Patent Application
20050200069
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This invention refers to an apparatus including at least one sucker, with a vacuum obtained by means of the Venturi effect or by means of a vacuum pump, with an auto-selection function for handling material of the type in sheets or objects that lend themselves to being handled with this system.
The invention finds particular application where the vacuum is used non-exclusively in the metal plate moving sectors.
In the field of industrial automations, for example, installations working <<unmanned>> or “lights off”, namely without human presence, the invention assumes particular interest.
One of the characteristics that distinguishes said installations, is the fact that each installation is prepared during day hours for functioning without human presence during nocturnal hours.
A typical case is illustrated by the installations in which automatic systems are provided for loading, on the construction line, and unloading of materials to be submitted to processing, such as metal sheets, plastic material plates, ceramic and glass, with the aim of allowing processing to be carried out continuously without the need to intervene at the end of every operative cycle. Said systems, for example, are required in sheet cutting installations, those employing laser or plasma techniques, oxygen cutting, water techniques and also others.
Generally, therefore, it is possible to consider that this concerns installations subdivided into at least two working areas, respectively an upstream unit, including the group loader-feeder of the material in sheets, an intermediate station, for instance made up of the cutting apparatus, and a possible downstream adjacent unit including a stacker-ejector of the sheet processed in this way.
With respect to these installations, certain drawbacks have been observed by operators in this sector, above all with reference to the most common grill or bench material loading systems in the intermediate station.
Among the most well-know systems, proposed for loading and unloading the sheeting, for example using a cutting apparatus grill or a bench for a folding press, it is possible to cite substantially five techniques.
The first of the four, the primary technique is known for manual removal of pieces cut from a grill or bench with the subsequent loading of the new sheet, by means of an overhead crane, fork truck, purchase block or sucker frame mounted on a fixed oscillating arm.
A second solution consists in providing two grills or benches, operating on the cutting or processing installation, in such a way as to be operated alternatively on a grill for loading and unloading, while the other is functioning. A third solution, for sheet cutting installations, is intended to optimize the system which in the previous point provided a carousel with a certain number of grills, collected in a vertical warehouse.
A fourth solution, suitable for interacting with one of the systems described previously with respect to the unloading of the grill, provides a vertical warehouse upstream of the cutting unit, with more shelves, where the sheets to be processed are pre-arranged, in such a way that, according to the program, an extractor or handler with suckers can pick up and transfer the material on the grill of the intermediate unit so it can be processed.
Prior Art
Therefore, suckers are known the in the field of assistance for machine tools and in other sectors, which, supported by conventional systems, are made to adhere the peripheral border of the circular flange to the flat surface of the underlying material to be handled. Once placed in contact, a temporary depression is produced, substantially, which causes the material to remain in contact with said suckers. In this way the suckers, raising themselves from the support base of the material, will determine the subsequent transfer of the material to an adjacent station. Once placed in the release position, a device provides the re-balancing of the pressure on the interior of the cups of the suckers, allowing the detachment of the material. It is therefore evident given that said suckers are connected to systems that allow depression generation and re-balancing of the sucker once certain conditions have been reached. More particularly, said devices utilize the Venturi effect or in some cases a common vacuum pump.
Therefore, for example in U.S. Pat. No. 5,979,889 (Klopfenstein), a practical application of the Venturi effect for generating a depression in the sucker cup is described. In detail, the sucker is mounted with the tubular connector along a main rod that is channelled to intersect it on the bias. A second connector is coaxial to the main channelled rod and develops until passing beyond the interconnection point with the tubular pin. In this way, by introducing a fluid through the second connector, the air present in the cup in contact with the material is sucked again, so that the sucker remains in very close contact or adhered to the surface of the material to be handled.
Also U.S. Pat. No. 5,928,537 (Fortune) describes a system that uses the Venturi effect to generate a vacuum on the interior of a sucker. In more detail, a tool for lifting small portions of materials is proposed, which is provided on one side with a sucker and is connected on the other side to a vacuum generator. Said vacuum generator is connected on one side to a first ON/OFF valve that allows the emission of compressed air and on the other side, downstream of the circuit, to a second valve that connects with the exterior. Operating with the first valve in open position, the compressed airflow crosses the vacuum generator that is in contact by means of a connector with the tool provided with a sucker. The compressed airflow finds a vent in a downstream position set apart with respect to the tool's connector and continues through the second valve in open position. In this way, the necessary re-suction is produced along the tool's connector, so that the sucker remains in the position of being adhered to the material. Operating inversely, thus closing the second valve, which is downstream of the circuit, the compressed airflow passes across the tool's connector and therefore re-balances the pressure on the interior of the cup obtaining the detachment of the material.
State of the Art Most Similar to the Invention
U.S. Pat. No. 4,750,768 (Kumar), describes an adhering device. This substantially concerns a pneumatic vacuum generator that uses an amp fluid sensor that senses the presence of an object when said object is in contact with the sucker cup. This circumstance activates the main Venturi effect vacuum generator that provides for forming the vacuum necessary that makes it possible for the object to be lifted. An external release signal determines the arrest of the vacuum to release the object. The energy for the vacuum, in this case, is to be generated only when the object is lifted, in such a way as to suppress energy consumption and noise. Furthermore, it is possible to adjust the level of force necessary for lifting. The fluid logic circuit, automatically blocks the vacuum in the sucker, while the supply to the main Venturi is placed in the OFF position after a pre-established period of time.
U.S. Pat. No. 5,795,001 (Burke) describes a device for manipulating articles. The small hand contains a sucker that cooperates with a circuit that includes an electric motor coupled to a vacuum pump. An electronic circuit allows the operator to control directly the application of vacuum to the sucker. Furthermore, an electronic circuit detects the prolonged vacuum between the sucker and the object to be handled and if this reaches a predetermined low level, the electronic circuit informs the operator of the condition and automatically re-starts the motor of the vacuum pump until the depression level is re-established. An alternative solution to this invention provides for a Venturi effect vacuum generator that can substitute directly the module that includes the vacuum pump.
In conclusion it is correct to affirm that at present it is known that for the formation of the vacuum in said suckers, a Venturi for each sucker or a Venturi for several suckers is applied, and if a depression greater than that which can be generated by a Venturi was necessary, it is possible to resort to a vacuum pump that, also in this case, can be applied to one or several suckers.
Drawbacks
In terms of the systems described with the Venturi effect, these present an economical advantage and are simple to apply. For example, in the case of the use of several suckers and one Venturi for each of these, it is guaranteed that if one or several suckers does not completely adhere to the object, the depression in the other suckers is maintained, thus ensuring the lifting or transportation of the piece. In this case it is evident that the suckers that are not able to create the vacuum continue to be supplied thus giving rise to the wastage of compressed air. To compensate for the air loss problem, manual taps can be applied that block the Venturi supply of the sucker to be excluded. However, it is evident that this solution appears inconvenient since manual intervention is required. From a practical point of view, this circumstance involves the stoppage of the installation causing increased down times, in one case, it can require processing on flat material pieces that often present different dimensions or are not perfectly aligned and coplanar.
Others systems, to avoid the air loss problem and to manage the valves manually, provide the application of electro-valves. These systems involve the use of management software, of electric wiring or, in the more economic version, a series of switches. From a practical point of view, the proposal causes considerable complexity in the installations with the relative implementation and maintenance costs. However, to this can be added the fact that the proper positioning of the piece to be lifted is necessary in order to avoid the useless supply to the suckers that are not involved.
In the case in which, unlike the Venturi system, it is possible to opt for an installation with a vacuum pump, or with a Venturi for the entire installation, it is necessary to define from the start of processing the suckers that activate the adhering function and those that do not. In this hypothesis, in the event that a good adherence is not provided or the sucker detaches, it would cause the depression to decline in the entire installation, thus provoking the detachment of the object from the other suckers (and eventually the stoppage of the installation).
Other systems, not mentioned previously include a relief valve where given the possible unsuccessful adherence of the object, the aspirated airflow will close the passage thus eliminating the vacuum supply. It is the opinion of the applicant that this system is not reliable, since it requires an ample aspiration flow in order for the device to in turn be able to stop the it. In a second system a small hole would always remain, through which air from the exterior continues to be sucked, thus it is not airtight.
Here there is the need for the companies to determine alternative and more effective systems not including those described previously.
One aim of this invention is also to avoid the above-mentioned drawbacks.
This and other aims are reached with this invention according to the characteristics as in the included claims, solving the arising problems, by means of an apparatus for handling material of the type in sheets or portions of flat sheets, including at least one device with an autoselection function for the lifting-release of the material, of the type with a vacuum that is obtained between the sucker and the material, by vacuum forming means through the Venturi effect or by means of a vacuum pump; this apparatus is made up of a multi-way pneumatic supply circuit of an auto-selection and auto-relief valve that includes principal pneumatic commutators, said commutators being interconnected to a third commutator that is interposed between the vacuum forming means and the auto-selection valve that supplies the sucker.
Aims of the Invention
The considerable creative contribution, verified in the proposal now described, constitutes an immediate technical progress in order to obtain different advantages.
First of all, one aim consists in conferring additional safety to the system described. The principle is based substantially on the autorelief of the formation of the vacuum created in the sucker, so that in a series of suckers those that are not adhered are excluded automatically. For example, in the event that in an installation a sucker is positioned close to the edge of the piece to be raised (ref.
A further aim consists in considering a notable saving of energy, both because the suckers not involved in the lifting exclude themselves automatically as well as because air consumption is suppressed since the supply is not required until the sucker is maintained within the values of the established depression.
These advantages have the quite relevant value of producing apparatus with a good technological, multi-functional and extremely reliable content, even if submitted to particular working loads.
Others advantages will appear from the following specific description of some preferred embodiments, with the aid of the enclosed schematic drawings, whose implementation details are not to be considered limitative, but only illustrative.
With reference also to the Figures, it is observed that in an installation for handling/lifting of flat material, for example, in sheets or pieces of sheet M, an apparatus S1, S2 is provided that includes at least one sucker 1 on the interior of which, when adhered in correspondence to the material M, is to form the vacuum.
More particularly, the apparatus S1, S2 can be divided into three blocks, respectively A, B and B1 to which at least one sucker is connected I. The block A is made up of a pneumatic installation for supplying the blocks B-B1, which are made up respectively of an auto-selector valve that cooperates with means to generate the vacuum F1, F2. In this case, said means for generating the vacuum can include a solution with Venturi effect F1 or a vacuum pump F2.
The block A, is essentially made up of:
In terms of the second and third block B-B1, that includes the auto-selection valve, it is substantially made up of:
As a rule, while the block A serves to supply one or several suckers 1, the block B-B1 can be applied to every sucker or group of suckers according to the needs of the installation.
Apparatus Activation Phase
In
In terms of airflow originating from the electro-valve 1 entering into the block B-B1 through the circuit P, it is observed that this will supply the Venturi F1 and open the relief valve G to activate a depression in the circuit L and therefore maintain the piston D1 in auto-relief position (0.1) maintaining this position only if the sucker I is well positioned.
The block B-B1 forms part of a third pneumatic commutator E that is connected to said circuit P1 and P. In this position said commutator E does not move, as it requires higher pressure since it is provided with a more rigid spring E2.
Consequently, the airflow introduced by the electro-valve 1, along the circuit P passes first across the pneumatic commutator C and D, then across the commutator E to supply the Venturi effect vacuum generator F1. The Venturi F1 forms the vacuum that will thus lift the sphere of the relief valve G in this way supplying the circuit L with a depression that will simultaneously supply the sucker I for the movement of the material M and the piloting of the circuit L. The depression of the piloting on circuit L, passing through the perforations D3 of the shaft of the piston D1, forms an eddy in the upper chamber of the commutator D maintaining the piston D1 in position 0.1, forming an auto-relief circuit. The depression created in the circuit L involves one or more suckers I. The suckers, adhered to the piece to be moved, even in the event of a small intake of air from the exterior, cause a rapid depression increase in the circuit L until tripping the auto-relief phase of the system (piston D1).
Apparatus Autorelief Phase
(Ref.
Apparatus Stand-By Economy Phase
(Ref.
Intervention Phase in Case of Depression Loss
(Ref.
Reactivated Depression Phase
(Ref.
Detachment Phase of Sucker I From Material M
(Ref.
The apparatus described above can be utilized even without vacuum generator means of the type with Venturi effect F1. In this case, instead of supplying the apparatus through the line P with air pressure, it can be supplied directly by a vacuum pump (ref.
