US2766781A

US2766781A - Photoelectrically controlled protection means for loom

Info

Publication number: US2766781A
Application number: US227844A
Authority: US
Inventors: Laraia Artemio; Victor F Sepavich
Original assignee: Crompton and Knowles Corp
Current assignee: Crompton and Knowles Corp
Priority date: 1951-05-23
Filing date: 1951-05-23
Publication date: 1956-10-16
Anticipated expiration: 1973-10-16

Description

Oct. 16, 1956 A. LARAIA ETAL 2,756,781

PHOTOELECTRICALLY CONTROLLED PROTECTION MEANS FOR LOOM Filed May 23. 1951 2 Shets-Sheet 1 FEGJ INVENTORS ARTEMIO LARAIA VICTOR F. SEPAVICH ATTORNEY Oct. 16, 1956 A. LARAIA ETAL 2,766,781

PHOTOELECTRICALLY CONTROLLED PROTECTION MEANS FOR LOOM Filed May 23. 195] 2 Sheets-Sheet 2 INVENTORS ARTEMIO LARAIA VICTOR F.SEPAVIGH ATTORNEY.

United States Patent M PHOTOELECTRICALLY CONTROLLED PROTEC- TION lVIEANS FOR LOOM Artemio Laraia and Victor F. Sepavich, Worcester, Mass., assignors to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application May '23, 1951, Serial No. 227,844

7 Claims. (Cl. 139-341) This invention relates to improvements in protection means for looms and it is the general object of the inven-' tion to control loom operation by a photoelectric cell the illumination of which at a critical time in the loom cycle is determined by the position of the shuttle along its path of flight, the loom being permitted to continue in operation if the shuttle is running on time but being stopped if the shuttle is running late.

The usual protection in fly shuttle looms includes a protector rod having one or more daggers and fingers for engagement with the shuttle binders in the shuttle boxes. The daggers are ordinarily in stopping position but timely arrival of the shuttle at a shuttle box acts through the protector fingers to move the daggers away from stopping position to permit continued loom operation. Such mechanisms require that the shuttle actually reach the shuttle box before an indication for continued loom operation can be given, but in fast running looms this indication comes so late in the cycle of the loom that if stoppage is necessary to prevent the shuttle from being pushed into the warp threads by the reed the stopping action must be very abrupt and is likely to cause damage to some part of the loom.

It is an important object of the present invention to be able to determine in advance of actual arrival of the shutshuttle at the shuttle box whether or not it is running on time and to effect this determination by causing the shuttle if running properly to effect a change in the illumination of a photoelectric cell at a given time in the loom cycle. If the shuttle is running late it will not be able to effect this change at the given time and electrically controlled means will then initiate loom stoppage earlier in theflight of the shuttle than is possible with the ordinary protection mechanism.

It is a further object of the invention to direct a beam of light through the top and bottom sheets of warp threads which form the warp shed of the loom toward the shuttle path and rely upon shuttle presence in the warp shed at the beam of light to alter the amount of light falling on the photoelectric cell for the purpose of effecting continued loom operation. It is found that although the warp threads cast some shadow it is not sufficient to interfere with adequate illumination of the photoelectric cell. This condition is believed to be due partly at least to the fact that some of the warp threads will be in the top sheet and the remainder in the bottom sheet so that the beam of light at the critical time in the loom cycle when indication of shuttle presence is given is not required to pass through a single sheet of warp threads such as might cast sufiicient shadow to interferewith correct operation.

The aforesaid change in illumination may be either a decrease or an increase in the amount of light falling on the photoelectric cell. When decreased illumination is utilized the shuttle will cast a shadow on the photoelectric cell, and when increased illumination is utilized a reflector on the shuttle will deflect a beam of light toward the photoelectric cell.

The ordinary shuttle used in fly shuttle looms will have solid ends one of which will carry a shuttle eye and the other of which may carry a bobbin clip to hold a bobbin extending between the ends of the shuttle. The bobbin is ordinarily centrally located transversely of the shuttle and it is a further object of the invention when utilizing decreased illumination of the photoelectric cell to locate the beam of light so that it will be interrupted not only by the solid ends of the shuttle but also by the bolgbin even though-the latter is substantially depleted of we t.

When reliance is placed on a decrease of light falling on the cell to effect continued loom operation the filament of the source of light may burn out or otherwise fail, in which event a condition will eXist equivalent to the casting of a shadow on the photoelectric cell and under these conditions the loom would be without protection. In order to guard against this contingency it is a further object of the invention to employ a control circuit which is dependent for its closure upon continued flow of current through the lamp, and if the filament of the latter should break the circuit will be open and cause prompt loom stoppage.

When increased illumination is relied upon to eifect continued loomrunning the photoelectric cell will be out of the normal path of the beam of light and the shuttle will be provided with a reflecting surface which crosses the beam of light and deflects it toward the cell.

Whether decreased or increased illumination of the cell is utilized the shuttle must be present at the beam of light to cause the aforesaid change in the amount of light falling on the cell.

In order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example two embodiments of the invention and in which:

Fig. l is a front elevation of the loom, parts being broken away, having applied thereto the preferred form of the invention'which relies upon decreased illumination of the photoelectric cell,

Fig. 2 is an enlarged vertical section on line 2-2, Fig. 1, showing the lay in full lines in the position which it occupies while the shuttle is in flight through the warp shed and in broken lines when the lay is at front center,

Fig. 3 is an enlarged detailed end elevation looking in the direction of arrow 3, Fig. 1,

Fig. 4 is a plan view of the shuttle and bobbin therein such as may be used with the'invention,

Fig. 5 is a diagrammatic view of a form of electric circuit which can be utilized to carry the preferred form of the invention into effect,

Fig. 6 is a view similar to Fig. 2 but showing the modified form of the invention which relies upon increased illumination of the photoelectric cell,

Fig. 7 is an enlarged detail front elevation of part of the loom looking in the direction of arrow 7, Fig. 6,

Fig. 8 is a diagrammatic view similar to Fig. 5 but showing the electric circuits for the modified form of the invention, and

Fig. 9 is an enlarged horizontal section on line 9-9, Fig. 2, showing spaces forward of the reed dents and between groups of warp threads between the dents.

Referring to Fig. 1, the loom has right and left loomsides 1 and 2, respectively, which support a rocker shaft 3 for the right and

left lay'swords

4 and 5, respectively, which support the lay designated generally at 6. In the present instance the lay has a single shuttle box R at the right end thereof and a gang L of two

shuttle box cells

7 and 8 at the left end thereof. The loom in the present instance operates with two means to lay weft in a warp shed, shown herein as shuttles one of which Si is shown in the loom shuttle'box R and the other of which 3 S2 is shown at the left end of the loom in tle box cell 8.

The lay swings backwardly and forwardly in the loom is usual manner by power imparted to its from a top shaft iii through connectors one of which is shown at 11 in Pig. 2. The top shaft has a gear 12 secured thereto meshing with a gear 13 of twice its size secured to the bottom shaft 14. The latter shaft has right and left picking

arms

15 and 16 for cooperation with picking earns 17 and 18, respectively operatively connected to picker sticks P1 and P2, respectively. The picker sticks operate one at a time and usually during the backward stroke of the lay at a time when the latter is at or near its top center position, that is, approximately midway between its extreme front and back positions. Each picker stick when operating will propel the shuttle aligned with it from one end of the loom to the other end, causing it to pass through a warp shed designated generally at W, see Fig. 2, comprising upper and lower sheets, planes or groups of

weft work threads

20 and 21, respectively. These threads pass through a reed 22 the lower edge of which is positioned by the lay beam member 23 and the upper edge of which is positioned by a hand rail member 24. The latter is supported by arms 25 one of which is shown in Fig. 2 extending upwardly from the lay structure 6. The lay beam has a shuttle race 26 under the hand rail and along which theshuttles travel when in flight between shuttle box structures R and L.

At the time of picking of a shuttle the lay will be moving rearwardly, or to the right as viewed in Fig. 2, and will ordinarily reach its back center position while the shuttle is in flight and in the warp shed. The lay will then start forwardly as the shuttle continues to move through the shed. If for any reason the shuttle should be traveling slower than usual, or should be stopped in the warp shed, it is necessary to effect prompt stoppage of the loom in order to prevent the reed 22 from pushing the shuttle forwardly through the warp shed and breaking some of the warp threads. It is the general purpose of the present invention to effect this stoppage of the loom should the shuttle fail to reach a given point in its travel along the lay at a given time in the cycle of the loom.

The invention to be set forth hereinafter may operate on a bobbin changing loom having a reserve bobbin magazine M to effect replenishment of each of the two shuttles when they are substantially depleted of weft. The shuttles may both be as shown in Fig. 4, wherein shuttle S1 is particularly set forth. The shuttle has

ends

30 and 31 as shown at the right and left, respectively, of Fig. 4 and these ends will be so constructed as to be opaque to the passage of light. The end 30 may be provided with a shuttle eye 32 while the end 31 may be equipped with a spring jaw 33 to hold the head 34 of a bobbin designated generally at B. The bobbin will include a barrel 35 exthe lower shuttending to the right from the head 34 as viewed in Fig. 4

and terminating in a tip 36 which will ordinarily be closely adjacent to but spaced from the end 30 of the shuttle. The barrel 35 of the shuttle has a mass of weft 37 wound thereon which will become depleted during loom operation so as to uncover the greater part of the barrel 35. The spring jaws 33 will ordinarily hold the bobbin B so that its barrel is located substantially centrally transversely of the shuttle, as is apparent from Fig. 4.

Both of the shuttles S1 and S2 may be as set forth in Fig. 4 although the invention is not necessarily limited to use with shuttles adapted for weft replenishment, but when such shuttles are used the bobbin barrel 35 can be relied upon to effect part at least of the decreased illumination already mentioned hereinbefore. It will be understood that the shuttle will be formed with a bobbin compartment 38 which is open at its bottom to permit expulsion of a depleted bobbin as a fresh bobbin is inserted into the shuttle from above.

The matter thus far described may be constructed and operated in the usual manner.

The loom is driven by a motor 40 which as shown herein is provided with a pinion 41 meshing with a motor gear 42 fixed to the top shaft 10. The motor is of the socalled stop and start type and whenever the motor is in operation the loom will be running and whenever the motor is stopped the loom will stop with it. The motor is controlled by electrical devices which need not be described in detail herein but which are contained in'a panel or box 43, see Fig. 5, which in turn are controlled by a master relay 44. The relay controls a master switch MS, see Fig. 5, having an armature or which blade 45 and a contact 46 therefor. When the relay 44 is energized the blade 45 is in engagement with the contact 46 and

wires

47 and 48 leading from the switch MS to the panel 43 are electrically connected and maintain the condition for continued running of the motor. If the relay 44 becomes deenergized the spring 49 will open switch MS and the

wires

47 and 48 will be electrically disconnected, whereupon the equipment within the panel 43 will effect very prompt stoppage of the motor and loom. The master relay 44 and its switch, and the equipment controlled by the switch may be considered to be loom governing means controlling motor and loom operation capable of either stopping the loom or continuing its operation.

Loom stoppage may be effected by any of the known electrically operating means for this purpose, such as by a magnetic brake, or by application of a so-called plugging current which will stop the motor almost instantly. The motor 40 will ordinarily be operated by a threephase alternating current and the plugging may be effected by direct current. We do not wish to be limited to any particular means for stopping the motor and it will be sufiicient for the purposes of the invention if electric means operates to stop the motor upon deenergization of the master relay 44.

The invention operates with two switches one of which is a loom controlled timer switch designated at T5 and the other of which is a shuttle controlled switch designated at SS. The timer switch includes a contact arm 50 normally held against contact 51 by a spring 52 but moved away from the contact 51 periodically by a cam 53 having a cam point 54. The cam 53 is secured to a shaft 55 mounted for rotation in a stationary stand 56 which may be mounted on the left hand loomside 2 as viewed in Fig. 1. The stand 56 supports the arm 50 and also the contact 51. A sprocket wheel 58 secured to the top shaft 10 is connected by a chain 59 to another sprocket wheel 60 of the same size as sprocket 58 secured to the shaft 55. The cam 53 therefore completes a rotation each pick or beat of the loom and the cam point 54 will open the timer switch TS at regularly recurring intervals each pick of the loom when the shuttle should be at a given point in the path of its travel along the lay. We do not wish to be limited to the particular type of timer switch shown in Fig. 3, and it will be sufiicient if the timer switch is normally closed but opens periodically.

The master relay 44 is in a circuit including a transformer 65, wire 66, relay 44, wire 67, contact 51, arm 50, wire 68, switch LS to be described more in detail hereinafter, and wire 69 back to the transformer. The contact 51, arm 5t and part of wire 68 may be considered as one of two parallel branch circuits the other of which will be described hereinafter. During the greater part of the cycle of the loom this branch circuit will be closed and the master relay will be maintained energized by current flowing through the switch TS, but as already mentioned this circuit will be opened periodically and unless relay 44 is energized by closure of the switch SS it will become deenergized and effect loom stoppage.

In the preferred form of the invention the loom is provided with means for directing a beam 70 of light across the path of the shuttle and preferably through. the warp shed. As shown in Figs. 1 and 2, this beam of light may be provided by an illuminating element, such as an electric lamp 75, carried by a small stand 76 secured at 77 to the hand rail. The hand rail has a hole 78 therethrough below the lamp and whenever the latter is illuminated its filament 79 will direct a beam of light down. through the hole 78 from one side of the warp shed, the upper side as shown herein.

The lay beam 23 is provided with a hole 80 aligned with the hole 78, and a photoelectric cell unit or element 81 is secured to the under side of the lay beam on the other side of the warp shed, said other side as shown herein being the under side of the shed. The photoelectric cell, designated more particularly at 82 as part of unit 81, will be in the path of a beam of light originating with the filament 79 and passing downwardly through the hole 78, through the upper and

lower sheets

20 and 21 of warp threads, across the shuttle race 26, and through the hole 80 in the lay. This beam of light crosses the shuttle path and will be intercepted by a shuttle passing along the lay. When the type of shuttle already decribed is used the beamof light will be spaced forwardly from the reed 22 a distance approximately equal to the distance from the transverse center of bobbin barrel 35 to the reed, see Fig. 2, when the shuttle is against the reed.

Two

wires

85 and 86 supplying preferably direct current are connected by resistances R1, R2 and R3 which are in series as shown in Fig. 5. Adjustable tap 87 is slidable along the resistance R2 and is connected to a resistance R4 which in turn is connected to a junction point 88. An electronic tube E preferably of the high vacuum type has a cathode 90, a control grid 91, and a plate 92. The plate 92 is connected by wire 93 to a control relay 94 which controls the switch SS. The other side of the relay 94 is connected to the positively charged wire 85.

Negatively charged wire 86 is connected by resistance R5 to the cathode 90 and also to the cathode or negative element 95 of the photoelectric tube 82 which is also preferably of the vacuum type. The anode or positive element 96 of the photoelectric cell is connected by wire 97 to the junction 88.

The resistance R4 and the photoelectric cell 82 jointly control the electrical potential of the junction 88 and under normal conditions when the beam of light from the filament 79 is uninterrupted the voltage of the junction 88 will be at such electric level that the grid 91 will permit suflicient current to flow through the electronic tube E to maintain the control relay 94 energized and the latter will hold its contact or switch blade 98 away from a contact 99 as shown in full lines in Fig. 5. Switch blade 98 is connected by wire 100 to the wire 67 and contact 99 is connected by wire 101 to wire 68. Wire 100, blade 98, contact 99 and wire 101'constitute a second branch circuit in parallel with the first mentioned branch circuit. The switches TS and SS are therefore in parallel branch circuits both connected to the master relay 44.

The control relay 94 will be energized sufiiciently to maintain the shuttle switch SS open when the shuttle S1 is in the full line position in Fig. 5, but when the shuttle as it travels through the shed reaches a given point along its path where its advancing end intercepts or interrupts the beam of light a shadow will be cast on the photoelectric cell 82 to decrease its illumination and there will be a change in the electric potential of the junction 88 such as will cause the grid 91 to become more negative than it was previously and the amount of current which can flow through the tube E will be insuflicient to maintain the control relay 94 energized. The switch SS will thereupon be closed, see dotted lines in Fig. 5, and if this closure occurs at the time in the loom cycle while switch TS is open due to the fact that the shuttle is running on time the master relay 44 will remain energized and the loom will continue to run. If, however, the shuttle is running late or has not been able to intercept the beam of light when switch TS opens then both of the aforesaid parallel branches of the electric circuit of the master relay will be open and the latter will become deenergized with consequent opening of switch 45 and resultant stoppage of the motor 40 and the loom.

In the aforegoing description there has been set forth means for creating a single beam of light which will be located more or less centrally of the length of the lay, as will be apparent from Fig. 1. If, however, it should be desired to have the shuttle give indication of its presence when nearer the shuttle box toward which it is traveling two beams of light can then be used and the cam which operates the timer switch will be set to ope nswitch TS a little later in the loom cycle in a manner as set forth for instance in Patent No. 2,586,335, issued February 19, 1952 to the present inventor Sepavich and Howe. Interception of the beam of light will ordinarily occur while the lay is in a position substantially behind the position which it ordinarily occupies with the usual protector rod type of protection, and therefore more time will be allowed for stopping the loom before there is danger that a shuttle trapped in the shed will be pushed through the warp threads.

If the lamp should fail, as by burning out of the filament 79, no beam of light would fall on the photoelectric cell and the latter would be in a condition of decreased illumination and keep switch SS closed Without regard to the position of the shuttle, and the loom would be without protection. In order to guard against this contingency the previously mentioned switch LS will be under control of the lamp circuit. This switch LS has a contact 105 normally engaging an armature blade 106 because of continued energization of an electromagnet 107. The latter is in series with the lamp which derives its power from a transformer 108 as will be apparent from Fig. 5. Whenever the filament '79 burns out current will be interrupted in the electromagnet 107 and the spring 109 will then open the switch LS which, being in series with transformer 65, will immediately efiect deenergization of the master relay 44. The electromagnet 107 is shown herein as a convenient means for keeping the switch LS normally closed, but we do not wish to be limited to the use of such a magnet, and any form of control for switch LS may be used which will keep the switch closed when the filament 79 is intact but will effect opening of switch LS upon failure of the filament.

In operation it is found that the warp threads will not ordinarily cast a sufiicient shadow on the photoelectric cell to preventillumination of it at a level sufficient to maintain the:control relay 94 energized. The passage ofthe shuttle through the beam of light, except where very dense warps are used, will always effect a sufiicient change in the illumination of the photoelectric cell. to cause the desired change in the grid 91. It will be understood that when the lay reaches the position shown in broken lines in Fig. 2 the fabric F will be in the path of the beam of light and may momentarily cast a shadow on the photoelectric cell, but this occurs at a time in the loom cycle after switch TS has closed, and these is no likelihood that the shadow cast by the fabric can interfere with the operations already described.

In the modified form of the invention, an example of which is illustrated in Figs. 6 to 8, the photoelectric cell depends upon an increase in its illumination by the shuttle at the aforesaid given time to permit continued running of the loom. In this form of the invention much of the matter thus far described will be used, but instead of the shuttle casting a shadow on the photoelectric cell the shuttle is so made that it will reflect a beam of light onto the photoelectric cell to increase the amount of light falling on it.

Fig. 6 shows a lay beam 115, a hand rail 116, and a reed 117 along which a shuttle S3 travels when laying weft in the warp shed W. The hand rail has mounted thereon a source of illumination or lamp element 120 which may be held in position with respect to the hand rail by a bracket 121 secured to the hand rail at 122.

7. Hand rails customarily employ some form of shuttle. guard which is indicated. herein at 123 and this: guard may be utilized to assist insupportingxthe, bracket 111 as shown in Fig. 6, or may if desired be the sole support for the lamp element.

The shuttle S3 has the front wall. thereof provided with a reflector 125 on which light from thelamp element 120 can fall. Secured to the forward part of the lay beam 115 is a photoelectric cell unit 126 held in. position on the lay by a bracket 127. The bracket is provided with a hood 128 which opens upwardly and rearwardly toward the shuttle path and prevents direct illumination of the cell element by the lamp element.

As is apparent from Fig. 7 the lamp element and photoelectric cell element are arranged one above the other and preferably in such relation that the beam of light, shown at 130, will travel downwardly and rearwardly through the top sheet 20 betweenv the threads thereof against the reflector 125 and from the latter downwardly and forwardly through the bottom warp. sheet 21. The arrangement set forth more particularly in Fig. 6- is set forth as an example and we do not wish necessarily to be limited to the particular location of the reflector on a shuttle or the disposition of the lamp and photoelectric cell elements. It will be suificient for the purposes of the modified form of the invention it passage of the shuttle is the means by which light originating with the lamp element can be caused to illuminate the photoelectric cell element.

Under normal conditions the lamp, which may be similar to the lamp described in connection with the preferred form of the invention, directs a. beam of light through the top warp sheet 20 and when the shuttle in its passage along the lay enters the beam of light the reflector 125 will deflect the beam of light downwardly and forwardly through the hood or shield 128 on to the cell 126. If the shuttle is on time in its flight it will reflect the beam of light to increase the illumination of. the photoelectric cell at the correct time in the cycle of the loom, but if the shuttle is late, or for any other reason fails to enter the beam of light at the correct time, the illumination of the photoelectric cell will not be increased and the loom will be stopped A large part of the electric circuits usedwith the modified form of the invention will be similar to that already described for the preferred from of the invention, but when a photoelectric cell actsdue to' increase in its illumination it is necessary to make some changes in its electric connections, as indicated in Fig. 8 which is similar to Fig. except for these changes and the control for the switch of the branch circuit which is controlled by the photoelectric cell.

In the modified form of the invention the photoelectric cell 126 has its anode 131 connected by wire 132 to the previously described positively charged wire 85, and its cathode 133 connected by wire 134- to junction 88. A relay 135 corresponding to previously described relay 94 electromagnetically controls a switch blade 135 which is normally spaced from a contact 137 throughout the greater part of the loom cycle. Whenever relay 135 is energized it attracts the armature balde 136- and moves it against contact 137, and upon deenergization of the relay 135 a spring 138 returns the blade 136 to its normal noncontacting position.

In the operation of the modified form the photoelectric cell 126 will not be illuminated except briefly at periodic intervals, and because of this fact the junction 88 is normally at a relatively low potential and maintains the grid 91 in such electric condition that insufficient current can flow through the electronic tube to energize relay 135. When the shuttle reflects the beam of light 13!) toward the cell 126 the latter is able to conduct more current and has the efiect of raising the potential of the junction 88, whereupon the grid 91 is made less negative and enough current can. pass through the: electronic tube to. energize the relay and. cause the latter to effect engagement between the. blade 136 and contact 137..

and the master relay will remain energized; I-f,.however, the. energi'zation of. the relay 135. does not occur, due to a late orslowrunning shuttle, until after the timer switch is open, the master relay will then become deenergized. and. the loom will he stopped as already described.

No matter how dense thev warp may be with regard to either its opacity or number of threads to the inch each reed. dent will separate the threads of both the top and bottom warp sheets at: the sides of it into groups between which there. will be a. space in front of the dent, and the source of light: and. photoelectric cell can be so located that the. beam of light can register with and be directed through one or more ofthe. spaces forward of the reed dents. Thus, in Fig. 9 separate den-ts of reed. 22. are designated at 140 and. the spaces between groups 141 of wrap. threads are shown at 142. These spaces are triangular shaped. and extend forwardly from the dents to the fabric F. If the beam of light 70, for instance, is aligned with a. space 1422 as shown in Fig. 9 enough light will get through both sheets of the warp for proper illumination of the photoelectric cell. The beam of light may in fact be wide enough to. pass through two or more of the spaces 1142 if the reed is of fine gauge.

From the foregoing; it will be seen that the invention sets forth simple meansaby which operation of a loom is controlled byelectric means including a photoelectric cell which due to a change in its illumination will permit the loom to continue running it the change occurs at a given time in the loom cycle. The change in illumination of the cell is eitectedby the shuttle, and this change may be a decrease in the: illumination of the cell if the preferred form of the invention is used wherein the shuttle casts a shadow, or the change may be due to an increase in illumination-of the cell it the modified form of the invention is used wherein the reflector 125 on the shuttle momentarily deflects light. onto the photoelectric cell.

In both forms of the invention the beam of light will pass through the Warp shed when it is desired that the shuttle give an indication comparatively early in its travel. Although a single beam of. light has been shown two beams can be spaced along the length of the lay on opposite sides of the beam shown for instance in Fig. l and the timer switch can then. be set a little later. In the preferred form of the. invention failure. of the lamp would create the condition of decreased illumination and in order to prevent continued loom operation under these conditions the switch LS is provided which is dependent for its closure upon flow of current, through the lamp. In the modified form of the invention the switch LS is not necessary, since burning out ofrthe lamp filament would prevent an increase in the illumination of the photoelectric cell and the loom would be promptly stopped. In the preferred form of the invention, particularly when the shuttle can be utilized to interrupt the beam of light. While the lamp has been shown as being supported by the hand rail and the cell by the lay beam, these two elements can or" course be interchanged with respect to the hand rail and lay beam members. The invention also sets forth novel .lay structures carrying lamp and photoelectric cell elements, the lay for the preferred form of the invention having these elements directly in line so that the beam of light passes from one to the other, while the lay for the modified form of the invention has at least one of the elements hooded or shielded so that the cell element cannot be excited by direct light derived from the lamp element. The switches TS and SS and the photoelectric cells, together with their electric connections, may be considered as control means for the loom governing means, the latter including the master relay 44 and its connections to thepanel 43. Also, the beam of light can This: engagement. will occur when the timer switch 'is open if the: shuttle is running on. time.

be in register with one or more of the reed dents to pass through one or more of the spaces 142 forward of the reed.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In protection means for a loom dependent for continued operation upon closure of electric circuit means and a regularly recurring decrease in the illumination of a photoelectric cell, electric means including a lamp filament to illuminate said photoelectric cell, an electric switch in series in said electric circuit means, and means dependent upon flow of electric current through said filament to effect closure of said switch and effective to open said switch upon failure of electric current to flow through said filament.

2. In protection means for a loom having a ward shed and providing a path for a shuttle in flight, a source of light on one side of the shed causing a beam of light to be directed toward said path, a photoelectric cell on the opposite side of the shed out of said beam of light, electric loom controlling means including the photoelectric cell effective upon an increase in the illumination thereof at a given time in the cycle of the loom to continue loom operation and effective upon failure of an increase in the illumination at said time to stop loom operation, and a shuttle effective when reaching a given point in the flight thereof to cooperate with said source to cause an increase in the illumination of said photoelectric cell.

3. In a lay and shuttle for a loom, a light source element on the lay, a photoelectric cell element on the lay, means on the lay preventing direct illumination of the cell element by the source element, and a shuttle having a reflector thereon effective when located at a given point along the lay to reflect light from said source element onto said cell element.

4. In a loom, a light source element, a photoelectric cell element, means preventing direct illumination of the cell element by the source element, a shuttle comprising a reflector effective when the shuttle is in flight to reflect light from the source element onto the cell element to increase the illumination of said cell element, and means effective to stop the loom upon failure of the reflector to effect a change in the illumination of said cell element at a given time in the cycle of the loom.

5. In protection means for a loom having a shuttle which when running properly passes a given point in its path at a given time in the loom cycle, means to create a beam of light at said point, a photoelectric cell normally out of the path of said beam of light, a reflector on the shuttle elfective when the shuttle is at said point to reflect said beam of light onto the photoelectric cell to increase the illumination of the latter, and loom controlling means controlled by the photoelectric cell effective to cause continued loom operation upon an increase of illumination of said photoelectric cell at said time and effective to stop the loom upon failure of said photoelectric cell to have the illumination thereof increased at said time.

6. In protection means for a loom providing a path for a shuttle in flight, a source of light, a photoelectric cell forward of said path, electric loom controlling means including said photoelectric cell effective upon an increase in the illumination thereof at a given time in the cycle of the loom to continue loom operation and effective upon failure of an increase in the illumination of the photoelectric cell at said time to stop loom operation, and means causing the shuttle when reaching a given point in the flight thereof to cooperate with said source to cause an increase in the illumination of said photoelectric cell.

7. The protection means set forth in claim 6 wherein the source of light directs a beam of light to one side of the photoelectric cell and the shuttle when reaching said given point directs the beam of light toward the cell.

References Cited in the file of this patent UNITED STATES PATENTS 2,026,147 Turner Dec. 31, 1935 2,279,675 Gutman Apr. 14, 1942' 2,670,014 Hutchison Feb. 23, 1954