Automatic loader and separator apparatus for elongate semi-finished products for feeding a user machine

Abstract

An automatic loader and separator apparatus (1) for elongate semi-finished products (2), for feeding a user machine, comprises a load-bearing feeder structure (7), for receiving the semi-finished products (2), which is provided with at least two operating units (38), which are positioned at a distance from each other along a horizontal lying line (X) of at least one said semi- finished product (2). The operating units (38) comprise an upright (32) supporting in a substantially vertical plane (Y,Z) and projecting substantially transversally to the upright (32), at least one arm (20) with two prongs (11,12), and at least one flexible funicular element (24) subtended between free ends (29,30) of the prongs (11,12). Said at least one flexible funicular element (24) is placed below at least one said semi- finished product (2), and operates between two limit conditions, in one of which it is configured with a curved arrangement between the prongs (11,12), in the other condition in contrast it being taut between the prongs (11,12) in such a way that a substantially straight branch (25) of the flexible funicular element (24) is defined to support resting on it at least one said semi-finished product (2) and to transfer it onto the receiving feeder structure (7).

Description

[0001] AUTOMATIC LOADER AND SEPARATOR APPARATUS FOR

[0002] ELONGATE SEMI-FINISHED PRODUCTS FOR FEEDING A USER MACHINE

[0003] Technical field

[0004] This invention relates to an automatic loader and separator apparatus for elongate semi- finished products , for example bars or pipes , for feeding a user machine , in particular a machine tool .

[0005] Background art

[0006] In the field of mechanical machining operations involving the shaping of obj ects by removal of material performed with machine tools , starting from elongate semi- finished products such as bars or pipes , use is known of feeding apparatuses , which are devised to receive , handle and trans fer to the machine tool such elongate semi- finished products , which are positioned with their longitudinal dimension oriented so that it is lying substantially hori zontal .

[0007] According to one technology, known and described in document IT 102020000018145 , by the same Applicant , such semi- finished products arrive at the feeding apparatus contained in special crates with an open bottom, from which - by means of a double system of shoulders , some fixed and others movable , appropriately operating in conj unction in relative movement with the crate - the semi- finished products are gradually extracted from the crate and sent in an orderly manner to the receiving machine tool .

[0008] More speci fically, the crates , which substantially have the shape of an elongate parallelepiped, are made to rotate around their hori zontal longitudinal axis by relative actuator means .

[0009] The shoulders are placed in an initial condition near open sections of the bottom and arranged substantially at a tangent to the profile of the transversal outline of the crate .

[0010] As the crate rotates , due to the movement of the crate relative to the shoulders , the shoulders themselves , intersecting with the open sections of the bottom, intercept the semi- finished products contained in the crate , take the weight of the semi- finished products on themselves and gradually move them away from the bottom, simultaneously moving them towards the top opening of the crate .

[0011] Having reached the top opening of the crate , with its continued further rotation, the semi- finished products are definitively pushed out of the crate and trans ferred in an orderly manner, parallel to themselves , to feed the receiving machine tool .

[0012] The solution described above has proved particularly effective and advantageous relative to the pre-existing prior art ; however, it is mechanically highly complex, with high production and management costs .

[0013] Disclosure of invention

[0014] The purpose of this invention is therefore to provide a feeding apparatus which eliminates those disadvantages .

[0015] As part of that purpose , a first aim of the invention is to provide a feeding apparatus which is capable of automatically loading the bars completely independently of external loading means , and of separating the automatically loaded semi- finished products in a way that is mechanically simpler, but is highly ef ficient and reliable , as well as flexible and adj ustable , depending on a wide variety of parameters , such as : dimensions , own weight , surface state and geometric regularity and material of the semi- finished products themselves .

[0016] A second aim of the invention is to provide relatively simple mechanical solutions capable of reducing the construction costs and operating management costs of such an apparatus , compared to prior art solutions similarly provided for feeding elongate semifinished products to a machine tool .

[0017] A third aim is to provide an apparatus capable of serving, without the need for speci fic equipment , a wide variety of di f ferent machine tools .

[0018] A fourth aim is to provide an apparatus capable of proactively interacting, without particular interfacing di f ficulties , with complex automation systems , even relating to entire departments of machine tools , i f necessary of types di f ferent from each other .

[0019] Accordingly the invention achieves those results with an automatic loader and separator apparatus for elongate semi- finished products for feeding a machine tool , whose technical features are defined in the following claims .

[0020] Brief description of drawings

[0021] Further features and advantages of the invention will be apparent from the detailed description of an example , non-limiting embodiment of the invention, shown in the accompanying drawings in which :

[0022] Figure 1 is an assembly drawing of an apparatus according to the invention shown in a three-dimensional axonometric view, with a bundle of elongate semifinished products prepared for feeding a receiving machine tool , not illustrated;

[0023] Figure 2 is an assembly view of a first variant of the apparatus of Figure 1 , seen from a di f ferent angle ;

[0024] Figure 3 is a three-dimensional assembly view of a second variant of the apparatus of Figure 1, shown with the bundle of semi-finished products removed to better illustrate some parts of the apparatus itself;

[0025] - Figure 4 is a three-dimensional view of the apparatus shown with some parts cut away to better illustrate others ;

[0026] - Figure 5 is a side view of the apparatus of Figure 4;

[0027] Figure 6 is a view of a feeder structure of the apparatus of the preceding figures shown with some parts cut away to better illustrate others;

[0028] Figures 7 and 8 are enlarged sides views of a particular system of shoulders, with which the apparatus is equipped, and seen from opposite sides;

[0029] Figures 9 and 10 are side views of the shoulders of Figures 7 and 8 shown in two different operating arrangements ;

[0030] Figure 11 is a side view of an alternative embodiment of the shoulders of Figures 9 and 10;

[0031] Figures 12 and 13 are two axonometric views of several details of the invention shown in two different operating arrangements and with some parts cut away to better illustrate others;

[0032] Figure 14 is an axonometric view of the details of Figure 13 seen from a different viewpoint;

[0033] Figure 15 is a side view of the details of Figure 11 seen from an opposite viewpoint.

[0034] Preferred embodiments of the invention

[0035] With reference to the figures of the accompanying drawings, in Figure 1 the numeral (1) denotes an automatic loader and separator apparatus (1) for elongate semi-finished products (2) for feeding a user machine .

[0036] The semi-finished products (2) can be identified, for example, as bars, pipes and the like, used to supply the material to be machined to a generic machine tool, for example to a lathe, which is not shown in the drawings, not being part of this invention.

[0037] The apparatus (1) essentially comprises two structures (3,7) , respectively a carriage structure and a feeder structure, which are operatively interconnected with each other.

[0038] A first structure, labelled (3) , comprises a carriage (13) , movable on wheels (42) , provided with two fixed supports (4) , spaced apart, along a first longitudinal line (X) of the feeding apparatus (1) .

[0039] The second, feeder structure (7) , also preferably movable on wheels (43) , comprises three operating units (38) , for automatic loading of at least one semi-finished product (2) , which are positioned a suitable distance from each other along a horizontal line (X) parallel to the lying line of at least one said semi-finished product (2) .

[0040] The operating units (38) , for automatic loading, operate in vertical planes (Y,Z) , transversal to the horizontal longitudinal line (X) , parallel to which, one or more semi-finished products (2) in a bundle are advanced to the apparatus (1) .

[0041] The operating units (38) comprise, in particular (Figures 7 - 15) , an upright (32) which supports in a substantially vertical plane (Y,Z) and projecting transversally to the upright (32) , an arm (20) with two prongs (11,12) , as well as at least one flexible funicular element (24) , such as a belt, cable or chain, subtended between free ends (29,30) of the prongs (11,12) of said arm (20) .

[0042] The flexible funicular element (24) is intended to be placed below at least one semi-finished product (2) and to operate between two limit conditions, in a first of which it is configured with a curved arrangement between the prongs (11,12) ; in the second condition in contrast the funicular element (24) being taut between the prongs (11,12) in such a way that a substantially straight branch (25) , of said flexible funicular element (24) is defined to support resting on it at least one said semi-finished product (2) and then to transfer it onto the receiving feeder structure (7) .

[0043] Figures 2 and 3, seen in comparison to Figure 1, show two possible variants of the apparatus.

[0044] A first variant (Figure 2) shows how the carriage structure (3) can be moved relative to the ground by driving means which comprise for example a special drive robot (41) suitable for making it movable from one location to another in the room in which the apparatus (1) is placed.

[0045] In a second variant of the apparatus (1) shown in Figure 3, in contrast the feeder structure (7) , as well as being movable on wheels (43) , can be self-propelled using driving means powered by electric batteries accommodated in housings (44) made in the feeder structure (7) itself.

[0046] Obviously, by appropriately combining the different embodiments of the carriage structure (3) and the feeder structure (7) , the apparatus (1) can be configured to be capable of feeding: either a specific machine tool, or in sequence and separately various machine tools in a machining department .

[0047] Figures 4 and 5 in particular show that the fixed supports (4) of the carriage (13) which must accommodate, for example semi-finished products (2) with a circular profile, preferably have a bottom (10) provided with a concave surface suitable for supporting resting on it one or more semi-finished products (2) , if necessary gathered together in a bundle.

[0048] The semi-finished products (2) are substantially grouped around a median plane (Y,Z) of the support (4) , and in a condition in which they can project from both sides of it and longitudinally to the line (X) with at least two substantially horizontal stretches (6) , defining free spans, completely surrounded by space without any obstacles.

[0049] The semi-finished products (2) having a circular profile in cross-section (as in the example described) can therefore be constrained to remain on the supports (4) by lateral stops (5) in the form of suitable shoulders, or side walls: which project vertically, confining the semi-finished products (2) along their sides, and which, preferably, are integrated in a single body with and continue on from the bottom (10) of the respective supports (4) .

[0050] Figure 6 shows how, in the feeder structure (7) , in each operating unit (38) a prong (11) of the arm (20) is placed in a position proximal to at least one respective upright (32) and in combination with it delimits a sorting station (9) for said semi-finished products (2) . From that sorting station (9) the semi-finished products (2) , which arrived from the straight branch (25) , are then transferred in an orderly manner, parallel to themselves, along and to a top (33) of the upright (32) . When they have passed beyond that top, the semi-finished products (2) are then sent, with their orientation unchanged, to feed the user machine.

[0051] The upright (32) preferably defines an oblique path relative to the vertical line (Y) , tilted back towards the taut branch (25) of said flexible funicular element (24) , along which the semi-finished products (2) are intended to move gradually away from the sorting station (9) .

[0052] Said oblique path may be defined either by giving the upright (32) a predetermined inclination relative to the vertical, as shown in the figures of the accompanying drawings; or, alternatively, but in a functionally equivalent way, by means of a structural configuration of the apparatus (1) in which the upright (32) has a vertical structure, but with which a path is associated comprising an oblique linear stretch of trajectory, along which the semi-finished products (2) translate.

[0053] That can be achieved, for example, by means of a suitable structure assigned to a looped conveyor chain, for conveying the semi-finished products (2) along the vertical upright (32) .

[0054] Figures 7 - 10 show, more specifically, how each automatic loading unit (38) comprises effector means (8) which include an already mentioned flexible funicular element (24) , which, according to a first embodiment shown in Figures 9 and 10, is configured to have a branch (25) of its longitudinal length subtended between two ends labelled (26,27) , and which is suitable for adopting a curved or straight configuration depending on what is necessary for the automatic loading unit (38) .

[0055] In fact, a first end (26) may be kept permanently or, alternatively, temporarily in a fixed motionless condition; the permanently fixed condition may be achieved by anchoring said end (26) to a fixed point of the structure of the arm (20) ; alternatively, the temporary condition may be achieved in an equivalent way by anchoring the end (26) to the periphery of a rotary pulley (14) , but with rotation around its axis selectively prevented by the action of a braking unit (for example as shown in Figures 7 and 8) .

[0056] Once the first end (26) has been locked in place, one way or the other, the second end (27) can then be subjected to a traction action, against the antagonistic reaction of the first end (26) , however it is applied.

[0057] As a result of the traction action, the branch (25) may therefore adopt a variable arrangement between the above-mentioned two limit configurations: a curved first configuration, with concave arc (Figure 9) directed towards the semi-finished products (2) , suitable for loading the semi-finished products (2) onto it; the second configuration, in contrast, being taut, in a substantially straight arrangement.

[0058] In the first condition, the semi-finished products (2) can be grouped around the centre line of the arc surrounding the bundle of semi-finished products (2) ; in the other condition, the semi-finished products (2) may in contrast be distributed flat and separate, that is to say, positioned side by side without being superposed on each other, also being able to be moved translating parallel to themselves and above a support with a substantially flat surface.

[0059] A different embodiment, shown in Figure 11, in contrast has an alternative configuration in which the flexible funicular element (24) - rather than being made in a single branch - is instead wrapped in a loop around a multi-sided path here defined by arranging three pulleys (28,14) located at the vertices of the multisided path. Two pulleys are rotatable around their own fixed axis of rotation (28a) , at least one being motor- driven; the third pulley (14) in contrast is freely rotatable around its own axis of rotation (14a) , movable in the vertical plane (Y,Z) .

[0060] Figures 12 - 15 show that the prongs (11,12) of the arms (20) preferably support in combination with each other three axles (19) on which the same number of pairs of pulleys (28; 14) are mounted.

[0061] Two flexible funicular elements (24) , closed in a loop are coupled in parallel with each other and are positioned on both sides of an interposed arm (20) .

[0062] A further alternative embodiment could even be made with, for each automatic loading operating unit (38) , positioning of a single funicular element (24) housed between two arms (20) which are on both sides of and adjacent to said funicular element (24) .

[0063] As regards the mechanical structure of the arms

[0064] (20) , it can be inferred from the figures that, according to a preferable example, non-limiting embodiment, the arms (20) have a curved, concave shape, preferably an arc of a circle.

[0065] The prongs (11,12) are movable as a continuation of each other and translatable circumferentially in a guide (18) one relative to the other.

[0066] The apparatus (1) further comprises actuator means

[0067] (21) for actuating the relative movement of said prongs (11,12) between two limit conditions, in a first of which a movable prong (12) is retracted, in a non-operating position, on the fixed prong (11) (Figures 7, 8 and 12) ; in the other, operating condition, said movable prong (12) in contrast being brought into a position in which it forms a longitudinal continuation of the fixed prong (11) , as shown in Figures 9 - 11, 14 - 15.

[0068] More specifically, the guide (18) comprises a pair of sliders (16) , shown by way of example in the form of pins, which are borne by one of the prongs (12) of the arm (20) and a pair of grooves (17) borne by the other prong (11) .

[0069] The sliders (16) and the grooves (17) engage with and translate relative to each other, to allow the transition of the movable prong (12) relative to the fixed prong (11) to the retracted configuration and, vice versa, to the extended, lengthened configuration.

[0070] The grooves (17) are geometrically profiled to implement a guided path of the sliders (16) according to a law of relative shifting, between the movable prong (12) and the fixed prong (11) , so as to impart to the branch (25) of the flexible funicular element (24) the maximum tension upon reaching the configuration in which said prongs (11,12) are positioned in the condition of maximum elongation of the arm (20) .

[0071] Regarding the actuator means (21) for that function, Figures 12, 13 and 15 clearly show how said means (21) comprise a gearwheel (22) and a rack (23) shaped to match it which mesh with each other, one and the other being respectively borne by one and the other of said prongs (11,12) .

[0072] In use, operation of the apparatus (1) is described starting from an initial condition of Figure 1 which shows a group of semi-finished products (2) gathered in a bundle, which are supported in a horizontal arrangement on a pair of fixed supports (4) , borne by a carriage (3) movable on wheels (42) .

[0073] The carriage (3) is drawn near the fixed feeder structure (7) of the apparatus (1) with orderly arrangement of its supports (4) between three consecutive arms (20) , longitudinally to the horizontal line (X) .

[0074] In that initial condition, the arms (20) are configured with their movable prongs (12) completely retracted and superposed on the respective fixed prongs (11) , said arms (20) being placed at stretches (6) of semi-finished products (2) which are supported cantilever-style by the supports (4) longitudinally to the horizontal line (X) . As a consequence of full retraction of the movable prongs (12) on the respective fixed prongs (11) (Figures 2,7 and 8) , the flexible funicular elements (24) are closed in a substantially slack loop which, at the branch (25) positioned between the corresponding ends (26,27) of the fixed and movable prongs (11,12) , has a curved very concave shape on the side directed towards the semifinished products (2) .

[0075] As a result of suitable commands issued to the actuator means (21) , the movable prongs (12) then gradually come out relative to the fixed prongs (11) , whilst the looped shape of the funicular elements (24) starts to tighten.

[0076] As the curvature of the branch (25) is gradually reduced, the bundle leaves the supports (4) of the carriage (3) , its weight being taken by the flexible funicular elements (24) of the individual arms (20) .

[0077] It should be noticed that if the drive unit of the driving pulley (28) of the flexible funicular elements (24) (or of a toothed pinion (40) meshing with a chainshaped flexible element (24) ) is started before the movable prongs (12) reach the maximum cantilever extension from the fixed prongs (11) , due to the combination of simultaneous effects including on one hand the concavity of the branch (25) and on the other the simultaneous circumferential sliding of the flexible funicular element (24) , the semi-finished products (2) loaded on the branch (25) may adopt a motion revolving on themselves, without moving forward, which makes them repeatedly fall back onto the bundle and which, advantageously, allows re-arrangement and alignment of the semi-finished products (2) of the bundle, even if they were to have irregularities in their local or general structure. Having reached the condition in which the movable prong (12) has completely come out relative to the fixed prong (11) , the loading branch (25) for the semi-finished products (2) adopts a position in which maximum tensioning of the branch (25) is achieved.

[0078] Preferably, the shape and the extension of the prongs (11,12) of the arms (20) is such that it puts the respective pulleys (28,14) vertically out of alignment.

[0079] Therefore, the branch (25) is oblique relative to the line (Z) and inclined, downwards, towards the sorting station (29) .

[0080] This leads to two fundamental advantages: the first advantage is flat layering, without superposing of the semi-finished products (2) of the bundle, which guarantees correct separation of the semi-finished products (2) ; the second advantage is in terms of energy, since tilting back the branch (25) allows a reduction in the energy necessary for the orderly transfer of the semi-finished products (2) on the sorting station (9) .

[0081] Once the semi-finished products (2) have reached the sorting station (9) , they are lifted, translating along the upright (32) and towards the top (34) of the upright, as already indicated. However, it should be noticed that due to the oblique nature of the path along the inclined upright (32) , should it accidentally be the case (Figures 9 - 11) that two superposed semi-finished products (2) were to occupy a same single seat provided for them to use individually in the lifting means, between the upper semi-finished product (2) and the lower semi-finished product (2) a position eccentricity would be created which would cause the former to have to leave the seat, due to gravity, and to fall back onto the branch (25) restoring the conditions for regular individual transfer of one semi-finished product (2) at a time.

[0082] The oblique nature of the transfer path along the upright (32) , that is to say, the positioning at an acute angle of the path along the upright (32) and of the branch (25) , at the sorting station (9) , therefore advantageously contribute to activating a further step of separation of the semi-finished products (2) .

[0083] A further advantage of those features can be recognised in the fact that, where the oblique nature of the transfer path for the semi-finished products (2) along the upright (32) is obtained by tilting back the structure of the upright (32) itself, the apparatus (1) would have as a whole, along the line (Z) , a horizontal dimension much smaller (around 50% less) than that of prior art apparatuses for performing similar tasks serving a receiving machine tool.

[0084] That, in general, is particularly significant; and even more so in those production departments, or in those workshops, where there is limited floorspace in which to install various machine tools.

[0085] Further advantages are also obtainable, observing that if the carriage structure (3) - which bears the fixed support (4) for the semi-finished product (2) or for the bundle of semi-finished products (2)- is devised in such a way as to be self-propelled from one place to another in a work department (for example, by means of the movement robot (41) on the ground as shown in Figures 2 and 4) it becomes possible to use a single self- propelled carriage structure (3) to serve, in sequence, a plurality of user machines of an entire department, each equipped with its own relative feeder structure (7) provided with only the automatic loading operating units (38) .

[0086] From that we can immediately establish: on one hand, a signi ficant reduction in costs for equipping the entire production department ; and, on the other hand, the possibility of fully automating in a highly flexible way the supplying of materials towards the user machines of an entire department .

[0087] Moreover, i f the possibility of also moving the feeding structure ( 7 ) on its own wheels ( 43 ) is used, the fact that a single apparatus ( 1 ) can be used, in turn on a plurality of user machines of a same department , allows a considerable reduction in the cost of investment in machinery, improving ef fective use of the apparatuses ( 1 ) and reducing the internal space occupied in production departments .

[0088] The invention ful fils the aims previously indicated . Moreover, in addition to the advantages already expressed, it is also relatively simple and inexpensive to build, in conclusion with the possibility of full automation and easy integration and interfacing with the machine tools for which it is intended .

Claims

CLAIMS1. An automatic loader and separator apparatus for elongate semi-finished products (2) for feeding a user machine, characterised in that it comprises a load-bearing feeder structure (7) , for receiving the semi-finished products (2) , which is provided with at least two operating units (38) , which are positioned a suitable distance from each other along a horizontal lying line (X) of at least one said semi-finished product (2) ; said operating units (38) comprising an upright (32) which supports, in a substantially vertical plane (Y,Z) and projecting transversally, at least one arm (20) with two prongs (11,12) , as well as at least one flexible funicular element (24) subtended between free ends (29,30) of the prongs (11,12) of said arm (20) ; said flexible funicular element (24) being placed below at least one said semi-finished product (2) and operating between two limit conditions, in one of which it is configured with a curved arrangement between said prongs (11,12) , in the other condition in contrast it being taut between said prongs (11,12) in such a way that a substantially straight branch (25) , of said flexible funicular element (24) , is defined to support resting on it at least one said semi-finished product (2) and to transfer it onto said receiving feeder structure ( 7 ) .

2. The apparatus, according to claim 1, characterised in that one prong (11) of said arm (20) is proximal to said upright (32) and in combination with it delimits a sorting station (9) for said semi-finished products (2) , the semi-finished products (2) which arrived from saidstraight branch (25) in said station (9) then being transferred in an orderly manner along the upright (32) as far as a top (33) , beyond which, the semi-finished products (2) are sent to feed the user machine.

3. The apparatus, according to claim 2, characterised in that said upright (32) defines an oblique path relative to the vertical line (Y) , tilted back towards the taut branch (25) of said flexible funicular element (24) , along which the semi-finished products (2) move away from the sorting station (9) .

4. The apparatus, according to claim 1, characterised in that said arm (20) has a curved shape.

5. The apparatus, according to claim 1, characterised in that the prongs (11,12) of the arm (20) are movable in a guide (18) relative to each other; said apparatus further comprising actuator means (21) for actuating the relative movement of said prongs (11,12) between two limit conditions, in one of which one movable prong (12) is retracted in a non-operating position on the fixed prong (11) , in the other, operating condition, said movable prong (12) being brought into a position in which it projects from the fixed prong (11) .

6. The apparatus, according to claim 1, characterised in that said funicular element (24) has one end (26) held stationary and is wrapped around at least one motor- driven rotary pulley (28) , whose drive unit is controlled in such a way as to suitably modulate the configuration of said flexible funicular element (24) between said limit conditions, respectively curved and taut.

7. The apparatus, according to claim 1, characterised in that said flexible funicular element (24) is wrapped in a loop around at least one pair of pulleys (14,28) .

8. The apparatus, according to claim 1, characterised in that said prongs (11,12) have complementary lengthsand conform to an assembly profile on which said branch (25) of the flexible element (24) , in its traction condition, adopts a substantially straight arrangement.

9. The apparatus, according to claim 1, characterised in that said free ends (29,30) of the prongs (11,12) are vertically out of alignment to give said branch (25) , an oblique and inclined arrangement, tilted back down towards said feeder structure (7) .

10. The apparatus, according to claim 1, characterised in that said at least one pair of pulleys (28,14) comprises a motor-driven pulley (28) and a freely rotatable pulley (14) borne respectively by said prongs (11,12) .

11. The apparatus according to claim 1, characterised in that it comprises at least three pulleys (28;14) , at least one of which is motor-driven, which are placed on said two prongs (11,12) of the arm (20) , said flexible funicular element (24) , being wrapped in a multi-sided loop around said at least three pulleys (28; 14) .

12. The apparatus, according to claim 2, characterised in that said guide (18) comprises a pair of sliders (16) borne by one of the prongs (12) of said arm (20) and a pair of grooves (17) borne by the other prong (11) , said sliders (16) and said grooves (17) engaging with and translating relative to each other, to allow the transition of said movable prong (12) relative to the fixed prong (11) to the retracted configuration and, vice versa, to the extended configuration, as a result of the action imparted by relative actuator means (21) .

13. The apparatus, according to claim 12, characterised in that said grooves (17) are profiled to implement a law of relative shifting of said movable prong (12) and fixed prong (11) so as to impart to said branch (25) of the flexible funicular element (24) the maximum tensionupon reaching the configuration in which said prongs(11.12) are positioned in the condition of maximum elongation of said arm (20) .

14. The apparatus, according to claims 12 or 13, characterised in that said actuator means (21) comprise a gearwheel (22) and a rack (23) shaped to match it which mesh with each other, one and the other being respectively borne by one and the other of said prongs(11.12) .

15. The apparatus, according to one of the preceding claims, characterised in that said pulleys (28,14) are coupled, in pairs, on a single axle (19) , being supported on both sides by said arm (20) .

16. The apparatus, according to claim 1, characterised in that it comprises a movable structure (3) provided with at least one fixed support (4) , above which said at least one semi-finished product (2) is supported lying horizontally and in a condition in which it can project from both sides of it and longitudinally to said line (X) , with at least two substantially horizontal stretches (6) , said movable structure (3) operating in conjunction with two said automatic loading units (38) , which are associable with said fixed support (4) on both sides and below said horizontal stretches (6) .

17. The apparatus according to claim 16, characterised in that said at least one fixed support (4) is provided with a concave bottom (10) , suitable for keeping a plurality of said semi-finished products (2) gathered together around a median plane (X,Y) of said at least one fixed support (4) .

18. The apparatus, according to claim 16 or 17, characterised in that a single said structure (3) is devised to reach and to serve a plurality of user machines, each of which comprises a said feeder structure(7) equipped with at least one said operating unit (38) .

19. The apparatus, according to claim 1, characterised in that said feeder structure (7) is movable on wheels (43) .

20. The apparatus, according to claim 19, characterised in that said structure (7) is self-propelled driven by its own autonomous driving means.

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