ROVING BOBBIN EXCHANGING METHOD AND APPARATUS FOR CARRYING OUT ROVING BOBBIN EXCHANGING METHOD

Abstract: A method for exchanging roving bobbins in a spinning frame, wherein a unit operation includes a series of step operations for exchanging a pair of almost exhausted robing bobbins (2B, 2F) suspended by front and back bobbin hangers (12) facing each other in the creel for two adjacent full packaged roving bobbins, corresponding to the above pair of roving bobbins (1), of the supply rail (13) arranged at a position in front and above the creel. The unit operation is intermittently but successively carried out along the spindle alignment of the spinning frame from one side-end to the other. In this unit operation, it is inevitable to use a pair of pegs (35, 36) for supporting a pair of roving bobbins in a manner allowing changing of the axial distance of these pegs between a distance identical to an axial distance between a front bobbin hanger and a back bobbin hanger, facing each other in the creel, and a distance indentical to an axial distance between two adjacent bobbin hangers on the supply rail (13). Also, an apparatus provided with a peg unit (40) having the above two pegs (35, 36) together with mechanism (60) for changing the axial distance between these two pegs. Th e apparatus is further provided with an additional mechanism (70) for displacing the peg unit to desired positions to carry out the unit operation for exchanging roving bobbins, and a mechanism (90) for displacing the apparatus along the spinning frame to carry out the successive unit operations for exchanging roving bobbins from one side-end to the other of the spinning frame.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roving bobbin exchanging method for a spinning frame and an apparatus for carrying out the roving bobbin exchanging method. More particularly, the present invention relates to a roving bobbin exchanging method for exchanging a pair of almost exhausted roving bobbins suspended by the front and back bobbin hangers of a creel of a spinning frame for a pair of full packaged roving bobbins suspended by the bobbin hangers of a supply rail extended in front and above the creel. Description of the Related Art When roving bobbins suspended by the bobbin hangers of a spinning frame become almost exhausted, they must be exchanged for full packaged bobbins. Automation of the roving bobbin exchanging operation for spinning machines has been eagerly sought to reduce the manpower needed in the spinning process. For example, Japanese Unexamined Patent Publication (Kokai) No. 61-102428 discloses a roving bobbin exchanging method applied to a spinning frame wherein, at each side of the frame, front and back rows of bobbin hangers of a creel are arranged along the longitudinal direction of the frame to supply rovings to the corresponding draft parts of the corresponding side of the frame. Two rows of supply rails are arranged along each creel of the frame. A pair of front and back roving bobbins suspended by the corresponding bobbin hangers, one of which is supported by the front row and the other by the back row, are exchanged for full packaged roving bobbins suspended by the corresponding bobbin hangers of the supply rails, one of which is supported by the front supply rail and the other by the back supply rail. The above-mentioned bobbin exchanging operation is carried out sequentially from one end to the other of the spinning frame. Japanese Unexamined Patent Publication (Kokai) No. 61-119728 discloses another roving bobbin exchanging method applied to an identical spinning frame, except in that a single supply rail is utilized instead of the two rows of supply rails. In this invention, alternate pairs of roving bobbins arranged in front and back rows, respectively, at regular bobbins pitches along the longitudinal direction of a spinning frame are exchanged for corresponding adjacent two full packaged roving bobbins suspended by the bobbin hangers of the single supply rail when the alternate pairs become almost exhausted. The method disclosed in the above Japanese unexamined patent publications employ two pairs of pegs, namely, a pair of pegs for displacing a pair of almost exhausted roving bobbins and a pair of pegs for displacing a pair of full packaged roving bobbins, to carry out the roving bobbin exchanging operation. In the case of merely exchanging exhausted roving bobbins for full packaged roving bobbins, the utilization of two pairs of pegs pases no problem. However, for example, when an automatic piecing operation of rovings is carried out before the above-mentioned roving bobbin exchanging operation, if the free end of the roving of each full packaged roving bobbin suspended by a bobbin hanger of the supply rail is first caught and then introduced to a running roving from an almost exhausted roving bobbin suspended by a corresponding bobbin hanger of the creel and pieced with the above-mentioned running roving at a position upstream of the corresponding draft part, the operation for exchanging the almost exhausted roving bobbin for the full packaged roving bobbin is then carried out, and, thereafter, the roving bobbin exchanging operation is carried out for other pairs of almost exhausted roving bobbins suspended by a front bobbin hanger or a back bobbin hanger, facing each other, of a spinni ng frame, as a unit operation and the unit operation successively is caused out along the creel from one end to the other of the spinning frame, the device for exchanging the roving bobbins mounted on the apparatus becomes complicated in construction. It becomes difficult to mount a device for carrying out the above roving piecing operation on the same frame. For example, as shown in Japanese Unexamined Patent Publication (Kokai) No. 61-119728, it is necessary to change the alignment direction of two pegs forming a pair. Thus, a complicated mechanism must be used. Because of this, the motion of mounting two full packaged roving bobbins on the corresponding bobbin hangers of the spinning frame cannot be carried out simultaneously with the motion of mounting the exhausted roving bobbins on the corresponding bobbin hangers of the supply rail for the above unit operation. The solve the above-mentioned problem, when alternate pairs of roving bobbins suspended by the bobbin hangers of the spinning frame, one bobbin suspended by the bobbin hanger of the front row and the other one by the bobbin hanger of the back row, are almost exhausted they are exchanged for the adjacent two full packaged roving bobbins suspended by the bobbin hangers of a supply rail disposed along the longitudinal direction of the spinning frame at the adjacent position in front and above of the creel of the spinning frame. In this roving bobbin exchanging operation, a pair of empty bobbin hangers is displaces together with the bobbin hangers holding full packaged roving bobbins to the position for the bobbin exchanging operation at the supply rail. This pair of empty bobbin hangers is positioned immediately upstream of the above-mentioned working position before starting the roving bobbin exchanging operation. In the bobbin exchanging operation, the first pair of exhausted roving bobbins, located at the outermost side of the spinning frame, is taken off from the bobbin hangers of the creel in the spinning frame by a pair of pegs and then carried to positions facing the corresponding empty bobbin hangers mentioned above by displacing the pegs. The exhausted roving bobbins are thus suspended by these empty bobbin hangers. Next, these pegs are displaced to a position immediately below the corresponding pair of full packaged roving bobbins suspended by corresponding two adjacent bobbin hangers of the supply rail. These pegs are then displaced upward to separate the full packaged roving bobbins from the bobbin hangers of the supply rail. After transferring the full packaged roving bobbins from the above-mentioned bobbin hangers to the corresponding pegs, these pegs are then displaced to the corresponding position immediately below the corresponding pair of bobbin hangers of the creel from which the exhausted roving bobbins have been taken off. Thereafter, these pegs are displaced upward so that the bobbins are suspended form the bobbin hangers. The above-mentioned unit bobbin exchanging operation is successively carried out in a cyclical fashion by displacing the roving bobbin exchanging apparatus from one side to the other of the spinning frame. SUMMARY OF THE INVENTION It is an object of the present invention to provide a roving bobbin exchanging method solving the problems of the prior art. It is an additional object to provide a method for carrying out the roving bobbin exchanging operation with a roving-piecing operation. It is a further object to provide an apparatus for carrying out the above roving bobbin exchanging method and to provide a roving bobbin exchanging apparatus which can be incorporated with a roving-piecing apparatus. To carry out the above roving bobbin exchanging method according to the present invention, a pair of pegs is utilized. That is, in this method, a pair of empty bobbin hangers is previously prepared at the supply rail immediately upstream and outside of a group of bobbin hangers suspending full packaged roving bobbins for carrying the roving bobbins on a creel of a spinning frame from the stream side. A first pair of almost exhausted roving bobbins, located at a position most upstream of the creel, one bobbin suspended by a front bobbin hanger and the other by a back bobbin hanger, facing each other in the creel, is transferred to the above two pegs. Thereafter, these two are transferred to the above two empty bobbin hangers of the supply rail by displacing these pegs to positions immediately below the empty bobbin hangers. Then, they are displaced upward to transfer these almost exhausted roving bobbins to the empty bobbin hangers. During this transferring operation from the bobbin hangers of the creel to the bobbin hangers of the supply rail, the axial distance between the front bobbin hanger and back bobbin hanger facing each other in the creel is changed to the axial distance between two adjacent bobbin hangers. After the above operation, the two pegs are displaced to positions immediately below the corresponding full packaged roving bobbins suspended by two adjacent bobbin hangers of the supply rail, facing the pair of bobbin hangers from which the almost exhausted roving bobbins have been taken. During this operation, the axial distance between these pegs does not have to be changed. After transfer, these full packaged roving bobbins are carried to the positions immediately below the corresponding empty bobbin hangers mentioned above. During this displacing operation of the full packaged roving bobbins, the axial distance between these pegs is changed to a distance identical to the axial distance between the empty bobbin hangers facing each other in the creel. Therefore, by displacing these pegs upward, the full packaged roving bobbins are caught by the empty bobbin hangers. Then, by displacing these pegs downwards, the transfer operation of these full packaged roving bobbins to the pair of empty bobbin hangers of the creel is completed. According to this first unit operation to exchange roving bobbins, a fresh pair of empty bobbin hangers is created in the supply rail at the adjacent downstream position of the first pair of bobbin hangers to which the first transfer operation of almost exhausted roving bobbins was applied. Accordingly, when the second unit operation for exchanging roving bobbins is carried out for the next pair of almost exhausted roving bobbins suspended by the next pair of bobbin hangers in the creel, the above-mentioned fresh empty bobbins are utilized to receive the almost exhausted roving bobbins carried by the above-mentioned pegs as one step of the second unit operation. The third unit operation, the forth etc. are carried out successively as mentioned above, along the creel of the spinning frame. When the last unit operation is carried out, two empty bobbin hangers remain at the downstream end of the grouped bobbin hangers of the creel. As a modification of the above method, it is also possible to temporarily hold a pair of almost exhausted roving bobbins, before creating the above-mentioned empty bobbin hangers on the supply rail, in the first unit operation. In this case, the temporarily held roving bobbins are transferred to the empty bobbin hangers created by the last unit operation. To carry out the above method of the present invention, the apparatus for exchanging roving bobbins according to the present invention is provided with very unique peg unit comprising a pair of pegs, a sliding mechanism mounting these pegs in a condition allowing change of the axial distance therebetween, and a telescopic mechanism for actuating this sliding mechanism. By actuating this telescopic mechanism, the axial distance can be changed between a first distance identical to an axial distance between a front bobbin hanger and a back bobbin hanger, facing each other in the creel, and a second distance identical to the axial distance between two adjacent bobbin hangers of the supply rail. For each peg of the peg unit to catch a roving bobbin by from the corresponding bobbin hanger of the creel, or from the corresponding bobbin hanger of the supply rail, or transfer a roving bobbin to the bobbin hanger, it is necessary to position the peg immediately below the bobbin hanger. To attain this purpose, beside the above-mentioned unique peg unit, a mechanism for lifting this peg unit and a mechanism for turning this peg unit about a supporting axis of the peg unit are also included. By these mechanisms carry out the unit roving bobbin exchanging operation. This apparatus is also provided with a mechanism for displacing this apparatus intermittently, but successively, form one side end of the creel to the other such that the apparatus is stopped at a position in front of each pair of almost exhausted roving bobbins of the creel. After completion of the unit operation for exchanging roving bobbins, the apparatus is displaced to the next downstream position. BRIEF EXPLANATION OF THE DRAWINGS Fig. 1 is a side elevation of a spinning frame to which a pair of roving bobbin exchanging apparatuses of a first embodiment according to the present invention are mounted; Fig. 2 is schematic plan view of the roving apparatus shown in Fig. 1; Fig. 3 is a general front elevation of a peg unit in the apparatus shown in Fig. 1; Fig. 4 is partly sectional front elevation taken along a line IV-IV in Fig. 3, which illustrated a mechanism for actuating the peg unit of the apparatus shown in Fig. 1; Fig. 5 is a schematic sectional view showing a mechanism for moving a second slider relative to a first slider at a speed twice that of the first slider, in the peg unit shown, taken along a line V-V in Fig. 3; Fig. 6(A) and 6(B) are a front elevation and a side elevation, respectively, generally showing the second slider together with the first slider; Figs. 7(A) and 7(B) are a plan view and a side elevation, respectively, showing a mechanism for urging the second peg provided on the second slider toward the first peg provided on the first slider; Fig. 8A is a front elevation showing the general construction of a modified embodiment of a peg unit having a sliding mechanism provided with a first slider and a second slider, Fig. 8B is a front elevation of the first slider of the sliding mechanism shown in Fig. 8A, which indicates the relationship between a collar and hook and a stopper pin, and Fig. 8C is a fragmentary sectional view taken along a line C-C in Fig. 8A, which indicates the relationship between a collar and a first slider in the peg unit shown Fig. 8A; Fig. 9 is a schematic plan view showing the positional relationship between the apparatus shown in Fig. 1 and roving bobbins on the creel and supply rail of a spinning frame, when carrying out a method of a first embodiment according to the present invention; Figs. 10A to 10H are diagrammatic illustrations indicating the steps of a roving bobbin exchanging operation to be executed by the method and apparatus in the first embodiment; Fig. 11 is a longitudinal sectional view of an apparatus of a second embodiment according to the present invention; Fig. 12 is a schematic front elevation of the apparatus shown in Fig. 11; Fig. 13 is a schematic plan view showing the positional relationship between the apparatus shown in Fig. 11 and roving bobbins on the creel and supply rails of a spinning frame; Figs. 14A to 14B are diagrammatic illustrations indicating the steps of a roving bobbin exchanging operation to be executed by the method and apparatus of the second embodiment; and Fig. 15 is schematic plan view of a bobbin supporting member utilized for a modified embodiment of the apparatus according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS A detai explanation of the present invention is hereinafter explained with reference to the attached drawings. In the following explanation, the present invention is applied to a conventional ring spinning frame provided with identical spinning mechanisms at the two sides with respect to the longitudinal direction of the machine frame. To simplify the explanation, an application of the present invention to the spinning mechanism mounted on one side of the spinning frame only is explained. In a roving bobbin exchanging method and apparatus of a first embodiment of the present invention, a single supply rail is extended in front and above a creel of a spinning frame. Referring to Fig. 1, creel pillars 4 are disposed perpendicularly on the frame 3 of a spinning frame at appropriate intervals along the longitudinal center line of the frame 3. A supply rail 13 is held so as to extend along the longitudinal direction of the frame 3, on the free ends of rail brackets 7 attached to the upper ends of the creel pillars 4. The supply rail 13 is a hollow beam member having a substantially U-shaped cross-section with an elongated opening along the lower side thereof. A bobbin carriage 14 is a displaceably engaged in the elongated opening for travel along the supply rail 13. The bobbin carriage 14 carries bobbin hangers arranged at the same axial distance as between a front bobbin hanger 12 and a back bobbin hanger 12, facing each other in the creel. The number of bobbin hangers carried on the bobbin carriage 14 is greater by two than the number (n) of the bobbin hangers in the front row of the creel, that is No. = n + 2. Before starting the roving bobbin exchanging operation, a fixed number of full packaged roving bobbins 1 corresponding to the number n of the bobbin hangers 12 in the front row are hung on the bobbin carriage 14. The bobbin carriage 14 is stopped at a position such that the full roving bobbins 1 are located opposite the intervals between the adjacent two bobbin hangers 12 on the creel, respectively, as shown in Fig. 9. On the other hand, three supporting pipes 11a and 11b, and 11c are disposed on L-shaped supporting bars 9, each having one end connected to the corresponding free end of the rail bracket 7 and the other end connected to a support bracket 8 secured to the creel pillar 4 at a position above the middle part thereof. The bobbin hangers 12 for suspending roving bobbins are arranged at predetermined intervals on the supporting pipes 11a and 11c, and roving guides 10 arranged on the supporting pipe 11b. To carry out the roving bobbin exchanging operation in the first embodiment of the present invention, at the start of the spinning operation, roving bobbins having two different sizes, i.e., a half-exhausted condition, hereinafter referred to as half-exhausted roving bobbin, and a full packaged condition, hereinafter referred to as full packaged roving bobbin, are suspended alternately by pairs of bobbin hangers 12 facing each other in the creel along the longitudinal direction of the spinning frame, with regard to each side of the spinning frame. When the above-mentioned half-exhausted roving bobbins become almost exhausted or exhausted, each pair of these roving bobbins 2F, 2B, facing each other is exchanged for a pair of full packaged roving bobbins 1, which are adjacently suspended by two bobbin hanger 15 supported by the bobbin carriage 14 of the supply rail 13, simultaneously, pair by pair along the row of spindles. The almost exhausted or exhausted roving bobbins suspended by the bobbin hangers 15 of the front row are referred to as 2F, and those of the back row as 2B. In the following description, the above-mentioned exhausted or almost exhausted roving bobbins are referred to as merely "exhausted roving bobbins" to simplify the description, unless otherwise specified. The roving bobbin exchanging method in accordance with the present invention employs a roving bobbin exchanging apparatus 30 which is capable of travelling along the front si de of the spinning frame, namely, along the alignment of spindles 20. The roving bobbin exchanging apparatus 30 is provided with a body 31 with a wheel 32 mounted at the bottom thereof and guide rollers 24 on the side thereof facing the spinning frame, as shown in Fig. 1 and 2. The body 31 of the roving bobbin exchanging apparatus 30 is further provided with a drive motor (not shown) to drive the body 31 and displace the apparatus 30 per se along the longitudinal direction of the spinning frame and a scroll cam cooperating with the drive motor. A guide rail 23 is supported on brackets 22 secured to a spindle rail 21 of the spinning frame, and a plurality of guide pins 25 are studded securely in the outer surface of the guide rail 23 at regular intervals corresponding to the pitch between two adjacent bobbin hangers 12 along the longitudinal direction the spinning frame. The guide rollers 24 roll on the guide rail 23 and the scroll cam engages the guide pins 25. Thus, when the scroll cam is rotated, the roving bobbin exchanging apparatus 30 moves along the row of the spindles of the spinning frame. The roving bobbin exchanging apparatus 30 is stopped intermittently at predetermined positions to carry out the roving bobbin exchanging operation. The constitution of the roving bobbin exchanging apparatus 30 will be explained hereinafter. The roving bobbin exchanging apparatus 30 is equipped with functional devices for carrying out the roving bobbin exchanging operation in a predetermined sequence, whereby each pair of exhausted roving bobbins 2F, 2B facing each other are exchanging for a pair of full packaged roving bobbins 1, which are adjacently suspended by the bobbin hangers 15 supported by the bobbin carriage 14 of the supply rail 13, simultaneously, pair by pair along the row of spindles, and a drive mechanism for driving those functional devices. Referring to Figs. 1, 2, and 3, the roving bobbin exchanging apparatus 30 is provided with a peg unit 40 which comprises a slider mechanism to which a pair of pegs 35, 36 is mounted so as to enable changing of the axial distance therebetween, and a telescopic mechanism for actuating the slider mechanism for varying the distance between these pegs 35, 36 between a distance (b) corresponding to the distance between each pair of a front bobbin hanger 12 and a back bobbin hanger 12, facing each other in the creel, and a distance (a) corresponding to the distance between two adjacent bobbin hangers 15 on the carriage 14 of the supply rail 13, a mechanism 60 for actuating the telescopic mechanism of the peg unit 40 so that the axial distance between pegs 35, 36 can be changed, a lifting mechanism 70 which is capable of lifting the peg unit 40 between a position where the pair of pegs is positioned immediately below the full packaged roving bobbins suspended by the corresponding bobbin hangers 15 of the supply rail 13 and a position where the pair of pegs 35, 36 is positioned immediately below the bobbin hangers 15 without roving bobbins on the supply rail 13, after the axial distance between two pegs 35, 36 has been changed to coincide with axial distance between the corresponding two bobbin hangers. As illustrated in Figs. 1 and 2, the lifting device 70 is mounted on a support plate 72 provided within the body 31 of the roving bobbin exchanging apparatus 30. A first motor 71 for the lifting device 70 is secured to the lower side of he supporting plate 72, a lower pillar bracket 73a is secured to the upper surface of the supporting plage 72, an upper pillar bracket 73b is secured to the upper plate of the body 31, two pillars 75a and 75b are extended vertically between the lower pillar bracket 73a and the upper pillar bracket 73b, and a slider 77 is mounted on the two pillars 75a and 75b for sliding movement along the two pillars 75a and 75b. A chain 76 is extended between a sprocket wheel 74a secured to the output shaft of the first motor 71 and a sprocket wheel 74b rotatably mounted on a pin secured to the upper pillar brack et 73b. The chain 76 is securedly connected to the slider 77 by chain holders 78a and 78b. Two supporting rods 79a and 79b are secured to the slider 77 in a vertical posture, and a supporting member 96 for supporting the peg unit 40 is secured to the respective upper ends of the supporting rods 79a and 79b. Accordingly, when the first motor 71 is actuated, the slider 77 is displaced vertically by the chain 76, whereby the peg unit supporting member 96 supporting the peg unit 40 can be moved vertically. Referring to Fig. 3 and 4, a hollow shaft 94 is journaled in bearings 97a and 97b on the supporting member 96, and a motor 91 of a displacing device 90 is secured to the supporting member 96. A driving shaft 64 extended through the hollow shaft 94 has an upper end which is rotatably supported in bearing 66a on the hollow shaft 94 and a lower end which is rotatably supported in a bearing 66b on a lower bracket 93 secured to the lower end of the hollow shaft 94. A second motor 81 for the mechanism for actuating the telescopic mechanism 60 is suspended rigidly from the lower bracket 93 by bolts. A driving gear 68 secured to an output shaft 67 of the second motor 81 and a gear 69 secured to the lower end of the driving shaft 64 are meshed, and a peg unit driving gear 65 is secured to the upper end of the driving shaft 64. A gear 98 having a large diameter is formed integrally with the upper end portion of the hollow shaft 94, and a slide base 41 is fastened with bolt 98a to the gear 98. As shown in Figs. 3 and 4, the peg unit 40 is provided with the slide base 41 secured to the hollow shaft 94, a first slider 42 which slides on the slide base 41, and a second slider 43 which slides on the first slider 42. The slide base 41 has a U-shaped cross-section, and the opposite longitudinal ends (the right and left ends as shown in Fig. 3) of the slide base 41 are bent outward to form lugs 41a. First rods 44 are fastened to the upper surfaces of the lugs 41a with bolts, and one of the bolts fastening the first rods 44 to the lugs 41a projects upward to serve also as a stopper pin 57. A second rack 52 is secured through collars 52a and 52b (Fig. 5) to the upper surface of the slide base 41. The first slider 42, as well as the slide base 41, has a U-shaped cross-section, and second rods 45 are fastened to lugs formed in the first slider 42 at the opposite longitudinal ends thereof with bolts. Bearing parts 47 projecting from the opposite sides of the first slider 41 are slidably engaged with the first rods 44 therethrough. A first rack 51 engaging the gear 65 of the driving shaft is fastened to the lower surface of the first slider 42, and a pinion 54 is supported rotatably on the upper surface of the first slider 42. The pinion 54 engages with the second rack 52 and a third rack 53 secured to the lower surface of the second slider 43. An elongated slot 42a is formed in the bottom wall of the first slider 42 to enable the second rack 52 to move without interfering with the first slider 42. The second slider 43 also has a U-shaped cross-section. Bearing parts 48 project from the opposite sides of the second slider 43 slidably engaged with the second rods 45 therethrough. The peg 35 is rigidly mounted on the front end of the second slider 43, and the peg 36 is mounted slidably on a third rod 46 secured to the upper surface of the bottom wall of the second slider 43. As shown in Figs. 6, 7(A), and 7(B), a wire drum 58 disposed within the second slider 43 is urged in a winding direction to wind a wire 61 by a spiral spring 59. The wire 61 is extended via a guide roller 62. One free end thereof is connected to a hook 61a secured to the front side of the peg 36. Accordingly, the peg 36, which is slidable along the third rod 46, is pulled forward and the sliding motion of the peg 36 is stopped by contact with a stopper 63 secured to the second slider 43, which functions as a seat for the third rod 46, so that the position of the peg 36 is regulated. In this condition, the distance between the pegs 35 and 36 is identical to the distance (a) between the adjacent two bobbin hanger 15 on the supply rail 13. An engaging member 56 is secured to the side surface of the peg 36 so as to project into a space between a bearing part 47 of the first slider 42 and a bearing part 48 of the second slider 43. Thus, the first slider 42 and second slider 43 of the peg unit 40 can be are advanced and retracted telescopically. That is, when the second motor 81 is actuated, the rotative power of the second motor 81 is transmitted through the gears 68 and 69 to the driving shaft 64 to rotate the driving gear 65. Consequently, the first slider 42 is advanced by sliding along the slide base 41, and the pinion 54 supported on the first slider 42 engaging the second rack 52 is caused to rotate while moving together with the first slider 42. Since the pinion 54 rotates about the center thereof while moving linearly together with the first slider 42, the circumferential speed of the pinion 54 is twice the linear speed of the first slider 42, and since the third rack 53 secured to the second slider 43 engages the pinion 54, the second slider 43 slides forward on the first slider 42 at a linear speed twice the linear speed of the first slider 42. While the first slider 42 and the second slider 43 are thus advanced, the engaging member 56 secured to the peg 36 comes into contact with the stopper pin 57 so that a further advance of the peg 36 is stopped. The first slider 42 and the second slider 43 are advanced further while the peg 36 moves backward relative to the second slider 43 against the resilient force of the spiral spring 58. When the first slider 42 and the second slider 43 arrive, respectively, at the front end of their forward motion, as indicated by imaginary lines in Figs. 3 and 5, the distance (b) between the pegs 35 and 36 becomes equal to the distance (B) between a front bobbin hanger and a back bobbin hanger facing this front bobbin hanger, on the creel of the spinning frame (Fig. 9). During retraction, the peg 36 comes into contact with the stopper 63 of the second slider 43 and, thereafter, the first slider 42 and the second slider 43 retract, respectively, to standing positions as indicated by lines in Fig. 3, while the pegs 35 and 36 are maintained with the distance (a) therebetween. The control of the relative movement of the peg 36 to the peg 35 so as to change the axial distance between the pegs 35 and 36 explained with reference to the embodiment shown in Figs. 3, 6A, 6B, 7A, and 7B can be carried out by the following modification thereof as shown in Figs. 8A to 8C. An engaging member 101 is bolted through a collar 102 to the side surface of the peg 36 as shown in Figs. 8A to 8C. As shown in Fig. 8B, a stopping surface 103 with which the collar 102 is brought into contact is formed above the bearing part 47 on one of the side walls of the first slider 42. Then, while the first slider 42 and the second slider 43 are advanced telescopically, the engaging member 101 bolted to the peg 36 comes into contact with the stopper pin 57 to control the motion of the peg 36 and, thereafter, the distance between the pegs 35 and 36 becomes equal to the distance (b) at the forward end of the advanced movement of the first slider 42 and the second slider 43. During retraction of these sliders, similar to the mode during the advance thereof, since the second slider 43 is retracted at a linear speed twice that of the first slider 42, the collar 102 secured to the peg 36 comes into contact with the stopping surface 103 of the first slider 42, so that the distance between the pegs 35 and 36 is gradually decreased in accordance with the rearward motion of the first slider 42 and the second slider 43, and the distance between the pegs 35 and 36 becomes equal to the distance (a) upon the arrival of the first slider 42 and the second slider 43 at the respective ends of their rearward displacing motion, which are their standby positions, respectively. Referring to Fig. 4, the displacing device 90 utilized in this embodiment is provided with a gear 99 engaging the large gear 98 secured to the hollow shaft 94 and keyed to an output shaft 19a of the motor 91 (hereinafter referred to as "third motor"), mounted on the supporting member 96, for driving the peg unit 40. The output shaft 91a of the third motor 91 is rotated in the normal direction or in the reverse direction to turn the peg unit 40 on the hollow shaft 94, so that the peg unit 40 can be directed in desired directions. The roving bobbin exchanging method carried out by the above-mentioned apparatus 30 will be described hereinafter with reference to schematic plans views shown in Figs. 9 and 10(A) to 10(H). As shown in Fig. 9, pairs of front and back half exhausted roving bobbins 120F and 120B and pairs of front and back exhausted roving bobbins 2F and 2B are suspended alternately on the bobbin hangers 12 on the creel of the spinning frame, while at least two empty bobbin hangers 15 and a plurality of pairs of two adjacent bobbin hangers holding full packaged roving bobbins are carried to the predetermined position on the supply rail facing the above-mentioned creel of the spinning frame. The number of such bobbin hangers holding full packaged rovin bobbin is identical to the number of above-mentioned pairs of bobbin hangers in the creel of one side in the spinning frame. The pair of full packaged roving bobbins suspended by each pair of two adjacent bobbin hangers on the supply rail 13 is hereinafter referred to as 1F and 1B, as shown in Fig. 9. The roving bobbin exchanging apparatus 30 traveling along the spinning frame from the direction of an arrow (Fig. 9) stops at a predetermined first position where the peg unit 40 faces the first pair of exhausted roving bobbins 2F and 2B (Figs. 1 and 10(A)). The slider-mechanism is then actuated to advance the pegs 35 and 36 of the peg unit 40, whereby the distance between the pegs 35 and 36 increases in accordance with the forward motion of the pegs 35 and 36. Finally, the peg 35 reaches a position immediately below the exhausted roving bobbin 2B and the peg 36 reaches a position immediately below the exhausted roving bobbin 2F (Fig. 10(B)). Subsequently, the lifting mechanism 70 is actuated to raise the peg unit 40 to remove the exhausted roving bobbins 2F and 2B from the respective bobbin hangers 12 on the creel of the spinning frame, and the peg unit 40 is then lowered. Then, the pegs 35 and 36 are retracted to the respective standby positions in the peg unit 40 (Fig. 10(C)). The distance between the pegs 35 and 36 decreases in accordance with the retracting motion of the pegs 35 and 36. Then, the displacing unit 90 is acutated to turn the peg unit 40 by an angle of 90° so that the peg unit 40 extends along the longitundunal direciton of the supply rail 13, and at the same time, the pegs 35 and 36 are advanced slightly to a position immediately below the empty bobbin hangers 15 (Fig. 10(D)). The distance between the pegs 35 and 36 remains unchanged, because the pegs 35 and 36 are advanced by only a small distance. Then, the peg unit 40 is raised by the lifting mechanism 70 so that the exhausted roving bobbins 2F and 2B supported on the pegs 35 and 36 are transferred to the corresponding empty bobbin hangers 15 of the supply rail 13, then the peg unit 40 is lowered. Then, the peg unit 40 is retracted slightly and, at the same time, the peg unit 40 is turned counterclockwise by an angle of 180°, as indicated by an arrow (Fig. 10(E)), by the displacing unit. The pegs 35 and 36 of the peg unit 40 are then displaced slightly forward to a position immediately below the corresponding full roving bobbins 1F and 1B, respectively. Subsequently, the lifting mechanism 70 is actuated to raise the peg unit 40 to remove the full roving bobbins 1F and 1B from the respective bobbin hangers 15, and then the peg unit 40 is lowered in a condition such that the full roving bobbins 1F and 1B are supported by the corresponding pegs 35 and 36, respect ively (Fig. 10(E)). The peg unit 40 is turned clockwise as indicated by an arrow by an angle of 90° after retracting the pegs 35 and 36 slightly (Fig. 10(F)), and then the pegs 35 and 36 are advanced so that the distance therebetween is increased such that the full roving bobbins 2F and 2B come to positions immediately below the empty bobbin hangers 12 on the creel of the spinning frame from which the exhausted roving bobbins 2F and 2B have just been removed. The lifting mechanism 70 is actuated to raise the peg unit 40 to the full package roving bobbins 1F and 1B, which are supported by the respective pegs 35 and 36, so that these full packaged roving bobbins are transferred to the corresponding bobbin hangers 12 (Fig. 10(G)). The peg unit 40 is then lowered and retracted to return the peg unit 40 to the standby position (Fig. 10(H). The above-mentioned unit operation for carrying out the roving bobbin exchanging operation is stepwisely applied to the pairs of bobbin hangers of the front and back row, suspending exhausted roving bobbins, wherein, in each pair, one of the exhausted roving bobbins is suspended by a front bobbin hanger and the other by a back bobbin hanger, in facing condition, from one end of the spindle alignment to the other end, so that a series of roving bobbin exchanging operations is completed for one side of the spinning frame. A second embodiment of the present invention will be described hereinafter. The roving bobbin exchanging apparatus in the second embodiment is applied to exchanging roving bobbins on a spinning frame provided with two supply rails extended in front of the front row of bobbin hangers. In this embodiment, as shown in Fig. 13, the same number of pairs of front and back full packaged roving bobbins as pairs of exhausted roving bobbins suspended by the bobbin hangers on the creel of the spinning frame are suspended by the respective pairs of bobbin hangers carried to the working positions of the two supply rail. The alignment of each pair of full packaged roving bobbins 12 of the supply rails coincides to the alignment of corresponding pairs of exhausted roving bobbins 2B, 2F in the creel of the spinning frame. Therefore, the axial distance between two adjacent exhausted roving bobbins in the front row of the bobbin hanger alignment or in the back row of the bobbin hanger alignment is identical to the axial distance between two adjacent full packaged roving bobbins in the front supply rail or in the back supply rail. Only the first pair of exhausted roving bobbins 2B and 2F faces a first pair of bobbin hangers 15, which are facing each other, on the two rows of supply rails. This first pair of bobbin hangers 15 does not hold roving bobbins, that is, these bobbin hangers are so-called empty bobbin hangers. When the roving bobbin exchanging operation is started, the roving bobbin exchanging apparatus 30, which is capable of traveling along the spinning frame, is first stopped at a position such that the pegs 35 and 36 of the peg unit 40 thereof are located immediately below the above-mentioned pair of empty bobbin hanger 15, and thereafter the successive operation steps involved in the unit roving bobbin exchanging operation is carried out. After completion of the above-mentioned first unit roving bobbin exchanging operation, the apparatus 30 is displaced to the next adjacent position to carry out the second unit operation, and such successive unit operations are carried out form the one end side of the spinning frame to the other end side thereof. The roving bobbin exchanging apparatus 30 of the second embodiment is provided with a peg unit 40 comprising a slider mechanism to which a pair of pegs 35, 36 is mounted such as to allow changing of the axial distance thereof, a telescopic mechanism to actuate the slider mechanism so that the axial distance between the above-mentioned pegs 35, 36 is varied between a distance corresponding to the distance (B) between the pair of front and back bobbin hangers on the cree l and a distance corresponding to the distance (A) between the pair of bobbin hangers of the supply rail, and a mechanism 60 for actuating the telescopic mechanism. This apparatus is further provided with a lifting device 70 vertically displacing the peg unit 40. Those constitutional elements of the second embodiment may be understood as identical to those of the first embodiment mentioned above. However, since the displacing mechanism 100, which displaces the peg unit 40 to positions immediately below the empty bobbin hangers of the supply rail or immediately below the full packaged roving bobbins of the supply rail, is different from the corresponding mechanism of the first embodiment, the construction and function of the displacing mechanism 100 is hereinafter explained. As shown in Fig. 11, in the peg unit 40, two pairs of connecting members 113 are secured to the lower surface of the bottom wall of the slide base 41 of the peg unit 40 at the front and back thereof, and pairs of supporting shafts 107 are rigidly mounted on the front and back surfaces of the slider 77 at the right and left sides thereof. Each of the supporting rods 105a, 105b, 106a, and 106b has an identical length and is turnably connected at both end portions thereof by the corresponding supporting shafts 107 and the pins 108 of the corresponding connecting member 113. Thus, the four supporting rods 105a, 105b, 106a, and 106b, the slide base 41, and the slider 77 constitute a pair of parallel linkages for supporting the peg unit 40 for swing motion in the longitudinal direction of the spinning frame. A fourth motor 110 for driving the displacing device is mounted on a motor base 109 secured to the back surface (the left surface as viewed in Fig. 11) of the slider 77. A swing lever 111 having a slot is secured to the output shaft of the fourth motor 110, and a pin 112 secured to the supporting rod 106a is received in the slot of the swing lever 111. The output shaft of the fourth motor 110 is rotated in the normal or reverse direction to swing the peg unit 40 within a predetermined range. Since the slide base 41 of the peg unit 40 of the second embodiment is supported by the four supporting rods 105a, 105b, 106a, and 106b, the roving bobbin exchanging apparatus in the second embodiment does not need the hollow shaft 94 supported on the supporting member 96 of the first embodiment. Accordingly, the second motor 81 for the slider-actuating device can be disposed directly on the bottom surface of the slide base 41, and the drive gear 65 for actuating the telescopic mechanism can be rigidly mounted on the output shaft of the second motor. The roving bobbin exchanging procedures for the roving bobbin exchanging apparatus 30 in the second embodiment are similar to those carried out by the roving bobbin exchanging apparatus 30 in the first embodiment. In the roving bobbin exchanging operation of the roving bobbin exchanging apparatus 30 in the second embodiment, as described hereinbefore, the pegs 35 and 36 are stopped directly below the corresponding pair of bobbin hangers 15 on the supply rails (Fig. 14(A)), the peg unit is advanced to remove the exhausted roving bobbins 2F and 2B (Fig. 14(B)), the pegs 35 and 36 are returned to the standby positions, and then the exhausted roving bobbins are suspended by the empty bobbin hangers 15 on the supply rails (Fig. 14(C)). Then, the displacing device 100 swings the peg unit 40 to a position where the pegs 35 and 36 are located immediately below the full packaged roving bobbins 1F, 1b suspended by the corresponding bobbin hangers of the supply rails. Then the full packaged roving bobbins 1F and 1B are removed from these bobbin hangers of the supply rails (Fig. 14(D)), the peg unit 40 is returned to the standby position (Fig. 14(E)), the peg unit 40 is advanced to transfer the full packaged roving bobbins 1F and 1B on the bobbin hangers 12 from which the exhausted roving bobbins 2F and 2B have just been removed (Fig. 14(F)), and then the peg unit 40 is return ed to the standby position (Fig. 14(G)), to complete one cycle of the roving bobbin exchanging operation. The roving bobbin exchanging apparatus 30 is moved intermittently along the longitudinal direction of the spinning frame by a step corresponding to the longitudinal axial intervals c, between adjacent two pairs of bobbin hangers on the creel of the spinning frame, which is half the step of the movement of the roving bobbin exhanging apparatus in the first embodiedment, to repeat the cycle of roving bobbin exchanging operations sequentially. In the above-mentioned first embodiments of the present invention, two additional bobbin hangers 15 not holding roving bobbins, in addition to the bobbin hangers holding full packaged roving bobbins, which number is identical to half the number of spindles of each side of the spinning frame, are mounted on each bobbin carriage on the supply rail 13. However, if the above-mentioned bobbin carriage utilized for the first embodiment of the present invention is utilized for changing the roving bobbins in a long spinning frame provided with double the number of spindles of a conventional spinning frame, modification of the first embodiment of the present invention must be considered. This is because, in this case, it is necessary to use two connected bobbin carriages for supplying full packaged roving bobbins to this long spinning frame. Therefore, a bobbin carriage provided with two bobbin hangers not holding a roving bobbin at the middle portion thereof must be used. Accordingly, the above-mentioned roving bobbin exchanging apparatus disclosed as the first embodiment of the present invention cannot be used. To solve this problem, the following modification of the first embodiment was developed as explained hereinafter. That is, as shown by imaginary lines in Fig. 2, a pair of bobbin supporting members 150 is mounted vertically on the main body of the roving bobbin exhanging apparatus 30, so as to temporarily hold two full packaged roving bobbins (or a pair of front or back exhausted roving bobbins facing each other on the creel of the spinning frame) which are first exchanged, and then the roving bobbin exchanging operation is carried out in the same way as explained in the disclosure of the first embodiment. Further as the last operation, the two full packaged roving bobbins (or exhausted roving bobbins) which are held by the above-mentioned bobbin supporting members 150 are displaced to the corresponding bobbin hangers 12 of the creel of the spinning frame (or the corresponding bobbin hangers 15 of the supply rail 13) respectively. In this case, for each unit of the bobbin carriage explained in the first embodiment of the present invention, it is necessary to omit the two bobbin hangers not holding empty roving bobbins. For example, in the above-mentioned first embodiment of the present invention, as shown by the imaginary line in Fig. 2 and as shown in Fig. 15, the bobbin supporting member 150 is secured to a pillar 151 rigidly mounted on the main body of the apparatus 30. This bobbin supporting member 150 and the pillar 151 are positioned so that they do not disturb the motion of the peg unit 40 mentioned in the disclosure of the first embodiment of the present invention. In this embodiment, the bobbin supporting member 150 is formed by a pair of U-shaped bobbin holding portions 150a, which open toward the turning center of the peg unit 40 with an intervening distance between their opening centers which is identical to the central distance between two adjacent bobbin hangers 15 of the supply rail 13, and by an arc-shaped portion which connects the above-mentioned bobbin holding portions 150a. Each flange of the roving bobbins can be engaged by the respective bobbin holding portions 150a. As the above-mentioned bobbin supporting member 150, a member such as a usual bobbin hanger of a member for gripping the roving bobbin can be utilized. In the above-mentioned second embodiment of the present invention, a bobbin supporting member such as t he above-mentioned bobbin supporting member 150 can be also utilized if the bobbin exchanging apparatus is used for a long spinning frame. In the above-mentioned embodiment, of course, the first motor 71 for vertically moving the peg unit 40 and the second motor 81 for displacing the peg unit 40 can be actuated simultaneously when vertically moving the peg unit 40 for receiving the exhausted roving bobbins 2F, 2B or the full packaged roving bobbins 1F, 1B on the pegs 35 and 36, to reduce the time necessary for carrying out the roving bobbin exchanging operation. The lifting mechanism 70, the mechanism for actuating the telescopic mechanism 60, and the displacing devices 90 and 100 for moving the peg unit 40 can be driven by hydraulic cylinders instead of motors. When pneumatic actuators are employed instead of motors, the roving bobbin exchanging apparatus can be designed with a compact construction when a rodless pneumatic cylinder is employed for driving the mechanism for actuating the telescopic mechanism 60, and a rotary actuator is employed for driving the displacing device 90. Furthermore, in the first embodiment, although the peg unit 40 is advanced slightly and retracted slightly to position the pegs 35, 36 of the peg unit 40 immediately below the empty bobbin hangers on the supply rail 13 and immediately below the full packaged roving bobbins on the supply rail 13, respectively, in order to position the roving bobbin exchanging apparatus as close as possible to the spinning frame, the operations for slightly advancing and slightly retracting the peg unit 40 can be omitted when the supply rail 13 and the roving bobbin exchanging apparatus 30 are moved away from the spinning frames so that the peg unit 40 will not interfere with the spinning frame when turning the peg unit 40 by an angle of 90° or 180°, and the pegs 35 and 36 are positioned on the radius of rotation. It is not essential to make coincide the axial alignment of a pair of front and back exhausted roving bobbins facing each other in the creel to the axial alignment of two full packaged roving bobbins suspended by a bobbin hanger of a front supply rail and a bobbin hanger of a back supply rail, facing each other. Although not shown in the drawings illustrating the above-mentioned embodiments, it is preferable to connect the pegs 35 and 36 with a compact motor or motors and to support the pegs 35 and 36 rotatably in order to take-up residual rovings of the exhausted roving bobbins in the roving bobbin exchanging operation after the completion of a roving piecing operation. For such a purpose, in the embodiments described herein, the slider base 41, the first slider 42, and the second slider 43 are formed as members each having a U-shaped cross-section, and the second slider 43 is adapted to accommodate a compact motor or motors. However, the slide base 41, the first slider 42, and the second slider 43 may be formed in the shape of a flat plate, and the slide base 41, the first slider 42, and the second slider 43 may be dovetailed in an ordinary fashion so as to be able to slide relative to each other, when only the roving exchanging function is required for the roving bobbin exchanging apparatus. Still further, the telescopic mechanism is not limited to that of the above-mentioned embodiment, but, since the overhang length becomes large when the sliders are moved up to the position where the pegs are immediately below the corresponding pair of front and back exhausted roving bobbins on the creel of the spinning frame, it is practically advantageous to utilize the first slider 42 and the second slider 43, and to make the second slider 43 advance and retract at a speed twice the speed of the first slider 42. As apparent from the above-mentioned description, according to the present invention, since a peg unit including a pair of pegs mounted on sliders and capable of being displaced forward or backward by the telescopic mechanism in a condition such that one peg is secured to the corresponding slider while the other peg is slidable, and further, the distance between these pegs can be changed during the above-mentioned forward and backward displacing motion of the sliders so that the above-mentioned distance becomes identical to the axial distance between two bobbin hangers facing each other in the creel of the spinning frame, at the front terminal position of the forward motion of the slider, while the above-mentioned distance becomes identical to the distance between two adjacent bobbin hangers on the supply rail or two facing bobbin hangers on two supply rails at the back terminal position of the backward motion of slider, these pegs can be positioned immediately below the corresponding empty bobbin hangers of a supply rail or rails and positioned immediately below the corresponding full packaged roving bobbin of the supply rail or rails. Accordingly, the roving bobbin exchanging operation can be carried out in very preferable condition without trouble. Furthermore, since the component devices of the roving bobbin exchanging apparatus can be assembled in a small space, the roving bobbin exchanging apparatus can incorporate a roving piecing apparatus which is utilized for automatically piecing the roving from a full roving bobbin and the end portion of the roving from an exhausted roving bobbin while carrying out the normal spinning operation.

Claims: 1. A method for exchanging pairs of roving bobbins, each pair of roving bobbins being suspended by respective front and back bobbin hangers, mounted on a creel of a spinning frame in a facing condition, for full packaged roving bobbins suspended by bobbin hangers of a supply rail extended in front of and above said creel, by utilizing a peg unit provided with a pair of pegs, wherein a unit bobbin exchanging operation applied to each pair of said front roving bobbin and said back roving bobbin facing each other is intermittently but successively carried out along a spindle alignment of said spinning frame from one side to the other side when said roving bobbins in said creel become almost exhausted, said unit operation comprising (1) taking off said pair of almost exhausted roving bobbins suspended by corresponding bobbin hangers of said creel by means of said pair of pegs (2) displacing said pegs holding almost exhausted roving bobbins to corresponding positions immediately below prepared empty bobbin hangers of said supply rail without roving bobbins, then hanging said almost exhausted roving bobbins on said empty bobbin hangers by displacing said pegs (3) displacing said pegs to positions immediately below corresponding two adjacent bobbin hangers of said supply rail holding full packaged roving bobbins, and then mounting said full packaged roving bobbins on said pegs by displacing said pegs, (4) displacing said pegs, each peg holding said full packaged roving bobbins, to positions immediately below the corresponding bobbin hangers of said creel from which said almost exhausted roving bobbins have been taken off by said first step (1), then hanging said full package roving bobbins on said bobbin hangers from which said almost exhausted roving bobbins have been taken off, of said creel, by displacing said pegs upward. 2. A method for exchanging pairs of roving bobbins in a spinning frame according to claim 1, further utilizing a pair of additional bobbin hangers arranged at a position right upstream of an alignment of bobbin hangers and suspending full packaged roving bobbins on said supply rail, wherein said additional bobbin hangers are utilized as said prepared empty bobbin hangers to carry out first unit operation of said roving bobbin exhanging operation. 3. A method for exchanging pairs of roving bobbins in a spinning frame according to claim 1, wherein the first and the last unit operation of said roving bobbin exchanging operation are modified by adopting steps of temporarily reservi ng two roving bobbins, in said first unit operation, after said first step operation, said almost exhausted roving bobbins are temporarily reserved at predetermined positions so that said pegs become free to receive full package roving bobbins, then said pegs are displaced to the positions immediately below corresponding full packaged roving bobbins suspended by two adjacent bobbin hangers of said supply rail, then said full packaged roving bobbins are transferred to corresponding pegs, after completion of the last unit operation, said pegs are displaced to corresponding positions facing said almost exhausted roving bobbins reserved temporarily by said first step operation and said reserved roving bobbins are mounted on said pegs, thereafter said temporarily reserved almost exhausted roving bobbins are displaced toward the last pair of bobbin hangers of said supply rail from which said full packaged roving bobbins have been taken off and then caught by said bobbin hangers by displacing said pegs upward. 4. A method for exchanging pairs of roving bobbins in a spinning frame according to claim 1, wherein, during the displacing motion of said pegs, an axial distance of said two pegs is charged from a distance identical to an axial distance of a front bobbin hanger and a back bobbin hanger facing each other in said creel to a distance identical to an axial distance between two adjacent bobbin hangers of said supply rail, and vice versa, so that the axial alignment of each roving bobbin carried to a position immediately below a corresponding bobbin hanger of said creel or of said supply rail coincides to the axial alignment of said bobbin hanger. 5. A method for exchanging pairs of roving bobbins in a spinning frame according to claim 1, wherein, in any operation step of each unit operation of exchanging roving bobbins, each roving bobbin suspended by a bobbin hanger is taken off by displacing said peg upward and then downward while engaging in a bottom aperture thereof, each roving bobbin mounted on said peg is transferred to a bobbin hanger from said peg by displacing said peg upward and then downward. 6. A method for exchanging pairs of roving bobbins in a spinning frame according to claim 1, wherein the first and the last unit operations of said roving bobbin exchanging operation are modified by adopting a step of temporarily reserving roving bobbins, in said first unit operation, two pairs of full packaged roving bobbins are taken off from the first pair of bobbin hangers of said supply rail so that said empty bobbin hangers are prepared on said supply rail, said first step to said fourth step operations are carried out, and thereafter said temporarily reserved full packaged roving bobbins are transferred to the last pair of a front bobbin hanger and a back bobbin hanger from which almost exhausted roving bobbins have been taken off, by displacing said pegs. 7. An apparatus for exchanging pairs of roving bobbin for full packaged roving bobbins in a spinning frame, said apparatus being capable of displacing along a spindle alignment of each side of said spinning frame and capable of stopping at predetermined positions facing corresponding bobbin hangers of a creel of said spinning frame, wherein said bobbin hangers are arranged in two rows in a condition wherein each pair of bobbin hangers is formed by a bobbin hanger of said front row and a bobbin hanger of back row facing each other, and being capable of exchanging pairs of roving bobbins, which are almost exhausted, suspended by bobbin hangers of front row and bobbin hangers of a back row in said creel, for full packaged roving bobbins suspended by bobbin hangers of said supply rail being arranged along said spindle alignment at a position in front and above said creel, comprising a peg unit provided with a plurality of sliding members, a telescopic mechanism for relatively displacing said sliding members in forward or rearward directions, a pair of pegs mounted on said peg unit in a co ndition enabling of changing of an axial distance therebetween during a forward or rearward displacing motion of said sliding members in such a condition that at the end of said forward displacing motion of said sliding members, said axial distance becomes a distance identical to an axial distance between said front bobbin hanger and said back bobbin hanger forming a pair facing each other in said creel, while at the end of said backward motion of said sliding members, said axial distance becomes a distance identical to an axial distance between two adjacent bobbin hangers of said supply rail; a device for actuating said telescopic mechanism to create said forward and rearward displacing motion of said sliding members; a device for lifting said peg unit; and a device for displacing said peg unit to positions of said pegs immediately below corresponding bobbin hangers of said creel and also immediately below corresponding bobbin hangers of said supply rail. 8. An apparatus for exchanging pairs of roving bobbins for full packaged roving bobbins in a spinning frame according to claim 7, wherein said peg unit is provided with a slide base, said sliding members comprises a first slider and a second slider, said first slider is capable of sliding on said slide base of said peg unit, said second slider is capable of sliding on said first slider, one of said pegs is secured on a front end portion of said second slider, the other peg is slidably mounted on said second slider, said second slider is provided with a stopper while said slidable peg is provided with an engaging member, a stopper pin is secured so said slide base, whereby, when said second slider reaches an end of the backward displacing motion thereof, said slidable peg is in contact with said stopper of said second slider so that an axial distance between said two pegs becomes a distance identical to two adjacent bobbin hangers of said supply rail, on the other hand, during the forward displacing motion of said second slider, when said engaging member of said slidable peg is in contact with said stopper pin of said slide base, and thereafter said slider reaches to an end portion of its forward displacing motion thereof while maintaining the contact between said engaging member and said stopper pin, an axial distance between said two pegs becomes to a distance identical to an axial distance between a front bobbin hanger and a back bobbin hanger facing each other in said creel. 9. An apparatus for exchanging pairs of roving bobbins by full packaged roving bobbins in a spinning frame according to claim 7, wherein said peg unit is provided with a slide base, said sliding members comprises a first slider and a second slider, said first slider is capable of sliding on said slide base of said peg unit, said second slider is capable of sliding on said first slider, some of said pegs is secured on a front end portion of said second slider, the other peg is slidably mounted on said second slider, said first slider is provided with a stopper while said slidable peg is provided with an engaging member, and a stopper pin is secured to said slide base, whereby, when said second slider reaches the end of its backward displacing motion, said slidable peg is in contact with said stopper of said first slider so that an axial distance between two pegs is maintained at a distance identical to an axial distance between two adjacent bobbin hangers of said supply rail, and on the other hand said engaging member of said slidable peg is in contacts with said stopper pin of said slide base in the forward displacing motion of said second slider, and when said second slider reaches the end of said forward displacing motion of said second stopper while said contacting is maintained between said engaging member with said stopper pin, an axial distance between said two pegs becomes a distance identical to an axial distance between a front bobbin hanger and a back bobbin hanger facing each other in said creel. 10. An apparatus fo r exchanging pairs of roving bobbins for full packaged roving bobbins in a spinning frame according to claim 7, wherein said telescopic mechanism comprises a wheel gear rotatably mounted on an axis secured to said slide base, and a first rack rigidly mounted on said slider and meshing with said wheel gear, a pinion rotatably mounted on an axis mounted on a first slider, a second rack rigidly mounted on said slide base and meshing with one side of said pinion, a third rack rigidly mounted on said second slider and meshing with the other side of said pinion, said actuating device is provided with a driving motor to actuate said telescopic mechanism, whereby said driving motor of said actuating device is driven, said first slider starts its forward displacing motion so that said second slider is capable of displacing forward with a forwarding speed which is double the forwarding speed of said first slider. 11. An apparatus for exchanging pairs of roving bobbins for full packaged roving bobbins in a spinning frame according to claim 7, wherein said displacing device comprises a first gear rigidly mounted on a bottom surface of said slide base of said peg unit for turning said peg unit, a second gear meshing with said first gear, a driving motor for driving said second gear being secured on a shaft of said motor, whereby when said driving motor is actuated, said displacing device is actuated to turn said peg unit. 12. An apparatus for exchanging pairs of roving bobbins for full packaged roving bobbins in a spinning frame according to claim 7, wherein said lifting device is provided with a lifting slider for lifting said peg unit, said lifting slider is provided with a swing lever, said displacing device is provided with at least two supporting rods, one end of each supporting rod is connected to a bottom surface portion of said slide base of said peg unit by a pin, while the other end of each supporting rod is connected by a pin to said lifting slider of said lifting device, and said swing lever of said lifting slider is connected to said support rod, whereby said peg unit is capable of swinging in two directions opposite each other. 13. An apparatus for exchanging pairs of roving bobbins for full packaged roving bobbins in a spinning frame according to claim 7, further provided with a pair of roving bobbin holding members for temporarily reserving a first pair of almost exhausted roving bobbins or full packaged roving bobbins. 14. An apparatus for exchanging pairs of roving bobbins for full packaged roving bobbins in a spinning frame according to claim 13, wherein an axial distance between said two roving bobbin holding members is identical to the axial distance of two adjacent bobbin hangers of said supply rail.

Inventors: HORIBE, TATUTAKE, KAWASAKI, YOSHIO, SASAKI, KENJI, YAMADA, KAZUO
Applicants: HOWA MACHINERY LIMITED
Application year: 1987
Main classification: D01H9
IPC codes: B65H67, D01H9