ES2394334B1 - EMERGENCY DEVICE FOR SAFE LIFTING OF LOADS - Google Patents

Abstract

The invention relates to an emergency device for safe descent of loads, where the device in question is configured as an electrical system connected to the conventional electrical installation of the crane and comprising: at least one power module (1) connected to a direct current bus (2), so that they maintain the voltage of said bus; drive inverters (3) of the lifting (4?) and transfer (4) motors of the crane, which hang from said direct current bus (2), taking the necessary energy from it or returning the one returned by the motors during the maneuver of descent in the elevations, or braking in the horizontal movements; at least one starter exciter (6) to power the control components, when there is a power failure; and, at least, a mechanical accumulator (8), leaving it predisposed to start it again.

Description

Emergency device for safe descent of loads

OBJECT OF THE INVENTION

The invention, as expressed in the statement of the present specification, refers to an emergency device for safe descent of loads, contributing to the function to which advantages and novelty characteristics are destined, which will be described in detail below and which suppose a remarkable improvement in the current state of the art.

More particularly, the object of the invention focuses on a device that is configured as an electrical system, preferably applicable in cranes but without its application being discarded to any other type of similar machinery, whose purpose is to provide a starting system of emergency and safe descent of loads, in front of a loss of power when the crane bridge is with a suspended load.

FIELD OF APPLICATION OF THE INVENTION

The field of application of the present invention is part of the technical sector of the industry dedicated to the manufacture of cranes and the like, focusing particularly on the field of electrical systems and installations that make them work.

BACKGROUND OF THE INVENTION

Lifting systems have passive safety elements that intervene with their discouragement and maintain the load they handle in a safe situation.

The retention brakes, once they lack power, must be able to maintain the nominal load of the crane suspended for an indefinite period of time.

On certain occasions, due to the characteristics of the cargo handled, it must be possible to have such means that allow its controlled descent to the ground.

There are different techniques known for this purpose, however, at least on the part of the applicant, there is no knowledge of the existence of any other device, system or installation that presents technical, structural and constitutive characteristics similar to those presented here. it is recommended, as claimed.

In this regard, it should be noted that there is evidence of any attempt using UPSs with accumulators based on chemical electrolytes not allowed in certain facilities.

There are other solutions, formerly used that consisted of the use of dynamic braking resistors in DC motors with independent excitation that took advantage of the remaining magnetism of the inductor poles.

In these cases, however, the opening of the brakes was done manually and no active safety element was lacking. Furthermore, with such systems, only the movement of lowering of loads is possible.

The disuse of DC motors has caused the loss of use of the emergency descent control indicated in the previous paragraph.

EXPLANATION OF THE INVENTION

Thus, the emergency device for safe descent of loads that the present invention proposes is configured as a remarkable novelty within its field of application, since unlike other systems, it is capable of operating with all the necessary supervision and safety elements to ensure, at all times, the descent of the load.

The systems related to security that are considered necessary are kept operative, such as: emergency shutdowns, over speed protection and / or any other element or device that can be considered in each specific application.

The opening of the brakes is done automatically once all the necessary conditions coincide. In the event of any disturbance, the automatic closing of the same occurs, leaving the load retained again and in a safe and stable condition until the normalization of the disturbance or breakdown occurred.

Another of the particularities presented by the device of the invention is that the initial energization of the control and safety systems is carried out by recovering potential energy of mechanical origin accumulated previously. This energy can have different origins, depending on the needs of each application.

The use of accumulated energy of mechanical origin avoids the use of other chemical-type accumulator devices, such as uninterruptible power supplies, condenser batteries, etc., which may introduce undesirable chemical elements and gases into the atmosphere.

The energy returned by the system during the descent of the load is not possible to return it to the network, because it lacks it, however, said energy is used for its use in:

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The new accumulation of mechanical energy and to be able to have a sufficient amount to restart the process in case it should stop for whatever reasons.

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The feeding of the horizontal movements, in the case that is required, to be able to move the load horizontally to a vertical one that allows its safe support.

The rest of the remaining energy is dissipated in the form of heat through a dynamic braking resistor system.

Thus, the operation of the device is essentially the following:

The device monitors the presence of correct voltage in the power supply at all times.

If this is correct, the crane operates normally and, at the same time, keeps the emergency device for safe descent of loads loaded and prepared for use.

The loss of power in the crane causes the immediate stop of all its movements due to de-energization and fall of all its brakes.

In this case, the emergency device for safe descent of loads is ready for intervention and the following operating sequence is established:

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It occurs after a manual boot order. This is the only manual intervention to be performed, since the rest of the sequences are performed automatically.

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It includes the power of the control equipment of the lifting motors and all the safety elements that have to be available to ensure the correct descent of the load.

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The completion of the connection of the control system and protection elements, together with the necessary conditions for the start of the descent, among others the check of the power to the motors and their magnetization to guarantee the response in the pair, give the order of opening of the brakes so that the descent of the load begins.

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The descent of any load causes the return of the accumulated potential energy due to the loss of height of the same.

This return is used to replenish the energy taken from the emergency device so that it is available and can be restarted in the event that the movement of load descent had to be stopped before reaching the ground.

While the load descends, it is possible to take advantage of the rest of the energy that returns to the system to make horizontal displacements and move the load to the vertical of a safe area so that it can be supported.

Obviously this possibility is conditioned by the weight of the load to descend and the height at which it is located.

Once the load is on the ground, the device stops and de-energizes completely at the end of the return of energy of the descent of the load.

When this occurs, the load will be accessible for the completion of the tasks required.

It should be noted that any disturbance, failure or breakdown causes the immediate closing of the brakes.

The return of the energy taken from the initiating event predisposes the system to restart the movement safely as many times as necessary.

The described device has very important advantages in handling applications of high responsibility loads, in which there is a certain time for handling and where the environmental conditions are particular.

Among these advantages, it is worth noting, as a summary, the following:

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Total absence of chemical elements such as electrolytes, acids, gases, etc.

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 Existence and action, if necessary, of automatic safety elements.

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Control over the opening of the brakes, since it is not possible to open if a minimum of conditions are not established.

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Elimination of the “human factor” on the brake opening control, although it is possible to give an immediate stop order by acting on any emergency stop button.

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Possibility of restart in case you need to stop the movement.

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Possibility of acting on horizontal movements to move the load towards a new vertical.

Given the foregoing, it is found that the described emergency device for safe descent of loads represents an innovation of unknown characteristics until now for the purpose it is intended, reasons that together with its practical utility, provide it with sufficient grounds to obtain the exclusivity privilege requested.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made of the invention, and to help a better understanding of the characteristics that distinguish it, the present descriptive report is attached, as an integral part thereof, of a set of drawings, in which with Illustrative and non-limiting nature has represented the following:

Figures 1 to 8. - Sample shows a single-line electrical diagram, corresponding an example of embodiment of the emergency device for safe descent of loads object of the invention, in their respective phases of operation, having represented in each of said diagrams the sections that are in operation with a thicker line to facilitate understanding. In addition, the arrows represented on said thick strokes indicate the direction of the system's energy.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the aforementioned figures, and according to the numbering adopted, it can be seen how the device in question is configured as an electrical system connected to the conventional electrical installation of the crane and comprising:

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at least one power module (1) connected to a direct current bus (2), so that they maintain the voltage of said bus;

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drive inverters (3) of the lifting (4 ') and transfer (4) motors of the crane, which hang from said direct current bus (2), taking the necessary energy from it or returning the one returned by the motors during the maneuver of descent in the elevations, or braking in the horizontal movements;

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at least one starter exciter (6) to power the control components, when there is a power failure;

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and, at least, a mechanical accumulator (8), leaving it predisposed to start it again.

In addition, it includes, at least, a support exciter (6 ’), if deemed necessary, to magnetize the motor, or lifting motors (4’) and then open brakes (7).

And, at least, a dynamic braking resistor (5) to fire the energy returned to the system in the form of heat.

In summary, then, it is about taking advantage of the particularities of the power modules, inverters and modules with dynamic braking resistance of conventional lifting devices to add the exciters with their respective power modules that hang “downstream”.

In accordance with the logic diagram of the sequence of operation of the device of the invention, reflected in Figures 1 to 8, the phases comprising said operation are the following:

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Phase 0 (figure 1): During normal crane operation, the system is powered by at least one power module (1), can be unique, or have several working simultaneously and can also be only food or feed and return to the network.

This module or power modules (1) maintain the voltage of the direct current bus (2).

The drive inverters (3) of the motors (4, 4 ') hang from this DC bus (2), taking the necessary energy from it or returning the one returned by the motors during the descent maneuver in the elevations, or braking in horizontal movements.

The energy returned to the system can be returned to the network, if the power module (1) allows it, dissipated in the form of heat through a dynamic braking resistor (5) arranged at the end of the bus.

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Phase 1 (figure 2): After a failure in the power supply (S) of the crane with a suspended load, the accumulated mechanical energy is recovered through the starter exciter (6) to power the control components.

It may be necessary to have more than one exciter.

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Phase 2 (figure 3): A more energetic recovery, with a support exciter (6 ’), serves to magnetize the motor,

or lifting motors (4 ’) and then open brakes (7). A second exciter may be necessary at this stage depending on the characteristics of the motors and brakes.

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Phase 3 (figure 4): Once the descent begins, the lifting motors (4 ’) recover the energy returned by the system.

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Phase 4 (Figure 5): When the level of energy returned is sufficient, the system is recharged through a mechanical accumulator (8), leaving it predisposed to start it again.

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Phase 5 (figure 6): Taking advantage of the energy returned it is also possible to perform horizontal movements, since said energy can be delivered to the carriage and bridge transfer motors (4).

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Phase 6 (figure 7): The energy surplus is transformed into heat by means of the dynamic braking resistor (5).

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Phase 7 (figure 8): The perching of the load on the ground ends the cycle.

Describing sufficiently the nature of the present invention, as well as the way of putting it into practice, it is not considered necessary to make its explanation more extensive so that any person skilled in the art understands its scope and the advantages that derive from it, stating that, within its essentiality, it may be carried out in other embodiments that differ in detail from that indicated by way of example, and to which it will also achieve the protection that is sought provided that it does not alter, change or modify its fundamental principle .

Claims (3)

1.-EMERGENCY DEVICE FOR SAFE LIFTING OF LOADS, applicable to cranes or similar machinery, as an emergency start and descent system in case of power loss, which being of the 5 type that is usually configured as an electrical system for this type of applications using at least one power module (1) connected to a direct current bus (2); drive inverters (3) of the lifting (4 ’) and transfer (4) motors; at least one dynamic braking resistor (5) is characterized in that it also incorporates at least one starter exciter (6) with its corresponding power module that hangs downstream, to power the control components, when there is a fault power supply; 10 and at least one mechanical accumulator (8), leaving it predisposed to start it again. 2. EMERGENCY DEVICE FOR SAFE LIFTING OF LOADS, according to claim 1, characterized in that it includes at least one support exciter (6 ') to magnetize the motor, or lifting motors (4') and subsequently open brakes (7).  SPANISH OFFICE OF THE PATENTS AND BRAND Application no .: 201231061  SPAIN Date of submission of the application: 06.07.2012 Priority Date: REPORT ON THE STATE OF THE TECHNIQUE   51 Int. Cl.: See Additional Sheet RELEVANT DOCUMENTS

Category

56 Documents cited Claims Affected

X

WO 2006016002 A1 (KONE CORP; JAHKONEN PEKKA) 16.02.2006, page 8, line 21 - page 12, line 28; Figure 1. 1.2

TO

US 6094024 A (WESTLAKE) 25.07.2000, column 2, line 66 - column 6, line 6; figures. 1.2

TO

EP 0471348 A1 (OTIS ELEVATOR CO) 19.02.1992, column 4, line 33-column 6, line 55; figures. 1.2

TO

US 2007084673 A1 (THYSSEN ELEVATOR CAPITAL CORP) 04/19/2007, the whole document. 1.2

Category of the documents cited X: of particular relevance Y: of particular relevance combined with other / s of the same category A: reflects the state of the art O: refers to unwritten disclosure P: published between the priority date and the date of priority submission of the application E: previous document, but published after the date of submission of the application

This report has been prepared • for all claims • for claims no:

Date of completion of the report 18.12.2012

Examiner F. J. Riesco Ruiz Page 1/4

 REPORT OF THE STATE OF THE TECHNIQUE Application number: 201231061 CLASSIFICATION OBJECT OF THE APPLICATION B66B5 / 02 (2006.01) B66C15 / 00 (2006.01) B66D5 / 02 (2006.01) Minimum documentation sought (classification system followed by classification symbols) B66B, B66C, B66D Electronic databases consulted during the search (name of the database and, if possible, terms of search used) INVENTIONS, EPODOC, WPI State of the Art Report Page 2/4  WRITTEN OPINION  Application number: 201231061 Date of Completion of Written Opinion: 18.12.2012 Statement

Novelty (Art. 6.1 LP 11/1986)

Claims 1.2 YES

Claims

NO

Inventive activity (Art. 8.1 LP11 / 1986)

Claims YES

Claims

1.2 NO

The application is considered to comply with the industrial application requirement. This requirement was evaluated during the formal and technical examination phase of the application (Article 31.2 Law 11/1986).  Opinion Base.- This opinion has been made on the basis of the patent application as published. State of the Art Report Page 3/4  WRITTEN OPINION  Application number: 201231061  1. Documents considered.- The documents belonging to the state of the art taken into consideration for the realization of this opinion are listed below.

Document

Publication or Identification Number publication date

D01

WO 2006016002 A1 (KONE CORP; JAHKONEN PEKKA) 02/16/2006

 2. Statement motivated according to articles 29.6 and 29.7 of the Regulations for the execution of Law 11/1986, of March 20, on Patents on novelty and inventive activity; quotes and explanations in support of this statement The object of the invention is an emergency device for safe descent of loads, applicable to cranes or similar machinery as an emergency starting and lowering system in case of loss of power. It is an electrical system that uses a power module connected to a direct current bus, drive inverters for lifting and moving motors and a braking resistor. It also incorporates a start exciter, with its corresponding downstream power module, to power the control components when there is a power failure; and a mechanical accumulator. Document D1 discloses an emergency device for safe descent of loads, applicable to elevators as an emergency starting system and descent in case of loss of power. It is an electrical system that uses a power module connected to a DC bus, drive inverters of the lifting motor and a braking system that allows energy recovery. It also incorporates a starter switch (16) which allows the control components and the motor to be powered, when there is a power failure, with the energy accumulated in a supercapacitor during normal operation (see page 8, line 21 page 12, line 28; figure 1). The fact that the braking system specifically comprises a dynamic braking resistor is common knowledge in the state of the art. Therefore, the invention defined in claims 1.2 does not differ from the known technique described in document D1 in any essential way, being considered obvious to one skilled in the art. Accordingly, the invention according to claims 1.2 is not considered to involve inventive activity based on what is disclosed in document D1 (Art. 8 LP). State of the Art Report Page 4/4