrom line' wires- 20 and 2i, the latter being electrically connected by wire-22 to the detector finger i8. Finger I! is connected electrically by wire 23' to a contact 24 which normally engages-a contact plate 25 on but insulatedfrom the knock-off or stopping lever l2 when the latter is in its normal running or non-stopping position. A second contact 26 also engaging plate 25 is connected by wire 2'5" to a relay 28 connected by wire 29 to the other line Wire 26; This constitutes a detecting circuitwhicli is ordinarily open at the weft detector but'will be closed by simultane ous engagement of the two detector fingers l l and [8 with the ferrule 9, at whichtime the'detecting circuit will be closed and the relay will be energized to efiectclosure of certain contacts and openingof other cont-acts associated with it.

Because of thebriefness of closureof the detector circuitforreasonsalready described, particularly at hi h loom speeds, a holding circuit,

means is provided which bypassesor short cir cuits the weft detector. This circuit is asfollowsL line wire 28; wire 29, relay 23, wire 27, contact 26,

Under these conditions no. current cancontact plate 25, contact 24, wire 30, contact 3|, contact plate 32, (controlled by the relay), contact 33, wire 34, and wire 2| back to the transformer T. This holding circuit is maintained closed subsequent to the detecting period and after the ferrule :53 moves rearwardly away from the detector due to lay motion, and so long as lever i2 is in running position.

The solenoid is energized by a condenser C which is normally connected across the lines 20 and 2! by the following charging circuit: wires 21 and 35; contact 26, contact plate 3! (controlled by the relay), contact 38, wire 39, rectifier 40, wire 4%, condenser C, and wire 42 to the other line wire. 20; The plate, 3'! electrically connect the contacts 36 and33 when the relay 28 is deenergized so that the condenser C is normally connected across the transformer and in a fully charged condition. When relay 28 is energized, however, the plate 3'! moves away from the contacts 36 and 38 and opens or interrupts the charging circuit;-

The relay 23 alsocontrols the following solenoidor'condenser discharge circuit: condenser C, wire 4|, wire t5, solenoid S, wire 46, contact 41, cont-act'plate 48 (controlled by the relay), contact 49,,wire 50, and wire42 back to the con: denser. This circuits is normally open butwhen the rela 28 is energized to cause plate 48 to en,- gage contacts 4'? and 49, the discharge circuit is closed and, the condenser discharges through the solenoid to energize; it with resultant lifting of the link' IE. to its stopping position. The discharge circuit is connected to the charging circuitat a point between the, rectifier and the, condenser; but opening of the charging circuit by movement of ,plate 3'! away'from the-contacts,

and 38- prevents currentgfrom the transformer,

from passing toth solenoid or through the discharge circuit, and the solenoid willbeenergized tion,v to stopping position, one ofthe effects of which is vto stop the loom and another effect of whichis to move, contact plate 25 away from.

contacts 24 and 26. This results in opening the holdingcircuit and causing deenergizationof the relay 28. upon return from their indicating position shown in Fig. 2to their normalposition indicated in Fig. 1'.

From the foregoing it will'be seen that the detector system provides a normally charged condenser and, a normally open discharge circuit including a solenoid, together with means for,

closing the discharge circuitwhen the detector.

indicates weftexhaustion. The-solenoid'is associated with a part, such as link l3, which is moved to controlling or knock-off position when the solenoid is energized, and it is therefore not necessary to continue energization of thesolenoid beyond the time required to lift the link 13. The

condenser and solenoid have such electric char acteristics that the condenser is ableto maintain thesolenoid energized for several cycles of alter naLin-g current sufficiently long to perform its required work. The holdingcircuit will be-opened The contact plates 32, 3'! and there-- when the knock-off lever I2 moves to stopping position, whereupon the contacts controlled by the relay 28 return to their normal condition. While the switch including contacts 24 and 26 and the contact plate 25 has been shown herein as being opened by knock-off lever l2, it is apparent that the'invention is not limited to a particular part for controlling the switch. If desired a break in one or the other of the main line wires 20 or 2| could be effected by the shipper mechanism when moving to stopping position, but this has not been illustrated, since it is well understood. It will further be seen that a very brief contact established by the weft detector and ferrule l9 will sufiice to set the detector system into operation and that a considerable period of time can elapse between indication of weft exhaustion by the detector and the ultimate use which the loom makes of this indication, that use as specifically set forth herein being loom stoppage. The invention, however, is not to be limited to loom stoppage, since it will suflice if discharge of the normally charged condenser through the solenoid effects setting of some part of the loom to be followed by a change in loom operation.

Having thus described the invention it will be seen that changes and modifications of the foregoing specific disclosure may be made without departing from the spirit and scope of the invention.

What is claimed as new is:

1. In an electric weft detecting system for a loom having a source of alternating current electric power, an electric weft detector and mechanism effective to cause a change in loom operation when a solenoid is energized, said system comprising a charging circuit including a condenser, a normally closed switch and a rectifier, a discharge circuit including the condenser, solenoid and a normally open switch connected to the charging circuit between the rectifier and condenser, and electric means effective upon indication of weft exhaustion by the weft detector to open said normally closed switch to prevent flow of electric current from said source through the rectifier to the solenoid and close said normally open switch to energize the solenoid by electric power derived from the condenser only.

2. In an electric weft detecting system for a loom having a source of electric power, an electric weft detector and mechanism effective to cause a change in loom operation when a solenoid is energized, said system comprising an electric detecting circuit including a normally deenergized relay effective upon indication of weft exhaustion by the detector to energize the relay, a holding electric circuit completed through the relay and source upon energization of the relay, a normally closed electric charging circuit including the source and a condenser, a discharge circuit normally open including the condenser and solenoid, electric means acting due to energization of the relay to open the charging circuit and close the discharge circuit to cause energization of the solenoid by electric power derived from the condenser, and means acting subsequent to energization of the solenoid effective to open the holding circuit, whereupon the relay becomes deenergized, the charging circuit is closed and the discharge circuit is opened.

3. In an electric weft detecting system for a loom having a source of electric power, an electric weft detector which can indicate weft exhaustion at a given point only in the loom cycle and having mechanism effective at a later point in the loom cycle to cause a change in loom operation if a part thereof has previously been moved due to energization of a solenoid, the systern comprising a normally open electric detector circuit powered by said source and including the detector and a relay and closed to energize the relay when the detector indicates weft exhaustion at said given point in the loom cycle, an electric chargingcircuit including an electric condenser normally closed to charge to condenser by power derived from said source, a normally open electric discharge circuit connected to the charging circuit and including the solenoid and condenser, and electric means effective upon energization of the relay to close the discharge circuit to energize the solenoid by power derived from the condenser and open the charging circuit prior to said later point in the loom cycle to the end that the solenoid will be energized by power derived from the condenser only and move said part and become deenergized prior to said later point in the loom cycle.

4. In an electric weft detecting system for a loom having a source of electric power, an electric weft detector and stopping mechanism normally in non-stopping position but moving to stop the loom incident to but subsequent to energization of a normally deenergized solenoid, the system comprising an electric detecting circuit powered by said source and including a relay and a switch normally closed when the stopping mechanism is in non-stopping position and closed to energize the relay when the weft detector indicates weft exhaustion, a normally open holding electric circuit powered by said source including said switch and relay and closed as a result of energization of the relay, a normally closed charging electric circuit including an electric condenser powered by said source to keep said condenser normally charged, means opening said charging circuit as a result of energization of the relay, and a normally open discharge electric circuit including the condenser and solenoid closed as a result of energization of the relay to energize the solenoid by the condenser only and independently of said source, movement of the stopping mechanism to stopping position due to energization of the solenoid opening said switch and holding circuit with resultant deenergization of the relay and closure of the charging circuit and opening of the discharge circuit.

5. In an electric weft detecting system for a loom havinga source of electric power and an electric weft detector which is capable of indicating weft exhaustion, the loom having a periodically rocking actuator lever, a knock-off lever, and a link operatively connected to the knockoff lever normally out of operative position relatively to the actuator lever but moved into op erative position with respect to the actuator lever when a solenoid is energized, a holding detent operative upon movement of the link to operative position with respect to the actuator lever to move to holding position to maintain said link in said operative position relative to the actuator lever, the system comprising a normally open electric detector circuit powered by said source and including the detector and a relay closed to energize the relay when the detector indicates weft exhaustion, an electric charging circuit including an electric condenser normally closed to charge the condenser by power derived from said source, a normally open electric discharge circuit connected to the charging circuit and in- 7 8 cluding the solenoid and condenser, and electric REFERENCES CITED means effective upon energization of the relay to The following references are of record in the close the dischaIC-Ige circufit to irl lergiize'tthe soleme of this patent; noid by power erived' rom e eec ric condenser a sufiicient length of time to enable said 5 UNITED STATES PATENTS holding detent to move to the holding position Number Name Date thereof relative to the link, said holding detent 2,086,913 'Kelly Mar. 14, 1931 remaining. in the holding position thereof sub- 2,429,530 Sepavich et al. Oct. 21, 1947 sequent to complete discharge of the condenser to maintain said link in the path of said actuator 10 lever.

VICTOR F. SEPAVICH.

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