US2951510A

US2951510A - Ribbon loom with automatic detection of weft thread exhaustion and possible automatic replacement of the filling bobbin

Info

Publication number: US2951510A
Application number: US686304A
Authority: US
Inventors: Redaelli Edoardo
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-09-26
Filing date: 1957-09-26
Publication date: 1960-09-06
Anticipated expiration: 1977-09-06

Description

Sept. 6, 1960 E. REDAELLI 2,951,

RIBBON LOOM WITH AUTOMATIC DETECTION OF WEFT THREAD EXHAUSTION AND POSSIBLE AUTOMATIC REPLACEMENT OF THE FILLING BOBBIN Filed Sept. 26, 1957 7 Sheets-Sheet 1 Sept. 6, 1950 E. REDAELLI 2,951,

RIBBON LOOM wITH AUTOMATIC DETECTION OF WEFT THREAD EXHAUSTION AND POSSIBLE AUTOMATIC REPLACEMENT OF THE FILLING BOBBIN Filed Sept. 26, 1957 7 Sheets-Sheet 2 2,951,510 EAD EXHAUSTION LING BOBBIN 7 Sheets-Sheet 3 Sept. 6, 1960 RIBBON LOOM WITH EDOARDO REDAELLI Sept. 6, 1960 E. REDAELLI 2,951,510

ON WEFT THREAD EXHAUSTION \IIATIC REPLAC JENT THE FILLING BOBBIN 7 "heets-Sheet 4 RIBBON LOOM WITH AUTOMATIC DETE UTO! AND POSSIBLE A Filed Sept. 26, 1957 IN VEN TOR.

EDOARDO REDAELLI Sept. 6, 1960 E. REDAELLI 2,951,510

RIBBON LOOM WITH AUTOMATIC DETECTION OF WEFT THREAD EXHAUSTION AND POSSIBLE AUTOMATIC REPLACEMENT 0 Filed Sept. 26, 1957 v THE FILLING BOBBIN '7 Sheets-Sheet 5 p 1950 E. REDAELLI 2, 51,510

RIBBON LOOM WITH AUTOMATIC DETECTION OF WEFT THREAD EXHAUSTION AND POSSIBLE AUTOMATIC REPLACEMENT OF THE FILLING BOBBIN Filed Sept. 26, 1957 7 Sheets-Sheet 6 R w W W.

EDOARDO REDAELLI I hawp 6, 1960 REDAELLI 2,951,510

RIBBON LOOM WITH AUTOMA DETECTION OF WEFT THREAD EXHAUSTION AND POSSIBLE AUTOMATIC REPLACEMENT OF THE FILLING BOBBIN Filed Sept. 26, 1957 7 Sheets-Sheet '7 FIG. 5B

INVENTOR. EDOARDO REDAELLI RIBBON .LOOM WITH AUTOMATIC DETECTION OF WEFT THREAD EXHAUSTION AND POSSI- BLE AUTOMATIC REPLACEMENT OF THE FILL- ING BOBBIN Edoardo Redaelli, Via Grasselli 4, Milan, Italy Filed Sept. 26, 1957, Ser. No. 686,304

11 Claims. (Cl. 139-243) Ribbon looms are not suited for being provided with devices for the automatic replacement of the filling bobbin as are looms for weaving fabrics of greater width, because those devices would not be compatible with the reduced dimensions, with the lightness, and with the rapidity and kind of movements of the members of a conventional ribbon loom.

As is obvious, the replacement of the filling bobbin must be carried out at a time when the shuttle is at rest. Now with common ribbon looms the periods of standstill of the shuttle with respect to the loom-frame are always very short because the shuttle passes alternately from a period during which it moves transversely with respect to the Warp, to a period during which it moves in unison with the sley box, so that intermediate periods of total immobility are lacking in practice.

In order to make the detection of the weft-thread exhaustion and, if needed, also the replacement of the filling bobbin possible and convenient practically in ribbon looms automatically, according to the present invention the shuttle is cleared from the movement of the reed and provided with an alternate movement transversely to the warp only in such a manner as to keep the shuttle completely motionless during every beat-up period of the reed, so as to have sufficient time available for carrying out the detection of the weft-thread exhaustion and preferably also the replacement of the filling bobbin without any need for rapid pulses or violent stresses. Of course the means for carrying out the replacement of the filling bobbin is actuated by a member adapted to reveal the forthcoming thread exhaustion, so as to make sure of intervening prior to actual exhaustion of the thread. This member may also be conveniently used to cause the stopping of the loom in lieu of bobbin replacement, in order to avoid, at least, the greater losses of time required remedying the defects in operation which may be caused by the running of loom with one or more exhausted filling bobbins.

One practical embodiment of a loom built according to the invention is illustrated diagrammatically in its essential parts in the accompanying drawings wherein:

Fig. 1 is aside view;

Fig. 2 is a plan view;

Fig. 3 is a perspective View of the loom with certain parts thereof omitted for the sake of clarity of illustration;

Figs. 3A and 3B are fragmentary perspective views of the loom with certain parts omitted for the stake of clarity of illustration to show the operation of the bobbin.

changing mechanism of the loom, the mechanism being shown in Fig. 3A in the position it assumes just prior to the exhaustion of the weft threads on the filling bobbin, and in Fig. 33 after the filling bobbin has been exhausted;

Fig. 4 is a fragmentary view, partly in section of the shuttle containing an empty filling bobbin and drawn on a larger scale than that of Figs. 1 and 2;

Fig. 5 is a fragmentary perspective view illustrating an alternative construction of the bobbin replacement mechanism of the loom, the figure showing the shuttle and the feeder with the feeder in its lowermost position;

Figs. 5A and 5B are fragmentary perspective views of this modified mechanism showing, respectively, the feeder in inoperative and in operative positions;

Figs. 6, 7 and 8 are respectively a front elevation, cross-section, and plane view of the shuttle of Fig. 5, and showing a filling bobbin in position in the shuttle; and

Fig. 9 is an end view of the parts appearing in Figs. 6, 7 andS.

On the loom-frame 1 there is supported by means of brackets 2, a main shaft 3 driven by any convenient transmission 4. At the end of the shaft 3 there are fixed two eccentrics 5 provided each with a circular groove 6 and having an eccentricity almost equal to their radius. In each groove 6 there is accommodated a pin 7 carried by a horizontal rod 8 supported by two parallel connecting rods 9 fulcrumed at 10 on the lower portion of the frame 1. Owing to the marked eccentricity of the aforesaid groove 6, the rotation of the eccentrics 5 causes a reciprocating motion of the rods 8 which has almost zero speed over about half of a revolution of the shaft 3 and a comparatively elevated speed during the remaining half revolution, in both directions.

The two rods 8 each carry an upward extension indicated at 11, which supports at its respective end a traverse bar 12. The traverse bar carries the reed 14 by means of the arms 13.

On the main shaft 3 there is fitted a toothed pinion 15 which meshes with a rim of a toothed wheel 16 fitted onto the shaft 17 rotatable on supports rigid with the frame 1. The ratio of transmission between the pinion 15 and the toothed wheel 16 is one to two. Hence the speed of revolution of the shaft 17 is half the speed of shaft 3. On the shaft 17 there is fitted a drum 18, in

the peripheral surface whereof there is provided a groove 19 wherein there is accomodated a small roller 20 pivoted on a lever 21 fulcrumed at 22 on a lower traverse bar 23 of the frame 1. The shape of the groove 19 is such as to impart to the lever 21, by means of the small roller 20, an oscillatory movement about the fulcrum 22 in a plane parallel to the shaft 17 with a certain stopping period in each of the two extreme positions of said oscillatory movement. The drum 18 is fitted onto the shaft 17 in such a manner that the groove 19 causes the periods of stopping of the lever 21 while the rods 8 carrying the traverse bar 12 and the reed 14 perform their stroke which, as said above, takes place during half revolution of the eccentric 5.

The upper end of the lever 21 carries a ring 24 through which there passes a shaft 25 which can freely turn therein but cannot displace axially with respect to it, being ported by the

brackets

27 and 28 rigid with the frame 1.

a 3 Over a section of its length 29, the shaft 25 is of square cross-section and, consequently, the bore of the support 28 within which the shaft 25 can slide axially, is square in cross-section. The bore of the bracket 27 is round in cross-section. The cross-section of the portion of the shaft 25 which is supported by bracket 21 and through which said portion is slidable axially is also round. Section 29 of the shaft 25 is twisted helically through an angle of 90, with the efiect that since this part passes through the bore of the bracket 28 of the shaft 25, being moved axially by action of the lever 21 by means of the ring 24 mentioned above. It rotates about its axis through an angle of 90 in one direction or in the other direction.

On the shaft 25 there are fixed two

sectors

30 and 31 adapted to engage at their peripheries in arcuate grooves 32 formed with the underside of the shuttle 33. The latter is supported slidably by two

aligned guides

34 and 35, which are spaced from each other by a distance sufficient to allow the movement of the warp threads but smaller than the length of the shuttle. Thus, the shuttle is constantly supported by at least one of the two aforesaid guides.

The warp is indicated in Figure l by the reference numeral 36 and is controlled to move in the customary way by the healds 37 which are actuated to move by a mechanism controlled by the shaft 3. That mechanism is of a kind usually known in looms and, therefore, it is not represented in the drawings for the sake of simplicity and clearness.

The loom with its members as described hereinbefore, operates as follows.

Starting from the position indicated in the drawings, the revolution of the shaft 3, and, therefore, of the eccentric 5, causes a movement towards the left of the reed 14, through the

members

6, 7, 8, 11, 12 and 13; and the reed thus is brought between the guides 34-35 of the shuttle and the healds 37. During this stage, the gear 15 fitted onto the shaft 3 has rotated, through the gear 16, the shaft 17 and the drum 18 carried thereby, but the groove 19 owing to its shape as outlined above, has not caused any movement of the lever 21.

During the subsequent half revolution of the shaft 3, the groove 6 of the eccentric which, as has been said, passes in correspondence or in proximity of the axis of the shaft 3, does not impart any movement to the reed 14 or imparts to it only a movement negligible in practice. Meanwhile however an inclined section of the groove 19 of the drum 13 engages the small roller 26 and makes the lever 21 accomplish a stroke which through the ring 24 displaces the shaft 25 downwardiy as viewed in Fig. 2. Through the sector 31, now engaged in the respective arcuate groove 32 of the shuttle 33, the shaft 25 displaces the said shuttle towards the left in Pig. 3 (It should be noted that in Fig. 3 the lever 21 and the end of the shaft 25 controlled by it, are not represented for the sake of simplicity) thereby making the shuttle leave the guide 35 and enter the guide 34. Meantime the section 29, having square cross-section and helical shape, of the shaft 25 causes said shaft as well as the

sectors

36 and 31 to rotate, thereby making the latter leave the respective groove 32 of the shuttle, and the sector 30 enter the other groove so that the sector ,36 can drive the shuttle during the last portion of its stroke after release of the shuttle from sector 31.

On termination of that stage, the small roller 20 is in a section of the groove 19 which causes no movement, while at the same time the groove 6 of the eccentric 5, which now engages the small roller 7 at points farther and farther from the axis of the shaft 3, causes another to and fro movement of the rod 8 and, therefore, of the reed 14, which performs its beat while the shuttle is at standstill in its guide 34, and returns again towards the healds 37.

Subsequently the movements are repeated reversely as for the shuttle and members controlling it, a subsequent beat of the reed 14 being then repeated and the cycle being thus accomplished, which then is repeated in identical manner.

The automatic replacement of the filling bobbin takes place by operation of the members which will be described hereinafter.

The feeder of the replacement filling bobbin is constituted by a carrier head 38 pivoted at 39 on the body of the slide 34. It retains the filling bobbin 40 by means of two resiliently actuated jaws 41 and of a front projection 42 with a slot 43 adapted to engage between the resilient arms 44- of the shuttle 33 to enable inserting of the thread.

The filling bobbin is represented diagrammatically in Fig. 4. It forms the subject of another patent application of the same date and of same applicant and is composed of two parts 45-46 which are telescopically mounted on a pin 47 and urged towards their extended position by an internal spring 48. The filling bobbin is loaded with thread with its parts 4546 retracted against the reaction of the spring 48, so that the thread tends to retain said parts in retracted position. When the thread wound on the bobbin is going to become exhausted, its few windings are no longer suflicient to retain the parts 4546 in retracted position. Hence the bobbin becomes elongated owing to the prevailing of the force exerted by the spring 48.

An improved kind of filling bobbin is formed of two parts 45-46 slidable telescopically relative to each other but prevented from turning with respect to each other by a groove on one part cooperating with a small tooth on the other. This has the purpose of preventing a rotation 'of one part with respect to the other one, such as might be caused by the traction of the thread when at its last few windings, causing an undesirable arrangement of the thread on the filling bobbin.

By means of an arm 49 and a link 50, the feeder 38 is connected to the arm 51 of a piece 52 which is supported rotatably and slidably by a spindle 53 fixed and rigid to the loom-frame. The piece 52 is also provided with an arm 54 shaped as is seen in Fig. 3 and having sucha thickness dimensions that it can be received in a notch 55 of an extension 56 fixed to the traverse bar 12. On the piece 52 there is provided a throat 57.

On the support 27 there is pivoted at 58 (Fig. 1) a small lever 59 connected at a point 60 of the sleeve 21. This lever 59, which is made to oscillate by the lever 21, imparts a simultaneous reciprocating movement to a spindle 61 supported slidably by supports, not shown. This spindle thus follows in a reduced scale the movements of the shuttle.

On the spindle 61 there is pivoted at 62 a lever 63 one end of which is housed in the aforesaid throat 57 of the piece 52.

On the shaft 17 there is mounted, in addition to the drum 18, a cam 64 which transmits a reciprocating rectilinear movement, by means of the rod 65, to a deformable element composed of a sheath 66 and of a blade 67 contained therein, and projecting at its top from said sheath, and terminating in a fork 68. The

parts

66 and 67 are coupled with each other by a spring 69 anchored at one end to the blade 67 and at its other end to a'pawl 70 pivoted at 71 on the sheath 66 and adapted to penetrate into a notch 72 provided in said sheath 66 when a corresponding notch provided in the blade 67 is in a position or register with the notch 72. This occurs in the lowermost position of the blade 67 with respect to the sheath 66. Moreover, the sheath 66 is provided with a notch 73 which, if the blade 67 finds itself in the aforesaid lowermost position, is blocked by a section of said blade itself, While if the blade 67 finds itself in its uppermost position with respect to the blade 66, a corresponding notch of the blade 67 becomes aligned with the aforesaid notch In this latter position, the lever 63 can pass through the notch 73 during the reciprocating movement of the lever produced by the spindle 61, so that the lever 63 is made to oscillate on the spindle 61 by pivoting in the groove 57 of the piece 52, there being freedom of rotation at 62 be tween the lever 63 and the spindle 61.

When the loom is in operation, the cam 64, through the rod 65, periodically lifts the deformable element 6667. This lifting movement takes place in the operating stage when the shuttle 33 is at rest in its guide 35. Every time this deformable element rises While the bobbin is loaded with thread and in its retracted position, the fork 68 finds the pin 47 in its way. The pin 47 can be contained in the gap between the arms of the fork and, therefore, does not prevent the vertical reciprocating movement of the latter. As a consequence, the deformable element 66-67 can descend again without undergoing deformation. When, on the contrary, the spool is exhausted, so that the thread does not keep it in retracted condition, the spool expands as indicated in Fig. 4 and the fork 68 engages the spool proper which hinders further rise of the fork. The rising movement of the sheath 66, however, continues and this causes the tip of the pawl 70 to enter the notch 72 which at that moment registers with the notch of the blade 67. Blade 67 is thus stopped in a position below the sheath 66. In this position the notch 73 is obstructed, so that the lever 63 meets a hindrance to its free oscillation during the stroke of the shuttle and the movement of the shaft 61. As a consequence, the lever 63, bearing on the part of the blade 67 which obstructs the notch 73, urges the piece 52 toward the left in Fig. 3. At this moment the traverse bar 12 is displaced so as to hold the reed between the shuttle guides and the healds. As a consequence of the aforesaid movement of the piece 52, the arm 54 penetrates into the notch 55 of the piece 56. During the return stroke of the traverse bar 12, causing the reed to perform its heat, such engagement between the piece 56 and the arm 54 forces the latter, due to its shape, to rotate by a certain angle on the fixed shaft 53. The consequent rotation of the piece 52 and the arm 51, through the tie rod 50, causes the feeder 38 to lower so as to introduce a fresh spool or bobbin into the shuttle 33 which is now in the guide 34. The edges of the projection 42 of the feeder engaged against the arms 44 (Fig. 3), thereby separating them at their tips. This causes the thread of the fresh spool, the end of which has been previously anchored to any suitable fixed point of the loom frame, to be inserted between the tips of the resilient arms 44.

During the subsequent movement in opposite direction of the spindle 61, the end of the lever 63 strikes against the stop 74, causing the lever 63 to bring the piece 52 into its previous position. During the subsequent upward movement of the deformable member 66-67, the tail 75 of the pawl 70 strikes, for a very short time, at the peak of the upward movement of the deformable element against the piece 76 which causes the disengagement of the pawl from the notch 72 and the liberation of the blade 67 which rises again into its previous position under the action of the spring 69.

With the piece 52 there may be connected any element adapted to control the stopping of the loom in any known manner, which needs no particular illustration. In that case, the means for the automatic change of the filling bobbin may even be dispensed with.

By virtue of the absolute stopping of the shuttle, the loom hereinabove described permits also of providing means adapted to feel the weft in order to detect its absence or breakage, and to stop the loom in event of such an occurrence.

One of the possible embodiments is shown in the drawings and is constituted by the members hereinafter described. The mechanism is composed of a small rod 77 supported, in such a manner that it can slide and turn,

in the supports 78 fixed to an arm 79 rigid with the loomframe. The small rod 77 is terminated, at one end, by a fork-shaped bent-in member 80 and is connected at its other end-again in such a Way that it can turn-to any conventional device 81 which serves to stop the motion of the loom.

In a convenient position, rigid with the small rod 77, there are two tongues 82-83 which in addition to the functions described hereinafter, tend to make the small rod rotate by their weight. Between one of the supports 78 and the small plate 82 there is inserted a spring 84 which presses the small rod 77 against the device 81, which results in the most suitable position for operation of the loom.

On the element 13, carrying the reed, there is fixed a small block 85, which at the end of the stroke of the reed towards the healds, can strike against the tongue 82, if the latter is lowered. Under the tongue 83 there presses a rod 86 slidable in a fixed support 87. The other end of the rod 86 rests on the the end of a lever 88 pivoted in the fixed support 89, and controlled by the cam 64, the same that controls the movement of the detecting element 66-67.

Operation of the device is as follows.

The rod 86 supports the tongue 83, keeping the fork 80 of the small rod 77 in such a position to receive the weft thread 90 carried by the shuttle which reaches its stopping point on the guide 35.

When the shuttle has arrived at its end-of-stroke position towards the right, due to rotation of the cam 64 the lever 88 will have risen lowering the rod 86, which deprives the tongue 83 of its support.

Owing to the weight of the

tongue

82 and 83, the small rod 77 rotates about its axis; and the two branches of itsfork-shaped end 80 come to rest on the thread, one above and the other one below, so that the rotation of the small rod is interrupted by the resistance of the thread.

If thread should be lacking, the rotation of the small rod 77 would continue and the tongie 821 would come to rest on the small block 85 which at that time is going towards the right. Since the reed is performing the beat; when the reed returns towards the healds, the small block 85 strikes against the tongue 82 and by overcoming the resistance of the spring 84, drags along with it the small rod 77, releasing the device 81 for stopping the loom.

Figures 5 to 9 show one improved embodiment of the shuttle feeder, wherewith the shuttle is enabled to receive the introduction of the new filling bobbin replacing the exhausted one, in a very short time (shorter than one tenth of one second). It also ensures that the thread of the new filling bobbin, upon being introduced into the shuttle, will be gripped very quickly by a brake adjustable with great accuracy to obtain perfect formation of the ribbon borders.

This shuttle comprises a body 101 shaped in such a Way as to be able to slide in the guides 34-'35 and provided with guides 102 for engaging with the two

sectors

30 and 31 and with resilient clamps 103 for clamping the pin of the filling bobbin at the two ends thereof. The body 101 has an arm 104 which extends in front of the filling bobbin at the end whereof there is pivoted at 105 a piece of approximately semi-circular shape 106, which can oscillate on the arm 104 through an angle limited by the peg 107 that strikes the arm 104 at two points. Moreover, the arm 104 is provided with a peg 108 arranged on the lower face of the am 104 perpendicular to the pin 105.

At the other end of the body 101 there is hinged at 109 an arm 110, which is provided with a tail 111 with a slot 112 wherein there acts the end of the lever 113 fulcrumed at 114 in the body 101. The lever 113 is pushed by the spring 115, the pressure of which is adjustable by means of the screw 116 screwing into the threaded bushing fixed on the body 101 and containing also the spring The end of the arm 110 carries a peg 118-, similar to the peg 108, and placed at the opposite side of a vertical plane passing through the pin 105.

At 119 there is indicated a brake for the filling bobbin 120, the thread 121 of which passes between the two

pegs

108 and 118 and is pressed between the upper face of the arm 110 and the plane lower face of the piece 106.

The pressure with which the thread 121 is pressed and braked between these two surfaces is the same whether it is in contact with peg 168 or peg 1.13, and is greater, instead, if it is located under the central portion of the oscillating piece 1%. The difference of pressure between one case and the other, however, is not very great, as can be understand from Fig. 6; and the thread can move between the two

pegs

108 and 118 while remaining always braked.

The feeder 38' is similar to the one already described. It retains the filling bobbin by means of spring urged jaws 41' and retains the endof a thread by means of the slot 43 provided in the extension 42 In the variant described, on the extension 4- there is pivoted at 122 a lever 123 carrying at its end a small roller 124, and having a nose 125. A peg 126 fixed on the extension 4-2 acts as a stop for the lever 123.

When the feeder is lifted to rest position analogous to the one shown in Fig. 3, the lever 123 remains lowered by gravity and its nose 125 retains the thread within the slot 43.

When the feeder lowers to carry out the interchange of the filling bobbin in the shuttle, the small roller 124 strikes against the arm 110 and the lever 123- goes first into the position seen in Fig. 5 opening the slot and subsequently, when the lever 123 is stopped by the stop 126, the small roller 124 causes the lowering of the arm 110.

The feeder in its descent then ejects the filling bobbin contained in the shuttle and introduces thereinto the new filling bobbin. The thread passing through the slot 43' overrides the oscillating piece 106 and when the feeder rises again, while the new filling bobbin is held in the clamps 103 of the shuttle, the thread is gripped between the piece 106 and the arm 111 as is seen in Figures 6, 7, and 8.

All the movements described above take place at the time when the reed performs the beat, whereafter the shuttle with the new filling bobbin starts again in its normal stage and the new thread is inserted in the warp, t-hus continuing the weaving of the ribbon without leaving behind any irregularity or mark in the finished ribbon.

During weaving, the thread 121 is pulled alternately towards the right and towards the left, and at the beginning of every feeding of the weft the thread runs between the two

pegs

108 and 118; and in the two positions of the thread against each of these pegs the braking action is equal. Hence the insertion of the weft takes place with perfect uniformity in both senses.

As has been said, the braking is less vigorous at the beginning of the sliding of the thread between braking surfaces, when every brake tends to give a hard pull, while the braking becomes more vigorous immediately afterwards.

I claim: V

1. A ribbon loom comprising a reciprocable reed, stationary guide means, a shuttle slidable in said guide means and adapted to hold a bobbin, said shuttle comprising a first arm and a second arm, means resiliently urging said first arm against said second arm to clamp between them thread running from the bobbin, a clamping member pivotallytmounted on said second arm to oscillate freely relative thereto, said clamping member having a surface which. rests on .a complementary surface onthe first arm, said two surfaces constituting the jaws of a friction brake for the thread of the bobbimmeans for imparting intermittent reciprocation to said reed to effect beat and return movements thereof, means for intermittently moving said shuttle in opposite directions in said guide means in time with said reed reciprocating means so that said shuttle is stationary during reciprocation of the reed, a bobbin feeder adapted to hold a reserve bobbin, detecting means for detecting the approach of thread exhaustion of the bobbin that is mounted in said shuttle, means operative during the periods when said shuttle is stationary to move said detecting means to sensing position, means operatively connecting said feeder to said detectingmeans and operative, when said detecting means detects approaching exhaustion of the thread on the bobbinthat is mounted in said shuttle, to cause said feeder to move towards and into operative relation with said shuttle, and means connected to said feeder for moving said first arm away from said second arm when said feeder has been moved to operative position, to insert the reserve bobbin in the shuttle.

2. A ribbon loom according to claim 1 wherein a stop is mounted on each of said arms, and said stops are spaced from one another a predetermined distance to limit the sliding of the thread between said arms.

3. A ribbon loom according to claim 1 having spring means constantly urging said first arm toward said second arm and saidclamping member, and means for adjusting said spring means to vary the force of said spring means.

4. A ribbon loom according to claim 1 wherein said clamping member is substantially semi-circular with its diametral surface constituting its operative clamping surface.

5. A loom according to claim 1 wherein there is a member oscillatably mounted on the feeder which retains the thread of the reserve bobbin, and which is so disposed on the feeder that upon movement of the feeder to operative position said oscillatable member engages said first arm so that it is displaced to release the thread of the reserve bobbin while moving the first arm'away from the second arm to release the thread of the bobbin which was mounted in the shuttle.

6. A ribbon loom according to claim 1 wherein the shuttle guide means comprises a pair of guides which are aligned with one another but spaced from one another a distance less than the length of the shuttle, and wherein the means for reciprocating said shuttle comprises two sectors operatively connected to said shuttle to move parallel thereto, said sectors being angularly displaced from one another, means for oscillating said sectors in unison to engage them successively with said shuttle and to move them into and out of engagement with said shuttle, and means for reciprocating said sectors in unison to impart reciprocating movement to said sectors.

7. A ribbon loom comprising a reciprocable reed, stationary guide means, a shuttle slidable in said guide means and adapted to hold a bobbin, means for imparting intermittent reciprocation to said reed, means for intermittently moving said shuttle in said guide means in time with said reed reciprocating means so that said shuttle is stationary during reciprocation of the reed, detecting means for detecting the approach of thread exhaustion of the bobbin, and means for moving said detecting means to operative position when the shuttle is stationary.

8. A ribbon loom as claimed in claim 7 having means operatively connected to said detecting means to stop the loom upon approaching exhaustion of the bobbin in the shuttle. V

9. A ribbon loom as claimed in claim 7 wherein the bobbin comprises two parts, resilient means constantly urging said two parts away from one another, said parts being adapted to be held together against the resistance of said resilient means by thread wound on the bobbin as long as there is a predetermined amount of thread on the bobbin, and wherein said detecting means comprises a reciprocable feeler, and the bobbin has a,sur-

face which is normally out of the path of reciprocation of said feeler, but which is moved by said resilient means 9 into the path of said feeler when the thread on the bobbin is approaching exhaustion.

10. A ribbon loom as claimed in claim 7, having means for replacing an exhausted bobbin, comprising a reciprocable feeder adapted to hold a replacement bobbin, and means for moving said fecder to operative position relative to said shuttle to substitute the replacement bobbin for the bobbin in the shuttle when said shuttle is stationary and said detecting means detects approaching exhaustion of the bobbin in the shuttle.

11. A ribbon loom as claimed in claim 10 wherein said feeder is oscillatably mounted on said guide means, and means is provided on said feeder for inserting the re- References Cited in the file of this patent UNITED STATES PATENTS 1,514,951 Chevrette Nov. 11, 1924 1,631,828 Lucas June 7, 1927 2,579,491 Griefen et a1. Dec. 25, 1951 2,648,355 Mostertz Aug. 11, 1953