PLATE-BENDING APPARATUS

TECHNICAL FIELD

The invention is concerned with a plate-bending apparatus, which comprises a body, which has an opening in it for the insertion of the plate, clamps for the holding of the plate, and a bending mechanism for the bending of the plate.

BACKGROUND ART

Plain metal plates are seldom used since the end products usually are in a bent, corrugated, edged or profiled form. Corrugation, profiling etc. is performed to increase the bending resistance. How different materials react to bending can be established by comparing the bending index of different materials. The bending index also significantly increases in, for instance, corrugated board as the cardboard is corrugated.

At present metal plates are coated with a plastic coating, varnish, paint or possibly another metal. Furthermore plates are polished and ground at the factory and are very often delivered in rolls to the customers. The rolls are punched and form pressed or edged into different profile forms, in order to increase their rigidity, so that very thin metal plates still can be used. Typical constructions, such as these, are roof plates, wall profiles, profile plate constructions for concrete pouring, culverts etc. Furthermore, edging, i.e. longitudinal bendings, is performed when manufacturing metallic cupboards, doors, metaiiic wall beams etc.

A machine with which metal plates are bent into permanent forms is one of the most common production machines in the light metal industry.

Fl patent 110491 and US patent 4,181 ,002 are presented as examples of the background art of plate bending machines. In the latter, a large load is formed on the bending point when the plate has been bent 45°.

US patents 6,516,648, 6,640,600 and 5,927,135 are also mentioned as a reference, in which thin plates are bent with an apparatus in which turning ends gliding along the plate bend the plate in a desired angle. This apparatus is therefore not applicable for the bending of coated or otherwise finished plates.

In US patent 6,796,157 non-gliding bending is achieved with a twirling motion. This apparatus can only perform one bending, which dimension is limited to the inner geometry of the apparatus (i.e. about 10 cm).

All the bending machines mentioned above use one or more hydraulic cylinders for power which are attached to a very rigid bending beam which provides power.

The invention is presented in the following using figures, which are not intended to limit the invention which has been defined in the claims.

SUMMARY OF THE INVENTION

The plate bending apparatus of the invention has a body, with an opening in it for the insertion of the plate, clamps for the holding of the plate, and a bending mechanism for the bending of the plate. The clamps consist of holding damps and bending clamps, which are attached to each other with a flexible fixing agent, which bends and stretches as the plate is bent.

The advantageous embodiments of the invention have the characteristics of the sub claims.

Therefore, the apparatus also has a fibre enforced elastomeric belt, which has been placed between the plate and the clamps. There is, advantageously, also a pressurised tube inside

the flexible material that connects the clamps in order to achieve the bending of the plate. The bending mechanism consists of air beams which when filled bend the clamps in order to bend the plate. The clamps have grooves for a porous air pipe, which erupts the pressurised air from the air pipes between the plate and the clamps as the plate moves. Therefore the plate does not have direct contact to the solid parts of the clamps during the bending.

The bending means of the plate-treatment apparatus is according to the invention either connected to the holding clamps by means of an elastomeric polymer material or the plate- bending clamp or the bending button is of elastomer material, the properties and/or dimensions of which as well as the friction coefficient are such that no gliding takes place at the holding point between the plate and the bending button. The elastomer used can be of polyurethane, rubber or some other flexible technical polymer. In this way, no paint, varnish or other coating or surface layer will get damaged on the surface of the plate.

The bending apparatus of the invention is inexpensive and it can be used for bending metal plates, cardboard etc. without scratching the surface. The surface is not rubbed in such a way that the surface is scratched, broken or damaged. The desired effect has been accomplished in the invention by the "stretching hinge" of the bending clamps.

With the invention, a continuous and even distribution of force can be achieved for the length of the bending area, a release of the plate from the mechanic touch to the parts of the bending apparatus as it moves from one phase to another and a bending clamp that does not scratch the plate or plate-like product.

The bending apparatus of the invention is not limited with regards to the amount of bendings done on the same plate and it is also faster than other similar apparatuses.

The use of pressurised air instead of hydraulics is advantageous when handling a thin metal plate. Energy can easily be stored and pressurised air flows quickly from one space to another. This means that the pump or compressor does not have to perform all the work during the handling since energy can be taken from the pressurised air storage.

FIGURES

Figure 1 presents a general view of the bending apparatus of the invention

Figure 2 presents the bending point of the plate, in the bending apparatus of the invention, before the bending of the plate, in the phase where the plate has been inserted into the bending apparatus

Figure 3 presents the bending point of the plate, in the bending apparatus of the invention, during the bending of the plate, in the phase where the plate has been bent

DETAILED DESCRIPTION

In figure 1 a general view of the plate-bending apparatus of the invention is presented. The plate-bending apparatus comprises a body, which has an opening 5 for the insertion of the plate 6. The plate is in practice inserted on a plate table 7. The plate 6 is held by clamps 8.

The body of the plate-bending apparatus consists for example of two joint elements 1a, 1b shaped as the letter C. The space 2 between the C-letters in the body can be used as storage for pressurised air, in which pressurised air cylinders 14 have been placed. The inside space of the part shaped as the smaller C-letter 1b functions as the insertion space 4 for the plate being still unbent. The plates can be put into the handling position from the open side of the space which is shaped like the letter C. The space 2 between the two different sized C-shaped spaces, which can be used as storage for pressurised air, can be outfitted with enforcing plates with holes in them.

A slitter 13 can be installed in the plate-bending apparatus, the rotating blade of which slitter cuts the bent part away from the fabricate plate when the plate-bending bending clamps (described more in detail in figures 2 and 3) are in a straight position.

The bending point is shown in more detail in figure 2. Figure 2 presents the situation before the bending of the plate in a phase in which the plate 6 has been inserted into the bending apparatus. The plate 6 is held with clamps 8 (which are entirely visible in figure 1). The

clamps 8 have been constructed of two metal clamps A1 , B1 and two turning bending clamps A2, B2.

The clamps, of which A1-B1 are holding clamps and A2-B2 are bending clamps, have been attached to each other with elastomer 9 in such a way that A1-A2 are parts of the same product, which can be changed in such a way that the length of the elastomer, i.e. the distance between the metal parts of the damps can be changed. A longer distance allows for a larger radius of bending. A lot of different radii of bending can be achieved with the pressurised liquid pipe inside the clamps, a belt with a varying thickness in between and the length of the elastomer between the clamps.

The elastomer material 9 between the clamps A1 , A2 stretches and squashes during the bending of the plate. The A1 and A2 clamps do not move in relation to the plate 6. The A, B clamps can also advantageously be at least partially covered with elastomeric material.

The elastomer 9 between the clamp series A and B can be pre-stretched e.g. with a pressurized fluid. The pre-stretching results in a change in the radius of the angle of the plate to be edged. The pressurized fluid is preferably in the fibre-reinforced hose 3, left in place at point 3, when the elastomer has been cast. The radius of bending of the turning angle of the plate to be edged can in some extent be adjusted with the pressure of the water or other fluid.

The holding clamps A1-B1 are consequently in a fixed but stretching connection to the bending clamps, which bending clamps A2-B2 furthermore are simultaneously on both sides and thus form stoppers to each other.

In the invention, torque is provided by pressurised air beams 11 , which are filled with pressurised air, thus bending the clamps. Clamps A, B have grooves 10, in which there is a flexible and porous pipe 3, which is activated with pressurised air whenever the plate is moved in the direction of the clamps and from which holes air erupts that releases the direct rubbing contact between the clamps and the handled (bent) plate 6.

Pressurised air can be used partly at least twice when handling the plates. This means that, when the plate proceeds from one working phase to another, the pressurized air, or preferably the waste pressurized air, is lead via such porous means or fluidization means, which, by means of the pressurized air, keep the plate mechanically separate from e.g. the metal surfaces. With waste pressurized air is meant the air, which erupts from the working cylinder or working bellow when its pressure valve is opened after the work phase. The waste pressurized air can be taken for use when according to the invention the pressurized air from the bellows, of which there is one for each series, is pre-pressurized an completely compact, working as a "spring", which blows the other bellows empty for the next work phase. When the air is moving out from the primary power bellows or cylinder, it moves via said porous means in a place, wherein the plate moves from the foregoing work phase to the next position, e.g. for the next bending or the plate is removed from the edging machine. When the edging machine is loaded with the next plate fabricate, pressurized air is blown from the corresponding places, which then is always primary air.

Figure 3 presents the bending point in the bending apparatus of the invention during the bending of the plate, in the phase where the plate already has been bent. Figure 3 also illustrates the embodiment with which accurate and larger radii of bending can be achieved. There is a fibre enforced belt 12 between the plate and the clamps, in the embodiment of figure 3, with which the radius of bending can be adjusted by varying the thickness of the belt. The belt is advantageously endless, circulating on two wheels, and which can have for instance three different degrees of thickness, for instance 1 , 2, 3 mm. The belt is advantageously porous, so that an insertion and ejection movement of the handled plate can be achieved without rubbing.

Figure 3 illustrates the beams 11 filling with air, which leads to the bending of the clamps. Clamps A, B have grooves 10, in which there is a flexible and porous pipe 3, which is activated with pressurised air whenever the plate is moved in the direction of the clamps, and from which holes air erupts which releases the direct rubbing contact between the clamps and the handled (bent) plate 6.