RU2081067C1 - Apparatus for molding and tempering glass sheets - Google Patents

Abstract

FIELD: glasswork. SUBSTANCE: apparatus for manufacturing irregular-shape glass sheets to be applied in vehicles comprising heating position formed by horizontal furnace; molding position located immediately behind heating position and provided with lower molding ring and upper mold to molding operation; and temper position provided with a group of nozzles to effect fast cooling of glass sheets after molding and with means to displace and fasten glass sheets is distinguished with that indicated facilities contain, following the direction of glass sheets' displacement, cylindrical rollers to displace and fasten sheets inside the furnace, bottom air cushion to support sheets in molding position, and hollow ring to move sheets in molding position, which consists in vertical displacement of sheets towards upper mold and horizontal displacement of sheets in direction of temper position. EFFECT: facilitated sheet making process. 10 cl, 4 dwg

Description

 The invention relates to a device and method for forming and tempering glass sheets having a complex shape for use as windows in automobiles.

 The shape of the car body is of great importance not only from an aesthetic point of view, but also from the point of view of aerodynamics. In this regard, it is also necessary that the surfaces have no discontinuities that will impair the coefficient of penetration of air during the movement of the vehicle.

 For this reason, glass, in particular glass for automobiles, is given a complex shape that can only be obtained in special installations designed for this purpose.

 Known industrial installations for forming and tempering glass sheets of complex shapes for use in automobiles.

A known installation in which the glass transmitted by the rollers is heated in a horizontal furnace, then transferred again by the rollers to the molding position. In this case, the lower, vertically movable form, the flat surface of which is grooved for passing through the rollers transporting the glass, raises the glass from the rollers and transfers it up until the glass is close enough to attract it to the upper form by means of vacuum suction. After molding is completed, the upper mold allows the glass to fall onto an annular element called a shuttle moving horizontally, which transports the glass to the tempering and cooling position [1]
The disadvantage of this installation is mainly that the glass having a high temperature experiences surface deformation as a result of prolonged contact first with the rollers in the molding area, and then with the flat surface of the mold. Surface deformation causes significant optical defects, which is unacceptable for glass used in automobiles.

A known method and device for forming glass sheets having a complex shape. The glass sheets move along the gaseous cushion of the hearth through a horizontal heating furnace, are pulled by transverse rods separated by this space, and reach the molding position, where under, formed by the gaseous cushion, receives glass and transfers it during horizontal movement, and since it has a corresponding bend down , then the glass bends to the desired shape under the action of gravity. The gaseous layer of the hearth is surrounded by a hollow forming ring of the desired configuration, which is located under the layer. When the entire surface of the glass lies on the gaseous cushion of the hearth, the ring lifts it vertically in the direction of the mold to which the glass is attracted by vacuum suction, then the mold lowers the glass onto another ring of the cart with reciprocating movement, which transfers it to the position of tempering and cooling 2]
This installation has several drawbacks: firstly, for the manufacture of each profile, it is necessary to replace not only the lower ring and the upper mold, but also the gaseous hearth pad, which has a curvature similar to the curvature of the finished product, and the gaseous hearth pillow must also be replaced depending on the change dimensions of the surface of the product, since it must be placed inside the hollow forming ring. In addition, the transfer from the furnace to the molding position is carried out by intermediate rollers, which at a given high temperature of the glass can easily cause surface deformation and consequently optical defects.

 In European application N 415826, an installation is described which attempted to eliminate the disadvantages associated with the presence of rollers in a bending position by replacing the rollers with a tape made of a suitable heat-resistant material, which is placed between the lower forming ring and the upper vacuum mold.

 However, this solution also has certain drawbacks, mainly related to the difficulties of controlling such a complex molding system, and also due to the fact that the long residence time of glass heated to a softening temperature on the support tape can cause undesirable optical distortions.

 The aim of the invention is to provide a device capable of eliminating the aforementioned disadvantages and producing at highly competitive production costs.

 The objectives of the invention are achieved thanks to a device containing a horizontal heating furnace, in which glass is passed along the rollers along its entire length, a molding position maintained at the same temperature as in the furnace and equipped with an air cushion of a hearth for supporting the glass, and a lower molding ring, which participating in the process of forming glass together with the upper mold, it also transfers the glass horizontally to the nozzles for tempering, thus acting as a shuttle.

 The use of a roller conveyor in the furnace can significantly accelerate the heating of glass and reduce production costs compared with the case when the air cushion hearth is located along the entire length of the furnace. In the latter case, the transverse rods, which pull the glass along, can leave prints on the glass, so this can lead to an increase in marriage.

 At the molding position, the rollers transmitting and supporting the glass are replaced by an air cushion, this cushion is obtained by blowing hot air through a plurality of nozzles arranged in such a way as to provide uniform support to the glass sheet and to allow the shuttle ring to cross the glass flotation level and be placed under the glass.

 The term "hot air" means both heated air and a mixture of air and exhaust gases generated, for example, during the combustion of methane.

 The height of the nozzles is such that it allows the forming ring, which often has a large radius, to fall below the level of flotation, and the shape, number and location of the nozzles are such that uniform glass support is provided, with the exception of, respectively, the zone in which there are no nozzles necessary to pass the forming ring, this zone can be easily obtained by removing nozzles from it and closing the corresponding holes with threaded plugs, and the nozzles have cylindrical threaded rods, therefore, they can be screwed into the holes oppressive chamber.

 According to a specific embodiment of the invention, the internal geometry of the nozzle, allowing air to pass so as to provide adequate support for the glass sheet, is formed by a converging channel to reduce the pressure drop created at the inlet, a cylindrical part with a calibrated cross section to achieve a substantially constant flow rate through each a nozzle with a long channel with a larger diameter than the previous cylindrical part, and it is preferably diverging to slow down along eye fluid, with the final part configuration in the form of a truncated cone to provide final slowing of the fluid and consequently to obtain a flat pressure profile at the outlet section of the nozzle.

 The cylindrical portion with a calibrated cross section has a diameter of preferably 2 to 8 mm.

 The diameter of the nozzle exit section is preferably between 40 and 100 mm.

The pressure of the air supply to the nozzles is preferably 50 to 100 mlbar, and this pressure can be adjusted during the operating cycle to values between the upper and lower limits to change the distance between the glass sheet and the level of the nozzles and / or to optimize the use of hot air, which has the temperature is preferably 600,700 ^o C.

 The distance of the glass sheet from the level of the nozzles is preferably 0.2 1 mm, and it can vary during the duty cycle, fluctuating between the indicated limit values depending on the air pressure supplied to the nozzles.

 The nozzles are located on the discharge chamber with their perpendicular axes located on the vertices of a triangle or square or grid rectangle in such a way that in any case there is adequate space for air to escape between adjacent nozzles for better support of the glass sheet, especially if the nozzles have a large diameter outlet section .

 It may be necessary to use nozzles of a smaller diameter near the areas where the forming ring passes, so that nozzles with an outlet section of different diameters are simultaneously on the same plane without creating any interference with the glass sheet.

 The lower mold is formed by a hollow ring that does not have gaps in its profile, which is supported by a metal element that carries a shape that allows the ring to first carry out a vertical movement from a plane below the hearth air cushion to the upper mold and then make a second horizontal movement to transfer the ring from a position molding on a vacation position.

 The aim of the invention is to provide a device for forming and tempering glass sheets having a complex shape for use as automobile glasses, the device comprising a heating position formed by a horizontal furnace, a molding position immediately following the heating furnace and provided with a lower forming ring and an upper shape for forming, a tempering position equipped with nozzles for quickly cooling the glass sheets after molding, and means for transferring and supporting the glass sheet, moreover, the device is characterized in that the said means include following, according to the direction of movement of the glass sheets, cylindrical rollers for transporting the sheets inside the heating furnace, an air cushion on the hearth for supporting the sheets at the forming position and a hollow ring for transporting the sheets to the forming position for forming and moving sheets horizontally for transfer to a vacation position.

 The aim of the invention is to provide a method for molding and tempering glass sheets having a complex shape for use as windshields for automobiles, comprising a step for heating a glass sheet, a molding step and a tempering step, the method being characterized in that during the heating step, the glass the sheet moves along a series of cylindrical rollers, and during the forming stage it moves first along the air cushion of the hearth and then on the forming ring, which also transfers it horizontally to the bending position a.

 The advantages achieved in accordance with the invention are as follows: glass can remain on a cushion of hot air for a sufficiently long time without significant deformation testing and therefore optical defects are limited, since an air flow is generated so that heat is transferred and therefore no local deformations on the surface of the glass; the air cushion is flat and therefore it can be used regardless of the shape of the bent glass sheet, thus, in comparison with known methods, the cost of replacing equipment is reduced; apply the same plane on which the nozzles are fixed, regardless of the geometric shape of the manufactured product; the forming ring can cross the flotation level of the glass sheet and for this reason the gaps on the ring itself, which are necessary when the rollers are present, are not required.

In FIG. 1 shows a general view of a device in accordance with the invention and a vertical sectional view of a molding position; in FIG. 2 is a vertical sectional view of the vacation position; in FIG. 3 is a top view of the plane of the glass support and stops; in FIG. 4 is a vertical sectional view of a device for forming an air cushion;
The device in accordance with the invention comprises a heating furnace 1, a molding position 2, a tempering position 3, and a feeding position (not shown).

 In accordance with the invention, in the heating furnace 1, the glass is heated to a softening temperature during its transfer along a horizontal path formed by a series of 4 cylindrical rollers, the movement of which is provided by a working mechanism (not shown).

The molding position 2 follows immediately after the horizontal furnace 1. The molding position is located inside the hot chamber 12, the walls of which are made of refractory material and which is maintained at a temperature of about 650 ^{° C.} by means of electric heating elements (not shown).

 The molding operation control devices are located outside the chamber 12, while the molding equipment is installed inside the chamber.

 Immediately after exiting the furnace 1, inside the hot chamber 12 there is an injection chamber 5, into which hot air is supplied through a pipe 6 and which carries a plurality of nozzles 7 of an appropriate size and quantity.

 The group of nozzles 7 forms a support air cushion, which is an extension of the glass conveyor equipped with rollers 4. This air cushion also has a flat surface.

The supporting frame 8 supports the discharge chamber 5 inside the hot chamber 12. The frame 8 has two hinges 9 near the outlet of the furnace 1, and on its opposite side there are two mechanical lifting devices 10, moved by the engine 11, which can tilt the surface of the discharge chamber by 1 2 ^o relative to the horizontal.

 When the glass sheet V is located on an air cushion, the discharge chamber 5 is tilted down, thereby sliding the glass and providing a suitable adhesion of the glass edge to the control stops 45.

 The injection chamber 5, preferably made of stainless steel, has a plurality of threaded holes 52 on its upper plate 51 so that it is not detrimental to the plate, while at the same time allowing the nozzles to be optimally positioned in accordance with the geometric shape of the formed glass sheet.

The nozzles 7 have a first cylindrical threaded part 53 so that they can be screwed into the plate 51 of the pressure chamber 5, the second cylindrical part 54 and the third part 55 in the form of a truncated cone, and they are preferably made of stainless steel, provided that the temperature is hot the chamber at the molding position is between 600 and 700 ^o C.

 In accordance with a specific embodiment of the invention, the internal geometry of the nozzle, capable of providing an appropriate air flow, is formed by a first converging channel 56, a subsequent cylindrical part 56 with a calibrated cross section, a cylindrical channel 58 with a larger diameter than the previous channel 58, and an end part 60 in the form of a truncated cone to ensure the final slowdown of fluid flow.

 The cylindrical portion 57 preferably has a diameter of 2-8 mm.

 The diameter of the outlet section of the nozzle 7 is preferably 40 to 100 mm.

 The nozzles 7 are located on the discharge chamber 5 at the vertices of the square grid in such a way that the required space is formed for air injection.

 In areas left without nozzles, so that the forming ring 24 can pass, the openings 52 are closed by threaded plugs 61.

 Holes are formed on the side walls of the hot chamber, which are necessary for repair and inspection. In addition, the hole 13 allows the glass to enter the chamber, and another hole 14 to exit from it.

 To eliminate heat loss, an opening 14 is provided with a hinged shutter 15, which opens during the cycle, allowing the shuttle 16 to enter and exit.

 The upper molding mold 17 is formed by a burned-out mold 18 having a perforated plane to achieve a vacuum effect for sucking glass V, the vacuum being created by a Venturi system (not shown) that pushes air sucked in through the tube 25.

 The mold 17 is attached to two support rods 19, which exit the hot chamber 12 through channels 20 formed in the material of the lining of the arch and which are connected to the movable frame 21, which is moved vertically in turn by means of a working mechanism 23 and a numerically controlled engine 22.

 Vertical movement of the upper mold provides centering of the mold in accordance with the forming ring 24.

 The working mechanism, consisting of chains 26 and engine-driven winch 27, provides lifting of the movable part of the mold to simplify its removal during equipment replacement.

 The shuttle 16 supports the hollow forming ring 21 and moves vertically inside the hot chamber 12 and is reciprocating in the horizontal direction to transfer the ring 24 from the hot chamber to the vacation position 3.

 The supporting structure 29 carries lead screws 30 to which longitudinal guides 28 are attached, having a section in the shape of an inverted V.

 The wheels mesh with the V-guides and carry the shuttle 16, which is made of two independent side sections held in parallel by engagement of the spindles 30.

 A vertically movable frame 32 is connected to the wheel 33, which is designed to engage in the lift 34, while the system 35, directed by a rail, with a parallel bar prevents the oscillation in lowering time.

 The elevator 34 is a device that allows the element 16, the bearing form, to carry out vertical movement. The wheel 33 lies on the link 34 of the lift, and the engine 37 moves the lift vertically by means of the rack 36.

 The horizontal reciprocating movement of the shuttle 16, bearing the shape, is provided by the lead screws 30, engaged with the roller wheels 38, connected to the side sections of the shuttle itself and elastically pressed on the thread of the lead screws 30. Two lead screws are used, one on each side of the machine, however, they rotate in the opposite direction and have right and left threads, respectively.

 Lead screws 30 are held by their ends on self-aligning roller bearings (not shown) and are driven by a gear belt drive 39.

 The stop group 50 receives the glass V when it leaves the furnace, thereby gradually slowing down the movement of the glass while it is on the air cushion formed by the nozzles 7.

 Two support structures 41, one on each side of the machine, articulated at position 42, hold the carts 43, which are moved by a numerically controlled motor (not shown).

The stop rods 44 and 48 have ceramic wheels 45 at their ends in contact with the glass V, the rods themselves being slightly flexible so that they can be adapted to the position of the plane 5, which can be inclined by 1 or 2 ^o .

 The glass sheet is heated to the softening temperature in the furnace 1 when it moves along the roller hearth 4, then after it leaves the roller hearth, the sheet is transferred through the hearth air cushion to the first pair of rods 44, which protrude from the bogies 43 and make contact with the leading edge of the glass sheet and slow down its movement until it stops at the appropriate location defined by the forming ring installed under the flotation plane.

 Another pair of rods 48 protruding from the bogies 43 comes into contact with the side edge of the glass sheet and centers it in accordance with the position defined by the forming ring 24, which is in the standby position below the flotation level of the glass 24, which is located under the flotation plane.

 After centering the glass sheet, the ring 24 rises, taking the glass sheet V and transferring it in the direction of the mold 18 until it is at such a distance that the mold can create a vacuum with its perforated plane to attract the glass sheet V, which thus continues to bend taking the required shape.

 After molding is completed, the mold 18 releases the sheet back onto the same ring 34, which quickly moves to the tempering position 3, containing the opposing upper 46 and lower 47 nozzles, which temper the molded glass V, and on which the glass is also unloaded by using a differential pressure between the upper and lower nozzles, which pushes the molded glass up, causing it to disconnect from the ring 24.

 After that, the forming ring 24 returns to the molding position 2, being installed under the air cushion of the hearth in anticipation of the arrival of the next glass sheet for molding.

Claims (10)

 1. A device for forming and tempering glass sheets having a complex shape for use as glasses in automobiles, including a heating position with a horizontal furnace, a molding position located immediately after the heating position and equipped with a movable hollow ring to support the glass sheets at the molding position and fixed the upper mold, a tempering position located after the molding position and equipped with tempering nozzles for quickly cooling the glass sheets after molding, characterized in This comprises a roller conveyor at the heating position for feeding the glass sheet in the processing direction through the furnace along a predetermined path, an air cushion of the hearth at the molding position located after the roller conveyor along the predetermined path to support the sheets transported to the molding position at the level of the melting plane, the upper the mold is located under the air cushion and the swimming level and contains a perforated forming plane and a vacuum means to ensure air intake through a perforated forming plane in order to attract a glass sheet thereto, ring moving means for vertically moving the hollow ring from a position below the swimming level to the perforated forming surface of the upper mold and for horizontally moving the hollow ring from the molding position to the tempering position, and that the air cushion comprises an air discharge chamber and a plurality of upward directed air supply nozzles installed separately with the possibility of dismantling on the air discharge chamber and -rotating with it for feeding air therethrough from vozduhonagnetatelnoy chamber to form an air cushion, wherein vozduhonagnetatelnaya chamber has an annular zone without nozzles corresponding to the shape of a hollow ring placed in the annular zone below the level of navigation.  2. The device according to claim 1, characterized in that the air supply nozzles are mounted in the air discharge chamber by means of threaded cylindrical ends and the nozzles include an upwardly narrowing channel communicating with the discharge chamber to reduce the pressure drop at the inlet, a first cylindrical part extending from the upwardly narrowing channel and having a predetermined cross-section to ensure a constant air flow rate, the second and third cylindrical parts extending from the first cylindrical part and having a second and three rd set sequentially enlarged transverse cross section, and the end portion in the form of a truncated cone extending from the second cylindrical portion for reducing the air flow rate and providing the pressure in the outlet of each nozzle section in order to obtain a flat surface of the air cushion.  3. The device according to paragraphs. 1 and 2, characterized in that the molding position further includes a frame supporting the air discharge chamber, the first end of the frame being mounted on a pair of hinges and the second end on mechanical jacks to tilt the air discharge chamber and air cushion down in the processing direction.  4. The device according to paragraphs. 1 to 3, characterized in that the molding position further includes an abutment means for stopping the glass sheet in a predetermined position on the air cushion above the hollow ring when it is in a predetermined position below the swimming level, wherein the abutment means comprises a pair of control stops, each of which includes a cylinder and a rod that leaves the cylinder until it comes into contact with the leading edge of the glass sheet, and a second pair of control stops, each of which includes a cylinder and a rod that leaves the cylinder pa until until it comes into contact with the side edge of the glass sheet.  5. The device according to paragraphs. 1 to 4, characterized in that each nozzle includes a part having a cross-sectional diameter of from 2 to 8 mm  6. The device according to paragraphs. 1 to 5, characterized in that each nozzle has a channel for discharging air with a cross-sectional diameter of from 40 to 100 mm.  7. The device according to paragraphs. 1 to 6, characterized in that the air cushion includes means for supplying air under pressure from 50 to 1000 mmbar to the air supply nozzles.  8. The device according to paragraphs. 1 to 7, characterized in that the air discharge chamber includes a plurality of fastening means for threaded nozzles for detachably securing the plurality of air supply nozzles and for ensuring communication of the nozzles with the air discharge chamber.  9. The device according to paragraphs. 1 to 8, characterized in that it further comprises means of threaded plugs screwed with the possibility of disassembling with means of fastening of threaded nozzles located in an annular zone to prevent air leakage from the air discharge chamber through means of fastening of threaded nozzles located in an annular zone.  10. The device according to paragraphs. 1 to 9, characterized in that the fastening means of the threaded nozzles respectively comprise openings with an internal thread, each nozzle includes a cylindrical part with an external thread mating with one of said openings, and each means of the screw plug contains a threaded plug with an external thread, mating with one of specified holes.

Images