AUTOMATIC PACKAGING METHOD AND APPARATUS

Abstract: An automatic packaging apparatus has a bed-plate (3) on which objects are packaged. A tape guide is provided which can be swivelled to one side. The guide functions to form into a loop packaging tape (4) fed by a tape transport section. Placing the object to be packaged in the loop triggers a sequence of operations which enables the package to be bound automatically without the tape tangling or catching.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an automatic packaging apparatus for tightly binding packages with tape of a thermoplastic material such as polypropylene. Description of the Prior Art There have been various apparatuses for binding packages with packaging tape. Commonly known types comprise a work-table on which is positioned an arc-shaped tape support frame around which the packaging tape is fed, and by reeling the tape in, the tape is drawn out of the support frame and bound around the package. A drawback of this system is that because the tape support frame is positioned beforehand on the work-table, packages that are larger than the support frame cannot be handled. To overcome this drawback, US-A-4 079 667 and JP-A-49(1974)-4520 offered a method and apparatus comprised of an arc-shaped guide member covered by a band-end clamping base-plate provided near the surface of the work-table, whereby a packaging tape or band is fed from below the base-plate and along the guide member and the end of the band is then clamped to form a ring, the guide member is then removed from over the base-plate and more of the band is paid out to enlarge the ring into a loop, into which the merchandise is inserted and the band drawn tightly around it, the band being joined where it overlaps and cut. However, drawbacks with this apparatus were that the function of the arc-shaped guide member was not only to guide the end of the band under the base-plate, but because of the need, after the formation of the ring, for it to be positioned where it would not cause any obstruction to operations resulting from opening or other such operation performed by moving means, preferably for it temporarily to be retracted beneath the work-table surface, it was implemented as two guide pieces roughly symmetrical in shape, from considerations of rationality. As such, it was necessary to provide areas of open space on each side of the guide fixing position on the work-table and the precision of the joint section of the two parts of the guide member had to be increased to prevent tangling of the tape or band, in addition to which the tape would fall out of the guide groove or would catch in the groove and be difficult to free. The object of the present invention is therefore to provide an automatic packaging method and apparatus whereby tangling of the tape loop by the guide member is prevented when the latter is retracted from the initial loop. This object is solved by contracting the loop to release it from the guide, by means of which the tape is prevented from falling out of the guide groove or from catching. An automatic packaging apparatus comprised of a transport mechanism which, when a guide that is swivellably provided on a packaging bed-plate for guiding packaging tape into a loop is set into position on the bed-plate by the urging of a solenoid, feeds the tape into and through the guide, and when the leading end of the tape is detected by a tape position detection switch provided at a specified position, a camshaft is activated and a section of the said tape is pressed and held by means of a fixing cylinder, the transport mechanism is reversed to contract the loop of tape, and after the guide is released from its position, the loop is formed to a specified size on the bed-plate and the object to be packaged is placed in the loop, and an ON signal from the work detection switch reverses the transport mechanism, binding the tape around the object, rotation of a camshaft is activated to operate a heating mechanism at the surfaces of the tape overlap, the overlapping tape surfaces being welded by a pressure-welding cylinder and excess tape cut off by a cutter on the pressure-welding cylinder, said transport mechanism being controlled by a control circuit section by means of a gate control circuit which discriminates as input the signals of the various switch contact input circuits, and timing control circuits connected to the gate control circuit which operate the various mechanisms by means of switch circuits connected to the gate control circuit. BRIEF DESCRIPTION OF THE DRAWINGS The objects and features of the present invention will now be described in detail with reference to the accompanying drawings in which: Figure 1 is a perspective view of the exterior of the automatic packaging apparatus according to the present invention; Figure 2 is a perspective view of the automatic packaging apparatus with its bed-plate/cover and main unit cover removed; Figure 3 is a side view of the apparatus; Figure 4 is a front cross-sectional view of the pressure welding mechanism of the apparatus; Figure 5 is a side view of the heating mechanism; Figure 6 is a plane view of the guide part of the guide mechanism; Figure 7 is a block diagram of the control circuit section; Figure 8 is a circuit diagram of the control circuit section; and Figure 9 is an apparatus sequence control diagram. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying Figures 1 to 9. As shown in Figure 1, an automatic packaging apparatus 1 is comprised of a main casing 2 on which is provided a bed-plate 3. On the bed-plate 3 is formed a loop of packaging tape 4 composed of a thermoplastic material such as polypropylene. An object (now shown) to be packaged which is inserted into this loop pushes against a work detection switch 5 attached to the side of an extension 2a located at the left side of the bed-plate 3 of the main casing 2, to bind the packaging tape 4 in place around the object. The bed-plate 3, which also acts as the top cover of the main casing 2, is provided at its center with a groove 3a, the width of which is slightly greater than that of the packaging tape 4. The packaging tape 4 is raised at a specified position in the groove 3a to form the loop, and is inserted also into other positions in the groove 3a. The bed-plate 3 is divided at right-angles to the groove 3a, the right-hand section 3c of this divided section 3b being openable toward the back, as viewed in the figure. The packaging tape 4 is housed in a housing 6 provided inside this openable right-hand section 3c. A control circuit section 23 for the automatic packaging apparatus 1 is provided in the extension 2a of the main casing 2 on the left side of the divided section 3b, and a switch panel 24 containing power switches and the like is attached to the front of the extension 2a. With reference to Figure 2, which shows the automatic packaging apparatus 1 with the main casing 2b of the bed-plate 3 and the main casing 2 removed, the housing 6 is provided at the right-hand side of the chassis 2c of the main casing 2. On the frame 6a of the housing 6 is rotatably supported a tape holder 4a which has wound thereon a roll of the packaging tape 4. A partition 6b is provided on the left side of this housing 6. Leftwards from the housing 6 are provided a transport mechanism 7, pressure-welding mechanism 9, heating mechanism 16, guide mechanism 18 and the control circuit section 23. The packaging tape 4 contained in the housing 6 is threaded through a tape-feeding opening 6c to the transport mechanism 7, to locate it in a guide 19 of a guide mechanism 18 on the bed-plate 3, whereupon the transport mechanism 7 is activated by a signal from the control circuit section 23, the packaging tape 4 thereby being moved along the guide 19 and formed into a loop. At this point, the leading end of the packaging tape 4 is detected by a tape position detection switch 21 and is fixed into position by means of the pressure-welding mechanism 9 located beneath the bed-plate 3. Then, under the urging in the opposite direction by the transport mechanism 7, the loop of packaging tape 4 contracts. The loop of packaging tape 4 contracts inside the guide 19, and the guide 19 is swivelled into the extension 2a so that it does not catch the packaging tape 4. The transport mechanism 7 is again activated and the packaging tape 4 is moved to form a loop of the specified size on the bed-plate 3, which is the state shown in Figure 1. When in this state the object to be packaged is placed inside the loop of packaging tape 4 on the bed-plate 3, pressing the work detection switch 5, the transport mechanism 7 reels in the packaging tape 4, binding the tape in place around the object. When the control circuit section 23 confirms that this binding has been performed, the heating mechanism 16 is activated to heat the overlapping surfaces of the packaging tape 4 and the pressure-welding mechanism 9 is driven to pressure-weld the said overlapping surfaces. Finally, the cutter 14c of the pressure cylinder 14 provided on the pressure-welding mechanism 9 cuts off the excess packaging tape 4 to thereby complete the sequence of packaging operations. Each of the mechanisms involved will now be explained with reference to Figure 1, which shows a side view of the automatic packaging apparatus 1. The transport mechanism 7, which performs the feeding and reeling-in of the packaging tape 4, is comprised of as tape inlet 7a positioned to correspond with the tape-feeding opening 6c provided in the portion 6b for communication therewith, and a guide channel 7b is formed as an extension of the tape inlet 7a. A drive roller 7d is provided at part of the guide channel 7b, and a guide roller 7c is provided which is in contact with the peripheral surface of the drive roller 7d. Downstream of the point of contact between the drive roller 7d and the guide roller 7c, the guide channel 7b is formed following the peripheral surface of the drive roller 7d and is connected at its end to a supply outlet 11 provided below the bed-plate 3. As shown in Figure 4, a movable plate 8 is provided over the supply outlet 11, and the inside of the supply outlet 11 is divided into an upper and a lower passage by an intermediate member 8a affixed below the movable plate 8. The end of the guide channel 7b is connected to the lower one of the passages divided by the movable plate 8. The drive roller 7d is connected to the shaft 7m of a separately-provided motor 7e (Figure 8) and in accordance with command signals from the control circuit section 23 (described later) is rotated clockwise (forward) or counterclockwise (reverse). The guide roller 7c is rotatably supported by a support member 7f that is supported so that it can swing up and down with a screw 7g as the fulcrum. The support member 7f is constantly urged upwards by a coil spring 7h on a bolt 7i provided in a chassis 2c. Therefore, the guide roller 7c pressed against the drive roller 7d through the medium of the packaging tape 4 in the guide channel 7b rotates together with the rotation of the drive roller 7d, enabling the packaging tape 4 to be transported. The numeral 7j denotes a nut provided on the bolt 7i, the urging force of the coil spring 7h being adjustable by adjusting the position of this nut 7j. To prevent the packaging tape 4 from dropping out of the guide channel 7b, the front of the transport mechanism 7 is covered with a sheet of clear resin which is attached by a screw 7k. Next, as shown by Figure 4, the pressure-welding mechanism 9 has as camshaft 10 which passes through the lower part of sidepl ates 9a, 9a provided vertically on the chassis 2c, a cylinder block 12 and a coupling member 9b. An engagement slot 9c is provided on the upper surface of the coupling member 9b, and by means of the engagement slot 9c the movable plate 8 provided beneath the bed-plate 3 is slidably attached so that it can be moved back and forth, with respect to the drawing of Figure 4. Furthermore, the movable plate 8 is provided with an intermediate member 8a which also is slidable back and forth with respect to Figure 4. The movable plate 8 and the intermediate member 8a are both urged in one direction (to the front, in Figure 4) by springs (not shown). The intermediate member 8a is located in the center of the supply outlet 11 provided directly beneath the movable plate 8, and is arranged so that the supply outlet 11 is divided in two. The movable plate 8 and intermediate member 8a are moved by the cam-plate 10e of the camshaft 10, as described later. The cylinder block 12 is affixed at a specified position on the sideplates 9a, 9a and is provided with three cylinder bores for the insertion of three cylinders. From the left in the figure, the cylinders are a tying cylinder 13, the pressure-welding/cutting cylinder 14 and a fixing cylinder 15. The three cylinders 13, 14 and 15 are inserted into the cylinder bores in the cylinder block 12 so as to be vertically slidable. The tying cylinder 13 has a main cylinder member 13a and an integrally formed solid block 13b at the top thereof, and provided inside the block 13b is a tape passage 13c, formed of sloping walls, through which the packaging tape 4 passes. An upper blade 13d is formed on the upper left edge of the tape passage 13c. A stepped section 13e is provided at the top of the tying cylinder 13. After the leading end of the packaging tape 4 loop has been inserted, fed through to the upper part of the supply outlet 11 and been stopped by the tape position detection switch 21 provided on the outlet side of the supply outlet 11, the stepped section 13e, together with part of the movable plate 8, clamps the free end of the packaging tape 4. Like the tying cylinder 13, the pressure-welding/cutting cylinder 14, provided adjoining on the left of the tying cylinder 13 has a main cylinder member 14d which can slide in the cylinder. The top of a block section 14a provided at the upper part of the 14d is formed into a flat section 14b. This flat section 14b is for pressing the packaging tape 4 against the underside of the movable plate 8, and is provided with a cutter 14c on its right side. The cutter 14c abuts the left side of the tying cylinder 13, and in conjunction with the upper blade 13d of the tying cylinder 13 cuts off excess packaging tape 4 on the upstream side. The fixing cylinder 15 provided on the left of the pressure-welding/cutting cylinder 14 is provided with the top of a main cylinder member 15c with a block 15b having a projection 15a on its upper edge. The projection 15a on the block 15b can detachably engage with a groove section 9d on the underside of the movable plate 8 to clamp the packaging tape 4 on the downstream side. The above main cylinder members 13a, 14d and 15c each have a roller attached at the lower end, and cam plates 10a, 10b and 10c affixed to the camshaft 10 disposed beneath the rollers are urged into resilient contact therewith by a spring (not shown). The camshaft 10 is coupled to a motor 10f by means of a train of gearwheels, which is not shown in Figure 4, being off to the left (see Figure 2). A datum detection circuit 22, described later, is provided above the camshaft 10, which ensures the datum of the camshaft 10 and also detects inclination of the camshaft 10. Another cam-plate 10d is provided between the cam-plate 10a and the cam-plate 10b affixed on the camshaft 10, and another cam-plate 10e is provided between cam-plate 10b and cam-plate 10e. These cam-plates 10d and 10e work the heating mechanism 16 and the supply outlet 11 of the movable plate 8, respectively. The heating mechanism 16 is comprised of a bearing shaft 16a, which projects inwardly from the sideplates 9a, 9a beneath the camshaft 10, a shank 16b that rests on the bearing shaft 16a, and a heater member 17 provided at the top of the shank 16b (Figure 5). The heater member 17 is a slab-shaped member, and a heating device is housed in a case 17a attached to the underside thereof, the heater member 17 providing heat at all times. A bearing hole 16c for holding a roller is provided in the intermediate section of the shank 16b of the heating mechanism 16. The roller affixed on the inner side of this bearing hole 16c is pressure-contacted with the cam-plate 10d on the camshaft 10 by means of a spring (not shown). The moving mechanism of the movable plate 8 is similar in construction to the cam mechanism of the heating mechanism 16. Specifically, the heating mechanism 16 has a bearing shaft 16d provided on the opposite side to the bearing shaft 16a (Figure 4), a shank 16e is slidably attached to the bearing shaft 16d, and via a roller attached to an intermediate section of the shank 16e, a spring provides pressure-contact with the cam-plate 10e on the camshaft 10, so that the rotation of the cam-plate 10e causes a back-and-forth rocking motion about the bearing shaft 16d. The top of the shank 16e communicates depthwise, with respect to the drawing, with the movable plate 8 and the intermediate member 8a, and in time with the swinging of the shank 16e, the movable plate 8 and intermediate member 8a are moved depthwise. This operation is also the same with respect to the shank 16b of the heating mechanism 16. The heater member 17 comes between the overlapping surfaces of the packaging tape 4 just as the intermediate member 8a is moved out from between the overlapping surfaces. Also, simultaneously with the completion of the welding of the packaging tape 4 by the pressure-welding/cutting cylinder 14, the movable plate 8 on top of the intermediate member 8a is moved depthwise out of the way by the turning action of the cam-plate 10e, enabling the object being packaged to be removed from the bed-plate 3. The guide mechanism 18 is provided on the adjoining left side of the pressure-welding mechanism 9 (Figure 3). The guide mechanism 18 guides the packaging tape 4 conveyed from the transport mechanism 7 and forms it into a loop on the bed-plate 3. With reference to Figure 3, provided on the chassis 2c are a solenoid 18a, a rack 18b coupled to the actuator end of the solenoid 18a, a coil spring 18f (Figure 2) which constantly urges the rack 18b to the right, and a toothed-belt pulley 18c coaxial with the gearwheel 18g that meshes with the rack 18b. A toothed-belt pulley 18d of the ame diameter is rotatably supported on the left-hand sideplate 9a of the pressure-welding mechanism 9, a toothed belt 18e runs vertically around the toothed-belt pulleys 18d and 18c, and the guide 19 is fixed on the same spindle as the toothed-belt pulley 18d. As shown in Figure 6, the guide 19, which is comprised of two flat, transparent sideplates 19b, 19b, is formed at one edge into a crescent shape, and on the other edge it is formed into a cutout section 19a which covers the movable plate 8 provided below the bed-plate 3. Provided at one end of the flat sideplates 19b, 19b is a shaft hole 19c for the insertion thereinto of the spindle of the toothed-belt pulley 18d. Between the flat sideplates 19b, 19b is a guide surface 20 that is formed slightly wider than the width of the packaging tape 4 and which follows the outer rim of the crescent. The end of the packaging tape 4 inserted into the left-hand side of the guide surface 20 is moved along the guide surface 20 to form a loop. With the rack 18b urged to the right by the coil spring 18f, the guide 19 is usually in an upright position (the position shown in Figure 3 by the double-dot chain line). When the solenoid 18a is energized by a signal from the control circuit section 23, described later, the rack 18b is moved to the left, causing the pinion in engagement with the rack 18b to rotate clockwise. This clockwise rotation turns the toothed-belt pulley 18c clockwise, and by means of the toothed belt 18e the toothed-belt pulley 18d is also turned clockwise, setting the guide 19 into position on the bed-plate 3 (the position shown in Figure 3 by the solid line). When the solenoid 18a is de-energized, the rack 18b is moved to the right by the force of the coil spring 18f, rotating the guide 19 counterclockwise to be held in the vertical position shown by the double-dot chain line. When the guide 19 is set into place, the left and right sides of the cutout portion 19a locate in the groove 3a of the bed-plate 3, the left side of the guide 19 is in alignment with the lower part of the supply outlet 11 and the right side with the upper part thereof. Therefore, the packaging tape 4 led through from the lower side of the guide 11 is guided by the guide surface 20 to the upper side of the supply outlet 11, to form a loop. The end of the tape 4 guided to the upper part of the outlet 11 comes into contact with a tape position detection switch 21 provided at the opening of guide 11 (Figure 4). The signal from the tape position detection switch 21 stops the shaft 7m of the motor 7e in the transport mechanism 7, halting the transport of the tape 4. The structure of the control circuit section 23 which controls each of the mechanisms of the automatic packaging apparatus 1 is shown in Figure 7. Contact input signals from the work detection switch 5, datum detection switch 22, tape position detection switch 21 and a tape-tightened signal input section 30 are sent to a contact input section 25. The output signal from this contact input section 25 is input to a gate control circuit 26 (Ic1). Contact input signals from the switch panel 24 are directly input into the gate control circuit 26. The gate control circuit 26 is a programmable logic array gate circuit which mainly discriminates the outputs of the contact input section 25, outputs signals to a switch circuit 27 and to the program timers Ic4, Ic5, Ic6, Ic7 and Ic8 for sequential control of the automatic packaging apparatus 1. The output side of the switch circuit 27 provided on the output side of the gate control circuit Ic1 is connected to the motor 7e, the motor 10f and the solenoid 18a. The program timer Ic7 is connected to the output terminal Ic1-22 of the gate control circuit Ic1, and controls the timing of the commands to energize the solenoid 18a for the positioning of the guide 19 on the bed-plate 3. The program timer Ic7 has a time constant circuit C13 to delay the energization of the solenoid 18 to prevent the guide 19 from being immediately positioned on the bed-plate 3 when the object to be packaged is separated from the work detection switch 5, the time constant being variable. The program timer Ic8 is connected to the program timer Ic7 and controls the timing of the commands to rotate the transport motor 7e forward to transport the packaging tape 4 along the guide 19. The program timer Ic8 has a time constant circuit C15 which delays the start of the motor 7e's forward rotation until the operation of the solenoid 18a has securely positioned the guide 19 on the bed-plate 3; the time constant circuit C15 is also provided with a variable resistor. The program timer Ic4 is connected to the output terminal Ic1-15 of the gate control circuit Ic1 and controls the timing of the commands to stop the reverse rotation of the motor 7e. The program timer Ic4 has a time constant circuit C7 to set the time of contraction of the loop of packaging tape 4 in the guide 19. The program timer Ic5 is connected to the program timer Ic4 and controls the timing of commands to rotate the motor 7e forward to expand the loop of tape again, and is provided with a time constant circuit C9 to confirm that the guide 19 is ins ide the extension 2a before th motor 7e is rotated forward. The program timer Ic6 is connected to the program timer Ic5 and controls the timing of commands to rotate the motor 7e forward to expand the loop of tape to a specified size that allows the insertion therein of the object to be packaged. All of the circuits are reset by the provision of an output signal from program timer Ic6 to input terminal Ic1-13 of the gate control circuit Ic1. The program timer Ic6 contains a time constant circuit C11 which controls the period of forward rotation of the motor 7e by the program timer Ic5 and sets the period of expansion of the loop of tape 4. Again, the resistance which sets the time constant is variable, enabling the size of the loop to be changed. A power supply circuit 28 supplies the various circuits with specified voltages (5V, 12V, 24V). The operation of the automatic packaging apparatus will now be explained, with reference to Figure 8, which is a circuit diagram of the control circuit section 23, and Figure 9, which shows the sequence of operations of the automatic packaging apparatus according to this invention. The sequence of Figure 9 starts with an object to be packaged being inserted into an expanded loop formed on the bed-plate 3. When the object switches on the work detection switch 5, a signal is input to input terminal Ic1-1 of gate control circuit Ic1, via contact input circuit 25, and from the output terminal Ic1-21 of the gate control circuit Ic1 a signal is supplied to a motor 7e reversing relay PY1 via a switch circuit 27 photocoupler PC5. The motor 7e is thus reversed and the tape 4 is tightened around the object. The tightening of the tape 4 imposes a load on the output shaft of the motor 7e, reducing the speed of rotation thereof. When the shaft speed reaches a predetermined value, a motor speed detection circuit (not shown) outputs a tape-tightened signal to a tape-tightened signal input section 30. This tape-tightened signal goes to input terminal Ic1-4 of gate control circuit Ic1, a signal is output from output terminal Ic1-19 of gate control circuit Ic1 to switch circuit 27 photocoupler PC7, the cam motor 10f is activated to displace the camshaft 10 to a specified position and the tape in the lower part of the supply outlet 11 is fixed in place by the projection 15a of the fixing cylinder 15 and the groove portion 9d of the movable plate 8. The camshaft 10 operates the heating mechanism 16 to insert the heater member 17 and apply heat at the overlapping portion of the tape 4. The camshaft 10 continues to turn, operating the pressure-welding cylinder 14 and retracting the heater member 17. The overlapping tape 4 portion is then pressure-welded by the lower surface of the movable plate 8 and the flat portion 14b on the pressure cylinder 14, while at the same time the tape 4 is cut by the combination of the cutter 14c and the upper blade 13d of the tying cylinder 13. The cam-plate 10e rotation as the camshaft 10 is returning to its datum causes the shank 16e to swing and the movable plate 8 to be moved depthwise, with respect to the drawing. When the camshaft 10 reaches its datum the tying cylinder 13, pressure-welding cylinder 14 and fixing cylinder 15 are all at their lowest position. Also, simultaneously with the return of the camshaft 10 to its datum, the datum detection switch 22 supplies a signal to gate control circuit Ic1 input terminal Ic1-2, and from gate control circuit Ic1 output terminal Ic1-19 a signal is supplied via switch circuit 27 photocoupler PC7 to cam motor 10f drive relay PY2, stopping the driving of said cam motor 10f. When the object bound by the tape is removed from the bed-plate 3, the work detection switch 5 is switched off, and this signal is supplied to gate control circuit Ic1 input terminal Ic1-1 and an output signal from gate control circuit Ic1 output terminal Ic1-22 is su pplied to program timer Ic7 via time constant circuit C13. Next, an output signal from program timer Ic7 is supplied to gate control circuit Ic1 input terminal Ic1-8 and the output from gate control circuit Ic1 output terminal Ic1-18 is supplied to the solenoid 18a via switch circuit 27 photocoupler PC8. The solenoid 18a is thereby energized, driving the guide mechanism 18 to position the guide 19 on the bed-plate 3. The time constant circuit C13 functions so that the guide 19 is not driven the instant the object is removed from the work detection switch 5, eliminating the risk that the operator may be injured by such instantaneous positioning. The output of the program timer Ic7 is supplied to program timer Ic8 via time constant circuit C15, and the output of program timer Ic8 is supplied to gate control circuit Ic1 input terminal Ic1-9. A signal from gate control circuit Ic1 output terminal Ic1-20 is supplied to the transport motor 7e forward relay PY3 via switch circuit 27 photocoupler PC6. As a result, the motor 7e performs forward rotation, feeding the tape through the guide 19. Because of the presence of the time constant circuit C15, the tape is only moved through the guide 19 after the guide 19 has been securely positioned on the bed-plate 3. Next, when the leading end of the tape 4 contacts the tape position detection switch 21, a signal from the said detection switch 21 is input to gate control circuit Ic1 input terminal Ic1-3, via contact input circuit 25. As a result, a signal from gate control circuit Ic1 output terminal Ic1-19 is supplied to relay PY2, via switch circuit 27 photocoupler PC7, driving the cam motor 10f and thereby turning the camshaft 10, and the stepped portion 13e of the tying cylinder 13 functions in combination with the lower surface of the movable plate 8 to hold the free end of the tape just before the supply outlet 11, and at the same time the datum detection switch 22 is switched off. When the said detection switch 22 is switched off, this signal is supplied to gate control circuit Ic1 input terminal Ic1-2, a signal from gate control circuit Ic1 output terminal Ic1-19 is supplied via switch circuit 27 photocoupler PC7 to relay PY2, and the driving of the cam motor 10f is stopped. Also when the datum detection switch 22 switches off and the signal is supplied to the gate control circuit Ic1 input terminal Ic1-2, a signal is also output from gate control circuit Ic1 output terminal Ic1-18 via switch circuit 27 photocoupler PC8, stopping the energization of the solenoid 18a. Again, when the datum detection switch 22 switches off, a signal which is also output from gate control circuit Ic1, output terminal Ic1-21 is supplied to relay PY1 via switch circuit 27 photocoupler PC5. As a result, the transport motor 7e is reversed, starting contraction of the tape in the guide 19. When the datum detection switch 22 switches off, an output signal from gate control circuit Ic1 output terminal Ic1-15 is also supplied to the program timer Ic4 via the time constant circuit C7. The output of the program timer Ic4 is suppied to gate control circuit Ic1 input terminal Ic1-10, and from the gate control circuit Ic1 output terminal Ic1-21 a signal is supplied via switch circuit 27 photocoupler PC5 to relay PY1. As a result, reverse rotation of the motor 7e is stopped with the loop of tape in the guide 19 contracted to the specified size. The tape contraction time is set by the time constant circuit C7. At this time the solenoid 18a is de-energized, with the result that the guide 19 swivelled by the force of the coil spring 18f is smoothly separated from the contracted tape loop. The signal from the program timer Ic4 output terminal is supplied to program timer Ic5 via the time constant circuit C9. The program timer Ic5 outputs a signal from output terminal Ic5-3 after the period of time set by the time constant circuit C9 has elapsed, i.e., after the contracted loop has definitely separated from the guide 19. The output signal from the program timer Ic5 is supplied to gate control circuit Ic1 input terminal Ic1-11, and from gate control circuit Ic1 output terminal Ic1-20 an output goes to relay PY3 via switch circuit 27 photocoupler PC6. As a result, the motor 7e rotates forward and expansion of the loop of tape starts. At the same time, an output signal from program timer Ic5 is supplied, via time constant circuit C11, to the program timer Ic6. After the lapse of the period of time set by the time constant circuit C11, the program timer Ic6 supplies a signal to the reset terminal Ic1-13 of gate control circuit Ic1. As a result, gate control circuit Ic1 is reset, reverting to its initial state, while at the same time a signal from output terminal Ic1-20 is also supplied to relay PY3, via the switch circuit 27 photocoupler PC6. As a result, the rotation of the motor 7e is stopped, with the loop of tape on the bed-plate 3 at a size capable of allowing the packaging object to be inserted therein. Thus, the size of the expanded loop of tape is determined by the time constant circuit C11. This means that after the expanded loop has been formed on the bed-plate 3, it is possible to repeat the process to tie the tape around subsequent packaging objects. In the case of this automatic packaging apparatus 1, when the bed-plate 3 loop is too small to insert the object, a monitor switch provided on the switch panel 24 allows the loop to be expanded by causing the transport motor 7e to rotate forward. When the binding is insufficient, it is also possible for the monitor switch to be used to reverse the transport mechanism. Also, if the timing of the camshaft 10 operation is off, a cam monitor switch can be used to adjust the timing apropriately. Thus, as described in the above, an automatic packaging apparatus wherein tape fed by a transport mechanism is formed into a loop by means of a guide that is swivellably provided on a packaging bed-plate, the leading end of the tape is detected by a tape position detection switch, the detection signal drives a cam motor, a section of the said tape is held, the transport mechanism being reversed at this time to contract the loop of tape, and after the guide has been retracted, the loop is expanded to the specified size, the object to be packaged is placed in the loop and the work detection switch is operated to reverse the transport mechanism, binding the tape around the object, at which time the surfaces of the tape overlap are heated and then welded by a pressure-welding cylinder and excess tape cut off, said transport mechanism being controlled by timing control circuits on the basis of contact input control circuits and signals discriminated by a gate control circuit, a one-piece guide being used from which the packaging tape does not not fall out or catch on or the like.

Claims: An automatic packaging method comprising: feeding, from a supply outlet (11) provided beneath a bed-plate (3) on which an object to be packaged is to be placed, packaging tape (4) so that the tape (4) follows a guide surface (20) above the bed-plate (3) and formed into a loop and its end being stopped at the supply outlet (11); fixing part of the packaging tape at the supply outlet (11); in the state where the loop has exited from the guide surface (20), the process of supplying the tape (4) from the supply outlet (11) and expanding the loop in accordance with the size of the object to be wrapped; and placing the object to be packaged on the bed-plate (3) in the expanded loop, drawing in the loop to tie the tape (4) around the object, welding the overlapping surfaces of the tape and cutting the tape (4) at the supply outlet side, characterized in that the fixing part of the packaging tape (4) is followed by reeling in part of the tape (4) to contract the loop formed in alignment with the guide surface (20). An automatic packaging apparatus comprising: a guide mechanism (18) swivellably provided in the vicinity of the bed-plate (3) on which the object to be packaged is placed and having a guide surface (20) for guiding the tape (4) to form a loop on the bed-plate (3); transport mechanism (7) which feeds the tape (4) along the guide surface (20) via the supply outlet (11) provided beneath the bed-plate (3), stops the tape (4) at the supply outlet (11) by means of a tape position detection switch (21), forms a loop, expands the loop to a specified size and, by means of signal input from a detection switch (5), tightens the loop of tape around the object to be packaged; a pressure-welding mechanism (9) provided with a tying cylinder (13) which can be pressed against a coupling member (9b) positioned at the supply outlet (11), for holding a portion of the tape (4), a pressure-welding cylinder (14) adjoining the tying cylinder (13) for pressure-welding overlapping surfaces of the loop, cutters (14c) on the sliding surfaces of the tying cylinder (13) and the pressure-welding cylinder (14) for cutting off the excess tape, a fixing cylinder (15) adjoining the pressure-welding cylinder (14) for clamping the tape (4), and a camshaft (10) that operates said cylinders (13,14,15); a heating mechanism (16) for heating the overlapping portions of the tape in conjunction with the rotation of the camshaft (10); a supply outlet mechanism for moving said supply outlet (11) beneath the bed-plate (3) and releasing same, in conjunction with the rotation of the camshaft (10); a control circuit section (23) comprising a gate control circuit (26) into which are input signals from switch contact input circuits (27), discriminates said input signals and directs them to the predescribed circuits, activates via the switch circuits (27) connected to the gate control circuit (26) a transport motor (7e) for driving forward and reverse the transport mechanism (7), a cam motor (10f) for driving the pressure-welding mechanism (9) and a solenoid (18a) for swivelling the guide mechanism (18), and timing control circuitry for controlling the timing of the said drive portions connected to the gate control circuit (26); characterized in that said gate control circuit (26) activates said transport motor (7e) in the reverse direction for reeling in part of the tape (4) after forming the loop guided by the guide mechanism (18), so that the loop is contracted before swivelling the guide mechanism (18) in its inoperative position. The automatic packaging apparatus according to claim 2 wherein the guide mechanism (18) comprises a guide (19) consisting of two congruent flat plates (19b,19b) formed at one edge into a semicircular shape and at the other into a cutout section (19a) which locates in a groove (3a) of the bed-plate (3) and which has at one end a shaft hole (19c) for the insertion of a splined spindle, having a space between the flat plates (19b,19b) through which the tape (4) passes and a guide surface (20) on the semicircular side, said guide (19) having a first pulley (18d) fixed on said spindle which is coupled by a belt (18e) to a second pulley (18c) which is via a pinion in mesh with a rack (18b) that extends from a solenoid (18a), thus rotating the guide (19) when the solenoid (18a) is energized.

Inventors: MITANIHARA, MAKOTO, SEKINE, TASUO
Applicants: KABUSHIKI KAISHA SATO
Application year: 1987
Main classification: B65B13
IPC codes: B65B13