Method and Apparatus for Transporting a Group of Yarn Packages

The invention relates to a method and apparatus for transporting a group of yarn packages between successive stages of yarn processing.

A method and an apparatus for transporting yarn packages, such as bobbins of textile yarn, from a yarn package forming machine, such as a draw-twisting machine, are disclosed in Japanese Patent Publications Nos. 12859/74 and 24812/74. This disclosed technique utilizes a long, narrow plate-shaped tray which has a plurality of pegs provided on its upper surface in the longitudinal direction with equal intervals therebetween. On each of the pegs, one bobbin is supported perpendicularly, and the bobbins are thus kept separated from each other.

According to the above-mentioned technique, a plurality of the trays are aligned at the front of, for example, a draw-twisting machine in a direction parallel to the direction of the aligned arrangement of take-up spindles. Full size bobbins formed on the draw-twisting machine are then extracted from the take-up spindles and put on the pegs of the trays. The trays, on which the full size bobbins have been placed, are taken out of the front of the draw-twisting machine one by one and then placed successively on a transportation carrier which stands by at one longitudinal end of the draw-twisting machine. On the upper surface of the transportation carrier, a plurality of members for supporting the trays is fixedly provided so that one tray can be supported on each of the supporting members. When all of the trays taken out of the front of the draw-twisting machine have been supported on the supporting members of the transportation carrier, the movement of the carrier is started. Then, at the destination, the trays are taken off of the transportation carrier.

In the above-mentioned transportation technique, where draw-twisting machine having 72 take-up spindles on one side thereof is used, 72 bobbins are formed simultaneously. In such a case, if each tray has 8 pegs, 9 trays corresponding to the number of take-up spindles, must be provided, at the front of the draw-twisting machine.

The above-mentioned transportation technique has made it possible to save, to a fair extent, the manual labor and operation time for the transportation of yarn packages from a yarn package forming machine. However, this known technique still involves the following drawbacks.

(1) When yarn packages are transferred to a subsequent stage of the yarn processing, such as for finishing, inspection or storage, if this transfer operation is performed in single tray units, effective improvement of the transfer efficiency can not be expected because the transfer operation must be repeatedly carried out and, thus, a long time is required for completion of such operation. For example, where 72 bobbins are to be transferred using trays each capable of holding 8 bobbins as in the case mentioned above, the same transfer operation must be conducted repeatedly 9 times.

(2) if the transfer operation is performed in tray units, control at the other stages of the yarn processing, such as for the classification and selection of the full size yarn packages and the preparation of the fresh bobbins or tubes for forming the yarn packages, is complicated.

(3) For the reasons set forth in (1) and (2) above, it is difficult to save a great amount of manual labor.

(4) When yarn packages are stored in tray units, the storage equipment becomes complicated and a large area is necessary for storage, and both of these factors are very disadvantageous from the practical point of view.

It is an object of the present invention to provide an efficient method and apparatus for transporting yarn packages between successive stages of yarn processing whereby the above-mentioned drawbacks of the known transportation technique can be eliminated.

Another object of the present invention is to provide a method and apparatus for transporting yarn packages from a yarn package forming machine, whereby the yarn package forming stage can be systematically and functionally connected with the other stages of the yarn processing, such as for the inspection, classification and storage of the full size yarn packages, and the preparation of the fresh bobbins or tubes for forming the yarn packages, so that a great amount of manual labor is saved.

To attain the above-mentioned objects, and other objects which will be apparent from the following description, in the transportation method according to the present invention, a plurality of yarn packages is separately placed on a tray and a plurality of such trays is placed on a pallet, and then, the pallet is transported between successive stages of yarn processing. Such transportation by a pallet, whereon a plurality of trays is mounted with each tray having a plurality of yarn packages, is one of the essential conditions of the transportation method according to the present invention. In this transportation method, it is advantageous that the yarn packages be separately placed on each tray in a perpendicular condition. When this transportation method is applied to a yarn package forming machine such as a draw-twisting machine provided with a plurality of spindles, the disposition order of yarn packages on each tray coincides with the alignment order of spindles. Consequently, the origin of each yarn package can be easily identified, in other words, the feedback of the inspection result to the spindles of the yarn package forming machine can be easily attained. This is one of the important advantages of the method according to the present invention.

The transportation apparatus of the present invention comprises basically trays which are each capable of holding a plurality of yarn packages, a pallet whereon a plurality of the trays can be placed and a transportation carrier which is capable of moving with the pallet mounted thereon. For example, the apparatus may comprise a transportation carrier which is capable of moving along a transportation passage formed in a factory, a pallet displaceably mounted on the transportation carrier whereon a plurality of the above-mentioned trays can be placed and means for placing the trays on the pallet one by one, or for unloading the trays from the pallet one by one. In addition, if the above-mentioned transportation apparatus is adopted for connecting yarn package forming machines, such as draw-twisting machines provided with a plurality of spindles, conveying means for displacing a plurality of trays, each tray being provided with a plurality of pegs for holding yarn packages or fresh bobbins arranged in an alignment with an interval identical to a spindle interval, from positions corresponding to groups of spindles to the above-mentioned placing means, is desirably utilized. This conveying means is also capable of positioning the above-mentioned trays received from the above-mentioned placing means at positions corresponding to groups of spindles. If the disposing level of the conveying coincides with the disposing level of the pallet of the transportation carrier, the above-mentioned placing means can be omitted.

It is one of the advantages of the transportation method and apparatus according to the present invention that it is able to be effectively applied to the yarn package forming machines, such as a drawing machine, draw-twisting machine, spin-winding machine, spin-draw-winding machine, false-twisting machine, draw-false-twisting machine and the like.

FIG. 1 is a schematic layout drawing of a factory provided with a transportation passage for a group of yarn packages which connects a draw-twisting stage provided with a plurality of unit machines to other stages involving an inspection stage, classification stage, storing stage and the like, wherein the transportation method and apparatus according to the present invention are advantageously adopted;

FIGS. 2A and 2B are schematic views of a tray adopted for the transportation system shown in FIG. 1, wherein FIG. 2A shows a side view of the tray and FIG. 2B shows a bottom view thereof;

FIG. 2C is a top perspective view, and FIG. 2D is a bottom perspective view of the tray shown in in FIGS. 2A and 2B;

FIG. 3 is a schematic perspective view of the tray, shown in FIGS. 2A and 2B, with a plurality of full size yarn packages placed on a part thereof;

FIGS. 4A and 4B are schematic views of a pallet adopted for the transportation system shown in FIG. 1, wherein FIG. 4A shows a plan view of the pallet and FIG. 4B shows a side view thereof;

FIG. 5 is a schematic perspective view of the pallet, shown in FIGS. 4A and 4B, whereon a plurality of the trays holding full size yarn packages are placed;

FIG. 6 is a schematic side view of a take-up part of the draw-twisting machine and a front part thereof; adopted for the transportation system shown in FIG. 1;

FIG. 7 is a schematic front view of a part of the draw-twisting machine, a placing means and a transportation carrier, adopted for the transportation system shown in FIG. 1, illustrating the relative positions thereof;

FIG. 8 is a schematic plan view of a part of the draw-twisting machine provided with the placing means and the transportation carrier, shown in FIG. 7;

FIG. 9 is a schematic side view of the transportation carrier disposed at the related position shown in FIG. 7;

FIG. 10 is a schematic view of a tray conveyor disposed at the front of the draw-twisting machine along the aligned spindles;

FIGS. 11A, 11B and 11C are schematic views of a tray displacing mechanism mounted on the placing means, wherein FIG. 11A shows a side view thereof, and FIGS. 11B and 11C show enlarged views of the main parts thereof;

FIG. 12 is an enlarged side view schematically illustrating the main part of the transporting carrier shown in FIG. 9;

FIG. 13 shows schematic side views of successive steps of the transportation of yarn packages according to the invention, wherein full size bobbins are taken out from a draw-twisting machine and placed on a transportation carrier;

FIGS. 14A, 14B and 14C are block diagrams indicating actuating mechanisms when full size bobbins are taken out from a draw-twisting machine and placed on a transportation carrier;

FIG. 15 is a schematic plan view of the section Z shown in FIG. 1, involving the subsequent stages of the draw-twisting;

FIG. 16 shows schematic side views of successive steps of the transportation of yarn packages according to the the invention, wherein fresh bobbins are unloaded from a transportation carrier and supplied to a draw-twisting machine.

The term "yarn package" as used herein refers to various types of packages, such as bobbins, pirns, drums, cones, tubes, spools, cakes and cheeses, of yarns.

The method and apparatus for transporting a group of yarn packages according to the present invention will be hereinbelow illustrated by an embodiment thereof with reference to the accompanying drawings. The embodiment hereinbelow mentioned concerns a case where full size bobbins formed by a draw-twisting machine at a draw-twisting stage of a synthetic fiber yarn are transported to the subsequent stage such as for storage, inspection or classification.

Referring now to FIG. 1, a plurality of draw-twisting machines D.sub.1, D.sub.2, D.sub.3, . . . D.sub.n is arranged in parallel in a draw-twisting section in a factory. Transportation passages P.sub.1, P.sub.2, P.sub.3 and P.sub.4, along which a transportation carrier A runs, are provided surrounding the group of the draw-twisting machines. Passages P.sub.1 and R.sub.3 run along the direction of the arrangement of the draw-twisting machines, and passages P.sub.2 and P.sub.4 connect the passages P.sub.1 and P.sub.3 with each other. The passage P.sub.2 is also connected to another passage P.sub.5 passing through a section Z involving storage equipment for full size bobbins, a station for inspecting (or inspecting and classifying) the full size bobbins, a station for preparing fresh bobbins to be supplied and the like. The passage P.sub.1 is also connected to another passage P.sub.8 passing through a further section involving stages such as for finishing the draw-twisted yarns. The passage P.sub.5 is connected to the passage P.sub.1 by a passage P.sub.6, and the passage P.sub.6 is connected to the passage P.sub.4 by a passage P.sub.7. Between the longitudinal outer end of each of the draw-twisting machines D.sub.1 D.sub.2, D.sub.3 . . . D.sub.n and the passage P.sub.1, placing means C for exchanging trays between each draw-twisting machine and the transportation carrier A are provided.

The transportation carrier A which stands by at a predetermined position on the passage P.sub.4 runs along a selected transportation passage in accordance with a control signal issued from a control means (not shown). For example, when full size bobbins doffed from the draw-twisting machines are to be carried from the respective draw-twisting machines to a subsequent stage involved in the section Z, the transportation carrier A goes into the passage P.sub.1 from the passage P.sub.4 and stops at a position X or Y facing a placing means C disposed beside the prescribed draw-tristing machine. On the carrier A, a pallet is mounted and on this pallet, a plurality of trays holding fresh bobbins is placed. Then, the trays holding fresh bobbins are supplied to the draw-twisting machine from the pallet on the carrier by the placing means C. The emptied pallet then receives trays, whereon a predetermined number of full size bobbins are placed, through the placing means C. After the trays having the full size bobbins mounted thereon are placed on the pallet mounted on the carrier, the movement of the transportation carrier A to the section Z, via the passages P.sub.2 and P.sub.5, is started. Upon the carrier's arrival at the section Z, the full size bobbins mounted on the trays are unloaded together with the pallet.

On the other hand, in the section Z, another pallet is prepared whereon trays holding fresh bobbins are placed. The emptied transportation carrier A thus is able to receive a pallet having trays holding fresh bobbins placed thereon. Then, the carrier A goes into the passage P.sub.4 through the passage P.sub.6 and reaches the standby position, and then, waits for the next control signal. Where another transporting operation as mentioned above is required for another draw-twisting machine when the carrier A receives the fresh bobbin pallet, the carrier A goes into the passage P.sub.1 directly without passing through the passage P.sub.4 and is displaced to the next prescribed position X or Y.

The above explanation concerns an example of the running actions of the transportation carrier A. If the full size bobbins are to be carried to the above-mentioned further section involving, for example, a finishing stage, the transportation carrier A may run along the passage P.sub.1 and P.sub.8. If the full size bobbins are to be successively transported from any of the respective draw-twisting machines, the carrier may go into the passage P.sub.6, without unloading the pallet of full size bobbins mounted thereon, and into the passage P.sub.1, and then, be displaced to the next prescribed position X or Y where the above-mentioned placing operation is conducted.

Further, the transportation carrier A may run so that the fresh bobbin trays are supplied to one of the draw-twisting machines while the take-up operation is conducted on said draw-twisting machine and, then, the carrier A returns to the standby position on the passage P.sub.4. The transportation carrier A may also run in such a manner that the fresh bobbin trays are supplied to one of the draw-twisting machines while the take-up operation is conducted on said draw-twisting machine. Then, the carrier A is displaced to the next prescribed position X or Y corresponding to another draw-twisting machine whereon the doffing of full size bobbins is completed and at this position, the full size bobbin trays are loaded on the carrier A. Next, the transportation carrier A reaches the section Z where the full size bobbin pallet is unloaded and the fresh bobbin pallet is loaded. Then, the carrier A reaches the standby position.

The above-mentioned transportation operation is made by means of one transportation carrier. However, such transportation operation may be made by means of a plurality of transportation carriers which may be aligned in series on the passage P.sub.4. In such a case, the transportation operation may be made in such a manner that the first one of the transportation carriers is displaced to the prescribed position X or Y corresponding to one of the draw-twisting machines and at this position, the fresh bobbin trays are supplied to said draw-twisting machine and then, the carrier A returns to the standby position on the passage P.sub.4. Next, the second one of the transportation carriers is displaced to the prescribed position X or Y corresponding to another draw-twisting machine whereon the doffing of full size bobbins is completed and at this position, the full size bobbin trays are loaded on the second carrier. Then, the second carrier reaches the section Z where the full size bobbin pallet is unloaded and the fresh bobbin pallet is loaded. Then, the second carrier reaches the standby position. In this example, the transportation operation as mentioned above may further be repeated by means of the other transportion carriers which standby on the passage P.sub.4.

The drive passage selection of the transportation carrier A can be easily controlled by utilizing a recently developed control technique by a computor (not shown). For example, a control system may be advantageously utilized which is composed of a central processing unit and detecting means, such as limit switches and photoelectric devices which are provided, for example, on the draw-twisting machines, transportation carrier and passages, for providing operation start demand signals and operation end demand signals, i.e. operation detecting signals, to the central processing unit. However, since such control technique is not the subject matter of the present invention, the detailed explanation thereof is omitted.

As mentioned hereinbefore, it is one of the important features of the present invention to utilize the tray and the pallet in combination in the transportation of yarn packages. Thus, the tray and the pallet are next explained in detail.

Referring to FIGS. 2A, 2C, and 2D a tray 1 is provided with: a plate-shaped base 1d; upright pegs 1e, which are fixed to the base 1d and aligned with an equal interval therebetween; sliding surfaces 1c, which extend in parallel in the longitudinal direction at both sides of the base 1d, and also has on the longitudinal opposite ends thereof two pairs of vertical side walls 1g and 1f which are arranged to be inwardly inclined towards end plates 1a and 1b, respectively, and; end plates 1a, 1b which are projected upright at both longitudinal ends of the base 1d and provided with upwardly extending surfaces 1c. One full size bobbin or fresh bobbin is supported on each peg 1e. As is seen from FIG. 3, wherein the tray 1 with full size bobbins 2 placed on a part thereof is schematically shown, the full size bobbins on the tray are kept separate so that they do not contact each other.

FIGS. 4A and 4B show the above-mentioned pallet. In the figures, the pallet 3 is provided with: a plurality of tray-receiving zones 3a which are separated by partition walls 3b and on the surfaces of which the above-mentioned sliding surfaces 1c of the tray are slidable and; channels 3c which are formed in the bottom surface of the pallet 3 in the direction perpendicular to the direction of the receiving zones 3a so as to be engaged with rails of a slider of the transportation carrier A, which will be explained in detail hereinafter. On each receiving zone 3a, one tray is placed by being slid from one end of the zone.

Schematically shown in FIG. 5 is the pallet 3 whereon 9 trays each having 8 full size bobbins mounted thereon are placed.

For the sake of a better understanding of the present invention, more specific explanation will be given below on the basis of the assumption that: the existing draw-twisting machine has 72 spindles on each side of the spindle alignmments, one tray can hole 8 bobbins; 9 trays can be placed on one pallet; 9 trays holding fresh bobbins are aligned in the longitudinal direction at the front of the draw-twisting machine along the aligned spindles, and; each of the 72 pegs of the aligned 9 trays is positioned opposite to each one of the 72 spindles.

In FIGS. 6, 7, 8 and 9, the draw-twisting machine, the placing means, the transportation carrier, and the related parts thereof, are schematically shown together with their relative positions. The following explanations will be made mainly with reference to FIGS. 6, 7, 8 and 9 and also with reference to other appropriate figures specifically. As mentioned above, 9 trays each having 8 fresh bobbins mounted thereon are conveyed in the longitudinal direction at the front of the draw-twisting machine D so as to be positioned opposite to each group of 8 spindles. Referring to FIG. 6, the fresh bobbins 4 on the trays 1 are first transferred, by a known automatic doffing apparatus as disclosed, for example, in the above-mentioned Japanese Patent Publication No. 24812/74, onto stationary pegs 5b provided on the draw-twisting machine D facing corresponding spindles. Then, full size bobbins 2 are doffed from the spindles 5a of the draw-twisting machine D and transferred onto the pegs 1e of the emptied trays 1 by the automatic doffing apparatus. The fresh bobbins 4 on the stationary pegs 5b are then transferred by the automatic doffing apparatus onto the empties spindles 5a. Such bobbin-transferring operation may be conducted at a time with respect to all of the 72 spindles or successively with respect to each one of the 72 spindles or with respect to each group of 8 bobbins corresponding to the 8 pegs of one tray. Thus, the fresh bobbins 4 on the trays 1 supplied along the spindle alignment at the front of the draw-twisting machine D are all set onto the spindles 5a, and the full size bobbins 2 on the spindles 5a are also all set onto the pegs 1e of the trays 1. The level of the tray conveyor is lower than the level of the spindle alignment of the yarn package forming machine.

The trays 1 each having 8 full size bobbins 2 mounted thereon are conveyed on guide pulleys 6a to the longitudinal end of the draw-twisting machine D by a tray conveyor 6. The construction of the tray conveyor 6 is shown in FIGS. 6 and 10, wherein a plurality of the guide pulleys 6a is disposed on both sides of a tray-transferring passage provided along the spindle alignment of the draw-twisting machine D so as to form parallel guide passages for the sliding surfaces 1c of the tray 1. The tray conveyor 6 is also provided with a chain conveyor 6b between the guide pulley alignments on both sides of the tray-transferring passage. A hook 6c is provided on the chain conveyor 6b for engaging with the base of the tray 1. The base of the tray 1 is engaged by the hook 6c and, thus, the tray 1 is forced to move in the conveying direction of the chain conveyor 6b. The chain conveyor 6b is guide driven by driving sprocket wheels 6d, 6e and guide sprocket wheels 6f, 6g. A driving motor M (brake motor No. 1) is also shown in FIG. 10. The chain conveyor 6b can be driven intermittently, and the conveying direction thereof is selective.

The term "brake motor" as used herein refers to a motor provided with a brake mechanism.

At the longitudinal outer end of the draw-twisting machine D, a placing means C is disposed as mentioned hereinbefore. A transportation carrier A having the aforementioned pallet 3 (FIG. 4) mounted thereon stands by at the aforementioned position X or Y beyond the placing means C. Referring especially to FIGS. 7 and 8, the placing means C is provided with a lift 7 and a tray-displacing mechanism 8. The lift 7 is provided with an air cylinder 7a and a tray-supporting member 7b which is moved up and down by the action of the air cylinder 7a. The lift 7 is designed in such a way that one stroke of the air cylinder 7a, the upper surface of the tray-supporting member 7b takes two positions, one of which is a position of the level equal to the upper surface of the tray conveyor 6, and the other is a position of the level equal to the upper surface of the pallet 3 mounted on the transportation carrier A.

The placing means C is fixedly provided with a tray-displacing mechanism 8 as mentioned above. The construction of the tray-displacing mechanism 8 is shown in FIGS. 11A, 11B and 11C. The tray-displacing mechanism 8 is provided with an air cylinder 8a. The air cylinder 8a has a piston 8d which moves either to the right hand direction or to the left hand direction by the action of compressed air introduced into the cylinder from either of the air inlets 8b, 8c disposed at both of the end portions of the air cylinder 8a. A cord 8g is tightly connected to both ends of the piston 8d through guide wheels 8e, 8f. The cord 8g may be coated with, for example, an ethylene tetrafluoride resin to impart smoothness and wear resistance to the cord. A bracket 8i is fixedly disposed on the cord 8g. Said bracket 8i slides on a guide rod 8h fixedly arranged in parallel to the cord 8g. In addition, the bracket 8i is provided with a tray-holding arm 8k which is pivotably supported around a fixed axis 8j. An air cylinder 8m is pivotably supported around another axis 8l on the bracket 8i, and the end portion of a rod 8n of the air cylinder 8m is pivotably fixed to the tray-holding arm 8k by a pin 8p so that the tray-holding arm 8k can be pivoted by the motion of the air cylinder 8m from a position indicated, in FIG. 11B, by solid lines to a position indicated, in FIG. 11B, by dot-dashed lines. The end portion of the tray-holding arm 8k forms a forked holding member 8q which can be engaged with the aforementioned end plate 1a or 1b of the tray 1 as shown in FIG. 11C.

As mentioned above and as shown in FIG. 8, a transportation carrier A stands beside the placing means C. The transportation carrier A comprises a driving truck 9a such as a battery driven truck and a carrier 9b connected to the driving truck 9a. A slider 9d which moves slidably along channels 9c is disposed on the upper surface of the carrier 9b. The slider 9d is engaged with a screw shaft 9e driven by a brake motor (brake motor No. 2) (not shown) and is stepwise moved to the arrow direction. As is shown in detail in FIG. 12, the screw shaft 9e is engaged with a flange 9f fixed on the slider 9d; two rails 9g engaged with the aforementioned channels 3c (FIG. 4A) of the pallet 3 are provided on the upper surface of the slider 9d; and further, nine photo-receivers 9h receiving light rays from a photo-projector (not shown) provided on the draw-twisting machine are provided in the side wall of the slider 9d. The mounting center of each of the photo-receivers 9h coincides with the center of each tray-receiving zones 3a of the pallet 3 mounted on slider 9d. Furthermore, the slider 9d moved into the channels 9c by the screw shaft 9e is designed in such a way that the slider 9d stops when one of the photo-receivers 9h receives a light ray from the photo-projector. At this time, the center of the aforementioned tray conveyor 6 (FIG. 6) coincides exactly with the center of the tray-receivng zone 3a of the pallet 3.

As hereinbefore mentioned, the trays 1 having full size bobbins 2 mounted thereon are conveyed to the longitudinal outer end of the draw-twisting machine D by the tray conveyor 6. The loading operation of the trays 1 onto the pallet 3 will be explained below with reference to FIGS. 6, 7, 8, 9, 10, 11A, 11B, 11C, 12 and 13.

The first one of the 9 trays 1 holding full size bobbins 2 is initially transferred onto the tray-supporting member 7b of the lift 7 of the placing means C by the tray conveyor 6 (FIG. 13 1). The other trays 1 are still placed on the tray conveyor 6.

Secondly, the lift 7 is moved up by the motion of one stroke of the air cylinder 7a to a level at which the upper surface of the tray-supporting member 7b of the lift 7 is coincident with the upper surface of the pallet 3 (FIG. 13 2).

Thirdly, the tray-holding arm 8k is pivoted, from a position indicated by solid lines to a position indicated by dot-dashed lines in FIG. 11B, by the motion of the air cylinder 8m of the tray-displacing mechanism 8 and, thus, the holding member 8q of the arm is engaged with the end plate 1a (or 1b) of the tray 1 (FIG. 13 3).

Fourthly, compressed air is introduced into the cylinder of the air cylinder, 8a of the tray-displacing mechanism 8 from the air inlet 8c. Fifthly, the piston 8d is moved to the left hand direction of FIG. 11A; the bracket 8i is moved to the right hand direction of FIG. 11A while being guided by the guide rod 8h. Thus, the tray 1 placed on the tray-supported member 7b of the lift 7 is pushed away from the tray-supporting member surface and set in the first one of the receiving zones 3a of the pallet 3 mounted on the transportation carrier A (FIG. 13 4).

Sixthly, the tray-holding arm 8k is reinstated to the original position, indicated in FIG. 11B by solid lines, by the motion of the air cylinder 8m of the tray-displacing mechanism 8. Compressed air is then introduced from the other air inlet 8b of the air cylinder 8a of the tray-displacing mechanism 8, and, thus, the bracket 8i is moved to the left hand direction of FIG. 11A so as to be reinstated back to the original position while being guided by the guide rod 8h (FIG. 13 5).

Seventhly, the lift 7 is moved down by the motion of the air cylinder 7a to reinstate said lift to its original position at which it was positioned before being moved up (FIG. 13 6). At this time, the screw shaft 9e is rotated by the motion of the brake motor (not shown) for driving the slider 9d of the transportation carrier A, and, thus, the slider 9d is moved into the direction of the arrow shown in FIGS. 8 and 9. When the second one of the photo-receivers 9h receives the light ray from the photo-projector (not shown) provided on the draw-twisting machine D, the brake motor stops rotating and then the rotation of the screw shaft 9e stops. Thus, the preparation for the operation of transferring the second one of the trays 1 onto the pallet 3 is completed.

Eighthly, the second tray 1 is pushed away from the front of the draw-twisting machine D onto the tray-supporting member 7b of the lift 7 by the motion of the tray conveyor 6 (FIG. 13 7). The above-mentioned operation is then successively repeated, and, thus, all of the 9 trays are loaded onto the pallet 3.

The above-mentioned tray-transferring operation may be carried out automatically using, for example, an electrical control mechanism. An embodiment of such a control mechanism will be explained below with reference to FIGS. 14A, 14B and 14C, specifically.

FIG. 14A is a block diagram indicating the actuating mechanism utilized which operates during when the trays 1 are being transferred from the front of the draw-twisting machine onto the tray-supporting member 7b of the lift 7. The rotation of the brake motor No. 1 is started when a signal is given through a relay R.sub.O and a timer T.sub.2, which signal is issued when the doffing operation is completed. Thus, the tray conveyor 6 is driven and the tray 1 is transferred onto the lift 7 which is at the moved-down level. When the tray 1 is placed on the lift 7, a limit switch LLS.sub.2 which is provided on the frame of the placing means C is actuated by a lift actuator A.sub.2 which is the end plate 1a (or 1b) of the tray 1 and a relay R.sub.1 is then released by a signal issued from the limit switch LLS.sub.2 to stop the rotation of the brake motor No. 1.

When the lift 7 is moved down after the lift 7 is moved up and the tray 1 is placed onto the pallet on the transportation carrier, a limit switch LLS.sub.1 which is provided on the frame of the placing means C underneath the lift 7, as shown in FIG. 7, is actuated by a tray conveyor actuator A.sub.1 which is the bottom surface of the tray-supporting member 7b. A relay R.sub.1 is then closed by a signal issued from the limit switch LLS.sub.1 so that a signal is issued for starting the rotation of the brake motor No. 1 which drives the tray conveyor 6.

FIG. 14B is a block diagram indicating the actuating mechanism which operates during when the tray is transferred from the tray-supporting member 7b of the lift 7 onto the receiving zone 3a of the pallet 3. When the transportation carrier A reaches the prescribed position X or Y mentioned hereinbefore, a limit switch LS provided on the frame of the transportation carrier A is actuated by a carrier actuator A.sub.4 provided beside the transportation passage P.sub.1. Then, a relay R.sub.O is closed by a signal issued from the limit switch LS for issuing a signal for starting the rotation of the brake motor No. 2 on the transportation carrier A through a timer T.sub.3. Thus, the brake motor No. 2 is rotated to move the slider 9d on the transportation carrier A in the direction opposite to the arrow in FIG. 8 so that the pallet 3 is displaced to the position indicated in FIG. 8. When the slider is moved to a position at which the first one of the photo-receivers 9h receives the light ray from the photo-projector on the draw-twisting machine, a signal is issued from a signal generator E.sub.1 which is disposed in the first photo-receiver thereby releasing the relay R.sub.2. Thus, the rotation of the brake motor No. 2 is stopped and the center of the first one of the tray-receiving zones 3a of the pallet 3 on the slider 9d becomes coincident with the center of the tray conveyor 6 so that the first receiving zone 3a is ready for receiving the first tray on the tray-supporting member 7b of the lift 7.

When the first tray on the tray-supporting member 7b of the lift 7 is pushed and set in the first tray-receiving zone 3a of the pallet 3, a limit switch PLLS provided on the frame of the carrier 9b of the transportation carrier A is actuated by a pallet actuator A.sub.3 which is the end plate 1a (or 1b) of the first tray 1. Then, the relay R.sub.2 is closed by a signal issued from the limit switch PLLS so that the brake motor No. 2 is again rotated by a signal issued from the relay R.sub.2 for moving the slider 9d on the transportation carrier A. When the slider is moved to the next position at which the second one of the photo-receivers 9h receives the light ray from the photo-projector on the draw-twisting machine, a signal is issued from a signal generator E.sub.2 which is disposed in the second photo-receiver whereby the relay R.sub.2 is again released for stopping the movement of the slider 9d. Then, the above-mentioned operation is repeated.

FIG. 14C is a block diagram indicating the mechanism for actuating the air cylinders provided on the placing means C. When the limit switch LLS.sub.2 is actuated as mentioned above, a signal issued from the limit switch LLS.sub.2 is actuated as mentioned above, a signal issued from the limit switch LLS.sub.2 is applied to a relay R.sub.3 through a timer T.sub.4 so that the relay R.sub.3 is closed to excite a magnet valve No. 1 connected to the air cylinder 7a shown in FIG. 7 (air cylinder No. 1). Thus, the air cylinder No. 1 (air cylinder 7a) is actuated and the lift 7 is moved up. A relay R.sub.4 is closed later than the relay R.sub.3 by a signal applied from the limit switch LLS.sub.2 through a timer T.sub.5. Thus, a magnet valve No. 2 connected to the air cylinder 8m shown in FIG. 11B (air cylinder No. 2), is excited thereby actuating the air cylinder No. 2 (air cylinder 8m). The tray-holding arm 8k then becomes engaged with the end plate 1a (or 1b) of the tray 1. Next, a relay R.sub.5 is closed later than the relay R.sub.4 by a signal applied from the limit switch LLS.sub.2 through a timer T.sub.6 so that a magnet valve No. 3 connected to the air cylinder 8a shown in FIG. 11A (air cylinder No. 3) is excited. The air cylinder No. 3 (air cylinder 8a) is thereby actuated to push the tray 1 engaged with the pg,24 tray-holding arm 8k into the tray-receiving zone 3a of the pallet 3.

When the tray 1 is set in the receiving zone 3a, the limit switch PLLS is actuated as mentioned above. Thus, the relay R.sub.3 is released by a signal applied from the limit switch PLLS through a timer T.sub.7 to excite the magnet valve No. 1 and actuate the air cylinder No. 1 in the opposite direction, while in a similar way the air cylinder No. 2 and the air cylinder No. 3 are actuated in the opposite direction.

As explained hereinbefore with reference to FIG. 1, the transportation carrier A having full size bobbins mounted thereon is displaced to the section Z which involves the subsequent stages of the yarn processing, via the transportation passages P.sub.2 and P.sub.5. FIG. 15 schematically shows the section Z.

The section Z comprises warehouses 10a for storing the pallets having full size bobbins placed thereon, warehouses 10b for storing the pallets having fresh bobbins placed thereon, a station 10c for inspecting and classifying the full size bobbins and a station 10d for preparing fresh bobbins to be supplied to the draw-twisting machines. The warehouses 10a and 10b, the inspection and classification station 10c and the preparation station 10d are connected to each other through a conveyor 10e. Further, cranes 10f are provided between the warehouses 10a and the warehouses 10b.

The full size bobbins conveyed to the section Z by the transportation carrier A are unloaded together with the pallet 3 by means of the crane 10f and entered into the warehouse 10a. Then, a pallet having trays holding fresh bobbins mounted thereon is taken out from the warehouse 10b disposed opposite to the warehouse 10a and then loaded on the transportation carrier A also by means of the crane 10f. Thereafter, the transportation carrier A, whereon the pallet having fresh bobbins placed thereon is mounted, goes into the transportation passage P.sub.6 as explained with reference to FIG. 1.

The full size bobbins once entered into the warehouse 10a are taken out, as desired, together with the pallet and placed on the conveyor 10e by the crane 10f. The full size bobbins conveyed together with the pallet on the conveyor 10e are pulled out from the pegs of the trays mounted on the pallet, inspected and classified at the inspection and classification station 10c and, then, conveyed to the subsequent packing stage. On the pegs of the emptied trays on the pallet, fresh bobbins are placed at the preparation station 10d. The pallet having fresh bobbins mounted thereon is conveyed on the conveyor 10e and entered into the warehouse 10b by means of the crane 10f.

By the way, as hereinbefore explained with reference to FIG. 1, the transportation carrier A, whereon trays having fresh bobbins placed thereon are loaded at the section Z, goes into the transportation passage P.sub.1 via the passage P.sub.6 and stops at a position X or Y facing toward a draw-twisting machine from which full size bobbins are to be taken out next. Then, the 9 trays having fresh bobbins placed thereon are supplied to the draw-twisting machine one by one. The supply of the tray can be carried out in a way which is substantially the same as in the above-mentioned case where full size bobbins are taken out from a draw-twisting machine, except that the sequence of operation is reversed. Thus, the operation in this case will be briefly explained below with reference mainly to FIG. 16.

The transportation carrier A, whereon the pallet having the trays holding fresh bobbins placed thereon is mounted, stops at a prescribed position X or Y (FIG. 16 1).

Then, the lift is moved up to a level at which the trays on the pallet can be received (FIG. 16 2).

Then, the tray-holding arm of the tray-displacing mechanism is moved in the direction toward the pallet (FIG. 16 3).

Next, the tray-holding arm is pivoted and engaged with the end plate of the tray (FIG. 16 4), and then, pulls out the tray onto the tray-supporting member of the lift (FIG. 16 5).

Then, the lift is moved down to the original level (FIG. 16 6).

Next, the tray on the tray-supporting member is engaged with the hook 6c of the tray conveyor 6 (c.f. FIGS. 6 and 10), and then, supplied to the front of the spindle alignment of the draw-twisting machine (FIG. 16 7). At the same time, the slider on the transportation carrier is moved for a length corresponding to the width of the tray-receiving zone of the pallet so that the second one of the trays is taken out from the pallet. Then, the above-mentioned operation is successively repeated to align the trays on the tray conveyor at the front of the draw-twisting machine.

This operation may also be carried out automatically in the manner as mentioned hereinbefore with reference to FIGS. 14A, 14B and 14C. The subsequent doffing operation may also be carried out as hereinbefore mentioned.

In the embodiment explained above in detail, bobbins are transported between the draw-twisting stage and subsequent stage of the draw-twisting processing of yarns. However, it should be noted that the invention is not limited to only such an embodiment. Accordingly, the yarn package forming machine should not be limited to only a draw-twisting machine but should also include a drawing machine, spin-winding machine, spin-draw-winding machine, false-twisting machine, draw-false-twisting machine or the like. The invention can also be applied to the transportation of yarn packages between the successive yarn processing machines of different types.

Further, in the above-mentioned embodiment, if the level of the tray conveyor at the front of the draw-twisting machine is disposed to coincide with the level of the pallet on the transportation carrier, the lift of the placing means disposed between the machine and the carrier is apparently not necesssary.

The tray may be designed in such a way that the bobbins are supported horizontally, as long as the bobbins are kept separate so that they do not contact each other. If full size bobbins contact each other or a portion of the tray, the wound yarns may disadvantageously be soiled or broken. The tray is preferably designed so that the bobbins are perpendicularly supported as in the above-mentioned embodiment, since many of the conventional yarn package processing machines such as the aforementioned known doffing apparatus are designed to process yarn packages in a perpendicular state.

The pallet may be designed to receive any number of trays. However, since it is usual that an identical kind of yarn is processed on one yarn processing machine, if the machine has take-up means aligned on both sides as in the mentioned draw-twisting machine, it is preferred that the pallet be designed in such a way that all of the yarn packages from at least one side of the machine are transported as one unit. In such a case, the labeling process of the formed yarn packages becomes an easy operation, and the space required for storing the formed yarn packages can be greatly reduced.