MXPA01008483A - Conduit-making apparatus with a variable-diameter winding drum - Google Patents

Abstract

An apparatus is disclosed for making a conduit or pipe. An extruder (12) is provided for producing a strip (14) of continuous thermoplastic. A winding drum (10) receives the strip and helically winds the strip around the drum's perimeter to form a conduit having an inner diameter corresponding to the outer diameter of the drum. The drum (10) includes a core tube (36) surrounded by a plurality of rollers (20) which define the outer diameter of the drum. The rollers (20) rotate to advance the strip around the drum. A plurality of support columns (24) are used to support the roller (20) at each end. A hub assembly (16) is used to movably support the support columns in slidable engagement. The support columns (24) are radially displaced by the hub assembly between two positions, in order to vary the outer diameter of the drum (10) between two diameters.

Description

APPARATUS FOR DEVELOPING A DUCT WITH A VARIABLE DIAMETER WIND DRUM.

FIELD OF THE INVENTION The present invention > n is directed to the field of apparatuses for the formation of ducts, tubes, pipes of large diameter or the like, generally of cylindrical form, from an extruded thermoplastic strip. The North American Patent No.

No. 4,033,808 to Petzetakis, describes an apparatus for making a large diameter tube from thermoplastic resin, the description of which is incorporated herein by reference. A hollow profile strip of synthetic resin is extruded and wound helically around a winding drum to make a continuous pipe The adjacent turns of the propeller are thermally fused together with the axial pressure that is being applied on the strip, so that a test-proof tube is made, which can be used for a number of applications, particularly for underground use, for example, as a sewage or sewage pipe, storm sewer or any other liquid transport.

The above apparatus includes a drum for forming the duct around it, and the drum includes a central tube surrounded by a plurality of rollers to which the extruded thermoplastic strip is rolled, as these revolve around the drum. The drum of the previous apparatus has a fixed diameter, so that only one diameter of the tube can be produced with each apparatus. Since a normal manufacturer of pipes, manufactures conduits or pipes of different diameters, it would be necessary to buy and maintain several of the same devices, which includes a considerable investment and ongoing expenses.

Background of the Invention In a conventional process for making conduits, the "residence time" is the period within which the plastic remains in the drum during the manufacturing process. Since the manufacturing range is limited to L residence time, it would be desirable to shorten this interval by increasing the drum speed. Typical manufacturing ranges can range from 136.2 to 1,589 krg / h depending on the size of the tube. Normally, the large diameter pipe or conduit is manufactured at approximately 454-90 krg / h. However, since the range is increased, the duct may not be completely cooled when it comes out of the drum. This causes the duct to contract slightly inward, undesirably decreasing the final diameter of the duct by a small but significant amount.

SUMMARY OF THE INVENTION By virtue of the aforementioned inconveniences with the foregoing apparatuses, there is therefore a need for a tube or conduit that retains the advantages of the previous apparatus while a large diameter tube or conduit is manufactured. more than one diameter. There is also a need for an apparatus that has a drum that allows variations in accuracy in the diameter of the tute / duct, to allow the decrease of the residence time, thus increasing the manufacturing range. These and other needs are met through the present invention, in which an apparatus for making a conduit is described. An extruder is provided to produce a continuous thermoplastic strip or tape. A winding drum receives the strip from the extruder diel in a state substantially melted flexible, fusible, and wound in illoidal form the strip around the perimeter of the drum to form a conduit having an internal diameter corresponding to the outer diameter of the drum. The drum includes a center tube surrounded by a plurality of rollers defining the outer diameter of the drum. The rollers rotate to advance the strip around the drum. A plurality of support columns are used to support the rollers erm. each end. A die assembly is used to movably support the support columns in a slidable assembly. The support columns are displaced radially along the die assembly between two positions, in order to vary the outer diameter of the drum between the two diameters. As will be appreciated, the present invention has the ability to develop other and different modalities, and its various details have the ability to modify in several aspects, all without departing of the present invention. Therefore, the drawings and the description should be considered illustrative and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present invention will be described below only by way of example, with reference to the accompanying Figures wherein the elements contain similar reference numbers, and wherein: Figure 1 is a view of side section illustrating the winding drum and related components according to the present invention. Figure 2 is a top view in detail of the head of the extruder of the present invention and the related components. front section illustrating the winding drum and related components according to the present invention Figures 4A and 4B are respective side section and partial oblique views illustrating an alternative die assembly according to the present invention.

Detailed Description of the Invention The Figures are intended to illustrate the preferred embodiment of the present invention, and not to limit it. The present invention is directed to an apparatus for making a tube or conduit having a variable diameter winding drum, generally indicated by reference number 10. An extruder 12 is provided for extruding a continuous thermoplastic strip or ribbon 14 of said material, such as is suitable for the manufacture of ducts or tubes including but not It is limited to: PVC, polyethylene or any other type of plastic material. The winding drum 10 receives the thermoplastic strip in a substantially fused, flexible and meltable state, j rotates as will be described in greater detail below to helically wind the strip around the perimeter of the drum. The duct thus formed has an inner diameter corresponding to the outer diameter of the drum 10. The drum 10 includes a central tube 36 surrounded by a plurality of rollers 20. The outer diameter of the drum 10 is defined by the plurality of rollers 20. , the parts rotate in axial form as the strip advances around the drum 10. The plastic covering the tube is extruded in a rectangular belt configuration, called a "profile". The shape of the profile, since it is wrapped on the rollers of the drum, is preferably formed by a degree 50 having rods of calibration 52, and are adhered to the extruder 12, as shown in Figure 2. The position of the profile is preferably adjusted by a guide plate 54, which propels the profile to make contact with the joint wrapping, as shown in Figure 2. Of course, it should be appreciated that any other means can be used to form and position the profile, without departing from this. invention The rollers are mounted and slightly oriented along 1 drum to create a helix angle as the profile is wound around the diameter of the drum, this also being wound longitudinally along the axis of the drum 22, following the angle propeller. The calibration rods 52 and the guide plates 54 are aligned so that the vertical profile coming from the extruder is edge to edge with the plastic that is wrapped in the previous turns of the drum.

Since the plastic au is slightly fused, the two sections are fused together to form a weld. The outer diameter of the drum 10 is varied in the present invention, by means of a die assembly 16 and associated components that vary the radial distance of the rolls 2¡0 from the drum axis 22. Each roller 20 is supported by a pair of support crowns 24 which retain the axial supports 34 on each end of the roller. The die assembly 16 movably supports the support columns 24 in an assembly. I slid it. The die assembly includes a pair of dies 26, which are preferably engaged in a threaded manner with a die connecting tube 28., so that both dies 26 are moved in tandem. In the preferred embodiment, a reciprocal distribution is used, for example, an end plate provided by 8 threaded screws, to adjust the die assembly 16 parallel to the drum axis. 22, thereby noting the column of the support 24 in or out for any increase or decrease in the outer diameter of the drum 10. The 8 threaded screws are evenly distributed through the end plate 64 at the end of the screw. discharge of the drum 10 from both the thrust screws 60 and the extraction screws 62. The thrust screws 60 and the extraction screws 62 are alternately spaced apart from the end plate 64, uniformly.

The thrust screws 60 are used to adjust the die assembly parallel to the drum axis 22 to the loading end of the drum.

. In order to fit the movement of the die assembly 16, the thrust screws 60 are screwed inwardly and the extraction screws 62 are clamped with each turn of the thrust screw. This movement increases the outer diameter of the drum 10. The extraction screws 62 are used to adjust the die assembly 16 parallel to the drum axis 22 and to the discharge end of the drum 10. The extraction screws 62 are threadedly engaged in the die 26 at the discharge end of the drum 10. In order to fit the movement of the die assembly 16, the extraction screws 62 are screwed and the push screws 60 are loosened with each turn of the extraction screws 62. This movement decreases the external diameter of the drum. Alternatively, the reciprocal distribution may include one or more spring-biased rotors to vary in ective form and maintain the graduation position of the die switch 16. use any similar reciprocal distribution, without departing from the present invention Each die 26, has a substantially frusto-conical tapered surface 30. The dies 26 are mounted coaxially with the drum 10 (eg, the frusto-conical shaft is collinear with the axis of the drum 22). The support columns 24 fit with the tapered surface 3C of the respective dies 26, so that at the moment of the displacement of the support columns 24,? along the tapered surfaces 30, the support columns 24 and the rollers 20 therein supported, vary in their radial distance from the axis of the drum 22. In the preffered mode, the support columns 24 are held in place by the guides of the respective support column 32, which allow the radial displacement of the support columns 24, but prevent axial displacement along the longitudinal axis 22 of the drum. At the moment of axial displacement of the die assembly 16 between the end positions Pl and P2, the support columns 24 slide up and down on the used surface 30, thereby varying the radial position perpendicular to the drum axis. 22 of the rollers between the maximum positions Rl and R2, the which respectively correspond to the maximum and minimum outer diameters of the drum. In the preferred embodiment, the diameter of the drum can be between 0.5334 m and 1524 m. However, it should be appreciated that the larger and smaller diameter drums can be made without departing from the present invention. In order to ensure engagement of the dies 26, each support column 26 preferably terminates in a T40-shaped portion, which is received within a respective T42-shaped groove formed in the tapered surface 30 of the die 26. At the time of displacement of the die assembly 16, the support columns 24 are retained in a slidable manner by the engagement of the respective T40-shaped portions with the respective T42-shaped slots. In an alternative embodiment for the assembly of the dies 26, as shown in Figures 4A and 4B, each support column 24 may be connected to a linear support 70 adhered to a rail 72, fixed to the tapered surface 30 of the die. 26. At the time of displacement of the die assembly 16, the support columns 24 are slidably retained by the linear support 70 on the rail 72.

Of course, it should be appreciated that other displacement schemes could be contemplated without departing from the present invention. The present invention, as described, can provide a variable drum diameter between at least two standard conduit sizes, thereby saving the expense of acquisition and maintenance of multiple apparatuses. The present invention can also be used to achieve minute adjustments to the diameter of the drum, and to the corresponding diameter of the last duct product. In this way, the residence time can be shortened, since the light • resulting decrease in the diameter of the duct increasing the manufacturing speed, can be compensated by a corresponding increment in the diameter of the drum. Using the above apparatus, the plastic is extruded optimally in a range of about 454 kg /, for the most common tube sizes With the present invention, this range can be increased to between 681-908kg / h, or even higher, with an increase in corresponding manufacturing range of between 50 and 100% or more. As described above, the present invention solves many of the associated problems with the previous systems, and presents an efficiency improved and reduced expenses. However, it will be appreciated that those skilled in the art can make various changes in the details, materials and distributions of the parts herein described and illustrated for the purpose of explaining the nature of the present invention, within the 3 principles and scope thereof, as expressed in the appended claims

Claims (5)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as property: CLAIMS 1. An apparatus for making a duct comprising: an extruder (12) for producing a continuous strip 14) of thermoplastic; A winding drum (10) for receiving and helically winding the extruded strip 14) of thermoplastic around the perimeter of said drum; a plurality of rollers (20) in a circular formation centered on the axis of the drum, and defining the outer diameter of said drum (10), each of said rollers having a first end and a second end; u first group of radial support columns (24) that engage said rollers at said first ends and extend from said first ends towards said axis; a second group of radial support columns (24) engaging said rollers at said second ends and extending from said second ends towards said axis; a first and second tapered bases (26) supported to move along said axes, characterized in that said bases move relative to one another in a simultaneous and equal manner in the same direction along said axis, said first tapered base fitting with said first radial support column (24 and said second tapered base). fitting in said second group of radial support columns (24) to impart radial movement respectively to said first and second groups of radial support columns at the moment of axial movement of said tapered bases, and a graduation mechanism (60, 62, 64 which operates to move said tapered bases relative to one another in a simultaneous and equal manner in the same direction along said axis, to impart said radial movement respectively to said first and second groups of radial support columns (24), to vary in this way the outer diameter of said drum (10) 2. An apparatus according to claim 1, further comprising a first group of structure guide (32) interposed radially between said first tapered tee (26) and said first ends of said rollers (20) and configured to block the circumferential movement while allowing radial movement of said first group of support columns radial, to guide in this way said radial movement; and a second group of guide structures (32) interposed in raidial form between said tapered second base and said second > s ends of said rollers (20), and configured to block the circumferential movement while allowing radial movement of said second group of radial support columns, to thereby guide said radial movement. 3. A compliant apparatus with claim 1, wherein each support column (24) includes a T-shaped portion (40) which cooperates with a respective plurality of T-shaped slots (42). which are formed within the outer surfaces (30) of the tapered bases (26), for slidably retaining the support columns (24) 4. A compliant apparatus with claim 1, wherein each support column (24) cooperates with a respective linear support rail system (70, 72) adhered to the outer surfaces (30) of the tapered bases (26), to hold the support columns 24 in a sliding manner. 5. An apparatus according to claim 1, wherein the graduation mechanism comprises a configuration of thrust messes (60) and extraction screws (62), mounted on an end plate (64) to grind said tapered bases.