Safety switches with touch panel for monitoring access to machines or industrial plants

Abstract

A safety switch for monitoring access to a machine or industrial plant comprises a switching device (5, 105) having a casing (6, 106) accommodating electrical and / or electronic control means adapted to be connected to one or more control and / or signaling circuits for controlling said machine or plant, an operating device (2, 102) adapted to be coupled to a movable part (M) of said access (A) and interacting with said switching means when said access (A) is opened / closed for opening / closing one or more of said circuits, and means for detecting the opening of said access (A), said switch means associated with said operating device (2,102) for transmitting a stop command for said machine or plant upon said detection or a request for opening said access (A) and drive means (9,109) for transmitting activation / deactivation and / or signaling controls; and at least one touch monitor (10,110) associated with said casing (6,106) and equipped with one or more virtual controllers, and at least one microprocessor suitable for associating said one or more virtual controllers with control and / or signaling functions.

Description

[Technical field]

[0001] The invention finds application in the field of industrial electrical equipment and in particular relates to a safety switch associated with a touch panel adapted for application to a barrier or protective panel for monitoring access to a machine or industrial plant. [Background technology]

[0002] As is known, access to a machine or industrial plant requires constant surveillance through countermeasures which prevent spontaneous or accidental intrusion of the operating boundary by an operator.

[0003] For this purpose, access such as barriers, boundaries and protective panels are generally equipped with one or more safety devices connected to the power supply circuits and possibly auxiliary service circuits of the machine or plant, constantly reporting both the operational status of the machine or plant and any operational abnormalities that may affect any part of the plant, in order to allow access within the boundaries only after the machine or plant or any hazardous part thereof has been stopped.

[0004] The degree of security of these devices must be higher the greater the risk that an operator would face if he were to enter the perimeter while the machine or plant is still operational.

[0005] Typically, the safety device comprises a switching device designed to be coupled to a fixed part of the barrier, which accommodates various circuits suitable to be connected to the power supply and / or service circuits of the machine or plant in order to determine opening / closing or to send signals in response to an external command.

[0006] An operating device is instead fixed to the moving part and has the role of generating various signals indicating the closed access status and of interacting with the switching device in order to prevent the opening of the access if predefined safety conditions for a particular machine or system are not met.

[0007] In most cases, the switching devices are also equipped with mechanical, electrical, or electromechanical means designed to prevent access being opened under unsafe conditions or by unauthorized personnel.

[0008] A particular type of access control device is a safety handle, a device which not only allows the opening and closing of the access, but also allows the plant or only parts of it to be stopped when the access is opened or simply unlocked.

[0009] An example of a safety handle is disclosed in US2005108945, which is equipped with a magnetic sensor means for detecting the opening of access and controlling the associated opening of the power circuit and the associated shutdown of the plant.

[0010] Another example of a safety handle is disclosed in DE 102009039591, which handle is associated with operating means suitable for interaction with an operating device associated with the fixed part of the access.

[0011] Generally, these handles comprise a main body formed by an articulating bracket fixed to the frame of the mobile part of the access, and a further body or casing fixed to said bracket and also performing the function of the handle.

[0012] For example, in EP Patent No. 2 264 353 in the name of the applicant, the handle comprises a connecting bracket fixed to the movable part of the access, on which the handle, integral with the key actuator, slides and interacts with a switching means associated with a fixed part of the access.

[0013] The fixing of the handle of the main body to the movable part of the access is carried out by universal fixing elements such as screws, pins or snap means, which, depending on the form of the handle, can be inserted at the front and rear or both at the left and right of the body.

[0014] A further example of such a handle is disclosed in EP 2 112 674, always in the name of the Applicant.

[0015] Generally, known safety handles are designed to interact with a switching device attached to the fixed frame of the access to be monitored and interact with the above-mentioned locking / unlocking means such that the pin is locked, not allowing the access to be opened under conditions in which the machine or system is unsafe.

[0016] Generally, regardless of the particular configuration of the operating device, e.g. whether or not it is provided with a handle or gripping element, the switching device may be provided with or at least associated with a pushbutton panel having one or more controllers, such as pushbuttons and / or selectors, which are used to lock the operating device and are suitable for intervening in the power supply circuit and / or additional auxiliary circuits following activation by an operator, based on the particular requirements for the plant to be controlled.

[0017] Typically, these control pushbuttons are disconnected from the switches to which they are wired during installation.

[0018] In a further solution, the push button panel is either integrated into the body of the switching device or designed to be applied by removing an access cover and wiring a controller to the internal control circuitry.

[0019] As a consequence, however, similar solutions limit the number of controllers that can be associated with the same switch, as well as the possibilities for customization of the device, especially due to the limited space available.

[0020] Furthermore, the need to connect each individual controller to the device's internal circuitry makes the assembly process laborious and complicated, with a corresponding increase in overall cost. Summary of the Invention

[0021] The object of the present invention is to overcome the above-mentioned drawbacks by providing a safety device with a touch panel, adapted for application in access for the control of industrial machines or plants, characterized by high efficiency and relative cost-effectiveness.

[0022] A particular object is to provide a safety switch with a touch panel that is designed to operate on one or more control and / or service circuits and that can be associated in a structurally simple manner with a large number of commands designed to verify the operation of the system.

[0023] Yet another object is to provide a safety switch with a touch panel that offers the possibility of customizing the commands associated therewith.

[0024] Yet another object is to provide a safety switch with a touch panel which is highly secure against opening of access under unsafe conditions or by unauthorized persons.

[0025] Yet another object is to provide a safety switch with a touch panel that is highly secure against any attempt at disassembly under closed access conditions and potentially provides evidence of tampering or attempted disassembly.

[0026] These objects, as well as others which will be more clearly expressed hereinafter, are achieved by a safety device with a touch panel according to claim 1, comprising a switching device having a casing connected to the fixed part to be monitored and housing switching means for controlling one or more control and / or service circuits of the plant suitable to be coupled thereto and electrical and / or electronic control means suitable to be connected to one or more control and / or signalling circuits of the machine or plant, an operating device connected to a movable part of the access and adapted to interact with said switching means when the access is opened / closed for opening / closing one or more of said circuits, means for detecting the opening of the access associated with said switching device and said operating device, means for sending a stop command to the control means for stopping the machine or plant following a detection or a request to open the access, and drive means connected to said control means for sending activation / deactivation and / or signalling commands.

[0027] The drive means are associated with said casing and comprise at least one touch monitor with one or more virtual controllers and a process unit, e.g. a microprocessor adapted to associate each of said virtual controllers and / or signalling functions and to associate these by means of said control means with one of the circuits of said machine or plant.

[0028] In this way, it would be possible to associate a large number of different commands with the switches in a structurally simple manner, i.e., to associate specific functions with each zone of the monitor in a programmable manner without the need for a physical controller, thereby allowing the monitor's functionality to be customized according to the user's requirements.

[0029] By the terms "touch panel" and "touch monitor", we intend to denote a screen that is sensitive to pressure or simple touch applied by a user using both a portion of the body and / or multiple portions of the body or other touch devices, and that also functions as an input device.

[0030] Advantageous embodiments of the invention are obtained according to the dependent claims. [Brief description of the drawings]

[0031] Further features and advantages of the present invention will become more apparent in the light of the detailed description of preferred but non-exclusive embodiments of a safety switch according to the invention, given as non-limiting examples with the aid of the accompanying diagrams and figures.

[0032] [Figure 1] FIG. 1 is a perspective view of a switch according to a first preferred embodiment applied to a closed access. [Diagram 2] FIG. 2 is a perspective view of the switch of FIG. 1 in an open access application. [Diagram 3] FIG. 3 is a perspective view of a switch with a handle according to the second preferred embodiment applied to a closed access; [Figure 4] FIG. 4 is a perspective view of the switch of FIG. 3 in an open access application. [Diagram 5] FIG. 5 is a perspective view of the switch of FIG. 3 with access closed. [Figure 6] FIG. 6 is a perspective view of the switch of FIG. 3 with access open. [Figure 7] FIG. 7 is a front view of the switch of FIG. [Figure 8] FIG. 8 is a bottom view of the switch of FIG. [Figure 9] FIG. 9 is a perspective view of the switch of the third preferred embodiment with a handle, with the access closed; [Figure 10] FIG. 10 is a perspective view of the switch of FIG. 9 with access open. BEST MODE FOR CARRYING OUT THEINVENTION

[0033] With reference to the accompanying drawings, three preferred, but not exclusive, configurations of a safety device according to the invention are shown, which are adapted to be applied to the access of a boundary or safety barrier arranged to protect a machine or industrial plant.

[0034] Typically, access A will be suitably equipped, by methods known and not described in detail below, with special electrical or electromechanical safety devices designed to prevent operation of the machine or plant or parts thereof when it is opened or when it is simply unlocked, or to send a signal that the unlocking or opening has occurred to allow operator intervention.

[0035] In Figures 1 and 2 the safety switch, generally designated 1, comprises an operating device 2 designed to be coupled to a movable part M of an access A to be monitored and, when the access A is opened, interacts with the power circuit of the machine or plant in the manner described below, also based on the characteristics of the machine or plant, to effect an immediate or timed shutdown.

[0036] In particular, the operating device 2 comprises a connecting body 3 designed to be fixed to a mobile part M of the access A, from which project holding elements 4 whose function will be described below.

[0037] The switch 1 also comprises a switching device 5 adapted to be connected to a fixed frame F of the access A to be monitored, which has at least one hole 7 arranged on the front side for the insertion of the holding element 4.

[0038] As is known, in order to compensate for misalignment and play between the two parts when they are assembled to the corresponding parts of the access A, the front hole 7 may be appropriately widened, and the retaining element 4 and the hole 7 may also have a centering function between the two devices 2, 5.

[0039] The casing 6 also has therein unillustrated locking / unlocking means suitable for interacting with the retaining element 4 when inserted inside the front hole 7 to prevent its extraction from the hole 7 and the possible opening of access A therewith if the predefined safety conditions for the machine or plant are not met.

[0040] The position of the holes 7 may also be varied appropriately depending on the insertion direction of the holding element 4 .

[0041] For example, in the case of access A with a sliding closure, hole 7 may be located on the side of casing 6 or may always be located on the front side of casing 6, which would be rotated 90° around a vertical axis with respect to the embodiment shown.

[0042] The configuration of the locking / unlocking means of the present invention is not limited, as any type of mechanism may be used to achieve mechanical retention of the retaining element 4, and may be mechanical, by means of a retainer or retractable teeth, or may engage with a magnetic block formed by an electromagnet (not shown) to lock it in the inserted position.

[0043] At this end, the holding element 4 will be provided with a groove 8 suitable for being engaged in the retainer described above.

[0044] The switching device 5 also houses switching means, not shown per se, suitable to be interfaced with one or more control and / or service circuits of the plant in order to control these.

[0045] Inside the casing 6 there are also arranged electrical and / or electronic control means suitable for being connected to one or more control and / or signalling circuits of the machine or plant for stopping the controller, controlling access, enabling the controller and / or sending reports.

[0046] Suitably, the retention mechanism will be controlled by control means which allow it to disengage from the retention and centering element 4 only when all conditions for the safe opening of the access A are met.

[0047] Also provided are safety detection means, not visible in the drawings, for detecting the opening of access A and adapted to verify that the operating device 2 is no longer in proximity to the switching device 5, in order to send a safe shutdown command of the machine or plant to said control means following detection of the opening of access A.

[0048] At the same time, also based on the degree of safety assigned to the switch 1, a control means may be connected to the locking / unlocking means in order to immediately or time-limitedly stop the machine or plant already following a request to open the holding element 4.

[0049] The switching device 5 also comprises further drive means 9 connected to the control means and adapted to send one or more activation / deactivation and / or signalling controls to the latter for an accompanying reaction by the machine or plant circuits.

[0050] In particular, the drive means 9 comprises a touch monitor 10 associated with the casing 6 .

[0051] The touch monitor 10 will have a number of virtual controllers which will be graphically reproduced on the monitor 10 and these functions will be suitably managed by a microprocessor connected to the monitor 10 to associate each virtual controller with a particular control and / or signalling function, such that each virtual controller will be associated by the control means with one of the circuits of the machine or plant.

[0052] In essence, each particular area of ​​the monitor 10 will be assigned, in a programmable manner, a particular function that replicates the functions of a conventional controller, such as an on / off button, a selector, a stop button, buttons for transmitting image and / or audio signals and / or for playing an image output signal.

[0053] Touching a particular virtual controller will send a particular signal from the microprocessor to the control means, which will operate on one or more circuits of the machine or plant to perform the action associated with the virtual controller in a manner entirely similar to that which would occur in an apparatus having a real controller.

[0054] Preferably, the actions assigned to the virtual controller will be actions with no safety function or will be safety controls if combined with a second external command or a specific sequence of screen touches on the screen.

[0055] Furthermore, according to a particular variant, the electrical and / or electronic control means may comprise one or more communication buses.

[0056] The communication buses may be adapted to convey data in either a secure or non-secure mode, based on the type of control with which they are associated.

[0057] According to a first variant, not shown, the touch monitor 10 would be integrated into the front face 11 of the casing 6 .

[0058] In the preferred but not exclusive configuration shown, the casing 6 comprises a first shell 12 housing the switching means and possibly the control means, and a second shell 13 connected to the first shell 12 and having an integrated touch monitor 10.

[0059] The first shell 12 and the second shell 13 may be integral with one another, or may be two distinct elements permanently connected to one another, and / or may be orientably connected so as to be relatively rotatable about a vertical axis in a position that is most comfortable for the user, or may simply be side-by-side without any connection.

[0060] For example, in the case of an access A with a sliding opening, it is possible to have a touch monitor 10 arranged at the front, but the first shell 12 is rotated 90° relative to the one shown, so that the hole 7 is arranged on the side and allows the insertion of a holding element 4 protruding further from the connecting body 3 along the sliding direction of the access A.

[0061] For added convenience and speed, the touch monitor 10 may be located on, and possibly integrated into, the front surface 14 of the second shell 13 so that there are no obstructions between the operator and the switching device 5.

[0062] The switching device 5 may also comprise an auxiliary release command 15, mechanical or electrical, such as a service or emergency command, suitable for interacting with a switching means, e.g. a selector, mushroom-head, emergency control cable, release key or similar, mechanically connected to the locking / unlocking means for emergency stopping of the machine, to control the circuits of the machine or system.

[0063] The auxiliary release controller 15 may be located on the casing 6, particularly on the front surface 11 of the first shell 12, but preferably in another location where it is easily accessible.

[0064] The detection means, not shown, comprise a transmitter associated with the connecting body 3 of the operating device 2 and adapted to transmit a presence signal, and at least one receiver associated with the casing 6 of the switching device 5 and adapted to receive a presence signal when the distance between the operating device 2 and the casing 6 is at least equal to a predetermined minimum value sufficient to close the access A, and to transmit this presence signal to control means capable of enabling the start of the system once other safety conditions are met.

[0065] As an example, the transmitter may be a transponder or tag / RFID that transmits a unique identification signal to an RFID (Radio Frequency Identification) receiver or antenna.

[0066] This tag / RFID may be replaced with a mechanical key or an electronic authentication system, such as data transmission via radio waves, via the Hall effect, through a magnetic field, via ultrasound or the like.

[0067] Advantageously, the RFID tag may be coded such that it can be uniquely recognised by control means connected to the receiver or antenna, preventing the use of actuators other than switch 1 and thus avoiding the risk of unsafe opening of access A, for example by known methods described in WO2013098788.

[0068] The manner in which the RFID tag is connected to the connecting body 3 is not limited and will not be described in detail. For the purpose of example only, the RFID tag may be housed in a specific sheet (not shown) formed inside the connecting body 3.

[0069] Advantageously, in order to further increase the security of the switch 1 and prevent unauthorized inputs, the control means may also be equipped with an identification device 22 for an operator authorized to intervene in the control means.

[0070] In particular, the casing 6 may be provided with an RFID reader arranged, for example at the front side 11 in the drawing or elsewhere, for operator recognition for dialogue with a token provided with an identification code owned by the operator.

[0071] The identification device 22 may be designed with multiple recognition levels so that certain functions are possible in different ways at various program levels.

[0072] The RFID reader 22 may be connected to the control means for inputting an identification code to be transmitted to the control means for comparison with a received and stored verification code.

[0073] As an alternative to the reader-token coupling, it would be possible to use other types of authentication systems, e.g. mechanical, e.g. by means of a key, as well as electronic, e.g. through authentication of biometric parameters.

[0074] According to further variants, additional devices such as indicator lights, selectors, potentiometers, emergency buttons, buzzers, badge readers for access control, fingerprint readers, iris readers, biometric readers or cameras for face recognition etc. and / or a different number of buttons may be applied to the casing 6.

[0075] In Figures 3 and 4 a second configuration of a switch, generally designated 100, is represented which comprises an operating device 102 with a connecting body 103 to the movable part M of the access A to be monitored, fitted with a handle 116 suitable for being grasped by a user in order to move the movable part M of the access A.

[0076] According to a preferred, but not exclusive, embodiment of the figures, the handle 116 is movably attached to the connecting body 103 and adapted to move relative to the connecting body 103 between at least two positions.

[0077] As an example, the handle 116 may be hinged to the connecting body 103 so that it can be raised and lowered in the same manner as occurs with a normal lever handle, or it may be a slide type or a rotating knob type, but is not limited thereto.

[0078] The handle 116 is movably housed inside the connecting body 103 and may be connected by a suitable transmission mechanism (not shown) to a holding element, e.g. a pin or bolt 104, having a holding function and possibly a centering element.

[0079] In this way, following movement of the handle 116 from the first raised position depicted in FIG. 3 to the second lowered position depicted in FIG. 4, the bolt 104 may be moved from an extraction position in which access A is closed, although not necessarily blocked, to a position suitable for opening access A which is at least partially stored within the connecting body 103.

[0080] In a manner not shown, substantially similar to a conventional door handle, the handle 116 may be associated with a first elastic recovery mechanism adapted to automatically guide the bolt 104 from the second lowered position to the first raised position with the bolt 104 locked in the extracted position.

[0081] According to a variant not shown, the handle 116 may be fixed relative to the connecting body 103, for example formed as one piece, in which case the bolt 104 may be moved simply by stress transmitted by contact with a part of the switch 100 connected to the fixed part F of the access A.

[0082] The bolt 104 may further be associated with a second elastic recovery mechanism operable to return it from the at least partially retracted position to the extracted position such that it is always in the extracted position and is retracted only following an inward thrust caused by action of the handle 116 or contact with a portion of the switch 100 coupled to the fixed portion F of the access A.

[0083] According to a further variant not shown, the extraction and retraction of the bolt 104 may be operated by a remotely controlled electromechanical mechanism or by a command button located on the connecting body 103 or on the handle 116.

[0084] The switch 100 also comprises a switching device 105 having a casing 106 adapted to be connected to a fixed frame F of the access A to be monitored and having at least one side hole 107 for the insertion of the bolt 104.

[0085] The casing 106 also houses internal locking / unlocking means, not shown, suitable for interacting with the bolt 104 to prevent return to the retracted position or vice versa when the bolt 104 is inserted within the side hole 107 in the fully extracted position.

[0086] Advantageously, the casing 106 may be provided with two holes 107 arranged on opposite sides 117, 118, into one of which the bolt 104 may be selectively inserted depending on whether the connecting body 103 is mounted on the right or left side in relation to the switching device 105, in order to interact with the locking / unlocking means from the right or left side.

[0087] 5 and 6 in fact represent a switch 100 with the handle 116 mounted on the right side of the switching device 105, while FIGS. 9 and 10 represent a switch 100 with a handle 116 substantially the same as the previous one but mounted on the left side of the switching device 105.

[0088] According to a variant not shown, one or more insertion holes 107 for the bolts 104 may be formed in the front face 111 or in one or both of the upper face 119 and the lower face 120 of the casing 106 .

[0089] In this case, the bolt 104 may protrude from the connecting body 103 to the left and right or from the front.

[0090] The bolts 104 may have ends designed to be inserted into appropriately flared or rounded holes 107 in the casing 106 to help compensate for any misalignment between the two parts of the switch 100, thus also functioning as centering elements.

[0091] The configuration of the locking / unlocking means of the present invention is not limited and any type of mechanism can be used to achieve mechanical retention of the bolt 104, which is mechanically engaged by a retention element to lock it in the closed access extraction position.

[0092] At this end, the free end of the bolt 104 may be provided with a groove or slot suitable for being engaged with a retaining element of a locking / unlocking mechanism.

[0093] The electrical and / or electronic control means are suitably arranged in the casing 106 for connection with one or more control and / or signalling circuits of the machine or plant for transmitting stop, mobilisation and / or signalling commands, also via a safe or non-safe communication bus.

[0094] Suitably, the retention mechanism may be controlled by a control means which will only allow the retention mechanism to be released from the bolt 104 when all safety conditions for the opening of access A have been confirmed.

[0095] As represented in FIG. 8 , the casing 106 comprises further devices such as one or more connectors 121 for transmitting data, electrical signals, power supply, etc., a selector 123, which may be manually operated by a suitable tool for the mechanical opening of the bolt 104.

[0096] There are also detection means, not visible in the drawings, for detecting the opening of access A, similar to those described for the previous configuration, adapted to verify that the mobile connecting body 103 is no longer in proximity to the fixed casing 106, in order to send a machine or plant stop command to said control means following detection of the opening of access A.

[0097] At the same time, also based on the safety degree assigned to the switch 100, the control means may be connected to the locking / unlocking means, which when the bolt 104 is already unlocked, performs an immediate or timed shutdown of the machine or plant or sends an access request signal and a resulting stop of the machine or system.

[0098] The operating device 103 also comprises further drive means 109 connected to the control means and adapted to send one or more activation / deactivation and / or signalling commands to the latter for an accompanying reaction by the machine or plant circuits.

[0099] In particular, the drive means 109 comprises a touch monitor 110 associated with the casing 106 and which, in the preferred but not exclusive configuration of the figures, is integrated into the front face 111 .

[0100] The touch monitor 110 is provided with a number of virtual controllers which are graphically reproduced on the monitor 110 and whose functions are suitably managed by a microprocessor connected to the monitor 110 for associating each virtual controller with a particular control and / or signalling function, which is associated by the control means with one of the safe or non-safe circuits of the machine or plant.

[0101] In short, specific functions will be assigned in a programmable manner to each specific area of ​​the monitor 110, such as warning signals, alarms, machine operation information, access status, reproducing the functions of conventional commands such as on / off buttons, selectors, stop buttons, image and / or audio signal transmission and / or image output signals, and also reproducing video with or without audio and possibly many screens that can be slid by touch at any time.

[0102] Touching a particular virtual controller will cause a particular signal to be sent from the microprocessor to a control means operating on one or more circuits of the machine or plant, and from the microprocessor to the control means to perform the action associated with the virtual controller, in a manner completely analogous to what would occur in a device with real commands.

[0103] The actions delegated to the virtual controller may be either actions without safety features or actions with safety features.

[0104] For added convenience and speed of use, the touch monitor 110 may be located on, and possibly integrated into, the front of the casing so that there are no obstructions between the switches and the operator.

[0105] According to another variant, several monitors may be arranged at a distance from each other on different sides of the casing.

[0106] For safety reasons, the switching device 105 may also be equipped with a physical emergency button, preferably a mushroom 115 connected to a locking / unlocking means for emergency stopping of the machine.

[0107] An emergency button 115 is preferably located on the front face 111 of the casing 106 for quick access, but may be provided elsewhere.

[0108] The detection means, not shown, comprise a transmitter associated with the connecting body 103 and adapted to transmit a presence signal, and at least one receiver associated with the casing 106 and adapted to receive a presence signal when the distance between the connecting body 103 and the casing 106 is at least equal to a predetermined value sufficient to consider the access A closed, and to transmit this presence signal to control means capable of enabling the start of the system once other safety conditions are confirmed.

[0109] As an example, the transmitter may be a transponder or tag / RFID, or any other transmission means, that transmits a unique identification signal to an RFID receiver or antenna.

[0110] Advantageously, the RFID tag may be coded such that it can be uniquely recognised by a control means connected to the receiver or antenna, and may prevent the use of actuators other than switch 100, thereby avoiding the risk of unsafe opening of access A, by known methods, for example as described in WO2013098788.

[0111] The manner in which the RFID tag is connected to the connecting body 3 is not limited and will not be described in detail. By way of example only, the RFID tag may be locked to a specific sheet (not shown) formed inside the connecting body 103.

[0112] Advantageously, again in this case, in order to further increase the security of the switch 100 and prevent unauthorized access, the control means may also comprise an identification device 122 of an operator authorized to intervene in the control means, comprising an RFID reader for operator recognition adapted to dialogue with a token provided with an identification code in the possession of the operator.

[0113] The aesthetic and structural configuration of the connecting body 103 and associated handle 116 may vary depending on requirements.

[0114] For example, according to a first variant, the connecting body 103 may consist of a connecting bracket to the movable part M of the access A and a cover shell suitable to be fixed to the bracket by means of screws, pins or similar anchoring organs, or by a snap coupling.

[0115] According to a further variant, the bracket may consist only of a shell provided with a handle 116 .

[0116] In addition, the fastening element of the connecting body 103 may be provided with sealing means (not shown) suitable for covering it to prevent access thereto and to provide evidence in case of removal by unauthorized persons.

[0117] For example, the sealing means may be an anti-theft cap disposed inside a hole in the coupling body 103 designed to receive the connecting member.

[0118] The anti-theft caps would be designed to fit snugly into the corresponding through-holes so as to eliminate any elements that would facilitate their extraction, and to break when removed so as to prevent their reinsertion and provide direct evidence of any attempted removal.

[0119] In this way it would be impossible to detach the connecting body 103 or to dismantle this part without leaving traces of similar actions.

[0120] Similar fastening members and associated sealing means may also be associated with the switching device 105 .

[0121] In this way, the switch 100 will always be adequately protected against any action aimed at even partially disconnecting or dismantling it, which could lead to an unsafe state of access A.

[0122] The switch according to the invention is susceptible to numerous modifications and variations, all of which are within the inventive concept as expressed in the appended claims. All details can be replaced by other technically equivalent elements and the article can vary according to requirements, without departing from the scope of protection of the invention.

Claims

1. A safety switch for monitoring access (A) to a machine or industrial plant, comprising: a switching device (5, 105) having a casing (6, 106) adapted to be coupled to the fixed part (F) of said access (A) to be monitored and housing switching means adapted to be connected to one or more control circuits and / or service circuits of said machine or plant for controlling them, and electrical and / or electronic control means adapted to be connected to said one or more control circuits and / or service circuits of said machine or plant; an operating device (2, 102) adapted to be coupled to a movable part (M) of said access (A) and which interacts with said switching means when said access (A) is opened / closed for opening / closing said one or more control circuits and / or service circuits; - detection means for detecting the opening of said access (A), associated with said switching device (5, 105) and with said operating device (2, 102), which upon said detection or a request for the opening of said access (A) send a stop command for said machine or plant to said control means; - drive means (9, 109) connected to said control means for transmitting activation / deactivation and / or signaling controls, A safety switch, characterized in that the actuation means (9, 109) comprise at least one touch monitor (10, 110) integrated in the casing (6, 106) and equipped with one or more virtual controllers associated with respective actions, and at least one microprocessor suitable for associating said one or more virtual controllers with control and / or signalling functions and which by means of said control means associates said one or more virtual controllers with one of the circuits of the machine or plant.

2. 2. A safety switch according to claim 1, characterized in that the at least one touch monitor (10, 110) is arranged on one side (11, 111) of the casing (6, 106).

3. 2. The safety switch according to claim 1, characterized in that the casing (6) comprises a first shell (12) housing the switching means and a second shell (13) orientably connected to the first shell (12), and in which the touch monitor (10) is integrated.

4. 2. A safety switch according to claim 1, characterized in that the operating device (2, 102) comprises a retaining element (4, 104) adapted to be inserted into a hole (7, 107) formed in the casing (6, 106) when the access (A) is closed, and to interact with locking / unlocking means housed in the casing (6, 106), the retaining element being adapted to engage and prevent extraction from the casing (6, 106).

5. 5. The safety switch according to claim 4, characterized in that the retaining element (104) is a pin or a bolt movable within the operating device (102) to pass from an extraction position of the closed access (A) to a position at least partially stored within the operating device (102), whereby the access (A) can be opened, the operating device (102) comprising a connecting body (103) and a handle (116) mechanically connected to the retaining element (104) and movably attached to the connecting body (103) to move relative to the connecting body (103) between at least one first position and one second position, the handle (116) carrying the retaining element (104) from the extraction position to the at least partially stored position following movement from the first position to the second position.

6. 5. A safety switch according to claim 4, characterized in that the casing (6, 106) comprises a pair of holes (7, 107) arranged on opposite faces thereof for selective insertion of the holding elements (4, 104) and interaction with the locking / unlocking means.

7. 2. A safety switch according to claim 1, characterized in that the casing (6, 106) is provided with an auxiliary release command (15) and / or an emergency button (115).

8. 2. A safety switch according to claim 1, characterized in that the detection means comprises: a transmitter associated with the operating device (2, 102), adapted to transmit a presence signal; and at least one receiver associated with the switching device (5, 105), adapted to receive the presence signal when a distance between the switching device (5, 105) and the operating device (2, 102) is at least equal to a predetermined value sufficient to accept that an access (A) is closed, and to transmit the presence signal to the control means.

9. 5. A safety switch according to claim 4, characterized in that the locking / unlocking means comprise an identification device (22, 122) of an operator having the right to intervene in the control means, and an RFID tag connected to the control means for receiving, when an identification code to be transmitted to the control means is entered, and for comparing it with a memory verification code.

10. 6. A safety switch according to claim 5, characterized in that the locking / unlocking means comprise a mechanical retaining mechanism adapted to engage and lock the retaining element (4, 104) in the extraction position of the closed access (A).

11. 2. A safety switch according to claim 1, characterized in that the electrical and / or electronic control means comprise one or more communication buses for data transmission.

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