A sheet-metal bending machine

Abstract

 The present invention relates to a sheet-metal bending machine. It comprises a fixed support structure (1) bearing a lower pressing element (3) on which the sheet (4) to be bent is placed and to which lower pressing element (3) a mobile upper pressing element (5) is associated; the machine also comprises a mobile frame (9) bearing a lower blade (11) and an upper blade (10). Said blades (10) and (11) perform the bending of the sheet (4) when the mobile frame (9) is raised or lowered. The mobile frame (9) is furthermore able to slide away from and towards the said sheet (4) by means of an activating system comprising at least one cam device (14), to which a connecting element (16) with the mobile frame (9) is solidly fixed, which cam device (14) is able to rotate in both directions according to pre-established and automated operative phases.

Description

[0001] The invention relates to a sheet-metal bending machine.

[0002] In particular, the machine is best applied in the bending of metal sheets of differing thicknesses, of satin-finish stainless steel, or prepainted sheets, or plasticated sheets and so on, which are destined for widely differing uses, such as, for example , in the construction of metallic furniture, the cases of household electrical appliances, shelves, etc., in which the bending zones of the sheet, the paint or the protective layer must be without defects.

[0003] The prior art embraces sheet-metal bending machines of different types able to avoid the formation of defects in the bending zone.

[0004] Said machines comprises a fixed suporting structure having two pressing elements: one fixed lower element, on which the sheet to be bent is placed, and one mobile upper element, which keeps the sheet pressed on to the lower element. A mobile frame, having a substantially c-shaped transversal section, is associated with the fixed element, which frame has two blades, one upper and one lower, which blades, following the raising or lowering of the mobile frame effect the bending of the sheet.

[0005] To avoid the formation of defects in the bending zone, and in order to be able to carry out bendings with different angles as well as roundings of the said bending angles, a movement of the mobile frame is envisaged, both away from and towards the sheet to be bent.

[0006] The prior art embraces a first type of machine in which said movement is realised by means of the use of manual adjustment systems. The well-known drawback of these machines is constituted by the fact that correct execution of the bending depends largely on the operator's ability.

[0007] The prior art embraces also a second type of machine, in which the bending blade's movement away from and towards the sheet is executed envisaging that the blades should be moved singly. That, as is well known, considerably complicates the machine from the point of view of construction. The machine also becomes extremely complex and expensive and difficult to control in that there are two movement directions to manage (one for each bending blade).

[0008] The prior art also embraces a third type, in which the movement towards and away from the blade is made by the entire mobile frame. The movement system in this case is cosntituted by hydraulic cylinders. The well-known drawback of such machines is that the hydraulic cylinders cannot carry out micrometric movements with great accuracy. In pratice, therefore, the positioning of the mobile frame carrying the two blades is insufficiently precise and furthermore is difficult to manage.

[0009] The principal aim of the present invention is therefore that of overcoming the above-cited drawback relative to prior art machines, and of providing a sheet-metal bending machine capable of operating on sheets of different thicknesses, avoiding the formation of defects in the bending zones, and of realising bending angles with the possibility of rounding them: said machine is extremely simple from the point of view of construction, extremely precise, reliable and easy to manage from the operative point of view, and can be operated automatically.

[0010] The aim and others besides are attained by the machine in question, comprising essentially a fixed support structure having a lower pressing element, on which the sheet to be bent is placed, to which lower element a mobile upper pressing element is associated which upper element presses the sheet to be bent against said lower element, said upper pressing element being supported by a mobile structure, said machine further comprising a mobile frame, borne by said support structure, having a substantially c-shaped transversal section bearing an upper blade and a lower blade, said blades effecting the bending of the sheet while said mobile frame is raised and lowered, activating means being envisaged to effect said raising and lowering of said mobile frame, said mobile frame being furthermore able to slide from and towards the sheet to be bent by means of an activating system, wherein said activating system comprises at leats one cam device to which a connecting element to said mobile frame is solidly fixed, said said cam device being mounted on a shaft able to perform rotations in both directions with excursions determined by pre-established operative phases.

[0011] Further characteristics and advantages of the invention will better emerge from the detailed description which follows, of a preferred but not exclusive embodiment herein illustrated purely in the form of a non-limiting example in the drawings, in which:

• Figure 1 shows schematically and in side view the present invention without its side-cover;
• Figure 2 shows schematically, in isometric projection, the posterior part of the machine with several parts taken away;
• Figures 3, 4, 5, and 6 show schematically four bending phases of the sheet effected by the lower blade.

[0012] With reference to the drawings, a support structure 1 has internally a chamber 2. The support structure 1 has a lower pressing element 3 on which the sheet 4 to be bent is placed, to which lower pressing element 3 a mobile upper pressing element 5 is associated which presses the sheet against the lower pressing element 3.

[0013] The upper pressing element 5 is borne by a mobile structure, hinged 7 to the support structure 1, which support structure 1 is able to perform vertical-plane oscillations by the activating of at least one double-acting hydraulic cylinder 8 which is fixed respectively to the mobile structure 6 and to the support structure 1.

[0014] Inside the chamber 2 a mobile frame 9 is housed, having a substantially c-shaped transversal section, and bearing an upper blade 10 and a lower blade 11.

[0015] The blades 10 and 11 effect the bending of the sheet 4 when the mobile frame 9 is raised or lowered: the blade 10 or the blade 11 interferes with the sheet 4 in proximity to the zone where it exits from the pressing elements 3 and 5, effecting thus the bending: the upper blade 10 effects the downwards bending, while the lower blade 11 performs the upwards bending.

[0016] The raising and lowering of the mobile frame 9 is performed by at least one double-acting hydraulic cylinder 12 constrained to the mobile frame 9 and to the support structure 1.

[0017] The mobile frame 9, which is pivoted on a shaft 13 positioned in the posterior part of the support structure 1, is also able to slide horizontally away from and towards the sheet 4 by means of a particular activating system. Said activating system comprises at leats one cam device 14, formed by a plate element 15 splined on the shaft 13, to which shaft 13 a connecting element 16 to the mobile frame 9 is solidly fixed.

[0018] The mobile frame 9 is thus pivoted on the shaft 13 by the cam device 14.

[0019] The shaft 13, activated by known means, is able to perform rotations in both directions with excursions determined by pre-established operative phases for example, 100° in one direction and 100° in the opposite direction) controlled by a computer (not in the figures).

[0020] Said computer furthermore manages all the other movements of the machine, permitting of a programmable funtioning, according to the operative requirements , which is completely automatic.

[0021] In figures 3, 4, 5,and 6 four phases of bending of the sheet 4 are illustrated by way of example.

[0022] In fig. 3 the moment of positioning of the blade 11 in relation to the sheet 4 is represented.

[0023] In fig. 4 the vertical activating of the blade 11 is represented, bringing about the formation of a bend greater than 90°.

[0024] In fig. 5 the horizontal activating of the blade 11 is represented (produced by the rotation of the shaft 13 and consequently of the cam device 14) bringing about the formation of a bend with a 90° angle.

[0025] In fig. 6 a further horizontal displacement of the blade 11 is represented , bringing about the formation of a bend with an angle of less than 90°.

[0026] It is notable that form the point of view of construction and functioning the present machine is very simple, and as a result of this will be very economical to run, and will cause few operative problems.

[0027] The invention therefore attains the pre-established aims.

Claims

1. A sheet-metal bending machine, comprising essentially a fixed support structure (1) bearing a lower pressing element (3) on which element (3) a sheet (4) to be pressed is placed, to which element (3) a mobile upper pressing element (5) is associated, which upper pressing element (5) presses the sheet (4) to be bent against said lower pressing element (3), said upper pressing element (5) being borne by a mobile strucutre (6); said machine further comprising a mobile frame (9), borne by said support structure (1), having a substantially c-shaped transversal section, bearing an upper blade (10) and a lower blade (11), said blades (10) and (11) effecting the bending of the sheet (4) when said mobile frame (9) is raised or lowered; means of activation (12) being envisaged to effect the raising or lowering of said mobile frame (9), said mobile frame (9) being furthermore able to slide away from and towards the said sheet (4) by means of an activating system; wherein said activating system comprises at least one cam device (14) to which device (14) is solidly fixed a connecting element (16) with said mobile frame (9), which cam device (14) is mounted on a shaft (13) able to rotate in both directions with excursions determined by pre-established operative phases.

2. A machine as in claim 1, wherein said mobile frame (9) is pivoted on said shaft (13) at the position of said cam device (14).

3. A machine as in claim 1, wherein said cam device (14) comprises a plate element (15) splined on said shaft (13).

4. A machine as in claim 1, wherein said activating means (12) envisaged for the effecting of the raising and lowering of the said mobile frame (9) comprise at least one double-acting hydraulic cylinder (12) constrained respectively to said mobile frame (9) and to said fixed support structure (1).

Drawing