EP0646526B1 - Flap folding device of a wrapping machine - Google Patents

Description

BACKGROUND OF THE INVENTION

The present invention relates to a wrapping machine with a flap folding device for folding the protruding ends of a wrapping sheet of kraft or the like paper, after it has been wrapped around an approximately rectangular item referred to herein as the "content" which may be for example a stack of paper, a number of books, belt-like cloth or textile folded longitudinally in a zig-zag form, or a stack of boxes.

The flap folding device has a pair of side-folding guides which are arranged on the same planes as the open sides of the content and can move into contact with, and away from, the side flaps of the protruding ends of the wrapping sheet. As the side-folding guides contact the side flaps, the side flaps are folded inward along the open side of the content, and subsequently, remaining lower and upper flaps at each protruding end are folded in order along the open side of the content.

One known form of flap folding device of this type, is disclosed in Japanese Utility Model Laid-open No. Hei 332004. In this known device, projections are provided in the vicinity of the upper and lower ends of each side flap by forming each side-folding guide so that it is a little smaller in a vertical size than that of the content. These side-folding guides are caused to approach both side flaps, until the upper and lower projections hit against the upper and lower ends of each side flap.

Furthermore, as disclosed in Japanese Utility Model Laid-Open No. Hei 2-23305, each side-folding guide is composed of a pair of upper and lower plates, which are horizontally rotatable such that a clearance between the upper and lower plates can be adjusted in accordance with a change in the vertical size of the content. These side-folding guides rotate, substantially simultaneously, until they hit against the upper and lower ends of both side flaps.

Thereafter, the side-folding guides are horizontally moved along the open side of the content, pushing the upper and lower ends of both side flaps as in a straight state from the base end to the forward end, while folding each side flap at the base end at a right angle until the whole of the side flap is flat against the open side. At the same time, the lower flap and the upper flap are folded at both side ends, at 45 degrees, to produce a horizontal folding line, to be protruded out horizontally.

Furthermore, as disclosed in for example Japanese Patent Publication No. Hei 3-14685, with the content placed on a wrapping sheet which has been fed onto an elevator, a switch is manually operated to thereby lower the elevator to fold up the wrapping sheet in a nearly U shape. Thereafter, the wrapping sheet and contents are horizontally transferred by a transfer means from the elevator to a discharge table, where both ends of the folded wrapping sheet are lapped over the upper surface of the content, thus finishing the body wrapping process. At the same time, the side flap positioned on the upstream side in the direction of transfer is folded, by the side-folding guide connected by the transfer means, along the open side of the content, and then the side flap positioned on the downstream is folded along the open side of the content by a fixed side-folding guide. Thereafter, the upper flap is folded down along the open side and at the same time an adhesive tape fed out by a tape feeding mechanism is attached by a taping mechanism on both overlapped ends of the wrapping sheet to close these overlapped ends. Subsequently, after the upward folding of the lower flap along the outer side of the upper flap that has been folded, the forward end of the lower flap which has been overlapped on the extreme outer side by the inward protruding motion of the guide is folded along the upper surface of the content, and then the adhesive tape fed out by the tape feeding mechanism is affixed on the forward end of the lower flap and on the upper surface of the content to seal them.

Swiss Patent 390776 shows a somewhat similar device to that described immediately above, and United States Patent No 3006119 discloses a machine in which a sheet of paper or the like is wrapped around contents by raising the contents on an elevator to the underside of the sheet so that the sheet wraps around the contents in a U shape, following which the free edges are wrapped so as to overlap, whereby the contents become held by the tubular wrapped sheet whose ends are subsequently folded to complete the wrapping. The folding of the ends is effected by feeding the partially wrapped contents past folding guides.

These prior-art flap folding devices of the wrapping machine described above, however, are not able to accommodate changes in content and sheet size and some have a problem that the side-folding guide simply moves horizontally along the open side of the content to be wrapped, to push to fold the upper and lower ends of the side flap as in a straight line, and therefore the side flap facing the closed side of the wrapped body of the content is likely to swell at the vicinity of the base end when the side flap is folded at the base end.

Furthermore, as the side flap is folded at two places, upper and lower, by the side-folding guide, when the height of the content has been changed, it is necessary to change the vertical size of the side-folding guide according to the change, and also to make positional adjustment of the side-folding flap so that the side-folding guide will face the upper and lower ends of the side flap. The flap folding device, therefore, has the problem that it is not easily adjustable and usable, and furthermore becomes complicated in structure due to the adoption of the side-folding guide adjusting mechanism described. The size of the machine on the whole is also increased thereby.

Furthermore, the upper flap and the lower flap are folded obliquely at 45 degrees at both side ends when the whole of either of the side flaps is folded. Therefore in the case of the so-called normal folding wherein each protruding end protrudes by an amount less than a half of the width of the open side of the content, the upper and lower flaps are folded separately and obliquely at 45 degrees without interfering with each other.

In the case of the so-called overlap folding, wherein each protruding end protrudes by more than a half of the width of the open side of the content, the forward ends of these 45-degree oblique folded flaps meet, interfering with each other. Accordingly, if, the flaps are folded forcibly, the wrapped article will have a bad outward appearance, resulting in a lowered commodity value.

Consequently, in the case of the so-called overlap folding, it may be that flap folding is impossible, excluding overlap folding from the normal operating range of the machine. Then, for example the size of the wrapping sheet will usually be changed to allow the so-called normal folding to take place. However, even this type of wrapping is impossible when very few kinds of wrapping sheets suitable for normal folding are available.

Furthermore, there is also the following problem Each side-folding guide, after hitting against each side flap, moves horizontally along the parallel open sides of the content. When the content is light in weight it is likely to move off the mounting position as a result of shock caused by the hitting of each side-folding guide against the side flap. Also, if the content supplied has moved off the mounting position due to for example a dimensional error of the content, the error in the mounting position of the content will be increased due to the shock caused by the hitting of the side folding guide against the side flap. If the timing of the hitting of the side-folding guide against the side flap is off, the content more easily moves off position; resulting in a defectively folded side flap.

In the prior-art wrapping machine, both the so called fold-down wrapping for folding down the forward end of the upper flap on the outermost side and along the underside of the content and the so-called fold-up wrapping for folding up the forward end of the lower flap on the outermost side and along the upper side of the content are not performed by a single flap-folding device. That is, each of the fold-down wrapping and the fold-up wrapping requires a separate device. The adoption of separate flap-folding processes for fold-down and fold-up wrapping, however, presents the problem that the device on the whole will become large in size.

The present invention seeks to provide a machine which provides improved packaging of contents in that the folding device will perform normal folding and overlap folding by inputting numerical values without adjusting the side-folding guides irrespective of a change in the size of the content and the wrapping sheet.

According to the invention there is provided wrapping machine with a flap folding device for folding the protruding ends of a wrapping sheet of kraft or the like paper, after it has been wrapped around an approximately rectangular item referred to as the "content", said folding device having a pair of side-folding guides which move toward, and away from, both side flaps at each overhang end of the wrapping sheet which protrudes in a square cylindrical form from an open side of the content on the same plane as said open side, for folding said side flaps inward along said open side of said content and thereafter a lower flap and an upper flap in order, at the remaining overhang ends along said open side of said content, said flap fold device being characterised by an elevating means for time shifting the contact-rotation between said pair of side folding guides and both of said side flaps and elevating either one of said content and said side folding guides, an input means for variably inputting the width of each open side of said content, the length intersecting said width, the height of the content, and the length and width of the wrapping sheet, a computing means for computing the overhang length of each overhang end of said wrapping sheet on the basis of data outputted from said input means, a comparing means for comparing a result of this computation with half of the width of said open side and a control means for controlling operation of a guide moving means in accordance with the result of computation.

Furthermore, it is preferable that the elevating means be an elevator on which the content whose body part has been wrapped is mounted, the height position of the elevator being controlled by the control means, and the side-folding guide being arranged so that it may not be vertically movable for adjustment.

Furthermore it is preferable to mount the lower or upper flap guide for subsequently folding of the side flap so that the guide can vertically reciprocate along the open side of the content, to control the level of the elevator by the control means, and at the same time to control the end-of-folding position of the guide.

The actual construction and operation of the a machine according to the present invention, will become more apparent and understandable from the following detailed description thereof, when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a front view in longitudinal section showing one embodiment of a wrapping machine according to the present invention the figure showing both the start and end of wrapping positions;

Fig. 2 is a plan view in transverse section of the machine of fig. 1;

Fig. 3 is a front view in partly longitudinal section showing in a series of steps how the content is wrapping with a wrapping sheet;

Fig. 4 is a plan view in transverse section of part of the machine showing the content at the end of the initial wrapping process and includes a block diagram showing machine controls;

Fig. 5 is a circuit diagram of a control circuit of the machine;

Fig. 6 is a flowchart showing how the machine is set for different sizes of content and wrapping sheet;

Fig. 7 is a partly cutaway front view showing the position of tall content at the start of folding;

Fig. 8 is a partly cutaway front view similar to figure 7 showing a small content;

Fig. 9 is a partly enlarged plan view in transverse section showing the side flap in the course of folding;

Fig. 10 is a partly cutaway front view showing the same position as figure 9 and showing tall content;

Fig. 11 is a partly cutaway front view similar to figure 10 showing a small content;

Fig. 12 is a partly enlarged plan view in transverse section showing the side flap immediately before the end of folding;

Fig. 13 is a partly cutaway front view of position of figure 12, and showing tall content;

Fig. 14 is a partly cutaway front view similar to figure 13 but showing a small content;

Fig. 15 is a partly enlarged plan view in transverse section showing the upper flap at the start of down folding;

Figs. 16 and 17 are respectively a partly cutaway front view and a longitudinal sectional side view of the position shown in figure 15;

Fig. 18 shows in perspective view and in a series of steps, the flap folding processes of the down-folding wrapping; and

Fig. 19 shows similarly to figure 18, the flap folding processes of the up-folding wrapping.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter one embodiment of the invention of a wrapping machine with a flap folding device will be described with reference to the accompanying drawings.

To simplify the understanding of the operation of the machine, it is explained that the machine is for wrapping the content B with a wrapping sheet A which is initially positioned at position P1 with the content B on top of same. The content B and sheet A are lowered whilst on an elevator 2 to position P1', and during this movement the wrapping sheet is wrapped into U-shape around the bottom B5 and the upstream side B2(x) and the downstream side B2(y) of the content B. Sides B2 are referenced B2(x) and B2(y) in figure 1 only. Whilst the content B and sheet A are in position P1', the sheet is wrapped over the top B4 so that the ends overlap, and they are sealed to connect the overlapped ends together. This results in that the wrapping sheet takes up a tubular but rectangular cross sectional form around the content, and the ends A1 of the tube protrude from the ends B1 of the contents. These ends comprise upstream and downstream side flaps A2, A2 and a top flap A4 and a bottom flap A3. This stage is considered the partial or initial wrapping stage of the operation, and is not part of the present invention.

From the position P1', the partially wrapped content and the wrapping sheet are moved horizontally to position P2', and finally they are moved by the elevator 2 to the position P2 which is at the same level as and adjacent to the position P1. Between the time the content has been partially wrapped, and when it reaches the position P2, the protruding ends of the wrapping sheet are folded by the end folding device onto the open ends B1 of the content B and they are sealed to complete the wrapping

In the present embodiment, as shown in Figs. 1 and 2, the folding device includes four side-folding guides 1 which face side flaps A2 of both overhang ends A1, A1 the content. The elevator 2 is for lifting either the content B or the side-folding guides 1. The content B, after the completion initial wrapping stage is horizontally transferred by a transfer means 3 along a mounting surface 2a of the elevator 2 that has lowered from the wrapping start position P1. Then, side flaps A2 of both overhang ends A1, A1 are folded inward by means of side- folding guides 4, 4. Thereafter, the elevator 2 rises to push the content B upward to the wrapping end position P2, where upper flaps A4, A4 are pushed to hit against folding guides 5, 5, and are folded down until they overlap the outer side of the lower flaps A3, A3, and the forward ends of the upper flaps A4, A4 are sealed with pre-affixed adhesive tape C2, C2.

The side-folding guides 1 comprise rods which are of much less height and longer in a lateral direction than the content B. Of these side-folding guides 1, the two upstream side folding guides can be reciprocated in the direction of transfer of the content B by transfer means 3, to a middle position between the upstream and downstream side flaps A2 on the overhang ends A1, A1. The two side folding guides 1 located on the downstream side of the content B are not movable in the direction of transfer of the content B. At the lateral middle position the guides 1 are rotatably supported for folding the side flaps A2, in that inner hitting parts 1a are formed to lie opposite and nearly parallel to the closed sides B2, B2. Initially, the guides are spaced from the content B, and folding parts 1b are formed, on the outer ends of the rods to lie opposite and nearly parallel to the side flaps A2.

Furthermore, each side-folding guide 1 is rotatably supported on a support shaft 1c which also forms a spiral guide path as a guide moving means. As shown in Figs. 10 and 11, when the hitting part 1a comes into contact with the content B, the rod 1a, 1b makes a quarter turn in the direction of folding of the side flaps A2 while turning on the corners of the sides B1, B1, B2, B2 of the content B. With this quarter turn, the folding part 1b is lowered to a specific level toward the lower flaps A3, A3 until it faces the downstream side flap A2 to be folded by the folding part 1b of the downstream side folding guide.

The upstream side- folding guides 1, 1 are provided with rotatably mounted up-folding means along the upper end of the inner surface thereof, for moving movable upright surfaces 1e, 1e into contact with, and away from, the open sides B1, B1 of the content B. The movable upright surfaces 1e, 1e, in the initial state when they are spaced form the content B, are inclined in a direction in which the upright surfaces 1e, 1e slope away from the open sides B1, B1. To apply the movable upright surfaces 1e, 1e to sides B1, B1 they are gradually moved upright by a cam or the like, by moving pressing surfaces 1f, 1f horizontally outward from the bottom end of the folding parts 1b, 1b as shown in Fig. 9.

Furthermore, the support shafts 1c, 1c of these upstream side- folding guides 1, 1 are connected to a driving unit such as a stepping motor, and are moved forwardly and backwardly by this driving unit. On the backward path, fixed return projections 1g, 1g installed as the reversion holding means as shown in Fig. 15, engage the guides as explained hereinafter.

The driving unit of the upstream side- folding guides 1, 1 is connected with a control circuit 10, which controls the operation of the driving unit. In the initial state, up to the completion of the initial wrapping process, the hitting parts 1a, 1a and the folding parts 1b, 1b are held on standby in a position where the wrapping sheet A and the content B being carried downward on the elevator 2 are not interfered with. Nearly simultaneously with the forward movement of the transfer means 3, the hitting parts 1a, 1a are moved in the same direction. By reason of an overlap-folding signal inputted from the control circuit 10, the folding parts 1b, 1b stop nearly in the medium position of the open sides B1, B1 of the content B. After the completion of the first transfer of the content B by the transfer means 3, the content B approaches the folding parts 1b, 1b of the downstream side- folding guides 1, 1. These guides rotate while the upstream side flaps A2, A2 that have been folded are held folded.

When a normal-folding signal has been given by the control circuit 10, after the completion of the first transfer of the content B by the transfer means 3, the folding parts 1b, 1b are moved forward sufficiently to ensure that the upstream side flaps A2, A2 are folded. Subsequently, the folding parts 1b, 1b are moved further forward at the same speed simultaneously as the transfer speed of the content B, to approach the folding parts 1b, 1b of the downstream side- folding guides 1, 1 that have rotated. In this position, the folding parts 1b, 1b of the upstream guides stop forward movement. Thus, the content B is delivered to the downstream side- folding guides 1, 1 while holding the upstream side flaps A2, A2 folded, and then the upstream side- folding guides 1, 1 are moved backward to the upstream side. Thereafter, the upstream side- folding guides 1, 1 are moved backward to the upstream side, into engagement with the return projections 1g, 1g which force the side folding guides 1, 1 to turn in a direction reverse to folding to reset the upstream guides to the initial state.

The downstream side- folding guides 1, 1 have fixed upright surfaces 1h, 1h along the upper edge of the inner surface, which lie opposite to the open sides B1, B1 of the content B when the downstream guides are rotated. The fixed upright surfaces 1h, 1h are provided, as an up-folding means, at their upper edges with upwardly inclined sides 1h', 1h' as they extemd from the folding part 1b, 1b side toward the hitting part 1a, 1a side as shown in Figs. 13 and 14. Also, projections 1i, 1i having an acute-angle section are provided on the lower end of the hitting parts 1a, 1a and are inclined in a direction in which they extend away from the open sides B1, B1 of the content B, as they move toward the forward end of the folding parts 1b, 1b of the fixed upright surfaces 1h, 1h. Furthermore, temporary holding parts 1j, 1j comprising for example permanent magnets or electromagnets are fixedly mounted as a reversion holding means in the vicinity of the holding parts 1b, 1b of the downstream side- folding guides 1, 1. The hitting parts 1a, 1a are held on standby, nearly parallel with the downstream closed side B2 of the content B that has been transferred by the transfer means 3, and the undersides of these hitting parts are provided with inclined cam faces 1k, 1k. When the inclined cam faces 1k, 1k have rotated in the direction of folding, they are engaged with the inclined sides 4a, 4a of the up- folding guides 4, 4 as described below, so that the downstream side- folding guides 1, 1 are forced to turn in the reverse direction of folding, to be reset to the initial state, to thereby facilitate the rotation of the hitting parts 1a, 1a.

Also, when the content B is high, pressing rods 1l, 1l are installed, as occasion requires, which extend nearly horizontally from the support shafts 1c, 1c of the downstream side- folding guides 1, 1 to the up folding guides 4, 4 described below as shown in Fig. 16; and there is provided a clearance between the pressing rods 1l 1l and the open sides B1, B1 of the content B through which the up- folding guides 4, 4 can pass. These pressing rods 1l, 1l are brought into contact with the side flaps A2 that have been folded, thereby holding them in the folded state until the completion of up-folding of the lower flaps A3, A3 by the up- folding guides 4, 4.

The elevator 2 has a mounting surface 2a which the bottom surface B5 of the content B contacts. The mounting surface 2a is arranged so that it can reciprocate vertically along an elevating path 2b. This mounting surface 2a is of such width in the direction that the content B is horizontally carried by transfer means 3, as shown in Fig. 4, to mount two contents B in parallel in the direction of transfer, and is formed in the lateral direction narrower at the downstream side than at the upstream side, and nearly the same as, or shorter than, the length in the lateral direction of the smallest content B to be accommodated by the machine. Under the elevator 2 on the downstream side are connected arms 2c, 2c which protrude outwards in the lateral direction.

On these arms 2c, 2c are vertically mounted hanging- flap receiving bases 2d, 2d, which can reciprocate in the lateral direction. These hanging flap receiving bases 2d 2d are so arranged-that their upper surfaces are at the same level as the mounting surface 2a, and they are connected, as shown in Fig. 16, by connecting pieces 2e, 2e to support frames 5b, 5b of the folding guides 5, 5 described later. Thereby, the upper surfaces of the hanging- flap receiving bases 2d, 2d are supported contiguously on the right and left ends of the bottom surface B5 of the content B, corresponding to a change in the length of the content B. To the arms 2c, 2c and the mounting surface 2a is connected the driving unit of for example the stepping motor, to move the driving unit upward and downward.

The driving unit of the elevator 2 is connected to, and controlled by, the control circuit 10 described later, in the same manner as the driving unit of the above-described upstream side- folding guides 1, 1. When an overlap folding signal has been inputted from the control circuit 10 in the initial state immediately after the completion of the initial wrapping process, the mounting surface 2a and the hanging- flap receiving bases 2d, 2d are elevated so that they will take up a vertically nearly middle position to face the hitting parts 1a of the side-folding guides 1 stated above, regardless of the height of the content B.

When a normal-folding signal has been entered from the control circuit 10, the mounting surface 2a and the hanging- flap receiving bases 2d, 2d are moved upward or downward until the bottom surface B5 of the content B is at nearly the same level as the bottom end of the folding part 1b of the side-folding guides 1, regardless of the height of the content B. After the completion of forward movement of the transfer means 3 and the first upward movement of the up- folding guides 4, 4, the mounting surface 2a and the hanging- flap receiving bases 2d, 2d are moved upward to the same upper-limit position as the upper surface of the folding guides 5, 5. Then, with the start of the subsequent body wrapping process, the mounting surface 2a and the hanging- flap receiving bases 2d, 2d are lowered to be reset to the initial state.

The transfer means 3 is so mounted vertically through the mounting surface 2a of the elevator 2 that it can reciprocate in the direction of transfer with its vertical pushing surface 3a arranged below the folding guide 5, 5. The transfer means 3 is connected with a driving unit such as the stepping motor, by which the pushing surface 3a is reciprocated. The driving unit of the transfer means 3 is connected to the control circuit 10 described later, by which the operation of the driving unit is controlled. In the initial state immediately after the completion of the initial wrapping process, the pushing surface 3a is held on standby on the same vertical surface as the upstream closed side B2 of the content B. The forward movement of the pushing surface 3a is started nearly simultaneously with the forward movement of the upstream side-folding guides 1, 1and continues until the downstream closed side B2 of the content B comes to a stop in a position hitting against the hitting parts 1a, 1a of the downstream side- folding guides 1, 1. Subsequently, the upstream side- folding guides 1, 1 move forwardly to a specific position in relation to the open sides B1, B1, and the pushing surface 3a moves again further forwardly at the same speed, until it stops in a position located further downstream than the downstream side- folding guides 1, 1. It then moves backward to the upstream side during, or after the end of, upward movement of the elevator 2, to return to the initial state.

The up- folding guides 4, 4 are vertically installed to lie in nearly the same planes as the parallel open sides B1, B1 of the content, and close to the downstream side of the downstream side- folding guides 1, 1 when in standby position. At the upper downstream ends of the up- folding guides 4, 4 are formed the inclined sides 4a, 4a which are gently inclined upward and face the lower flaps A3, A3 as shown in fig. 16. The up- folding guides 4, 4 are supported to be movable vertically, and have protruding parts, such as sponges 4b, 4b which contact the adhesive surface of the adhesive tapes C2, C2 affixed on the forward end of the upper flaps A4, A4. Also, the up- folding guides 4, 4 are connected to the driving unit such as the stepping motor, by which their vertical movement is effected.

The driving unit of the up- folding guides 4, 4 is connected with the control circuit 10 described later, by which the operation of the up- folding guides 4, 4 will be controlled. In the initial state immediately after the completion of the initial wrapping process, the guides 4, 4 are moved to adjust their upper edge level slightly higher than the mounting surface 2a irrespective of the downward stroke of the mounting surface 2a of the elevator, on the basis of an overlap or normal-folding signal entered from the control circuit 10. When an overlap-folding signal is received from the control circuit 10 after the end of the forward movement of the transfer means 3, the content B is moved upward to a position in which the upper surface B4 of the content B will not be below the oblique folding line A4' of the upper flaps A4, A4. Thereafter, the up- folding guides 4, 4 are further raised to the vicinity of the lower end of the folding guides 5, 5 at the same speed as the speed of the mounting surface 2a and at the same time as the upward movement of the mounting surface 2a.

The folding guides 5, 5 are supported above the up folding guides 4, 4 and are connected to a driving unit so that their inner ends 5a, 5a can move in the lateral direction toward, or away from, each other. The support frames 5b 5b are laterally adjustably mounted above the up- folding guides 4, 4 to enable them to be adjusted corresponding to a change in the length of the content B. The inner ends 5a, 5a of the folding guides 5, 5 are laterally movably supported on the support frames 5b, 5b. The folding guides 5, 5 are connected to weights 5c, 5c so that a specific pressure will be applied by the plates to stoppers 5d, 5d which limit the projection of the inner ends 5a, 5a. These stoppers can be released to allow the projection of the inner ends 5a, 5a towards each other by the contacting of the upper surface B4 of the content B when the elevator 2 is raised. Reset means 5e, 5e serve to reset the guides 5, 5.

When the inner ends 5a, 5a of the folding guides 5, 5 are reciprocated by the driving unit, this driving unit is connected to and is controlled by, the control circuit 10 described later. In the initial state, the inner ends 5a, 5a are kept on standby and in the same plane as the open sides B1, B1 of the content B which is moved upward by the elevator 2. They are pressed with a specific amount of pressure against the open sides BI, B1 of the ascending content B. Then, immediately after the content B passes through between the inner ends 5a, 5a, the inner ends 5a, 5a protrude out along the bottom surface B5 of the content B. After the end of this projection, the inner ends 5a, 5a are moved in the reverse direction of projection simultaneously with the descent of the elevator, and return to the initial state.

To enable the inner ends 5a, 5a of the folding guides 5, 5 to be moved by the weights 5c, 5c in a direction in which they approach each other, the weights 5c, 5c are connected to the inner ends 5a, 5a by a wire member such as a wire, which passes round a rotatable roller installed on the support frames 5b, 5b.

The stoppers 5d, 5d are vertically movably mounted on the support frames 5b, 5b, so as to be movable vertically into contact with, and away from, the inner ends 5a, 5a with the movement of the content B on the elevator 2. The stoppers 5d, 5d are constantly pressed by an elastic member such as a spring in a direction in which they will contact the inner ends 5a, 5a, and also are moved away from the inner ends 5a, 5a by the hitting of the right and left ends of the upper surface B4 of the ascending content B on the stoppers.

The reset means 5e, 5e in the present embodiment, provide that the inner ends 5a, 5a are connected by an elastic member such as a spring or a wire member such as a wire to the arms 2c, 2c. After the descent of the elevator 2 from the upper-limit position to a specific level position, the inner ends 5a, 5a are moved by the reset means away from each other, thus returning to the initial state.

Furthermore, below the inner ends 5a, 5a of the folding guides 5, inclined surfaces 5f, 5f are formed on the support frames 5b, 5b. These surfaces 5f, 5f incline downward in a direction away from the open sides B1, B1 of the content B. They may be formed integral with the inner ends 5a, 5a. The surfaces are formed on angle sections 5g, 5g projecting downwards, to fold down the upper flaps A4, A4. Sections 5g, 5g face the central part of the upper flaps A4, A4.

Furthermore, in the transfer path 3b and between the side-folding guides 1 and the up- folding guides 4, 4 are arranged down- folding guides 6, 6 as shown in Fig. 19. The down- folding guides 6, 6 have edges which incline downward so that as the content B moves toward the downstream side in the direction of transfer, these edges hit and fold down the upper flaps A4, A4 along the open sides B1, B1. The down folding guides are supported to be movable out of the transfer path 3b or movable backward and forward.

Furthermore, near the folding guides 5, 5 is installed a spring loaded support means which protrudes to lie along the bottom surface B5 of the content B after it has been carried upward on the elevator 2. This support means, as shown in Fig. 12, comprises a latch 7 which projects a short distance from the support frames 5b, 5b of the folding guides 5, 5. It is resiliently loaded by an elastic member 7a such as a spring. There is also a latch 8 which projects to nearly the center of the bottom surface B5, and which is movable into, and out of, a recess 2f formed by a cut out in the downstream end of the mounting surface 2a of the elevator 2. The upper end surfaces of these latches 7 and 8 are arranged at substantially the same level as the upper surfaces of the folding guides 5, 5 and support the bottom surface B5 of the content B in their projected state.

The latch 8 has an upright piece 8b on the base 8a. Base 8a is arranged at a lower level than the lower limit position of the mounting surface 2a as shown in Fig. 1. The upright piece 8b is movable backward and forward in the direction of transfer of the content B. Between this upright piece 8b and the frame 8d is interposed an elastic member 7c such as a spring for pressing the upright piece 8b constantly toward the upstream side.

Furthermore, in the case of the present embodiment, the wrapping sheet A wrapped on the body of the content B is located with the forward end A5 bent obliquely upward as shown in Fig. 1. The forward ends A5 in the supply A6 are bent back by the use of a tape attaching mechanism 11, which attaches the adhesive tapes C1, C2, C2 to the forward end A5 of the top wrapping sheet A so that the tapes C1, C2, C2 project therefrom. The sheets A are fed out one by one by a sheet feeding mechanism 12 toward and into the wrapping start position P1, ti take up a specific position on the elevator 2.

With the content B placed on the wrapping sheet A in position P1, the wrapping sheet A and the content B are lowered by the elevator 2 as shown in Fig. 3 (a), the wrapping sheet A being folded up in the form of a U shape along the sides B2, B2 and the bottom surface B5 of the content B. Thereafter, the elevator 2 is moved slightly upward as shown in Fig. 3 (b), so that the content B is compressed between the compression plates 13, 13, and the elevator 2. Next, the body wrapping guides 14, 14 are moved towards each other along the upper surface B4 of the content B as shown in Figs. 3 (c) to (f), thus folding the forward end A5 and last end A6 of the wrapping sheet A along the upper surface B4 of the content B so that these ends overlap. At the same time, the adhesive tapes C1, C2, C2 adhered to the forward end A5 are adhered to the end A6 to seal the content B. Thereafter the elevator 2 moves slightly downward as shown in Fig. 3 (g), releasing the compression from the content B. Finally the compression plates 13, 13 are pulled out, thus finishing the initial wrapping process.

Mounted above the elevator 2 at the wrapping start position P1 are reference guides 15. These guides 15 engage sides B2, B2 and sides B1, B1 of the content B when placed in the wrapping start position P1, to properly position the content. Horizontally between the wrapping start position P1 and the wrapping end position P2 is installed a guide path 16 for holding the forward end A5 of the wrapping sheet A in an upwardly inclinded position.

On the upper surface of the device are installed, as shown in Fig. 2, a sheet feed start switch S1, a wrapping start switch S2, a wrapping changeover switch S3, and an input means 9, for example a keypad. The input means 9, as shown in Fig. 4, is connected to the control circuit 10, to enter the width W of each open side B1, the length L at right angles to width W, and height of the content B. Before starting any wrapping operation, these sizes are changed as necessary, as are the length SL and width of the wrapping sheet A, and these values are displayed on a display 9a such as a CRT.

The control circuit 10 comprises a computing means, a comparison means, and a control means, and has an input interface 10a, a microcomputer 10b comprising ROM, RAM and CPU, and an output interface 10c.

The input interface 10a functions to select either the output to the CPU, an input value from the input means 9 or the output to the CPU, an output signal from the sheet feed start switch S1, the wrapping start switch S2, and the wrapping changeover switch S3.

The ROM of the microcomputer 10b stores a program for controlling the CPU. The CPU takes in the necessary outside data from the input interface 10a in accordance with the program, performs arithmetic processing while receiving data from, and outputting data to, the RAM, and outputs the processed data to the output interface 10c when required.

Following manual operation of the sheet feed start switch S1, the output interface 10c, upon receiving an output signal from the CPU, operates the driving unit of the tape applying mechanism 11 and the driving unit of the sheet feed mechanism 12 in order. Following manual operation of the wrapping start switch S2, the driving unit of the elevator 2, the driving unit of the compression plates 13, 13, the driving unit of the body wrapping guides 14, 14, the driving unit of the transfer means 3, the driving unit of the upstream side- folding guides 1, 1, and the driving unit of the up- folding guides 4, 4 are operated in order.

The program stored in the ROM is partly shown in a flowchart in Fig. 6, with reference to which a process for discriminating between the normal folding and the overlap folding will be explained.

When the program is started, the microcomputer 10b first reads the width W and length L of the open sides B1, B1 of the content B and the length SL of the wrapping sheet A from the input means 9, and then the remainder after subtraction of the length L of the content B from the length SL of the wrapping sheet A is divided by 2, to thereby determine an overhang length F of each overhang end A1 extending from the open sides B1, B1 of the content B.

Next, a decision is made to see whether this computation result is smaller than a half of the width W of each open side B1 of the content B. When the overhang length F of each overhang end A1 is greater than a half of the width W of each side B1, the compression plates 13, 13 are pulled out from the content B which has been wrapped with the wrapping sheet A, thus ending the initial wrapping process. Immediately after the completion of the initial wrapping process, an overlap-folding signal is outputted to the driving unit of the elevator 2, the driving unit of the upstream side- folding guides 1, 1, and the driving unit of the up- folding guides 4, 4, ending the program.

When the overhang length F of each overhang end A1 is equal to, or less than, the width W of each side B1, the compression plates 13, 13 are drawn out from the content B the body of which has been wrapped with the wrapping sheet A, ending the body wrapping process.

Immediately after the completion of the body wrapping process, a normal-folding signal is outputted to each of the driving unit of the elevator 2, the driving unit of the upstream side- folding guides 1, 1, and the driving unit of the up- folding guides 4, 4, thus finishing the program.

The wrapping change over switch S3 is used to select the so-called down-folding wrapping or up-folding wrapping as follows. First, the lower flaps A3, A3 are folded up and then the upper flaps A4, A4 are folded down. When the overhang length of the upper flaps A4, A4 overlapped on the outermost side is greater than the height of the content B, the so-called down-folding wrapping for folding the forward end of the upper flaps A4, A4 along the bottom surface B5 of the content B is selected. On the other hand, first the upper flaps A4, A4 are folded down and then the lower flaps A3, A3 are folded up. When the overhang length of the lower flaps A3, A3 overlapped on the outermost side exceeds the height of the content B, the so-called up-folding wrapping is selected for folding the forward end of the lower flaps A3, A3 along the upper surface B4 of the content B. Correspondingly to this selection, the control circuit 10 automatically changes the operation of the driving unit of the tape applying mechanism 11, the sheet feed mechanism 12, the driving unit of the elevator 2, and the driving unit of the folding guides 5, 5.

That is, in the down-folding wrapping, the tape applying mechanism 11 is used to affix the adhesive tapes C2, C2 in positions at the forward ends of the wrapping sheet. Then, the down- folding guides 6, 6 are removed or moved out of the transfer path 3b. The folding guides 5, 5 will not be allowed to protrude out even if the upper surface B4 of the content B has come up to the same level as the lower surface of the folding guides 5, 5 with the rise of the elevator 2.

In the up-folding wrapping, the tape applying mechanism 11 is operated to attach the special adhesive tape C1 for sealing the wrapped body, and then to attach the adhesive tapes C2, C2 in positions at the forward ends of the lower flaps A3, A3 of the wrapping sheet A. Then, the down- folding guides 6, 6 are installed in, or moved into, the transfer path 3b and at the same time the elevator 2 is raised until the upper surface B4 of the content B is at the same level as the lower surface of the folding guides 5, 5. When the elevator 2 has stopped at this level, the folding guides 5,5 are protruded.

Next, the operation of the flap folding device of the wrapping machine will be explained. First, the wrapping changeover switch S3 is operated to select the down-folding wrapping. In this case, the sheet feed start switch S1 is operated to supply the wrapping sheet A. Then, at the end of the initial wrapping process, particularly in the case of the so-called overlap folding, the elevator 2 is operated to adjust the level of the content B up and down so that as shown in Fig. 7 the middle of the side flaps A2 faces the side- folding guides 1,1. The inclined sides 4a, 4a of the up- folding guides 4, 4 will be slightly higher than the mounting surface 2a after the adjustment.

Also, in the case of the so-called normal folding, the elevator 2 is operated to adjust the level of the content B so that, as shown in Fig. 8, the bottom surface B5 is close to the lower end of the side folding guides 1,1, and again the inclined sides 4a, 4a of the up- folding guides 4, 4 are slightly higher than the mounting surface 2a after adjustment.

In this state the transfer means 3 moves forward to move the content B along the mounting surface 2a of the elevator 2, until the downstream closed side B2 hits against the hitting parts 1a, 1a of the downstream side- folding guides 1, 1 and the fixed upright surfaces 1h, 1h, whereby the wrapping sheet parts A7, A7 on the content B are pressed against the downstream closed side B2.

At this point in time, the forward movement of the transfer means 3 temporarily stops and the content B is held between the vertical pushing surface 3a and the hitting parts 1a, 1a, the latter being temporarily held by temporary holders 1j, 1j and the fixed upright surfaces 1h, 1h. If the content B is offset in relation to the open sides B1, B1, the position is properly corrected. At the same time, If the content B is a stack of many sheets of paper or books, the paper or books will be properly arranged.

At the same time, the downstream side flaps A2, A2 are brought against the directing plates 1d, 1d of the folding parts 1b, 1b, preventing the lower flaps A3, A3 from crushing even when the content B is small as shown in Fig. 11.

Subsequently, the upstream side- folding guides 1, 1 move forward to bring the hitting parts 1a, 1a, against the upstream closed side B2 of the held content B as shown by a full line in Fig. 9. Accordingly, the wrapping sheet parts A7, A7 near the base end of the upstream side flaps A2, A2 are pressed against the upstream closed side B2. The directing plates 1d, 1d of the folding parts 1b, 1b also hit against the upstream side flaps A2, A2 to keep the side flaps A2, A2 in a vertical direction, thus preventing the lower flaps A3, A3 from crushing, particularly if the height of the content B is small as shown in Fig. 11.

Next, the intermediate part of the inner surface of the upstream side- folding guides 1, 1 which are moving forward, as shown by chain dotted lines in Fig. 9, makes a quarter turn around the corners B3, B3, and the folding parts 1b, 1b also move downward toward the lower flaps A3, A3, thereby pulling the whole body of the upstream side flaps A2, A2 downward. Therefore, the upper part of the base end of each side flap A2 is folded tight along the open sides B1, B1 of the content B while being pressed against the corners B3, B3. At the same time, any lateral offset of the content B is corrected by the turning movement of the side folding guides 1.

Especially in the case of overlap folding, both the folding parts 1b, 1b and the movable upright surfaces 1e, 1e which gradually rise to an upright position, contact substantially the middle position in the vertical direction of the side flaps A2 that have been folded as indicated by chain dotted lines in Fig. 10, thereby scooping the upstream side flaps A2, A2 upward from below to fold the side flaps A2, A2, and, at the same time, obliquely folding the lower flaps A3, A3 along the folding lines A3', A3' and the upper flaps A4, A4 along the folding lines A4', A4'.

Furthermore, in the case of normal folding, the lower end of these folding parts 1b, 1b lowers to the vicinity of the bottom surface B5 of the content B as indicated by chain dotted lines in Fig. 11, and the pressing surfaces 1f, 1f prevent swelling of the upstream side of the lower flaps A3, A3, producing flat folding of the flaps A3, A3. At the same time, when the content B is small the upper end of the movable upright surfaces 1e, 1e is raised to an upright position and the upstream side of the upper flaps A4, A4 are folded up simultaneously with the folding of the upstream side flaps A2, A2.

Thereafter, the transfer means 3 moves forward to transfer the content B again, and the downstream side folding guides 1, I are released from the temporary holders 1j, 1j as shown in Fig. 12. The downstream side folding guides 1, 1 now make a quarter turn around the corners B3, B3, thus pulling the whole body of the downstream side flaps A2, A2 downward to fold these side flaps tight while the upper part of the base end of the side flaps A2, A2 is pressed against the corners B3, B3. At the same time, if the content B has shifted in a lateral direction, the the rotation of the downstream side folding guides 1, 1 corrects the positional shift.

At the same time, the downstream side flaps A2, A2 are swept upward from below by the upward inclined sides 1h', 1h' of the upright surfaces 1h, 1h as shown in Fig. 13. When the content B is high and the upper end of the upright surfaces 1h, 1h rising upright from the upper surface B4 thereof is low, only the downstream side flaps A2, A2 will be folded.

In the case of overlap folding, the folded downstream side flaps A2, A2 overlap with the outside of the upstream side flaps A2, A2 when the content B is carried by the transfer means 3 and the upstream side- folding guides 1, 1 are stopped in the folding position. The lower flaps A3, A3 are folded obliquely along the folding lines A3', A3' and the upper flaps A4, A4 along the folding lines A4', A4', thus being folded each into a trapezoidal form and projecting out in the lateral direction. In the case of normal folding, the lower end of the folding parts 1b, 1b lowers to the bottom surface B5 of the content B as shown in Fig. 14. When the content B is small as shown, and the upper end of the fixed upright surfaces 1h, 1h is higher than its upper surface B4, the downstream upper flaps A4, A4 are folded up at the same time as the downstream flaps A2, A2 are folded. Then, as the content B is transferred by the transfer means 3, a horizontal folding line is produced at the downstream base end of the lower flaps A3, A3 by the projections 1i, 1i which have an acute-angle section.

Thereafter, the content B passes between the inner surfaces of the downstream side- folding guides 1, 1 that have rotated as indicated in chain dotted lines in Fig. 12, and is guided to a laterally short downstream side of the mounting surface 2a. The right and left ends of the bottom surface B5 of the content B which protrude from this mounting surface 2a, are supported by the upper surfaces of the hanging flap receiving bases 2d, 2d, to thereby prevent the right and left ends of the bottom surface B5 from drooping. The base ends of the lower flaps A3, A3 are folded by hitting against the inclined sides 4a, 4a of the up- folding guides 4, 4 which are slightly higher than the mounting surface 2a of the elevator 2, and this prevents the loosening of the folded side flaps A2.

Subsequently, the downstream side B2 of the content B hits against the upright piece 8b of the latch 8 which causes the upright piece 8b to be pressed against the downstream closed side B2. Movement continues until the content B reaches a specific position, thus finishing the forward movement of the transfer means 3.

Almost at the same time, the upstream side- folding guides 1, 1 are returning and engage the return projections 1g, 1g as shown in Fig. 15, thereby forcing the upstream side- folding guides 1, 1 to turn back to the initial state. Subsequently, the up- folding guides 4, 4 begin to rise to fold the lower flaps A3, A3 onto the outside of the side flaps A2 as shown in Fig. 18 (b). When the content B is tall, the lower flaps A3, A3 are folded up to the outside of the side flaps A2 and are held in a folded state by the push rods 11, 11. At the same time, the inclined sides 4a, 4a contiguously engages with inclined cam faces 1k, 1k of the downstream side- folding guides 1, 1, forcing the downstream side- folding guides 1, 1 to turn back to return to the initial state as shown in Fig. 15.

At this time, in the case of overlap folding, the upper ends of the up- folding guides 4, 4 go up to the level where they do not contact the oblique folding lines A4' of the upper flaps A4, A4. Also in the case of normal folding, the upper ends of the up- folding guides 4, 4 rise to the vicinity of the upper surface B4 of the content B, thus ending the up-folding of the lower flaps A3, A3.

Thereafter, the mounting surface 2a of the elevator 2 and the hanging- flap receiving bases 2d, 2d move upward, and the content B, as indicated by full lines in Figs. 16 and 17 and as shown in Fig. 18 (c), is pushed upward while being guided by the up- folding guides 4, 4, the pushing surface 3a and the upright piece 8b of the latch 8. The upper flaps A4, A4 before down folding hit against the angle sections 5g, 5g of the folding guides 5, 5, which push on the centre of the upper flaps A4, A4 to thereby prevent such troubles as the entanglement of the adhesive tapes C2, C2, and the occurrence of creases in the upper flaps A4, A4.

Almost at the same time, the upper surface B4 of the content B which is moving upward is guided by the inclined surfaces 5f, 5f until the right and left ends of the upper surface B4 hit against the stoppers 5d, 5d and the stoppers 5d, 5d move away from the inner ends 5a, 5a of the folding guides 5, 5. Consequently, the inner ends 5a, 5a of the folding guides 5, 5 are pressed by the weights 5c, 5c under a specific pressure against the open sides B1, B1 of the content B.

Therefore, the upper flaps A4, A4 are gradually folded down while being pressed downward as indicated by chain dotted lines in Fig. 17 and as shown in Fig. 18 (d), and simultaneously the adhesive sides of the adhesive tapes C2, C2 on the forward ends of the upper flaps A4, A4 are attached on engaging parts 4b, 4b on the outer surface of the up- folding guides 4, 4. As the content B is carried upward on the elevator 2 it moves away from the up- folding guides 4, 4, pulling the upper flaps A4, A4 downward to overlap with the outside of the lower flaps A3, A3. As the content B goes up, the adhesive tapes C2, C2 on the upper flaps A4, A4 are detached from the engaging parts 4b, 4b. When the length of the upper flaps A4, A4 is less than the height of the content B as shown in Fig 17, the adhesive tapes C2, C2 on the upper flaps A4, A4 are affixed on the lower flaps A3, A3, thus ending the flap folding process.

When the length of the upper flaps A4, A4 is greater than the height of the content B and accordingly the end of the upper flaps A4, A4 extends below the bottom surface B5 of the content B, the inner ends 5a, 5a of the folding guides 5, 5 protrude along the bottom surface B5 of the content B by the action of the weights 5c, 5c after the content B has moved upward beyond the guides 5, 5. At this position, the latches 7 and protrude respectively along the right and left ends of the bottom surface B5, and to the vicinity of the center of the bottom surface B5. When the content B is supported by the latches 7, 8 the mounting surface 2a of the elevator 2 lowers, and the inner ends 5a, 5a of the folding guides 5, 5 protrude under the action of the weights 5e, 5c as shown in Fig. 18 (e), to thereby fold the forward ends of the upper flaps A4, A4 along the bottom surface B5 of the content B, and at the same time to attach the adhesive tapes C2, C2 applied on these forward ends, to seal the content B, thus ending the flap folding process.

When the wrapping changeover switch S3 is operated to select up-folding wrapping, the adhesive tapes C2, C2 protrude from the forward ends of the lower flaps A3, A3 as shown in Fig. 19 (a). After the completion of the initial wrapping process, and the side flaps A2 are folded inward by the side-folding guides 1. Then the transfer means 3 moves forward to move the content B along the mounting surface 2a of the elevator 2, and the upper flaps A4, A4 hit against the downfolding guides 6, 6 as shown in Fig. 19 (b), and are folded along the open sides B1, B1 of the content B. Thereafter as the content B is carried, the lower flaps A3, A3 hit, at their base ends, against the inclined sides 4a, 4a of the up- folding guides 4, 4 and are folded up. The up- folding guides 4, 4 rise to fold up the lower f laps A3, A3 along the open sides B1, B1 as shown in Fig. 19 (c), and subsequently the elevator 2 moves upward.

Accordingly, as shown in Fig. 19 (d), the upper surface B4 of the content B rises to the same level as the lower surface of the folding guides 5, 5, when the elevator 2 temporarily stops rising. Then, the folding guides 5, 5, as shown in Fig. 19 (e), protrude along the upper surface B4 of the content B, thereby folding the forward end of the lower flaps A3, A3. At the same time the adhesive tapes C2, C2 applied on the forward ends are attached for sealing on the upper surface B4, thus finishing the flap folding process.

After the flap folding of the content B, the wrapping of the following content B is started. The elevator 2 begins descending and the folding guides 5, 5 move away from each other. Even although the elevator is lowered, the content B, being supported by the latches 7, 8, will not go downward. When the following content B can be initially wrapped without the proceding content B having to be removed in that the preceding content B is stacked on the latches 7, 8.

Furthermore, when the size of the wrapping sheet A has been changed, the control circuit 10 automatically changes the length of the wrapping sheet A to be fed out by the sheet feed mechanism 12, on the basis of data entered by the input means 9.

When the outside dimensions including height of the content B have been changed, the control circuit 10 will automatically change the length of the wrapping sheet A to be fed out by the sheet feed mechanism 12, on the basis of data inputted by the input means 9, and also will automatically change the amount of ascent and descent of the elevator 2 and the level of the up folding guides 4, 4. When the width of the content B has been changed, the control circuit 10 will automatically change the length of the wrapping sheet A to be fed out by the sheet feed mechanism 12, and will automatically move the reference guides 15 and the body wrapping guides 14, 14 in the same direction to change the distance between these guides. Furthermore, when the length of the content B has been changed, the up- folding guides 4, 4 and the folding guides 5, 5 will be moved in the lateral direction, thus automatically changing the distance between these guides.

In the embodiment described, one wrapping sheet A was separated from a pile of wrapping sheets A and is fed onto the elevator 2, but it should be noted that the present invention is not limited to this embodiment and in another embodiment, a wrapping sheet wound in a form of roll may be cut to a specific length and supplied onto the elevator 2.

Furthermore, the forward ends of the upper flaps A4, A4 or the lower flaps A3, A3 are sealed with the adhesive tapes C2, C2 that had previously been applied, but the present invention is not limited thereto and the adhesive tape may be attached in the course of, or after, the wrapping process, or the flaps may be attached by the use of paste other than the solid adhesive tape. Furthermore, the wrapping sheet A was folded up in a form of U letter for body wrapping along both sides B2, B2 and bottom surface B5 of the content B while moving downward on the elevator 2, but the present invention is not limited thereto and the body wrapping may be performed by hitting the upper surface B4 of the content B against the wrapping sheet A supplied to a position above it, by raising the elevator 2, so that the wrapping sheet A folds down into the form of an inverted U shape along both sides B2, B2 and upper surface B4 of the content B. Furthermore, the folding parts 1b were lowered with the rotation of the side-folding guides 1 by the use of the support shaft 1c which forms a spiral guide path as a guide moving means, but the present invention is not limited to the embodiment explained above and the folding parts 1b may be moved upward with the rotation of the side-folding guides 1 by the use of the guide moving means especially in the case of up folding wrapping wherein the upper flaps A4, A4 are folded first after the folding of the side flaps A2.

The present invention, having the construction described above, has the following advantages.

1. The side-folding guide approaches the side flap until the hitting part hits against the closed side of the initially wrapped content, to thereby press the sheet against the content near the base end of the side flap; subsequently, the middle part of the side-folding guide makes a quarter turn while pressing on the adjacent corner of the content. Thereby, the base end of the side flap is folded along the corner whilst it is pulled toward its forward end, and also is pushed against the open side of the. The side flaps, therefore, can be folded tight without swelling of the sheet. Therefore, as compared with the prior-art device in which the side-folding guide simply moves horizontally along the open side of the content to be wrapped, to fold the upper and lower ends of the side flap, the present invention has the advantage that if the content is initially wrapped loose or if a corner is chamfered to an oblique or circular form, stabilized side flap folding can be ensured and the whole of the overhang end can be folded tight along the side, thus improving the outside appearance as well as its commodity value. In addition, since the side-folding guides rotate in contact with the content to be wrapped, there is no necessity to provide a power source for turning the side-folding guides unlike the prior-art device which required power turning of the side-folding guides. Moreover, when no content is present, the side-folding guides will stop without a special changeover operation.

2. The folding part is moved either toward the lower flaps or the upper flaps by the guide moving means when the side-folding guides are rotating, and therefore the whole of the side flaps is pulled in the direction of the folding part, thus folding the side flaps while pressing the base end of the side flaps against the corner. It is, therefore, possible to fold the whole of the side flap tightly simply by folding one place in the vertical direction of the side flap, regardless of the height of the content. Therefore, as compared with the prior art wherein the side flap is folded at two places, upper and lower, by means of the side-folding guides, the present invention has the advantage that even when the height of the content has been changed, it is unnecessary to change the vertical size of the side-folding guides. Since the side-folding guides require no vertical size adjusting mechanism, the whole of the device can be simplified and minimized in construction.

3. The folding part is moved to either the upper or the lower end of the content by the guide moving means at the time of rotation of the side-folding guides, to thereby produce a horizontal folding line in either the lower flap or the upper flap. It is, therefore, possible to effect exact folding of the lower or upper flap.

4. The content is transferred in the lateral direction by the transfer means to cause the base end of the lower or upper flap to hit against an inclined side of guide moving means located in the direction of movement of the transfer. With both side flaps being pulled in the direction of movement of the guide moving means, only the base end of the lower flap or the upper flap disposed in this direction of movement is folded, partly producing a folding line between these flaps. Therefore the remaining lower and upper flaps are folded, holding the folded state of the side flaps. When the remaining lower and upper flaps are folded, the whole of the flap can be folded tight without loosening the side flaps previously folded.

5. The contact-rotation timing of a pair of side folding guides in relation to both side flaps of each overhang end is timed, so that the middle parts of the side flaps, when folded along the open side of the content, overlap. At the same time, the folding of the lower and upper flaps is prevented. Therefore even in the case of overlap folding, the lower flap and the upper flap can be folded in a trapezoidal form without the side flaps interfering with each other. Therefore, as compared with prior-art devices which cannot perform overlap folding, in the present invention, the upper and lower flaps can be folded smoothly without deteriorating the outside appearance. Besides, both side flaps can be folded along the open sides. The flap folding device of the present invention, therefore, ensures easy wrapping in a wide range of applications.

6. The hitting parts of the two side-folding guides which are at one side of the content and which in a waiting position lie on straight lines extending nearly parallel with the closed side of the initially wrapped content, hit against each closed side simultaneously, thereby correcting any mis-mounting position of the content in a direction relative to the lateral direction, and when the side folding guides make a quarter turn simultaneously onto the open sides of the content, they correct any mis-mounting position of the content relative to the transfer direction. It is, therefore, possible to properly set the content in the mounting position. As compared with prior-art devices in which each side-folding guide moves horizontally along the parallel open side of the content after hitting against the side flap, the present invention has the advantage that the content will not move out of the mounting position as a result of the shock of the hitting of the side folding guides against the side flaps, even when the content is of light-weight and is easy to move. Also, if the content is off the mounting position, the positional shift of the content can be absorbed, preventing a defective folding of the side flap. Further, the positional shift of the content can be prevented by changing the timing of the hitting of side-folding guide on the side flap.

7. The reversion holding means is operated by contact-engagement with the side-folding guide, thereby forcing the hitting part which is off the content, to turn reversely in the reverse direction of folding of the side flap. As compared with prior-art devices in which the side-folding guide is reversed by means of an elastic member such as a spring, the device of the present invention insures reliable forced reversion of the side-folding guide, and it will not be subject to malfunction such as might occur as a result of failure of the elastic member as a result of long use or catching of the side-folding guide on the flap.

8. The projection length of each protruding end is computed from the inputted length of the wrapping sheet and the length of the content, and a comparison is made of the result of the computation with half of the width of the open side of the content to decide whether normal folding or overlap folding is required. The operation of the elevating means is controlled in accordance with the result of this decision, and the contact position of the side flap and the side folding guide to the optimum normal or overlap folding position is automatically calculated. It is, therefore, possible to perform normal folding and overlap folding without adjusting the side folding guide regardless of a change in size of the content and the wrapping sheet by inputting numerical values.

9. The side flap-to-side-folding guide contact position is automatically adjustable to the optimum normal or overlap folding position by moving the level of the elevator with the content thereon, by the control means. It is, therefore, unnecessary to adjust the side-folding guide. Therefore, as compared with prior-art devices which require adjustment movement of the side-folding guide when the height of the content has been changed, the present invention requires no side-folding guide adjusting mechanism and accordingly results in simplified construction of the device as well as reducing the size of the device.

10. The end-of-folding position of the guide for the lower flap or upper flap to be folded first after the side flap is controlled by the control means. That is the end-of-folding position of the content can be changed according to whether normal folding or the overlap folding is involved. In the case of the overlap folding, the lower flap or the upper flap can be folded without the forward end of the guide contacting the folding line of the upper or lower flap.

11. After folding of both side flaps by the side folding guide, the content can be horizontally transferred by the transfer means along the transfer path when equipped with no down-folding guide, and folding up the lower flap by the up-folding guide is effected. Subsequently, the content is carried upward on the elevator until the upper flap hits against the folding guide. Then the folding guide is projected along the bottom surface of the content, to thereby fold down the upper flap against the outside of the lower flap, and its forward end is folded in against the bottom surface of the content. Alternately, the content with both side flaps folded is horizontally transferred along the transfer path which is equipped with the down-folding guide, thus folding down the upper flap and then folding up the lower flap on the outside of the upper flap by the up-folding guide. Almost simultaneously, the content is moved upward on the elevator, in the course of which the folding guide is protruded along the upper surface of the content to thereby fold the forward end of the lower flap against the upper surface of the content. It is, therefore, possible to perform both down and up folding wrapping in one machine.

Therefore, as compared with prior-art devices having only a special machine for either down folding wrapping or up folding wrapping, the present invention provides one device capable of selectively performing both down folding wrapping and up folding wrapping, improving usability of the device. At the same time, it is possible to fold down one of the overhang ends and fold up the other overhang end. Besides, the whole body of the device can be made small in size as compared with the prior art device.

Claims (14)

1. A wrapping machine with a flap folding device for folding the protruding ends of a wrapping sheet of kraft or the like paper, after it has been wrapped around an approximately rectangular item referred to as the "content", said folding device having a pair of side-folding guides (1) which move toward, and away from, both side flaps (A2) at each overhang end (A1) of the wrapping sheet (A) which protrudes in a square cylindrical form from an open side (B1) of the content (B) on the same plane as said open side (B1), for folding said side flaps (A2) inward along said open side (B1) of said content (B) and thereafter a lower flap (A3) and an upper flap (A4) in order, at the remaining overhang ends along said open side (B1) of said content (B), said flap folding device being characterised by an elevating means (2) for time shifting the contact-rotation between said pair of side folding guides (1) and both of said side flaps (A2), and elevating either one of said content (B) and said side folding guides (1), an input means (9) for variably inputting the width (W) of each open side (B1) of said content (B), the length (L) intersecting said width, the height of the content, and the length (SL) and width of the wrapping sheet (A), a computing means (10) for computing the overhang length of each overhang end (A1) of said wrapping sheet (A) on the basis of data outputted from said input means (9), a comparing means (10b) for comparing a result of this computation with half of the width (W) of said open side (B1) and a control means (10c) for controlling operation of a guide moving means in accordance with the result of computation.
2. A wrapping machine as claimed in claim 1, wherein said elevating means (2) is an elevator (2) of which the level, when loaded with a content (B) wrapped with the sheet (A), is controlled by said control means (10c) and said side folding guides (1) are fixed in a vertical direction.
3. A wrapping machine as claimed in claim 2, wherein a lower or upper flap guide (4, 6) for folding said lower or upper flap (A3, A4) subsequent to side flap folding is so disposed as to be able to reciprocate in a vertical direction along said open side (B1) of said content (B), and wherein the control means (10c) is adapted to control an end-of-folding position of said guides (1).
4. A wrapping machine as claimed in claim 1, said flap folding device being characterised by a transfer means (3) disposed to horizontally transfer the content (B) in a transfer path (3a) along the upper surface of an elevator (2) forming the elevating means, when in a lowered position, said side folding guides (1) being arranged to hit against both side flaps (A2) at each overhang end, for folding said side flaps (A2) inward along said open side (B1) of said content (B), and including up-folding guides (4) which hit against a lower flap (A3) and fold said lower flap (A3) upward along said open side (B1), protruding folding guides (5) disposed above said up-folding guides (4) adapted to contact said open side (B1) of said content (B) as it is ascended by said elevator (2), such that said guides (5) can protrude out along the bottom (B5) or upper (B4) surface of said content (B) and down-folding guides (6) disposed between said side folding guides (1) and said up-folding guides (4) which are arranged to hit against an upper flap (A4) and fold it down along said open side (B1), said down-folding guides (6) being adapted to be reciprocated or moved out of said transfer path if not needed..
5. A wrapping machine as claimed in claim 1, wherein the flap folding guide (1) comprises a hitting part (1a) facing but spaced from a closed side (B2) of said content (B), and a folding part (1b) opposite said flaps (A2), said parts (1a),(1b) being to opposite sides of a middle position at which there is a center of rotation (1c) which lies close to the said open side (B1) of said content (B) so that said side-folding guides (1) can rotate to fold said side flaps (A2), and, with said side flaps (A2) folded, will move in contact with said open side (B1) of said content.
6. A wrapping machine as claimed in claim 5, wherein said side-folding guides (1) are disposed between upper (B4) and lower (B5) ends of said content (B), and a guide moving means (1c) is provided to move said folding part (1b) toward either one of said lower flap (A3) and said upper flap (B4) with the rotation of said side folding guides (1) toward folding said side flaps (A2).
7. A wrapping machine as claimed in claim 6, wherein said guide moving means (1c) moves said folding part (1b) toward said lower flap (A3).
8. A wrapping machine as claimed in claim 7, including an up-folding means (1e) connected to the side folding guides (1) for folding said lower flap (A3) upward along said open side (B1) of said content (B) at the time of side flap folding
9. A wrapping machine as claimed in claim 8, wherein, as the up-folding means (1e) rotates during side flap folding, an inclined, movable surface (1e) thereof is gradually raised upright so that said inclined movable surface (1e), which is connected above said folding part (1b) contacts said open side (B1) of said content (B).
10. A wrapping machine as claimed in claim 6, wherein said guide moving means (1c) moves said folding part (1b) as far as either the upper (B4) or lower (B5) end of said content (B).
11. A wrapping machine as claimed in claim 10, further comprising a transfer means (3) for transversely transferring a content (B) with side flaps folded; and inclined sides gently inclined toward the center in the vertical direction of said open sides as they go downstream in the direction of transfer; said inclined sides being disposed slightly protruding from a transfer surface of said content toward the center in the vertical direction of said open side of said content.
12. A wrapping machine as claimed in claim 5, wherein a pair of side folding guides (1) are disposed opposite to a middle position in the vertical direction of said content (B), and the timing of the contact-rotation between the folding guides (1) and the side flaps (A2) is adjustable.
13. A wrapping machine as claimed in claim 5, wherein four side folding guides (1) are provided opposite to said side flaps (A2) on said overhang ends (A1), said side folding guides (1) being disposed on two straight lines which are nearly parallel to the closed sides (B2) of the content (B) such that said side folding guides (1) are spaced from the content (B) so that the hitting parts (1a) of two aligned side folding guides (1) at each closed side of said content (B) simultaneously hit against the adjacent closed side (B2).
14. A wrapping machine as claimed in claim 5, further comprising a reversion holding means (1g) for forcing said hitting part (1a) to turn in a reverse direction and for holding said hitting part (1a) spaced from said content (B), said reversion holding means (1g) being operated by contact-engagement with said side folding guides (1) in the folding position.

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