JP4580599B2 - Synthetic resin cap weakening line forming device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a line of weakness forming equipment of synthetic resin cap having a tamper evident band.
[0002]
[Prior art]
Conventionally, in the production of a synthetic resin cap (hereinafter simply referred to as a cap) having a tamper evident band (hereinafter referred to as a TE band), a weakening line formed between the TE band and the skirt wall is post-processed by a cutter. As a weakening line formation method in the case of forming, in general, a through slit that penetrates the thickness of the skirt wall is intermittently formed at the lower part of the skirt wall, leaving a portion that becomes a bridge portion in the circumferential direction, and then left. A method has been proposed in which the bridge portion is cut by half the thickness of the bridge portion to make the bridge portion thin and easy to break (see, for example, Japanese Patent Publication No. 2-3313). As another method, only a plurality of longitudinal ribs are formed by continuously forming a plurality of longitudinal ribs on the inner peripheral surface of the lower part of the skirt wall, and continuously forming slits over the entire circumference of the skirt wall leaving the ribs. There is known a method in which a weakening line is formed by remaining as a bridge.
[0003]
In either method, the cap is rotated while being revolved from above and below, and one or two cutters that form a slit that penetrates the skirt wall are arranged on the outer periphery of the revolving path, and the cap rotates once. In the meantime, intermittent or continuous slits are formed over the entire circumference. Therefore, it is necessary to cut the cutter by the thickness of the TE band at once. Therefore, particularly in the case of a thick TE band, there is a drawback that the cutting resistance is large, the blade of the cutter undulates, and the cutting edge is wavy. In addition, whitening and cracking of the resin may occur due to the impact of cutting. In addition, there is a problem that the cap slips due to the cutting resistance and becomes idle, making it impossible to form a good slit.
[0004]
In particular, in the case where a cap made of different materials such as polyethylene is attached to a synthetic resin bottle such as a PET bottle, in order to recycle resources by separating the TE band from the bottle for easy collection and collection, The TE band has been proposed to be easy to remove by making a longitudinal cut, but since such a TE band is thick, the resistance at the time of forming the circumferential slit is much larger, and the above problems Has become more prominent. For this reason, for example, a cap having a thick part and a thin part in the TE band is formed so as to have an overlapping part in the thickness direction of the TE band in order to make the vertical cut in the TE band inconspicuous. Resin whitening and cracking occurred in the part, and there was a problem of poor yield.
[0005]
[Problems to be solved by the invention]
The present invention was devised in view of the above circumstances, and in the manufacture of a cap with a TE band, when the weakening line formed between the TE band and the lower end of the skirt wall is formed by post-processing with a cutter, the cutter swell of incision occur because the cut resistance is large, the resin whitening and cracking, and to provide a line of weakness forming equipment of synthetic resin cap capable of preventing the occurrence of the phenomenon of idling or the like of the cap during rotation Objective.
[0006]
[Means for Solving the Problems]
The weakened line forming device for the synthetic resin cap of the present invention is the weakened line forming device for forming the weakened line that partitions the lower end of the skirt wall of the synthetic resin cap and the tamper evident band by post-processing, On the outer periphery of the turret body, a plurality of cap holding devices that hold the caps one by one from the top and bottom and rotate the caps according to the rotation of the turret main body are arranged at equal intervals, and the path through which the cap holding devices revolve A preliminary cutter assembly having a preliminary cutting cutter and a main cutter assembly having a main cutting cutter are sequentially arranged, and the preliminary cutting cutter and the main cutting cutter are provided. The cross section thickness of the preliminary cutting end base of the preliminary cutting cutter is Cross-sectional thickness and equal to or of the cutting completion base of use cutters, and wherein the cross-sectional thickness of the cutting ends the base of the cutting cutter is slightly greater relationship than cross-sectional thickness of the pre-cutting finished base of the pre-cutting cutter Could be solved by technical means.
[0007]
The configuration of the cap holding device is not particularly limited. As one form, the cap holding device includes a cap receiving portion and a cap pressing portion. The cap receiving portion is driven up and down by a fixed cylindrical cam, and the lifter shaft. The cap support turntable is supported by a cap holding pressure adjusting spring so as to be rotatable with respect to the lifter shaft.
[0008]
Further, the cap pressing portion can be configured by having a cam that adjusts the cutting depth of each cutter on a rotatable spindle that holds the cap top surface with the cap receiving portion.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 shows an arrangement state of the weakening line forming device in the synthetic resin cap manufacturing line, and FIG. 2 is a cross-sectional view taken along the line II in FIG. 1, showing the main part of the weakening line forming device.
In FIG. 1, 1 is a weakening line forming apparatus, 2 is a supply turret for supplying a cap to the weakening line forming apparatus, and 3 is a discharge turret. Reference numeral 4 denotes a flap bending device that bends the flap of the molded cap inward. In this cap manufacturing line, the cap is supplied to the flap folding device 4 through a conveyor device (not shown) after molding, and the flap piece is folded inside the TE band by the device, and then a weakening line is formed through the supply turret 2. The weakened line forming device 1 forms a slit in the circumferential direction at the boundary between the TE band and the skirt wall. The cap after the formation of the slit in the circumferential direction is sent to the inspection device or the like via the discharge turret 3, and the acceptable product is sent to the packaging device for shipping.
[0011]
As shown in FIG. 2, the weakening line forming apparatus 1 according to the present embodiment holds the cap one by one on the outer peripheral portion of the turret body 10 composed of the lower rotating plate 8 and the upper rotating plate 9 that rotate integrally. In addition, a large number of cap holding devices 13 that rotate the cap as the turret body rotates are arranged at equal intervals, and two pre-cutting cutter assemblies 11 ₁ face the path along which the cap holding device revolves. 11 ₂ and two main cutting cutter assemblies 12 ₁ , 12 ₂ are sequentially arranged. The cap holding device 13 includes a cap receiving portion provided in the lower jaw portion 14 of the pocket of the turret main body 10 and a cap pressing portion provided in the upper jaw portion 15. In the cap receiving portion, a lifter shaft 17 is fitted to a sleeve 16 fixed to the lower jaw portion 14 so as to be slidable in the axial direction, and a cap support turntable 18 is provided on the top of the lifter shaft 17. The cap support turntable has a base plate 19 on which the cap top surface is placed with the cap inverted, and a shaft portion 20 extending downward from the center of the lower surface of the base plate, and the shaft portion is rotatably fitted to a bearing. The lower end lifter shaft 17 is positioned in a vertical hole 21 having a predetermined depth provided at the top. A spring 22 for adjusting the cap holding pressure is provided between the lower surface of the vertical hole and the shaft portion. A cam follower 24 that fits into a cylindrical cam 23 provided in a fixed portion of the apparatus main body is provided at the lower portion of the lifter shaft 17, and the lifter according to the cam shape of the cylindrical cam 23 as the turret main body rotates. The shaft 17 moves up and down, so that the cap support rotary base provided at the top of the lifter shaft moves up and down, and the cap is clamped with a predetermined clamping pressure with the cap presser.
[0012]
On the other hand, the cap presser portion is provided to hang down from the upper turntable 9 of the turret main body, and as shown in an enlarged view of the main part in FIG. 3, at the lower end of the spindle 25 that is rotatably provided on the upper turntable 9. A cap top wall engaging member 29 is attached. The cap top wall engaging member 29 is engaged with the inner surface of the top wall of the cap 50 rising on the cap support turntable 18, and the cap 50 is sandwiched between the cap support turntable 18. The cap top wall engaging member 29 is screwed into the lower end of the spindle 25, a screw hole is formed in the center thereof, and the lower end of the central portion is opened, and the cap top wall engaging member 29 is formed on the top wall of the cap. The bottom of the cap is uniformly pressed against the inner surface of the top of the cap by an annular portion so as not to come into direct contact with the hot water pool at the center of the inner surface, thereby preventing sliding rotation during cutting. The lower end surface of the annular portion is provided with a deformed lattice-shaped groove such as a lattice shape or a rhombus so as to more effectively engage with an anti-rotation protrusion formed on the inner surface of the top wall of the synthetic resin cap. Yes. The cap top wall engaging member 29 also serves as a backup member that backs up the lower end of the skirt wall when the cutter 40 forms a slit. A cam roller 26 and a gear 27 are provided in the middle of the spindle 25. The cam roller 26 engages with an eccentric roller cam 38 fixedly provided on the cutter mounting base 35 of the cutter device 30, and controls the cutting depth of the cutter by adjusting the amount of eccentricity of the eccentric roller cam. On the other hand, the gear 27 meshes with a large gear 28 provided in the fixed portion, and the spindle 25 rotates in accordance with the rotation of the turret body, whereby the cap support turntable rotates together with the cap. And rotate the cap.
[0013]
The cutter device 30 is composed of four sets of cutter assemblies including preliminary cutting cutter assemblies 11 ₁ and 11 ₂ and main cutting cutter assemblies 12 ₁ and 12 ₂ , and each cutter assembly is a rotation path of the turret body 10. Are supported by the support columns 33 arranged on the fixed frame 5 on the outer peripheral portion of the outer peripheral portion so that the distance can be adjusted. Each cutter assembly includes a cutter support base 34 fixed to the column, a cutter mounting base 35 supported on the cutter support base so as to be displaceable in the direction of the turret body, and a cutter blade chuck attached to the cutter mounting base 35. 37. The cutter mounting base 35 is slidably mounted on a linear guide 36 provided on the cutter support base 34, and engages with a chuck 37 for detachably fixing the cutter blade 40 and a cam roller 26 provided on the turret body. An eccentric roller cam 38 is attached, and a spring 39 for biasing the cutter mounting base 35 so that the eccentric roller cam 38 is always in pressure contact with the cam roller 26 is provided between the eccentric roller cam 38 and the cutter support base 34.
[0014]
The pre-cutting cutter blade 41 attached to the pre-cutting cutter assemblies 11 ₁ , 11 ₂ has a shape as shown in FIG. 4A and is attached to the main cutting cutter assemblies 12 ₁ , 12 _2. The cutting cutter blade 42 has a shape as shown in FIG. The cutting edge of the cutting blade for preliminary cutting and the cutting blade for cutting are both tapered at the tip of the cutting edge. However, as will be described later, the requirement for the preliminary cutting blade is approximately 40-60 of the thickness of the weakened line forming portion of the cap. % Of the cutting base of the cutter blade (that is, the thickness t _{1 of the} base end of the pre-cutting) when cutting to% (that is, when the pre-cutting is finished) can be cut well without waviness of the cutting edge. In addition, it has an optimum thickness that can be cut without giving a large impact or resistance. On the other hand, this cutting cutter blade cuts the remaining thickness, that is, 60 to 40% following the preliminary cutting, so that the shape is expanded at the same taper angle as the preliminary cutting cutter blade. Since the thickness of the base of the depth of cut when cutting the full thickness is too thick, it will give a large resistance to the weakened line forming part. The base portion, that is, the cross-sectional thickness t ₂ of the cutting end base portion is formed to be the same as or slightly larger than the thickness t ₁ of the preliminary cutting end base portion of the precutting cutter. The optimum values of the thicknesses t ₁ and t ₂ depend on the thickness of the portion forming the weakening line of the cap, and are not limited to specific values.
[0015]
From this point of view, in the present embodiment, the taper angle α and the height of the tip end of the thick synthetic resin cap employed in a normal bottle cap with a diameter of 28 mm are the same as the pre-cutting cutter 41 and the main cutting. The cutting cutter 42 is substantially the same, and α = 20 ° to 45 °, but the taper angle β of the taper portion is larger than the main cutting cutter, and the preliminary cutting end base portion of the preliminary cutting cutter 41 is set. The thickness t ₁ was selected to be in the range of 0.3 to 0.45 mm, and the thickness t ₂ of the main cutting end base of the main cutting cutter 42 was in the range of 0.3 to 0.5 mm. In this embodiment, both cutter blades are configured such that a tapered portion of another angle continues from the tip of the blade tip, but the portion continuing from the tip of the blade tip does not necessarily need to be formed in a tapered shape. the value of t ₁ and t ₂ may be formed at equal thickness so that the above-mentioned range. If the values of t ₁ and t ₂ are smaller than the above range, the edge of the blade is likely to be swelled or broken, and if it is larger than the above range, the cutting resistance is increased, causing resin whitening or cracking. .
[0016]
In this way, by increasing the taper angle of the taper portion of the preliminary cutting cutter and increasing the thickness of the blade edge, the blade edge can be undulated and can be cut well, and the waviness of the cut edge can be prevented. Even if the cutting edge of the pre-cutting cutter is thickened, it cuts only halfway through the wall thickness, so that the impact on the thin wall portion is small. In this cutting where resistance increases, the cutting angle can be reduced by reducing the taper angle of the cutter and reducing the thickness, thereby eliminating whitening, cracking and waviness of the thin part more effectively. be able to.
[0017]
The weakening line forming apparatus of the present embodiment is formed as described above, and the cap 50 is placed on the base plate 19 of the cap support turntable 18 that rotates together with the turret body 10 from the supply turret 2 at the cap supply position. Supplied. With the rotation of the turret body, the lifter shaft 17 is raised by the cylindrical cam 23, and the cap ceiling wall engaging member 29 is fitted to the cap inner surface on the base plate 19. The cap top wall 58 is held between the base plate 18 and the base plate 18. The clamping pressure at that time must be a holding force that prevents the cap from spinning around due to the cutting resistance when forming the circumferential slit, and the cushion of the spring 22 provided between the lifter shaft 17 and the cap support turntable 18. It is obtained by adjusting the amount (spring pressure). Therefore, a strong clamping pressure can be obtained by selecting a spring with a small cushion amount, and a clamping pressure can be reduced by selecting a spring with a large cushion amount.
[0018]
At the same time that the cap ceiling wall 58 is clamped by the cap ceiling wall engaging member 29 and the base plate 18, the rotational force of the spindle is transmitted to the cab support rotary platform 18, and the cap support rotary platform 18 also holds the cap. Rotates together. Therefore, while the cap rotates, the pre-cutting cutter assemblies 11 ₁ and 11 ₂ and the main cutting cutter assemblies 12 ₁ and 12 ₂ are arranged and pass through the positions, so that each has a predetermined cut thickness. The cutter set to become cut, and the circumferential slit is formed in two stages of the main cutting following the preliminary cutting of the circumferential slit. At that time, the cutter mounting base 35 is slidably attached to the cutter support base 34 via the linear guide 36, and the cutting pressure of the cutter is applied with a predetermined spring pressure by the spring 39, so that the cutting resistance is predetermined. When an unexpected situation that exceeds the value occurs, the spring 34 cushions, thereby preventing an accident such as damage to the cutter blade.
[0019]
FIG. 7 shows the order of the slit forming process on the cap 50, (a) to (b) show the preliminary cutting process, and (c) to (d) show the main cutting process. In preliminary Kattengu step (a), the preliminary cutting of the half as shown by arrow a by the preliminary cutting assembly 11 _1. Subsequently, the preliminary cutting of the remaining half at the preliminary cutting assembly 11 ₂ in the preliminary cutting step (b). The depth of cut in the preliminary cutting process is about 40-60% of the wall thickness. If the cutting depth of the preliminary cutting is out of the above range, the effect of distributing the resistance separately for the preliminary cutting and the main cutting is reduced. Desirably, it is made into the 45 to 55% range where this effect is exhibited most. The start position of the preliminary cutting is arbitrary, but if the end position of the preliminary cutting overlaps with the thin part, the thin part tends to be whitened or cracked by the impact at the end, so the preliminary cutting end position is the TE band. It is desirable not to be in a position where there is a vertical cut (that is, a position where a thin portion is present).
[0020]
When pre-cutting process is completed, the remaining thickness portion of the present cutting assembly 12 ₁ Preliminary cutting in the cutting step (c), was cut in the range of 180 ° as indicated by the arrow c, followed by the cutting assembly In the main cutting step (d) according to 12 _2, the remaining remaining thickness indicated by the arrow d is cut. In this case, in the present embodiment, the preliminary cutting cutter assemblies 11 ₁ and 11 ₂ and the main cutting cutter assembly are arranged so that the main cutting start position and the end position are shifted from the preliminary cutting start position and the end position by 180 °. The arrangement positions of 12 ₁ and 12 ₂ are adjusted. However, the actual cutting start position and end position are not necessarily limited to those in the present embodiment, and the arrangement thereof is arbitrary, but it is desirable that the position be shifted from the preliminary cutting end position.
[0021]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various design change is possible within the range of the technical idea. For example, in the above-described embodiment, the preliminary cutting process and the main cutting process are each performed by two cutters. However, the present invention is not necessarily limited thereto, and any cutting process may be used as long as the cutting depth is divided into two stages. Each of them can be performed by one cutter or two or more cutters.
[0022]
【Example】
4 and 5, the TE band 52 can be easily removed from the bottle mouth after opening, and the TE band 52 has a complete vertical cut in the vertical direction so that the bottle and cap can be separately collected and easily recycled. 53 is formed. However, when a cut is simply formed in the vertical direction, the crevice is opened and the bottle mouth is exposed in a state where the bottle is capped, resulting in a poor appearance. In order to avoid this, in the cap of the present embodiment, the vertical cut 53 is shifted in the circumferential direction through the stepwise circumferential vertical cut 56 and the cut inlet 54 and cut outlet 55 in the thickness direction of the TE band 52 are shifted. By providing an overlapping portion in the thickness direction, the bottle mouth is prevented from being exposed directly from the vertical cut. Therefore, the TE band in the cap of the present embodiment is thick as a whole, but the longitudinal slit forming part is a thin part, so the circumferential slit is cut by the conventional cutting method and apparatus. Then, whitening and cracking were likely to occur in the thin portion of the vertical cut forming portion. In addition, the thickness of the TE band of this cap was 1.8 mm, and the thickness of the thin portion of the longitudinal cut portion was 0.25 to 1.0 mm.
[0023]
5 and 6, reference numeral 51 denotes a skirt wall of the cap body, and a screw 57 is formed on the inner peripheral surface thereof. The top wall 58 is provided with a plurality of fine protrusions 59 to prevent slippage between the cap top wall engaging member 29 and the cap due to the resistance of the cutter when the slit is formed, thereby increasing the frictional force. ing. Reference numeral 60 denotes a circumferential slit that forms a TE band, and has a plurality of minute bridges 61 protruding inward. A plurality of narrow ribs in the vertical direction are formed at predetermined intervals on the inner peripheral surface of the portion forming the weakening line, and when forming the circumferential slit by post-processing from the outer peripheral surface, By cutting so as to leave a rib, the rib becomes a breakable micro bridge 61 protruding from the inner peripheral surface. 62 is a flap that is locked to the neck of the bottle mouth when the cap is opened to prevent the TE band from rising.
[0024]
A TE-band circumferential direction weakening line was formed on the cap having the above-described configuration by the weakening line forming apparatus of the above embodiment. As a result, it was possible to disperse the cutting resistance in the preliminary cutting and the main cutting, and no occurrence of whitening and cracking of the thin wall portion was observed. Further, the undulation of the cutter disappeared, and the phenomenon that the slit edge was undulated was not observed at all. Furthermore, the slit can be formed satisfactorily without cutting the cap due to the cutting resistance during cutting, and the usefulness of the weakening line forming method and apparatus according to the present invention was confirmed.
[0025]
【The invention's effect】
As described above, according to the weakening line forming method and apparatus of the synthetic resin cap of the present invention, the cutting resistance can be divided into two stages so that the cutting resistance can be dispersed. Even with a thick TE band in which a longitudinal slit is formed, an increase in cutting resistance due to thickening can be suppressed, and whitening and cracking of a thin-walled portion or the like can be completely prevented. Further, the undulation of the cutter is eliminated, and the slit is not undulated, so that the yield of manufacturing the cap can be increased and the life of the blade edge can be extended. Furthermore, the slit can be formed satisfactorily and reliably without the cap being idle due to the cutting resistance during cutting, and a high-quality cap can be obtained. Moreover, the synthetic resin cap weakening line forming apparatus according to the present invention can be easily applied without greatly improving the conventional cap manufacturing apparatus.
[Brief description of the drawings]
FIG. 1 shows an arrangement state of weakening line forming apparatuses according to an embodiment of the present invention in a synthetic resin cap production line.
FIG. 2 is a cross-sectional view taken along the line II in FIG. 1, showing the main part of the weakening line forming apparatus.
FIG. 3 is an enlarged view of a main part in FIG. 2;
4A and 4B show a cross section of a cutter blade according to an embodiment of the present invention, in which FIG. 4A is a preliminary cutting cutter blade, and FIG. 4B is a main cutting cutter blade.
FIG. 5 is a partial cross-sectional front view of a cap in the embodiment.
FIG. 6 is a bottom view thereof.
FIGS. 7A to 7B are preliminary cutting steps, and FIGS. 7C to 7D are process diagrams showing the main cutting step. FIGS.
[Explanation of symbols]
1 weakening line forming apparatus 2 supply turret 3 discharge turret 10 turret body 11 _1, 11 ₂ preliminary cutting knife assembly 12 _1, 12 ₂ cutting knife assembly 13 cap clamping unit 17 lifter shaft 18 cap support turntable 22 Spring 23 Cylinder cam 25 Spindle 26 Cam roller 29 Top wall engaging member 30 Cutter device 34 Cutter support base 35 Cutter mounting base 37 Cutter blade chuck 41 Preliminary cutter 42 This cutter 50 Synthetic resin cap 52 TE band 53 Vertical cut 56 Circumferential vertical cut 59 Protrusion 60 Circumferential slit (weakening line)

Claims (3)

A weakening line forming device for forming a weakening line dividing a lower end of a skirt wall of a synthetic resin cap and a tamper evidence band by post-processing, and holding the caps one by one on the outer periphery of the turret body from above and below, and A plurality of cap holding devices that rotate the cap as the turret body rotates are arranged at equal intervals, and a preliminary cutter assembly having a preliminary cutting cutter and a main cutting face the path along which the cap holding device revolves. a cutter device the cutter assembly is formed by sequentially arranged set only be by having an iodine cutter, the preliminary cutting knife and the present cutting cutter, the cross section thickness of the pre-cutting finished base of preliminary cutting cutter, the This is the same as the cross-sectional thickness of the cutting base of the cutting cutter. Weakening lines forming apparatus characterized by cross-sectional thickness of the cutting completion base of potting cutter is slightly greater relationship than cross-sectional thickness of the pre-cutting finished base of the pre-cutting cutter. The cap holding device includes a cap receiving portion and a cap pressing portion, and the cap receiving portion includes a lifter shaft that is driven up and down by a fixed cylindrical cam, and a cap support turntable provided on the top of the lifter shaft. becomes, the cap supporting turntable is rotatably and weakening lines forming apparatus according to claim 1 which is supported via a spring for adjustment cap clamping pressure to the lifter axis. The cap pressing unit according to claim 1 or 2 on a rotatable spindle clamping the cap top surface of the cap and the cap receiving part, and having a cam roller to adjust the cutting depth of the cutters The weakening line forming apparatus according to 1.

Images