Patent Description:
The safety device can be used on a column or a segment of column that functions as a support for a lifting apparatus, such as a goods hoist or elevator or work platform, used on a construction site.

Furthermore, the safety device can be used in combination with said lifting apparatus mounted on said column or said segment of column.

In addition, the safety device can be used in all those vertical constructions that are modularly mounted from the bottom upward.

The lifting apparatus can be used in construction sites, shipyards, civil engineering yards, and in all yards where there is a need to build to considerable heights and wherever it is necessary to use lifting means for transporting objects and/or people.

The lifting apparatus can also be used in emergency situations, where it is necessary to quickly prepare a lifting system that allows the vertical movement of objects and/or people.

The safety device and lifting apparatus can be used on any vertical structure that is part of a system for lifting objects and/or people.

The safety device and lifting apparatus can be used whenever there is a need to verify the stability of a bearing column to support a system for lifting objects and/or people.

The method can be used during the installation and/or disassembly of a vertical structure to support a system for lifting objects and/or people.

The method can be used to verify the stability of a bearing column supporting a system for lifting objects and/or people.

It is known that in recent decades the world of construction and/or maintenance has seen a considerable development in the construction of buildings or structures that reach considerable heights, from several tens up to several hundred meters.

The construction or maintenance of buildings or structures that reach such heights has created the need to develop new systems for lifting objects and/or people, mainly used on sites during construction or maintenance.

Usually, these lifting systems consist of a bearing column having a rack on which a basket, equipped with a motor and pinion which is coupled to the rack of the bearing column, ascends.

To facilitate the installation of these lifting systems, modular columns have been developed. As soon as the first column module is installed, the assembly of said lifting systems proceeds with the installation of a subsequent column module which is added on top of the last column module already mounted and firmly attached to the rest of the column and/or the support structure. The installation continues, repeating this action of adding a column module above the last column module already mounted and attached, until the desired height is reached.

To overcome the problem that the lifting apparatus might continue its travel beyond the last column mounted, thus causing the uncoupling of the lifting apparatus, and the load support device connected to it, from the column itself and therefore causing it to fall to the ground, locking systems of the motor of the lifting apparatus are known, which detect the absence of the column and open a contact connected with the electric motor of the apparatus, causing it to stop.

The load support device or containing element is a cabin in the case of construction site elevators, an open basket in the case of hoists and a platform in the case of a work platform.

These lifting apparatuses are mostly used temporarily, such as on construction sites, so they can undergo frequent assembly or disassembly to reposition them elsewhere on the same site or on other sites.

The great frequency of assembly or disassembly of such lifting systems can affect overall safety, since there is a greater probability that the column will not be assembled or secured correctly, due to human error or carelessness.

Document <CIT> discloses a safety device provided with an arm maintained into pressure contact, by means of a spring device, on a mast on which a goods hoist, with a force which provokes the overturn of a mast section if it is not fixed. The arm is kept into pressure contact by means of a driver member of the thruster type.

Documents <CIT> and <CIT> describe goods hoists of the known type which have, as a container element, a basket, a cabin or a platform.

One disadvantage of the state of the art is that it is not possible to verify whether the individual modules of the bearing column are correctly mounted and attached, in particular the last module mounted, that is, the highest one.

Another disadvantage of the state of the art is that, if the last module of the column is not well attached to the other modules of the column, once the lifting apparatus is in correspondence with said module, the latter can detach from the rest of the column, causing the lifting apparatus to fall.

In this case, any object and/or person present in the cabin, in the basket or on the platform of the lifting apparatus also falls (together with the lifting apparatus itself) causing damage to the objects present in the load support device, damage to objects or people on the ground in the zones surrounding the basket, or, more seriously, traumas of varying importance or even death to the people transported at the time of the fall.

Another disadvantage of the state of the art is that it is impossible to verify the correct assembly of a module of the bearing column during the assembly or disassembly of the lifting system.

Yet another disadvantage of the state of the art is the reduced safety in the use of the lifting apparatus during assembly, disassembly, or operational use of the lifting system.

In particular, one purpose of the present invention is to provide a safety device which allows to verify the correct assembly of the bearing column.

Another purpose of the present invention is to provide a safety device which allows to verify the presence of the last module of the bearing column and, therefore, before the lifting apparatus reaches it.

Another purpose of the present invention is to provide a safety device which allows to prevent the lifting apparatus from falling.

Another purpose of the present invention is to provide a safety device which allows to determine the correct assembly of the bearing column when the lifting system is mounted.

Another purpose of the present invention is to provide a safety device that allows to increase safety in the use of a lifting apparatus during assembly, disassembly, or operating use of the lifting system.

Further purposes of the present invention are to provide a safety device, a lifting apparatus, a lifting system and a method for assembly, disassembly, and use of a lifting system which allow to overcome the disadvantages of the state of the art as described above.

In accordance with the above purposes, the embodiments described here concern a safety device comprising a support element and at least one safety element integral with the support element.

The at least one safety element comprises a sustaining element, a traction element mechanically connected to the sustaining element in such a way as to allow a movement of the traction element, and a command element configured to open an electrical safety contact when the traction element moves with respect to a predetermined position.

The safety device also comprises a driver element connected at one end thereof with the traction element and configured to exert a traction force on the traction element toward the sustaining element.

The safety device further comprises a first locking element which protrudes from an upper end of the sustaining element and which is configured to intercept an overturned module of a substantially vertical bearing column in order to contain the rotation thereof, and/or a second locking element in correspondence with a lower end of the sustaining element and configured to be disposed behind at least one pillar of said substantially vertical bearing column, said at least one pillar being proximal with respect to the position of said safety device.

In one example of the invention, the driver element is connected at its other end to the sustaining element.

In yet another example of the invention, the traction element comprises at one end thereof, distal with respect to the sustaining element, a contact protrusion configured to transmit the traction force generated by the driver element and having a sliding surface facing toward the sustaining element.

In another example of the invention, the driver element is a spring or an elastic element or a weight.

In another example of the invention, the command element is selected from a single pole switch, a limit switch, or a current diverter.

Furthermore, according to another aspect of the invention, a lifting apparatus is created which comprises a motor element equipped with at least one electric motor and a pinion driven by the electric motor and configured to be coupled to a rack; and a containing element configured to contain people and/or objects and connected to the motor element. The lifting apparatus also comprises a safety device as described above.

In one example of the invention, the containing element is a cabin, a basket or a platform.

Furthermore, another aspect of the invention provides a lifting system comprising at least one substantially vertical bearing column and comprising a plurality of modules, wherein each module comprises at least three pillars wherein at least one of the plurality of pillars comprises a rack, or the rack is attached on the column.

The modules stack perfectly in such a way that each pillar of each module is perfectly overlapping along the vertical with an associated pillar of the module below.

The lifting system comprises a lifting apparatus, wherein the pinion of the motor element couples to the rack in order to allow the movement of the movement apparatus, and wherein the sliding surface of the traction element is in contact with a pillar which is located in an intermediate position between the sliding surface and the sustaining element of the safety device, in such a way as to allow the traction element to exert a constant traction on the module.

In one example of the invention, the command element defines an electrical safety contact that allows the electrical connection between the electric motor of the motor element and an electrical power supply.

In another example of the invention, the command element is configured to open the electrical safety contact when it detects a displacement of the traction element, thus preventing the power supply of the electric motor.

In another example of the invention, the lifting system comprises a plurality of bearing columns and the lifting apparatus comprises a plurality of safety elements, wherein each safety element is associated with a respective column of the plurality of columns.

In another example of the invention, when the command element of at least one column of the plurality of columns determines a displacement of the traction element, the lifting system is configured to stop the electric power supply of all the electric motors.

In another aspect of the invention, there is provided a safety control method of a lifting system, which comprises the following steps:.

With reference to <FIG>, a lifting system <NUM> comprises a bearing column <NUM> which defines an axis A, usually the vertical axis or a substantially vertical axis. The bearing column <NUM> consists of a plurality of modules 11d the same as each other and with a polygonal section along a plane perpendicular to the axis A, wherein the polygon associated with such section comprises at least three vertices, each one corresponding to the position of a pillar 11a of the bearing column <NUM>.

The modules 11d stack perfectly, in such a way that each pillar 11a of each module 11d is perfectly overlapping and aligned along the vertical with an associated pillar 11a of the module 11d below and of the module 11d above.

The pillars 11a of each module 11d are connected two by two by means of tie rods 11b, and each module 11d comprises a rack 11c (shown in <FIG>).

The rack 11c can be positioned in correspondence with a pillar 11a or in an intermediate position between two pillars 11a.

Each module 11d is made integral with a module 11d below by means of attachment means such as screws, bolts, or suchlike located at the ends of each module in correspondence with each pillar 11a.

A plurality of stacked and integral modules 11d form the bearing column <NUM> which has a number of pillars 11a equal to the number of pillars 11a of each single module 11d.

Although the drawings show a triangular-based bearing column <NUM>, the person of skill in the art will understand that this is a non-limiting example of the invention and that what described here can be applied to bearing columns that have a polygonal base different to the triangular one.

The person of skill in the art will understand that the invention also concerns a column <NUM> consisting of only two pillars 11a connected to each other by tie rods 11b and which are then attached along a bearing wall or structure.

Ultimately, the person of skill in the art will understand that the invention concerns a bearing column <NUM> comprising at least two pillars 11a.

The lifting system <NUM> also comprises a lifting apparatus <NUM> having at least one motor element 12a which comprises a motor (not shown in the drawings) and a pinion (not shown in the drawings) which is configured to couple to the rack 11c in order to allow the movement of the lifting apparatus <NUM> along the axis A.

The lifting apparatus <NUM> also comprises a containing element 12b, for example a basket, a cabin or a platform, configured to contain and/or transport people and/or objects. The containing element <NUM> can also be defined as a load support device.

Thanks to the propulsion of the motor, usually an electric motor, and to the coupling between the pinion and the rack 11c, the lifting apparatus <NUM> can be moved along the axis A in both senses. This allows to lift or lower people and/or objects contained in the containing element 12b.

The lifting apparatus <NUM> also comprises a safety device <NUM> integral therewith. The safety device <NUM> is configured to lock the motor of the lifting apparatus <NUM> in the event that a status of incorrect assembly of a module 11d of the bearing column <NUM> is determined, in particular in the event that a module 11d is not correctly attached to the module 11d below or in the event that a module 11d is missing.

With reference to <FIG> and <FIG>, the safety device <NUM> includes a support element <NUM> configured to be attached to the lifting apparatus <NUM> and a safety element <NUM>' mounted integral therewith.

The safety element <NUM>' comprises a sustaining element <NUM> attached in a non-removable manner to the support element <NUM> and a traction element <NUM> mechanically connected to the sustaining element <NUM>. In the embodiment shown in the drawings, the traction element <NUM> is connected rotatable with respect to the sustaining element <NUM>.

The support element <NUM> and the sustaining element <NUM> can also be built as a single piece.

The support element <NUM> is configured to allow a rigid mechanical connection to the lifting apparatus <NUM> by means of attachment means, such as screws, bolts, and suchlike, not shown in the drawings, or by means of a pressure interlocking with a mating part present on the lifting apparatus <NUM>.

Optionally, the safety device <NUM> is attached to the lifting apparatus <NUM> by means of a welding between the support element <NUM> and the mating part present on the lifting apparatus <NUM>.

The safety device can be attached both to the motor element 12a and also to the containing element 12b of the lifting apparatus <NUM>.

The sustaining element <NUM> is attached to the support element <NUM> in such a way that relative movements between the sustaining element <NUM> and the support element <NUM> are not possible. In other words, the lifting apparatus <NUM> and the safety device <NUM> form a single block when the safety device <NUM> is mounted on the lifting apparatus <NUM>.

The traction element <NUM> is mechanically connected to the sustaining element <NUM> by means of a joint element <NUM> such as a hinge, a mobile joint, a through screw, a bolt and suchlike. The joint element <NUM> is configured to allow the relative movement between the traction element <NUM> and the sustaining element <NUM>.

A driver element <NUM> is mechanically connected with a first end thereof to the traction element <NUM> and with its second end to the sustaining element <NUM>. The driver element <NUM> is configured to exert a force on the traction element <NUM> directed toward the sustaining element <NUM>. In other words, the driver element <NUM> is configured to make the traction element <NUM> move toward the sustaining element <NUM>. The driver element <NUM> can be a spring, an elastic mean, an electric actuator, a pneumatic or hydraulic actuator and suchlike. The person of skill in the art will understand that the driver element <NUM> is not limited to the previous examples and that any mechanism whatsoever capable of exerting a traction on the traction element <NUM> that makes it move toward the sustaining element <NUM> can be used in the present invention.

The person of skill in the art will understand that the position of the driver element <NUM> is not limited to the position shown in <FIG>.

If no external force is applied to the traction element <NUM>, except for the force exerted by the driver element <NUM>, the traction element <NUM> moves toward the sustaining element <NUM> under the effect of the traction force of the driver element <NUM>. On the contrary, when an external force is exerted on the traction element <NUM> and when this force has the opposite sense with respect to the sense of the force generated by the driver element <NUM>, and modulus greater than it, the traction element <NUM> moves away from the sustaining element <NUM>.

A position of maximum opening corresponds to a predetermined position of the driver element <NUM> in the operating configuration. The position of maximum opening corresponds to the position of the traction element <NUM> when the safety device <NUM> is mounted on the lifting apparatus <NUM>, which is in turn mounted on a correctly mounted module 11d of a column <NUM>.

The traction element <NUM> also comprises a contact protrusion 102a, protruding from one end of the traction element <NUM> which is located in a distal position with respect to the sustaining element <NUM>. The contact protrusion 102a comprises a sliding surface 102a' (<FIG>) facing toward the sustaining element <NUM> and configured to slide along a surface, for example the surface of the pillar 11a of the bearing column <NUM> of a lifting system <NUM>.

In one example of the invention, the sliding surface 102a' is the external surface of a wheel free to rotate around its main axis, the wheel being part of the contact protrusion 102a. In the embodiment shown, the wheel comprises a peripheral groove, corresponding to the sliding surface 102a' configured to engage in a respective pillar 11a, which generally has a circular section. The person of skill in the art will understand that the invention is not limited to pillars 11a that have a circular section but that it can equally be used with pillars with a rectangular or square section.

A command element <NUM> is installed on the safety device <NUM> in contact with the traction element <NUM> or any other element integral with the traction element <NUM>. For example, in <FIG>, the command element <NUM> is located in direct contact with the traction element <NUM>, while in the example shown in <FIG> the command element <NUM> is located in contact with a connection element <NUM> integral with the traction element <NUM> and which extends in an orthogonal direction with respect to a plane on which the traction force generated by the driver element <NUM> acts.

The command element <NUM> is configured to allow the opening or closing of an electrical safety contact, that is, to prevent or allow, respectively, the passage of an electric current inside a circuit. The command element <NUM> is configured in such a way as to allow the passage of a current, that is, to close an electrical safety contact, when the traction element <NUM> is in the position of maximum opening.

The command element <NUM> is also configured in such a way as to open an electrical safety contact, that is, to prevent the passage of a current, as soon as the traction element <NUM> leaves the position of maximum opening, that is, when the traction element <NUM> moves toward the sustaining element <NUM>.

In other words, the command element <NUM> acts as a limit switch which opens a contact as soon as the position of the traction element <NUM> differs from the position of maximum opening.

The command element <NUM> can be any switch whatsoever, such as a single pole switch, a limit switch, a current diverter and suchlike. Such switches can be defined as safety switches when certified as safety components.

The person of skill in the art will understand that any other type of switch that is configured to open a contact as soon as the traction element <NUM> leaves the opening position can be used, without this compromising the scope of protection of the invention.

During use, the safety device <NUM> is mounted on the lifting apparatus <NUM>. More in detail, the safety device <NUM> is mounted on the lifting apparatus <NUM> in such a way that the contact protrusion 102a of the traction element <NUM> is located in a higher position with respect to the pinion of the motor element 12a of the lifting apparatus <NUM>. We have verified that the safety device <NUM> has greater efficiency when the traction element <NUM> exerts its force on the module 11d at a distance comprised between <NUM> and <NUM> from the support element <NUM>.

During use, the safety element <NUM> is mounted in such a way that the sliding surface 102a' is in contact with the surface of a pillar 11a of the bearing column <NUM>. In other words, when the safety device <NUM> is in use, a pillar 11a of the bearing column <NUM> is located in an intermediate position between the sliding surface 102a' and the sustaining element <NUM>, always remaining in contact with the sliding surface 102a'.

In this condition, the driver element <NUM> exerts a force on the traction element <NUM> which transfers the force received to the pillar 11a of the bearing column <NUM>.

The person of skill in the art will understand that the invention is not limited to a sliding surface 102a' which engages on a pillar 11a, but that it can comprise a sliding surface 102a' which engages with a rack 11c. In one example of the invention, the sliding surface 102a' of the traction element <NUM> is a gear (not shown in the drawings) which couples to the rack 11c in such a way as to allow the traction element <NUM> to exert a constant traction on the module 11d and therefore on the bearing column <NUM> through the rack 11c. The presence of a gear as the sliding surface 102a' allows the traction element <NUM> to not change its position of maximum opening during the movement of the lifting apparatus <NUM> along the bearing column <NUM>.

In summary, in the rest of the description we will refer to a contact between the contact surface 102a' and the pillar 11a. The person of skill in the art will understand that the same description of the invention reported below also applies when the sliding surface 102a', being a gear, acts on the rack 11c instead of on the pillar 11a.

Each module 11d of the bearing column <NUM> is attached to a module below by means of attachment means, screws, bolts and suchlike, located in correspondence with each of the at least three pillars 11a.

When the lifting apparatus <NUM> travels along the bearing column <NUM>, for example when it rises along the bearing column <NUM>, the traction element <NUM> continuously exerts a pulling force on the associated pillar 11a (position p1 of <FIG>). When the traction element <NUM> acts on the rack 11c, the traction element <NUM> continuously exerts a pulling force on the rack 11c.

At the beginning of the motion, the lifting apparatus <NUM> is located on a first module 11e, on which the traction element <NUM> exerts the traction force generated by the driver element <NUM>.

During the motion of the lifting apparatus <NUM>, there will be a situation in which the traction element <NUM> is located at a higher level with respect to an upper end of the first module 11e. In this case, the traction element <NUM> exerts a force on a second module 11f located at a higher height with respect to the first module 11e which bears the weight of the lifting apparatus <NUM> (position p2 of <FIG>). The module 11e is the module 11d directly below the second module 11f and on which the second module 11f has to be attached for a correct mounting of the bearing column <NUM>.

In this case, if the second module 11f, on which the traction element <NUM> exerts a force, is not correctly attached to the first module 11e, in correspondence with which the pinion of the motor element 12a is located, the force exerted by the traction element <NUM> causes the second module 11f to be moved in the sense of the force generated by the driver element <NUM>, that is, toward the sustaining element <NUM> (position p3 of <FIG>).

Consequently, the traction element <NUM> will move and leave the position of maximum opening, causing the drive of the command element <NUM> which, consequently, will open an electrical safety contact.

On the other hand, when the second module 11f is not mounted, that is, it is not present, the traction element <NUM> does not encounter any pillar 11a, or any rack 11c as previously discussed, which counterbalances the traction force generated by the driver element <NUM>. In in this case, the traction element <NUM> moves toward the sustaining element <NUM> leaving the position of maximum opening and causing the drive of the command element <NUM> which, consequently, will open an electrical safety contact.

The command element <NUM> is configured in such a way as to close an electrical safety contact between the motor and its power supply when the traction element <NUM> is in its position of maximum opening. Conversely, the command element <NUM> is configured in such a way as to open such electrical safety contact as soon as the traction element <NUM> leaves its position of maximum opening.

Therefore, when the electrical safety contact is open due to a movement of the traction element <NUM>, for example as soon as the traction element <NUM> leaves the position of maximum opening, the motor no longer receives power supply and it is locked, without allowing the lifting apparatus <NUM> to continue its travel.

In other words, when the second module 11f is properly attached to the first module 11e, the traction element <NUM> does not move from its position of maximum opening and the motor continues to be powered and to move the lifting apparatus <NUM> along the bearing column <NUM>.

On the contrary, when the upper module 11f is attached incorrectly, that is, loosely, or it is not attached to the lower module 11e with attachment means, or simply the second module 11f is not present, the force generated by the driver element <NUM> is not counterbalanced. This causes the traction element <NUM> to move from its position of maximum opening, dragging the upper module 11f with it, when this is present but incorrectly mounted.

In this case, the command element <NUM> opens the electrical safety contact and does not allow the motor to be powered, therefore the lifting apparatus <NUM> is immediately locked. This prevents the lifting apparatus <NUM>, in particular the motor element 12a, from loading its weight on the incorrectly attached module 11f.

The person of skill in the art will understand that the same movement of the traction element <NUM> occurs if the upper module 11f is missing. In this case, the safety device <NUM> acts as a device for verifying the presence of a module 11d above the module on which the lifting apparatus <NUM> is located.

The advantage of this solution is that if an operator forgets to attach a module 11d of the bearing column <NUM> or attaches it incorrectly, for example he does not tighten the attachment systems corresponding to the at least one pillar 11a located in a distal position with respect to the operator himself, the safety device <NUM> prevents the lifting apparatus <NUM> from traveling on the incorrectly attached module, thus preventing the possibility that the module 11d itself uncouples, causing the lifting apparatus <NUM> to fall.

Another advantage is providing a device for verifying the presence of the second module 11f mounted above the first module 11e on which the lifting apparatus <NUM> is located.

As already stated, each module of the bearing column <NUM> has a plurality of pillars 11a. At the ends of each module and in correspondence with each pillar 11a there is at least one attachment mean that allows to make the pillar 11a integral with the associated pillar of the module 11d below.

When the lifting system <NUM> is mounted and when the column <NUM> has a polygonal section, at least one pillar 11a of the plurality of pillars 11a will be in a distal position with respect to the lifting apparatus <NUM>.

When the at least one attachment mean associated with the distal pillar 11a is not attached or is not attached correctly, the effect of the traction carried out by the traction element <NUM> is to create a bending moment on the module 11d which generates a rotation of the module 11d around an axis defined by the remaining pillars 11a of the module which are attached correctly.

The bending moment is given by the vector product of the arm, being the distance between the point of application of the force by the traction element <NUM> and the upper end of the module 11d below, and of the traction force generated by the driver element <NUM>.

The bending moment has to overcome a reaction stabilizing moment generated by the weight force in order to manage to move the module 11d. It is always possible, based on considerations on the weight of the module, on the point of application of the force by the traction element <NUM>, and on the module of the force generated by the driver element <NUM>, to generate a bending moment that allows to overturn the module 11d.

When the bending moment generated by the traction force of the traction element <NUM> overcomes the reaction stabilizing moment generated by the weight force, the module 11d to which the traction force of the traction element <NUM> is applied overturns toward the lifting apparatus <NUM>.

The person of skill in the art will understand that the same principle is valid with columns that have only two pillars.

In its movement, the overturned module 11d meets the upper end of the sustaining element <NUM> and ends its motion.

Optionally, in order to prevent the overturned module 11d from tilting too much with respect to the vertical, the safety device <NUM> can comprise a first locking element <NUM> which protrudes from the upper end of the sustaining element <NUM> and which is configured to intercept the overturned module 11d in order to contain the rotation thereof.

According to another option, the safety device <NUM> comprises a second locking element <NUM> in correspondence with the lower end of the sustaining element <NUM> and configured to be disposed behind the at least one pillar 11a proximal with respect to the position of the lifting apparatus <NUM>, when the lifting apparatus <NUM> is mounted on the bearing column <NUM>.

The advantage of a safety device <NUM> comprising at least one of either the first locking element <NUM> or the second locking element <NUM> is to prevent the module 11d incorrectly attached, or not attached, to the module 11d below from overturning and falling, causing damage to people and/or objects on the ground or to the containing element 12b of the lifting apparatus <NUM>.

With reference to <FIG>, the safety device <NUM> can comprise two safety elements <NUM>' disposed at the ends of one or more connection elements <NUM>. The safety elements <NUM>' are the same as the safety element <NUM>' described in relation to <FIG> and <FIG>, to which we refer for reasons of brevity.

The two safety elements <NUM>' are configured to be mounted at the ends of the support element <NUM> that has a size comparable to the size of a front section of the bearing column <NUM>.

The two safety elements <NUM>' are mounted in a specular manner with respect to each other and are configured to act simultaneously on two pillars 11a of the bearing column <NUM> which are located in a proximal position with respect to the lifting apparatus <NUM>.

In this case, the safety device <NUM> can comprise two first locking elements <NUM>, each configured to intercept a respective pillar 11a of one module 11d when this is overturned by the traction force exerted by the traction element <NUM>. For example, each first locking element <NUM> is located substantially in front of a respective contact protrusion 102a. The safety device <NUM> can also comprise two second locking elements <NUM>, each located and configured in order to abut a respective pillar 11a. For example, each second locking element <NUM> is located below a respective contact protrusion 102a and advantageously comprises a recess <NUM>' configured to engage with a pillar 11a, increasing its stability.

As already described, the lifting apparatus <NUM> can be an elevator or a goods hoist or a platform, or any mean that allows to move a containing element 12b, such as a basket, a cabin or a platform, along the bearing column <NUM>.

According to another example of the invention, the lifting system <NUM> comprises a lifting apparatus <NUM> being a basket or a platform mounted on at least two bearing columns <NUM> located at a determinate distance from each other.

Each of the at least two bearing columns <NUM> comprises at least one rack 11c in correspondence with one of the modules 11d.

The lifting apparatus <NUM> comprises a motor element 12a associated with each bearing column <NUM> which comprises a motor and a pinion which collaborates with the rack 11c associated with the corresponding bearing column <NUM>. Furthermore, the lifting apparatus <NUM> comprises a safety device <NUM> as in any previous example associated with each bearing column <NUM>.

We refer to the previous paragraphs for the detailed description of the bearing column <NUM>, of the lifting apparatus <NUM> and of the safety device <NUM>.

With reference to <FIG>, a safety control method of a lifting system <NUM> comprises the following steps.

In a first step S100, the bearing column <NUM> comprising a plurality of modules 11d is supplied.

In a second step S110, the lifting apparatus <NUM> comprising the safety device <NUM> is mounted on a first module 11e of the bearing column <NUM>, in such a way that a proximal pillar 11a of the bearing column <NUM> is in an intermediate position between the contact protrusion 102a and the sustaining element <NUM> of the at least one safety element <NUM>' so that the at least one traction element <NUM> exerts a traction force on the column <NUM>.

Starting from when the lifting apparatus <NUM> is mounted on the first module 11e of the bearing column <NUM>, the safety device <NUM> acts on the first module 11e exerting on it a traction force generated by the driver element <NUM> and applied by the traction element <NUM>, by means of the contact protrusion 102a, on a pillar 11a. This traction force is exerted continuously on the pillar 11a and, therefore, on the bearing column <NUM>, once the lifting apparatus <NUM> is mounted on the bearing column <NUM>.

When the lifting apparatus <NUM> is mounted on the first module 11e, a pillar 11a is located in an intermediate position between the contact protrusion 102a and the sustaining element <NUM>, in such a way that the sliding surface 102a' is always in contact with the pillar 11a. The traction element <NUM> is located in the position of maximum opening, defined previously.

In a third step S120, the lifting apparatus <NUM> is moved in such a way as to make it rise on the bearing column <NUM>. During the motion, the traction element <NUM> will reach a higher level with respect to the highest end of the first module 11e.

In a fourth step S130, when the traction element <NUM> reaches a higher level with respect to the highest end of the first module 11e, the safety device <NUM> determines whether the second module 11f is present and if it moves due to the traction force exerted by the traction element <NUM>.

In a fifth step S140, the safety device <NUM> blocks the ascent of the lifting apparatus <NUM> if it is determined that the second module 11f is not present, or if it is determined that the second module 11f moves due to the traction force exerted by the traction element <NUM>.

If the second module 11f is not present, the traction element 102a moves toward the sustaining element <NUM> under the force exerted by the driver element <NUM>.

If the second module 11f is present, the traction element 102a exerts a traction force generated by the driver element <NUM> on a pillar 11a of the second module 11f.

The safety device <NUM> allows the ascent of the lifting apparatus <NUM> from the first module 11e to the second module 11f if it is determined that the second module 11f is present and, if present, if it does not move due to the traction force exerted by the traction element <NUM>.

The determination S130 of the presence and movement of the second module 11f is obtained by means of the command element <NUM> connected with the traction element <NUM>.

As already stated, the traction element <NUM> continues to exert a traction force on the bearing column <NUM> generated by the driver element <NUM>. If the module 11d of the bearing column <NUM> on which the traction element <NUM> exerts a force is correctly made integral with a module 11d below, the module 11d on which the force is exerted does not move from its position.

On the other hand, if the module 11d of the bearing column <NUM> on which the traction element <NUM> exerts a force is not correctly made integral or is not completely made integral with a module 11d below, the module 11d on which the force is exerted moves from its position. This causes the command element <NUM> to detect a displacement of the bearing column <NUM> and to open the electrical safety contact with which it is associated, causing the movement of the lifting apparatus <NUM> to stop.

The same happens when the second module 11f is not present. In this case, the traction element <NUM> moves toward the sustaining element <NUM> and the command element <NUM> detects a displacement of the traction element <NUM> and opens the electrical safety contact with which it is associated, causing the movement of the lifting apparatus <NUM> to stop.

In the case shown in <FIG>, the module 11d that moves due to the traction force is the second module 11f, and the module 11d below corresponds to the first module 11e.

As soon as the traction element <NUM> leaves the position of maximum opening, the command element <NUM> determines a displacement of the second module 11f and causes the locking of the motor element 12a, as explained in detail above.

It will be clear to the person of skill in the art that this method is applicable in each lifting system <NUM> described in relation to the previous examples.

It will also be clear to the person of skill in the art that this same method can be used with a traction element 102a that engages a rack 11c and that exerts a traction force thereon. For the description of this example of the invention, please refer to the description of the safety device <NUM>, of the lifting apparatus <NUM> and of the lifting system <NUM> previously provided.

If the lifting system <NUM> comprised a plurality of safety elements <NUM>', when at least one command element <NUM> of a safety element <NUM>' determines that there has been a displacement of the second module 11f, or it determines the absence of the second module 11f, the method provides to lock the motor of each motor element 12a of the lifting apparatus <NUM>.

In other words, each command element <NUM> manages the opening and closing of an electrical safety contact according to what described above. An actual electrical safety contact associated with the plurality of command elements <NUM> is defined by a logical AND operator of the various electrical contacts associated with each command element <NUM>. The value TRUE is associated with a closed electrical safety contact, while the value FALSE is associated with an open electrical safety contact. Therefore, the actual electrical safety contact associated with the plurality of command elements <NUM> is closed if and only if each electrical safety contact associated with each command element <NUM> is closed. Otherwise, when at least one electrical safety contact is open, the effective electrical safety contact associated with the plurality of command elements <NUM> is open.

Stated again in other words, if each command element <NUM> allows the passage of a current through an electrical safety contact, the command elements <NUM> of the plurality of command elements are connected in series with each other so as to implement the logic described above.

The fact that the lifting apparatus <NUM> is locked when at least one command element <NUM> determines that the second module 11f has moved or is not present, provides additional safety to the lifting system <NUM>.

Claim 1:
Safety device (<NUM>) for a lifting apparatus, the safety device comprising a support element (<NUM>) and at least one safety element (<NUM>') integral with the support element (<NUM>), the at least one safety element (<NUM>') comprising a sustaining element (<NUM>), a traction element (<NUM>) mechanically connected to the sustaining element (<NUM>) in such a way as to allow a movement of the traction element (<NUM>), and a command element (<NUM>) configured to open an electrical safety contact when the traction element (<NUM>) moves with respect to a predetermined position, the safety device comprises a driver element (<NUM>) connected at one end thereof with the traction element (<NUM>) and configured to exert a traction force on the traction element (<NUM>) directed toward the sustaining element (<NUM>),
characterized in that it comprises a first locking element (<NUM>) which protrudes from an upper end of the sustaining element (<NUM>) and which is configured to intercept an overturned module (11d) of a substantially vertical bearing column (<NUM>) in order to contain the rotation thereof, and/or a second locking element (<NUM>) in correspondence with a lower end of the sustaining element (<NUM>) and configured to be disposed behind at least one pillar (11a) of said substantially vertical bearing column (<NUM>), said at least one pillar (11a) being proximal with respect to the position of said safety device (<NUM>).