Method and apparatus for tying one or more articles

Abstract: A tying wire (a) is puled out from a continuous stock. It is then bent to form a U-shaped fold of an appropriate length. The U-shaped loop (b) of the tying wire is wound around an overlapped portion to be tied of an article or articles (E). A front end of the U-shaped fold is wound around the other end (c) by a rotatable hook (G), thus finally twisting both ends. The tying wire (a) is cut at a rear end an appropriate timing. The apparatus for tying is made up of a mechanism for forming a U-shaped loop of the tying wire, a mechanism for guiding the U-shaped loop to wind it around an external surface of a portion to be tied of the article or articles, a mechanism for twisting the closed end and the other end of the U-shaped loop, and a mechanism for cutting the tying wire at an appropriate timing to an appropriate length.

Description: The present invention relates to a method for tying one or more articles such as reinforcing bars for construction or structural purposes, flexible containers such as bags, or the like, and to an apparatus for carrying out said method. There is known a method for tying one or more articles, particularly an overlapped portion of articles, such as reinforcing bars for construction or structural purposes, or the like, in which a worker for arranging or placing in position reinforcing bars, winds a single piece of annealed steel wire of a predetermined length around the overlapped portion of the reinforcing bars in situ or on a construction site. It is also known to use as a tying wire a U-shaped fold or loop of an annealed steel wire which is already cut into a predetermined length. In such a case, a hooked end of a twisting tool is engaged with a closed end of the U-shaped fold. The twisting tool is then manually twisted or turned several times to thereby twist together the front end and the rear end of the U-shaped fold. In the above-described conventional method of manually twisting a single piece of steel wire around one or more articles, particularly around the overlapped portion for tying, it is necessary to strongly hold both ends of the steel wire before winding it around one or more articles, particularly around the overlapped portion. This manual work is troublesome and a mechanical means for holding both ends was difficult to devise. If this strongly held portion gets loosened, it becomes impossible to twist the steel wire as well as to firmly and immovably tie the overlapped portion together. If the twisting is carried out excessively to ensure the tying of the articles, the steel wire may give rise to rupture. Further, in the above-described conventional method it is normal practice to hold both ends of the tying wire to be twisted with one hand and insert the hooked end of the twisting tool into the front end of the loop with the other hand, thereafter rotating the twisting tool on the construction site. This job requires a high degree of skill, and it has to be repeated many times, especially in view of tying, for example, all of the overlapped portions of the reinforcing bars on one construction site. This repetition is hard work for the worker, and the time to be spent for this particular job becomes long. As a result, the efficiency of the tying work is lowered. A hand-held apparatus is known from the JP-A-63-191719 for binding articles wherein a binding wire is fed from a continuous stock and wound around the articles. Subsequent to this process the two ends of the binding wire are twisted with each other in the known apparatus. In this state of the art, however, the binding wire consists only of a single piece, so that the resulting fastening of the articles is relatively weak. The object of the invention is to provide a method of tying one or more articles by forming a U-shaped tying wire from a continuous stock to facilitate easy and firm tying without undue rupture of the tying wire. For achieving the foregoing object, the method of tying one or more articles comprises the steps of feeding a length of wire from a continuous supply; forming that length of wire in a U-shaped loop configuration; pushing the U-shaped loop to bend the closed loop end portion back towards the parallel endless wire portions to extend in a U-shaped configuration around the one or more articles; cutting the wire; and engaging the closed loop end and twisting it around the free ends of the U-shaped wire. Here, heed is to be paid to the fact that US-A-2 346 786 describes a tying machine for automatically tying several objects. In this known machine, the tying means - like the tying wire in the present invention - is taken from a continuous stock and formed into a loop. However, the tying means in this case is a twine, i.e. no inherently stable cord like a wire. This circumstance involves a completely different principle of operation compared to the use of a wire as a tying means both as concerns the forming of the loop and the holding together of the objects when winding the wire around these objects, and with respect to the provision of a solid tie. This is the reason why the principle of operation of the known machine cannot be compared with the method according to the present invention. By means of the drawings preferred embodiments of the apparatus for executing the method according to the invention are described in the following: Figs. 1(a) through 1(c) sketches showing the condition of tying articles such as reinforcing bars by the present invention method; Figs. 2(a) and 2(b) side views of important portions of an example of the mechanism for forming a U-shaped tying wire; Figs. 3(a) through 3(c) side views showing embodiments of the mechanism for guiding the tying wire; Figs. 4(a) through 4(c) front views of an important portion showing embodiments of the mechanism for twisting the tying wire; Fig. 5 a perspective view showing the tying condition when bar-like articles are connected together in the axial direction; and Figs. 6(a) and 6(b) perspective views of other embodiments when a closed mouth or mouths of a bag or bags are tied together. The method and apparatus for tying one or more articles will be explained in a specific example of tying an overlapped portion of reinforcing bars for construction or structural purposes. As shown in Figs. 2 through 4, a preferred embodiment of the apparatus for carrying out the present invention method is made up of a mechanism A for forming a U-shaped loop of a tying wire a with which the overlapped portion of the reinforcing bars E, E is tied together, a mechanism B for guiding the U-shaped loop of the tying wire a into a condition in which the closed loop end of the U-shaped loop and the parallel endless wire portions are placed close enough to allow them to be twisted together, a mechanism C for twisting the tying at the loop end and the other end of the U-shaped loop together so that the articles are fastened together, and a mechanism D for cutting the formed tying wire a to a suitable length. Each of the above-described mechanisms is incorporated into an apparatus main body 1 so that the apparatus can be operated by a driving source of relatively small electric motors or air cylinders while it is carried by an operator on a construction site. When the apparatus is put into use, the front end of the apparatus main body 1 is positioned ahead of the overlapped portion of the reinforcing bars E, E as illustrated. Each of the above-described mechanisms will now be described in more detail. Mechanism for forming the U-shaped loop. When a push button 12 or the like which is provided in the apparatus main body 1 as shown in Fig. 3 is pushed to start the operation of forming the U-shaped fold or loop, two sets of rolls 20a, 20b and 21a, 21b, provided in front of a reel 2 for supplying the tying wire a' are started to rotate. The first set of rolls 20a, 20b are rotated in the direction to pull out the tying wire a' out of the reel 2. The second set of rolls 21a, 21b, on the other hand, are reversible, i.e., they can be rotated in the same direction as the first set of rolls as well as in the oppposite direction. In front of these two sets of rolls, there is further provided a deflector or a guide member 22 which has a concave guide surface 22a on the side which faces the reel 2. A guide wheel 23 is rotatably provided in front of the guide surface 22a with a small clearance therebetween so as to be immovable in the vertical direction. This guide member 22 is so arranged that it is vertically movable, by an air cylinder mechanism 24 or the like, from the position shown in thick lines in Fig. 2(b) down to a position to stand clear of the tying wire a when the tying wire a horizontally moves to the left. The tying wire a' which is pulled out of the reel 2 strikes against the deflector 22 and then moves along the clearance between the guide wheel 23 and the deflecting surface (or guide surface) 22a. During this movement, the tying wire a' changes its direction by 180 degrees by the deflecting surface 22a and will be pinched by the second set of rolls 21a, 21b. In this manner, the tying wire a' is formed into a U-shaped tying wire a . When the amount of pulling the tying wire a' by the second set of rolls 21a, 21b has become sufficient, the rotation of the second set of rolls 21a, 21b as well as that of the first set of rolls 20a, 20b are stopped. At the same time, the deflector 22 is lowered by operating the air cylinder mechanism 24 to stand clear of the tying wire a . While the rotation of the first set of rolls 20a, 20b remains the same as before, the rotation of the second set of rolls 21a, 21b is now reversed, i.e., to the same direction of rotation as that of the first set of rolls 20a, 20b. In cooperation with the first set of rolls 20a, 20b, the second set of rolls 21a, 21b thus operate to transfer or move the the U-shaped tying wire a forwards, i.e., in the direction in which the front end of the U-shaped loop leads the movement, out of engagement with the guide roll 23, as shown by imaginary lines in Figs. 2(a) and 2(b). The tying wire a may be cut by a cutter 9 to an appropriate length at a position in front of the first set of rolls 20a, 20b. In this manner, the U-shaped tying wire a of a suitable length can be formed. By the above-described rotation of the first and second set of rolls 20a, 20b and 21a, 21b, the operations are repeated, thereby forming the tying wire a in succession. The feeding of the tying wire a' may be done by rotating the reel 2 by a driving means such as an unillustrated electric motor or the like. Synchronously with this feeding operation, the feeding devices such as the rolls 20a, 20b or the like may be operated to feed the tying wire a'. Mechanism for guiding tying wire Fig. 3 (a) shows an embodiment of the mechanism B for guiding the tying wire. The front end 1' of the apparatus main body 1 is formed into a substantial semicircle so as to enclose the external surface of the overlapped portion of the reinforcing bars E, E. The loop b of the tying wire a as formed by the mechanism A for forming the U-shaped loop is fed into and along an internal arcuate edge of the semicircle 1' by means of rotation of a pair of feeding or pushing rolls 11, 11. This mechanism B is also so arranged that the loop b which projects from the front end of the semicircle 1' is positioned substantially parallel with the other end of the tying wire a so as to be suitable for the next twisting work. Further, this mechanism B for guiding the tying wire can also be arranged in the following manner. Namely, as shown in Fig. 3(b), the front end portion 1' of the apparatus main body 1 is made up of two members in the form of outside calipers 1a, 1b front ends of which can be moved towards and away from each other such that, when closed, there is formed on the internal side thereof a substantially circular guide surface for the U-shaped loop to pass through. In this arrangement, the front end portion 1' is placed in such a position as to enclose the reinforcing bars E, E while the two members 1a, 1b are opened. Once placed, the two members 1a, 1b are moved towards each other to close the front ends thereof, thus facilitating the work of enclosing the reinforcing bars E, E. Once the two members 1a, 1b are closed, there is formed on internal surfaces thereof the curved guide surface such that the tying wire a can be fed by the rotation of the pushing rolls 11, 11 along the guide surface to finally enclose the reinforcing bars E, E. In the above-described embodiment, both ends of the two members in the form of outside calipers 1a, 1b are arranged to be movable. However, needless to say, only one of them may be arranged to be movable while the other is stationary. Furthermore, the feeding of the tying wire a into the guide surface may be done at an appropriate timing, e,g., after the two members 1a, 1b have been closed or when they are partly, say, half, closed, or the like. As another embodiment of this mechanism B for guiding the tying wire, the following arrangement can also be employed. Namely, as shown in Fig. 3(c), the extension of the hook at the front portion 1' of the apparatus main body 1 is made shorter to facilitate the work of enclosing the reinforcing bars E, E. In such an arrangement, the guide surface on the internal surface also becomes shorter. It follows that the degree of bending of the tying wire a is small and, therefore, that it becomes difficult to bring the both ends of the U-shaped loop substantially parallel to each other. As a solution, by the rotating or swinging movement of a swingable or rotatable member 1c, the end of the loop b can be moved or urged from the position shown by a thick line to a position shown by an imaginary line. In this manner, the front end and the other end of the loop can be brought into a corrected position such that both ends are made close enough to be clamped in the subsequent twisting work. In the above-described embodiment, the swingable or rotatable member 1c is described to be provided only in a position which corresponds to the closed end of the U-shaped loop. However, as shown by numeral 1d in Fig. 6(c), another swingable or rotatable member may be provided in a position which corresponds to the other or opposite end (in this particular case, in the endless wire portions c of the U-shaped loop. In this manner, either one or both of them 1c, 1d may be operated to urge the U-shaped loop inwards depending on the circumstances. The mechanism B for guiding the tying wire as shown in Fig. 3(a) through 6(c) has an advantage in that the length of the apparatus main body 1 to project beyond the overlapped portion of the reinforcing bars E, E can be minimized and therefore that the tying work can be performed more advantageously. In these embodiments shown in Fig. 3(a) through 6(c), if the pushing rolls 11, 11 are replaced by the two sets of rolls 20a, 20b, 21a, 21b as shown in Figs. 2(a) and 2(b), the guiding operation to enclose the overlapped portion of the article or articles can be performed in succession to the operation of forming the tying wire a . As described above, by means of the mechanism B for guiding the U-shaped loop b of the guiding wire a , the front end and the rear (i.e., the open, free) end of the U-shaped loop b of the tying wire a are brought to a substantially parallel condition close enough to be twisted together in the subsequent twisting operation. Mechanism for twisting tying wire The mechanism C for twisting the tying wire a comprises an engaging means which is made up of a twistable shaft 5 to be rotated by a driving source such as an electric motor or the like, and a hook 6 which is provided in a projecting manner at substantially the front of the twistable shaft 5. By rotating the hook 6 several times, the hook 6 is engaged, by insertion, with the loop b of the tying wire a which is positioned within the locus of rotation of the hook 6 as shown in Fig. 4(a). At the same time, the twistable shaft 5 is rotated such that the thus engaged loop b is wound around the other ends c of the two pieces of substantially parallel tying wire a, the size of the loop b becomes smaller to tighten the other ends c, thereby gradually twisting them together to firmly fasten the overlapped portion of the reinforcing bars E, E. The front end of the hook 6 is made into a taper which becomes smaller towards the front end thereof as shown in Fig. 4(a) so that the inserting engagement of the hook 6 into, and pulling it out of, the loop b can be facilitated. As another example of the above-described mechanism C for twisting the tying wire, a hook in the form of a pair of scissors as shown in Fig. 4(b) may also be used. The hook 6 comprises a pair of holding pieces 6a, 6b which are provided at substantially the end of the twistable shaft 5 so as to be movable towards and away from each other by means of an air cylinder mechanism 6c or the like. Once the loop b is grasped when the twistable shaft 5 is twisted or rotated with the pair of holding pieces 6a, 6b opened, the holding pieces 6a, 6b are closed to securely hold the hook 6 and then rotated to twist the tying wire a as in the above-described manner. In this example, a projection 6d may also be provided on an inner intermediate portion of one of the holding pieces. In this arrangement, in holding the tying wire a , the projection 6d is engaged with the loop b, thereby preventing the loop b from being released out of engagement during twisting operation. In the above-described embodiment of twisting by means of the hook 6, there is also a case in which, as shown in Fig. 4(c), both the loop b and the end portion c of the other side of the U-shaped fold are pinched together. Mechanism for cutting tying wire The mechanism D for cutting the tying wire is, as explained above, made up of a cutter 9 which is operated by the air cylinder mechanism 14. Other arrangements than the above may, of course, be employed for this cutting mechanism. In the above-described embodiment, reinforcing bars are used as the articles to be tied at the overlapped portion. However, the articles to be tied may be other bar-like materials E such as bars, pipes, bamboos, or the like which lie parallel to each other and are to be tied together at one or more the overlapped portions, as shown in Fig. 5. The overlapped portion of two or more materials to be tied may cross each other at right angles as well as at angles other than right angles. One or more articles to be tied may, as shown in Figs. 6(a) and 6(b), also be such a closed mouth or mouths of one or more flexible container or containers such as a bag or bags E as are aligned together for tying with the tying wire. As described above, according to the present invention, since the tying work is performed by forming the U-shaped tying wire out of the continuous stock, the working efficiency is improved. Further, since the operating mechanism is integrated into the apparatus which can be hand-carried by the operator and its operation is automated, the operations of forming the tying wire, winding the tying wire around the article or articles, twisting the tying wire, and cutting it can be performed in a consecutive manner whenever the starting signal is given. Therefore, the labor of repeated manual operation, with the worker's largely bending himself over the article or articles, of the conventional method can be remarkably reduced. The time for performing the same extent of work is reduced and the working efficiency is improved. It is readily apparent that the above-described method and apparatus for tying one or more articles meet all of the objects mentioned and also have the advantage of wide commercial use.

Claims: Method for tying one or more articles comprising the steps of a - feeding a length of wire from a continuous supply; b - forming that length of wire in a U-shaped loop configuration; c - pushing the U-shaped loop to bend the closed loop end portion back towards the parallel endless wire portions to extend in a U-shaped configuration around the one or more articles; d - cutting the wire; and e - engaging the closed loop end and twisting it around the free ends of the U-shaped wire. Apparatus for carrying out the method of claim 1, the apparatus including a housing which carries a manually operable actuator; a supply of endless wire; a wire feeding means; a loop forming means; a wire clamping means; a closed loop-end bending means; a cutting device; and a rotating twisting tool engaging the closed loop end and twisting it around the parallel endless wire portions.

Inventors: SAITO TAKASHI, SAITO TSUTOMU, SATO KIYOSHI, SAITO, TAKASHI, SAITO, TSUTOMU, SATO, KIYOSHI, Sato, Kiyoshi, c/o Kabushiki Kaisha Fujita
Applicants: BENTAC CO LTD, BENTAC CO., LTD.
Application year: 1993
Main classification: B65B13
IPC codes: E04G21, B65B13