US2026146A - Light actuated weft detector for looms - Google Patents

Description

Dec. 31, 1935. R. a. TURNER LIGHT ACTUATED WEFT DETECTOR FOR LOOMS Filed April 16. 1934 3 SheetsSh eet 1 noentor Richard. GITurner (lttorness Dec. 31, 1935. R, NE I 2,026,146

LIGHT ACTUATED WEFT DETECTOR FOR LOOMS Filed April 16. 1934 Sheets-Sheet 2 v 13 orne v l-vr s Richard GITur-nev R.G.TURNER LIGHT ACTUATED WEFT DETECTOR FOR LOOMS Dec. 31, 1935.

Filed April 16. 1954 3 Sheets-Sheet 3 I mgentor Rmhard G-Tu'rner Qttorngys I Patented Dec. 31,1935

L IGHT ACTUATED WEFT DETECTOR FOR LOOMS Richard Greenleaf Turner, Worcester, Mass., as-

signor to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachib.

setts Application April 16,1934, Serial No. 720,739

30 Claims.

This invention relates to weft detectors for looms and it is the general object of the invention to provide a detector which will operate without subjecting the yarn being detected to any appreciable pressure so that the physical characteristics of the yarn are unaffected by the detecting operation.

Most weft detectors for looms operate by establishing contact between the mass of weft being detected and some physical agent of appreciable weight. These repeated contacts abrade fine yarns and change their quality to such an extent that they will produce a rough or noticeable place in the cloth in which they are incorporated. Most electrical weft detectors have an electrode which engages or is positioned by theyarn and the lightest of the mechanical detectors heretofore proposed are likely to produce a noticeable efiect on very fine yarns. There is a relation between t the size of yarn and the length of it which can be wound on a bobbin, the finer the yarn the greater the length. A bobbin of fine yarn will remain in action a comparatively long time, so that the wearing is due not only to the size but also the length of time the yarn is subjected to the detecting operation.

It has been proposed heretofore to employ a blast of air to blow through a specially constructed bobbin, the blast being blocked off while 0 yarn is present, but being transmitted through an exhausted bobbin to move a control vane. These pneumatic detectors have never attained any wide use. Dust floating near the blast is likely to be drawn in and directed toward the yarn, resulting in discoloration.

Magnetic detectors having a magnetized part .to engage and be attracted by a ferrous ferrule on the bobbin have been employed but actual yielding contact between the magnetized. detector and the weft has been necessary in order to have the magnetic attraction sufiiciently strong to operate when exhaustion approaches. All of these types of detectors contemplate theconta'ct of a physical medium with the weft.

In an attempt to produce a weft detector much more delicate than any heretofore proposed I have experimented with a photo-electric eye which is rendered operative to eifecta change in the loom operation by meansfof light variation induced by a change in the condition of the weft.

In my experiments I mounted a source of light in front of the lay adjacent the-photo-electric eye and employed a bobbin having a ferrule with a highly polished surface. I found that for practi- ,cally all sizes and colors of yarn it was possible excitation of a photoelectric cell by a change in to bring the lay adjacent the source and eye without operating the latter so long as a weaving supply was present, but as soon as the diminishing weft uncovered the polished ferrule the latter re-' fiected light to the eye to bring about a change 5 in loom operation, such, for instance, as changing o'f shuttles.::-

My invention is not limited, however, to use of reflected light, since any arrangement which will cause a change in' the light falling on the 10 senstive eye can be made to operate the latter and control the loom. In co-pending application Serial No. 722,551 I show and claim a source of light directed toward the eye and blocked until sufficient weft has been unwound to allow the 15 light to shine through the bobbin or shuttle to actuate the eye.

My invention relates therefore generally to a detector depending upon its operation for the the light intensity falling upon it induced by an alteration in the condition or amount or weft being detected without regard to the position of the source of the exciting light ray.

A detector of this kind can be adapted for use with a bobbin changing loom, a shuttle changing loom, or a loom provided with means to stop it when the running weft reaches a given condition. As illustrated in more detail hereinafter I have shown my invention in connection with a multi- 30 color bobbin changer, a single color shuttle changer, and a loom which stops when the weft is substantially exhausted.

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

'In the accompanying drawings, where three forms of the invention are shown,

Fig. 1 is a front elevation of the preferred form of the invention, showing a loom having a shuttle changer at one end and weft detecting mechanism at the other, made according to my present invention,

Fig. 2 is a detailed view on an enlarged scale of the lower part of the left hand side of the loom shown in Fig. 1, looking in the direction of arrow 2, Fig. 1,

Fig. 3 is a vertical section on line 3-3 of Fig. 2,

Fig. 4 is a top plan on an enlarged scale of the right hand part of Fig. 1, looking in the direction of arrow 4, Fig. 1,

Fig. 5 shows the first modification of my invention and is an end elevation of part of the loom 55 adapted to effect loom stoppage by means of my present invention,

Fig. 6 shows the second modification of my invention and is a vertical section through a fourcolor bobbin changing magazine with the lay and detector,

Fig. '7 is an'enlarged view similar to a portion of Fig. 6 showing the switch which is used to prevent a repeated indication on transferring beats of the loom,

Fig. 8 is a view showing the front of the magazine such as that shown in Fig. 6 with the detector mechanism and control parts shown in greater detail and on a larger scale,-

Fig. 9 is a diagrammatic view showing the circuits including the source of light, photo-electric tube, the relay, and the loom controlling solenoid,

Fig. 10 is a detail of a modification of part of Fig. 9 used when the detector is employed on the bobbin changer type of loom, and

Fig. 11 is a detail vertical section on line I, Fig. 6.

Referring to the drawings, the preferred form of the invention, set forth particularly in Figs. 1 2 and 3, relates to a shuttle changer of the single color type. The loom frame l5 has a lay l6 mounted on swords l1 and carrying'a reed I8. A picker stick I9 suitably actuated by well-known mechanism not shown herein propels the shuttle 8 across the lay from the shuttle box 20 on the right hand side to an upper shuttle box 2| on the left hand side of the lay. So long as suflicient weft is present the box 2| is in lowered position in alignment with the shuttle race 22. The left hand picker stick 23 returns the shuttle to box 20. A magazine M is provided with a stack of reserve shuttles 24 which are normally positioned on a movable support or platform'25.

Beneath the box 2| is an auxiliary shuttle box 26 which is normally unoccupied but which can be raised by box rod 21 so that when a shuttle change is to take place the upper box 2| will be elevated to a position where it can receive the lowest shuttle of the'stack of reserve shuttles, and where the oncoming depleted shuttle will enter the lower auxiliary box 23. Thereafter the boxes 2| and 2B will'be lowered so that the upper box will return to normal picking position in time to pick the fresh shuttle across the loom from the left hand side.

These vertical motions of the boxes 2| and 26 may be accomplished by means of a cam C which gives regular operating movements to a lever 28 having a notch 29. The latter normally clears a latch 30 which is in the dotted line position shown in Fig. 3 when sufiicient weft for continued weaving is present. The latch is mounted .on a lever 3| attached to a two-part yielding lifting link 32 the lower end of which is connected as at 33 to the box lifter rod 21.

As heretofore constructed the latch has been operated mechanically but when adapted for use in my present invention I provide an electromagnetic control including a solenoid 34 carried preferably by an arm 35 on the lever 3| and having a core 36 attached to a finger 31 projecting upwardly from the latch. A light spring 38 tends normally to hold the latch in the dotted line position of Fig. 3, and when the solenoid is energized it will attract its core, moving the same to the full line position shown in Fig. 3 to rock the latch in a counter-clockwise direction against the action of spring 38, moving it into the path of the rising notch 29. Upward movement of the forward end of lever 28 occurs immediate y thereafter to effect a rising movement of lever 3| and rod 21.

Further reference may be had to patent to Chevrette No. 1, 811,426 for details of a magazine which may be set into operation by movement of a part similar to latch 3|. As set forth herein the mechanical control of the Chevrette patent is replaced by the solenoid 34.

The second form of the invention relates to a loo'm which stops upon exhaustion of weft and may operate in a manner indicated in Fig. 5. The bottom shaft 40 carries a cam 4| which effects oscillation of a lever 42 having a pushing finger 43. A solenoid 44 has a core 45 pivoted to a thrust link 46 which in turn is pivoted to an upstanding arm 41. The latter is pivoted as at 48 to a fixed part of the loom while the upper end of the link is connected to a rod 49 operatively related to the shipper handle 50 of the loom. A holding dog 5| may be pivoted under the thrust link 46 during normal loom operation, as shown in Fig. 5.

So long as the solenoid is deenergized the pushing finger 43 will move to the left as viewed in Fig. 5 above the thrustlink without engaging the latter. When the solenoid is energized at the time of weft depletion, however, its core 45 will be raised to cause the thrust link 46 to lie in the path of the finger 43 and as the latter moves to the left its forcewill be transmitted to the arm 41 which, acting through the rod 49, will rock the shipper handle 59 in a clockwise direction and thereby stop the loom.

The details of the structure employed in the second adaptation of my invention of themselves form no part of my present invention and may be substantially as shown in patent to Payne No. 1,873,465.

In the form of my invention set forth in Figs. 6 to 8 and 10, inclusive, I show a loom frame 60 having a bobbin magazine 6|, provided in the present instance with four vertical stacks. 62, of reserve bobbins. Cradles 63 are provided, one for each stack, and they operate normally to support the bobbins but can be rocked by vertical slides one of which is indicated at 64 in Fig. 8.

The transferrer lever 65 is pivoted about a fixed stud 66 and has attached thereto a latch 61 notched to engage a hunter 68 carried by the lay 69. The latch has a forward loop 10 to cooperate With the lower end of a depressor rod II the upper end of which is connected to an arm 12 of a latch controller 13, see Fig. 11.

As shown in Fig. 8 there is provided a regularly vertically reciprocating rod 15 to the upper end of which is pivoted actuator lever 16 from which rises a rod 11. The latter is operatively connected to a color slide 18 having fingers 19 which lie between lugs on the previously mentioned upright slide 64. By means of well-known connections not shown herein the color slide is given a vertical motion .to align it with one or another of thaslides 64, depending upon which shuttle is active.

A controller 8| pivoted at 82 is normally held yieldingly in the dotted line position shown in Fig. 8 by a light spring 14 so that downward movement of the right hand end of the actuator lever 16 is unobstructed. A solenoid 83 has a III) either in patent to Ryon 1,030,748 or patent to Wattle 1,786,688. The usual mode of moving the controller is by a mechanical connection from the weft detector and the solenoid shown herein is a variation from previous practice, but the parts are otherwise as usual both as to structure and mode of operation.

In each of these adptations there is an electromagnetic device, such as the solenoid, to control loom operation. The solenoid is in each instance to be actuated by current caused to flow by the weft detector forming the subject matter of my present invention.

As shown in Fig. 4 a bracket 90 projects laterally from the loom frame and supports a housing 9| having a source of light 92, which may be an ordinary incandescent electric lamp and a photo-electric cell or eye 93. A partition 94 shields the eye from the lamp. The rear wall 95 of the housing has two openings 98 and 91 in alignment respectively with the source of light and the cell. The shuttle S has a. front wall .98 slotted at 99 and carries a bobbin IIIII provided with a'ferrule IIII having a reflective surface, such as chromium plating over nickel. The weft W as shown in Fig. 4 is substantially exhausted except for a slight reserve bunch R, and the ferrule IOI is therefore uncovered.

During loom operation the lay swings back and forth and the shuttle will enter the shuttle box B as the lay is moving forwardly and reaches so-called bottom center or protection. Continued fo'rward motion of the lay will advance the shuttle toward the detector, and light emanating from the lamp 92 will pass through the opening 96 and fall on the uncovered ferrule, traveling along a path sugested by line A. Some of this light will be reflected along a path indicated by line D to the photo-cell 93. The latter will thereupon be excited and set into action electric forces whichwill result in the actuation of one or another of the controlling solenoids. I have found that the device can be set so that excitation of the photo-electric eye will not occur until the lay reaches a desired given point in its forward travel. Such a controlis desirable scribed, may be used when a loom is to be stopped.

In the third adaptation shown particularly in Fig. 8 a housing I95 is supported by and depends from a tie rod I06 of the magazine frame and has a source of light I01 arranged to direct light through a slot I08 in the shuttle S toward the ferrule I09 within the shuttle. In a manner similar to that set forth in Fig. 4 light will be reflectd back toward a photoelectric cell I I contained in the housing J and shielded from the lamp II'II by a partition III.

y The photo-electric cell is therefore mounted substantially with respect to the magazine and forward motion of the lay brings the reflecting surface within the range of the source of light sufiiciently so that the reflected beam will be strong enough to energize the electric eye. 'By reference to Fig. 4 it will be seen that the beam of light A is directed rearwardly and obliquely with respect to the weft carrier I90 and is reflected forwardly and obliquely with respect to the carrier by the ferrule when weft is substantially exhausted. Any excess heat which may be de- 5 veloped by the illuminant I91 may escape through vents H2.

The electric circuits in themselves form no part of my present invention and although I illustrate in Fig. 9 one way of electrically connecting the 10 solenoid with the other parts of the circuit, yet any desired type of electric wirin'g can be interposed between the photo-electric cell and the solenoid which controls the loom.

Power wires H5 and H6 are connected to the light bulb 92 as shown in Fig. 9, although bulb I01 shown in Fig. 8 could replace bulb 92. This bulb may be illuminated constantly, although this I is not an essential feature, and it is suflicient for the purposes of the present invention if it is shining at those times when detection is desired. Wires II! and H8 connect one side of the line IIG with the primary of a transformer T the other side of whichis connected by wires H9 and. I29 to the opposite side of the line II5. Secondaries I2I, I22 and I23 are excited by the primary T, secondary I2I feeding the potentiometer I24 one side of which may be connected by wire I25 to the photo-electric tube or eye designated generally at E. The secondaries I22 and I23 may be connected as shown to a. pliotron tube and the latter is connected to the photo-tube, represented in Fig. 9 at 93, although any of the tubes described herein could be substituted for tube 93. The pliotron tube Q controls the winding I26 of ,a relay I 21 in such a way that when current flows through this winding by operation of the photo-electric eye and the pliotron tube an armature I28 will move into-engagement with contact I29, whereupon current will flow from power line H5, wire I20, wire I30, contact I29, armature I28, wire I3I, wire I32, solenoid M, which in the present instance is that shown in Fig. 5, wire I33 to wire Ill and thence back to the opposite side of the line I I6. Current flowing in this circuit excites the solenoid to produce the operations previously described. As already stated I do not wish to be limited to any particular control circuits between the photo-elec tric cell and the relay or solenoid. A relay will ordinarily be used because the current which can be built up bythe pliotron tube will not be suflicient to energize the solenoid. The wiring of Fig. 9 is merely for illustrative purposes.

In the operation of certain automatic looms it 5 is desirable to prevent a repeated indication on the transferring beat and this is particularly true in the bobbin changers such as setforth in Figs. 6 and 8. Bobbin changers of the type set forth herein willdetect when the exhausted shuttle is on'the magazine side of the loom, after which the depleted shuttle will be picked to the opposite side of the l'oom and returned again on a later pick. On return it will move forwardly and the depleted shuttle will come within 6 the range of operation of the photo-electric eye before the fresh bobbin can push the depleted bobbin out of the shuttle. This is particularly true if the potentiometer is set so as to pick up the indication when the lay is at a relatively considerable distance behind front center.

i The circuits illustrated in Fig. 9 are usable more particularly where there is no danger of repeating the indication of exhaustion by the detector., In the bobbin changer shown in Figs.

6 and 8, however, the exhausted shuttle returns to the detector side of the loom for replenishment, and there is a possibility of a second and undesired operation of'the solenoid 83. To prevent this effect, I modify that part of the circuit leading to the solenoid by adding a switch I40 having upper and lower arms I M and I42 held in an insulated holder I43, see Figs. 6, 7 and 10. As shown therein the wire I33 will have ;two branches I33a and I33?) which will terminate in the electrodes MI and I42, respectively. When the magazine is in normal position the rod II will be raised so that the bottom electrode I42 will contact with the upper electrode and current .can therefore flow through the solenoid. When the loom is set for transfer by depressing rod II, however, an insulated pad I45 adjustably mounted on a finger I46 secured to the rod II will move down so that the lower electrode will spring down away from part I4I, breaking the circuit to the solenoid, and even though the photo-electric cell should actuate the relay on the transferring beat of the loom, yet the solenoid cannot be energized. I do not wish to be limited to this particular'method of interrupting a control circuit.

In the drawings I have shown a form of photoelectric tube whichrelies for its operation upon a stream of electrons passing between an electrode and a plate within the tube. I do not wish to be limited to this particular kind of light sensitive element, however, inasmuch as other types of units responsive to light are known. For instance, there is the so-called voltaic cell which depends for its operation upon the fact that when the illumination of the juncture of two dissimilar metals varies a current is set up which can be magnified. In this instance there may also be a change in the temperature of the unit. Still other units are known in which the variation of light varies the electrical resistance of a conductor, as is the case with the selenium cells. Inasmuch as I believe that I am the first to use a weft detector which depends for its indication of weft exhaustion upon a change of illumination thereof I do not wish to be limited to the particular form of detector set forth herein. It is to be understood that in all ordinary forms of light there are heat rays which accompany the light rays and I consider that my invention is of such scope as to cover a detector which responds to a change in any of the forms of radiation which accompany a beam of light.

From the foregoing it will be seen that I have provided an electric weft detector of extreme sensitivity operating without material contact with the surface being detected. This result is achieved by the use of a photo-electric tube or cell sensitive to light used in conjunction with contrivances which act to vary the conditionof the cell by a change in the condition of the weft being detected. This type of detector can be used as set forth hereinbefore in shuttle or bobbin changing looms or in looms which are stopped when a predetermined condition of weft exists in the running shuttle. It will further be seen that I have provided means for preventing a repetition in indication of exhaustion when such an indication could be given, as for instance, in a multicolor bobbin changing loom where the depleted shuttle returns to the detector side of the loom in order to be replenished. It will also be seen that the path of light traversed by the reflected beam is angular, a condition which I do not deem essential but which existed in certain of the experiments which I performed. My inmade therein by those skilled in the art without 10 departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is:

1. In a loom, a supply of weft which becomes depleted as weaving continues, a light sensitive detector element effective when subjected to a change in illumination to cause a change in loom operation with respect to the supply of weft, and means to cause a change in the illumination of the element as weft depletion approaches, said means rendered ineffective to cause said change in illumination by presence of weft.

2. In a loom, a supply of weft which becomes depleted as weaving continues, a light sensitive detector element effective when subjected to a change in illumination to cause a change in loom operation, a lay to carry the supply of weft toward and from the light sensitive detector, and lay carried means to direct an actuating beam of light toward the detector when weft depletion approaches.

3. In a loom, a light-responsive device effective when receiving an energizing beam of light to complete an electric circuit through which a change in the operation of said loom is brought about, and means rendered effective by exhaustion of weft-in a shuttle being detected to cause an energizing beam of light to fall on said device.

4. In a loom, a light-responsive device effective when receiving an actuating beam of light to complete an electric circuit through which a. change in the operation of said loom is brought about, and means tending normally to cause an actuating beam of light to fall on said device at the time of weft detection but prevented from 6.0- ing so by presence of weft.

5. In a loom, a lay having a weft supply which is consumed by loom operation, a light-responsive device effective when receiving an actuating beam of light to produce a change in loom operation, and means by which movement of the lay when the weft supply is substantially depleted causes an actuating beam of light to fall on saiddevice.

6. In a loom, a light responsive device effective when actuated by a beam of light to cause -a change in loom operation, a source of light, a lay carrying a supply of weft, and means by virtue of which the combined motion of the lay together with depletion of the weft supply causes an actuating beam of light to fall on the device.

'7. In a 100m, a light responsive device effective when actuated by a beam of light to cause a change in loom operation, a source of light, and means by which depletion of weft renders the source of light effective to actuate the light responsive device.

8. A photo-electric loom weft detector rendered operative to indicate weft exhaustion by variation in a light beam directed toward the detector and induced by a change in the amount of the weft being detected.

9. In a loom, a lay, a supply of weft carried thereby, a light responsive element effective when actuated by a beam of light of given intensity to cause a change in loom operation, and means carried by the lay toward the element and effective when weft depletion approaches to direct a beam of light toward the element, motion of the lay toward the element increasing the intensity of the beam oflight.

10. In a loom, a" weft carrier having a lightreflecting surface which is progressively uncovered as substantial weft exhaustion. approaches, means to direct a light beam against said refleeting surface while said weft carrier is in an associated shuttle box, and a light-responsive device positioned to receive the reflected light beam and to be energized thereby to effect a change in loom operation.

11. In a loom, a weft carrier having a lightreflecting surface which is progressively uncovered as substantial weft exhaustion approaches,

means to direct a light beam against said reflecting surface while said weft carrier is in an associated shuttle box, and a light-responsive device positioned to receive the reflected light beam and to be energized thereby to complete an electric circuit through which a change in the operation of said loom is effected.

12. In a loom, a weft carrier having a lightreflecting surface which is progressively uncovered as substantial weft exhaustion approaches, means to direct a light beam against said reflecting surface while said weft carrier is in a shuttle in an associated shuttle box, and a lightresponsive device positioned to receive the reflected light beam and to be energized thereby to prevent complete exhaustion of weft on said weft carrier.

13. In a loom, a weft carrier having a light reflecting surface which is progressively uncovered as substantial weft exhaustion approaches, a source of light, a casing therefor having a rearwardly directed opening, a light-controlled relay controlling loom operation, acasing therefor also having a .rearwardly directed opening, and means to support said casings at such selected and relative angles that a beam from said source of light passing through the rearwardly directed opening of the light casing will be reflected by the surface of said weft carrier through the rearwardly directed. opening associated with the light-controlled relay.

M. In a loom, a weft carrier having alightreflecting surface which is progressively uncovered as substantial weft exhaustion approaches, a source of light, a casing therefor having a rearwardly directed opening, a light-controlled relay controlling loom operation, a casing therefor also having a rearwardly directed opening, means to support said casings at such selected and relative angles that a beam from said source of light passing through the rearwardly directed opening of the light casing will be reflected by the surface of said weft carrier through the rearwardly directed opening associated with the lightcontrolled relay, and means to adjust said supporting means forward and rearward in said loom.

15. In a loom having a shuttle box with a slot in one side and having a shuttle with a slot aligned with said first slot when said shuttle is in said shuttle box, in combination, a weft carrier in said shuttle having a light-reflecting surface which is progressively uncovered as substantial weft exhaustion approaches, means to direct a light beam through said slots and against said reflecting surface while said shuttle and weft carrier are in said shuttle box, and a light responsive device positioned to receive said light beam when reflected outward through said slots and energized thereby to effect a change in loom operation.

16. In a loom, a weft carrier having a light- 5 reflecting surface which is progressively uncovered as substantial weft exhaustion approaches, means to direct a light beam against said reflecting surface while said weft carrier is in an associated shuttle box and at an acute angle to 10 the axis of said weft carrier, said beam being reflected therefrom at a similar but opposite angle, and a light-responsive device positioned to receive the reflected light beam and to be energized thereby to effect a change in loom operl5 ation.

17. In a loom operating with a weaving shuttle having a supply of weft, shuttle changing mechanism to replace the weaving shuttle with a fresh shuttle, and a photo-electric weft de-v tector effective upon depletion of weft in the weaving shuttle to actuate the shuttle changing mechanism.

18. In a loom operating with a weaving shuttle having a supply of weft, mechanism to renew 25 the weft supply in the shuttle, and a photo-electrio weft detector effective upon depletion of weft in the weaving shuttle to actuate the said mechanism.

19. In a loom operating with a supply of weft means to stop the loom, and a photo-electric weft detector effective upon depletion of the supply source of light, and means by virtue of which the illumination thereof is changed to initiate a change in loom operation, a source of light, and meanscarried by the lay and dependent upon substantial exhaustion of weft to reflect light from the source toward the detector to change the illumination thereof.

.24. In aloom, a weft detector effective when the illumination thereof is increased to initiate a change in loom operation, and means dependent upon substantial weft exhaustion to cause an increase in illumination of the detector.

25. In a loom, a weft detector effective when the illumination thereof is changed to initiate a change in loom operation, a constant source of light, and means by virtue of which substantial exhaustion of weft causes light from the source 70 to change the illumination of the detector.

26. In a loom, a lay carrying a supply of weft,

a weft detector effective when the illumination thereof is changed to initiatea change in loom operation, a constant source of light, and means dependent upon substantial exhaustion of weft and motion of the lay to direct light from thesource toward the detector in sufiiclent amount to change the illumination thereof.

27. In a weft detector for a loom, a shuttle having a substantially cylindrical surface to be uncovered by weft at weft exhaustion, a photoelectric detector, 2. source of light positioned to direct a beam of light-on the cylindrical surface, the reflected beam of light leaving the surface being partly in a plane, and sensitive elements forming part of the detector lying in the plane.

' 28. In a loom, a weft detector eflective upon a change of illumination thereof to initiate a change in loom operation, a shuttle box to receive a supply of weft, and a source of light, said shuttle box constructed to define a. passage for light from the source to the detector when the weft supply in the shuttle box is substantially 20 exhausted. 1

29. In a loom having a lay to move a weft carrier backwardly and forwardly, means to direct a beam of light rearwardly and obliquely to the weft carrier, means on the weft carrier effective at substantial exhaustion of weft to reflect the 5 beam of light forwardly and obliquely, and a photo-electric weft detector located forwardly of the carrier and in a position to receive the reflected beam of light when the lay reaches a predetermined position in its motion.

30. In a loom, a weft detector effective upon a change of illumination thereof to initiate a change in loom operation, a source of light tending always to send light toward the detector, and means to interrupt the light to prevent the latter from falling on the detector except at the time of detection.

RICHARD GREENLEAF TURNER. 20

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