Bending machine for metal products and corresponding bending method

Abstract

Bending machine for one or more metal products such as, for example, bars (11a, 11b), reinforcement round pieces, structural shapes, tubes or other profiles, comprising at least a bending unit, a main drawing unit, able to draw the bar along an axis of advance toward the bending unit, and a main shearing unit disposed between the bending unit and the main drawing unit. The machine also comprises a secondary drawing or extraction unit disposed between the main drawing unit and the main shearing unit. The secondary drawing or extraction unit is configured and programmed to draw an end portion of bar, exiting from the main drawing unit, along the axis of advance toward the bending unit.

Claims

1. Bending machine for a metal product, comprising a bending unit, a main drawing unit able to draw said metal product along an axis of advance toward said bending unit, and a main shearing unit disposed between said bending unit and said main drawing unit, said machine also comprising a secondary drawing or extraction unit disposed between said main drawing unit and said main shearing unit, said secondary drawing or extraction unit being configured and programmed to draw an end portion of the metal product exiting from said main drawing unit along said axis of advance toward said bending unit, and further comprising a secondary shearing unit of the bilateral type disposed between said secondary drawing or extraction unit and said main drawing unit, and wherein said secondary shearing unit of the bilateral type comprises a pair of upper blades associated with respective lower blades, wherein a first upper blade is located on one side of the bilateral shears facing toward the main drawing unit, whereas a second upper blade is located on another side of the secondary shearing unit facing toward the secondary drawing or extraction unit.

2. Bending machine as in claim 1, wherein said upper blades are able to interfere with a first guide element for said metal product made in said secondary shearing unit.

3. Bending machine as in claim 1, wherein at least one of either said main drawing unit or said secondary drawing or extraction unit is commanded by a central control and command unit.

4. Bending machine for a metal product, comprising a bending unit, a main drawing unit arranged to draw the metal product along an axis of advance toward said bending unit, and a main shearing unit disposed between said bending unit and said main drawing unit, said machine also comprising a secondary drawing or extraction unit disposed between said main drawing unit and said main shearing unit, said secondary drawing or extraction unit being configured and programmed to draw an end portion of the metal product exiting from said main drawing unit along said axis of advance toward said bending unit, and further comprising a secondary shearing unit of the bilateral type disposed between said secondary drawing or extraction unit and said main drawing unit; wherein said bilateral shears comprise a pair of upper blades associated with respective lower blades, wherein a first upper blade is located on one side of the bilateral type shearing unit facing toward the main drawing unit, whereas a second upper blade is located on another side of the bilateral type shearing unit facing toward the secondary drawing or extraction unit; wherein said upper blades are able to interfere with a first guide element for said metal product made in said secondary shearing unit of the bilateral type; and wherein said secondary drawing or extraction unit comprises at least a second guide element, the second guide element being substantially tubular and arranged to facilitate the advance of said metal product along said axis of advance.

5. Bending machine as in claim 4, wherein said second guide element comprises an entrance with an inclined profile to facilitate the entrance and advance of said metal product along said axis of advance.

6. Bending machine as in claim 4, wherein said secondary drawing or extraction unit includes a thrust means comprising rollers, and wherein second guide element has at least one aperture able to allow the cooperation between the thrust means of said secondary drawing or extraction unit and said metal product.

7. Method to bend metal products using a bending machine comprised of a bending unit, a main drawing unit, a main shearing unit disposed between said bending unit and said main drawing unit, and a secondary drawing or extraction unit disposed between said main drawing unit and said main shearing unit, and comprising the following steps: a first step in which said main drawing unit draws a first one of the metal products along an axis of advance until said first one of the metal products exits from said main drawing unit, a second step in which only said secondary drawing or extraction unit draws said first one of the metal products along said axis of advance toward said bending unit for bending, a third step in which said main drawing unit draws a second one of the metal products along said axis of advance and toward said bending unit for bending, a fourth step in which said second one of the metal products thrusts said first one of the metal products along said axis of advance in order to discharge it from the axis of work of the bending machine.

8. Method as in claim 7, and further providing a step of head-wise or tail-wise butting of the first one and the second one of the metal products, performed by a secondary shearing unit of the bilateral type disposed between said secondary drawing or extraction unit and said main drawing unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other characteristics of the present invention will become apparent from the following description of some forms of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

(2) FIGS. 1-7 show schematically a bending machine according to the present invention, during a sequence of working steps;

(3) FIG. 8 is a variant of the bending machine in FIGS. 1-7.

DETAILED DESCRIPTION OF ONE FORM OF EMBODIMENT

(4) With reference to FIGS. 1-7, a bending machine 10, shown only partially, according to the present invention is used for bending metal products such as for example bars, reinforcement round pieces, structural shapes, tubes or other profiles with any section shape whatsoever.

(5) Hereafter in the description, the word bar shall be understood to include both bars and reinforcement round pieces, structural shapes, tubes or other profiles with any section shape whatsoever.

(6) The bending machine 10 is configured so as to selectively work one or more bars simultaneously.

(7) Hereafter in the description, the bars will be identified generically by the reference number 11. Given that the bars 11 are inserted and worked in sequence, one after the other, a first bar introduced will be identified by the reference number 11a, while the bar introduced after 11a will be identified by the reference number 11b.

(8) In this case, the bending machine 10 comprises a bending unit 12, in this case a disc, able to bend one or more bars 11, a main shearing unit or shears 13, disposed upstream of the bending disc 12 and able to finish or rather shear the bent bars 11, eliminating the excess parts thereof with respect to the linear development of the segment formed, and a main drawing unit 14 with pairs of rollers 15, able to make the bars 11 advance along an axis of advance X toward the bending disc 12.

(9) The bending disc 12, the main shears 13 and the main drawing unit 14 can be of any type, which is not restrictive for the purposes of the present invention.

(10) In this case, the main shears 13 comprise an upper blade 13a and a lower blade 13b, at least one of which is mobile to perform the shearing to the desired size.

(11) According to the invention, the bending machine 10 also comprises, between the main drawing unit 14 and the main shears 13, secondary shears of the bilateral type 17 and a secondary drawing or extraction unit 19. In some forms of embodiment, at least one of either said main drawing unit 14 or said secondary drawing or extraction unit 19 is commanded by a central control and command unit. The secondary drawing or extraction unit 19 is advantageously disposed upstream of the main shears 13, with respect to the bending disc 12, in a position near the main shears 13.

(12) The secondary bilateral shears 17 comprise a first lead-in channel 18 provided with a first truncated cone-shaped inlet 21 able to facilitate the insertion and subsequent advance of the bars 11. The secondary bilateral shears 17 also comprise two upper blades 17a and 17b associated with respective two lower blades 17c, 17d, at least one of which, for each pair, is mobile to selectively interfere with the first channel 18. As can be seen in the drawings, in this case the upper blade 17a is associated with the lower blade 17c and is located on one side of the bilateral shears 17 facing toward the main drawing unit 14, whereas the other upper blade 17b is associated with the lower blade 17d and is located on the other side of the bilateral shears 17 facing toward the secondary drawing or extraction unit 19.

(13) Using secondary bilateral shears, with two upper blades 17a and 17b and two respective lower blades 17c and 17d, allows to use, as will be seen, said blades to perform respectively, one to butt the head-ends of the bars 11, and the other to butt the tail-ends of the same bars 11.

(14) The secondary drawing or extraction unit 19 can comprise thrust means, in this case rollers 20. The secondary drawing or extraction unit 19 is driven at least when the bar 11 is no longer gripped by the main drawing unit 14.

(15) The secondary drawing or extraction unit 19 comprises a second lead-in channel 22 disposed between the rollers 20, which is provided with a truncated cone-shaped inlet 23 which facilitates the alignment and insertion of the bars 11, and with apertures 24 that allow the rollers 20 to cooperate with the bars introduced into the second channel 22.

(16) If there are two or more bars 11 in parallel, there are respectively two or more channels 18 and 22, one for each bar 11, in the secondary bilateral shears 17 and the secondary drawing or extraction unit 19.

(17) The bending machine 10 as described heretofore functions as follows.

(18) In a first step (FIG. 1), the first bar/bars 11a is/are introduced in a known manner between the rollers 15 of the main drawing unit 14.

(19) Hereafter in the description we shall refer to two bars 11a inserted in a pair, of which only one is visible in the drawings, although the possibility of working one or more than two bars 11a is not excluded.

(20) The main drawing unit 14 draws the bars 11a along the axis of advance X as far as the bilateral shears 17. In particular, during this step, the first bars 11a are butted, that is, the respective head-ends are equalized and aligned, on the upper blade 17a of the bilateral shears 17, which is in a low position and thus functions as an abutment surface for the first bars 11a. In this way, the bars 11a are aligned with their front end.

(21) According to a variant, the butting of the first bars 11a can be carried out on one of the blades 13a or 13b of the main shears 13, in the same way as happens with the bilateral shears 17.

(22) In a second step (FIG. 2), the upper blades 17a, 17b of the bilateral shears 17 open and the main drawing unit 14 draws the first bars 11a to the bending disc 12 by means of which stirrups or other semi-worked shaped products are formed, according to usual work cycles.

(23) During this step, the bars 11a are made to pass through the bilateral shears 17 and the secondary drawing or extraction unit 19, without the latter intervening. In particular, the first bars 11a pass through the first 18 and second channel 22 which guide them as far as the bending disc 12.

(24) In this step, according to a variant, the secondary drawing or extraction unit 19 can act, if suitably synchronized by means of the command and control unit, in addition to the main drawing unit 14, to provide greater traction to the first bars 11a.

(25) Also during this step, the main shears 13 shear the bars 11a drawn by the main drawing unit 14, using the upper blades 13a and lower blades 13b, and according to determinate intervals of time, for example regular, so as to obtain a plurality of semi-worked products, for example all having the same sizes.

(26) In a third step (FIG. 3), the tail or rear end 16a of the bars 11a exits from the main drawing unit 14, then the bars 11a are no longer gripped by the main drawing unit 14. The secondary drawing or extraction unit 19 is then driven, since the main drawing unit 14 is no longer able to draw the first bars 11a.

(27) The secondary drawing or extraction unit 19 allows to continue working on the remaining segment of the bars 11a between the main shears 13 and the main drawing unit 14.

(28) This allows to limit the quantity and length of the offcuts, which entails a reduction in waste and an economic benefit.

(29) Furthermore, if the distance between the main shears 13 and the main drawing unit 14 is different from the length of one of the semi-worked products previously obtained, it is possible to obtain from the same bending machine 10 at least two types of product, in the sense of products with different lengths.

(30) During the third step, the main shears 13 act in the same way as in the second step.

(31) The secondary drawing or extraction unit 19 takes the tail-ends 16a of the first bars 11a to a sufficient distance to guarantee they are butted tail-wise on the upper blade 17b of the bilateral shears 17, located in a lowered position.

(32) If only one bar 11a is being worked, the tail-wise butting is useful so as to know the state of advance of the bar 11a.

(33) If two or more bars 11a are worked in parallel, the tail-wise butting is necessary for the subsequent steps, as will be described hereafter in the description.

(34) In a fourth step (FIG. 4), the secondary drawing or extraction unit 19 continues drawing the bars 11a to a predetermined size. In particular, the fourth step is concluded when the bars 11a are stopped in a determinate position in which their tail-ends 16a are a little before the secondary drawing or extraction unit 19. At this point, the portion of bar 11a remaining defines the offcut to be discharged.

(35) During the fourth step too, the main shears 13 can shear the bars 11a to regular segments in order to obtain a plurality of semi-worked products.

(36) In a fifth step (FIG. 5), similar to what we saw before, second bars 11b are introduced into the main drawing unit 14 and are butted head-wise on the upper blade 17a, which is in a low position, of the bilateral shears 17.

(37) In a sixth step (FIG. 6), the upper blades 17a of the bilateral shears 17 open and the main drawing unit 14 draws the second bars 11b until they enter into contact with the stationary first bars 11a, that is, with the segments thereof to be discharged, unless the machine 10 provides to make small shaped products which can be obtained starting from said segments of first bars 11a.

(38) According to a first solution, the fifth and sixth steps are subsequent to the third and fourth steps.

(39) According to a variant, the fifth and sixth steps can take place partly or completely simultaneously with the third and fourth steps, thus obtaining a saving in terms of cycle times.

(40) In a seventh step (FIG. 7), the second bars 11b thrust the segments of the first bars 11a along the axis of advance X in order to complete the working and possibly to expel the offcuts, which are represented by the final segment of the bars 11a.

(41) It is therefore important to perform an adequate tail-wise butting, as in the previous steps, of the bars 11a and 11b, so that the head-ends of the second bars 11b enter into contact with the tail-ends 16a of the first bars 11a at the same time and at the same height, without misalignment, so as to have a uniform thrust.

(42) Therefore, according to the invention, the offcuts are expelled along the axis of advance X substantially automatically and easily, without interference with the work units of the bending machine 10. Furthermore, manual intervention by the operator is avoided, thus limiting the risk for the operator of suffering injures and/or accidents.

(43) Advantageously, the presence of the secondary drawing or extraction unit 19 allows to make, with the same bending machine 10, stirrups and semi-worked products having different sizes, thus increasing productivity. This is because, as we said, small-size shaped products can be obtained using the segments of bar not gripped even by the secondary drawing or extraction unit 19, obtaining the feed of such segments to the bending disc 12 by thrusting the bars fed for the subsequent work cycle.

(44) This also entails a limit to the offcuts, since the length of the segments of the bars that cannot be worked is reduced.

(45) It is clear that modifications and/or additions of parts may be made to the bending machine 10 and bending method as described heretofore, without departing from the field and scope of the present invention.

(46) It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of bending machine and method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.