MXPA00012174A - Arrangement for removing the trimming portions of a plastics blow-moulded bottle - Google Patents

Abstract

The trimming portion removal system is coupled to a bottle neck trimmer unit 1 provided with a vertical and rotary cutting head 5,8, and comprises a removal device 8 built-in under the cutting head 5,8 and provided with means 9-13 for removing a surplus dome 2b previously trimmed from the bottle neck, and a collection subsystem 16-23 for collecting the successive trimmed domes 2b, in which subsystem a tray open 16 at the top and sliding horizontally under the head 5,8 collects each dome and a compressed air insufflator 18 takes it by way of a duct 19 to a hopper 22. The removing means includes an expanding fork 9 for retaining the trimmed blow-dome 2b on the cutting head 5,8. A proximity sensor 21 detects the passage of every dome 2b towards the hopper 22.

Description

CLIPPER OF THE NECK OF A BOTTLE MOLDED OF PLASTIC FIELD OF THE INVENTION The present invention relates to the finishing of a plastic bottle formed by blow molding a parison, and in particular with auxiliary operations outside the mold, for the removal of excess material from the neck portion.

BACKGROUND OF THE INVENTION US-5749275-A discloses an apparatus for trimming the mouth of the neck of a plastic bottle, which leaves an internal surface on the rim of the mouth, circular cut and concentric with the neck axis. This cut surface must also have a precise diameter, because it cooperates in the tight sealing of the bottle with the screw cap, which has an internal annular wall which, in contact with said cut-out surface, closes the mouth of the bottle. inside her. The cut of the flange is carried out by means of punching, once the remaining domes in the neck have been eliminated after the molding of the bottle. US-5787772-A discloses a method for trimming excess material on the neck of a vertically positioned molded plastic bottle, where a rotary cutting head, moves vertically on a carriage covering the dome of the bottle, and has a blade horizontal internal that in contact with the neck of the bottle rotates and eliminates the dome of the neck, extracting it later by means of a vacuum system from inside the cutting head. Here the cutting surface is horizontal and must not meet any requirement of concentricity, because the neck itself is cut horizontally, nor with the condition of a uniform cut surface and precise inner diameter.

BRIEF DESCRIPTION OF THE INVENTION The object of the present invention is a system for cutting the neck of a plastic bottle blow molded from a parison, as defined in claim 1. The plastic bottles whose neck is finished by the trimmer according to the invention, they come out of the mold with a surplus dome of the neck of the bottle, formed by two parts, the outer one being eliminated before the trimmer system. The part of the dome to be trimmed for the finish of the mouth of the neck of the bottle is an axial projection of the mouth of the neck, and it must be cut and extracted from the trimmer, at the same time as the finishing operation is carried out. The cut-out bottle is intended to contain foods such as water or milk, and it is required that after cutting the neck no piece or burr of plastic falls inside the bottle, whereby the trimmer comprises a device for extracting the cut dome attached to the cutting device, and cooperating synchronously with a collection system of the successive cupolas cut. The neck of the cut-off bottle shall be closed with a screw cap, and the mouth shall be internally sealed by a vertical inner ring of the cap, by means of a watertight seal. The trimmer thus makes a vertical cut of an inner surface in the radial rim of the mouth, which is perfectly circular and concentric with the neck, in a synchronized manner with a mechanism for gripping and centering the neck, and each of the cutting operations It has to result without any failure. The cutting device of the trimmer comprises a vertical rotating flat blade, which is axially displaceable, and an extraction device ejects the trimmed dome downwards, when the trimmed bottle has been displaced, and before the next one is positioned.

BRIEF DESCRIPTION OF THE DIBI 'JOS FIG. 1 is a sectional view of the trimmer system of the neck of a bottle according to the invention. FIG. 2 is a sectional view of the cutting device included in the trimmer of Figure 1. FIG. 3 is a sectional view of the cutting device of Figure 2, according to the line III-III.

FIG. 4 is a view of the device of figure 3, with the cupola of the neck cut away. FIG. 5 shows a partial section of the neck of a bottle finished with the trimmer of figure 1.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY With reference to Figures 1 to 3, the trimmer system 1 of the neck of a bottle or blow molded container 2 shown in Figure 5, comprises a feeder (not shown in the drawings) of the bottles 2 by means of a rotary spindle which the horizontally displaced, where each spindle fillet displaces a bottle 2 in its vertical position with the neck 2a to be trimmed upwards, a gripping mechanism 4 for gripping and centering the neck driven by a cam shaft 3, a cutting device 5 rotary coupled coaxially to a vertical drive shaft 6 with an axis of rotation E, supported on a fixed horizontal table 7, and an extraction device 8 coupled to the cutting device 5, cooperating with a collection system 9 of the successive cupolas cut out . In the bottle 2 (Fig. 1 and 5) after the molding process, there is a coaxial dome 2b attached to the neck by a horizontal radial flange closing the mouth of the neck 2a. The dome 2b is cut by making a circular cutting line 17, which leaves an inner surface 2c on the rim of the mouth perfectly circular and of precise diameter, and concentric with the neck. The cupola 2b cut out is then extracted from the cutting device 5 and ejected out of the cutting area, towards the collection system 9. Each bottle 2 to be cut is positioned in the cutting area under the cutting device 5, and the gripping mechanism 4 holds the neck 2a and centers it with respect to the axis of rotation E, by means of a pair of semicircular jaws 4a, whose shape is adapted to the contour of the neck 2a. The horizontal displacement of the jaws 4a for their closure against the neck 2a and their opening is synchronized with the cam axis 3 and with the actuation of the cutting device 5. The rotating drive shaft 6 is located above the table and is axially movable up and down, through a hollow bushing 11 that passes through the table 7. The cutting device 5 is located below the table 7, and has a central body 5a cylindrical joined to the drive shaft 6 and coaxial with it, and a flat and vertical cutting blade 10 fixed to the periphery of the central body 5a (Figure 3). The radial distance "r" of the cutting edge 10a to the axis E of rotation is equal to the radius of the finished inner surface 2c. The blade has the edge 10a protruding below the central body 5a, formed with a cutting edge profile facing the inner surface 2c of the mouth, in order that the cutting surface 2c is smooth and uniform. To cut the mouth of the neck, the drive shaft 6 descends and the edge 10a of the blade is inserted in the radial flange of the neck 2a, to a depth that exceeds for example 0.5 mm the thickness thereof, which is between 0.3 and 1 mm, while rotating at high speed while bottle 2 remains motionless. The blade 10 is supported (Figure 3) by the central body 5a and integral with it. A flat side rim 14 on the diametrically opposite side of the blade 10, has a projection 14a, the end of which is above the cutting edge 10a of the blade, and avoids the decentering of the dome 2b when the blade is inserted for cutting. With reference to figures 3 and 4, the device 8 for the extraction of the cupola 2b trimmed from the neck, comprises a retention member 8a of the dome, a support disc 12 concentric with the central body 5a and coupled with a bearing 20 , which in its upward displacement abuts a bushing 11 of the table, and an ejector plate 13 abutting the dome 2b in its downward displacement prior to cutting, and then ejects the dome 2b cut off and retained by the member 8a in an upward displacement. The retaining member 8a is shaft-shaped, and is partially housed in the lower end of the central body 5a of the cutting device. It is projected below the plate 13 ejector, and has a retaining fork 16 incorporated to receive the cupola 2b cut off when the cutting device 5 ascends and separates it from the neck 2a. The retaining fork 16 is formed, for example, with a spring wire that is clamped through the retaining member 8a, and has two downward converging tips that are introduced through the mouth of the dome 2b, and two opposing loins 16a that are compressed by entering inside the dome, and then expanded once cut off hold it against the ejector plate 13, and hoist it when the central body 5a starts its upward path. The retaining member 8a is coupled to the central body 5a by a pair of bearings 22 (Fig. 2), which prevent the rotational traction of the dome 2b during cutting, and the dome 2b is held immobile with the retaining fork 16 and inserted. The bearings 22 allow the rotation of the member 8a accompanied by the dome 2b once cut. The support disc 12 and the ejector plate 13 are connected to each other for simultaneous movement, by means of two guide axes 18 of the ejector plate, which cross the central body 5a parallel to the axis of rotation E, and are fixed to a support sleeve 21 , which is in turn movable on the central body 5a. When the cutting device 5 performs its downward displacement to trim the dome 2b, the ejector plate 13 abuts the dome 2b and the extraction device 8 is retained, while the cutting device 5 continues to descend. When the support disc 12 in its upward travel abuts the bushing 11, the cutting device 5 continues its upward movement, and the retention member 8a discharges the dome 2b, expelling it to the collection system.

Claims (2)

NOVELTY OF THE INVENTION CLAIMS

1. A system for cutting the neck of a plastic bottle blow molded from a parison, which removes an excess dome from the neck of the bottle, the neck being provided with a radial rim extended inwardly and with an external thread, comprising: a vertically movable rotary vertical drive shaft; means for positioning the bottles with the neck up and centered with respect to the displaceable vertical drive shaft, and to keep it there immobile; a cutting device having its drive synchronized with the positioning and centering means, provided with a cylindrical central body coupled coaxially to the vertical drive shaft, and a rotating cutting blade supported by said cylindrical central body, whose edge penetrates said rim of the neck and makes a circular cut at a radial distance relative to the central axis of said cylindrical body; a device for extracting the cut dome vertically displaceable AND coupled to the cutting device; wherein the trimmer system leaves an inner surface concentric to the radial flange of the neck, for sealing the bottle by means of a screw cap on the peripheral of the neck.

2. The trimmer system of claim 1, wherein the means for extracting the cut dome comprise means for retaining the dome coupled coaxially in a non-rotating manner with said central body of the cutting device, for its separation from the neck of the bottle. 3- The trimmer system of claim 1, wherein the vertically movable rotary drive shaft is located above a fixed horizontal table which is traversed in the vertical displacement, and the cutting device is located below the fixed horizontal table , and said extraction means comprise means for ejecting the cut dome that move relatively to the cutting device until finding a stop on the fixed table. 4. The trimmer system of claim 1, wherein the blade supported by the central body of the cutting device has a cutting edge profile for its penetration into the mouth of the neck on the cutting line, and oriented towards said radial surface of closure of the bottle, to leave a smooth and uniform surface. 5. A system for cutting the neck of a plastic bottle blow molded from a parison, which eliminates a surplus dome from the neck of the bottle, the neck being provided with a radial flange extended inwards and with an external thread, comprising: a vertically movable rotary vertical drive shaft; means for positioning the bottles with the neck up and centered with respect to the displaceable vertical drive shaft, and to keep it there immobile; a cutting device provided with a cylindrical central body coupled coaxially to the vertical drive shaft, and a rotating cutting blade supported by said cylindrical central body, which makes a circular cut on the radial shoulder of the neck; a device for extracting the cut dome coupled to the cutting device and axially displaceable therewith, provided with means for retaining the cupola cut for its separation from the neck of the bottle, and ejection means displaceable relative to the cutting device, for the withdrawal of the cut dome towards a collection system located under the cutting device; wherein the trimmer system leaves a concentric inner surface of the radial flange of the neck, for sealing the bottle by means of a screw cap on the periphery of the neck. 6. The trimmer system of claim 5, wherein said retention means of the cut dome comprise a retaining member coaxially coupled non-rotatably with said central body of the cutting device, and having built-in an elastic retaining fork. which is introduced inside the dome before the cutting operation. 7- The trimmer system of claim 5, wherein the vertically movable rotary drive shaft is located above a fixed horizontal table which is traversed in the vertical displacement, and the cutting device is located below the fixed horizontal table, and said means for ejecting the dome cut, comprise a support disc, and a ejector plate surrounding the cutting device and joined by vertical guides, which after the cutting operation make an upward stroke with the cutting device hoisting the cupola cut, so that the disc Support finds a stop cap on the fixed table by actuating the ejector plate of the cut dome.