FIELD OF THE INVENTION

The present invention concerns a device to automatically pick up at least one or more metal bars from at least a bundle of bars, disposed in at least a container, to make them subsequently available to a working machine such as a bracket- making machine, a bending machine, a shaping machine, a binding machine or other type of similar machine.

The present invention also concerns the corresponding removal method to pick up the bars.

BACKGROUND OF THE INVENTION

Machines for working metal bars are known, which work one or more bars at a time, for example to make shapes for the building trade or other types of product. Such machines are served by storage zones which normally have one or more containers, for example disposed on transfer trolleys, in which the bundles of bars are disposed and from which they are picked up on each occasion to be sent for working.

It is often very difficult to pick up and remove the individual bars from the bundle since the bars, which can often reach lengths of up to 12m and more, arrive loose, and get entangled and twisted.

The pick-up operation is carried out manually by an operator and requires a considerable effort from him, with the risk that he might get hurt and also slowing the operative cycle, thus reducing the productivity of the subsequent workings.

A machine is also known which comprises lifting means which lift a plurality of bars from a bundle, gripping them near their center line.

The end segments of the bars, which usually remain twisted inside the bundle, are subsequently and progressively extracted with extractor means, which comprise two rollers mounted on guides which are disposed parallel to the extension of the bundle of bars and on a plane coinciding with the lifting plane of the bars when using magnetic lifting means.

Specifically, when the lifting means have lifted the bars in the center, the two rollers, disposed respectively on one side and the other of the lifting mean, are then moved reciprocally away, and with respect to the lifting means, along the guides, to progressively release also the end segments of the bars which may be twisted in the bundle.

The known device however, has the disadvantage that, during the movement of the rollers, the bars can be released only at one end, while the other end may remain jammed in the bundle, causing an unbalancing of the bar, which can take it into a condition of interference with parts of the device. In some cases the operator may be required to intervene, in order to reestablish the correct functioning conditions.

Another disadvantage of the known machine is that, because of the great effort which is needed to extract the bar from the bundle, the latter can be deformed in an irregular way with respect to its rectilinear extension.

Another disadvantage of this pick-up device is that a great effort is needed to extract the bar completely from the bundle, and long cycle times and complex and costly equipment are required.

A machine which substantially works with this principle is described in FR-A- 2.526.769.

Other solutions are also known, from EP-A2-774.427 and DE 3921 350 CI for example, which provide a lifting device and extraction means, using rollers for example, mounted on a chain and mobile ring-wise to progressively lift the bar or bars held temporarily raised. The lifting device of these solutions is not suitable to move the bar longitudinally, so that the rollers have to travel the entire length of the bar and extract it completely from the bundle, in order to allow it to be unloaded. Moreover, since the bar that has to be extracted is longitudinally stationary, the rollers and the chain which moves them are subjected to great stresses and friction which determine early wear and risk of damage.

One purpose of the present invention is to obtain a device to pick up at least one bar from the bundle which automates the extraction, without requiring the intervention of an operator, which is simple, economic, needs little or no maintenance and has a reduced initial investment.

Another purpose of the present invention is to obtain a device which allows the extraction of bars from the bundle without the use of excessive efforts and with reduced cycle times.

Another purpose of the present invention is to pick up the bars even two or more at a time, preventing them from being subjected to deformation that could reduce them to a deformed condition.

Another purpose is to perfect a method to pick up automatically at least one bar from a bundle of bars and make it available to a working machine while maintaining the bar in any case rectilinear.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purposes, a device to pick up at least one bar from a bundle of bars comprises at least a lifting unit suitable to lift at least an end segment of the bar with respect to the bundle, and an extractor unit suitable to extract the bar, the end of which is held raised by the lifting unit, from the bundle.

According to one feature of the present invention, the lifting unit comprises at least gripping and retaining means suitable to retain at least the end segment of the raised bar at least temporarily, and drawing means able to move the bar, the end of which is held raised by the lifting unit, in a first direction, while the extractor unit comprises a plurality of extractor elements suitable to be moved, in at least an operating condition thereof, between the bars of the bundle stationary in the container and the raised end segment of the bar to be picked up, and to be then progressively moved in a second direction opposite to the first direction, that is, away both from the raised end of the bar and from the lifting unit, moving toward an end of the bar opposite to the raised end segment. In this way the extractor element or elements can progressively release the whole segment of the bar still inside the bundle, raising it, while the drawing means of the lifting unit move the bar in the first direction opposite the second direction of movement of the extractor elements. Therefore, according to the invention, after the lifting of the end of the bar, the latter is also progressively extracted from the bundle making it slide longitudinally to its longitudinal extension, in this way preventing any deformations thereto, reducing the cycle time and the stresses and the friction to which the extractor elements are subjected as they move along the bar.

According to another form of embodiment, the extractor unit comprises transmission members such as belts, chains or suchlike, disposed at the sides of the bundle of bars, suitable to support the extractor elements so that they extend substantially transversely with respect to the longitudinal extension of the bundle, and suitable to move the extractor elements in a selective manner in order to take them respectively from below to above the bundle and vice versa, in a travel around the end segment of each of the bars disposed in the bundle. In this way, as the extractor elements gradually proceed in the opposite direction to the direction of feed imparted to the bars by the drawing means, they both progressively remove them from the bundle and also support them, keeping them substantially on the same plane on which the drawing means act.

The movement from below to above of the extractor elements with respect to the bundle, achieving a return travel which develops completely under the bundle, does not create any interference between the extractor elements and the bars in the bundle, so that the movement and the picking up can take place substantially continuously, without pauses and without downtimes.

In particular, when the extractor elements are disposed below the bundle, it is possible to allow the lifting unit to lift the end of the bar without problems of interference, and subsequently it is possible to begin their progressive insertion between the bar and the bundle so as to achieve its extraction.

According to another form of embodiment, the extractor elements comprise idle rollers associated with transmission members, along which the bars can slide. This further reduces the friction between the extractor elements and the bar as its extraction from the bundle gradually proceeds.

According to another form of embodiment, when disposed above the bundle the rolls define an inclined plane with an inclination which allows to unload the bar, once it has been completely extracted from the bundle, toward an unloading zone where subsequently, using other movement means, the bars picked up are made available for subsequent workings.

According to another form of embodiment, an inclined plane is disposed downstream of the lifting unit, and it is able to receive at least a part of the completely extracted bar when moved by the drawing means, and to unload it toward the unloading zone.

According to another form of embodiment, the gripping means are chosen from a group comprising at least a magnetic element and mechanical grippers.

The present invention also concerns the corresponding method for picking up at least one bar from a bundle of bars, which comprises at least a step of lifting at least an end part of the bar and at least a step of extracting the bar from the bundle.

According to one feature of the method, during the lifting step, the bar is lifted at least partly, gripping it by means of a lifting unit in proximity to an end segment thereof, and made to move in a first direction by means of a drawing unit, while, during the extraction step, a plurality of extractor elements are disposed between the bundle and the end segment which was lifted during the lifting step, and are moved in a second direction, opposite to the first direction, away from both the end segment and from the lifting unit toward an end of the bar opposite to the end segment.

According to another form of execution, during the extraction step the extractor elements, disposed transversely to the longitudinal extension of the bundle, are moved by means of transmission members such as belts, chains or suchlike, which are disposed at the sides of the bundle, respectively from below to above the bundle and vice versa, in a travel around the end segment of each of the bars which are disposed in the bundle.

According to another feature of the method, the extractor elements define a plane inclined toward the unloading zone, and after the extraction step the bar is unloaded due to gravity toward the unloading zone.

BRIEF DESCRIPTION OF THE DRAWINGS

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

- fig.1 is a three dimensional view of the device to pick up at least a metal bar according to the present invention;

- fig. 2 is a three dimensional view of a detail of fig. 1 ;

- fig. 3 is a perspective view of the device in fig. 1 in a first operating configuration;

- fig. 4 is a perspective view of the device in fig. 1 in a second operating configuration;

- fig. 5 is a perspective view of the device in fig. 1 in a third operating configuration;

- fig. 6 is a perspective view of the device in fig. 1 in a fourth operating configuration;

- fig. 7 is a perspective view of the device in fig. 1 in a fifth operating configuration.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings.

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF

EMBODIMENT

With reference to fig. 1, a device to pick up at least one metal bar B is indicated in its entirety by the reference number 10 and comprises, in its essential parts, a store 1 1 containing a plurality of bundles F of metal bars B, a lifting unit 12 to lift an end segment 25 of at least one of the bars B, an extractor unit 13 to extract the bar B from the bundle F, and an unloading zone 15 to unload the bar.

The store 1 1 comprises, in a known manner, a plurality of sacks 16 inside which the bundles F, in this case six, are disposed parallel to each other.

In particular, the end segments 25 of the bars of the bundle F facing toward the lifting unit 12 are disposed cantilevered so that due to their own weight they bend downward.

The lifting unit 12 comprises gripping and retaining means suitable to lift and retain at least temporarily the raised end segment 25, and drawing means 33 suitable to move the raised bar B in a first direction of feed Dl .

A bearing structure 17 is suitable to support not only some of the sacks 16 containing bundles F, but also the extractor unit 13 and the lifting unit 12.

The bearing structure 17 extends longitudinally for about two thirds of the overall length of the bundles F, covers the entire width of the store 11 and is disposed so that at least the end segments 25 of the bundles F are comprised inside its overall bulk.

The bearing structure 17 comprises a first side 23 and a second side 24, disposed in proximity to, and substantially at the same height as, the unloading zone 15, and having a height reduced with respect to the first side 23.

The extractor unit 13 is associated to the bearing structure 17, and comprises, on each side 23 and 24 of the bearing structure 17, a transmission member, in this case a chain 19 on which a plurality of supports 20 are attached, in this case four, suitable to support, in an idle manner, with the mating supports 20 disposed on the opposite side of the bearing structure 17, rollers 21a, 21b, 21c, 2 Id which extend transverse to the extension of the bundle F and for the entire width of the store 1 1.

The chain 19 is mounted sliding on toothed wheels 22 and is driven in a known manner by motor members not shown in the drawings.

In particular, the rollers 21a, 21b, 21c, 21d are selectively movable in a second direction of feed D2, parallel to the extension of the bearing structure 17 in an alternate manner, so as to be disposed either above or below the bundles F. In other words, the rollers 21a, 21b,21c, 2 Id may be translated from a position in which they are under the bundles F, to a position in which, passing at the side of the end segments 25 of the bars B, they are taken above the bundles F.

The second direction of feed D2 is opposite to the first direction of feed Dl in which the bar B is extracted by the drawing means 33.

The chain 19 which is associated to the first side 23 is disposed at a greater height than that of the chain 19 which is associated to the second side 24, so that when they are disposed above the bundles, the rollers 21a, 21b, 21c and 21d are all inclined at an angle of inclination a toward the unloading zone 15 of the device 10, to define a plane π inclined with respect to the ground: the inclined plane π has an inclination substantially transverse to the longitudinal development of the bars B.

An inclined plane 29 is associated to the terminal part of the bearing structure 17, substantially having the same inclination as the rollers 21a, 21b, 21c and 2 Id.

Solely as an example, the angle of inclination a of the rollers 21a, 21b, 21c and 21d of the inclined plane 29 is comprised between 10° and 60°. In order to reduce the picking up stresses of the lifting unit 12, it is advantageous to provide that the chain 19, and therefore the rollers 21a, 21b, 21c and 2 Id associated with it, in proximity to the end segments 25 of the bundles F, are constrained to follow an inclined development downward, to be disposed substantially parallel to the end segment 25 which in this condition is curved because of the effect of the actual weight of the bundle F.

In a similar way, the sacks 16 which contain the bundles F are disposed at different heights from each other so that, moving from the first side 23 toward the second side 24, they are inclined too by the same angle of inclination a.

The lifting unit 12 is associated to the inclined plane 29 by means of a support bracket 32; the lifting unit comprises an articulated arm 30 to the end of which a magnetic element 31 is associated, suitable to lift at least one bar from the bundle F, and the drawing means 33 suitable to move the bar or bars B forward, which are lifted by the articulated arm 30 toward the inclined plane 29, that is, in the first direction D 1.

In other forms of embodiment, instead of providing to use a magnetic element for picking up, it is possible to use mechanical grippers or other gripping and/or holding members.

The support bracket 32 extends parallel to the longitudinal extension of the bundles F to allow the articulated arm 30 to pick up the bar B at most at a distance of about a third from its end, with respect to the whole of its length.

The magnetic element 31 is disposed in a mainly transverse direction to the longitudinal development of the bars B lying in the respective sack 16, and advantageously has a width such as to cover the whole width of the bundle F. The support bracket 32 is selectively sliding, transversely to the longitudinal disposition of the bundles, along a guide 35 associated to the inclined plane 29, and also disposed inclined by the same angle of inclination a of the latter. In this way it is possible to translate the lifting unit 12 transversely to the longitudinal extension of the bundles F in order to allow the articulated arm 30 to be disposed in correspondence to one of the bundles F.

The drawing means 33 comprise two motorized rollers 36 disposed below, and another two contrast rollers 37, above, which are selectively translatable using actuators to take them to grip the bar B and toward the motorized rollers 36. Specifically, the articulated arm 30 selectively takes the magnetic element 31 into contact with the bars B of one of the bundles F in order to lift an end segment 25 of at least one bar B at least to the same height as the motorized rollers 36 of the drawing means 33. During this lifting operation a slight translation is also provided, to allow the raised bar B to be disposed inside the drawing means 33 and on the motorized rollers 36. Subsequently, the contrast rollers 37 are pressed onto the bar B to keep it clamped, and driving them it is possible to make the bar B move forward toward the inclined plane 29.

It is clear that the motorized rollers 36 are disposed at least at the same height as the inclined plane π, in order to allow the bar B, when it has been translated, to be disposed on the inclined plane 29.

The functioning of the device to pick up bars according to the present invention is described hereafter (figs. 3-7). For easier understanding, we shall describe how one bar is picked up, even though it must be understood that, using the device according to the present invention, several bars can be picked up at the same time.

The bundles F of bars are disposed inside the sacks 16 of the store 1 1, so that respective end segments 25 of the bars B are disposed cantilevered inside the bearing structure 17.

In this condition, all the rollers 21a, 21b, 21c and 21d are disposed below the bundles F, and the bearing structure 17 is accessible from above in order, for example, to allow the correct positioning of the bundles F in the sacks 16.

Subsequently the lifting unit 12 is selectively translated along the guide 35 to move into cooperation with one of the bundles F from which the bars B are picked up.

The articulated arm 30 is driven to take the magnetic element 31 into contact with the end segment 25 of one of the bars, and then lifted to a height substantially equal to that of the inclined plane π to dispose the bar B on the motorized rollers 36.

The contrast rollers 37 are pressed against the motorized rollers 36 to maintain the bar B clamped between them.

Then the rollers 21a, 21b, 21c and 2 Id are made to translate in the second direction D2 to move in succession above the bundles F. Specifically (fig. 4), since the bar B is in a raised position and gripped by the drawing means 33, the roller 21a is moved to an intermediate position between the bundle F from which the bar has been picked up and the end segment 25 of the bar B.

Continuing the translation of the chain 19 in the second direction D2 and keeping the bar B clamped between the drawing means 33, the roller 21 exercises a lifting action on the bar B which tends to detach it from the bundle F.

During this step the motorized rollers 36 of the drawing means 33 are also driven, which provide to translate the bar B toward the inclined plane 29, that is, in the first direction Dl . The advancing of the bar B allows to reduce the pick-up stresses, thus preventing the bar from becoming deformed. Indeed with this solution sliding friction is reduced to a minimum, which generates considerable deformations in the bar, while rolling friction that causes chafing between one bar and the next, acting longitudinally on the bar, does not cause particular deformations.

Continuing the drive of the chains 19, the rollers are moved in succession toward the upper part of the bearing structure 17 and in this way they release the bar from the bundle.

The main action of extraction is thus carried out by the roller 21a and by the drawing means 33, which move the bar B forward and extract it from the bundle. The other rollers 21b, 21c and 21d substantially have the function of supporting the bar to define the inclined plane π.

When the roller 21a reaches its maximum travel, that is, when it is located near the terminal part of the bearing structure 17, similarly to what is shown in fig. 7, the bar B is completely extracted from the bundle F and advanced with respect to the latter, by a length substantially equal to the longitudinal extension of the inclined plane 29.

In this condition, the bar B, still gripped in the drawing means 33, is released and, due to the effect of the inclination of the rollers 21a, 21b, 21c and 2 Id, and of the inclined plane 29, is unloaded toward the unloading zone 15 (fig. 1) from which suitable movement means, not shown in the drawings, may render it available for subsequent workings.

To carry out the subsequent extraction of another bar B, the rollers 21a, 21b, 21c and 2 Id are again taken below the bundles F, making them repeat the travel inverse to the one described above.

It is clear that modifications and/or additions of parts may be made to the device to pick up at least one metal bar as described heretofore, without departing from the field and scope of the present invention.

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