AU653507B2

AU653507B2 - Supporting frame for a continuous transport device

Info

Publication number: AU653507B2
Application number: AU70595/91A
Authority: AU
Inventors: Jacques Maurice Ernest Wolf
Original assignee: LTG Lufttechnische GmbH
Current assignee: LTG Lufttechnische GmbH
Priority date: 1989-12-18
Filing date: 1990-12-14
Publication date: 1994-10-06
Anticipated expiration: 2010-12-14
Also published as: JPH05503910A; EP0506834A1; EP0506834B1; WO1991008975A3; FR2655959A1; ATE93811T1; AU7059591A; BR9007918A; DE59002588D1; KR100233206B1; CA2071964A1; MX174619B; WO1991008975A2; FR2655959B1; ES2044721T3; RU2093448C1

Abstract

A support, in particular a profile or wire frame, for a continuous transport device for transporting thin, flexible objects, panels or metal sheets, through a drying tunnel or through a tunnel for heat treatment or the like is characterized by the shape of its surface, which receives the objects to be transported. The purpose of this shape is to bend the panels to be transported forward when receiving them approximately horizontally in order to prevent them from bending vertically under their own weight as soon as they are lifted approximately vertically from the wire frame before or during transport. In the case of this latter deformation, contact points are produced between the panel and the preceding wire frame, which seriously impair the quality of the dried products.

Description

Description This invention concerns holding fixtures which are known as wire frames and are mounted parallel behind each other on one or more chains (or similar devices). In this manner a continuous transport of the sheets or plates is ensured, so that they are passed through a tunnel to be dried or heat treated or they can be merely in a holding position on the same production line between two subsequent processes.

Transport systems of this type are well known and are often used. Fig.1 illustrates a typical example used in the metal packaging industry. In the metal packaging industry thin iron sheets or aluminium plates are printed or coated for the puroose of protection or appearance. For this it is necessary to dry or polymerise the metal sheets between 1200'C and 220°C for about ten minutes, so that the ink or the like would adhere firmly to the metal, thus satisfying the protective or decorative function. This application is an example only, as the wire frames of this invention may carry all sorts of flat, thin objects, which are transported in almost vertical position, while the time during which they are subject to treatment, is limited by the length of the tunnel.

Fig.1 shows a sheet or plate coating plant a and a belt transport arrangement b to introduce the plates between the wire frames 1 of a continuous transport device c. A discharging device with belt transport arrangement d in the direction of a stacker e is also illustrated.

Fig.2 shows, in a top view, a typical wire frame 1 for a transport device used for the transporting of metal sheets through a drying tunnel. In Fig.3 the same wire frame can be seen in a side view. In Fig.2 a sheet having the maximum length and maximum width is illustrated by dotted lines.

The concept of these wire frames 1 is the result of a compromise between two contradicting requirements, namely: to provide a large and robust support area to support a great variety of sheets and plates of different sizes, and to have a minimal mass to reduce the energy consumption per hour required for the multiple heating up to the processing temperature. The wire frames are usually made from welded or riveted flat steel sections, as picture in Fig. 2. On the other hand, to this date the practice has been that its two surfaces should be parallel, thus enabling problem-free straightening on a rolling plate in case it bends or becomes deformed as the result of a transport mishap (Fig. 3).

These wire frames are installed on one or more chains 2 (Fig. To ensure that the transported sheets lie correctly on that surface which is opposite to the printed or coated side, i.e. on the rear side (so that the front side does not come into contact with the preceding wire frame) the type of fastening of the roughly horizontal wire frames on the chain(s) ensures an angle of 15° between the vertical and the support plane of the wire frame. In well designed transport systems t-shaped parts o*o 3, fastened at the top of the wire frames, serve the purpose of s connection between any two consecutive wire frames. Due to this cage-like arrangement, the wire frames moving in a line, practically cannot get deformed.

Such constructions were completely satisfactory as long as the ratio of the lengths and heights (the dimension of the almost vertical sheet during transport) to its thickness was such that the sheets would not buckle under their own weight and remained supported straight against the wire frames, as this can be seen in Fig. 4, reference numetal 4.

The search for a more effective use of metal led to the 2 i '-IJ 0/ enlargement of the individual sheets and to the reduction of their thicknesses. In case of conventional transport devices the large and thin sheets buckle easily, as this can be seen in Fig. 4 with the reference numeral 5, so that undesirable contacts between the sheet and the rear side of the preceding wire frame will become more frequent. This will result in defective protective and/or ugly spots which render the sheet almost unusable. This tendency is also present in sheets made of light metal, which are less rigid than steel.

From US-A-2,593,415 and US-A-1,736,866 supports for transport devices are known, which transport devices have a carrying run and return run, and which transport flat objects.

The supports of these transport devices are formed flat. The objects are conveyed in the horizontal position to the support-reversal region of the transport device and then raised to a roughly vertical position by the further movement of the :500 conveyor.

The object of this invention is to alleviate the described disadvantages. The invention is based on the recognition that great force needs to be exerted to bend a flat object which is made of a material which has resistance in two mutually perpendicular directions. Indeed, the deformability of the sheet substantially disappears if shaped in different directions. To prevent the bending of a sheet about the horizontal axis also, as illustrated in Fig. 4 by reference 0 numeral 5, it is adequate to bend the sheet about a vertical axis before it is brought into an almost vertical position.

This pre-bending is achieved in a simple manner with the aid of 3

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the wire frames, subject matter of this invention.

According to the present invention there is provided a support for use in a continuous transport device for transporting a flat, thin and flexible object, such as a sheet or plate which has been provided with a fresh surface coating and which is to be transported through a drying tunnel or a tunnel for heat treatment or through a storage area for objects between the two successive processes or the like, the support being movable from a generally horizontal position into a generally upright position, characterised in that the support has a surface on which the flexible object is initially deposited, the surface being shaped in such a manner that the support which receives the flexible object firstly in a generally horizontal position provides it with a pre-bending about an axis which axis is in a vertical plane extending in the S longitudinal direction of movement of the transport device, whereby when the object is elevated into the upright position by the support b ig. the object does not deform about an axis generally perpendicular to the vertical plane.

"Preferably the support is composed of metal sections which are joined together with each other, at least one of the sections having a trapezoidal cross-section so that the shaped surface is produced by abutting the trapezoidal cross-section to an adjacent metal section.

The support may include a central section and outer sections which are mounted to the outer edges of the central section on opposite sides of the vertical plane, the central 4 '"^11 sections and outer sections forming an uninterrupted support for receiving objects with zigzag edges.

In use the support may be mounted to a continuous transport device on chains in such a manner that a sheet or plate constituting the object when deposited on the support is provided with a cylindrical pre-bending, the axis of the cylinder being situated in the vertical r=r^ l plane, =5 and the axis of the cylinder during the transport is either in front of or behind the Z-I i, uf r sheet or plate.

The support may include a central bracket which prevents the falling or slipping of the sheets through the sides of the supports.

:The present invention also provides a continuous transport device for transporting flat, thin, flexible objects supported on a plurality of sequentially arranged supports which support *o S respective objects thereon in a generally upright position, the a o*o objects having a pre-bending about an axis extending in a vertical plane so that the objects do not deform about an axis generally perpendicular to the vertical plane, each of the supports being in accordance with the invention as outlined above.

Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawings. However it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. In the drawings: Fig. 1 shows a schematic side view of a transport device with supports for flat transported objects, Fig. 2 shows a top view of the supports, Fig. 3 shows a front view of a known support, Fig. 4 shows a side view of several supports, Figs. 5, 6, 7, 8, 11 show front views of various embodiments of supports according to the invention, Fig. 9 shows a detailed view of a support, Fig. 12 shows a top view of a support situated in the transport device.

The most basic wire frame (webbed frame, profiled frame) which embodies this invention consists in the bending of a conventional wire frame, thus providing it with a shape which so corresponds to a section of a cylinder, as is illustrated in i5 Fig. 5, or to bend it slightly, so that an open V-shape will occur, as illustrated in Fig. 6. The wire frames according to

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s.e the invention can have lateral extensions pointing upwards (Fig.

7) or downwards (Fig. 8).

*o• In the first three embodiments the wire frame bends the sheet so, that the sides precede the centre of the sheet while being transported in the vertical or almost vertical position.

ges The opposite is the case in the embodiment shown in Fig. 8. The wire frames can bend the sheets in one or another manner, both directions of bending are within the scope of the invention.

25 To facilitate the manufacture of the wire frames shown in see*: Figs. 7 and 8 with conventional tools, the flat rectangular

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steel sections 6, whose purpose is to produce the lateral support extensions 7 (arms), may be replaced by trapezoidal is r sections. This is illustrated in Fig. 9. In this manner the formr lateral support extensions 7 4fm automatically during their manufacture the desired V-shape extending at slightly less than 1800 relative to the centre of the wire frame.

In case it is not feasible to construct the sheet supply (belt transport arrangement b) of Fig. 1 so that the sides of the sheets would be lifted before they are introduced between two wire frames and in case the wire frames are provided with lifted sides, i.e. when the sections are in accordance with Figs. 5, 6 or 7, the construction of the wire frame of Fig. 2 is no longer suitable for the automatic loading of "scrolled" sheets, which have zigzag edges (see dotted line in the centre at the left of Fig. 12, reference number The purpose of the lateral cutouts in these sheets, which one encounters more and more frequently in the metal processing industry, is to prevent 0* metal wastage which occurs when straight cuts are used in the manufacture of objects provided in groups of five on the surface of the sheets for the purpose of lacquering or printing.

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Generally speaking one deals here with round objects, like lids or bottom of cans, or closures, which are manufactured in large quantities and the cost of the material represents a considerable part of the cost price.

The illustration according to Fig. 2 does not satisfy these conditions any longer, because during automatic loading of the sheets, i.e. as soon as they make a translatory movement along the axis of the wire frame there will be the danger of collision between the edges 9 of the scrolled sheets 8 with the lateral support extensions 7, whose outer ends are raised /T .9 7 L^s -w^I relative the central portion of the sheet.

Figs. 11 and 12 show a wire frame which eliminates this disadvantage.

In using such a wire frame the scrolled edges are 1 2 supported by straight and continuous sections 12 and 12 which run parallel to the plane of symmetry of the wire frame and are bent on the outside, so that for example rectangular frames will be produced which can be welded or riveted to a central part 15. This construction is reinforced with the aid of struts 16.

In a preferred embodiment the straight-lined sections 1 2 12 and 12 have an almost trapezoidal cross-section, so that during the assembly an angled surface is automatically obtained, as shown in the section of Fig. 11, whle the frame or frames 5 as well as the struts 16 are still made of steel bars having rectangular cross-section.

goes Fig. 12 shows a wire frame which, for example, has on each slf1 n side two lateral frames 12 1212 This number may be reduced or increased within the scope of the invention. An 1 2 n increase of the number of the sections 12 12 12 o enables the sides of a plurality of sheets having different sizes to be supported. However, the increased mass of the wire o. frame will entail a higher energy requirement during the heating for the process.

1 n Similarly, sections 12 12 with rectangular cross-sections, which can be used for the manufacture of the lateral frames, remain within the scope of this invention in case they have an uninterrupted length parallel to the plane of

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symmetry of the wire frame.

Fig. 11 shows that when the sections 12 have a trapezoidal 1 2 2 n cross-section, each connection 12 12 12 12 forms a new lateral portion of progressively greater angle to the plane of the central part 15 which increases the desired curvature of the sheet towards its edges.

The automatic loading fixtures have devices which slow down and detail each sheet introduced in the transport direction b (Fig. Similarly, the discharge stations d of the same figure are equipped with receiving belts which are often supported by magnetic or other type of rollers. The shape of the wire frame must be such that there would be no obstacles in the path of the loading fixtures or discharge belts.

.The wire frames of this invention satisfy the desired, requirements so that these obstacles can be avoided.

0* In one embodiment the sections and the external 2 n *0 longitudinal frames 12 or 12 do not extend along the 0*00 entire length of the wire frame. This enables the mounting of a magnetic or pneumatic sheet braking device 13, which is shown merely in outlines at the bottom right of Fig. 12.

:00 In another possibility shown in Fig. 12, a large arched 0000 1 cut-out between the sides 12 makes it possible for the sides to pass by the horizontal belts and the associated magnetic and pneumatic rollers, the latter ones pulling out the sheets, which by the movement of the wire frames at the end of the transport S device are pushed down and forwarded to a transporting device 18 indicated by reference d of Fig. 1.

A central bracket 17, which is secured on the frame 15 in such a manner that is passes between two groups of removal belts 14, prevents tall and narrow sheets curved by the shape of the 1 wire frames slipping in between the frames 12 The U-shaped parts 3 which serve as couplings between successive wire frames, are fastened on the horizontal sides of 1 2 n the frames 12 12 12 as can be seen in Fig. 12.

Such a wire frame is connected with the chain 2 by means of tWQ bars which protrude from the sides of the frame These bars engage with the openings of the chain links. In a conventional manner the wire frames are secured by split pins.

Such a wire frame, which provides two opposite faces before the U-shaped parts 3 are attached, can be used to produce a transport arrangement, where the centre of the bent sheet points either forwards or rearwards. Only the mounting of the joining parts 3 determines in which manner the transport arrangement will ol-~irate.

These wire frames are suitable especially for transport arrangements in drying tunnels which are installed in printing 0and lacquering equipment for metal sheets, which, for example, are used for the manufacture of packaging (cans, metal containers, drums, etc.), bottle seals (tops, crown seals) or various metal articles which are manufactured in mass production (plates, toys, games, etc.).

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Claims

1. A support for use in a continuous transport device for transporting a flat, thin and flexible object, such as a sheet or plate which has been provided with a fresh surface coating and which is to be transported through a drying tunnel or a tunnel for heat treatment or through a storage area for objects between the two successive processes or the like, the support being movable from a generally horizontal position into a generally upright position, characterised in that the support has a surface on which the flexible object is initially deposited, the surface being shaped in such a manner that the support which receives the flexible object firstly in a generally horizontal position provides it with a pre-bending j: about an axis which axis is in a vertical plane extending in the longitudinal direction of movement of the transport device, U. whereby when the object is elevated into the upright position by aq.. the support, 1B a- -E 1 .sia the object does not deform about an axis generally perpendicular to said vertical plane.

2. A support according to claim 1, wherein the s'-.)ort is composed of metal sections which are joined together with each *0 other, at least one of said sections having a trapezoidal cross-section so that the shaped surface is produced by abutting the trapezoidal cross-section to an adjacent metal section.

3. A support according to any one of the previous claims wherein the support includes a central section and outer sections which are mounted to the outer edges of the central section on opposite sides of said vertical plane, the central G sections and outer sections forming an uninterrupted support for ai~ receiving objects with zigzag edges.

4. A support according to any nnr of the previous claims wherein the support is mounted to a t utinuous transport device on chains in such a manner that a sheet or plate constituting said object when deposited on said support is provided with a cylindrical pre-bending, the axis of the cylinder being situated in said vertical plane, and the axis of the cylinder during the transport is either in front of or behind the sheet or plate relative to the direction of movement thereof.

5. A support according to any one of the previous claims, wherein the support includes a central bracket which prevents the falling or slipping of the sheets through the sides of the 15 supports.

6. A support substantially as herein described with particular reference to Figs 5 to 11 of the accompanying drawings.

7. A continuous transport device for transporting flat, thin, 20 flexible objects supported on a plurality of sequentially arranged supports which support respective objects thereon in a generally upright position, the objects having a pre-bending about an axis extending in a vertical plane so that the objects do not deform about an axis generally perpendicular to said vertical plane, each of the supports being as claimed in any one of the preceding claims. Dated this 6th day of July 1994 PATENT ATTORNEY SERVICES Attorneys for LTG LUFTTECHNISCHE GMBH Abstract The invention concerns a support, in particular a profiled or wire frame of a continuous transport device for thin and flexible objects, sheets or plates, through a drying tunnel or through a tunnel for heat treatment or the like. This support is characterised by the shape of its surface which accomodates the to-be-transported objects. The aim of this shape is to pre-bend the to-be-transported sheets during their roughly horizontal acceptance, thus preventing their bending under their own weight in the vertical direction, as soon as they are lifted to an almost vertical position before or during the transport. In case of this latter mentioned deformation contact places will occur between the sheets and the preceding frames which have a detrimental effect on the quality of the dried product. (Fig.12)