Packaging machine and means for supplying a bag-forming film

Abstract: A packaging machine has a roll supporting device (20) with a support shaft (21) rotatably supporting a film roll (R) which extends in an axial direction, an elongated bag-forming film (F) being wrapped around the film roll, a bag forming device (5) which pulls out the film from the film roll and forms the film into a shape of a bag, a packaging device (H) for filling the bag-shaped film with articles to be packaged and sealing the film to produce a package, a roll displacing mechanism (23) for displacing the roll supporting device in the axial direction, and a roll position controller for controlling the roll displacing mechanism to adjust the position of the roll supporting device. The bag forming device (3) includes a former for bending the film into a tubular form and a former roller (8) for guiding the film to the roller. As a former of a different size is installed, depending on the width of the film, the position of the former roller (8) is changed by a former roller displacing mechanism which includes a first mechanism for supporting the former roller and moving it to a plurality of different positions with respect itself and a second mechanism for moving the first mechanism to a plurality of different positions in the same direction.

Description: This invention relates to a form-fill-seal packaging machine for making packages by making bags with a flexible elongated web of bag-forming material (herein referred to as "film") and concurrently filling them with articles and sealing them, as well as a device for supplying a film to such a machine. With a so-called pillow type packaging machine, as shown in Fig. 1, which is a kind of such a packaging machine, the film F is pulled out of a film roll R around which it is wound and is passed over a diagonally disposed turn bar 15 such that its direction of transportation T is changed by 90°. The turn bar 15 is moved in the axial direction of film roll R (shown by arrow X) according to its width W such that the center line of the film F will always pass over the centers of the guide rollers 3, 4, 5, 6 and 7 which guide the film F to a bag forming device S. At the bag forming device S, the film F is passed over a former roller 8 to a former 9 by means of which the film F is bent into a tubular shape and its mutually overlapping side edges are sealed together by a longitudinal sealer 10 of a packaging device H. After the articles to be packaged are dropped into this tubularly shaped film F, a transverse sealer 11 seals the bag-shaped film F transversely and cuts it over the sealed area to produce individually separate filled bags B. When a film with a different width is used, the size of the former to be set in the bag forming device s must usually be changed also. As a small former 9a is replaced by a medium-sized former 9b and then by a large former 9c, as shown in Fig. 6, the former roller 8 must also be moved correspondingly from a closer position 8a to an intermediate position 8b and then to a farther position 8c. When a small film roll Ra is replaced by a medium-sized film roll Rb and the smaller former 9a is correspondingly replaced by the medium-sized former 9b, the distance by which the former roller 8 should be moved is L7, which is relatively small. When the small film roll Ra is replaced by a large film roll Rc and the smaller former 9a is replaced by the larger former 9c, however, this distance is L8, which is significantly larger than L7. In summary, in order to be able to make bags with a wide range of widths, the packaging machine must be able to accommodate film rolls of different lengths and to move the turn bar and the former roller accordingly by much larger distances. This means that the mechanisms for moving the turn bar and the former roller become larger and the packaging machine itself becomes large. EP-A-0549806 discloses a packaging machine comprising a roll supporting device with a support shaft rotatably supporting a film roll which extends in an axial direction, an elongated bag-forming film being wrapped around said film roll, a bag forming device which pulls out said film from said film roll and forms said film into a shape of a bag; and a packaging device for filling said bag-shaped film with articles to be packaged and sealing said film to produce a package; said bag forming device including a former for bending said film into a tubular form, a former roller for guiding said film in a film transportation direction to said former, and a former roller displacing mechanism, said former being selected from a plurality of formers with different sizes, said former roller displacing mechanism serving to move said former roller to a former roller position according to the size of said selected former along said film transportation direction, said former roller displacing mechanism including a first mechanism for supporting said former roller and a second mechanism for moving said first mechanism to a plurality of different positions in said film transportation direction. A packaging machine according to the present invention is characterised in that said first mechanism is adapted to move said former roller to a plurality of different positions with respect thereto in said film transportation direction. Typically, said first mechanism includes a rotary member which supports said former roller and is rotatable around an axis perpendicular to said film transportation direction. The second mechanism may include a screw mechanism serving to cause said rotary member to undergo a linear motion along said film transportation direction. The packaging machine preferably further comprises a controller including a former roller control means for controlling said former roller displacement mechanism to adjust the position of said former roller along said film transportation direction according to the width of said film. The support shaft may be inserted into a central opening in said axial direction of said film roll, said roll supporting device further comprising a roll stopper attached to said support shaft for contacting a backward end surface of said film wrapped around said film roll when said film roll is mounted to said support shaft. In this case, the roll stopper may include a back member which is attached to said support shaft and a stopper member which is attached to said back member and is at a displaced position displaced in a forward direction opposite said backward end surface from said back member, said stopper member contacting said backward end surface of said film without contacting said film roll. The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: Fig. 1 is in part a schematic diagonal view and in part a block diagram of a packaging machine embodying this invention; Fig. 2A is a side view of the former roller displacing mechanism of the packaging machine of Fig. 1, and Fig. 2B is a side view of a portion of the former roller displacing mechanism of Fig. 2A; Fig. 3 is a block diagram of the controller for the packaging machine of Fig. 1; Fig. 4 is a schematic side view of a portion of the packaging machine of Fig. 1, showing the motion of the rotary arms; Fig. 5 is a sectional view of a film before and after it is made into a bag by folding one of the side edges; Fig. 6 is a schematic side view of a portion of a prior art packaging machine, showing the positions of its former roller according to the size of the former. The invention is described next by way of an example. Fig. 1 shows a form-fill-seal packaging machine embodying this invention of the so-called vertical pillow type for forming a bag, concurrently filling it with articles to be packaged and sealing it. The elongated material with which the bags are formed is herein referred to as the film F. Films of different widths (such as Wa, Wb and Wc, indicated summarily by letter W) are used in the form of a film roll R. The film F, after being pulled out of a film roll R on a roll supporting device 20, is passed over a first guide roll 1 and a second guide roll 2 and is led to a turn bar 15 which is positioned diagonally to the longitudinal direction of the film F and serves to change its direction of motion (indicated by arrows T) by 90° while contacting one of its surfaces. The turn bar 15 can be moved, without changing the direction of its orientation, in the axial direction X of the film roll R by means of a turn bar shifting mechanism 16 adapted to support the turn bar 15 at both its ends. The film F is transported horizontally after its direction of motion is changed by means of the turn bar 15 and changes its direction of motion upward by going over a third guide roll 3 and a fourth guide roll 4. After the film F is passed over a fifth guide roll 5, it is transported horizontally again, and it travels on a zigzag path by passing over a sixth guide roll 6 and a seventh guide roll 7 before reaching a bag forming device S. In the bag forming device S, the film F is directed by means of a former roller 8 to a former 9 by means of which it is bent into a tubular form and is at the same time pulled downward by means of a pair of pull down belts 12 disposed opposite each other below the former 9 such that it is transported downward to a packaging device H while maintaining its tubular shape. In the packaging device H, the mutually overlapping side edge parts of the film F are longitudinally sealed together by means of a longitudinal sealer 10 into the shape of a bag, and after it is filled with articles to be packaged, the bag-shaped film F is transversely sealed by means of a transverse sealer 11 and cut such that a packaged bag B is produced. The aforementioned operations of the bag forming device S and the packaging device H are controlled by a controller 30. The bag forming device S comprises a former roller displacing mechanism 40 for changing the position of the former roller 8 along the transportation path V (in the direction indicated by arrow T) of the film F in three stages corresponding to the length of the former 9 which changes according to the film width w. As shown in Fig. 2A, this former roller displacing mechanism 40 comprises a pair of rotary left and right arms (referred to as "the first mechanism") for supporting the former roller 8 at its both ends and causing it to undergo a rotary motion and to thereby set it at two different positions along the aforementioned transportation path V of the film F and means such as a screw mechanism 60 (referred to as "the second mechanism") for causing these rotary arms 50 to undergo a linear motion along the transportation path V. The screw mechanism 60 comprises a pair of rails 63 supported by a frame 61 affixed to the base K. A slidable table 64 is placed on these rails 63 so as to be slidable thereover along the aforementioned transportation path V, and a supporting block 42 for supporting the aforementioned rotary arms 50 is affixed to this slidable table 64. Another driving motor (referred to as "the table sliding motor") 52 is attached to this frame 61. A gear 54 which is affixed to the drive shaft of the table sliding motor 52 is engaged with another gear 55 affixed to a screw bar 66 extending parallel to the rails 63. This screw bar 55 is itself a connecting member 65 attached to the bottom surface of the slidable table 64, and its front end is rotatably supported by the frame 61. Thus, as the table sliding motor 52 is activated and the gears 54 and 55 are rotated, the screw bar 66 is also rotated and this causes the slidable table 64 connected to the connecting member 65 to move on the rails 63 along the transportation path V of the film F. As the slidable table 64 is thus caused to slide on the rails 63, the axis of rotation of the rotary arms 50 is also moved (say, from position Q1 to position Q2 as shown in Fig. 4). The exact position of this axis of rotation can be determined by detecting the angle of rotation of the table sliding motor 52 by means of an optical detector such as a rotary encoder. The supporting block 42 is positioned between the pair of rotary arms 50 which it supports and contains therein still another driving motor (referred to as "the arm rotating motor") 43, the drive shaft of which is in a motion-communicating relationship through a gear mechanism of a known kind with a sectionally square shaft J2 penetrating square throughholes 50a formed through the pair of rotary arms 50. Thus, as the arm rotating motor 43 is activated, the rotary arms 50 be rotated around its axis of rotation selectably in the directions indicated by arrows C2 and C3. A positioning switch 41a such as a proximity switch for detecting the angular position of the rotary arms 50 and thereby stopping their motion is disposed at a specified position near the forward end of the trajectory of the rotary arms 50. As shown in Fig. 2B, furthermore, another positioning switch 41b such as a microswitch for detecting the position of the rotary arms 50 and thereby stopping their motion is disposed at a specified position on the upper surface of the supporting block 42, and a pushing member 45 with a protrusion 45a is affixed to the square shaft J2 for the rotary arms 50 near the supporting block 42 such that, as the rotary arms 50 rotate in the direction of arrow C3 by a certain specified angle, the pushing member 45 is rotated accordingly and its protrusion 45a applies a force on the microswitch 41b. As the arm rotating motor 43 is activated to rotate the rotary arms 50 in the direction of arrow C2 and the proximity switch 41a detects the rotary arms 50 at a specified position (as indicated by symbol P1 in Fig. 4) and is thereby switched on, a detection signal S1 is thereby outputted and received by the controller 30 (as symbolically shown in Fig. 3) and the rotary motion of the rotary arms 50 is thereby stopped. When the film width is Wa (or when a film with the smallest width is being used), the rotary arms 50 are set at this position P1. Similarly, as the arm rotating motor 43 causes the rotary arms 50 to rotate in the opposite direction (in the direction of arrow C3) and the protrusion 45a of the pushing member 45 pushes in the microswitch 41b, the presence of the rotary arms 50 at position P2 (shown in Fig. 4) is detected, another detection signal S2 is thereby outputted and received by the controller 30 (as schematically shown in Figs. 2B and 3) and the rotary motion of the rotary arms 50 is stopped. When the film width is Wb (or when a film with an intermediate width is being used), the rotary arms 50 are set at this position P2. The controller 30, of which the structure is schematically shown in Fig. 3, is adapted to control the overall operation of the packaging machine. Its functions include automatically controlling the operations of various components on the basis of inputted data on the film width W and the detection signals S1 and S2. Thus, the controller 30 includes a turn bar position control means 35 for controlling the motion and positioning of the turn bar 15, a roll position control means 36 for controlling the motion and positioning of the roll stopper 22, a former roller position control means 37 for controlling the motion and positioning of the former roller 8, a bag forming control means 38 for controlling the operations of the bag forming device S and a packaging control means 39 for controlling the packaging device H. The bag forming control means 38 serves, for example, to position the pull down belts 12 and to change the speed of transportation of the film F, depending on the type of the former 9 selected in accordance with the film width W. The packaging control means 39 serves, for example, to position the longitudinal and transverse sealers 10 and 11 and to set their temperatures and sealing pressures, depending similarly on the type of the former 9 selected in accordance with the film width W. When the information on the film width W is erroneously inputted, the controller 30 also serves to output an alarm such that operations based on such an erroneous information will be forbidden. Next, switching operations of various parts will be explained as the film width W is switched from the small (Wa) to the large (Wc). The small film width Wa may be, for example, for making bags of 5-inch size, the intermediate film width (Wb) may be, for example, for making bags of 9-inch size, and the large film width (Wc) may be, for example, for making bags of 13-inch size. Let us consider a situation where the film width is small or intermediate (Wa or Wb). First, a former 9 and a film roll R of correspondingly appropriate kinds are selected and installed. Next, the controller 30 carries out various adjustments according to the inputted film width Wa or Wb. After the former 9 has been selected, the former roller position control means 37 controls the former roller displacing mechanism 40 to appropriately position the former roller 8 as shown in Fig. 4. Explained more in detail, after the small film width Wa is indicated, the arm rotating motor 43 rotates the rotary arms 50 in the direction of arrow C2, and when the proximity switch 41a detects the rotary arms 50 at position P1, it is switched on and the detection signal S1 is outputted, thereby causing the motion of the rotary arms 50 to be stopped. The former roller 8 is thus set at position P1 corresponding to the small film width Wa. If the intermediate film width Wb is inputted, the arm rotating motor 43 rotates the rotary arms 50 in the direction of arrow C3, and when the microswitch 41b detects the rotary arms 50 at position P2, it is switched on and the detection signal S2 is outputted, thereby causing the motion of the rotary arms 50 to be stopped. The former roller 8 is thus set at position P2 corresponding to the intermediate film width Wb. If the film width is Wm1 which is between the small and intermediate values (that is, Wa < Wm1 < Wb), the screw mechanism 60 is used while the rotary arms 50 are kept at position P1. Explained more in detail, if such a film width Wm1 is inputted, when the detection signal S1 is received by the controller 30 and it is ascertained that the rotary arms 50 are at position P1, the screw mechanism 60 is activated and causes the axis of rotation of the rotary arms 50 to undergo a linear motion from position Q1 in the direction T1 opposite to the direction T along the transportation route V by a specified distance corresponding to the length of the former selected by this film width Wm1. This specified distance is smaller than the distance L3 between positions Q1 and Q2. Thus, if the film width is Wa or Wb, various parts of the packaging machine are adjusted as described above and the film F is supplied from the film roll R under this condition, the film F is formed into a bag at the bag forming device S, articles are supplied into the bag at the packaging device H, and a filled bag B is produced. In the case of a film with a large width Wc, another former 9 of a different type and a wide film roll Rc corresponding to the inputted film width Wc are set. For this former 9, the roll position control means 36 controls the former roller displacing mechanism 40 to position the former roller 8. In this case, the arm rotating motor 43 causes the rotary arms 50 to rotate in the direction of arrow C3 as shown in Fig. 5 until the microswitch 41b detects the rotary arms 50 at position P2 and is thereby switched on, stopping the rotation of the rotary arms 50. As the detection signal S2 is received by the controller 30 and the presence of the rotary arms 50 at position P2 is thereby ascertained, the screw mechanism 60 causes the axis of rotation of the rotary arms 50 to move linearly fron position Q1 to position Q2 as shown in Fig. 5 in the direction of arrow T1 opposite the direction of film transportation T along the film transportation path V by a distance L3 depending upon the size of the newly installed former 9. As a result, the former roll 8 is now at position P3 shown in Fig. 5. The distance between positions P1 and P3 is the same as the distance by which the former roller of a prior art packaging machine will have to be moved as explained above with referenced to Fig. 10, that is, it is L8. If a film width Wm2 which is between Wb and Wc (that is, if Wb < Wm2 < We) is inputted, after the detection signal S2 is received by the controller 30 and the presence of the rotary arms 50 at position P2 is thereby ascertained, the screw mechanism 60 causes the axis of rotation of the rotary arms 50 to move linearly from position Q1 in the direction of arrow T1 as shown in Fig. 4 to a specified position determined by the kind of the former 9 corresponding to the inputted film width Wm2. The distance by which the axis of rotation of the rotary arms 50 in this case is smaller than L3. Alternatively, the former roller displacing mechanism 40 may be structured such that the supporting block 42 of the rotary arms 50 is moved first to position Q2 by means of the screw mechanism 60 and then the rotary arms 50 are rotated to position P2 or position P3 corresponding respectively to film width Wb and Wc. It is to be noted that the former roller displacing mechanism 40 thus structured, when the film width W is changed, moves the former roller 8 both by rotating the rotary arms (or the first mechanism) 50 and by moving the screw mechanism (or the second mechanism) 60 linearly. Thus, even if the film width W is changed by a relatively large amount, the distance by which the former roller must be moved by the screw mechanism 60 is much less than required by a prior art packaging machine. In other words, the present invention can prevent the packaging machine from becoming too large. The invention has been described above basically by way of one example. Many modifications and variations are possible within the scope of the claims. For example, although what was referred to as the first mechanism 50 was formed with a pair of rotary arms, this may be substituted by another mechanism for effecting a linear displacement along the transportation route V such as a mechanism similar to the screw bar 60. Similarly, the former roller displacing mechanism 40 need not comprise a screw mechanism. It may be realized, for example, by a timing belt stretched over a pair of pulleys or a mechanism using a fluid cylinder to move the table 54.

Claims: A packaging machine comprising: a roll supporting device (20) with a support shaft (21) rotatably supporting a film roll (R) which extends in an axial direction, an elongated bag-forming film being wrapped around said film roll, a bag forming device (S) which pulls out said film from said film roll and forms said film into a shape of a bag; and a packaging device (H) for filling said bag-shaped film with articles to be packaged and sealing said film to produce a package; said bag forming device (S) including a former (9) for bending said film into a tubular form, a former roller (8) for guiding said film in a film transportation direction to said former, and a former roller displacing mechanism (40), said former being selected from a plurality of formers with different sizes, said former roller displacing mechanism serving to move said former roller along said film transportation direction to a former roller position according to the size of said selected former, said former roller displacing mechanism including a first mechanism (50) for supporting said former roller and a second mechanism (60) for moving said first mechanism (SV) to a plurality of different positions in said film transportation direction, characterised in that said first mechanism (50) is adapted to move said former roller to a plurality of different positions with respect thereto in said film transportation direction (V). The packaging machine of claim 1, wherein said first mechanism includes a rotary member (50) which supports said former roller and is rotatable around an axis perpendicular to said film transportation direction. The packaging machine of claim 1 or claim 2, wherein said second mechanism includes a screw mechanism (60) serving to cause said rotary member to undergo a linear motion along said film transportation direction. The packaging machine of any of claims 1 to 3, further comprising a controller (30) including a former roller control means (37) for controlling said former roller displacement mechanism to adjust the position of said former roller along said film transportation direction according to the width of said film. The packaging machine according to any of the preceding claims, wherein said support shaft (21) is inserted into a central opening in said axial direction of said film roll, said roll supporting device (20) further comprising a roll stopper (22) attached to said support shaft for contacting a backward end surface of said film wrapped around said film roll when said film roll is mounted to said support shaft. The packaging machine according to claim 5, wherein said roll stopper (22) includes a back member (22a) which is attached to said support shaft and a stopper member (22c) which is attached to said back member and is at a displaced position displaced in a forward direction opposite said backward end surface from said back member, said stopper member contacting said backward end surface of said film without contacting said film roll.

Inventors: FUKUDA MASAO, FUKUDA, MASAO, Fukuda, Masao, c/o Ishida Co., Ltd.
Applicants: ISHIDA SEISAKUSHO, ISHIDA CO., LTD.
Application year: 1998
Main classification: B65B9
IPC codes: B65H23, B65B9