MXPA98000383A - Machines for the production of receptacles of material plast - Google Patents

Abstract

The present invention relates to a machine for the production of receptacles of plastic material, comprising a frame and arranged on a guide track at least a heating device and a blow molding device, the receptacles are formed from preforms arranged in carriers that move on the guide track, the guide track includes in the heating device, a number of rows of preforms parallel to the direction of movement, at least twice as large as the number of parallel rows of preforms in the device blow molding, the heating device comprises a quantity of elongated shaped heating bodies arranged between two parallel rows of preforms and adapted to emit heating radiation on two opposite sides in the direction of the two rows of preforms, each heating body comprises a plurality of heating tubes with bidirectional carbon blade what are you superpuest

Description

MACHINES FOR THE PRODUCTION OF RECEPTACLES OF PLASTIC MATERIAL The present invention relates to a machine for the production of receptacles of plastic material, comprising a frame and, arranged along a path of glide, at least one heating device and a blow molding device, these receptacles are manufactured from preforms, arranged on carriers placed along the guide path. A machine of this type is described in Swiss patent No. 683,757, which comprises a guiding path on which carriers carrying a preform move, through various stages and production devices. The carriers and the preforms comprise a single row that moves at a particular speed. Since the heating of the preforms is a relatively long operation, the length of the guide path should be large enough to obtain adequate heating, which greatly increases the overall size of the machine or also the speed of the preforms throughout. of the whole circuit must be diminished as a result, which considerably reduces the production of the machine. The object of the present invention is to overcome these drawbacks and to provide a high production and low volume machine. This machine, according to the invention, is characterized for this purpose by the peculiarities of claim 1. Thus, while increasing the number of parallel rows of preforms in the heating device, in relation to the number of parallel rows along the rest of the circuit and particularly of the molding device, the production output can be very high, while the overall size of the machine decreases considerably. Preferably, the guide path comprises in the blow molding device a single row of preforms aligned in the direction of movement, while comprising in the heating device a number of parallel rows of preforms, comprised between two and twelve, preferably six. This results in an optimal setting of the heating time for the preforms, adapted to the duration of the blow molding or blow, which allows a high production with a short guide path, therefore with a reduced size of the machine. According to a preferred embodiment, the blow molding device comprises at least one row of n mold cavities, aligned parallel to the direction of movement, the guide path comprises, in the heating device, n rows of preforms parallel to each other. the direction of movement. Thus, the n preforms that leave the heating device can be loaded directly into the molding device with a single movement or transport cycle, which allows very reliable and sensitive production. According to a preferred embodiment, the guide path comprises a portion having a general configuration of U and a second portion that is connected by a straight line to the arms of the U. In this embodiment, the first portion comprises the device of blow molding, a device for loading the produced receptacles and a device for loading the preforms, the second portion comprises the heating device. The central free space of the machine is thus optimally used to heat the preforms contained in the heating device which also serves as a storage, which gives the optimum arrangement of the various devices of the machine. According to a preferred embodiment, each carrier comprises a plate mounted, slidably, on the guide path, each plate carries two supports, each adapted to receive a preform.

By this arrangement, the movement of the preforms is effected in a precise manner, not only in the heating device but also in the molding device.

Also, changes of transport direction are easily made. Preferably, the carriers are of generally rectangular shape and comprise, aligned along their longer length, two bearings, in which the supports are mounted and rotatably retained. These supports may preferably be constituted by tubular members comprising, at their upper end, an annular retaining element, in which the preforms are retained by their neck, these tubular members pass through the bearings and are provided at their lower end with a pinion, adapted to act in conjunction with the impulse device, arranged in the heating device, for effecting the rotation of the supports and preforms, the guide path comprises rails on which the supports rest, the bearings comprise grooves , adapted to act in conjunction with the rails, in order to be retained on the guide path. This construction ensures a very fast assembly of the set of carriers and the reliable operation of the general stages and production devices of the machine.

According to a particularly preferred embodiment, the heating device comprises at least one heating element of elongated shape, arranged between two parallel rows of preforms and adapted to emit radiation of heat on the two opposite sides in the direction of the two rows of the preforms. The heating of the preforms is thus achieved in an effective manner, while considerably reducing the consumption of energy. Preferably, each heating body comprises a plurality of carbon heating tubes, superposed in bidirectional form. These heating tubes are particularly well suited for the machines in question and ensure efficient, regular and very economical heating. The heating device comprises, in a preferred manner, a number of heating bodies between one and six, preferably three, these heating bodies are arranged parallel to each other, each heating body being disposed substantially in the middle of the two preforms carried by each carrier The heating device can also work in parallel with a large number of preforms, which ensure the high production of the machine, while making significant energy savings.

According to a favorable embodiment, the heating body or bodies are movably mounted relative to the frame of the machine to be moved from an active position, in which they are arranged substantially facing the preforms, to an inactive position , in which they are spaced from the preforms. During interruptions in production, the preforms are damaged by overheating. This construction avoids this great inconvenience and gives the machine a reliable operation. Other advantages will appear from the characteristics indicated in the dependent claims and from the description of the invention which follows, in greater detail, with the help of the drawings, which show schematically and, as an example, a modality and modifications thereof. Figure 1 is a perspective view of the mode of the machine. Figure 2 is a schematic plan view of this embodiment. Figure 3A shows the heating bodies of a conventional heating device. Figure 3B shows the heating bodies of the heating device used in the present invention.

Figures A and 4B are front views of the heating device, respectively in the inactive and active positions. Figure 5 is a longitudinal cross-sectional view of the heating device in the active position. Figure 6 is a cross-sectional view through a carrier, whose supports and preforms are driven in rotation in the heating device. Referring to Figures 1 and 2, the machine for producing receptacles of plastic material comprises a frame 1, on which different devices and members of the machine are mounted in a modular manner. The preforms 2 for the receptacles to be produced, are supplied by means of a double rail 3 (Figure 1), comprise a loading device in inverted form, in which the preforms are inverted and disposed with the neck down in the supports 7 carried by the carriers 8, each carrier has two supports 7. The preforms 2 are then heated in a heating device 10 and taken to a stretching-blowing device 12. After their formation, the receptacles are raised from the support 7 in a discharge device 14 in inverted form, from which they can be packaged for future use or taken to stations for sterilization, filling, labeling, packing, etc. The empty supports 7 carried by the carriers 8 are then taken to the loading device 5 for the preforms. The carriers 8 are constituted by plates 16 of elongated rectangular configuration, with rounded ends, comprising the holes 17 in which the supports 7 are maintained. The plates 16 rest laterally on a guide track 20, comprised of two lateral rails 18, 19, which touch each other. This guide track comprises two distinctive parts 21, 22. A first part 21 comprises the outlet 23 of the heating device 10, the stretching-blowing device 12, the discharge device 14 and the connection path 24 towards the loading device 5 and the device for loading the preforms 2. In this first portion 21, the plates 16 touch each other by their rounded ends and are aligned with each other forming a single row of supports 7 and the preforms 2. On the contrary, in the second part 22 of the guide track 20, the plates 19 are in contact by their long sides and form three rows of parallel plates, here six parallel rows of supports 7, the two supports 7 of each carrier 8 are aligned in a direction perpendicular to the direction of movement of the carriers. Of course, the number of parallel rows of the carriers 8 may be less than or greater than three, according to the uses and the size of the machine. This part 22, however, will comprise at least two parallel rows of supports 7 aligned in the direction of movement and will include the guide path in the heating device 10, as well as its inlet 24 and its outlet 25. The movement of the carriers 8 in the first and second parts 21, 22 of the guide path is obtained by pressing on elements of jacks, shown schematically at 27 and 28. Because of this, this guide track 20 constitutes a closed circuit, the linear speed of displacement it is about six times larger in the first part 21 relative to the second part 22. This allows the gradual and optimum warming of the preforms over a prolonged period of time. When the warming phase of the preforms requires a longer time than the other phases and production operations, a continuous operation with very high production is obtained, while the length of the production trajectory is reduced and thus the overall size of the machine. Referring to Figure 2, the stretch-blow device 12 comprises two molding members 30, 31, each including three mold cavities 32. As the molding members are driven simultaneously, six molded receptacles are obtained per molding cycle . Such a cycle is typically of a duration of three seconds, which allows a production of 7200 receptacles per hour, while obtaining a heating of a sufficient duration in the heating device 10. The construction of this heating device 10 is explained in more detail with reference to Figures 3 to 6 and comprises an oven 4 with a movable frame 43 mounted vertically and slidably on the frame 1. Thanks to the pneumatic jacks 41, this furnace 40 can then rise from an active position (Figure 4B and 5) to an inactive position (Figure 4A) during an interruption in production or during stopping or starting the machine. Thus, the large number of preforms in the oven is not damaged. In this way, even when the oven is closed during an interruption, there are risks that the remaining heat will severely damage the preforms placed in the oven. With a mobile oven, this problem is completely overcome. Furnace 40 comprises three heating bodies 42 suspended from movable frame 43. Each heater body comprises six bidirectional carbon sheet heating tubes, 44, which extend longitudinally over the larger portion of the furnace. These tubes 44 are arranged so as to emit radiation heat directed to the two opposite sides. The heating bodies 42 are in active position disposed between two rows of preforms, in order to simultaneously heat the preforms 2 of the two rows. Each heating body 42 and the two rows of preforms associated therewith, are supported by a heating cap 46, secured to the frame 43 and provided with insulating plates 47 of a refractory material, such as alumina. On the furnace, the supports 7 for the preforms are protected by a protective profile 48. The fans 49 (FIG. ), arranged at the entrance and exit of the oven 40, ensure the circulation of the air in the heating zone. With reference to Figure 6, the preforms 2 are arranged, neck down, in the upper portion of the support 7, constituted by an annular retaining member 60. The supports 7 comprise a tubular portion 61 which passes through bearings 52, coupled in the holes 17 of the plates 16. These bearings 52 are also retained by means of an annular groove 53 in the rails of the guide track 20 on the which plates 16 are supported. The supports 7 are, at their lower end, secured to a drive pinion 55. The second part 22 of the guide track 20 is provided with three rotary drive mechanisms 56 for the preforms 2. These mechanisms 56 each comprise a double chain or pulley 57, arranged parallel to the guide track, between two pinions and driven by a motor 58. This motor drives a pinion 59 that engages with the lower portion of the double chain 57, while the upper portion of the double chain 57 acts in conjunction with the pinions 55 of the supports 7 to drive the latter in rotation . Thus, the preforms 2, arranged on the two sides of the heating body 40 are continuously rotated during their passage through the heating device 10. The guide track thus comprises three pulse mechanisms 56, arranged between two adjacent rows of supports 7. The Figure 3A shows a conventional heater body 42a, comprising a number of tungsten lamps or tubes 42a, which allow heat radiation to be directed only on one of its sides. It is therefore necessary to supply a heating body provided with an insulator plate 47a for each row of the preforms. The heating body 42 (Figure 3B), according to the present invention, is provided with bidirectional carbon-sheet heating tubes 44, which allow more regular radiation to be emitted, distributed on two opposite sides of the heater body 42. Therefore, , a single heating body allows simultaneously processing two rows of rotating preforms 2. The heating body 42, according to the present invention (Figure 3B), which uses carbon tubes, each with a power of 2 kW, allows substantial savings of energy, while obtaining a more regular heating in relation to the conventional heating bodies (Figure 3A) that use 2 x 4 tungsten tubes with a power of 4.2 kW each. The combination of the heating device 10 with a bidirectional heating body 42 and of the guide track 20, comprising a part 22 with a plurality of parallel rows of preforms associated with the heating device 10 and a part 21 having only one row of preforms for the other production phases, it allows obtaining an excellent synchronization of the different phases and operations carried out along the guide track 20 of the machine, while considerably reducing the overall size of the latter. This machine is particularly well suited for the production of polyethylene terephthalate receptacles. According to a modification, it will be possible to supply carriers comprising another number of carriers 7 different from two, this number can be, for example, between one and six.

According to other modifications, it will be possible to supply a guide track 20 comprising, even in its first part 21, in the stretching-spreading device, two or more rows of preforms parallel to the direction of movement. The guide track will then be comprised in the second part 22 in the heating device a number of parallel rows of preforms 2 at least twice as large as the number of parallel rows of preforms in the first part 21. Thus, the speed of movement of the preforms in the heater device 10 will be at least twice as low as the velocity in the stretching-socking device. The guide track 20 will comprise, in its second part 22, according to its uses, a number of parallel rows of preforms comprised between two and twelve and preferably six, as illustrated in Figure 2. If the stretch-blow device 12 comprises at least one row of n mold cavities 32, aligned parallel to the direction of movement, the guide track 20 will preferably comprise, in its second part 22, n rows of parallel preforms 2. Thus, the non-preforms arriving at the end of the second part 22 of the guide track 20, can be introduced together in a transport cycle in the stretch-spreading device 12, which can be constituted by any blow molding device, with or without a stretching rod. In the modality of Figure 2, n is equal to six, but this number can, in modified modalities, be equal to a number between two and twelve. It will be noted that the direction of movement of the preforms 2 in the second part 22 of the guide track 20 is substantially perpendicular to the direction of movement of the preforms 2 in the first part 21 of this guide track in the stretching device. blown and charging device 5. Thus, the first part 21 of the guide track 20 preferably has the general configuration of a U, whose legs are connected in a straight line by the second part 22 of the guide track 20. This The latter serves as a kind of storage with a low movement speed of the preforms, which allow the gradual and regular heating of these preforms. Of course, the embodiment and modifications described above are not limiting in any way and they may be subject to any desired modification within the scope defined by claim 1. In particular, the movement of the carriers 8 can be effected by any other element actuator, such as pulleys or impulse chains, graduated wheels acting in conjunction with the supports 7 or with the carriers 8. The guide track 20 can, particularly in its first part 21, have just another shape, for example a semicircle or an irregular configuration. The machine can be connected directly or indirectly to other devices that perform a further treatment of the receptacles, they can also be preceded by an installation for the production of preforms.

Claims (18)

1. CLAIMS 1. Machine for the production of receptacles of plastic material, which comprises a frame and is arranged along a guide track, at least one heating device and a blow molding device, these receptacles are formed from of preforms, arranged on carriers, which move along the guide track, characterized in that the guide track comprises, in the heating device, a number of rows of preforms, parallel to the direction of movement, at least twice as large as the number of parallel rows of the preforms, in the blow molding device.
2. 2. Machine, according to claim 1, characterized in that the guide track comprises, in the blow molding device, a single row of preforms, aligned in the direction of movement, while comprising, in the heating device, a number of parallel rows of preforms, which is between two and twelve, preferably is six.
3. 3. Machine, according to claims 1 or 2, characterized in that the blow molding device comprises at least one row of n mold cavities, aligned parallel to the direction of movement, the guide track comprises, in the device of heating, n rows of preforms parallel to the direction of movement.
4. 4. Machine, according to claim 3, characterized in that n is between two and twelve, preferably is six.
5. 5. Machine, according to claims 1 to 4, characterized in that the direction of movement of the preforms on the guide track, in the heating device, is substantially perpendicular to the direction of movement of the preforms, in the device blow molding.
6. 6. Machine, according to claim 5, characterized in that the guide track comprises a part of configuration generally in U and a second part, which connects in a straight line the legs of the U.
7. 7. Machine, according to claim 6, characterized in that the first part comprises the blow molding device, a discharge device for the produced receptacles and a loading device for the preforms, the second part comprises the heating device.
8. 8. Machine, according to one of claims 7, characterized in that each carrier comprises a plate, slidably mounted on the guide track, each plate carries two supports, which are each adapted to receive a preform .
9. 9. Machine, according to claim 8, characterized in that the carriers are of a generally rectangular configuration and comprise, aligned along their greater length, two bearings, in which the supports are mounted and rotatably retained.
10. Machine, according to claim 9, characterized in that the supports are constituted by tubular members, comprising, at their upper end, an annular retaining element, in which the preforms are retained by their necks, these tubular members pass through the bearings and are provided, at their lower end, with a pinion, adapted to act in conjunction with a pulse device, disposed in the heating device, to drive in rotation the support and the preforms, the The guide track comprises rails, on which the supports rest, these bearings comprise grooves, adapted to act in conjunction with the rails, so as to be retained in the guide track.
11. 11. Machine, according to claim 8, characterized in that the carriers are arranged on the guide track, so that the two supports of each carrier are aligned in the direction of movement in the blow molding device and so that the two supports of each carrier are aligned in a direction perpendicular to the direction of movement in the heating device.
12. Machine, according to claim 8, characterized in that it comprises, in the heating device, between one and six, preferably three rows of carriers, these rows are aligned side by side in the direction of movement.
13. 13. Machine, according to one of the preceding claims, characterized in that the heating device comprises at least one heating element of elongated configuration, arranged between two parallel rows of preforms and adapted to emit heat of radiation on two opposite sides, in the direction of the two rows of preforms.
14. 14. Machine, according to claim 13, characterized in that each heating body comprises a plurality of bidirectional carbon sheet heating tubes, which are superimposed.
15. 15. Machine, according to claims 12 and 13, characterized in that the heating device comprises a number of heating bodies, comprised between one and six, preferably three, these heating bodies are arranged parallel to each other, each body of heating is disposed substantially in the middle of two preforms, carried by each carrier.
16. 16. Machine, according to claim 15, characterized in that each heating body and the two adjacent rows of preforms are surrounded by a cap.
17. Machine, according to one of claims 13 and 14, characterized in that the heating element (s) are movably mounted in relation to the frame of the machine, to be moved from an active position, in which they are arranged substantially in front of the preforms, to an inactive position, in which they are spaced from the preforms.
18. 18. Machine, according to claims 16 and 17, characterized in that the heating bodies, surrounded by their caps, are mounted on a moving frame, the latter is adapted to be moved vertically under the action of a lifting device .